Efficacy and safety of the laryngeal mask airwayvs Guedel airway following tracheal extubation

PURPOSE: To compare the safety and efficacy of the laryngeal mask airway (LMA) with the Guedel airway during the recovery period. METHODS: In a prospective randomised trial in the Post Anesthesia Care Unit (PACU), 52 patients (ASA 1 and 2) were randomised to receive either a laryngeal mask airway (LMA: n = 26) or a Guedel airway (n = 26) during the recovery period after middle ear surgery. Ease of airway maintenance was graded and the presence of coughing was noted. Peripheral arterial oxygen saturation (SpO2) was measured continuously by pulse oximetry in the PACU. Readings were taken on arrival (time 0) and for five minutes afterwards. RESULTS: There was no difference in sex, age, weight or incidence of smoking between the two groups. In the LMA group 25 patients required no airway manipulation and only one patient required repositioning of the LMA. In the Guedel group severe difficulty maintaining the airway was experienced in two patients, moderate difficulty in five patients and mild difficulty in 12 patients. Seven patients required no airway manipulation. The LMA group showed higher ease of airway maintenance scores, (P = < 0.0001) and less coughing (P = 0.0496). At time 0 and at one minute the LMA group had higher median SpO2 (97% and 97%) than the Guedel group (95% and 96%), (P = 0.0002 and 0.0362). There was no further difference in SpO2. CONCLUSIONS: The LMA provides easier airway maintenance, less coughing and initially higher median SpO2 when compared with the Guedel airway in the recovery period.     

The laryngeal mask airway. Safety, efficacy, and current use

In 1983, the laryngeal mask airway (LMA) was introduced as a new airway device. It can be inserted without the aid of a laryngoscope or neuromuscular blockade. Compared with the face mask, the LMA allows for a more "hands-free approach" to airway management providing the anesthesiologist the freedom of not holding a mask. In addition, the LMA is more effective than the face mask, with or without a Guedel airway, during emergency resuscitation in situations where endotracheal intubation is difficult or not possible. The LMA seems to provide better oxygenation than the face mask; but unlike the endotracheal tube, it does not protect the airway from aspiration of gastric contents if regurgitation occurs. For this reason, it is believed that the LMA should not be used in place of an endotracheal tube during emergency rescue, but rather as an adjunct to airway management prior to intubation. It is possible that the risk of regurgitation with or without aspiration may be minimized if proper screening of patients is employed prior to use of the LMA. The current literature concerning its safety and efficacy is reviewed.     

The ProSeal laryngeal mask airway: A randomized, crossover study with the standard laryngeal mask airway in paralyzed, anesthetized patients

BACKGROUND: The ProSeal laryngeal mask airway (PLMA) is a new laryngeal mask device with a modified cuff to improve seal and a drainage tube to provide a channel for regurgitated fluid and gastric tube placement. In the present randomized, crossover study, the authors tested the hypothesis that ease of insertion, airway sealing pressure, and fiberoptic position differ between the PLMA and the standard laryngeal mask airway (LMA). For the PLMA, we also assess ease of gastric tube placement and the efficacy of an introducer tool. METHODS: Sixty paralyzed, anesthetized adult patients were studied. Both devices (only size 4) were inserted into each patient in random order. Airway sealing pressure and fiberoptic position were determined during cuff inflation from 0 to 40 ml in 10-ml increments. Gastric tube insertion was attempted with the PLMA if there was no gas leak from the drainage tube. In 60 additional patients, ease of insertion for the PLMA was compared with and without an introducer. RESULTS: First-time success rates were higher (60 of 60 vs. 52 of 60; P = 0.003) and the effective airway time shorter (9 +/- 3 s vs20 +/- 18 s; P < 0.0001) for the LMA. There were no failed uses of either device within three attempts. Airway sealing pressure was 8-11 cm H2O higher for the PLMA at all cuff volumes (P < 0.00001) and was higher in females for both devices. Fiberoptic position was better with the LMA at all cuff volumes (P < 0.00001), but vocal cord visibility was similar (LMA, 59 of 60; PLMA, 56 of 60). For the PLMA, gastric tube placement was successful in 58 of 58 patients and took 9 +/- 5 s. First-time success rates were higher (59 of 60 vs53/60; P = 0.03) and the effective airway time shorter (15 +/- 13 s vs 23 +/- 18 s; P = 0.008) with the introducer. CONCLUSION: The PLMA is capable of achieving a more effective seal than the LMA and facilitates gastric tube placement, but it is more difficult to insert unless an introducer tool is used. When correctly positioned, the PLMA isolates the glottis from the upper esophagus with possible implications for airway protection.     

