Controlled Breathing With or Without Peppermint Aromatherapy for Postoperative Nausea and/or Vomiting Symptom Relief: A Randomized Controlled Trial Debra S. Sites, MHA, BSN, RN, Nancy T. Johnson, BSN, RN, Jacqueline A. Miller, MSN, RN, NE-BC, Pauline H. Torbush, RN, CAPA, Janis S. Hardin, BSN, RN, CPAN, Susan S. Knowles, MSN, RN-BC, Jennifer Nance, BSN, RN, Tara H. Fox, MSN, CRNA, Rebecca Creech Tart, PhD Purpose: With little scientific evidence to support use of aromatherapy for postoperative nausea and/or vomiting (PONV) symptoms, this study evaluated controlled breathing with peppermint aromatherapy (AR) and controllled breathing alone (CB) for PONV relief. Design: A single blind randomized control trial design was used. Methods: On initial PONV complaint, symptomatic subjects received either CB (n 5 16) or AR (n 5 26) intervention based on randomization at enrollment. A second treatment was repeated at 5 minutes if indicated. Final assessment occurred 10 minutes post initial treatment. Rescue medication was offered for persistent symptoms. Findings: Among eligible subjects, PONV incidence was 21.4% (42/ 196). Gender was the only risk factor contributing to PONV symptoms (P 5 .0024). Though not statistically significant, CB was more efficacious than AR, 62.5% versus 57.7%, respectively. Conclusions: CB can be initiated without delay as an alternative to prescribed antiemetics. Data also support use of peppermint AR in conjunction with CB for PONV relief.
Keywords: aromatherapy, postoperative nausea and/or vomiting, controlled breathing, peppermint. Ó 2014 by American Society of PeriAnesthesia Nurses ONE OF THE MOST COMMON FEARS patients express when facing surgery is postoperative nausea and/or vomiting (PONV), which ranges
from minor queasiness to protracted periods of vomiting. It remains one of the most predictable indicators of prolonged postoperative stays,
Debra S. Sites, MHA, BSN, RN, is a Day Surgery Staff Nurse, Catawba Valley Medical Center, Hickory, NC; Nancy T. Johnson, BSN, RN, formerly was a Day Surgery Staff Nurse, Catawba Valley Medical Center, Hickory, NC; Jacqueline A. Miller, MSN, RN, NE-BC, is a Director for Day Surgery/PACU, Catawba Valley Medical Center, Hickory, NC; Pauline H. Torbush, RN, CAPA, is a Day Surgery Staff Nurse, Catawba Valley Medical Center, Hickory, NC; Janis S. Hardin, BSN, RN, CPAN, is a PACU Staff Nurse, Catawba Valley Medical Center, Hickory, NC; Susan S. Knowles, MSN, RN-BC, is a Clinical Nurse Manager, Gaston Memorial Hospital, Gastonia, NC; Jennifer Nance, BSN, RN, is Director of Alexander County Home Health, Alexander County Home Health, Taylorsville, NC; Tara H. Fox, MSN, CRNA, is a Staff Nurse Anesthetist, Catawba
Valley Medical Center, Hickory, NC; and Rebecca Creech Tart, PhD, is the Director for Research and Evidence-Based Practice, Catawba Valley Medical Center, Hickory, NC.
