Laryngeal Mask Airway Placement Methods in Pediatric Care

Laryngeal Mask Airway Placement Methods in Pediatric Care Laryngeal Mask Airway Placement: Comparison Between a Traditional and Alternative Methods in Pediatric Practice ============================================================ Emil Batarseh , MD , JBA* Zahi Majali , MD , JBA Basel D.Makhamreh , MD , JBA Abstract Objective To compare the quality of laryngeal mask airway placement between an alternative and a traditional methods in children. Methods Our prospective ,double-blind investigation enrolled 105 children subjects , aged 3months-15 years,of both genders,ASA I(American society of anesthesiologists), and assigned for different elective minor superficial operations under general halothane inhalational spontaneous laryngeal mask airway anesthesia at Princess Haya hospital-Aqaba-Jordan,during the period July 2007-July 2008. Subjects were randomized into two groups.Group I subjects (n=50) received laryngeal mask airway (LMA) through an alternative method,and group II subjects (n=55) received laryngeal mask airway via the traditional method. The number of placement attempts and duration required for success to attain a patent airway in both groups were recorded. Results Placement method made no difference in terems of first trial success (P>0.05).First trial successful placement was 85.5% and 90% in groups II and I respectively. Conclusion The alternative placement method is an acceptable solution to the traditional method. Key words:Anesthesia:general,spontaneous;LMA:traditional,alternative;children. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ *Corresponding author: Department of anesthesia , intensive care and pain management , KHMC , AMMAN , JORDAN. E-mail: [emailprotected]yahoo.com 1 Introduction Use of laryngeasl mask airway permits the maintenance of a patent airway with successful insertion rates of the LMA on the first attempt , varying between 67-92% in pediatric practice (1).Since its introduction in 1983 by Brain,the LMA has achieved increasing popularity (2). The laryngeal mask airway has achieved a great popularity also in pediatric anesthesia practice.The laryngeal mask airway is a novel device that fills the gap in airway management between endotracheal intubatio and the use of face mask.The laryngeal mask airway is inserted blindly into the pharynx,forming a low pressure seal aroud the laryngeal inlet. Because the insertion of the laryngeal mask airway by the standard technique is not always easy in children due to the posterior pharyngeal curvature,some different maneuvers have been described to minimize this problem(3):Innserting the LMA laterally,applying the mask firmly against the hard palate,pulling the tongue forward,repositioning the head,adding or removing air to the cuff,applying continuous positive airway pressure,usig a laryngoscope and inserting the LMA like a Guedel oropharyngeal airway. The ability to maintain a patent airway and provide effective ventilation is the main objective of pediatric anesthesiological procedures.This is achieved mainly with the use of a face mask or an endotracheal tube.Both of these devices have major limitations from a strictly anatomical point of view and require adequate operator skills.The aim of LMA was of producing an airway device that would be more practical than the face mask and less invasive than the tracheal tubes.The functional ehegance of the LMA is that it forms a low pressure airtight seal against the glottis rather than plugging the pharynx,thus combining ease of insertion and adequaqte airway patency (4). Airway management is more successful with LMA technique.This is because transoral passage of instrumentation into the hypopharynx is easier than into the glottic inlet.There are four reasons:Firstly,the hypopharynx is a posterior structure and is easier to locate.Secondly,it is wider providing a bigger target.Thirdly,it is funnel-rather than tubular –shaped ,so that imprecisely positioned instrumentation will be redirected to the target and fourthly,it is better aligned with the oropharyngeal axis,making instrumentation less likely to get snagged (3). The objective of our invewstigation was to asses the effectiveness of the modified procedure in comparison to the standard procedure regarding LMA insertion. 