G Model
ARTICLE IN PRESS
RESUS 6177 1–6
Resuscitation xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
1
Clinical paper
2
Does the sex of a simulated patient affect CPR?夽
3
Q1
4 5 6 7 8
Q2
Chelsea E. Kramer a,c , Matthew S. Wilkins b,c , Jan M. Davies b,c,d , Jeff K. Caird b,c,∗ , Gregory M. Hallihan c a
Department of Psychology, Laval University, Laval, QC, Canada Department of Psychology, University of Calgary, Calgary, AB, Canada Healthcare Human Factors and Simulation Laboratory, W21 C Research and Innovation Centre, University of Calgary, Calgary, AB, Canada d Department of Anesthesia, Faculty of Medicine, University of Calgary, Calgary, AB, Canada b c
9
10 24
a r t i c l e
i n f o
a b s t r a c t
11 12 13 14 15
Article history: Received 24 June 2014 Received in revised form 10 October 2014 Accepted 19 October 2014
16
23
Keywords: Sex differences Cardiopulonary resuscitation (CPR) Automated external defibrillators (AEDs) Bystander resuscitation Experimental research Patient simulation
25
1. Introduction
17 18 19 20 21 22
26 27 28 29 30 31 32 33 34
Introduction: While males and females are equally at risk of sudden cardiac arrest (SCA), females are less likely to be resuscitated. Cardiopulmonary Resuscitation (CPR) may be inhibited by socio-cultural norms about exposing female victims’ chests. Empirically confirming this hypothesis is limited by lack of patient simulators modeling realistic female physiques. A commercially-available patient simulator was transformed to evaluate how physical attributes of a patient’s sex might influence lay participants who were asked to resuscitate a female versus a male during simulated cardiac arrest. Methods: Sixty-nine participants consented to be in the study. Participants were randomly assigned to provide CPR and defibrillation as instructed by a commercially-available automated external defibrillator on a patient simulator presented as either a male or female experiencing cardiac arrest. Results: Rescuers removed significantly more clothing from the male than the female, with men removing less clothing from the female. More rescuers’ initial hand placements for CPR were centered between the female’s breasts compared to the male, on which placement was distributed across the chest towards the nipples. Discussion: While rescuers had better hand placement for CPR on the female, both men and women rescuers were reluctant to remove the female’s clothing, with men significantly more hesitant. Reticence to remove clothing was often articulated relative to social norms during structured interviews. We suggest that using only male simulators will not allow trainees to experience social differences associated with the care of a female simulated patient. Realistic female patient simulators are needed. © 2014 Elsevier Ireland Ltd. All rights reserved.
Early Cardiopulmonary Resuscitation (CPR) is a key link in the resuscitation “chain of survival” for Sudden cardiac arrest (SCA).1 While female sex increases the probability of survival to hospital from out-of-hospital cardiac arrest (OHCA) after bystander or formal resuscitation,2–7 women are less likely to receive such care from both lay2,5–7 and medically-trained personnel.5,8 However, reasons for this difference are either not discussed2,8 or only suggested but not supported by data.5,6 For example, Ahn and colleagues postulated that cultural reasons contributed to not
夽 A Spanish translated version of the abstract of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2014.10.016. Q3 ∗ Corresponding author at: Department of Psychology, University of Calgary, 2500 University Dr. N. W. Calgary, Alberta, Canada T2N1N4. E-mail address: [email protected] (J.K. Caird).
removing clothing from females’ upper chests in an out-of-hospital setting.5 To our knowledge no studies support or refute the conjecture that ‘sex matters’. Typically, CPR training and research tend to use one type of simulator, either torso mannequins (Laerdal’s Little Anne® )9 or full body mannequins (SimMan® ).10,11 Although medical simulators are considered “realistic models of real patients”12 and educationally useful,13 they have been described as having “perceived low levels of realism”.14 This comment was made in reference to simulation’s utility in midwifery education, but could also be applied to female patients. We therefore questioned the assumption that current patient simulators are sufficient both to train and to understand the behavior of caregivers with respect to male and female patients. We hypothesized that physical attributes of a patient’s sex might influence lay participants when resuscitating a female versus male victim during simulated cardiac arrest. For example, an undergarment (e.g., a brassiere) would require direct garment manipulation
http://dx.doi.org/10.1016/j.resuscitation.2014.10.016 0300-9572/© 2014 Elsevier Ireland Ltd. All rights reserved.
Please cite this article in press as: Kramer CE, et al. Does the sex of a simulated patient affect CPR? Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2014.10.016
35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
G Model RESUS 6177 1–6
ARTICLE IN PRESS C.E. Kramer et al. / Resuscitation xxx (2014) xxx–xxx
2
60
(e.g., unclasping or cutting) to ensure the rescuer “remove[s] all clothing from [the] patient’s chest”15 (as instructed by an automated external defibrillator (AED)) before successful defibrillation. We postulated such considerations, as well as social factors, could hinder complete clothing removal from a female simulated patient, as well as determine where on the chest rescuers initially placed their hands to perform CPR. Our primary outcome measures were percentage of clothing removed and placement of rescuers hands.
61
2. Method
62
2.1. Participants
53 54 55 56 57 58 59
76
The University of Calgary’s Biomedical Ethics Committee certified the study and 69 undergraduate students volunteered through the University’s research participation system. Participants received one course credit in exchange for participation. Participants were screened for English fluency and near visual acuity (to 40 cm), which approximated the distance required for AED interaction. The total number of participants recruited was based on a previous AED study16 and effect size estimates.17 Participants were quasi-randomly assigned to either the male or female simulator depending on the timing of participant sign-up, the time required to make the sex change of the patient simulator and the necessity to equilibrate men and women in each simulator group. Participants were not given any information about the nature of the study except that AED use was being examined.
77
2.2. Equipment and setting
63 64 65 66 67 68 69 70 71 72 73 74 75
95
Patient Simulator. A commercially available patient simulator (METI iStan® ) was used in the control condition (Fig. 1, left). iStan was modified to represent a female victim in the experimental condition (iSamantha or ‘iSam’; Fig. 1, right). Transformation from male to female involved use of a wig, make-up, silicone breasts, a front-opening brassiere and color-coordinated women’s clothing. AED. Participants performed all simulation OHCA scenarios using a Medtronic LifePak CR® + AED (training version). Simulation Laboratory. The study was conducted in the Healthcare Human Factors and Simulation Laboratory (HHFSL) at the W21 C Research and Innovation Centre at the University of Calgary (www.w21c.org). The HHFSL has simulation and control rooms. The former contains four directional microphones and four ceiling mounted cameras with pan, tilt and zoom capabilities to record participant, AED and patient simulator interactions. Participants were also observed in real-time through a one-way window from the control room containing observational and analytical hardware and software systems.
