Acta Anaesthesiologica Taiwanica 52 (2014) 110e113

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Original Article

A comparative study of three methods of ProSeal laryngeal mask airway insertion in children with simulated difficult laryngoscopy using a rigid neck collar Bikramjit Das 1 *, Subhro Mitra 1, Arijit Samanta 2, Rajiv Kumar Samal 3 1 2 3

Department of Anaesthesiology, Government Medical College, Haldwani, India Department of Anaesthesiology, Jawaharlal Nehru Medical College, Aligarh Muslim University, Aligarh, India Department of Anaesthesiology, Institute of Post Graduate Medical Education and Research, Kolkata, India

a r t i c l e i n f o

a b s t r a c t

Article history: Received 20 February 2014 Received in revised form 19 May 2014 Accepted 22 May 2014

Background: Combined introducer tool and stylet technique of ProSeal laryngeal mask airway (PLMA) insertion was compared with the conventional digital manipulation and introducer tool technique in children with a rigid neck collar. Methods: This was a randomized, single blinded, prospective study. Ninety ASA Grade IeII children weighing 10e20 kg were randomly allocated for PLMA insertion using the digital, introducer tool (IT) or combined IT and stylet techniques. Each group contained 30 patients. Difficult laryngoscopy was simulated using a rigid neck collar. The laryngoscopic view was graded prior to PLMA insertion. The digital and IT techniques were performed according to the manufacturer's instructions. The combined technique involved attaching the IT to the PLMA and inserting a flexible stylet through the drain tube. Results: The median Cormack and Lehane grade was 2 in all three groups. Insertion was more frequently successful with the combined technique at the first attempt (combined 100%, digital 65.38%, IT 66.67%; p < 0.05), but success after three attempts was similar (combined 100%, digital 86.67%, IT 90%; p > 0.05). The time taken for successful placement was similar among groups at the first attempt, but was shorter for the combined technique for overall attempts (combined 18.33 ± 1.27 seconds, digital 27.85 ± 9.05 seconds, IT 26.89 ± 7.17 seconds; p < 0.05). There was no difference in postoperative airway morbidity. Conclusion: PLMA insertion with combined IT and stylet technique was more frequently successful than the digital or IT technique in pediatric patients without cervical spine motion. Copyright © 2014, Taiwan Society of Anesthesiologists. Published by Elsevier Taiwan LLC. All rights reserved.

Key words: laryngoscopy: difficult; laryngeal masks: ProSeal

1. Introduction Insertion of ProSeal laryngeal mask airway (PLMA) requires the “sniffing” position.1 The manufacturer recommends insertion of PLMA using digital manipulation (classic LMA) or with an introducer (intubating LMA), and these techniques demand flexion at the lower cervical spine and extension of the atlanto-occipital joint. This neck motion is often not possible in children with suspected cervical instability or cervical spine is externally fixed due to any reason. Several techniques have been introduced to improve the

Conflicts of interest: All authors declare no conflicts of interest. * Corresponding author. Flat 6, Type-III, Block-D, Government Medical College campus, Haldwani (Nainital) 263139, Uttarakhand, India. E-mail address: [email protected] (B. Das).

insertion success rate: the use of flexible fiberscope2; gum-elastic bougie (GEB)3,4; gastric tube5; and a suction catheter.6 However, none of these techniques would be easy to perform without neck movement, particularly in emergency situations. There are no studies comparing the different methods of PLMA placement without the “sniffing” position in children. In this study, we compared a relatively new technique of PLMA insertion in children with the conventional techniques such as digital manipulation and introducer tool (IT) technique without the “sniffing” position. The new technique is a combined introducer tool and stylet technique. We compared these three techniques in terms of success rates at the first attempt and insertion time for an effective airway. Hemodynamic effects and any immediate or early complication because of insertion of the device were also noted.

http://dx.doi.org/10.1016/j.aat.2014.05.009 1875-4597/Copyright © 2014, Taiwan Society of Anesthesiologists. Published by Elsevier Taiwan LLC. All rights reserved.