2 Methods Our prospective,double blind investigation included 105 children patients,aged 3months-15 years,ASA I,of both sexes and scheduled for various elective minor superficial surgical procedures under general halothane inhalational spontaneous laryngeal mask airway anesthesia at Princess Haya hospital-Aqaba-Jordan,during the period July 2007-July2008,after obtaining approval from the local ethics committee of the Jordanian royal medical service directorate and written informed consent from the parents..Subjects were randomly divided into two groups using sealed envelopes.Group I children (n=50) received LMA using the modified method and group II children (n=55) received LMA via the standard method.The size of the LMA used was indicated using the patients body weight;size 1,1.5,2,2.5 ad 3 masks for 30 kgof body w2eight ,respectively. The LMA was lubricated with saline before insertion.Induction of inhalational anesthesia was performed with 3-5%halothane mixed with70% nitrous oxidein 30%oxygen.Before insertion of the LMA ,anesthesia was maintained using 2-3%halothanne in oxygen.No muscle relaxants were used.An anesthesia technician opened the patients mouth by pulling down the jaw.Intravenous cannulation was done after child is anesthetized,if The standard insertion procedure was illustrated by Brain(5).The LMA was inserted with the cuff fully deflated and against the palate,then the cuff was inflated after insertion.In the modified insertion procedure,a two-thirds moderately inflated LMA (using 2,4,6,8 and 12 ml air for size 1,1.5,2,2.5 and 3 masks respectively) was inserted with its lumen facing laterally left.While rotated clockwise 90 D,it was passed downward into position behind the larynx.Then the cuff was fully inflated.Successful insertion was clinically called for if manual ventilation with the reservoir bag was easy and the chest wall movement was smooth. The number of trials on LMA onnsertion and the duration to achieve good airway were recorded.Vital signs including heart rate and pulse oximeter readings were recorded.In case of failed LMA insertion,endotracheal intubation was achieved.An observer blinded to the insertion procedure evaluated the two procedures. Statistics Parametric data were analyzed using Students t test.P-value 3 Results There were no significant differences in terms of gender,age,weight,duration of anesthesia and size of the LMA.Table 1.Overall study group was 110 children patients,but 5 were excluded from the investigation ,who were ASA II and III physical status classified. Successful insertion was attained in 85.5% of subjects in group II and in 90% of patients in group I,at first trial.The two groups were comparable regarding the successful insertion rate,the number of trials at insertion(Second trial;GII,4 and GI,3.P>0.05.Third trial;GII,3 and GI,2,P>0.05) and the duration required for insertion (GII,0.4 minutes and GI,0.37 minutes,P>0.05). Endotracheal intubation was achieved in 1 case in GII and in no case in GI,P>0.05.In the present study,the LMA standard approach success rate was 85.5% at first trial ,increasing to 92.7% at second trial and 98.2% at third trial.In the modified approach,the success rate was 90% at first trial but was 96% at second trial and 100% at third trial. 4 Table 1. Patients characteristics. 5 Table 2. LMA insertion comparison. 6 Discussion The LMA has become popular in pediatric aesthesia practice.Nagai S,et al showed the potency of the modifiedmethod of LMA insertion (6).LMA advantages over conventional laryngoscope guided tracheal intubation are more rapid insertion and increased success rate.The modified method can be used in this investigation as an alternative procedure to the standard method of insertion.Brimacombe and Berry (7) stated that if the standard approach is used correctly,the first time success rate should be >98% in less than 20 seconds. Wakeling et al(8) demonstrated that deflating the cuff first would allow more difficult insertion due to the presentation of a softer edge to the posterior pharyngeal wall.Lopez-Gil,et al(9) used a lubricant ,whereas we moistened the LMA with saline only.He demonstrated that there was a rapid improvement in LMA skills in pediatric anesthesia practice when the standard technique was used.Gaining more experience may decrease the rate of unsuccessful insertion.Airway trauma was less frequent with the LMA than with ETI.This is not surprising as more force is required to see the glottic inlet than the hypopharynx.Perhaps the pharyngeal/esophageal mucosa is stronger than the laryngeal/tracheal mucosa as it has evolved to accommodate solid bodies and not just passaqge of gas. This modified technique I which a two –thirds inflated LMA is inserted with its lumen facing laterally forces the patients mouth to open wider and keeps the tongue from being pushed back