The Magnet Recognition Program is a registered trademark of the American Nurses Credentialing Center, Silver Spring, MD. Conflict of interest: None to report. Address correspondence to Debra S. Sites, Catawba Valley Medical Center, 810 Fairgrove Church Rd SE, Hickory, NC 28602; e-mail address: [email protected]
Ó 2014 by American Society of PeriAnesthesia Nurses 1089-9472/$36.00 http://dx.doi.org/10.1016/j.jopan.2013.09.008
Journal of PeriAnesthesia Nursing, Vol 29, No 1 (February), 2014: pp 12-19
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unplanned admissions and delayed return to activities of daily living and employment.1 A number of negative outcomes are associated with vomiting, including pulmonary aspiration, suture dehiscence, esophageal rupture, subcutaneous emphysema, and bilateral pneumothoraces.2,3 PONV complications cost health care insurers and providers millions of dollars a year. PONV occurs in approximately one third of the 75 million patients who undergo surgery annually.2 Among patients deemed high-risk because of predisposing factors such as a history of motion sickness, the incidence of PONV can be as high as 70% to 80%.1 History of migraines, female gender, and type and duration of surgery are also noted to be important predictors of PONV.3 Many times, health care providers turn first to medications when patients complain of nausea and vomiting. However, there are potentially adverse side effects associated with antiemetics, such as sedation, alterations in blood pressure, and electrocardiographic changes.2,4,5 Furthermore, the cost of medications directly affects not only these patients but the health care industry as well. Aromatherapy dates back thousands of years to the ancient cultures of Egypt and India.6 Although it is one of the lesser-known alternative therapies in the United States, nonconventional therapies are commonly practiced in Germany, France, Australia, Finland, Canada, and the United Kingdom.7 The American Society of PeriAnesthesia Nurses (ASPAN) Evidence-Based Clinical Practice Guideline for the Prevention and/or Treatment of PONV and Post Discharge Nausea and Vomiting (PDNV) in Adult Patients recommends implementation of rescue interventions to include aromatherapy during both Phase I and Phase II postanesthesia care.1 Maddocks-Jennings and Wilkinson8 noted in an integrative literature review that aromatherapy has also been used in the treatment of cancer patients, obstetric patients, and for patients experiencing gastric distress. More recently, oncology nurses have researched orange aromatherapy for symptomatic treatment among patients receiving preserved stem cell infusions.9 Lane and colleagues10 evaluated nausea following C-section procedures where subjects were randomized to
one of three groups: peppermint spirits, placebo, or standard antiemetic treatment. They reported reduced nausea scores in the majority of subjects in the peppermint aromatherapy arm, whereas the postsurgical nausea scores of the other two groups remained high. Much information on aromatherapy can be found in lay publications. In the medical realm, however, most aromatherapy research is anecdotal. A limited number of scientifically sound studies addressing postoperative nausea and/or vomiting have been published. Furthermore, there are only a few research studies that have been conducted to evaluate the efficacy of inhaled peppermint in the treatment of PONV, and it has been suggested that peppermint aromatherapy requires further study.1,3 Tate11 studied the efficacy of peppermint oil (experimental) as a treatment for PONV versus peppermint essence (placebo) or no treatment (control) following gynecologic surgery. Neither subject assignment (N 5 18) to the groups nor the number of subjects in each group was addressed. Subjects were given unrestricted use of the same volume of peppermint oil without documenting the extent of its use among subjects. Despite these limitations, this study did suggest that peppermint oil might improve postoperative nausea in gynecological patients. Anderson and Gross12 sought to determine if peppermint oil, isopropyl alcohol (IPA), or a saline placebo decreased postoperative nausea. They found that the placebo was as effective as IPA or peppermint oil in reducing symptoms. Their results suggested that the benefit observed might be due to the consciously controlled breathing technique rather than the aroma inhaled. A study by Winston and colleagues,13 designed to evaluate ondansetron versus 70% IPA for the treatment of PONV, concluded that symptoms were resolved more readily with inhaled IPA. Furthermore, they evaluated the incidence of PONV up to 24 hours postoperatively by telephoning subjects. Their data revealed that subjects treated with IPA incurred a higher incidence of PONVafter discharge home than their counterparts who were treated with ondansetron. Likewise, a replication of the Winston et al study reported similar findings in 2007.14 The IPA group’s symptoms resolved faster
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than those of the ondansetron group as found previously. Both groups were discharged with promethazine suppositories to self-administer in the event they experienced PONV at home. In addition, alcohol pads were provided to IPA subjects. There was no significant difference in the incidence of PONV following discharge; however, five control subjects used promethazine for rescue compared to one experimental subject. The researchers recommended expanding the study population to include a wider variety of surgeries in future research.14 More recently, Pellegrini et al5 determined that the inhalation of IPA was as effective as promethazine in treating symptoms in high-risk PONV patients who received perioperative prophylactic ondansetron. The research sample size (N 5 85) was adequate for making this determination. To investigate prophylactic prevention of PONV, Teran and Hawkins15 compared isopropyl alcohol, granisetron, and no treatment. In tracking the number of minutes before PONV symptoms appeared postsurgery, there was no significant difference between the three groups at the first nausea and/or vomiting episode. Likewise, for subjects requiring antiemetic rescue, numerical rating scale scores did not differ significantly between the groups. Thus, IPA was not efficacious as a prophylactic antiemetic, nor was granisetron more effective than no treatment. Although perioperative day surgery nurses at this facility were using peppermint aromatherapy in their practice, this literature appraisal revealed that the evidence to support its use was weak. Further aromatherapy research was required to evaluate deep breathing alone, broadening risk factor and surgical procedure inclusion criteria, as well as titrating the amount of aromatherapy exposure. Therefore, a rigorous evaluation of their practice of using aromatherapy for PONV incidence was undertaken. Interestingly, a Cochrane systematic review on aromatherapy for the treatment of PONV was recently published.16 Of the six studies highlighted above forming the basis for this study, five met inclusion criteria for this 2012 systematic review.
