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PubMed2002

A comparison of the laryngeal tube with the laryngeal mask airway during routine surgical procedures.

UNLABELLED: The laryngeal mask airway (LMA; Laryngeal Mask Company, Henley-on-Thames, UK) is an established airway device, whereas the laryngeal tube (LT) is relatively new and therefore not as well investigated. Therefore, the purpose of the present prospective, randomized, controlled trial was to compare the LT with the LMA in routine clinical practice. In 50 patients undergoing general anesthesia for minor routine surgery, standardized anesthesia was induced and maintained with alfentanil and propofol. Patients were randomized to controlled ventilation (fraction of inspired oxygen = 0.4; fraction of inspired nitrous oxide = 0.6; tidal volume = 7 mL/kg; respiratory rate = 10 breaths/min) with the LT (n = 25) or the LMA (n = 25). Oxygen saturation was recorded before the induction of anesthesia and after the administration of oxygen. After 2 and 10 min of ventilation with the LT or LMA, oxygen saturation, end-expiratory carbon dioxide, expiratory tidal volume, and peak airway pressure were recorded. Capillary blood gas samples were taken before the induction of anesthesia and after 10 min of ventilation. Time of insertion and airway leak pressure of each device were measured. The time of insertion was comparable with both devices (LT versus LMA, median 21 s versus 19 s; P = not significant). Blood gas samples and ventilation variables revealed sufficient ventilation and oxygenation with either device (P = not significant). Peak airway pressure (LT, 17 +/- 3 cm H(2)O; LMA, 15 +/- 3 cm H(2)O) and airway leak pressure (LT, 36 +/- 3 cm H(2)O; LMA, 22 +/- 3 cm H(2)O) were significantly (P < 0.05) higher when using the LT compared with the LMA. In conclusion, using the LT and LMA resulted in comparable ventilation and oxygenation variables in this model of ASA physical status I and II patients undergoing routine surgical procedures. The newly developed LT may be a simple alternative device to secure the airway. IMPLICATIONS: The laryngeal tube, a newly developed airway device, and the laryngeal mask airway were used to ventilate patients in the operating room. Both airway devices proved to be effective and safe; however, the laryngeal tube allowed greater airway pressure during ventilation.

Adolescent↗
PubMed2001

Comparison of the intubating laryngeal mask airway with the fiberoptic intubation in anticipated difficult airway management.

BACKGROUND: The intubating laryngeal mask airway (ILMA; Fastrach; Laryngeal Mask Company, Henley-on-Thames, UK) may provide an alternative technique to fiberoptic intubation (FIB) to facilitate the management of the anticipated difficult airway. The authors therefore compared the effectiveness of the ILMA with FIB in patients with anticipated difficult intubation. METHODS: One hundred patients, with at least one difficult intubation criteria (Mallampati class III or IV, thyromental distance < 65 mm, interincisor distance < 35 mm) were enrolled (FIB group, n = 49; ILMA group, n = 51) in this prospective randomized study. Anesthesia was induced with propofol and maintained with alfentanil and propofol after an efficient mask ventilation has been demonstrated. The success of the technique (within three attempts), the number of attempts, duration of the successful attempt, and adverse events (oxygen saturation < 90%, bleeding) were recorded. RESULTS: The rate of successful tracheal intubation with ILMA was 94% and comparable with FIB (92%). The number of attempts and the time to succeed were not significantly different between groups. In case of failure of the first technique, the alternative technique always succeeded. Failures in FIB group were related to oxygen desaturation (oxygen saturation < 90%) and bleeding, and to previous cervical radiotherapy in the ILMA group. Adverse events occurred significantly more frequently in FIB group than in ILMA group (18 vs. 0%, P < 0.05). CONCLUSION: The authors obtained a high success rate and comparable duration of tracheal intubation with ILMA and FIB techniques. In patients with previous cervical radiotherapy, the use of ILMA cannot be recommended. Nevertheless, the use of the ILMA was associated with fewer adverse events.

Adult↗
PubMed2002

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.