Three methods of ProSeal LMA insertion

111

2. Materials and methods Ninety patients (American Society of Anesthesiologists physical status I or II, weight 10e20 kg) undergoing lower abdominal, inguinal, and orthopedic procedure of 45 mmHg was noted. A well-lubricated 10F gastric tube was inserted through the drain tube. Correct gastric tube placement was assessed by suction of fluid or detection of injected air by epigastric stethoscopy. Three attempts were allowed before insertion was considered a failure. Failed insertion was defined by any of the following criteria: (1) failed passage into the pharynx; (2) malposition (air leaks or failed gastric tube insertion if pharyngeal placement successful); and (3) ineffective ventilation (end-tidal CO2 > 45 mmHg if correctly positioned). The time between picking up the prepared PLMA (cuff deflated, lubricated, IT and stylet attached) and successful placement was recorded. The reason for failed insertion was documented. If insertion failed after three attempts, the Select Collar was removed and patient was intubated. Once insertion was successful, the intracuff pressure was set at 60 cmH2O using a digital manometer (Mallinckrodt Medical, Hennef, Germany). Hemodynamic data were collected before and immediately after PLMA insertion. Visible blood staining on the PLMA was noted at removal. Data on failed passage into the pharynx, insertion time, and the etiology of failure were collected by an unblinded observer. Data on malpositions, effective ventilation, hypoxic episodes, and blood staining were collected by an observer blinded to the insertion technique. Statistical analysis was done using SPSS software version 17.0 (SPSS Inc., Chicago, IL, USA). Sample size was based on a projected difference of 30% among the groups for first attempt success rate, a type I error of 0.05, and a power of 0.8, and was based on studies reporting first attempt success rates.14e17 The demographic data (age, height, weight), time of insertion, and hemodynamic parameters were analyzed by analysis of variance. Insertion success was analyzed by Fisher's exact test. Complications were analyzed with Chi-square test. Data are mean (standard deviation) unless otherwise stated. Significance was taken as p < 0.05.

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3. Results

Table 2 Comparison of the three groups.

There were no differences in demographic data and Cormack and Lehane score among the three groups (Table 1). Insertion was more frequently successful with the combined technique at the first attempt than the digital or IT techniques (p < 0.05), but overall success was statistically similar (Table 2). The time taken for successful placement was similar among groups at the first attempt, but was shorter for the combined technique after three attempts (p < 0.05). The digital technique failed in four patients and the IT technique failed in three. There were no failed uses of the combined technique. The etiology and frequency of failed insertions were similar for the digital and IT techniques (Table 2). There was neither desaturation nor any significant change in mean arterial pressure or heart rate before and after insertion of PLMA in any case (Table 3). There was no laryngospasm in any patient. There were no differences in the frequency of visible blood among groups (Table 3). 4. Discussion The conventional techniques (digital manipulation and IT) of ProSeal LMA insertion requires the “sniffing” position of the patient, i.e., flexion at the lower cervical spine and extension of the atlanto-occipital joint.1 However, these techniques have not been proven equally efficient in situations without cervical spine motion compared to the “sniffing” position. However, this position is not possible in children where cervical spine movement is either contraindicated (e.g., head neck trauma) or not possible (cervical collar). Children with rigid neck collar may make placement of the PLMA more difficult, because the angle between the oral and pharyngeal axes becomes acute at the back of the tongue.18 In our study, the application of a rigid neck collar simulates difficult laryngoscopy by reducing both head and neck movement (necessary to align the oropharyngeal axes) and mouth opening (necessary to insert laryngoscope blade). The median Cormack and Lehane score was 2 in all three groups. The combined technique was more successful because it reduces impaction at the back of the mouth, prevents folding over of the distal cuff, and guides the distal cuff directly into its correct position in the hypopharynx.19 The distal curvature extending up to the mask tip made the negotiation of the oropharyngeal curvature easier in an otherwise fixed head and neck position. Furthermore, keeping the distal end of the stylet till the tip of the drain tube prevented the folding back of the PLMA as it met the posterior pharyngeal wall. Withdrawing the stylet by approximately 4e5 cm after negotiating the oropharyngeal curve restored the original shape of the device without disturbing progress of the tip of the PLMA towards the upper esophageal opening as confirmed by subsequent smooth passage of the gastric tube.11 The less successful first attempt insertion as well as high numbers of failure in digital group was mainly due to two reasons. First, children with the Select Collar had restricted mouth opening, Table 1 Patient characteristics.

Age (mo) Weight (kg) Height (cm) Sex Male:female CormackeLehane view:1/2/3/4

Digital (n ¼ 30)

IT (n ¼ 30)

Combined (n ¼ 30)

p

38.83 (9.06) 14.93 (2.65) 99.27 (4.28)

34.97 (8.5) 15.90 (2.55) 98.3 (4.25)

34.03 (7.63) 15.70 (2.3) 100.03 (3.23)

0.07 0.29 0.24

19:11 0/24/5/1

22:8 1/25/2/2

23:7 1/23/5/1

0.59 0.49

Data are presented as mean (standard deviation) for age, weight, and height.