The ProSeal Laryngeal Mask Airway: A Randomized, Crossover Study with the Standard Laryngeal Mask Airway in Paralyzed, Anesthetized Patients

Background: The ProSeal laryngeal mask airway (PLMA) is a new laryngeal mask device with a modified cuff to improve seal and a drainage tube to provide a channel for regurgitated fluid and gastric tube placement. In the present randomized, crossover study, the authors tested the hypothesis that ease of insertion, airway sealing pressure, and fiberoptic position differ between the PLMA and the standard laryngeal mask airway (LMA). For the PLMA, we also assess ease of gastric tube placement and the efficacy of an introducer tool.

Methods: Sixty paralyzed, anesthetized adult patients were studied. Both devices (only size 4) were inserted into each patient in random order. Airway sealing pressure and fiberoptic position were determined during cuff inflation from 0 to 40 ml in 10-ml increments. Gastric tube insertion was attempted with the PLMA if there was no gas leak from the drainage tube. In 60 additional patients, ease of insertion for the PLMA was compared with and without an introducer.

Results: First-time success rates were higher (60 of 60 vs. 52 of 60;P = 0.003) and the effective airway time shorter (9 +/- 3 s vs 20 +/- 18 s;P < 0.0001) for the LMA. There were no failed uses of either device within three attempts. Airway sealing pressure was 8-11 cm H2O higher for the PLMA at all cuff volumes (P < 0.00001) and was higher in females for both devices. Fiberoptic position was better with the LMA at all cuff volumes (P < 0.00001), but vocal cord visibility was similar (LMA, 59 of 60; PLMA, 56 of 60). For the PLMA, gastric tube placement was successful in 58 of 58 patients and took 9 +/- 5 s. First-time success rates were higher (59 of 60 vs 53/60;P = 0.03) and the effective airway time shorter (15 +/- 13 s vs 23 +/- 18 s;P = 0.008) with the introducer.     

A multicenter study comparing the ProSeal and Classic laryngeal mask airway in anesthetized, nonparalyzed patients

BACKGROUND: The laryngeal mask airway ProSeal (PLMA), a new laryngeal mask device, was compared with the laryngeal mask airway Classic (LMA) with respect to: (1) insertion success rates and times; (2) efficacy of seal; (3) fiberoptically determined anatomic position; (4) orogastric tube insertion success rates and times; (5) total intraoperative complications; and (6) postoperative sore throat in nonparalyzed adult patients undergoing general anesthesia, hypothesizing that these would be different. METHODS: Three hundred eighty-four nonparalyzed anesthetized adult patients (American Society of Anesthesiologists physical status I-II) were randomly allocated to the PLMA or LMA for airway management. In addition, 50% of patients were randomized for orogastric tube placement. Unblinded observers collected intraoperative data, and blinded observers collected postoperative data. RESULTS: First-attempt insertion success rates (91 vs. 82%, P = 0.015) were higher for the LMA, but after three attempts success rates were similar (LMA, 100%; PLMA, 98%). Less time was required to achieve an effective airway with the LMA (31 +/- 30 vs. 41 +/- 49 s; P = 0.02). The PLMA formed a more effective seal (27 +/- 7 vs. 22 +/- 6 cm H2O; P < 0.0001). Fiberoptically determined anatomic position was better with the LMA (P < 0.0001). Orogastric tube insertion was more successful after two attempts (88 vs. 55%; P < 0.0001) and quicker (22 +/- 18 vs. 38 +/- 56 s) with the PLMA. During maintenance, the PLMA failed twice (leak, stridor) and the LMA failed once (laryngospasm). Total intraoperative complications were similar for both groups. The incidence of postoperative sore throat was similar. CONCLUSION: In anesthetized, nonparalyzed patients, the LMA is easier and quicker to insert, but the PLMA forms a better seal and facilitates easier and quicker orogastric tube placement. The incidence of total intraoperative complications and postoperative sore throat are similar.     