96
2.3. Procedure
78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94
97 98 99 100 101 102 103 104 105 106 107 108 109 110 111
Upon arrival, participants gave informed consent, provided demographic information and were introduced to the simulator room containing the male or female patient simulator. Each participant was oriented to the patient simulator and how it functioned. Participants were told they would be rescuing an unconscious patient from cardiac arrest. Once they understood what they would be doing during the study they exited the simulator room with the experimenter. The OHCA scenario began when the experimenter and participant re-entered the room to find either iStan or iSam on the floor in an apparent state of arrest. Each participant was given an AED and a barrier mask for rescue breaths. No instructions on CPR or the use of the AED were provided. The experimenter left the room under the pretense of going “to go call an ambulance”. Participants had to work through the operation of the AED on their own. Once
activated, the AED provided verbal commands to guide participants through each of five steps: (1) open case; (2) activate AED; (3) position electrode pads; (4) deliver shock; and (5) administer CPR. The AED was programmed to deliver two shocks. The first shock was always unsuccessful so the rescuer had to perform CPR. The AED instructed the participant to “provide chest compressions and rescue breaths”. To avoid undue psychological distress, delivery of the second shock was always followed by programmed recovery of the simulated patient, regardless of the individual’s performance with the AED. When the OHCA scenario was over, participants underwent a structured interview about their experience, including an understanding of removal of the patient’s clothing, their reservations (if any) in doing so, their potential degree of comfort in resuscitating a patient and perceptions about the patient. Participants were also debriefed on proper AED technique and given information about available CPR training courses. The entire study took approximately 45 min for each participant to complete. 2.4. Experimental design and statistical analysis The video and audio from the OHCA scenario were recorded by Noldus Media Recorder, coded with Noldus Observer® XT (v. 9.0) and analyzed using IBM SPSS® (v. 19). Chi-square tests and MannWhitney U tests were used to test primary outcome measures in the experimental design of simulated patient sex (male vs. female) and rescuer sex (men vs. women). Specifically, the primary outcome measures (POM) were: (1) the percentage of rescuers who completely removed clothing from the simulated female patient’s chest compared to the simulated male’s and (2) the placement (position, orientation and classification) of rescuers’ hands when CPR was initiated. The first POM was determined by viewing the video images. Clothing removal was scored as complete or incomplete. To determine the second POM, photographs of iStan’s and iSam’s chests were taken from the same perspective (frontal view) and location to ensure identical sizes of and proportions between the two images (error = ±4 pixel). The clavicles, sternal notch, nipples, xiphisternum and distal rib cage served as anatomical landmarks. A single coder used these landmarks and multiple camera angles/video images to select an image best showing initial placement of each rescuer’s hands. For hand position and orientation, a researcher reviewed the recorded participant data. Based on initial hand placement at the onset of CPR, each rescuer’s left and right hands were plotted on a schematic of iStan or iSam’s chest, starting from the base of the palm to the longest point of the middle finger. If the hand was curled, the length was marked as the most distal knuckle. Each hand was thus represented as a line from palm to (usually) the middle finger on iStan’s or iSam’s chest. In addition, the mid-point of the distal (i.e., base) palm of the lower hand was determined (as the distal central point of pressure) and marked as a dot on the line. Each (hand) line was compared to two lines on the simulator’s body: a nipple-nipple line (x-axis) and a cephalad-caudad line through the body’ midline (y-axis). This comparison thus showed position and orientation of the hands to these lines on the simulated patient’s chest. For hand placement classification, two concepts were used, one of which was established CPR guidelines.18 The other was that of “correct position, incorrect position and dangerous areas” for safe and effective CPR, described by Diószeghy and colleagues.19 We superimposed their diagram of the anterior chest showing three corresponding rectangular areas–‘green’ (“correct”), ‘yellow’ (“incorrect”) or ‘red’ (“dangerous”) zones for CPR [19]–onto a video
Please cite this article in press as: Kramer CE, et al. Does the sex of a simulated patient affect CPR? Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2014.10.016
112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129
130
131 132 133 134 135 136 137
138 139 140 141 142
143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173
G Model
ARTICLE IN PRESS
RESUS 6177 1–6
C.E. Kramer et al. / Resuscitation xxx (2014) xxx–xxx
3
Fig. 1. Male iStan (left), and female iSam (right).
179
image of each rescuer’s initial hand position. Distal hand positions within the ‘green/yellow’ and within/outside the ‘red’ zone were counted for both iStan and iSam. Participants who did not attempt chest compressions (n = 2) or separated their hands rather than placing one on top of the other (n = 9) were excluded from this analysis.
responders who completely removed clothing also differed significantly between rescuer sex for iSam, X2 (1, 33) = 9.53 p = 0.002). Men rescuers (n = 2/15 removed or 13.3%) were significantly less likely to completely de-robe iSam than were women rescuers (n = 12/18 removed or 66.7%). There was no difference between men and women in de-robing iStan.
180
3. Results
3.3. Hand placement
181
3.1. Participant characteristics
Fig. 3 shows both hands of participants on iStan (left) and iSam (right). Lines represent initial hand placements from the base of the palm to the longest point of the middle finger, with dots indicating the center of the distal palm. Men rescuers are represented as blue and women as pink lines in the color images, respectively. Placement of participants’ hands on the chest differed if the simulated patient was male or female. Participants who performed CPR on iStan showed more variability in hand placement over a greater area of the chest (Fig. 3, left). Placement of hands on iSam tended to be centered between the breasts (see Fig. 3, right). The location of participants’ hands with respect to the green, yellow and red zones is shown in Fig. 4. A Chi-square test of hand placement in green/yellow and ‘red’ zones was significant X2 (1, 57) = 4.3, p < .039 (see Fig. 5). Initial hand placement on iStan was significantly less accurate than on iSam. Within the iSam group, a greater proportion of participants placed their hands within the green/yellow zones (48.4%) than with iStan (22.2%).
174 175 176 177 178
186
Table 1 shows the characteristics of our sample of participants. An approximately equal number of men and women of similar ages and CPR/AED training were in either the iStan or iSam groups. There were no group differences for either AED or CPR training (see Table 1).
187
3.2. Clothing removal
182 183 184 185
188 189 190 191 192 193 194
A Chi-square test was performed to test the relationship between patient sex (male vs. female) and rescuer sex (men vs. women). Fig. 2 shows that the proportion of rescuers who completely removed a patient’s clothing differed significantly between patient simulators X2 (1, 69) = 19.22, p < 0.001. Rescuers were more likely to completely bare iStan’s chest (n = 33/36 removed or 91.7%) compared to iSam’s (n = 14/33 removed or 42.4%). The percent of
80 60 Complete clothing removal (%)
Men Rescuers Women Rescuers
40 20 0 Male Patient
Female Patient
Patient Simulator Fig. 2. Percent of men and women rescuers who completely removed clothing from chest of male and female patient simulators.
197 198 199 200
202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218
219
The purpose of this study was to determine if CPR for an OHCA scenario was performed differently for a simulated male versus female patient. Sixty-nine lay participants were quasi-randomly assigned to a male or female patient simulator and asked to resuscitate the simulated patient with AED guided CPR. We found performance of specific CPR steps was influenced by the apparent sex of the simulator and the sex of the participants, who had been blinded to the purpose of the study. Removal of clothing. Both men and women rescuers were reluctant to remove iSam’s clothing (see Fig. 2). Only 42% (n = 14) of all participants removed both iSam’s blouse and brassiere. In comparison, previous studies with the same simulated male patient showed all participants completely bared iStan’s chest.16,20
Table 1 Study participant demographics and experience.
