1046
portal hypertensive rates,"21 it was logical to see whether beta-adrenergic antagonists were effective in severe gastric mucosal haemorrhage. Two small open studies have shown that propranolol stops such bleeding in almost all cases,23.24; in a randomised controlled trial in a larger number of patients the frequency of rebleeding was significantly reduced.1 The mechanism of the beneficial effect of propranolol is uncertain. There is no evidence yet that the long-term outcome of cirrhotic patients with severe portal hypertensive gastropathy, or those with bleeding varices, is improved by either surgery or beta-adrenergic blockade. 1.
Perez-Ayuso RM, Piqué JM, Bosch J, et al. Propanolol in prevention of recurrent bleeding from severe portal hypertensive gastropathy in cirrhosis. Lancet 1991; 337: 1431-34. TT, Sims J, Eyre-Brook I,
2. McCormack
hypertension: inflammatory gastritis
al. Gastric lesions in portal congestive gastropathy? Gut
et
or
1985; 26: 1226-32. 3.
Quintero E, Piqué JM, Bombi JA, et al. Upper gastrointestinal bleeding caused by gastroduodenal vascular malformations: incidence, diagnosis, and treatment. Dig Dis Sci 1986; 31: 897-905. 4. Dagradi AE, Mehler R, Tan DT, Stempien SJ. Sources of upper gastrointestinal bleeding in patients with liver cirrhosis and large esophagogastric varices. Am J Gastroenterol 1970; 54: 458-63. 5. Khodadoost J, Glass GBJ. Erosive gastritis and acute gastroduodenal ulcerations as source of upper gastrointestinal bleeding in liver cirrhosis. Digestion 1972; 7: 129-38. 6. Walram S, Davis M, Nunnerley H, et al. Emergency endoscopy after gastrointestinal haemorrhage in 50 patients with portal hypertension. Br Med J 1974; 4: 94-96. 7. Terés J, Bordas JM, Bru C, Diaz F, Bruguera M, Rodes J. Upper gastrointestinal bleeding in cirrhosis: clinical and endoscopic correlation. Gut 1976; 17: 37-40. 8. Thomas E, Rosenthal WS, Rymer W, Katz D. Upper gastrointestinal hemorrhage in patients with alcoholic liver disease and esophageal varices. Am J Gastroenterol 1979; 72: 623-29. 9. Rector WG, Reynolds TB. Risk factors for haemorrhage from oesophageal varices and acute gastric erosions. Clin Gastroenterol 1985; 14: 139-53. 10. Perez-Ayuso RM, Piqué JM, Saperas E, at al. Gastric vascular ectasias in cirrhosis: association with hypoacidity not related to gastric atrophy. Scand J Gastroenterol 1989; 24: 1073-78. 11. Tarnawski AS, Sarfeh IJ, Stachura J, et al. Microvascular abnormalities of the portal hypertensive gastric mucosa. Hepatology 1988; 8: 1488-94. 12. Papazian A, Braillon A, Dupas JL, Sevenet F, Capron JP. Portal hypertensive gastric mucosa: an endoscopic study. Gut 1986; 27: 1199-203. 13. Quintero E, Piqué JM, Bombi JA, et al. Gastric mucosal vascular ectasias causing bleeding in cirrhosis. Gastroenterology 1987; 93: 1054-61. 14. Foster PN, Wyatt JI, Bullimore DW, Losowsky MS. Gastric mucosa in patients with portal hypertension: prevalence of capillary dilatation and Campylobacter pylori. J Clin Pathol 1989; 42: 919-21. 15. Hashizume M, Tanaka K, Mokuchi K. Morphology of gastric microcirculation in cirrhosis. Hepatology 1983; 6: 1008-12. 16. Benoit JN, Granger DN. Splanchnic haemodynamics in chronic portal hypertension. Sem Liv Dis 1986; 6: 287-98. 17. Kitano S, Koyanasi K, Sugimachi M, Kobayashi M, Inokuchi K. Mucosal blood flow and modified vascular responses to norepinephrine in the stomach of rats with liver cirrhosis. Surg Res 1982; 14: 221-30. 18. Piqué JM, Leung FW, Kitahora T, Sarfeh IJ, Tarnawski A, Guth PH. Gastric mucosal blood flow and acid secretion in portal hypertensive rats. Gastroenterology 1988; 95: 727-33. 19. Piqué JM, Pizcueta P, Perez-Ayuso RM, Bosch J. Effects of propanolol on gastric microcirculation and acid secretion in portal hypertensive rats. Hepatology 1990; 12: 476-80. 20. Benoit JN, Womack WA, Korthuis RJ, Wilborn WH, Granger DN. Chronic portal hypertension: effects on gastrointestinal flow distribution. Am J Physiol 1986; 250: G535-39. 21. Sarfeh IJ, Juler GL, Stemmer EA, et al. Results of surgical management of hemorrhagic gastritis in patients with gastro-esophageal varices. Surg Gynecol Obstet 1982; 155: 167-70. 22. Kroeger RJ, Groszmann RJ. Effect of selective blockade of B2-adrenergic receptors on portal systemic hemodynamics in a portal hypertensive rat model. Gastroenterology 1985; 88: 896-900. 23. Quintero E, Piqué JM, Bombi JA, et al. Antral mucosal hyperaemia:
characterization of a portal hypertension-related syndrome causing gastric bleeding in patients with cirrhosis. J Hepatol 1985; 1 (suppl): S315. 24. Hosking SW, Kennedy HJ, Seddon I, Triger DR. The role of propranolol in congestive gastropathy of portal hypertension. Hepatology 1987; 7: 437-41.