Methods Study Design and Setting This single-blind, parallel-group, randomized controlled trial evaluated controlled breathing alone
versus peppermint aromatherapy combined with controlled breathing to alleviate PONV symptoms. The facility is a not-for-profit, Magnet hospital licensed for 258 beds that serves a rural community in the southeastern United States. The study was conducted from June 2010 to November 2011 in the facility’s 15-room operating suite, 12open-bay PACU, and 21-bed day surgery unit. The research protocol was developed using a multidisciplinary approach, which encompassed the overall perioperative course. The study was approved by the facility’s institutional review board (IRB). Sample Based on power analysis using data from published research,15 a sample of 130 total subjects was required for a power of 0.8 and a 5 0.05, with allowance for 40% attrition to include subjects with no PONV symptoms. Because of the low incidence of PONV among subjects in this study, a convenience sample was used when it was determined to be unrealistic to continue the study beyond 17 months. Eligible subjects were 18 years and older, male or female, of any ethnic background, ASA status I or II, able to breathe through their nose, capable of verbalizing occurrences of nausea and/or vomiting, scheduled for laparoscopic, ENT, orthopedic, or urological day surgery procedures undergoing general anesthesia with intubation. Exclusion criteria included nausea and/or vomiting within 24 hours of admission, history of alcoholism, allergy to menthol or peppermint, weekend or emergent surgeries, department of correction clients, pregnant women, patients taking disulfiram (Antabuse) or metronidazole (Flagyl), and minors. Study Protocol PREOPERATIVE PHASE. Day Surgery nurses recruited subjects, obtained written informed consent, documented PONV risk factors, and assessed baseline nausea and/or vomiting. Symptoms were assessed using a 0 to 10 descriptive ordinal scale (DOS) with 0 being none and 10 being the worst symptoms a subject could imagine. A computergenerated random number table was used to determine subject assignment to either the control (controlled breathing alone [CB]) or experimental (aromatherapy with controlled breathing [AR]) group.