Insertion success First Second Third Overall Insertion time (s) First Overalla Etiology of failure Failed passage into pharynx Malpositionsb Failed ventilationc

Digital (n ¼ 30)

IT (n ¼ 30)

Combined (n ¼ 30)

17 5 4 26

18 7 2 27

30 0 0 30

20.06 (0.90) 27.85 (9.05)

20.44 (1.04) 26.89 (7.17)

18.33 (1.27) 18.33 (1.27)

0.32 0.0024*

3

1

0

0.14

1 0

2 0

0 0

p

0.0021* 0.15

Data are presented as mean (standard deviation). * Statistically significant. a Data from the seven failed insertions not included. b Drain tube air leaks and failed gastric tube insertion if pharyngeal placement successful. c End tidal CO2 > 45 mmHg if correctly positioned.

which resulted in difficult PLMA insertion because there was less space to accommodate the shaft of the PLMA and finger of the operator. Second, in the digital manipulation method, the index finger rests in the junction between the shaft and the mask, leaving the larger and softer mask without any support. This causes the tip of the PLMA to fold over while negotiating it through the oropharynx in neutral position.20 The failure rate in the IT group was greater than in the combined group but less than in the digital group. Presence of the IT instead of the finger in the restricted mouth opening situation made PLMA insertion relatively easier as it consumed less space, but the failure rate was still higher than the combined group because the IT was inserted into the locating strap at the junction of the shaft and the mask. For this reason, the possibility of the PLMA tip to fold over remained the same, like the finger insertion technique, as there was no rigid structure to provide support to the larger mask of the PLMA.20 The combined technique avoids both these problems. By this technique, PLMA can be inserted through the restricted mouth opening as well as there is no chance of folding over of the tip because the rigid stylet which is extended to the tip, provides adequate support to the mask with the patient in a neutral position.11 According to Chen et al,20 insertion of the PLMA with a Flexi-Slip stylet has a higher success rate at first attempt and requires less time than the IT, but in that study, PLMA was inserted in the “sniffing” position in adult patients. Eschertzhuber et al19 conducted a study comparing GEB-guided PLMA insertion with digital Table 3 Hemodynamic parameters and complications.

Heart rate/min Before insertion After insertion MAP (mm Hg) Before insertion After insertion Complications Bucking, coughing, laryngospasm (on insertion) Blood staining (on removal)

Digital (n ¼ 30)

IT (n ¼ 30)

Combined (n ¼ 30)

p

86.80 (4.94) 89.47 (4.93)

87.13 (4.29) 89.87 (3.82)

89.13 (4.86) 91.53 (4.71)

0.12 0.18

74.11 (2.91) 77.24 (3.10)

73.95 (3.49) 76.57 (3.45)

75.69 (2.72) 78.42 (2.65)

0.96 0.94

0

0

0

2

4

3

Data are presented as mean (standard deviation).

0.99

Three methods of ProSeal LMA insertion

and IT technique in neutral position in adult patients. They concluded that GEB-guided PLMA insertion was superior to those two conventional methods in restricted cervical spine motion and was the best back-up method in case of failure of either of those techniques. However, there are potential disadvantages with GEBguided PLMA insertion technique.19 In this technique, laryngoscopy is mandatory for placement of the GEB in the esophagus, but laryngoscopy is difficult in this situation as there is nonalignment of oroepharyngealelaryngeal axes and restricted mouth opening. Besides that, the risk of esophageal trauma remains with the GEB guided technique21 as the tip of the GEB is not atraumatic, particularly in the delicate esophageal mucosa of pediatric patients. Furthermore, this technique cannot be executed by unskilled personnel because it requires laryngoscopy to place the GEB inside the esophagus. Drolet and Girard5 and Gracia-Aguado et al6 described a similar guided technique for the PLMA using a gastric tube and a suction catheter, respectively. An advantage of the gastric tube and the suction catheter is that these are less traumatic than the GEB; however, these may not be sufficiently stiff to guide the PLMA around the back of the mouth.4 Furthermore, successful use of these techniques has not been proven in pediatric patients with immobilization of the head and neck. There was no significant difference in heart rate and mean arterial pressure in the three groups before and after PLMA insertion. The incidence of complications (airway trauma) was very low in all cases except for blood staining in a few children in the IT and combined groups, which was neither clinically important nor statistically significant. 5. Conclusion We conclude that combined IT and stylet technique is the best method for ProSeal LMA insertion in pediatric patients without cervical spine motion. Moreover, this technique may have a potential role during cardiopulmonary resuscitation of the pediatric patient whose neck is stabilized. References 1. LMA Pro-Seal® Instruction Manual. Available from: http://www.intaventdirect. co.uk/files/lma_pro-seal_book_issue_3_aug_2009.pdf [accessed 22.01.12]. 2. Brimacombe J, Keller C. Awake fiberoptic guided insertion of ProSeal laryngeal mask airway. Anesthesia 2002;57:719.