Laryngeal mask airway mask has been described as the missing link between the facemask and the endotracheal tube. It consists of a tubular oropharyngeal airway, to the distal end of which is The
laryngeal
attached a sealed, forward-pointing mask with an inflatable peripheral cuff. This apparatus is designed to produce an airtight seal around the laryngeal inlet and so provide a secure airway suitable for spontaneous or controlled ventilation. In most cases the laryngeal mask can be inserted easily without laryngoscopy; a muscle relaxant is seldom required. Once in place the device gives better and more secure airway control than the facemask; and there is no need to support the patient’s chin.l Consequently, the anaesthetist’s hands are freed, and remote observation of the patient may be possible when tracheal intubation would otherwise be essential.Scavenging of waste anaesthetic gases is as effective from laryngeal masks as from tracheal tubes3 and the device is also well tolerated during recovery from anaesthesia.4 Fibreoptic bronchoscopes passed down laryngeal masks have been used to observe the functioning of the vocal cords, an examination not possible during endotracheal anaesthesia.5,6 Thus it is not surprising that the laryngeal mask has quickly been adopted into anaesthetic practice and many applications have been reported. What is the proper place of this device in airway management? The endotracheal tube is the gold standard by which all other methods of airway control are judged. Once in position it provides a secure airway that facilitates easy ventilation and prevents aspiration of
regurgitated gastric contents. The laryngeal mask is easy
to position and use whereas tracheal intubation is a skilled procedure. Moreover, anatomical or pathological anomalies make tracheal intubation impossible in certain patients, even for experienced personnel. The laryngeal mask has been used successfully in patients of all ages in whom tracheal intubation had proved impossible.7-9 The mask can itself be used as an aid to difficult intubation- a small cuffed endotracheal tube10 or a gum-elastic bougiell(used to railroad an endotracheal tube into the position after removal of the laryngeal mask) can be passed into the trachea through correctly placed size 3 and 4 laryngeal masks. The use of the device in obstetric patients who have proved impossible to intubate is controversial. When learning to do obstetric anaesthesia, all anaesthetists are taught a failed intubation drill-maintenance of cricoid pressure (to prevent aspiration) and, if necessary, turning the patient onto her side head down and ventilating her with 100% oxygen until she awakes. In
1047
exceptional circumstances of extreme fetal distress, inhalation agent when the patient is on her side, head down, may be entertained to continue the operation but normal teaching would be to wake the patient. The priority is to keep the mother alive by making sure oxygen gets to her lungs, but sometimes the airway becomes completely obstructed and will remain so until the short-acting muscle relaxant, given to facilitate intubation, wears off. In these circumstances a laryngeal mask may allow an airway to be maintained and thus prevent hypoxia. Sometimes laryngeal masks have saved lives, so it has been suggested that the mask is an essential item wherever obstetric anaesthesia is practised.12 Patients with laryngeal spasm13 and inadequate reversal of neuromuscular blockade14 have likewise been successfully treated. The laryngeal mask may itself cause airway obstruction. Total obstruction occurs