AROMATHERAPY FOR PONV
INTRAOPERATIVE PHASE. Certified Registered Nurse Anesthetists (CRNAs) administered the anesthesia protocol. Subjects were given propofol (Diprivan or Propoven) for induction followed by either sevoflurane or desflurane as the inhalation agent. Prophylactic antiemetic therapy included ondansetron, metoclopramide, and/or dexamethasone. As needed, opioids (fentanyl, remifentanil, and/or hydromorphone) were given for pain control. If indicated for the surgical procedure, muscle relaxants and/or reversal agents were used. POSTOPERATIVE PHASE. Upon initial complaint of PONV, either in PACU or Day Surgery, all subjects were instructed to inhale deeply through their nose to the count of 3, hold their breath to the count of 3, and exhale to the count of 3. A single treatment was composed of 3 repetitions of this deep breathing. PONV symptoms were reassessed 5 minutes after initial complaint, and if symptoms persisted a second treatment was administered. At 10 minutes following initial complaint, symptoms were reassessed. If not resolved, subjects with persistent PONV were offered rescue with antiemetic medications. A 13-dram vial containing a cotton braid impregnated with 500 microliters of pharmacy-grade peppermint spirits (Humco, Peppermint Spirits USP: ethyl alcohol 82%, NF Grade peppermint leaf extract, peppermint oil, purified water) was placed under the nostrils at midseptum of subjects randomized to the AR group during the controlled breathing treatments. A sham vial without peppermint was used with CB subjects while they were receiving treatments. The study evaluated a single episode of PONV whether it occurred in PACU or Day Surgery. Data Collected DOS scores were obtained on admission and postoperatively, along with PONV symptoms, intraoperative antiemetic and anesthesia medications, preoperative nil per os (NPO) time, and postoperative antiemetics and opioids administered. Additionally, demographic and risk factor data included age, gender, smoking status, history of migraines, history of motion sickness, prior history of PONV, and whether preoperative aprepitant (Emend) was prescribed. Arbitrary definitions, determined a priori, were utilized to evaluate intervention effectiveness and efficacy. Treatment
effectiveness was equated with a DOS score of 0 postintervention. Efficacy was a measure of no postintervention antiemetic rescue desired by subjects regardless of their DOS score. Statistical Analyses Data were organized via descriptive statistics (mean, standard deviation [SD], frequency). Chisquared test of a contingency table was used to compare categorical data. Age was evaluated by two-tailed Student t test assuming unequal variance. To determine which risk factors contributed to PONV incidence, multiple regression was used. Significance was established at P #.05 for all inferential tests.
Results Enrollment in the study totaled 330 subjects, with 161 randomized to the control group and 169 to the experimental group prior to exclusions. Reasons for excluding subjects included unplanned hospital admission, postoperative instability, study CRNA unavailability, protocol deviations, ASA score, and subject choice. Of the 134 excluded subjects, lack of study CRNAs available (n 5 78) and deviations from study protocol (n 5 28) accounted for the majority of the exclusions. Seven subjects were excluded because of the ASA score, whereas 14 were admitted and 7 subjects withdrew themselves, resulting in 196 eligible subjects. Eligible Subject Demographics Among subjects eligible to receive intervention for PONV symptoms (N 5 196), the numbers of control (59/103) and experimental (58/93) female subjects were nearly equal. However, there were fewer control (44/103) than experimental (35/ 93) male subjects. Nonetheless, the gender distribution between the groups was not significantly different (c2 5 .53; P 5 .47). Mean ages of control (47.4 6 15.7 years [mean 6 standard deviation]) and experimental subjects (47.9 6 15.6 years) were similar (t 5 .20; P 5 .84). PONV Incidence Only 21.4% (42/196) of eligible subjects experienced nausea and/or vomiting postoperatively.
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Table 1. Demographic Characteristics of Subjects Experiencing PONV: Controlled Breathing Alone (Control) Versus Aromatherapy With Controlled Breathing (Experimental) Characteristic Gender (n) Female Male Age (y) Mean SD Range Risk factors (n) Female gender Nonsmoker Migraine history Motion sickness history PONV history
Symptomatic Control Subjects (n 5 16)
Symptomatic Experimental Subjects (n 5 26)
c 5 .788
t 5 .398
F 5 1.047
45.7 17.1 22–82
47.8 15.3 20–90
15 13 6 9 3
22 19 12 8 7
PONV, postoperative nausea and vomiting; SD, standard deviation. *Two-tailed significance at 95% confidence.
Among control subjects, the observed PONV incidence rate of 15.5% (16/103) was almost half that observed for subjects randomized to the aromatherapy with controlled breathing group (28%; 26/93). Eligible subjects were evaluated for known predictors of PONV: female gender, nonsmoking status, history of motion sickness, history of migraine headaches, and prior history of PONV. Only female gender (P 5 .0024) was found to be a significant predictor of PONV incidence. Anecdotally, the length of time patients remain NPO has been perceived by many perianesthesia nurses to be a contributing factor to the occurrence of PONV. However, no pattern emerged between PONV incidence and length of time subjects had been NPO preoperatively.
