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.     

First clinical impressions of ProSeal laryngeal mask

ProSeal laryngeal mask airway (PLMA, LMA-ProSeal) is a newly developed laryngeal mask airway intended to overcome two major disadvantages of the conventional laryngeal mask airway, i.e., poor protection of the airway from gastric regurgitation and low sealing effect around the laryngeal inlet. The new PLMA can provide air-tight sealing by a second cuff positioned at the back of the mask and a bypass channel for the alimentary tract by a second tube (drain tube) opening at the tip of the mask. However, clinical feature of this new device has been assessed by few authors. Forty adult patients (19 males and 21 females) under general anesthesia immobilized with vecuronium were included in this study. A PLMA size 4 was inserted with (n = 10) or without (n = 30) an introducer at first (n = 37), second (n = 2) or third (n = 1) attempt and clear airway was obtained in all patients. After placing the PLMA in 10 patients (5 males and 5 females) sealing pressure was measured at cuff pressure of 0, 20, 40 and 60 cmH2O and at completely deflated cuff state. Averaged seal pressure at the 60 cm H2O cuff pressure was 22.7 +/- 8.0 cmH2O in the all 40 patients. Averaged seal pressure was higher in female than in male at all cuff pressure. The average seal pressure was 15.1 cmH2O even when the cuff was deflated completely. A lubricated 16-French gastric tube was inserted easily through the drain tube in all patients except one in which the mask was found to be deflected backward. There were no significant complications related to the PLMA. We concluded that the PLMA can provide high sealing pressure and isolate the airway from the alimentary tract. Further study including adverse effect of the high sealing effect should be required.     

Comparison of the Laryngeal Tube Suction and the Proseal laryngeal Mask Airway in anesthetized patients

BACKGROUND: The Laryngeal Tube Suction (LTS : Smith Medical, Tokyo) is a new laryngeal tube that has an additional channel for gastric tube placement. Similarly, the Proseal Laryngeal Mask Airway (PLMA) also has a drain tube for gastric tube placement. This study compared the functions of these two devices. METHODS: Forty patients undergoing general anesthesia were randomly allocated to the group LTS (n = 20) or group PLMA (n = 20). Ease of insertion, quality of airway seal, ease of gastric tube insertion, fiberoptic view of the glottis through each device after placement, and postoperative sorethroat/hoarseness were investigated. RESULTS: There were no differences in patient characteristics and anesthetic background data for both groups. No differences concerning handling, quality of airway seal, ease of gastric tube insertion, and postoperative airway morbidity were detected between LTS and PLMA. In economical terms, LTS was more reasonable compared with PLMA. CONCLUSIONS: With respect to clinical function, the LTS and PLMA were similar and either device can be used to establish an effective airway in anesthetized patients.     

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.     

A Randomized Controlled Trial Comparing the ProSeal™ Laryngeal Mask Airway with the Laryngeal Tube Suction in Mechanically Ventilated Patients

Background: The ProSeal(TM) 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.     

The proseal laryngeal mask: results of a descriptive trial with experience of 300 cases

Background. The ProSeal laryngeal mask airway (PLMA) is a newlaryngeal mask device with a modified cuff and a drainage tube. Methods. We assessed the PLMA in 300 anaesthetized adults eitherparalysed or breathing spontaneously. We assessed insertioncharacteristics, airway seal pressures, haemodynamic responseto insertion, ease of gastric tube placement, gastric insufflation,and postoperative sore throat. Results. Insertion was successful in 294 patients (98%) andgraded as easy in 274 patients (91%). We found no differencein ease of insertion or success rate with either the introduceror the finger insertion method, or in paralysed or non-paralysedpatients. Mean airway seal pressure was 29 cm H₂O, and 59 patients(20%) had seal pressures greater than 40 cm H₂O. No gastricinsufflation was detected. Gastric tube placement was successfulin 290 of 294 patients (98.6%). There was no cardiovascularresponse to insertion, with a small reduction in heart rate5 min after insertion and significant decreases in mean arterialpressure at 1 and 5 min after insertion. Sore throat was notedin 23% patients after operation and in 16% of patients after24 h, with 90% of the sore throats described as mild. Conclusions. The PLMA is a reliable airway management devicethat can give an effective glottic seal in paralysed and non-paralysedpatients. The device allows the easy passage of a gastric tube,causes a minimal haemodynamic response to insertion, and anacceptable incidence of sore throat. Br J Anaesth 2002; 88: 534–9     