after insertion in 1 % and partial obstruction is seen in about 10% of adultsis and 19% of children.16 Displacement of the epiglottis or aryepiglottic folds by the mask seems to be the main cause; occasionally the epiglottis may become trapped between the pliable grates on the anterior surface of the device.17 Overall, the mask provides a satisfactory airway in 96-98% ofpatients16 and airway patency does not deteriorate during the course of anaesthesia.111 Nevertheless, when surgical procedures or patient position make airway security paramount, a tracheal tube should be used. Leakage of gas at the seal between the mask and the larynx when ventilator pressures exceed 1-7-2-0 kPa18 limits the usefulness of the device for controlled ventilation in patients with high inflation pressures. Unlike the tracheal tube the laryngeal mask does not prevent aspiration of gastric contents silent aspiration19 and aspiration pneumonia have been reported. 20 In a fibreoptic study, the oesophagus could be seen via the laryngeal mask in 3 of 50 patients examined. 15 Regurgitation of dye following preoperative ingestion of methylene blue capsules was compared in patients breathing spontaneously via a facemask and Guedel airway (a curved airway that reaches as far as the back of the tongue) or via a laryngeal mask. There was no regurgitation in patients breathing via the facemask whereas one-third of those using the laryngeal mask showed evidence of contamination.21 A possible explanation is that the pharyngeal response to insertion of the laryngeal mask resembles that to a bolus of food; part of this response is to allow relaxation of the lower oesophaeal sphincter and consequent regurgitation. The laryngeal mask airway may also trap gastric contents below it, making contamination of the airways more likely.19 Cardiovascular stress responses to insertion of laryngeal masks are similar but less pronounced than those seen during endotracheal intubation.22 Trauma to the uvula23 and pharyngeal tonsilsz4 has been reported, although such risks are slight with good insertion technique. 26 7% of patients complain
mask anaesthesia with
an
of postoperative sore throat vs 50% after tracheal intubation.26 The laryngeal mask can be inserted and used by unskilled personnel. Davies et a127 showed that Royal Navy medical trainees could successfully place and use the mask in 94% of cases vs 51% with tracheal tubes. Similar results were found when the laryngeal mask was used in a military field hospital,28 Even among ambulancemen who have received extended training, only 61 % can achieve an 80% success rate with tracheal intubation.29 Nevertheless, use of the lamygeal masks in emergencies is likely to be limited by their failure to prevent gastric aspiration. 1. Sarma VJ. The use of a laryngeal mask airway in spontaneously breathing patients. Acta Anaesthesiol Scand 1990; 34: 669-72. 2. Taylor DH, Child CS. The laryngeal mask for radiotherapy in children. Anaesthesia 1990; 45: 690. 3. Sarma VJ, Leman J. Laryngeal mask and anaesthetic waste gas concentrations. Anaesthesia 1990; 45: 791-92. 4. Maltby JR, Loken RG, Watson NC. Clinical appraisal of the laryngeal mask airway. Can J Anaesth 1990; 37: S108. 5. Akhtar TM. Laryngeal mask airway and visualisation of vocal cords during thyroid surgery. Can J Anaesth 1991; 38: 140. 6. McNamee CJ, Meyns B, Pagliero KM. Flexible bronchoscopy via the laryngeal mask. Thorax 1991; 46: 141-42. 7. Denny NM, Desilva KD, Webber PA. Laryngeal mask airway for emergency tracheostomy in a neonate. Anaesthesia 1990; 45: 895. 