Risk Factors and PONV Symptoms
Symptomatic Subject Demographics
Intervention Efficacy and Effectiveness
Table 1 depicts characteristics of subjects who experienced nausea and/or vomiting postoperatively (n 5 42). Symptomatic subjects were overwhelmingly female (88.1%; 37/42) with only 5 males experiencing PONV, but there was no significant difference in gender distribution between the CB and AR groups (c2 5 .79; P 5 .38). Likewise, the mean ages of control and experimental subjects experiencing PONV was similar (t 5 .40; P 5 .69), with the average age of CB subjects of 45.7 years old and AR subjects averaging 47.8 years of age.
For symptomatic subjects receiving either controlled breathing or aromatherapy with controlled breathing, intervention efficacy was defined as no antiemetic rescue required. Twenty-five of 42 subjects did not desire rescue medication for their PONV symptoms. The efficacies of the CB and AR interventions were 62.5% (10/16) and 57.7% (15/26), respectively (Figure 1), a nonsignificant difference (c2 5 .09; P 5 .76).
PONV risk factors of symptomatic subjects are shown in Table 1. There was no significant difference between female gender, non-smoking status, history of motion sickness, history of migraine headaches and prior history of postoperative nausea and/or vomiting between the CB and AR groups (F 5 1.05; P 5 .41). It is noteworthy that as the number of a subject’s risk factors increased, there was a concomitant increase in the incidence of postoperative nausea and/or vomiting. PONV occurrence for subjects with two, three, and four risk factors was 14%, 32%, and 54%, respectively. PONV symptoms were observed in 83% of subjects having five risk factors.
A score of 0 on the PONV DOS was determined to demonstrate full effectiveness at the intervention
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excluded patients who reported a significant history of PONV and/or resistance to antiemetic treatment. In the Pellegrini et al study,5 subject enrollment was limited to laparoscopic general anesthesia patients having at least two of four PONV risk factors (female gender, nonsmoker, history of PONV or motion sickness), and PONV incidence was reported to be 68%. Among subjects with three or more PONV risk factors having surgical procedures less than 60 minutes, Radford et al17 found that 39.5% experienced postoperative nausea or vomiting.
Figure 1. Efficacy and effectiveness of controlled breathing versus controlled breathing with aromatherapy. Evaluations of the control and experimental interventions in symptomatic subjects were determined by a priori definitions. No need for pharmaceutical rescue was defined as intervention efficacy, whereas a self-reported DOS score of 0 was equated with intervention effectiveness. DOS, descriptive ordinal scale.
endpoint of 10 minutes. With endpoint DOS scores available for 37 of the symptomatic subjects, 13 rated their endpoint symptoms at a DOS 5 0. Among the remaining 24 subjects, end point DOS scores ranged from 2 to 10. Figure 1 illustrates that controlled breathing effectiveness (40%) exceeded that of the experimental intervention (31.8%). However, the difference in intervention effectiveness was not mathematically significant (c2 5 .26; P 5 .61). Interestingly, some subjects reporting endpoint DOS scores of 2, 3, and 4 in both groups did not desire antiemetics and one CB subject with a DOS of 5 refused rescue medication. Further, others scoring their symptoms from 2 to 5 on the DOS accepted antiemetic rescue, which confirms the variability among subjects for tolerating persistent nausea.