Adolescent↗
PubMed2004

Gum elastic bougie-guided insertion of the ProSeal laryngeal mask airway is superior to the digital and introducer tool techniques.

BACKGROUND: The authors compare three techniques for insertion of the ProSeal laryngeal mask airway. METHODS: Two hundred forty healthy patients aged 18-80 yr were randomly allocated for ProSeal laryngeal mask airway insertion using the digital, introducer tool (IT), or gum elastic bougie (GEB)-guided techniques. The digital and IT techniques were performed according to the manufacturer's instructions. The GEB-guided technique involved priming the drain tube with the GEB, placing the GEB in the esophagus under direct vision, and inserting the ProSeal laryngeal mask airway using the digital technique with the GEB as a guide. Failed insertion was defined by any of the following criteria: (1) failed pharyngeal placement; (2) malposition (air leaks, negative tap test results, or failed gastric tube insertion if pharyngeal placement was successful); and (3) ineffective ventilation (maximum expired tidal volume < 8 ml/kg or end-tidal carbon dioxide > 45 mmHg if correctly positioned). Any visible or occult blood was noted. Sore throat, dysphonia, and dysphagia were assessed 18-24 h postoperatively. RESULTS: Insertion was more frequently successful with the GEB-guided technique at the first attempt (GEB, 100%; digital, 88%; IT, 84%; both P < 0.001), but success after three attempts was similar (GEB, 100%; digital, 99%; IT, 98%). The time taken to successful placement was similar among groups at the first attempt but was shorter for the GEB-technique after three attempts (GEB, 25 +/- 14 s; digital, 33 +/- 19 s; IT, 37 +/- 25 s; both: P < 0.003). There were no differences in the frequency of visible blood, but occult blood occurred less frequently with the GEB-guided technique (GEB, 12%; digital, 29%; IT, 31%; both: P < 0.02) but was similar among techniques if insertion was successful at the first attempt. There were no differences in postoperative airway morbidity. CONCLUSION The GEB-guided insertion technique is more frequently successful than the digital or IT techniques. The authors suggest that the GEB-guided technique may be a useful backup technique for when the digital and IT techniques fail.

Adolescent↗
PubMed2004

A randomized controlled trial comparing the ProSeal Laryngeal Mask Airway with the Laryngeal Tube Suction in mechanically ventilated patients.

BACKGROUND: The ProSeal Laryngeal Mask Airway (PLMA) (Laryngeal Mask Company, Henley-on-Thames, United Kingdom) is a new laryngeal mask with a modified cuff designed to improve its seal and a drain tube for gastric tube placement. Similarly, the Laryngeal Tube Suction (LTS) (VBM Medizintechnik Gmbh, Sulz a.N, Germany) is a new laryngeal tube that also has an additional channel for gastric tube placement. This study compared the placement and functions of these two devices. METHODS: One hundred fifty patients undergoing general anesthesia for elective surgery were randomly allocated to the PLMA (n = 75) or LTS (n = 75). Oxygenation and ventilation, ease of insertion, fiberoptic view, oropharyngeal leak pressure, ventilatory data, ease of gastric tube insertion, and postoperative airway morbidity were determined. RESULTS: After successful insertion of the devices in 96% of patients with the PLMA and in 94.4% with the LTS it was possible to maintain oxygenation, ventilation, and respiratory mechanics during the entire duration of surgery. Successful first and second attempt insertion rates were 57 patients (76%) and 15 patients (20%), respectively, for the PLMA and 60 patients (80%) and 11 patients (14.6%), respectively, for the LTS. Airway placement was unsuccessful with the PLMA in three patients and with the LTS in four patients. Time to achieve an effective airway was 36 +/- 24 s with the PLMA versus 34 +/- 25 s with the LTS. Gastric tube insertion was possible in 97.3% of patients with the PLMA and in 96% with the LTS. CONCLUSIONS: With respect to both physiologic and clinical function, the PLMA and LTS are similar and either device can be used to establish a safe and effective airway in mechanically ventilated anesthetized adult patients.