8. Allen JG, Flower EA. The brain laryngeal mask. An alternative to difficult intubation. Br Dental J 1990; 168: 202-04. 9. McClune S, Regan M, Moore J. Laryngeal mask airway for caesarean section. Anaesthesia 1990; 45: 227-28. 10. Brain AJ. Further developments of the laryngeal mask. Anaesthesia 1990; 44: 530. 11. Allison A, McCrory J. Tracheal placement of a gum elastic bougie using the laryngeal mask airways. Anaesthesia 1990; 45: 419-20. 12. De Mello WF, Kocan M, McClune S, Moore JA. The laryngeal mask in failed intubation. Anaesthesia 1990; 45: 689-90. 13. Michel MZ, Stubbing JF. Laryngeal mask airway and laryngeal spasm. Anaesthesia 1991; 46: 71. 14. Kumar CM. Laryngeal mask airway for inadequate reversal. Anaesthesia 1990; 45: 792. 15. Payne J. The use of the fibreoptic laryngoscope to confirm the position of the laryngeal mask. Anaesthesia 1989; 44: 865. 16. Rowbottom SJ, Simpson DL, Grubb D. The laryngeal mask airway in children, a fibreoptic assessment of positioning. Anaesthesia 1991; 46: 489-91. 17. Miller AC, Bickler P. The laryngeal mask airway, an unusual complication. Anaesthesia 1991; 46: 659-60. 18. Brodrick PM, Webster NR, Nunn JF. The laryngeal mask airway. A study of 100 patients during spontaneous breathing. Anaesthesia 1989; 44: 238-41. 19. Cyna AM, MacLeod DM, Campbell JR, Criswell J, John R. The laryngeal mask: cautionary tales. Anaesthesia 1990; 45: 167-68. 20. Griffin RM, Hatcher IS. Aspiration pneumonia and the laryngeal mask airway. Anaesthesia 1990; 45: 1039-40. 21. Barker P, Murphy P, Langton JA, Rowbottam DJ. Regurgitation of gastric contents during general anaesthesia using the laryngeal mask airway. Anaesthetic Research Society meeting, Manchester, 1991. 22. Braude N, Clements EA, Hodges UM, Andrews BP. The pressor response and laryngeal mask insertion: a comparison with tracheal intubation. Anaesthesia 1989; 44: 551-54. 23. Lee JJ. Laryngeal mask and trauma to uvula. Anaesthesia 1989; 44: 1014-15. 24. Van Heerden PV, Kirrage D. Large tonsils and the laryngeal mask airway. Anaesthesia 1989; 44: 703. 25. Brain A. Proper technique for the insertion of the laryngeal mask. Anaesthesiology 1990; 73: 1053-54. 26. Alexander CA, Leach AB. Incidence of sore throats with the laryngeal mask. Anaesthesia 1989; 44: 791. 27. Davies PR, Tighe SQ, Greenslade GL, Evans GH. Laryngeal mask airway and tracheal tube insertion by unskilled personnel. Lancet 1990; 336: 977-79. 28. De Mello WF, Ward P. The use of the laryngeal mask airway in primary anaesthesia. Anaesthesia 1990; 45: 792-93. 29. Wilson ME. Assessing intravenous cannulation and tracheal intubation training. Anaesthesia 1991; 46: 578-79.
portal hypertensive rates,"21 it was logical to see whether beta-adrenergic antagonists were effective in severe gastric mucosal haemorrhage. Two small open studies have shown that propranolol stops such bleeding in almost all cases,23.24; in a randomised controlled trial in a larger number of patients the frequency of rebleeding was significantly reduced.1 The mechanism of the beneficial effect of propranolol is uncertain. There is no evidence yet that the long-term outcome of cirrhotic patients with severe portal hypertensive gastropathy, or those with bleeding varices, is improved by either surgery or beta-adrenergic blockade. 1.
Perez-Ayuso RM, Piqué JM, Bosch J, et al. Propanolol in prevention of recurrent bleeding from severe portal hypertensive gastropathy in cirrhosis. Lancet 1991; 337: 1431-34. TT, Sims J, Eyre-Brook I,
2. McCormack
hypertension: inflammatory gastritis
al. Gastric lesions in portal congestive gastropathy? Gut
et
or
1985; 26: 1226-32. 3.