The ProSeal laryngeal mask airway: fibreoptic visualization of the glottic opening is associated with ease of insertion of the gastric tube

PURPOSE: To verify if correct ProSeal laryngeal mask airway (PLMA) placement may condition blind insertion of a gastric tube via the PLMA. METHODS: The PLMA was studied in 150 anesthetized patients using a size #4 in (females) and #5 in (males). Its position was determined by inserting a fibrescope in the airway tube. A lubricated gastric tube was inserted through the PLMA drainage tube, recording the number of attempts at insertion. The relationship between fibreoptic glottic visualization score and attempts at gastric tube insertion using the PLMA was tested statistically. RESULTS: Insertion success rate of the PLMA and of the gastric tube was 93.3% and 99.3%, respectively. Ventilation was satisfactory in all patients, irrespective of fibreoptic score value. A significant correlation (Spearman's rank correlation, P = 0.0186) was present between attempts at gastric tube insertion and fibreoptic score. CONCLUSION: Partial or total visualization of the vocal cords makes the success of gastric tube insertion more probable. Considering that fibreoptic visualization of the glottic aperture is associated with ease of insertion of a gastric tube (P < 0.02), the authors recommend adjusting or reinserting the PLMA if difficulty during the initial positioning of the gastric tube is experienced.     

The ProSeal laryngeal mask airway and the laryngeal tube Suction for ventilation in gynaecological patients undergoing laparoscopic surgery

BACKGROUND AND OBJECTIVE: ProSeal Laryngeal Mask Airway (PLMA) and Laryngeal Tube Suction (LTS), supraglottic airway devices allowing gastric drainage, were compared in this prospective, randomized study for airway management under conditions with elevated intra-abdominal pressure induced by capnoperitoneum. METHODS: Fifty patients undergoing elective gynaecological laparoscopic surgery were randomized to two groups of 25 each. After induction of general anaesthesia, devices were inserted, correct placement was verified, airway leak pressure was measured, and a gastric tube was inserted. Ease of insertion, quality of airway seal, risk of gastric insufflation and patient comfort were investigated. RESULTS: There were no differences in patient characteristics data for both groups. First-time insertion success rates were comparable for both groups: 92%--first attempt, 8%--second attempt for PLMA and LTS. Time until delivery of the first tidal volume for PLMA and LTS was 23.2 +/- 6.1 and 23.5 +/- 6.6s, airway leak pressure was 45.4 +/- 4.9 cmH2O and 45.6 +/- 6.7 cmH2O with cuff pressures adjusted to 60 cmH2O. No gastric insufflation, gas loss or signs of regurgitation were detected. Placement of a gastric tube was successful in all patients. Patients were questioned for sore throat and dysphagia after removal of devices. Sore throat was stated in 1%/0% (PLMA) and 8%/4% (LTS) after 6/24 h, dysphagia in 4%/4% (PLMA) and 12%/4% (LTS). CONCLUSIONS: Both devices provide a secure airway even under conditions of elevated intra-abdominal pressure. In this pilot study, no differences concerning handling or quality of airway seal were detected between PLMA and LTS.     

The size 1(1/2) ProSeal laryngeal mask airway in infants: a randomized, crossover investigation with the Classic laryngeal mask airway

Many problems with the Classic laryngeal mask airway (CLMA) in infants are believed to be related to its inadequate cuff design. One of the main limitations of the CLMA is that the resulting low-pressure seal can be inadequate for positive pressure ventilation (PPV). The ProSeal LMA (PLMA), a new laryngeal mask airway with a modified cuff, has been shown to form a more effective seal than the CLMA in children. The first infant size PLMA, size 1(1/2), became available recently. We studied 30 anesthetized, nonparalyzed infants aged 15 mo (2-30 mo) and weighing 9 kg (5-12 kg). The CLMA and PLMA were inserted in random order into each patient. Airway leak pressure and maximum tidal volume were measured. Ease of insertion, quality of initial airway, and fiberoptic position were also determined. Gastric tube placement was assessed for the PLMA. The mean airway leak pressure in neutral head position (26.7 versus 18.9 cm H2O), maximum flexion (35.6 versus 28.2 cm H2O), and the mean maximum tidal volume (312 versus 260 mL) were significantly higher for the PLMA (P < 0.01). Air entered the stomach in eight patients with the CLMA but did not with the PLMA. Gastric tube placement was possible in all but one patient. In three patients, the use of the PLMA led to some degree of clinically relevant compression of the larynx. The size 1(1/2) PLMA seems to be a more suitable device for airway maintenance in infants than the same size CLMA. The ability to insert a gastric tube at the same time, and a significantly higher airway leak pressure than with the CLMA, may have important implications for its use for PPV in infants.     