Routine use of the intubating laryngeal mask airway results in increased upper airway morbidity

PURPOSE: The classic laryngeal mask airway (LMA) has a soft, silicone tube and the intubating laryngeal mask airway (ILM) has a rigid, silicone-coated steel tube. We compare postoperative pharyngolaryngeal morbidity in patients randomised to receive either device. METHODS: Sixty-five female patients (ASA physical status class I or II, aged 18-80 yr) undergoing balanced regional anesthesia for gynecological laparotomy expected to last one to two hours were randomly assigned for airway management with the LMA or ILM. Intracuff pressure was maintained at 60 cm H20. Postoperative pharyngolaryngeal morbidity (sore throat, difficulty swallowing, sore mouth, sore neck/jaw, hoarseness) was assessed at two, 24 and 48 hr by blinded investigators. RESULTS: The number of insertion attempts and duration of anesthesia was similar between groups. Sore throat was more common for the ILM at two hours (44 vs 15%, P=0.01), 24 hr (59 vs 21%, P=0.008) and 48 hr (34 vs 3%, P=0.005). Sore mouth was more common for the ILM at two hours (16 vs 0%, P=0.02) and 24 hr (12 vs 0%, P=0.04), but not at 48 hr (6 vs 3%). Difficulty swallowing was more common for the ILM at two hours (25 vs 0%, P=0.04), but not at 24 hr (31 vs 3%) and 48 hr (12 vs 9%). There were no differences in the incidence of sore jaw/neck (ILM, 3-12%; LMA, 0-3%) and hoarseness (ILM, 12-31%; LMA, 16-18%). There was no correlation between postoperative pharyngolaryngeal morbidity and duration of anesthesia. CONCLUSION: Pharyngolaryngeal morbidity is more common with the ILM than the LMA following anesthesia lasting one to two hours.     

Œdème pulmonaire aigu par inhalation du cale-dents au réveil d’une anesthésie avec un masque laryngéPulmonary oedema due to the inhalation of the LMA bite-block during recovery.

We report a case of acute pulmonary oedema, consecutive to upper airway obstruction due to the inhalation of the laryngeal mask airway (LMA) bite block during recovery. The LMA was used for general anaesthesia with the bite-block provided in France. No trouble occurred during LMA insertion and anaesthesia. Symptomatic treatment provided complete resolution within a few days.     

Acute pulmonary edema from inhalation of the bite-block after anesthesia with a laryngeal mask]

We report a case of acute pulmonary oedema, consecutive to upper airway obstruction due to the inhalation of the laryngeal mask airway (LMA) bite block during recovery. The LMA was used for general anaesthesia with the bite-block provided in France. No trouble occurred during LMA insertion and anaesthesia. Symptomatic treatment provided complete resolution within a few days.     

A Multicenter Study Comparing the ProSealTM and ClassicTM Laryngeal Mask Airway in Anesthetized, Nonparalyzed Patients

Background: The laryngeal mask airway ProSeal(TM) (PLMA(TM)), a new laryngeal mask device, was compared with the laryngeal mask airway Classic(TM) (LMA(TM)) with respect to: (1) insertion success rates and times; (2) efficacy of seal; (3) fiberoptically determined anatomic position; (4) orogastric tube insertion success rates and times; (5) total intraoperative complications; and (6) postoperative sore throat in nonparalyzed adult patients undergoing general anesthesia, hypothesizing that these would be different.

Methods: Three hundred eighty-four nonparalyzed anesthetized adult patients (American Society of Anesthesiologists physical status I-II) were randomly allocated to the PLMA(TM) or LMA(TM) for airway management. In addition, 50% of patients were randomized for orogastric tube placement. Unblinded observers collected intraoperative data, and blinded observers collected postoperative data.

Results: First-attempt insertion success rates (91 vs. 82%, P = 0.015) were higher for the LMA(TM), but after three attempts success rates were similar (LMA(TM), 100%;PLMA(TM), 98%). Less time was required to achieve an effective airway with the LMA(TM) (31 +/- 30 vs. 41 +/- 49 s;P = 0.02). The PLMA(TM) formed a more effective seal (27 +/- 7 vs. 22 +/- 6 cm H2O;P < 0.0001). Fiberoptically determined anatomic position was better with the LMA(TM) (P < 0.0001). Orogastric tube insertion was more successful after two attempts (88 vs. 55%;P < 0.0001) and quicker (22 +/- 18 vs. 38 +/- 56 s) with the PLMA(TM). During maintenance, the PLMA(TM) failed twice (leak, stridor) and the LMA(TM) failed once (laryngospasm). Total intraoperative complications were similar for both groups. The incidence of postoperative sore throat was similar.     