Discussion PONV incidence among eligible subjects in this study was less than what has been published previously. The rate of PONV observed by Winston et al13 was 41% in a study including only subjects undergoing laparoscopic and gynecological procedures scheduled for general anesthesia. They
Our study included subjects regardless of risk factor status, undergoing a wide variety of outpatient surgical procedures. This broader sample likely influenced the lower rate of PONV incidence observed (21.4%). Female gender was the only significant risk factor found to be associated with PONV incidence. Among symptomatic subjects, both the control and experimental groups were homogeneous with respect to gender, age, and presence of risk factors. Aromatherapy is one of three rescue intervention categories contained in the ASPAN guideline for postoperative management of PONV.1 The greater than 57% efficacy of inhaled peppermint aromatherapy observed in this randomized controlled trial provides supporting evidence for the inclusion of aromatherapy in managing PONV. Anderson and Gross12 suggested in their study evaluating peppermint oil, isopropyl alcohol, and saline that controlled breathing may have contributed to the relief of PONV seen in their placebo subjects; however, these researchers did not have a group exposed only to controlled breathing. The findings of our study substantiate Anderson and Gross’s suggestion, because CB subjects experienced relief from PONV to a slightly greater degree than those subjects who received aromatherapy with CB. Lack of a significant difference between efficacies of the two interventions reveals the importance of the appropriateness of the control group. The only difference between the CB and AR interventions in this study was presence or absence of peppermint in the vial placed under the subject’s nose. Furthermore, controlling the aromatherapy dosage by impregnating cotton braids with a metered
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volume of peppermint spirits in contrast to studies that have not precisely calculated the amount of aromatherapy administered to subjects. Additional review of the literature revealed a single study10— published after this study was designed and conducted—that controlled exposure using a specific volume of peppermint spirits. The standardized aromatherapy dosage and intervention protocol herein allowed for minimizing confounding variables that may have influenced previous research findings. A limitation of aromatherapy could be its duration of action as suggested by Radford et al.17 However, an intervention that approaches 60% efficacy lends credibility to its usefulness even if its effects are short-lived. Subjects in this study received CB or AR only for their initial episode of PONV. If a subsequent episode occurred during their hospital stay, subjects did not have an option of repeating the intervention. Subject attrition was the major limitation of this study, affecting many enrollees. The multidisciplinary research team approach used was deemed important, because the entire perioperative course can affect the incidence of PONV. Study design incorporated uniform protocols for general anesthesia and administration of antiemetic medications intraoperatively as well as the study intervention protocols (CB and AR) postoperatively. Close examination of data instruments revealed deviations from these protocols, which resulted in subject exclusion to preserve internal data validity. Likewise, Cotton et al14 reported similar challenges with breaches in protocol. CRNA unavailability resulted in the largest single reason for subject exclusion. Early on, recruitment of study CRNAs to the multidisciplinary team proved insufficient, which was addressed by additional recruitment and training. Thereafter, subject attrition continued because of unexpected shifting of surgical cases between operating suites, CRNA lunch/break relief, and major OR renovations that overlapped much of the study interval. Expanding procedures for eligibility from laparoscopic and ENT initially to include orthopedic and urologic procedures was requested and approved by the IRB as a countermeasure to subject attrition. Despite subject attrition, the eligible sample in
this study was about twofold larger than the largest sample found in comparable studies reviewed from 1997 to 2011.5,11-15,17 However, the symptomatic population was small, which influences the generalizability of the study findings. Aprepitant (Emend) has become more commonly used preoperatively at this facility by surgeons and anesthesiologists for patients undergoing laparoscopic procedures and/or those with a history of PONV. Aprepitant use among the sample population in this study was not found to have a significant impact on PONV incidence. It has been recommended that aprepitant is given in conjunction with other antiemetics to treat breakthrough emesis. Therefore, future studies integrating the use of aprepitant and aromatherapy should be considered. This study was designed to evaluate a single episode of PONV; however, future study designs to include recurrent episodes and unrestricted use of aromatherapy are appropriate. Finally, larger sample sizes, multisite studies, and studies including inpatient populations will improve the external validity of aromatherapy research.
Conclusions Encouraging patients to breathe deeply, in a controlled fashion, as a first line of defense in the treatment of PONV is supported by this research. When compared with traditional treatment modalities, controlled breathing can be initiated by the perioperative nurse at the bedside without delay and is not associated with any cost. Aromatherapy also proved its merit in the treatment of initial episodes of PONV. Subjects’ comments revealed satisfaction with the peppermint aromatherapy and indicated it would be beneficial to have it available throughout their recovery, in the event of recurrent episodes. These comments included, ‘‘It would be great to have this to take home and use again if I need it’’ and ‘‘The peppermint helped me.’’ A comment by a nurse subject indicated it was great and she wanted to have this available for her patients. For these reasons, consideration of unrestricted availability and use of peppermint aromatherapy may be appropriate as an alternative antiemetic therapy.