Mean age (SD) Sex AED experience CPR training within the last 5 years
196
201
4. Discussion
100
195
Male patient simulator (N = 36)
Female patient simulator (N = 33)
Significance
21.8 (5.2) 16 Male, 20 female 9 (25.0%) 11 (30.6%)
24.0 (8.4) 15 Male, 18 female 5 (15.1%) 11 (33.3%)
NS (p = 0.21) NS (p = 0.93) NS (p = 0.34) NS (p = 0.74)
Please cite this article in press as: Kramer CE, et al. Does the sex of a simulated patient affect CPR? Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2014.10.016
220 221 222 223 224 225 226 227 228 229 230 231 232
G Model RESUS 6177 1–6 4
ARTICLE IN PRESS C.E. Kramer et al. / Resuscitation xxx (2014) xxx–xxx
Fig. 3. Initial placement for CPR of both hands on male (left) and female (right) simulators. Dots show the center of the palm of the bottom hand and lines represent the length of the longest extended finger. Blue lines represent male rescuers and pink lines represent female rescuer. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
233 234 235 236 237 238 239 240 241 242 243 244 245 246 247
Men were significantly more hesitant than women to remove iSam’s clothing. Only two men removed the brassiere. When interviewed about their decisions not to do so, participants most often responded they thought they needed only to remove enough clothing to place the defibrillator pads according to instructions rather than ensuring the brassiere would not affect CPR. During interviews, reticence to remove clothing was often articulated relative to social norms. Apparently concerned for patient modesty, men did not want to remove more clothing than necessary. Of note, we chose to use a front-opening brassiere because of the simulator’s weight and not wanting participants to cut the brassiere. Our results therefore might underestimate the real life difficulties of removing a back-opening brassiere. Our study with a simulated female patient suggests clear AED instructions about clothing removal from a female patient’s chest
could affect CPR performance for a female patient. Our results are consistent with other research.21 Merrigan had participants rate photographed vignettes of a (simulated) male or female victim in cardiac arrest with photographs of a man or woman rescuer of three different ethnic groups (European, Indian Sub-Continent and Arab). Participants (n = 345) expressed lower acceptability ratings for Indian men to rescue female patients, but no differences were found for the ethnicities of other men.21 The results of Merrigan’s study and ours suggest that female victims of OHCA may be less likely to be resuscitated due to cultural taboos of exposing a female’s breasts in public. Further support for this suggestion comes from two publications. In one, female patients were less likely than males to receive CPR from “policemen”.2 In another, the statement was made that when resuscitating a female patient in public, “chest exposure
Fig. 4. Locations of hand placement for CPR superimposed on male (left) and female (right) patient simulators. Dots show the center of the palm of the bottom hand and lines represent the length of the longest extended finger. Blue lines represent male rescuers and pink lines represent female rescuers. Participants whose hands did not overlap (n = 9) were excluded from this analysis. [Anatomic and zone overlay reprinted from Diószeghy et al. Comparison of effects of different hand positions during cardiopulmonary resuscitation. Resuscitation 2005; 66: 297–301, with permission from Elsevier.]. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
Please cite this article in press as: Kramer CE, et al. Does the sex of a simulated patient affect CPR? Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2014.10.016
248 249 250 251 252 253 254 255 256 257 258 259 260 261 262
G Model
ARTICLE IN PRESS
RESUS 6177 1–6
C.E. Kramer et al. / Resuscitation xxx (2014) xxx–xxx 25
4.1. Limitations and future research
20
Although the artificial breasts used were somewhat realistic, their appearance was more representative of those of a younger woman and not those of someone older who might have breasts with “Cooper’s droop”.28 This limitation is important because it was difficult to match iSam’s physical characteristics with those of iStan (used in previous studies). During post-study interviews, participants suggested iStan was about 33 years old, while iSam appeared older—about 45 years. iStan’s suggested age corresponds to the fact his original design was based on a real 30-year old man. iSam appeared older, partly because of her large-sized clothing and her bulky (simulator) body. In addition, the mannequin’s heavy-set facial features, even with carefully applied wig and make-up, gave the impression of a more ‘mature’ woman. It is possible that some participants’ perception of iSam’s age could have subtly affected their willingness to intervene in a realistic manner with a simulated OHCA victim. In fact, many participants stated “old age” was a potentially inhibiting factor in their willingness to perform CPR. It was difficult to find a sample of participants without any CPR training. Ten students reported receiving basic CPR in their high school curriculum, which for some also included exposure to AEDs. Nevertheless, many who reported some training in the past five years still failed to remove either patient’s clothes and/or demonstrated incorrect initial hand placement for CPR. The results of our study may actually be optimistic when extrapolating to the real world. Our participants were younger and had higher levels of education than would be expected of the general public, potentially contributing to an overly positive portrayal of iSam’s care. Members of the public might be more hesitant to disrobe an actual female patient. Furthermore, the effect of presence of others on a rescuer’s willingness to completely remove a female patient’s clothing from her chest is not known. During structured interviews, some of our participants stated having bystanders present might hinder them, while others said that bystanders would make them more comfortable. Such reticence is a complex matter, with personal, contextual and social contributors, including not wanting to be involved or to touch bare skin, in addition to cultural reasons.26 While there are many questions to be addressed by future research, we suggest the most important question is: How do we determine the most effective way to overcome societal and cultural inhibitions so that we can provide better care for female patients? As we already know, improving care for women with cardiovascular disease is a fundamental principle.29
15
Male Simulator
Number of Participants
Female Simulator
10
5
0
Inside Yellow/Green Zones
Inside or Outside Red Zone
Initial Hand Placement Fig. 5. Frequency of initial hand placement (bottom hand) within the ‘green/yellow’ zones and inside or outside the ‘red’ zone on male and female patient simulators. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306
5
should be limited to the area where the defibrillation pads are applied, after which the chest wall may be covered by the patient’s own clothing”.22 Part of the author’s explanation for this was “to give due respect to women”.22 Having respect for all patients, regardless of their sex, is central to the practice of medicine, as espoused in the Hippocratic Oath.23 While re-covering a woman’s “chest wall” with her own clothing could be seen as implying a particular type of “respect for women”, the act of replacing clothing and the presence of the clothing could also impede resuscitative efforts. As Meaney and colleagues emphasized, the inherent inefficiency of CPR “highlights the need for trained rescuers to deliver the highest-quality CPR possible”, including a “standardized approach”.24 Mortensen and colleagues compared the quality of chest compressions on a dressed versus undressed mannequin and found no significant differences in CPR.25 Chavez and colleagues demonstrated compression depth, rate and release were no worse when a mannequin’s clothing was not removed.26 However, Mortensen et al. commented that rescuers might have “no option but to occasionally unclothe the thorax” to apply AED pads.25 Similarly, Chavez and colleagues stated clothing would have to be removed to apply AED pads.26 Thus, for AED-guided CPR, removal of clothing would remain third on the list of instructions. Hand placement. Clinically, initial hand placement is important. However, a number of participants did not know where to position their hands when performing compressions, as shown by hand placement outside the ‘red’ zone of the chest. Chest compressions in these areas could result in harm.19 These incorrect hand placements are likely representative of lay rescuers who had not received CPR instruction immediately before testing. Guidance as to where rescuers should place their hands could be improved by instructor feedback27 and clear AED verbal/pictorial instructions. On iStan, hand placement tended to be distributed across the chest (see Fig. 3, left). In contrast, on iSam, rescuers’ hands were more centralized over the sternum—and not generally over the breasts. We were unable to determine if rescuers attempted to avoid touching iSam’s breasts or if these ‘landmarks’ aided the lay rescuers in choosing better hand placement. In addition, although we did not measure CPR effectiveness, the better hand placement on iSam’s chest could have resulted in improved CPR. Nevertheless, social norms appeared to constrain both clothing removal and hand placement for CPR on the female simulator. This was an unexpected finding.
