1、Using the Laryngeal Mask Airway,Norman L. Goody, MD,Objective,Using the LMA LMA and the Difficult Airway LMA and Pediatric Anesthesia LMA and OB Anesthesia Advantages of Using the LMA,Disadvantages of the LMA Complications Arising from Use of the LMA Contraindications to Using the LMA,History of the
2、 LMA,development began in 1981 at Royal London Hospital by Dr. Archie Brain modification of the Goldman Dental Maskavailable commercially in UK since 1988 and in the US since 1992 now used in 50% of general anesthetics in some centers in UK (and probably US, too- especially ambulatory surgery),Chara
3、cteristics of the LMA,Latex free, medical-grade silicone Aperture bars Sizes #1 6.5 kg 2-5 ml #2 6.5-25 kg 7-10 ml #2 1/2 20-30 kg 14 ml #3 25-70 kg 15-20ml #4 70+ kg 25-30ml,Using the LMA,Preparation of the LMA Check patency of cuff Lubricate POSTERIOR surface only Surgilube v. lidocaine jelly Indu
4、ction Insertion of the LMA Common Problems Cricoid Pressure Securing the LMA,Using the LMA,Maintenance of Anesthesia Removal of the LMA Cleaning, Sterilization and Re-use,Determining Life Span of LMA,intended for 40-50 uses, but highly over-manufactured tube remains translucent aperture bars remain
5、intact cuff deflates correctly no valve leakage cuff remains symmetric pilot balloon retains shape connector remains tight/ not broken,THE LMA IS NOT DISPOSABLE,LMA and the Difficult Airway,Awake Intubation Difficult MASK Airway Blind Intubation Failed Intubation Fiberoptic Bronchoscopy and the LMA
6、Emergent Intubation by an Unskilled Provider,LMA and Pediatric Anesthesia,DL&B tracheal stenosis difficult airway,Accuracy of End-tidal CO2 in Pediatrics using LMA,22 children, mechanically ventilated to a stable ETCO2 ventilation via the LMA mean ETCO2 and PaCO2 obtained were 37.7 +/- 3.3 and 41.9
7、+/- 9.09, respectively ventilation via ETT mean ETCO2 and PaCO2 obtained were 35.2 +/- 2.9 and 39.2 +/- 5.25, respectively LMA ETCO2 is as accurate an indicator of PaCO2 as when ventilated via ETTAnesth Analg Feb;82 (2) :247-50,LMA and OB Anesthesia,Questionnaire to 250 anesthesiologists in the UKLM
8、A was available in 91.4% of obstetric units 72% were in favor of using LMA for failed intubation with inadequate ventilation via face mask 24 had experience with LMA in such a situation, 8 of which stated that LMA had proved to be a “lifesaver” Authors believed that we should use LMA before cricothy
9、roidotomy for failed intubation/ventilationCan J Anaesth Gataure, et al. 1995 Feb;42(2):130-3,Advantages of Using the LMA,Meta-analysis comparing advantages of the LMA over the tracheal tube or face mask Reviewed 858 LMA publications identified to December 1994, of which 52 met criteria for analysis
10、 32 different issues were testedCan J Anaesth Brimacombe 1995 Nov;42(11):1017-23,Advantages of LMA over ETT,increased speed and ease of placement by inexperienced personnel increased speed of placement by anesthetists improved hemodynamic stability at induction and during emergence minimal increase
11、in intraocular pressure following insertion Can J Anaesth Brimacombe 1995 Nov;42(11):1017-23,Advantages of LMA over ETT,reduced anesthetic requirements for airway tolerance lower frequency of coughing during emergence improved oxygen saturation during emergence lower incidence of sore throats in adu
12、ltsCan J Anaesth Brimacombe 1995 Nov;42(11):1017-23,Advantages of LMA over Face Mask,easier placement by inexperienced personnel improved oxygen saturation less hand fatigue improved operating conditions during minor pediatric otological surgeryCan J Anaesth Brimacombe 1995 Nov;42(11):1017-23,Additi
13、onal Advantages of Using the LMA,leaves providers hands free patient can produce effective cough allows spontaneous ventilation even malpositioned can adequately ventilate,Disadvantages of LMA over the ETT,lower seal pressure higher frequency of gastric insufflationCan J Anaesth Brimacombe 1995 Nov;
14、42(11):1017-23,Disadvantages of LMA over the FM,esophageal reflux more likelyCan J Anaesth Brimacombe 1995 Nov;42(11):1017-23,Contraindications to Using the LMA,Full Stomach Non-fasted 34+ week pregnant trauma acute abdomen thoracic injury opiate premedication autonomic neuropathy,patient unable to
15、follow instructions any condition known to delay gastric emptying,Contraindications to Using the LMA,Full Stomach Patients with a history of GE reflux,Contraindications to Using the LMA,Full Stomach Patients with a history of GE reflux Patients with low pulmonary compliance needing positive pressure
16、 ventilation,Complications Arising from Use of the LMA,Aspiration,Passive Regurgitation and the LMA,Study looked at gastric regurgitation during GA in different positions with the LMA 15 minutes before induction, patients swallowed a 75 mg methylene blue capsule. supine, Trendelenburg and lithotomy
17、positions post-op, LMA and oropharynx were inspected for bluish discoloration No blue dye was detected in the supine group but it was observed in one patient in each of the other two groups Anaesthesia Strong, et al. 1995 Dec;50(12):1053-5,Passive Regurgitation: LMA v. ETT,Study at UT Dallas compari
18、ng incidence of reflux for spontaneously breathing anesthetized patients with either an ETT or LMA by continuous measurement of hypopharyngeal pH“Continuous monitoring.failed to detect evidence of pharyngeal regurgitation.”Anesth Anal Joshi, et al. 1996 Feb;82(2):254-7,Complications Arising from Use
19、 of the LMA,Aspiration Coughing,Complications,Incidence of airway complications following GA using either ETT or LMA Significantly greater incidence of coughing PRIOR to extubation, AT extubation and AFTER extubation in the ETT group than in the LMA groupNo airway complications were seen in either g
20、roupJR Soc Med Denny, et al. 1993 Sep;86(9):521-2,Complications Arising from Use of the LMA,Aspiration Coughing Sore Throat,Sore Throat,incidence of sore throat looked at in 327 patients who had GAmild/moderate soreness 7% of patients with LMA 10% who had FM and oral airway 47% of had ETT 24 hours l
21、ater, 3% of intubated group still c/o severe soreness, while NONE of the other patients had any c/o,Other Uses for the LMA,Bronchoscopy “Big MAC” Oral Surgery Head and Neck Surgery Professional Singers Laparoscopic Surgery?,Conclusions,Many advantages over ETT and FM Useful in many areas of anesthes
22、ia care Especially useful in outpatient anesthesia Safe when used appropriately,Take Home Message,routinely test the cuff before use avoid lubricating the anterior surface of the mask only insert the LMA when an adequate depth of anesthesia has been obtained maintain an adequate anesthetic depth throughout surgery avoid disturbing the patient during emergence keep the cuff inflated until the patient is awake,