The proseal™laryngeal mask airway: a review of the literature

PURPOSE: To analyze and summarize the published literature relating to the ProSeal LMA (PLMA): a modification of the "classic LMA" (cLMA) with an esophageal drain tube (DT), designed to improve controlled ventilation, airway protection and diagnosis of misplacement. SOURCE: Articles identified through Medline and EMBASE searches using keywords "Proseal", "ProSeal" and "PLMA". Hand searches of these articles and major anesthetic journals from January 1998 to March 2005. PRINCIPAL FINDINGS: Searches identified 59 randomized controlled trials or clinical studies and 79 other publications. Compared to the cLMA, PLMA insertion takes a few seconds longer. First attempt insertion success for the PLMA is lower, but overall success is equivalent. Airway seal is improved by 50%. The DT enables early diagnosis of mask misplacement, allows gastric drainage, reduces gastric inflation and may vent regurgitated stomach contents. Evidence suggests, but does not prove, that the correctly placed PLMA reduces aspiration risk compared with the cLMA. PLMA use is associated with less coughing and less hemodynamic disturbance than use of a tracheal tube (TT). Comparative trials of the PLMA with other supraglottic airways favour the PLMA. Clinicians have extended the use of the PLMA inside and outside the operating theatre including use for difficult airway management and airway rescue. CONCLUSIONS: The PLMA has similar insertion characteristics and complications to other laryngeal masks. The DT enables rapid diagnosis of misplacement. The PLMA offers significant benefits over both the cLMA and TT in some clinical circumstances. These and clinical experience with the PLMA are discussed.     

A randomized study to compare ProSeal laryngeal mask airway with classic laryngeal mask airway in anesthetized patients

BackgroundTo overcome the problem of gastric content regurgitation, a device with drain tube and better airway sealing has been made: the ProSeal laryngeal mask airway (PLMA). We aimed to compare the clinical performance of the classic LMA with the PLMA. Several studies comparing these two devices have been done.Our study was designed to compare ease of insertion, airway sealing pressure, and fiber-optic assessment of positioning in adult patients, and we hopes to prove that PLMA is better to LMA in all these aspects. We hypothesized that PLMA would have a better leak pressure than the CLMA and minimum difference in leak pressure of 20% between them was considered clinically significant.Material and methodsOne hundred adult patients of either sex between age group of 18–65 years scheduled for elective surgery were included in the study. Patients were randomly allocated to two groups of 50 patients each. In group I CLMA and in group II PLMA were used. The number of attempts, ease of insertion, time of insertion, and failure if occurred were noted down. Hemodynamic changes, airway sealing pressure, and the fiber-optic were also recorded.ResultsData thus compiled showed that insertion was successful in first attempt in 94% cases with LMA as well as PLMA. The time taken for successful placement of LMA and - PLMA was 15 and 17 s, respectively. Sealing pressure was higher for group II at all cuff volumes. More number of patients (89%) in group II had a fiber optic score of I and II as compared to group I which had 81% patients with score I and II.ConclusionWe conclude that PLMA is easy to insert with a short insertion time, high success of placement at first attempt, and capable of achieving a more effective seal than LMA.     