Adult↗
PubMed2005

Laryngeal reflex before and after placement of airway interventions: endotracheal tube and laryngeal mask airway.

BACKGROUND: Previous reports indicate that detrimental laryngeal function persists over several hours after tracheal extubation even in patients who have regained full consciousness from anesthesia. The authors hypothesize that even after minor surgery, the presence of an endotracheal tube (ETT) impairs the receptors at the vocal cord and diminishes the defensive laryngeal function. The hypothesis was tested by comparing types of experimentally induced laryngeal airway reflexes before and after surgery in anesthetized patients with use of either an ETT or a Laryngeal Mask Airway. METHODS: Twenty adult patients undergoing elective minor surgeries were randomly allocated into two groups, the ETT and Laryngeal Mask Airway groups, depending on the airway management method used during surgery. While maintaining sevoflurane at 1 minimum alveolar concentration, laryngeal and respiratory responses were elicited by instillation of distilled water on the vocal cords immediately before and after surgery. Furthermore, the vocal cord angles were endoscopically measured under complete paralysis. RESULTS: Some laryngeal reflex responses of both groups, particularly the cough reflex, were significantly attenuated after minor surgery. Significant narrowing of the glottic aperture was evident in patients with ETT placement but not in patients with Laryngeal Mask Airway placement. CONCLUSIONS: With either airway intervention, laryngeal defensive reflexes are depressed immediately after surgery even without visible laryngeal swelling. The sensory impairment attributable to the presence of an ETT cannot be the solo factor responsible for the modification of the defensive airway reflexes elicited from the larynx.

Adult↗
PubMed2006

Alfentanil dosage when inserting the classic laryngeal mask airway.

BACKGROUND: The purpose of this study was to determine an optimum dose of alfentanil, coadministered with 2.5 mg/kg propofol, when inserting a classic laryngeal mask airway. METHODS: Seventy-five adult ethnic Chinese patients with an American Society of Anesthesiologists physiologic status classification I or II and requiring anesthesia for minor surgery with a laryngeal mask were recruited. They were randomly assigned to five dosage groups: placebo or 5, 10, 15, or 20 microg/kg. The study drug plus propofol were administered, and 90 s later, insertion conditions were assessed using a six-category score. The duration of apnea was recorded. A probit analysis was performed and used to estimate the ED50 and ED95 with 95% confidence intervals for each assessment. RESULTS: Twenty-five male and 50 female patients, aged 18-59 yr, were studied. The five groups were similar. Laryngeal mask insertion was successful in all but one alfentanil patient. Duration of apnea increased with increasing dosage of alfentanil to over 5 min (P < 0.001). Dose-responses could not be predicted for categories of resistance to mouth opening and to insertion. For the other four categories, swallowing, gagging, movement, and laryngospasm, ED50 and ED95 with confidence intervals for alfentanil could be determined. CONCLUSION: The optimum dose for alfentanil, when coadministered with 2.5 mg/kg propofol, was 10 microg/kg.

Adolescent↗
PubMed2006

Incidence and predictors of difficult and impossible mask ventilation.

BACKGROUND: Mask ventilation is an essential element of airway management that has rarely been studied as the primary outcome. The authors sought to determine the incidence and predictors of difficult and impossible mask ventilation. METHODS: A four-point scale to grade difficulty in performing mask ventilation (MV) is used at the authors' institution. They used a prospective, observational study to identify cases of grade 3 MV (inadequate, unstable, or requiring two providers), grade 4 MV (impossible to ventilate), and difficult intubation. Univariate and multivariate analyses of a variety of patient history and physical examination characteristics were used to establish risk factors for grade 3 and 4 MV. RESULTS: During a 24-month period, 22,660 attempts at MV were recorded. 313 cases (1.4%) of grade 3 MV, 37 cases (0.16%) of grade 4 MV, and 84 cases (0.37%) of grade 3 or 4 MV and difficult intubation were observed. Body mass index of 30 kg/m or greater, a beard, Mallampati classification III or IV, age of 57 yr or older, severely limited jaw protrusion, and snoring were identified as independent predictors for grade 3 MV. Snoring and thyromental distance of less than 6 cm were independent predictors for grade 4 MV. Limited or severely limited mandibular protrusion, abnormal neck anatomy, sleep apnea, snoring, and body mass index of 30 kg/m or greater were independent predictors of grade 3 or 4 MV and difficult intubation. CONCLUSIONS: The authors observed the incidence of grade 3 MV to be 1.4%, similar to studies with the same definition of difficult MV. Presence of a beard is the only easily modifiable independent risk factor for difficult MV. The mandibular protrusion test may be an essential element of the airway examination.