Quintero E, Piqué JM, Bombi JA, et al. Upper gastrointestinal bleeding caused by gastroduodenal vascular malformations: incidence, diagnosis, and treatment. Dig Dis Sci 1986; 31: 897-905. 4. Dagradi AE, Mehler R, Tan DT, Stempien SJ. Sources of upper gastrointestinal bleeding in patients with liver cirrhosis and large esophagogastric varices. Am J Gastroenterol 1970; 54: 458-63. 5. Khodadoost J, Glass GBJ. Erosive gastritis and acute gastroduodenal ulcerations as source of upper gastrointestinal bleeding in liver cirrhosis. Digestion 1972; 7: 129-38. 6. Walram S, Davis M, Nunnerley H, et al. Emergency endoscopy after gastrointestinal haemorrhage in 50 patients with portal hypertension. Br Med J 1974; 4: 94-96. 7. Terés J, Bordas JM, Bru C, Diaz F, Bruguera M, Rodes J. Upper gastrointestinal bleeding in cirrhosis: clinical and endoscopic correlation. Gut 1976; 17: 37-40. 8. Thomas E, Rosenthal WS, Rymer W, Katz D. Upper gastrointestinal hemorrhage in patients with alcoholic liver disease and esophageal varices. Am J Gastroenterol 1979; 72: 623-29. 9. Rector WG, Reynolds TB. Risk factors for haemorrhage from oesophageal varices and acute gastric erosions. Clin Gastroenterol 1985; 14: 139-53. 10. Perez-Ayuso RM, Piqué JM, Saperas E, at al. Gastric vascular ectasias in cirrhosis: association with hypoacidity not related to gastric atrophy. Scand J Gastroenterol 1989; 24: 1073-78. 11. Tarnawski AS, Sarfeh IJ, Stachura J, et al. Microvascular abnormalities of the portal hypertensive gastric mucosa. Hepatology 1988; 8: 1488-94. 12. Papazian A, Braillon A, Dupas JL, Sevenet F, Capron JP. Portal hypertensive gastric mucosa: an endoscopic study. Gut 1986; 27: 1199-203. 13. Quintero E, Piqué JM, Bombi JA, et al. Gastric mucosal vascular ectasias causing bleeding in cirrhosis. Gastroenterology 1987; 93: 1054-61. 14. Foster PN, Wyatt JI, Bullimore DW, Losowsky MS. Gastric mucosa in patients with portal hypertension: prevalence of capillary dilatation and Campylobacter pylori. J Clin Pathol 1989; 42: 919-21. 15. Hashizume M, Tanaka K, Mokuchi K. Morphology of gastric microcirculation in cirrhosis. Hepatology 1983; 6: 1008-12. 16. Benoit JN, Granger DN. Splanchnic haemodynamics in chronic portal hypertension. Sem Liv Dis 1986; 6: 287-98. 17. Kitano S, Koyanasi K, Sugimachi M, Kobayashi M, Inokuchi K. Mucosal blood flow and modified vascular responses to norepinephrine in the stomach of rats with liver cirrhosis. Surg Res 1982; 14: 221-30. 18. Piqué JM, Leung FW, Kitahora T, Sarfeh IJ, Tarnawski A, Guth PH. Gastric mucosal blood flow and acid secretion in portal hypertensive rats. Gastroenterology 1988; 95: 727-33. 19. Piqué JM, Pizcueta P, Perez-Ayuso RM, Bosch J. Effects of propanolol on gastric microcirculation and acid secretion in portal hypertensive rats. Hepatology 1990; 12: 476-80. 20. Benoit JN, Womack WA, Korthuis RJ, Wilborn WH, Granger DN. Chronic portal hypertension: effects on gastrointestinal flow distribution. Am J Physiol 1986; 250: G535-39. 21. Sarfeh IJ, Juler GL, Stemmer EA, et al. Results of surgical management of hemorrhagic gastritis in patients with gastro-esophageal varices. Surg Gynecol Obstet 1982; 155: 167-70. 22. Kroeger RJ, Groszmann RJ. Effect of selective blockade of B2-adrenergic receptors on portal systemic hemodynamics in a portal hypertensive rat model. Gastroenterology 1985; 88: 896-900. 23. Quintero E, Piqué JM, Bombi JA, et al. Antral mucosal hyperaemia:
characterization of a portal hypertension-related syndrome causing gastric bleeding in patients with cirrhosis. J Hepatol 1985; 1 (suppl): S315. 24. Hosking SW, Kennedy HJ, Seddon I, Triger DR. The role of propranolol in congestive gastropathy of portal hypertension. Hepatology 1987; 7: 437-41.