A comparison of the laryngeal mask airway ProSeal and the laryngeal tube airway in paralyzed anesthetized adult patients undergoing pressure-controlled ventilation

We compared the laryngeal mask airway ProSeal (PLMA) and the laryngeal tube airway (LTA), two new extraglottic airway devices, with respect to: 1) insertion success rates and times, 2) efficacy of seal, 3) ventilatory variables during pressure-controlled ventilation, 4) tidal volume in different head/neck positions, and 5) airway interventional requirements. One-hundred-twenty paralyzed anesthetized ASA physical status I and II adult patients were randomly allocated to the PLMA or LTA for airway management. A standardized anesthesia protocol was followed by two anesthesiologists experienced with both devices. The criteria for an effective airway included a minimal expired tidal volume of 6 mL/kg during pressure-controlled ventilation at 17 cm H(2)O with no oropharyngeal leak or gastric insufflation. First attempt success rates at achieving an effective airway were similar (PLMA: 85%; LTA: 87%), but after 3 attempts, success was more frequent for the PLMA (100% versus 92%, P = 0.02). Effective airway time was similar. Oropharyngeal leak pressure was larger for PLMA at 50% maximal recommended cuff volume (29 +/- 7 versus 21 +/- 6 cm H(2)O, P < 0.0001), but was similar at the maximal recommended cuff volume (33 +/- 7 versus 31 +/- 8 cm H(2)O). Tidal volumes (614 +/- 173 versus 456 +/- 207 mL, P < 0.0001) were larger and ETCO(2) (33 +/- 9 versus 40 +/- 11 mm Hg, P = 0.0001) lower for the PLMA. The number of airway interventions was significantly less frequent for the PLMA. Airway obstruction was more common with the LTA. When comparing mean tidal volumes in different head/neck positions, the quality of airway was unchanged in 56 of 60 patients (93%) with the PLMA and 42 of 55 (76%) with the LTA (P = 0.01). The PLMA offers advantages over the LTA in most technical aspects of airway management in paralyzed patients undergoing pressure-controlled ventilation. IMPLICATIONS: The laryngeal mask airway ProSeal offers advantages over the laryngeal tube airway in most technical aspects of airway management in paralyzed patients undergoing pressure-controlled ventilation.     

The I‐gel®, a single‐use supraglottic airway device with a non‐inflatable cuff and an esophageal vent: an observational study in children

Background: The I‐gel^® is a new single‐use supraglottic airway device with a non‐inflatable cuff. It is composed of a thermoplastic elastomer and a soft gel‐like cuff that adapts to the hypopharyngeal anatomy. Like the LMA‐ProSeal, it has an airway tube and a gastric drain tube. Little is known about its efficiency in pediatric anesthesia. Methods: Fifty children above 30 kg, ASA I–II, undergoing a short‐duration surgery were included in this prospective, observational study. We evaluated ease in inserting the I‐gel^®, seal pressure, gastric leak, complications during insertion and removal, ease in inserting the gastric tube and ventilatory parameters during positive pressure ventilation. Results: All devices were inserted at the first attempt. The mean seal pressure was 25 cmH₂O. There was no gastric inflation and gastric tube insertion was achieved in all cases. The results appear similar to those in a previous study concerning laryngeal mask airway in terms of leak pressure and complication rates. Conclusion: Because the I‐gel^® has a very good insertion success rate and very few complications, it seems to be an efficient and safe device for pediatric airway management.     

Einsatz der ProSeal®-Kehlkopfmaske der Größe 3 bei Kindern

BACKGROUND: The low-pressure airway seal of the Classic laryngeal mask airway (CLMA) can be inadequate for positive pressure ventilation (PPV) in children. The ProSeal laryngeal mask airway (PLMA) forms a more effective seal of the airway than the CLMA and facilitates gastric tube placement in adults. The size 3 PLMA can be used in adults and children. METHODS: The CLMA and PLMA were studied in random order -- crossover -- in 30 anaesthetized, non-paralysed children (average age 10.6 years, average body weight 39 kg). Airway leak pressure, maximum tidal volume, ease of insertion, quality of initial airway and fiberoptic position were determined. Gastric tube placement was assessed for the PLMA. RESULTS: The mean airway leak pressure in neutral head position (27.0 vs. 16.8 cm H(2)O), maximum flexion (38.3 vs. 26.2 cm H(2)O) and maximum extension (21.1 vs. 14.2 cm H(2)O) as well as the mean maximum tidal volume (1432 vs. 1062 ml) were significantly higher (p<0.001) for the PLMA. Air insufflation into the stomach occurred with the CLMA but not with the PLMA. Gastric tube placement was possible in all patients. CONCLUSIONS: The high reliability of g-tube placement and the significantly increased airway leak pressure seem to make the size 3 PLMA a more suitable device for PPV in children than the same size CLMA.     