113 3. Howarth A, Brimacombe J, Keller C. Gum elastic bougie-guided insertion of the Proseal laryngeal mask airway: A new technique. Anaesth Intens Care 2002;30: 624e7. 4. Brimacombe J, Keller C, Judd DV. Gum elastic bougie-guided insertion of the ProSeal laryngeal mask airway is superior to the digital and introducer tool techniques. Anaesthesiology 2004;100:25e9. 5. Drolet P, Girard M. An aid to correct positioning of the ProSeal laryngeal mask. Can J Anaesth 2001;48:718e9. 6. Gracia-Aguado R, Vinoles J, Brimacombe J, Vivo M, Lopez-Estudillo R, Ayala G. Suction catheter guided insertion of the ProSeal laryngeal mask airway is superior to the digital technique. Can J Anaesth 2006;53:398e403. 7. MacQuarrie K, Hung OR, Law JA. Tracheal intubation using Bullard laryngoscope for patients with a simulated difficult airway. Can J Anaesth 1999;46: 760e5. 8. Komatsu R, Nagata O, Kamata K, Yamagata K, Sessler D, Ozaki M. Intubating laryngeal mask airway allows tracheal intubation when the cervical spine is immobilized by a rigid collar. Br J Anaesth 2004;93:655e9. 9. Wakeling HG, Nightingale J. The intubating laryngeal mask airway does not facilitate tracheal intubation in the presence of a neck collar in simulated trauma. Br J Anaesth 2000;84:254e6. 10. Drage MP, Nunez J, Vaughan RS, Asai T. Jaw thrusting as a clinical test to assess the adequate depth of anaesthesia for insertion of the laryngeal mask. Anaesthesia 1996;51:1167e70. 11. Khan RM, Sharma PK, Kaul N, Sumant A. Combined use of stylet and introducer tool in ProSeal™ laryngeal mask aids insertion in halo frame immobilized patient. Internet J Anesthesiol 2008;18. 12. Keller C, Brimacombe J, Keller K, Morris R. A comparison of four methods for assessing airway sealing pressure with the laryngeal mask airway in adult patients. Br J Anaesth 1999;82:286e7. 13. Brimacombe J, Keller C, Kurian S, Myles J. Reliability of epigastric auscultation to detect gastric insufflation. Br J Anaesth 2002;88:127e9. 14. Keller C, Brimacombe J. Mucosal pressure and oropharyngeal leak pressure with the ProSeal versus the classic laryngeal mask airway in anaesthetized paralysed patients. Br J Anaesth 2000;85:262e6. 15. Brimacombe J, Keller C. Stability of the LMA-ProSeal and standard laryngeal mask airway in different head and neck positions. A randomized crossover study. Eur J Anaesthesiol 2003;20:65e9. 16. Brimacombe J, Keller C. The ProSeal laryngeal mask airway. A randomized, crossover study with the standard laryngeal mask airway in paralyzed, anesthetized patients. Anesthesiology 2000;93:104e9. 17. Evans NR, Gardner SV, James MF, King JA, Roux P, Bennett P, et al. The ProSeal laryngeal mask: results of a descriptive trial with experience of 300 cases. Br J Anaesth 2002;88:534e9. 18. Asai T, Murao K, Shingu K. Efficacy of the ProSeal laryngeal mask airway during manual in-line stabilisation of the neck. Anaesthesia 2002;57:918e20. 19. Eschertzhuber S, Brimacombe J, Hohlrieder M, Stadlbauer KH, Keller C. Gum elastic bougie-guided insertion of the ProSeal laryngeal mask airway is superior to the digital and introducer tool techniques in patients with simulated difficult laryngoscopy using a rigid neck collar. Anesth Analg 2008;107:1253e6. 20. Chen HS, Yang SC, Chien CF, Spielberger J, Hung KC, Chung KC. Insertion of the ProSeal™ laryngeal mask airway is more successful with the Flexi-Slip™ stylet than with the introducer. Can J Anaesth 2011;58:617e23. 21. Kadry M, Popat M. Pharyngeal wall perforationdan unusual complication of blind intubation with a gum elastic bougie. Anaesthesia 1999;54:404e5.

A comparative study of three methods of ProSeal laryngeal mask airway insertion in children with simulated difficult laryngoscopy using a rigid neck collar.

Combined introducer tool and stylet technique of ProSeal laryngeal mask airway (PLMA) insertion was compared with the conventional digital manipulatio...
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