Laryngeal mask airway mask has been described as the missing link between the facemask and the endotracheal tube. It consists of a tubular oropharyngeal airway, to the distal end of which is The
laryngeal
attached a sealed, forward-pointing mask with an inflatable peripheral cuff. This apparatus is designed to produce an airtight seal around the laryngeal inlet and so provide a secure airway suitable for spontaneous or controlled ventilation. In most cases the laryngeal mask can be inserted easily without laryngoscopy; a muscle relaxant is seldom required. Once in place the device gives better and more secure airway control than the facemask; and there is no need to support the patient’s chin.l Consequently, the anaesthetist’s hands are freed, and remote observation of the patient may be possible when tracheal intubation would otherwise be essential.Scavenging of waste anaesthetic gases is as effective from laryngeal masks as from tracheal tubes3 and the device is also well tolerated during recovery from anaesthesia.4 Fibreoptic bronchoscopes passed down laryngeal masks have been used to observe the functioning of the vocal cords, an examination not possible during endotracheal anaesthesia.5,6 Thus it is not surprising that the laryngeal mask has quickly been adopted into anaesthetic practice and many applications have been reported. What is the proper place of this device in airway management? The endotracheal tube is the gold standard by which all other methods of airway control are judged. Once in position it provides a secure airway that facilitates easy ventilation and prevents aspiration of
regurgitated gastric contents. The laryngeal mask is easy
to position and use whereas tracheal intubation is a skilled procedure. Moreover, anatomical or pathological anomalies make tracheal intubation impossible in certain patients, even for experienced personnel. The laryngeal mask has been used successfully in patients of all ages in whom tracheal intubation had proved impossible.7-9 The mask can itself be used as an aid to difficult intubation- a small cuffed endotracheal tube10 or a gum-elastic bougiell(used to railroad an endotracheal tube into the position after removal of the laryngeal mask) can be passed into the trachea through correctly placed size 3 and 4 laryngeal masks. The use of the device in obstetric patients who have proved impossible to intubate is controversial. When learning to do obstetric anaesthesia, all anaesthetists are taught a failed intubation drill-maintenance of cricoid pressure (to prevent aspiration) and, if necessary, turning the patient onto her side head down and ventilating her with 100% oxygen until she awakes. In
1047
exceptional circumstances of extreme fetal distress, inhalation agent when the patient is on her side, head down, may be entertained to continue the operation but normal teaching would be to wake the patient. The priority is to keep the mother alive by making sure oxygen gets to her lungs, but sometimes the airway becomes completely obstructed and will remain so until the short-acting muscle relaxant, given to facilitate intubation, wears off. In these circumstances a laryngeal mask may allow an airway to be maintained and thus prevent hypoxia. Sometimes laryngeal masks have saved lives, so it has been suggested that the mask is an essential item wherever obstetric anaesthesia is practised.12 Patients with laryngeal spasm13 and inadequate reversal of neuromuscular blockade14 have likewise been successfully treated. The laryngeal mask may itself cause airway obstruction. Total obstruction occurs after insertion in 1 % and partial obstruction is seen in about 10% of adultsis and 19% of children.16 Displacement of the epiglottis or aryepiglottic folds by the mask seems to be the main cause; occasionally the epiglottis may become trapped between the pliable grates on the anterior surface of the device.17 Overall, the mask provides a satisfactory airway in 96-98% ofpatients16 and airway patency does not deteriorate during the course of anaesthesia.111 Nevertheless, when surgical procedures or patient position make airway security paramount, a tracheal tube should be used. Leakage of gas at the seal between the mask and the larynx when ventilator pressures exceed 1-7-2-0 kPa18 limits the usefulness of the device for controlled ventilation in patients with high inflation pressures. Unlike the tracheal tube the laryngeal mask does not prevent aspiration of gastric contents silent aspiration19 and aspiration pneumonia have been reported. 20 In a fibreoptic study, the oesophagus could be seen via the laryngeal mask in 3 of 50 patients examined. 