5. Conclusion We hypothesized that physical attributes of a patient’s sex might influence lay participants when resuscitating a female versus male during simulated cardiac arrest. Our results suggest that the sex of a simulated patient does affect CPR, with participants being more reluctant to remove clothing from the female compared to the male simulated patient. Rescuers were more likely to centre their hands between the female’s breasts than with the male, on which hand placement was distributed across the chest towards the nipples. Our results suggest individuals may interact differently with females than males when responding to OHCA. The absence of realistic female patient simulators may bias training for and research into patient care.
Conflict of interest statement The authors have none.
Please cite this article in press as: Kramer CE, et al. Does the sex of a simulated patient affect CPR? Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2014.10.016
307
308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350
351
352 353 354 355 356 357 358 359 360 361 362 363
364
365
G Model RESUS 6177 1–6
C.E. Kramer et al. / Resuscitation xxx (2014) xxx–xxx
6 366
ARTICLE IN PRESS
Acknowledgments
We thank Ruth Diaz, Jessica Jones, Aimee Pearson, Nicole Percival, and Elise Teteris for assistance. This research was facilitated 368 Q4 through generous support of the Calgary Health Trust, the National 369 Q5 Science and Engineering Research Council and W21 C, the latter 370 funded by a Western Economic Development grant that paid for 371 the study’s capital equipment. 372 367
373
374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407
References 1. Cummins RO, Ornato JP, Thies WH, Pepe PE. Improving survival from sudden cardiac arrest: the “Chain of Survival” concept. A statement for health professionals from the Advanced Cardiac Life Support Subcommittee and the Emergency Cardiac Care Committee American Heart Association Writing Group. Circulation 1991;83:1832–47. 2. Herlitz J, Engdahl J, Svensson L, et al. Is female sex associated with increased survival after out-of-hospital cardiac arrest? Resuscitation 2004;60:197–203. 3. Mahapatra S, Bunch TJ, White RD, Hodge DO, Packer DL. Sex differences in outcome after ventricular fibrillation in out-of-hospital cardiac arrest. Resuscitation 2005;65:197–202. 4. Teodorescu C, Reinier K, Uy-Evanado A, et al. Survival advantage from ventricular fibrillation and pulseless electrical activity in women compared to men: the Oregon Sudden Unexpected Death Study. J Interv Card Electrophysiol 2012;34:219–25. 5. Ahn KO, Shin Do S, Hwang SS. Sex disparity in resuscitation efforts and outcomes in out-of-hospital cardiac arrest. Am J Emerg Med 2012;30:1810–6. 6. Bray JE, Stub D, Bernard S, Smith K. Exploring gender differences and the “oestrogen effect” in an Australian out-of-hospital cardiac arrest population. Resuscitation 2013;84:957–63. 7. Adielsson A, Hollenberg J, Karlsson T, et al. Increase in survival and bystander CPR in out-of-hospital shockable arrhythmia: bystander CPR and female gender are predictors of improved outcome. Experiences from Sweden in an 18-year perspective. Heart 2011;97:1391–6. 8. Weisfeldt ML, Sitlani CM, Ornato JP, et al. Survival after application of automatic external defibrillators before arrival of the emergency medical system: evaluation in the resuscitation outcomes consortium population of 21 million. J Am Coll Cardiol 2010;55:1713–20. 9. Noordergraaf GJ, Van Gerlder JME, Van Kesteren RG, Diets RF, Savelkoul TJF. Learning cardiopulmonary resuscitation skills: does the type of mannequin make a difference? Eur J Emerg Med 1997;4:204–9. 10. Mosesso VN, Shapiro AH, Stein K, Burkett K, Wang H. Effects of AED device features on performance by untrained laypersons. Resuscitation 2009;80:1285–9. 11. Kobayashi L, Lindquist DG, Jenouri IM, et al. Comparison of sudden cardiac arrest resuscitation performance data obtained from in-hospital incident chart review and in situ high-fidelity medical simulation. Resuscitation 2010;81:463–71.
12. Grenvik A, Schaefer J. From Resusci-Anne to Sim-Man: the evolution of simulators in medicine. Crit Care Med 2004;32:S56–7. 13. Wilson M, Shepherd I, Kelly C, Pitzner J. Assessment of a low-fidelity human patient simulator for the acquisition of nursing skills. Nurse Educ Today 2005;25:56–67. 14. McKenna L, Bogossian F, Hall H, et al. Is simulation a substitute for real life clinical experience in midwifery? A qualitative examination of perceptions of educational leaders. Nurse Educ Today 2011;31:682–6. 15. Beckers S, Fries M, Bickenbach J, et al. Minimal instructions improve the performance of laypersons in the use of semiautomatic and automatic external defibrillators. Crit Care 2005;9:R110–6. 16. Caird JK, Percival NB. Layperson and nurse performance using two automated Q6 external defibrillators. Int Conf Healthc Syst Ergon Pat Saf 2011:4–6. 17. Cohen J. A power primer. Psychol Bull 1992;112:155–9. 18. Brennan BT, Braslow A, Batcheller AM, Kaye W. A reliable and valid method for evaluating cardiopulmonary resuscitation training outcomes. Resuscitation 1996;85:85–93. 19. Diószeghy C, Kiss D, Fritúz G, Székely G, Élö G. Comparison of effects of different hand positions during cardiopulmonary resuscitation. Resuscitation 2005;66:297–301. 20. Percival NB, Pearson A, Jones J, Wilkins M, Caird JK. Ease of use of automated external defibrillators (AEDs) by older adults. Proc Hum Factors Ergon Soc Ann Meet 2012;56:906–10. 21. Merrigan O. Are there any cultural barriers to automated external defibrillators use in Middle Eastern countries? Circulation 2011;124:A229. 22. Lee F, Defibrillation. Singapore Med J 2011;52:544–7. 23. Hippocrates. The Oath The Internet Classics Archive. Available at: http://classics.mit.edu/Hippocrates/hippooath.html (accessed 7 October Q7 2014). 24. Meaney PA, Bobrow BJ, Mancini ME, et al. Cardiopulmonary resuscitation quality: improving cardiac resuscitation outcomes both inside and outside the hospital: a consensus statement from the American Heart Association. Circulation 2013;128:417–35. 25. Mortensen RB, Høyer CB, Pedersen MK, Brindley PG, Nielsen JC. Comparison of the quality of chest compressions on a dressed versus an undressed manikin: a controlled, randomised, cross-over simulation study. Scand J Trauma Resusc Emerg Med 2010;18:16. 26. Chavez DE, Meichke H, Painter I, Rea TD. Should dispatchers instruct lay bystanders to undress patients before performing CPR? A randomized simulation study. Resuscitation 2013;84:979–81. 27. Deakin CD, Nolan JP. European Resuscitation Council Guidelines for Resuscitation 2005. Section 3. Electrical therapies. Automated external defibrillators, defibrillation, cardioversion and pacing. Resuscitation 2005;67: S25–37. 28. Sundquist AB. Cooper’s droop: mystique of the bra-less mamma maligned. JAMA 1972;219:625. 29. Chieffo A, Hoye A, Mauri F, et al. R on be half of the WIN group Gender-based issues in interventional cardiology: a consensus statement from the Women in Innovations (WIN) initiative. Rev Esp Cardiol 2010;63:200–8.