COMPARISON OF THE USE OF THE LARYNGEAL MASK AND FACE MASK BY INEXPERIENCED PERSONNEL

Ten junior doctors with no postgraduate anaesthetic experienceattempted to ventilate the lungs of 50 anaesthetized patients,using either a laryngeal mask or a Guedel airway and face mask.Success was defined as the production of two successive tidalvolumes exceeding 800 ml within 40 s. The failure rate was significantlygreater using the laryngeal mask compared with the face mask(P < 0.05) and the average time was significantly longerwith the laryngeal mask than with the face mask (P < 0.01). The results from this investigation suggest the laryngealmask airway cannot be recommended as a resuscitation devicefor use by inexperienced operators.     

Supraglottic airway devices

Supraglottic airway devices are developed with increasing frequency following the overwhelming success of the laryngeal mask airway (LMA). In contrast to the first generation devices such as the 'classic' LMA and the laryngeal tube second generation devices usually offer an oesophageal drainage tube and/or an improved oropharyngeal leak pressure during positive pressure ventilation such as the laryngeal mask ProSeal and the laryngeal tube S. Recently the disposable versions of these supraglottic airway devices and the novel I-Gel mask have gained increasing interest. Both the LMA and the PLMA have been shown to be perfectly suitable for routine anaesthesia and emergency airway management. While the lacking protection against aspiration is still considered a major limitation of the LMA, the value of airway devices with an oesophageal drainage tube in this respect remains untermined at present.     

A Randomized Controlled Trial Comparing the Cuffed Oropharyngeal Airway and the Laryngeal Mask Airway in Spontaneously Breathing Anesthetized Adults

Background: The cuffed oropharyngeal airway (COPA), a modified Guedel airway, was compared with the laryngeal mask airway (LMA) during spontaneous breathing anesthesia. Specifically examined were ease of use, physiologic tolerance, and the frequency of problems.

Methods: Adult patients consented to random (2:1) assignment to either COPA (n = 302) or LMA (n = 151) for airway management during anesthesia with propofol, nitrous oxide, and oxygen.

Results: Ease of insertion was similar, but the first-time successful insertion rate was higher with the LMA (COPA, 81% compared with LMA, 89%; P = 0.05). More brief manipulations (head tilt, chin lift, jaw thrust) were reported in the COPA group (average total number of manipulations: COPA, 1.1 +/- 1.6 compared with LMA, 0.1 +/- 0.2; P <0.001). Continuous airway support was used more frequently in the COPA group (COPA, 30% compared with LMA, 0%; P < 0.0005). The incidences of aspiration, regurgitation, laryngospasm, wheezing, succinylcholine administration, oxygen saturation (SpO2) < 92%, failed use, and minor intraoperative problems were similar. When the airways were removed, blood was detected on the COPA less frequently than on the LMA (COPA, 5.8% compared with LMA, 15.3%; P = 0.001). The incidence of early and late sore throat was greater with the LMA (early: COPA, 4.7% compared with LMA, 21.9% [P = 0.001]; late: COPA, 8.4% compared with LMA, 16.1%; P = 0.01). The LMA did better than the COPA when anesthetists analyzed the technical aspects of the two devices.     

Failed obstetric tracheal intubation and postoperative respiratory support with the ProSeal laryngeal mask airway

The ProSeal laryngeal mask airway (ProSeal LMA) provides a better seal and probably better airway protection than the classic laryngeal mask airway (classic LMA). We report the use of the ProSeal LMA in a 26-yr-old female with HELLP syndrome for failed obstetric intubation and postoperative respiratory support. Both laryngoscope-guided tracheal intubation and face mask ventilation failed, but a size 4 ProSeal LMA was easily inserted and high tidal volumes obtained. A gastric tube was inserted through the ProSeal LMA drain tube and 300 mL of clear fluid was removed from the stomach. There were no hemodynamic changes during ProSeal LMA insertion. Postoperatively, the patient was transferred to the intensive care unit, where she was ventilated via the ProSeal LMA for 8 h until the platelet count had increased and she was hemodynamically stable. Weaning and ProSeal LMA removal were uneventful. There is anecdotal evidence supporting the use of the LMA devices for failed obstetric intubation (19 cases) and for postoperative respiratory support (8 cases). In principle, the ProSeal LMA may offer some advantages over the classic LMA in both these situations. IMPLICATIONS: We report the successful use of the ProSeal laryngeal mask airway for failed obstetric intubation and postoperative respiratory support in a patient with HELLP syndrome.     