Adult↗
PubMed1985

Prevention of gastric inflation during mask ventilation in newborn infants.

Ten premature infants who had recovered from the respiratory distress syndrome were subjected to cricoid compression during mask ventilation. Each infant was ventilated with an AMBU face mask for 3 min with the nasogastric (NG) tube, without the NG tube, and without the NG tube but applying cricoid pressure during ventilation. The results of the study indicated that, similar to insertion of an NG tube, cricoid compression can prevent gastric inflation during mask ventilation.

Cricoid Cartilage↗
PubMedDate not supplied

Influence of contralateral masking on bone-conduction thresholds.

Two studies were conducted using normal-hearing listeners. In study 1, bone-conduction (BC) thresholds were obtained with contralateral masking at an effective level (EL) of 30 and 35 dB. In study 2, the EL of the contralateral masking equaled the magnitude of the occlusion effect (OE) plus a safety factor of 10 and 20 dB. Within each study, BC threshold shifts were evident at the higher compared with the lower ELs. Between studies, the highest BC thresholds were always obtained in the presence of the highest SPL of the masker which occurred in the 35 dB EL condition, whereas the lowest BC thresholds were always obtained in the presence of the lowest SPL of the masker which occurred in the OE + 10 dB condition. Even though the BC thresholds were influenced by the amount of contralateral masking, the BC thresholds obtained in each study were in good agreement with the new ANSI S3.26-1981 BC reference thresholds.

Adult↗
PubMed1999

Unmasked thresholds and minimum masking in infants and adults: separating sensory from nonsensory contributions to infant-adult differences in behavioral thresholds.

OBJECTIVE: The purposes were to determine the degree to which infant unmasked thresholds differed from those of adults, to determine the effect of signal frequency on those differences, and to determine whether there is a difference in minimum effective masking as a function of age and frequency. The data were applied to a model to address the question of the origin (sensory versus nonsensory) of infant-adult differences in behavioral unmasked thresholds. DESIGN: Infant behavioral thresholds in quiet and in noise for pure tones of 0.5 and 2 kHz were measured using computer-based visual reinforcement audiometry. Adult thresholds were measured using the same apparatus and a modified conventional audiometric procedure. Twenty-three infants and 24 adults were included in the analyses. The masked thresholds versus masker intensity data were used to estimate minimum masking levels (MMLs). RESULTS: Group mean unmasked thresholds of infants were greater than those of adults at both frequencies and the difference was greater at 0.5 kHz (14.2 dB) than at 2 kHz (5.5 dB). Infant MMLs were greater than those of adults by 10.1 dB at 0.5 kHz and by 1.2 dB at 2 kHz. The fact that a masker had to be 10.1 dB greater in intensity for infants than for adults at 0.5 kHz and 1.2 dB greater at 2 kHz suggests that there is a difference in sensitivity between the groups of about 10 and 1 dB for the two frequencies, respectively. According to a proposed model, the difference between infants and adults in MMLs is less than the difference in unmasked thresholds owing to the influence of nonsensory factors that bias infant unmasked thresholds. Such factors, therefore, contribute 4.1 dB (i.e., 14.2 dB-10.1 dB) at 0.5 kHz and 4.3 dB (i.e., 5.5 dB-1.2 dB) at 2 kHz based on the data. CONCLUSIONS: The infant-adult differences in unmasked thresholds, with greater difference at 0.5 kHz than at 2 kHz, are consistent with earlier research on infant hearing. The data reveal that the greater difference between infants and adults at 0.5 kHz relative to 2 kHz is not a result of nonsensory factors alone, but is largely due to a difference in sensory processing. Only about 4 dB of the difference between infants and adults in unmasked thresholds can be attributed to nonsensory factors and the effect is not frequency specific according to the proposed model. Consideration of establishing audiometric reference values for infants that are different than those based on adults, owing to the elevated behavioral unmasked thresholds of normal-hearing infants, is suggested.