Please cite this article in press as: Kramer CE, et al. Does the sex of a simulated patient affect CPR? Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2014.10.016
408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456
ARTICLE IN PRESS
RESUS 6177 1–6
Resuscitation xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
1
Clinical paper
2
Does the sex of a simulated patient affect CPR?夽
3
Q1
4 5 6 7 8
Q2
Chelsea E. Kramer a,c , Matthew S. Wilkins b,c , Jan M. Davies b,c,d , Jeff K. Caird b,c,∗ , Gregory M. Hallihan c a
Department of Psychology, Laval University, Laval, QC, Canada Department of Psychology, University of Calgary, Calgary, AB, Canada Healthcare Human Factors and Simulation Laboratory, W21 C Research and Innovation Centre, University of Calgary, Calgary, AB, Canada d Department of Anesthesia, Faculty of Medicine, University of Calgary, Calgary, AB, Canada b c
9
10 24
a r t i c l e
i n f o
a b s t r a c t
11 12 13 14 15
Article history: Received 24 June 2014 Received in revised form 10 October 2014 Accepted 19 October 2014
16
23
Keywords: Sex differences Cardiopulonary resuscitation (CPR) Automated external defibrillators (AEDs) Bystander resuscitation Experimental research Patient simulation
25
1. Introduction
17 18 19 20 21 22
26 27 28 29 30 31 32 33 34
Introduction: While males and females are equally at risk of sudden cardiac arrest (SCA), females are less likely to be resuscitated. Cardiopulmonary Resuscitation (CPR) may be inhibited by socio-cultural norms about exposing female victims’ chests. Empirically confirming this hypothesis is limited by lack of patient simulators modeling realistic female physiques. A commercially-available patient simulator was transformed to evaluate how physical attributes of a patient’s sex might influence lay participants who were asked to resuscitate a female versus a male during simulated cardiac arrest. Methods: Sixty-nine participants consented to be in the study. Participants were randomly assigned to provide CPR and defibrillation as instructed by a commercially-available automated external defibrillator on a patient simulator presented as either a male or female experiencing cardiac arrest. Results: Rescuers removed significantly more clothing from the male than the female, with men removing less clothing from the female. More rescuers’ initial hand placements for CPR were centered between the female’s breasts compared to the male, on which placement was distributed across the chest towards the nipples. Discussion: While rescuers had better hand placement for CPR on the female, both men and women rescuers were reluctant to remove the female’s clothing, with men significantly more hesitant. Reticence to remove clothing was often articulated relative to social norms during structured interviews. We suggest that using only male simulators will not allow trainees to experience social differences associated with the care of a female simulated patient. Realistic female patient simulators are needed. © 2014 Elsevier Ireland Ltd. All rights reserved.
Early Cardiopulmonary Resuscitation (CPR) is a key link in the resuscitation “chain of survival” for Sudden cardiac arrest (SCA).1 While female sex increases the probability of survival to hospital from out-of-hospital cardiac arrest (OHCA) after bystander or formal resuscitation,2–7 women are less likely to receive such care from both lay2,5–7 and medically-trained personnel.5,8 However, reasons for this difference are either not discussed2,8 or only suggested but not supported by data.5,6 For example, Ahn and colleagues postulated that cultural reasons contributed to not
夽 A Spanish translated version of the abstract of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2014.10.016. Q3 ∗ Corresponding author at: Department of Psychology, University of Calgary, 2500 University Dr. N. W. Calgary, Alberta, Canada T2N1N4. E-mail address: [email protected] (J.K. Caird).
removing clothing from females’ upper chests in an out-of-hospital setting.5 To our knowledge no studies support or refute the conjecture that ‘sex matters’. Typically, CPR training and research tend to use one type of simulator, either torso mannequins (Laerdal’s Little Anne® )9 or full body mannequins (SimMan® ).10,11 Although medical simulators are considered “realistic models of real patients”12 and educationally useful,13 they have been described as having “perceived low levels of realism”.14 This comment was made in reference to simulation’s utility in midwifery education, but could also be applied to female patients. We therefore questioned the assumption that current patient simulators are sufficient both to train and to understand the behavior of caregivers with respect to male and female patients. We hypothesized that physical attributes of a patient’s sex might influence lay participants when resuscitating a female versus male victim during simulated cardiac arrest. For example, an undergarment (e.g., a brassiere) would require direct garment manipulation
http://dx.doi.org/10.1016/j.resuscitation.2014.10.016 0300-9572/© 2014 Elsevier Ireland Ltd. All rights reserved.
Please cite this article in press as: Kramer CE, et al. Does the sex of a simulated patient affect CPR? Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2014.10.016
35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
G Model RESUS 6177 1–6
ARTICLE IN PRESS C.E. Kramer et al. / Resuscitation xxx (2014) xxx–xxx
2
60
(e.g., unclasping or cutting) to ensure the rescuer “remove[s] all clothing from [the] patient’s chest”15 (as instructed by an automated external defibrillator (AED)) before successful defibrillation. We postulated such considerations, as well as social factors, could hinder complete clothing removal from a female simulated patient, as well as determine where on the chest rescuers initially placed their hands to perform CPR. Our primary outcome measures were percentage of clothing removed and placement of rescuers hands.
61
2. Method
62
2.1. Participants
53 54 55 56 57 58 59
76
The University of Calgary’s Biomedical Ethics Committee certified the study and 69 undergraduate students volunteered through the University’s research participation system. Participants received one course credit in exchange for participation. Participants were screened for English fluency and near visual acuity (to 40 cm), which approximated the distance required for AED interaction. The total number of participants recruited was based on a previous AED study16 and effect size estimates.17 Participants were quasi-randomly assigned to either the male or female simulator depending on the timing of participant sign-up, the time required to make the sex change of the patient simulator and the necessity to equilibrate men and women in each simulator group. Participants were not given any information about the nature of the study except that AED use was being examined.
77
2.2. Equipment and setting
63 64 65 66 67 68 69 70 71 72 73 74 75
95
Patient Simulator. A commercially available patient simulator (METI iStan® ) was used in the control condition (Fig. 1, left). iStan was modified to represent a female victim in the experimental condition (iSamantha or ‘iSam’; Fig. 1, right). Transformation from male to female involved use of a wig, make-up, silicone breasts, a front-opening brassiere and color-coordinated women’s clothing. AED. Participants performed all simulation OHCA scenarios using a Medtronic LifePak CR® + AED (training version). Simulation Laboratory. The study was conducted in the Healthcare Human Factors and Simulation Laboratory (HHFSL) at the W21 C Research and Innovation Centre at the University of Calgary (www.w21c.org). The HHFSL has simulation and control rooms. The former contains four directional microphones and four ceiling mounted cameras with pan, tilt and zoom capabilities to record participant, AED and patient simulator interactions. Participants were also observed in real-time through a one-way window from the control room containing observational and analytical hardware and software systems.