Klinischer Einsatz der ProSeal?-Kehlkopfmaske bei S?uglingen, Kindern und Jugendlichen

Background

In contrast to the adult population scientific data on ProSeal?-LMA (PLMA) usage in infants, children, and adolescents are rather limited. Most data have been generated by expert users in studies on small numbers of patients. The aim of this study was to gather comprehensive data about the characteristics, efficacy and safety of its routine use in children at a teaching institution.

Methods

Using a standardized reporting form the following data were collected in the course of a prospective survey on PLMA usage in patients aged up to 18 years: user characteristics, patient characteristics, type and duration of operation, details of airway management and anesthetic technique, details of PLMA usage-related critical incidents and postoperative status of the patient.

Results

Use of the PLMA was documented in 512 patients by 61 anesthesiologists (32% staff grade, 68% trainees). The average age, height and weight of the patients was 8 years (range 0?C17 years), 130?cm (range 54?C193?cm) and 29?kgBW (range 5?C130?kgBW), respectively. Anesthesia was induced intravenously in 458 patients (89.5%) and by inhalation in 54 patients. Maintenance of anesthesia was by total intravenous anesthesia (propofol) in 184 patients (36.5%) and by an inhalational agent (sevoflurane or desflurane) in 320 patients (63.7%). Neuromuscular blocking agents were used in 7 patients (1.4%). The patients were anesthetized for an average of 80?min (range 15?C270?min) and insertion success rate was 99% with a maximum of 3 attempts. The average initial airway leak pressure was 27cm?H₂O (range 12?C40?cm?H₂O); however, lower pressures were recorded for smaller size masks (size 1.5?C2.5) without a dorsal cuff than for larger size masks (size 3?C5; p<0.01). Ventilation was controlled in 96% and combined with PEEP in 39% of cases. Critical incidents associated with PLMA were documented in a total of 8.4% of cases, the majority being minor trauma, evidenced by blood on the PLMA on removal, followed by some form of airway obstruction. In 3.3% of cases these incidents were judged as clinically relevant of which 0.6% were classified as serious. Twice as many problems occurred during induction of anesthesia as in the maintenance phase and emergence phase of anesthesia (p=0.037). In 1.6% the PLMA was abandoned in favor of the endotracheal tube. In 7 patients the PLMA was exchanged in the induction room whereas in 1 patient this took place intraoperatively. Failure of ProSeal? laryngeal mask use correlated with the level of PLMA use experience with 75% of failures caused by users with an experience of less than 50 uses and no failure in users with an experience of more than 100 uses. Failure did not correlate with the size of the mask. In 2 cases the PLMA was successfully used after failed endotracheal intubation. In 6 patients drainage of regurgitated gastric fluid through the drain tube was documented. No long-term adverse sequelae resulted in any patient.

Conclusion

This survey demonstrates that the PLMA can be used effectively in infants, children and adolescents in the routine university clinical practice setting. However, this study does not confirm the extremely high success and low complication rates reported in controlled studies. The results support the assumption that with the PLMA regurgitated gastric fluid can be drained away from the larynx through the drain tube.     

Glottic insertion of the ProSealTM LMA occurs in 6% of cases: A review of 627 patients

Purpose

Glottic insertion of the ProSeal^TM Laryngeal Mask Airway (PLMA) has received little attention in the anesthesiology literature. We investigated the incidence and depth of insertion associated with this important cause for a failed insertion attempt with the PLMA.

Methods

With Institutional Review Board approval, we reviewed 15-months’ use of the PLMA. Diagnosis of glottic insertion involved a test with children’s bubble solution placed on the drain tube port, as well as a fibreoptic examination of the airway of patients experiencing airway obstruction. Patients were anesthetized and paralyzed and the PLMA was inserted deflated with the fingertip method (women size 4, men size 5). The cuff was inflated and a soap membrane established on the drain tube port. Glottic insertion was diagnosed by applying fingertip pressure to the patient’s chest wall and observing pulmonary exhalation via the drain tube and bubble formation. The PLMA was then removed and reinserted without further assessment. For all patients, we used a fibrescope to determine the cause of unexplained airway obstruction after the PLMA was considered successfully inserted.