Adult↗
PubMed1984

The use of a backward masking paradigm to assess information-processing deficits among schizotypics. A re-evaluation of Steronko and Woods.

In 1978, Steronko and Woods (J. Abnorm. Psychol., 87: 481-490, 1978) failed to find significant differences in early visual information processing between "schizotypic" and "psychiatric control" college students, as identified by the MMPI; yet these authors concluded that schizotypics suffer from information-processing deficits. The present study was designed to extend and clarify these findings by modifying the methods and procedures used by these researchers. A visual backward masking task was employed to study the information processing of individuals whose MMPI-168 profiles indicated schizophrenic tendencies in the absence of an obvious thought disorder. These schizotypic individuals were identified by the MMPI 2-7-8 code type and were compared with three other groups, also identified by their MMPI profiles: an "inflation-free" control group, an "other-inflations" control group, and a group with an 8-9/9-8 MMPI code type. The 8-9/9-8 code type has been associated with psychotic features in adolescents and adults. Two dependent measures were evaluated: critical stimulus duration in a no-mask condition and mean target identification as a function of varying interstimulus intervals. The 2-7-8 group had significantly higher critical stimulus duration values than either the inflation-free group or the 8-9 groups. The 2-7-8 group and the 8-9 groups had fewer correct identifications of target stimuli than either the inflation-free group or the other-inflations group. These results suggest that both the 2-7-8 group and the 8-9 group may be more vulnerable to the effects of the masking stimulus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1999

Use of the laryngeal mask airway in otologic surgery.

OBJECTIVE/HYPOTHESIS: The combination of intravenous sedation and local infiltration anesthesia is routinely utilized in otologic surgery. Advantages over general anesthesia with endotracheal intubation include ease and speed of induction and emergence, safety, and decreased postoperative discomfort. Anatomic and physiological patient constraints may preclude the use of intravenous sedation and anesthetists inexperienced in this technique may find it difficult to achieve a consistent level of anesthesia appropriate for major otologic surgery. Administration of anesthesia using the laryngeal mask airway (LMA) has been proposed to offer many of the advantages of intravenous sedation with less risk of oversedation and obstructive apnea. STUDY DESIGN: A retrospective chart review. METHODS: A review of 100 consecutive adult and pediatric patients undergoing major otologic procedures in which the LMA was utilized. RESULTS: All laryngeal masks were introduced without a laryngoscope and successful placement was accomplished on the first attempt in 98%. Procedures were performed under spontaneous ventilation and in only one instance was surgery temporarily interrupted because of patient movement. No major complications occurred and no patients required endotracheal intubation. Only three patients complained of mild throat discomfort in the immediate postoperative period. CONCLUSIONS: The laryngeal mask airway is a safe and effective means of providing anesthesia during major otologic surgery.

Adolescent↗
PubMed2002

Time course of masking in spatial resolution tasks.

PURPOSE: Further evidence is presented that Landolt C acuity has an integration time extending over several hundred milliseconds, well beyond the Bunsen-Roscoe-Bloch critical duration within which the intensity-time reciprocity for visual thresholds holds. METHODS: To test whether all segments of a longer exposure contribute equally to the uptake of acuity information, the acuity impairment caused by short-duration masking stimuli was measured for a range of onset asynchronies. RESULTS: A 50-ms mask impairs resolution most when it is presented 50 to 100 ms after the onset of the target, and it no longer influences acuity when shown 50 ms after its extinction. CONCLUSION: Allowing for the well-established optimally-effective test-mask asynchrony of 50 ms or so, the results permit the conclusion that whereas acuity information is assimilated during the whole exposure of a target, the first 50 ms are more effective, and this fits with the initial peaking of impulse activity of neurons in the primate visual cortex to flashed visual stimuli.