96
2.3. Procedure
78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94
97 98 99 100 101 102 103 104 105 106 107 108 109 110 111
Upon arrival, participants gave informed consent, provided demographic information and were introduced to the simulator room containing the male or female patient simulator. Each participant was oriented to the patient simulator and how it functioned. Participants were told they would be rescuing an unconscious patient from cardiac arrest. Once they understood what they would be doing during the study they exited the simulator room with the experimenter. The OHCA scenario began when the experimenter and participant re-entered the room to find either iStan or iSam on the floor in an apparent state of arrest. Each participant was given an AED and a barrier mask for rescue breaths. No instructions on CPR or the use of the AED were provided. The experimenter left the room under the pretense of going “to go call an ambulance”. Participants had to work through the operation of the AED on their own. Once
activated, the AED provided verbal commands to guide participants through each of five steps: (1) open case; (2) activate AED; (3) position electrode pads; (4) deliver shock; and (5) administer CPR. The AED was programmed to deliver two shocks. The first shock was always unsuccessful so the rescuer had to perform CPR. The AED instructed the participant to “provide chest compressions and rescue breaths”. To avoid undue psychological distress, delivery of the second shock was always followed by programmed recovery of the simulated patient, regardless of the individual’s performance with the AED. When the OHCA scenario was over, participants underwent a structured interview about their experience, including an understanding of removal of the patient’s clothing, their reservations (if any) in doing so, their potential degree of comfort in resuscitating a patient and perceptions about the patient. Participants were also debriefed on proper AED technique and given information about available CPR training courses. The entire study took approximately 45 min for each participant to complete. 2.4. Experimental design and statistical analysis The video and audio from the OHCA scenario were recorded by Noldus Media Recorder, coded with Noldus Observer® XT (v. 9.0) and analyzed using IBM SPSS® (v. 19). Chi-square tests and MannWhitney U tests were used to test primary outcome measures in the experimental design of simulated patient sex (male vs. female) and rescuer sex (men vs. women). Specifically, the primary outcome measures (POM) were: (1) the percentage of rescuers who completely removed clothing from the simulated female patient’s chest compared to the simulated male’s and (2) the placement (position, orientation and classification) of rescuers’ hands when CPR was initiated. The first POM was determined by viewing the video images. Clothing removal was scored as complete or incomplete. To determine the second POM, photographs of iStan’s and iSam’s chests were taken from the same perspective (frontal view) and location to ensure identical sizes of and proportions between the two images (error = ±4 pixel). The clavicles, sternal notch, nipples, xiphisternum and distal rib cage served as anatomical landmarks. A single coder used these landmarks and multiple camera angles/video images to select an image best showing initial placement of each rescuer’s hands. For hand position and orientation, a researcher reviewed the recorded participant data. Based on initial hand placement at the onset of CPR, each rescuer’s left and right hands were plotted on a schematic of iStan or iSam’s chest, starting from the base of the palm to the longest point of the middle finger. If the hand was curled, the length was marked as the most distal knuckle. Each hand was thus represented as a line from palm to (usually) the middle finger on iStan’s or iSam’s chest. In addition, the mid-point of the distal (i.e., base) palm of the lower hand was determined (as the distal central point of pressure) and marked as a dot on the line. Each (hand) line was compared to two lines on the simulator’s body: a nipple-nipple line (x-axis) and a cephalad-caudad line through the body’ midline (y-axis). This comparison thus showed position and orientation of the hands to these lines on the simulated patient’s chest. For hand placement classification, two concepts were used, one of which was established CPR guidelines.18 The other was that of “correct position, incorrect position and dangerous areas” for safe and effective CPR, described by Diószeghy and colleagues.19 We superimposed their diagram of the anterior chest showing three corresponding rectangular areas–‘green’ (“correct”), ‘yellow’ (“incorrect”) or ‘red’ (“dangerous”) zones for CPR [19]–onto a video
Please cite this article in press as: Kramer CE, et al. Does the sex of a simulated patient affect CPR? Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2014.10.016
112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129
130
131 132 133 134 135 136 137
138 139 140 141 142
143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173
G Model
ARTICLE IN PRESS
RESUS 6177 1–6
C.E. Kramer et al. / Resuscitation xxx (2014) xxx–xxx
3
Fig. 1. Male iStan (left), and female iSam (right).
179
image of each rescuer’s initial hand position. Distal hand positions within the ‘green/yellow’ and within/outside the ‘red’ zone were counted for both iStan and iSam. Participants who did not attempt chest compressions (n = 2) or separated their hands rather than placing one on top of the other (n = 9) were excluded from this analysis.
responders who completely removed clothing also differed significantly between rescuer sex for iSam, X2 (1, 33) = 9.53 p = 0.002). Men rescuers (n = 2/15 removed or 13.3%) were significantly less likely to completely de-robe iSam than were women rescuers (n = 12/18 removed or 66.7%). There was no difference between men and women in de-robing iStan.
180
3. Results
3.3. Hand placement
181
3.1. Participant characteristics
Fig. 3 shows both hands of participants on iStan (left) and iSam (right). Lines represent initial hand placements from the base of the palm to the longest point of the middle finger, with dots indicating the center of the distal palm. Men rescuers are represented as blue and women as pink lines in the color images, respectively. Placement of participants’ hands on the chest differed if the simulated patient was male or female. Participants who performed CPR on iStan showed more variability in hand placement over a greater area of the chest (Fig. 3, left). Placement of hands on iSam tended to be centered between the breasts (see Fig. 3, right). The location of participants’ hands with respect to the green, yellow and red zones is shown in Fig. 4. A Chi-square test of hand placement in green/yellow and ‘red’ zones was significant X2 (1, 57) = 4.3, p < .039 (see Fig. 5). Initial hand placement on iStan was significantly less accurate than on iSam. Within the iSam group, a greater proportion of participants placed their hands within the green/yellow zones (48.4%) than with iStan (22.2%).
174 175 176 177 178
186
Table 1 shows the characteristics of our sample of participants. An approximately equal number of men and women of similar ages and CPR/AED training were in either the iStan or iSam groups. There were no group differences for either AED or CPR training (see Table 1).
187
3.2. Clothing removal
182 183 184 185
188 189 190 191 192 193 194
A Chi-square test was performed to test the relationship between patient sex (male vs. female) and rescuer sex (men vs. women). Fig. 2 shows that the proportion of rescuers who completely removed a patient’s clothing differed significantly between patient simulators X2 (1, 69) = 19.22, p < 0.001. Rescuers were more likely to completely bare iStan’s chest (n = 33/36 removed or 91.7%) compared to iSam’s (n = 14/33 removed or 42.4%). The percent of
80 60 Complete clothing removal (%)
Men Rescuers Women Rescuers
40 20 0 Male Patient
Female Patient
Patient Simulator Fig. 2. Percent of men and women rescuers who completely removed clothing from chest of male and female patient simulators.
197 198 199 200
202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218
219
The purpose of this study was to determine if CPR for an OHCA scenario was performed differently for a simulated male versus female patient. Sixty-nine lay participants were quasi-randomly assigned to a male or female patient simulator and asked to resuscitate the simulated patient with AED guided CPR. We found performance of specific CPR steps was influenced by the apparent sex of the simulator and the sex of the participants, who had been blinded to the purpose of the study. Removal of clothing. Both men and women rescuers were reluctant to remove iSam’s clothing (see Fig. 2). Only 42% (n = 14) of all participants removed both iSam’s blouse and brassiere. In comparison, previous studies with the same simulated male patient showed all participants completely bared iStan’s chest.16,20
Table 1 Study participant demographics and experience.