SLIPA喉罩对腹腔镜胆囊切除术围拔管期躁动及血流动力学的影响

目的 比较腹腔镜胆囊切除术应用SLIPA喉罩和气管导管行全麻通气对拔管期躁动及血流动力学的影响.方法 将腹腔镜胆囊切除术患者60例随机分为喉罩组和气管导管组,每组30例.两组患者均用咪达唑仑+异丙酚+舒芬太尼+顺式阿曲库铵静脉诱导,麻醉诱导后喉罩组插入SLIPA喉罩,气管导管组插入气管导管.比较两组患者拔管期血流动力学变化、躁动评分及不良反应发生例数.结果 喉罩组躁动评分显著低于气管导管组(P<0.05),两组患者血流动力学变化差异有统计学意义(P<0 05);气管导管组苏醒后30 min自诉喉部不适例数多于喉罩组(P<0 05).结论 全麻下腹腔镜胆囊切除术采用SLIPA喉罩通气比气管插管通气在拔管期循环动力学更稳定,患者耐受程度好,安全有效.     

Comparison of the reinforced laryngeal mask airway and tracheal intubation for nasal surgery

Airway maintenance and protection during anaesthesia and recovery provided by the reinforced laryngeal mask airway was compared with the sequential use of a tracheal tube followed by the Guedel airway in 66 patients having anaesthesia for nasal surgery. One patient was withdrawn from the laryngeal mask group because the airway was difficult to position. All patients had an oropharyngeal pack inserted and Moffett's solution instilled into the nasal cavities. At the end of surgery the nasal cavities were packed. During operation airway maintenance was good and airway protection was equally effective in both groups. Contamination of the lower airway occurred in only five patients. During recovery from anaesthesia the laryngeal mask and Guedel airway were well tolerated by most patients, but only the mask laryngeal provided an unobstructed airway in all patients. The laryngeal mask protects the larynx from contamination during and after operation until the return of the patient's own protective reflexes.     

Laryngeal mask vs intubating laryngeal mask: insertion and ventilation by inexperienced resuscitators.

The laryngeal mask airway (LMA) has been shown to be useful in airway maintenance during resuscitation. The intubating laryngeal mask (ILM) is a modified LMA permitting both ventilation and rapid endotracheal intubation. We aimed to compare the LMA and the ILM with regard to ease of insertion and successful ventilation by inexperienced personnel. We have used anaesthetized, apnoeic, non-paralysed patients as a model to simulate resuscitation. Following standardized training, non-anaesthetic medical staff with no previous experience in laryngeal mask airway insertion (novices) inserted either the LMA or ILM in 55 patients following induction of anaesthesia. There were no differences between the two patient groups included in our study with regard to mean age and body mass index (BMI). The success rate for inserting the airway device and achieving a significant end-tidal CO2 recording within two minutes was 23/28 for the LMA (82.1%) and 22/27 for the ILM (81.5%). Reasons for failure included inability to insert the ILM past the teeth and insertion of the LMA upside down. There were no clinically relevant differences in the mean time to airway insertion and successful ventilation (62.6 vs 62 seconds) or expired tidal volume (781 vs 767 ml) for the LMA and ILM respectively. We conclude that the ILM is as easily inserted and effectively used as an LMA by novices and, because it allows the option offacilitating endotracheal intubation, may be the preferred device for maintaining an airway during resuscitation.     

Comparison of sevoflurane with propofol for laryngeal mask airway insertion in adults