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In summary, this study sought to determine whether an inexpensive, readily available alternative to pharmaceutical medications, with no known side effects, could successfully relieve PONV in patients experiencing these symptoms. Our findings support the use of controlled breathing as a firstline countermeasure for PONV symptoms. AR proved its merit, but future research is warranted to lend credence to its unrestricted use.
Acknowledgments The authors thank Day Surgery, PACU, and CRNA staff; Sherry Hardee, MSN, RN, NEA-BC, Administrator; and Angela Brown, Administrative Coordinator, Surgical Suite; Janice H. Moore, MLS, and Karen L. Martinez, MLS, medical librarians, Northwest Area Health Education Center; Shannon Hefner, MSN, RN, CNOR, and Richmond Dental, Charlotte NC, for their support in facilitating the project.
References 1. American Society of PeriAnesthesia Nurses. Standards of Perianesthesia Nursing Practice 2008-2010. Cherry Hill, NJ: ASPAN; 2008:36-55. 2. Apfel CC, Korttila K, Abdalla M, et al. A factorial trial of six interventions for the prevention of postoperative nausea and vomiting. N Engl J Med. 2004;350:2441-2451. 3. Golembiewski J, Chernin E, Chopra T. Prevention and treatment of postoperative nausea and vomiting. Am J Health Syst Pharm. 2005;62:1247-1260. 4. Geiger JL. The essential oil of ginger, Zingiber officinale, and anesthesia. Int J Aromather. 2005;15:7-14. 5. Pellegrini JE, DeLoge J, Bennett J, Kelly J. Comparison of inhalation of isopropyl alcohol versus promethazine in the treatment of postoperative nausea and vomiting (PONV) in patients identified as at high risk for developing PONV. AANA J. 2009;77:293-299. 6. Lua PL, Zakaria NS. A brief review of current scientific evidence involving aromatherapy use for nausea and vomiting. J Altern Complement Med. 2012;18:534-540. 7. Buckle J. Aromatherapy in perianesthesia nursing. J Perianesth Nurs. 1999;14:336-344. 8. Maddocks-Jennings W, Wilkinson JM. Aromatherapy practice in nursing: literature review. J Adv Nurs. 2004;48: 93-103. 9. Potter P, Eisenberg S, Cain KC, Berry DL. Orange interventions for symptoms associated with dimethyl sulfoxide during stem cell reinfusions. Cancer Nurs. 2011;34: 361-368.
10. Lane B, Cannella K, Bowen C, et al. Examination of the effectiveness of peppermint aromatherapy on nausea in women post C-section. J Holist Nurs. 2012;30:90-104. 11. Tate S. Peppermint oil: a treatment for postoperative nausea. J Adv Nurs. 1997;26:543-549. 12. Anderson LA, Gross JB. Aromatherapy with peppermint, isopropyl alcohol, or placebo is equally effective in relieving postoperative nausea. J Perianesth Nurs. 2004;19:29-35. 13. Winston AW, Rinehart RS, Riley GP, Vacchiano CA, Pellegrini JE. Comparison of inhaled isopropyl alcohol and intravenous ondansetron for treatment of postoperative nausea. AANA J. 2003;71:127-132. 14. Cotton JW, Rowell LR, Hood RR, Pellegrini JE. A comparative analysis of isopropyl alcohol and ondansetron in the treatment of postoperative nausea and vomiting from the hospital setting to the home. AANA J. 2007;75:21-26. 15. Teran L, Hawkins JK. The effectiveness of inhalation isopropyl alcohol versus granisetron for the prevention of postoperative nausea and vomiting. AANA J. 2007;75:417-422. 16. Hines S, Steels E, Chang A, Gibbons K. Aromatherapy for treatment of postoperative nausea and vomiting. Cochrane Database of Systematic Reviews. 2012;4:CD007598. http://dx.doi.org/10.1002/14651858.CD007598.pub2. 17. Radford KD, Fuller TN, Bushey B, Daniel C, Pellegrini JE. Prophylactic isopropyl alcohol inhalation and intravenous ondansetron versus ondansetron alone in the prevention of postoperative nausea and vomiting in high-risk patients. AANA J. 2011;79:S69-74.