Mean age (SD) Sex AED experience CPR training within the last 5 years
196
201
4. Discussion
100
195
Male patient simulator (N = 36)
Female patient simulator (N = 33)
Significance
21.8 (5.2) 16 Male, 20 female 9 (25.0%) 11 (30.6%)
24.0 (8.4) 15 Male, 18 female 5 (15.1%) 11 (33.3%)
NS (p = 0.21) NS (p = 0.93) NS (p = 0.34) NS (p = 0.74)
Please cite this article in press as: Kramer CE, et al. Does the sex of a simulated patient affect CPR? Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2014.10.016
220 221 222 223 224 225 226 227 228 229 230 231 232
G Model RESUS 6177 1–6 4
ARTICLE IN PRESS C.E. Kramer et al. / Resuscitation xxx (2014) xxx–xxx
Fig. 3. Initial placement for CPR of both hands on male (left) and female (right) simulators. Dots show the center of the palm of the bottom hand and lines represent the length of the longest extended finger. Blue lines represent male rescuers and pink lines represent female rescuer. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
233 234 235 236 237 238 239 240 241 242 243 244 245 246 247
Men were significantly more hesitant than women to remove iSam’s clothing. Only two men removed the brassiere. When interviewed about their decisions not to do so, participants most often responded they thought they needed only to remove enough clothing to place the defibrillator pads according to instructions rather than ensuring the brassiere would not affect CPR. During interviews, reticence to remove clothing was often articulated relative to social norms. Apparently concerned for patient modesty, men did not want to remove more clothing than necessary. Of note, we chose to use a front-opening brassiere because of the simulator’s weight and not wanting participants to cut the brassiere. Our results therefore might underestimate the real life difficulties of removing a back-opening brassiere. Our study with a simulated female patient suggests clear AED instructions about clothing removal from a female patient’s chest
could affect CPR performance for a female patient. Our results are consistent with other research.21 Merrigan had participants rate photographed vignettes of a (simulated) male or female victim in cardiac arrest with photographs of a man or woman rescuer of three different ethnic groups (European, Indian Sub-Continent and Arab). Participants (n = 345) expressed lower acceptability ratings for Indian men to rescue female patients, but no differences were found for the ethnicities of other men.21 The results of Merrigan’s study and ours suggest that female victims of OHCA may be less likely to be resuscitated due to cultural taboos of exposing a female’s breasts in public. Further support for this suggestion comes from two publications. In one, female patients were less likely than males to receive CPR from “policemen”.2 In another, the statement was made that when resuscitating a female patient in public, “chest exposure
Fig. 4. Locations of hand placement for CPR superimposed on male (left) and female (right) patient simulators. Dots show the center of the palm of the bottom hand and lines represent the length of the longest extended finger. Blue lines represent male rescuers and pink lines represent female rescuers. Participants whose hands did not overlap (n = 9) were excluded from this analysis. [Anatomic and zone overlay reprinted from Diószeghy et al. Comparison of effects of different hand positions during cardiopulmonary resuscitation. Resuscitation 2005; 66: 297–301, with permission from Elsevier.]. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
Please cite this article in press as: Kramer CE, et al. Does the sex of a simulated patient affect CPR? Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2014.10.016
248 249 250 251 252 253 254 255 256 257 258 259 260 261 262
G Model
ARTICLE IN PRESS
RESUS 6177 1–6
C.E. Kramer et al. / Resuscitation xxx (2014) xxx–xxx 25
4.1. Limitations and future research
20
Although the artificial breasts used were somewhat realistic, their appearance was more representative of those of a younger woman and not those of someone older who might have breasts with “Cooper’s droop”.28 This limitation is important because it was difficult to match iSam’s physical characteristics with those of iStan (used in previous studies). During post-study interviews, participants suggested iStan was about 33 years old, while iSam appeared older—about 45 years. iStan’s suggested age corresponds to the fact his original design was based on a real 30-year old man. iSam appeared older, partly because of her large-sized clothing and her bulky (simulator) body. In addition, the mannequin’s heavy-set facial features, even with carefully applied wig and make-up, gave the impression of a more ‘mature’ woman. It is possible that some participants’ perception of iSam’s age could have subtly affected their willingness to intervene in a realistic manner with a simulated OHCA victim. In fact, many participants stated “old age” was a potentially inhibiting factor in their willingness to perform CPR. It was difficult to find a sample of participants without any CPR training. Ten students reported receiving basic CPR in their high school curriculum, which for some also included exposure to AEDs. Nevertheless, many who reported some training in the past five years still failed to remove either patient’s clothes and/or demonstrated incorrect initial hand placement for CPR. The results of our study may actually be optimistic when extrapolating to the real world. Our participants were younger and had higher levels of education than would be expected of the general public, potentially contributing to an overly positive portrayal of iSam’s care. Members of the public might be more hesitant to disrobe an actual female patient. Furthermore, the effect of presence of others on a rescuer’s willingness to completely remove a female patient’s clothing from her chest is not known. During structured interviews, some of our participants stated having bystanders present might hinder them, while others said that bystanders would make them more comfortable. Such reticence is a complex matter, with personal, contextual and social contributors, including not wanting to be involved or to touch bare skin, in addition to cultural reasons.26 While there are many questions to be addressed by future research, we suggest the most important question is: How do we determine the most effective way to overcome societal and cultural inhibitions so that we can provide better care for female patients? As we already know, improving care for women with cardiovascular disease is a fundamental principle.29
15
Male Simulator
Number of Participants
Female Simulator
10
5
0
Inside Yellow/Green Zones
Inside or Outside Red Zone
Initial Hand Placement Fig. 5. Frequency of initial hand placement (bottom hand) within the ‘green/yellow’ zones and inside or outside the ‘red’ zone on male and female patient simulators. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306
5
should be limited to the area where the defibrillation pads are applied, after which the chest wall may be covered by the patient’s own clothing”.22 Part of the author’s explanation for this was “to give due respect to women”.22 Having respect for all patients, regardless of their sex, is central to the practice of medicine, as espoused in the Hippocratic Oath.23 While re-covering a woman’s “chest wall” with her own clothing could be seen as implying a particular type of “respect for women”, the act of replacing clothing and the presence of the clothing could also impede resuscitative efforts. As Meaney and colleagues emphasized, the inherent inefficiency of CPR “highlights the need for trained rescuers to deliver the highest-quality CPR possible”, including a “standardized approach”.24 Mortensen and colleagues compared the quality of chest compressions on a dressed versus undressed mannequin and found no significant differences in CPR.25 Chavez and colleagues demonstrated compression depth, rate and release were no worse when a mannequin’s clothing was not removed.26 However, Mortensen et al. commented that rescuers might have “no option but to occasionally unclothe the thorax” to apply AED pads.25 Similarly, Chavez and colleagues stated clothing would have to be removed to apply AED pads.26 Thus, for AED-guided CPR, removal of clothing would remain third on the list of instructions. Hand placement. Clinically, initial hand placement is important. However, a number of participants did not know where to position their hands when performing compressions, as shown by hand placement outside the ‘red’ zone of the chest. Chest compressions in these areas could result in harm.19 These incorrect hand placements are likely representative of lay rescuers who had not received CPR instruction immediately before testing. Guidance as to where rescuers should place their hands could be improved by instructor feedback27 and clear AED verbal/pictorial instructions. On iStan, hand placement tended to be distributed across the chest (see Fig. 3, left). In contrast, on iSam, rescuers’ hands were more centralized over the sternum—and not generally over the breasts. We were unable to determine if rescuers attempted to avoid touching iSam’s breasts or if these ‘landmarks’ aided the lay rescuers in choosing better hand placement. In addition, although we did not measure CPR effectiveness, the better hand placement on iSam’s chest could have resulted in improved CPR. Nevertheless, social norms appeared to constrain both clothing removal and hand placement for CPR on the female simulator. This was an unexpected finding.