We performed a prospective, randomized, controlled trial to compare the quality and ease of laryngeal mask airway (LMA) insertion after either rapid inhaled sevoflurane or i.v. propofol induction of anesthesia. Seventy-six unpremedicated ASA physical status I or II patients were anesthetized with either a single vital capacity breath of sevoflurane 8% or i.v. propofol 3 mg/kg, which produced equally rapid loss of consciousness (40.5 +/- 13.9 vs 37.7 +/- 9.9 s; P > 0.05). The LMA was inserted more rapidly in patients in the propofol group (74 +/- 29 vs 127 +/- 35 s; P < 0.01) and required fewer attempts (1.2 vs 1.6; P < 0.05) than the sevoflurane group. There was a greater incidence of initially impossible mouth opening in the sevoflurane group (45% vs 21%; P < 0.05). Once mouth opening was possible, the degree of attenuation of laryngeal reflexes was similar. The overall incidence of complications related to LMA insertion, especially apnea (32% vs 0%; P < 0.01), was more frequent in the propofol group (82% vs 26%; P < 0.01). There were four failures of LMA insertion in the propofol group and none in the sevoflurane group. Both groups had stable hemodynamic profiles and good patient satisfaction. We conclude that sevoflurane vital capacity breath induction compares favorably with i.v. propofol induction for LMA insertion in adults. However, prolonged jaw tightness after the sevoflurane induction of anesthesia may delay LMA insertion. Implications: In this randomized, controlled trial, we compared the ease of insertion of the laryngeal mask airway in adults after induction of anesthesia with either a sevoflurane vital capacity breath technique or propofol i.v.. We conclude that sevoflurane compares favorably with propofol, although prolonged jaw tightness may delay laryngeal mask airway insertion.     

Supraglottic airway devices

Supraglottic airway devices are developed with increasing frequency following the overwhelming success of the laryngeal mask airway (LMA). Currently, the LMA, the ProSeal laryngeal mask airway (PLMA), the laryngeal tube (LT), the laryngeal tube with integrated suctioning tube (LTS) and the oesophageal tracheal combitube (OTC) are the best evaluated and most widespread devices. Both the LMA and the PLMA have been shown to be perfectly suitable for routine anaesthesia and emergency airway management. While the LMA is limited by the lack of reliable protection against aspiration, the value of the PLMA in this respect remains undetermined yet. LT and LTS are primarily intended as emergency airway devices, but have also been successfully used during controlled ventilation in adults. The OTC, though advocated for emergency as well as routine use, is limited by high airway morbidity and possible serious complications.     

Continuous ventilation technique for laryngeal mask airway (LMA) removal after fiberoptic intubation in children

BACKGROUND: Fiberoptic tracheal intubation through the laryngeal mask airway (LMA) is a simple technique to establish a safe airway in neonates and infants with a difficult airway. The technique, however, is complicated by the removal of the laryngeal mask from the patient's mouth because of the similarity in length of the LMA and the tracheal tube. METHODS: Several solutions have been presented to stabilize the tracheal tube within the trachea during withdrawal of the LMA. With all these techniques ventilation of the patient is interrupted. RESULTS: We present a modified technique, using a double tube assembly, which allows uninterrupted ventilation of the patient during withdrawal of the LMA from the patient's mouth. CONCLUSIONS: The technique is simple and safe, can be performed without hurry and carries potential advantages for neonates and children with limited cardiorespiratory reserve.     

Gastric distension and ventilation during laparoscopic cholecystectomy: LMA-classic vs. tracheal intubation

PURPOSE: The standard laryngeal mask airway LMA-Classic was designed as an alternative to the endotracheal tube (ETT) or the face mask for use with either spontaneous or positive pressure ventilation. Positive pressure ventilation may exploit leaks around the LMA cuff, leading to gastric distension and/or inadequate ventilation. We compared gastric distension and ventilation parameters with LMA vs ETT during laparoscopic cholecystectomy. METHODS: One hundred and one, ASA I-II adults scheduled for elective laparoscopic cholecystectomy were randomly assigned to LMA-Classic or ETT. Patients with BMI >30 kg x m(-2), hiatus hernia or gastroesophageal reflux were excluded. Following induction of anesthesia, an in-and-out orogastric tube was passed to decompress the stomach before insertion of the LMA (women size #4, men size #5) or ETT (women 7 mm, men 8 mm). Anesthesia was maintained with isoflurane in nitrous oxide and oxygen (FIO2 0.3-0.5), rocuronium and fentanyl. The surgeon, blinded to the type of airway, scored gastric distention 0-10 at insertion of the laparoscope and immediately before removal at the end of the surgical procedure. RESULTS: Incidence and degree of change in gastric distension were similar in both groups. Ventilation parameters during insufflation (mean +/- SD) for LMA and ETT were: S(P)O2 98 +/- I vs 98 +/- I, P(ET)CO2 38 +/- 4 vs 36 +/- 4 mm Hg and airway pressure 21 +/- 4 vs 23 +/- 3 cm water. CONCLUSION: Positive pressure ventilation with a correctly placed LMA-Classic of appropriate size permits adequate pulmonary ventilation. Gastric distension occurs with equal frequency with either airway device.