Results

[There were 627 patients (391 women, 236 men). We diagnosed glottic insertion in 38/627 (6.1 %) patients, 37 by the soap membrane test and one with airway obstruction and direct fibreoptic visualization of malposition. Following glottic insertion, successful reinsertion of the PLMA behind the larynx was always associated with greater depth of insertion by an average 2.0 cm.

Conclusion

Glottic insertion can be easily and quickly diagnosed and our results suggest the incidence and importance of malposition are under-reported in the literature.     

The ProSeal laryngeal mask airway size selection in male and female patients in an Asian population

The aim of this study was to investigate if size 5 compared with size 4 ProSeal laryngeal mask airway (PLMA) in Asian men and size 4 compared with size 3 ProSeal laryngeal mask airway (PLMA) in Asian women, would give a better glottic seal. We conducted a randomized crossover study involving 30 male and 30 female patients of Asian origin. Size 4 and size 5 PLMA were studied in men and size 3 and size 4 PLMA were studied in women. The patients were anaesthetized and paralysed and the PLMA was inserted with the introducer. The oropharyngeal leak pressure (OLP), ease of insertion, anatomical position, mucosal injury, visibility of cuff in the mouth and volume of air required to achieve an intracuff pressure of 60 cmH2O were studied. In male patients, oropharyngeal leak pressure was higher when size 5 PLMA was used (P < 0.001) and there was a higher incidence of mucosal injury (P = 0.025). For female patients, oropharyngeal leak pressure was higher with size 4 PLMA (P = 0.036) while the number of insertion attempts, anatomical position and mucosal injury were similar. The cuff was not visible in the oral cavity in any cases. The mean volume of air required to achieve an intracuff pressure of 60 cmH2O was less than the maximum recommended by the manufacturers. The size 5 PLMA in Asian men and size 4 PLMA in Asian women resulted in a more effective glottic seal. The use of size 5 PLMA in Asian men led to increased mucosal injury.     

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.     

The Size 1 ProSeal™ laryngeal mask airway in infants: a randomized,noncrossover study with the Classic™ laryngeal mask airway

Background: In recent years, numerous scientific publications have endorsed the superiority of the ProSeal? laryngeal mask airway (PLMA) over the Classic? laryngeal mask airway (cLMA) in adults, children, and infants. The PLMA forms a better seal for both the respiratory and gastrointestinal tracts, provides easier access to the gastrointestinal tract, and exerts lower mucosal pressures for a given seal pressure. This study aims to determine whether this superiority can also be observed for the size 1 PLMA used in anesthetized neonates and infants with positive pressure ventilation. Methods: Sixty consecutive neonates and infants undergoing elective surgical procedures were randomized to airway management with the size 1 PLMA or cLMA. For all patients, we recorded ease of insertion, effective airway time, number of placement attempts, oropharyngeal leak pressure, fiberoptic position, audible leaks, mask displacement, number of reinsertions during maintenance, gastric insufflation, and frequency of blood stain. Results: Ease of insertion, successful insertion in <3 attempts, fiberoptic position of the airway tube, and frequency of blood stain were similar in both groups. Effective airway time was lower for the PLMA group (30.5 vs 35.6 s). Oropharyngeal leak pressure was higher with the PLMA (32.9 vs 22.2 cm H₂O, P < 0.001) and gastric insufflation less common (0% vs 6%, P = 0.492). There were fewer mask displacements during maintenance of anesthesia with the PLMA (0% vs 26.7%, P < 0.001). Mask reinsertion was not necessary during maintenance of anesthesia with the PLMA, although it was necessary in 14 cases in the cLMA group (0% vs 46%, P < 0.001). Audible leaks were less common with the PLMA (0% vs 46%, P < 0.001). Conclusions: We conclude that the size 1 PLMA is a stable, safe, and efficacious airway control device during neonatal and infant anesthesia, allowing higher peak airway pressure during positive pressure ventilation, with fewer mask displacements and gastric insufflations than the cLMA.