15 Regurgitation of dye following preoperative ingestion of methylene blue capsules was compared in patients breathing spontaneously via a facemask and Guedel airway (a curved airway that reaches as far as the back of the tongue) or via a laryngeal mask. There was no regurgitation in patients breathing via the facemask whereas one-third of those using the laryngeal mask showed evidence of contamination.21 A possible explanation is that the pharyngeal response to insertion of the laryngeal mask resembles that to a bolus of food; part of this response is to allow relaxation of the lower oesophaeal sphincter and consequent regurgitation. The laryngeal mask airway may also trap gastric contents below it, making contamination of the airways more likely.19 Cardiovascular stress responses to insertion of laryngeal masks are similar but less pronounced than those seen during endotracheal intubation.22 Trauma to the uvula23 and pharyngeal tonsilsz4 has been reported, although such risks are slight with good insertion technique. 26 7% of patients complain
mask anaesthesia with
an
of postoperative sore throat vs 50% after tracheal intubation.26 The laryngeal mask can be inserted and used by unskilled personnel. Davies et a127 showed that Royal Navy medical trainees could successfully place and use the mask in 94% of cases vs 51% with tracheal tubes. Similar results were found when the laryngeal mask was used in a military field hospital,28 Even among ambulancemen who have received extended training, only 61 % can achieve an 80% success rate with tracheal intubation.29 Nevertheless, use of the lamygeal masks in emergencies is likely to be limited by their failure to prevent gastric aspiration. 1. Sarma VJ. The use of a laryngeal mask airway in spontaneously breathing patients. Acta Anaesthesiol Scand 1990; 34: 669-72. 2. Taylor DH, Child CS. The laryngeal mask for radiotherapy in children. Anaesthesia 1990; 45: 690. 3. Sarma VJ, Leman J. Laryngeal mask and anaesthetic waste gas concentrations. Anaesthesia 1990; 45: 791-92. 4. Maltby JR, Loken RG, Watson NC. Clinical appraisal of the laryngeal mask airway. Can J Anaesth 1990; 37: S108. 5. Akhtar TM. Laryngeal mask airway and visualisation of vocal cords during thyroid surgery. Can J Anaesth 1991; 38: 140. 6. McNamee CJ, Meyns B, Pagliero KM. Flexible bronchoscopy via the laryngeal mask. Thorax 1991; 46: 141-42. 7. Denny NM, Desilva KD, Webber PA. Laryngeal mask airway for emergency tracheostomy in a neonate. Anaesthesia 1990; 45: 895. 8. Allen JG, Flower EA. The brain laryngeal mask. An alternative to difficult intubation. Br Dental J 1990; 168: 202-04. 9. McClune S, Regan M, Moore J. Laryngeal mask airway for caesarean section. Anaesthesia 1990; 45: 227-28. 10. Brain AJ. Further developments of the laryngeal mask. Anaesthesia 1990; 44: 530. 11. Allison A, McCrory J. Tracheal placement of a gum elastic bougie using the laryngeal mask airways. Anaesthesia 1990; 45: 419-20. 12. De Mello WF, Kocan M, McClune S, Moore JA. The laryngeal mask in failed intubation. Anaesthesia 1990; 45: 689-90. 13. Michel MZ, Stubbing JF. Laryngeal mask airway and laryngeal spasm. Anaesthesia 1991; 46: 71. 14. Kumar CM. Laryngeal mask airway for inadequate reversal. Anaesthesia 1990; 45: 792. 15. Payne J. The use of the fibreoptic laryngoscope to confirm the position of the laryngeal mask. Anaesthesia 1989; 44: 865. 16. Rowbottom SJ, Simpson DL, Grubb D. The laryngeal mask airway in children, a fibreoptic assessment of positioning. Anaesthesia 1991; 46: 489-91. 17. Miller AC, Bickler P. The laryngeal mask airway, an unusual complication. Anaesthesia 1991; 46: 659-60. 18. Brodrick PM, Webster NR, Nunn JF. The laryngeal mask airway. A study of 100 patients during spontaneous breathing. Anaesthesia 1989; 44: 238-41. 19. Cyna AM, MacLeod DM, Campbell JR, Criswell J, John R. The laryngeal mask: cautionary tales. Anaesthesia 1990; 45: 167-68. 20. Griffin RM, Hatcher IS. Aspiration pneumonia and the laryngeal mask airway. Anaesthesia 1990; 45: 1039-40. 21. Barker P, Murphy P, Langton JA, Rowbottam DJ. Regurgitation of gastric contents during general anaesthesia using the laryngeal mask airway. Anaesthetic Research Society meeting, Manchester, 1991. 22. Braude N, Clements EA, Hodges UM, Andrews BP. The pressor response and laryngeal mask insertion: a comparison with tracheal intubation. Anaesthesia 1989; 44: 551-54. 23. Lee JJ. Laryngeal mask and trauma to uvula. Anaesthesia 1989; 44: 1014-15. 24. Van Heerden PV, Kirrage D. Large tonsils and the laryngeal mask airway. Anaesthesia 1989; 44: 703. 25. Brain A. Proper technique for the insertion of the laryngeal mask. Anaesthesiology 1990; 73: 1053-54. 26. Alexander CA, Leach AB. Incidence of sore throats with the laryngeal mask. Anaesthesia 1989; 44: 791. 27. Davies PR, Tighe SQ, Greenslade GL, Evans GH. Laryngeal mask airway and tracheal tube insertion by unskilled personnel. Lancet 1990; 336: 977-79. 28. De Mello WF, Ward P. The use of the laryngeal mask airway in primary anaesthesia. Anaesthesia 1990; 45: 792-93. 29. Wilson ME. Assessing intravenous cannulation and tracheal intubation training. Anaesthesia 1991; 46: 578-79.