Humans↗
PubMed1996

The laryngeal mask airway: a review for the emergency physician.

The laryngeal mask airway has recently been released as a adjunct to airway management. It has gained widespread acceptance as an alternative to the face mask for the provision of general anesthesia. The LMA is available in various sizes for use in every age and weight patient (Table 1). Each LMA costs roughly $200, but they can be sterilized and reused numerous times. The skills required for its successful use can be easily learned, and successful placement can be expected in up to 90% of cases with little or no practice. While it is used frequently in the operating room as a replacement for the anesthesia mask, its role outside of the operating room may include an adjunct in the management of the difficult airway. In this setting it may be used as a guide to blind endotracheal intubation or for fiberoptic-guided intubation. More importantly, it may be life-saving in the cannot intubate/cannot ventilate scenario.

Anesthesia, General↗
PubMed2004

Efficacy of the A-line AEP monitor as a tool for predicting successful insertion of a laryngeal mask during sevoflurane anesthesia.

BACKGROUND: The use of clinical signs for assessing depth of anesthesia is unreliable during periods with little noxious stimulation. A patient may appear adequately anesthetized at one moment at a given level of stimulation, but may later, when facing other more intense stimuli, show signs of insufficient anesthesia. In order to prevent under- or overdosing of anesthetics, an anesthesia depth monitor that is able to predict responses to noxious stimulation would therefore be useful. Auditory evoked potentials (AEP) is one of several physiological parameters under investigation. The method has been improved by rapid extraction and conversion of the AEP curve into an index (A-Line ARX Index = AAI). We aimed to determine the clinically required depth of anesthesia, measured by the A-line AEP Monitor, for at least 90% probability of acceptable insertion conditions for a laryngeal mask airway (LMA). METHODS: We studied 112 patients anesthetized by mask with increasing concentration of sevoflurane in oxygen. The monitor was programmed to give an alarm at AAI between 15 and 40 according to randomization. When the alarm sounded, the end-expiratory sevoflurane concentration was recorded and the LMA inserted. Insertion conditions were assessed by an observer blinded to the AAI. RESULTS: The ED(95) and prediction probability (P(K)) for AAI were 14.5 (CI 7.4-21.6) and 0.76 (0.66-0.86), respectively, while the ED(95) and P(K) for expiratory sevoflurane concentration were 4.36% (CI 3.73-4.98) and 0.95 (0.91-0.99). CONCLUSIONS: AAI indicates the level of depth of anesthesia necessary for acceptable laryngeal mask insertion conditions. End-expiratory sevoflurane concentration was the better predictor.

Adult↗
PubMed1990

The laryngeal mask airway in children.

The laryngeal mask airway was used in 200 children during a variety of surgical procedures. Some problem with the use of the device was encountered in 47 cases (23%), but in only five cases (2.5%) were the problems serious enough to warrant abandonment of its use. A clear airway was ultimately achieved in 191 children. Downfolding of the epiglottis over the laryngeal inlet was identified in eight out of 24 patients where flexible laryngoscopy was performed, clinically all these had unobstructed airways. The mask was used in 16 children with known airway problems. It is concluded that the size 2 laryngeal mask airway can be successfully used within the weight range 6-30 kg.

Airway Obstruction↗
PubMed1991

Airway protection by the laryngeal mask. A barrier to dye placed in the pharynx.

Methylene blue was placed in the pharynx of 64 patients undergoing anaesthesia with the laryngeal mask. No leak of dye into the larynx was detected on fibreoptic inspection of the inside of the mask in any subject. The use of the laryngeal mask as a means of protecting the airway during procedures such as minor nasal operations is therefore supported.

Airway Obstruction↗