5. Conclusion We hypothesized that physical attributes of a patient’s sex might influence lay participants when resuscitating a female versus male during simulated cardiac arrest. Our results suggest that the sex of a simulated patient does affect CPR, with participants being more reluctant to remove clothing from the female compared to the male simulated patient. Rescuers were more likely to centre their hands between the female’s breasts than with the male, on which hand placement was distributed across the chest towards the nipples. Our results suggest individuals may interact differently with females than males when responding to OHCA. The absence of realistic female patient simulators may bias training for and research into patient care.
Conflict of interest statement The authors have none.
Please cite this article in press as: Kramer CE, et al. Does the sex of a simulated patient affect CPR? Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2014.10.016
307
308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350
351
352 353 354 355 356 357 358 359 360 361 362 363
364
365
G Model RESUS 6177 1–6
C.E. Kramer et al. / Resuscitation xxx (2014) xxx–xxx
6 366
ARTICLE IN PRESS
Acknowledgments
We thank Ruth Diaz, Jessica Jones, Aimee Pearson, Nicole Percival, and Elise Teteris for assistance. This research was facilitated 368 Q4 through generous support of the Calgary Health Trust, the National 369 Q5 Science and Engineering Research Council and W21 C, the latter 370 funded by a Western Economic Development grant that paid for 371 the study’s capital equipment. 372 367
373
374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407
References 1. Cummins RO, Ornato JP, Thies WH, Pepe PE. Improving survival from sudden cardiac arrest: the “Chain of Survival” concept. A statement for health professionals from the Advanced Cardiac Life Support Subcommittee and the Emergency Cardiac Care Committee American Heart Association Writing Group. Circulation 1991;83:1832–47. 2. Herlitz J, Engdahl J, Svensson L, et al. Is female sex associated with increased survival after out-of-hospital cardiac arrest? Resuscitation 2004;60:197–203. 3. Mahapatra S, Bunch TJ, White RD, Hodge DO, Packer DL. Sex differences in outcome after ventricular fibrillation in out-of-hospital cardiac arrest. Resuscitation 2005;65:197–202. 4. Teodorescu C, Reinier K, Uy-Evanado A, et al. Survival advantage from ventricular fibrillation and pulseless electrical activity in women compared to men: the Oregon Sudden Unexpected Death Study. J Interv Card Electrophysiol 2012;34:219–25. 5. Ahn KO, Shin Do S, Hwang SS. Sex disparity in resuscitation efforts and outcomes in out-of-hospital cardiac arrest. Am J Emerg Med 2012;30:1810–6. 6. Bray JE, Stub D, Bernard S, Smith K. Exploring gender differences and the “oestrogen effect” in an Australian out-of-hospital cardiac arrest population. Resuscitation 2013;84:957–63. 7. Adielsson A, Hollenberg J, Karlsson T, et al. Increase in survival and bystander CPR in out-of-hospital shockable arrhythmia: bystander CPR and female gender are predictors of improved outcome. Experiences from Sweden in an 18-year perspective. Heart 2011;97:1391–6. 8. Weisfeldt ML, Sitlani CM, Ornato JP, et al. Survival after application of automatic external defibrillators before arrival of the emergency medical system: evaluation in the resuscitation outcomes consortium population of 21 million. J Am Coll Cardiol 2010;55:1713–20. 9. Noordergraaf GJ, Van Gerlder JME, Van Kesteren RG, Diets RF, Savelkoul TJF. Learning cardiopulmonary resuscitation skills: does the type of mannequin make a difference? Eur J Emerg Med 1997;4:204–9. 10. Mosesso VN, Shapiro AH, Stein K, Burkett K, Wang H. Effects of AED device features on performance by untrained laypersons. Resuscitation 2009;80:1285–9. 11. Kobayashi L, Lindquist DG, Jenouri IM, et al. Comparison of sudden cardiac arrest resuscitation performance data obtained from in-hospital incident chart review and in situ high-fidelity medical simulation. Resuscitation 2010;81:463–71.
12. Grenvik A, Schaefer J. From Resusci-Anne to Sim-Man: the evolution of simulators in medicine. Crit Care Med 2004;32:S56–7. 13. Wilson M, Shepherd I, Kelly C, Pitzner J. Assessment of a low-fidelity human patient simulator for the acquisition of nursing skills. Nurse Educ Today 2005;25:56–67. 14. McKenna L, Bogossian F, Hall H, et al. Is simulation a substitute for real life clinical experience in midwifery? A qualitative examination of perceptions of educational leaders. Nurse Educ Today 2011;31:682–6. 15. Beckers S, Fries M, Bickenbach J, et al. Minimal instructions improve the performance of laypersons in the use of semiautomatic and automatic external defibrillators. Crit Care 2005;9:R110–6. 16. Caird JK, Percival NB. Layperson and nurse performance using two automated Q6 external defibrillators. Int Conf Healthc Syst Ergon Pat Saf 2011:4–6. 17. Cohen J. A power primer. Psychol Bull 1992;112:155–9. 18. Brennan BT, Braslow A, Batcheller AM, Kaye W. A reliable and valid method for evaluating cardiopulmonary resuscitation training outcomes. Resuscitation 1996;85:85–93. 19. Diószeghy C, Kiss D, Fritúz G, Székely G, Élö G. Comparison of effects of different hand positions during cardiopulmonary resuscitation. Resuscitation 2005;66:297–301. 20. Percival NB, Pearson A, Jones J, Wilkins M, Caird JK. Ease of use of automated external defibrillators (AEDs) by older adults. Proc Hum Factors Ergon Soc Ann Meet 2012;56:906–10. 21. Merrigan O. Are there any cultural barriers to automated external defibrillators use in Middle Eastern countries? Circulation 2011;124:A229. 22. Lee F, Defibrillation. Singapore Med J 2011;52:544–7. 23. Hippocrates. The Oath The Internet Classics Archive. Available at: http://classics.mit.edu/Hippocrates/hippooath.html (accessed 7 October Q7 2014). 24. Meaney PA, Bobrow BJ, Mancini ME, et al. Cardiopulmonary resuscitation quality: improving cardiac resuscitation outcomes both inside and outside the hospital: a consensus statement from the American Heart Association. Circulation 2013;128:417–35. 25. Mortensen RB, Høyer CB, Pedersen MK, Brindley PG, Nielsen JC. Comparison of the quality of chest compressions on a dressed versus an undressed manikin: a controlled, randomised, cross-over simulation study. Scand J Trauma Resusc Emerg Med 2010;18:16. 26. Chavez DE, Meichke H, Painter I, Rea TD. Should dispatchers instruct lay bystanders to undress patients before performing CPR? A randomized simulation study. Resuscitation 2013;84:979–81. 27. Deakin CD, Nolan JP. European Resuscitation Council Guidelines for Resuscitation 2005. Section 3. Electrical therapies. Automated external defibrillators, defibrillation, cardioversion and pacing. Resuscitation 2005;67: S25–37. 28. Sundquist AB. Cooper’s droop: mystique of the bra-less mamma maligned. JAMA 1972;219:625. 29. Chieffo A, Hoye A, Mauri F, et al. R on be half of the WIN group Gender-based issues in interventional cardiology: a consensus statement from the Women in Innovations (WIN) initiative. Rev Esp Cardiol 2010;63:200–8.
Please cite this article in press as: Kramer CE, et al. Does the sex of a simulated patient affect CPR? Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2014.10.016
408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456