into the air passage.These technical features result in easy insertion through the pharynx for inexperienced anesthesiologists.In addition,the softer edge of the partially inflated LMA protects the pharyngeal mucosae from trauma during insertion.Causes of difficulty with LMA onsertion include choice of wrong LMA size and difficulty in maneuvering through the posterior curvature of the pharynx (10).Differences in the airway anatomy and the frequent presence of tonsillar hypertrophy can complicate LMA insertion in children.Maneuvers to overcome this difficulty include increased head extension,jaw thrust maneuvers puuling the tongue forward,firm pressure on the LMA and using the index finger to guide the mask(10). Oneil et al (11) have reported an alternative method of insertion with the LMA partially inflated in children.They described improved ease of insertion and explained that the softness of the inflated cuff allows for easier adaptation to the differing pharyngeal characteristics of the pediatric airway. Nevertheless,Braincompared insertion techniques concerning the mechanisms of deglutition and recommended the standard technique. Although both methods of insertion were satisfactory,partial inflation of the LMA improved the ease of insertion in children as assessed by time to insertion and success rate on the first attempt.Inflation of the cuff at the smaller sized LMA after insertion often displaces the LMA and alters its position while the inflated LMA tends to insert to the proper depth and requires no further adjustment.In the standard technique,however,insertion of the LMA is not always easy.Therefore,it is reasonable that anesthesiologists devise other insertion techniques.We believe that this technique is to be recommended in certain situations. 7 Trevisanuto et al (12) found that the occurrence of first time failure decreased overtime in their study and they thought that the change represented an element of familiarization with the LMA insertion technique.The relatively small but statistically significant difference is meaningful,sice problems associated with insertion can be attributed to inadequate depth of anesthesia which may occur with prolonged placement.Our 1.8% incidence of problems that resulted in abandonment of the LMA is comparable to that reported in similar study evaluating uses of the LMA in pediatric practice(1). In Conclusion This modified techniqueia an acceptable alternativeto the standard technique I children.Thie techniqueis likelyto allow easy insertion of the LMA for unskilled anesthesiologists.Insertion of the LMA with the cuff inflated is equallysuccessfulto the standard uninflated techiquein experienced anesthesiologists.This implies that the modified inflated approach would be accepted to the general population of LMA users. 8 References 1.Shahin NJ , Mehtab A , Hammad U , et al. A study of the use of laryngeal mask airway (LMA) in children and its comparison with endotracheal intubation.Indian journal of anaesthesia 2009;53(2):174-8. 2.Pennant JH , White PF. The laryngeal mask airway.Its uses in anesthesiology. Anesthesiology 1993;79:144-63. 3.Benumof JL. Laryngeal mask airway.Indications and contraindications.Anesthesiology 1992;77(5):843-6. 4.Ghai B , Wig J . Comparison of different techniques oh laryngeal mask placement in children. Curr opin Anesthesiol 2009;22(3):400-4 5.Patel B, Bingham R.Laryngeal mask airway and other supraglottic airway devices in pediatric practice.BJA 2009;9(1):6-9 6.Nagai S , Inagaki Y , Hirosawa J , et al. Modified insertion technique of the laryngeal mask airway in children:a comparison with standard technique. Anaesthesia 2003:59-61. 7.Brimacombe J , Berry A. The laryngeal mask airway :anatomical and physiological implications. Acta Anesthesiol scand 1996;40(2):201-9. 8.Wakeling HG , Butler PJ , Baxter PJC.The laryngeal mask airway:a comparison between two insertion techniques.Anesth Analg 1997;85:687-90. 9.Lopez GM , Brimacombe J , Cebrian J , et al.Larygeal mask airway in pediatric practice. Anesthesiology 1996;84(4):807-11. 10.Ghai B , Makkar JK , Bhardwai N, et al.Larygeal mask airway insertion in children:comparison between rotational,lateral and standard techniques. Pediatric anesthesia 2008;18(4):308-12 11.Oneill B , Templeton JJ , Caramico L, et al.The laryngeal mask airway in pediatric patients:factors affecting ease of use during insertion and emergence. Anesth Analg 1994;78:659-62. 12.Trevisanuto D , Micaglio M , Ferrarese P , et al.The laryngeal mask airway:potential applications in neonates. Fn.bmj.com 2008.www.archdischild.com. 9