Positive pressure ventilation with the ProSeal versus classic laryngeal mask airway: a randomized, crossover study of healthy female patients

Comparison of the Laryngeal Mask Airway ProSeal and the Streamlined Liner of the Pharynx Airway During General Anesthesia: A Systematic Review and Meta-analysis

PURPOSE

The purpose of this article is to compare the safety of the laryngeal mask airway ProSeal (PLMA) and the streamlined liner of the pharynx airway (SLIPA) during general anesthesia.

DESIGN

This study is a systematic review and meta-analysis.

METHODS

Two authors performed searches of Embase, Web of Science, and PubMed to identify clinical trials that compared PLMA and SLIPA in patients receiving general anesthesia. Relative risk (RR) with corresponding 95% confidence intervals (CI) were used to pool the dichotomous data. The mean difference (MD) and the associated 95% CI were applied to pool continuous data. RevMan 5.0 software was used for data analysis.

FINDINGS

A total of 15 studies with 1263 patients were included. There was no significant difference between PLMA and SLIPA in the rate of insertion success on the first attempt (RR = 1.02, 95% CI [0.95, 1.09], P = .59), airway sealing pressure (MD = 0.75, 95% CI [-0.09, 1.58], P = .08) and the incidence of a sore throat (RR = 0.85, 95% CI [0.7, 1.04], P = .12). The insertion time of PLMA was shorter than SLIPA (MD = 5.24, 95% CI [0.51, 9.98], P = .03), and the incidence of bloodstaining on the device was lower (RR = 0.72, 95% CI [0.55, 0.94], P = .02).

CONCLUSIONS

Both devices have a high rate of insertion success on the first attempt and airway sealing pressure. But PLMA has a shorter insertion time and less incidence of blood staining, which is more advantageous than SLIPA.

Gum Elastic Bougie-guided Insertion of the ProSeal™ Laryngeal Mask Airway

We tested the hypothesis that gum elastic-bougie-guided insertion of the ProSeal™ Laryngeal Mask Airway is more frequently successful than introducer tool guided insertion after failed digital insertion. One hundred anaesthetized patients (ASA 1-2, aged 18 to 80 years) were randomized for the second insertion attempt using either the gum elastic bougie-guided or introducer tool techniques. The bougie-guided technique involved priming the drain tube with the bougie, placing the bougie in the oesophagus using laryngoscope guidance, digital insertion along the palato-pharyngeal curve, and bougie removal. The introducer tool technique involved attaching the introducer tool, single-handed rotation along the palatopharyngeal curve, and introducer tool removal. Failed insertion was classified as (i) failed passage into the pharynx, (ii) malposition, or (iii) ineffective ventilation. Any blood staining was documented. Insertion was more frequently successful (50/50 vs 15/50, P=0.0002) and faster (35±17s vs 54±45s, mean±SD, P=0.006) with the bougie-guided technique. All failed insertions with the introducer tool technique were successful with the bougie-guided technique. The aetiology of failed insertion was similar for the digital and introducer tool techniques in 94% (33/35) of patients. There was no blood staining on the bougie, laryngoscope or introducer tool at removal, but blood staining was more common on the Proseal laryngeal mask airway with the introducer tool technique (9/50 vs 2/50, P=0.03). We conclude that the gum elastic bougie-guided insertion has a higher success rate and causes less trauma than the insertion tool insertion technique after failed digital insertion of the Proseal Laryngeal Mask Airway.

ProSeal versus Classic laryngeal mask airway (LMA) for positive pressure ventilation in adults undergoing elective surgery

BACKGROUND

The development of supraglottic airway devices has revolutionized airway management during general anaesthesia. Two devices are widely used in clinical practice to facilitate positive pressure ventilation: the ProSeal laryngeal mask airway (pLMA) and the Classic laryngeal mask airway (cLMA). It is not clear whether these devices have important clinical differences in terms of efficacy or complications.

OBJECTIVES

To compare the effectiveness of the ProSeal laryngeal mask airway (pLMA) and the Classic LMA (cLMA) for positive pressure ventilation in adults undergoing elective surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 3) in the Cochrane Library; MEDLINE (Ovid SP, 1997 to April 2017); Embase (Ovid SP, 1997 to April 2017); the Institute for Scientific Information (ISI) Web of Science (1946 to April 2017); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCO host, 1982 to April 2017).We searched trial registries for ongoing studies to April 2017.We did not impose language restrictions. We restricted our search to the time from 1997 to April 2017 because pLMA was introduced into clinical practice in the year 2000.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared the effectiveness of pLMA and cLMA for positive pressure ventilation in adults undergoing elective surgery. We planned to include only data related to the first phase of cross-over RCTs.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by the Cochrane Collaboration.

MAIN RESULTS

We included eight RCTs that involved a total of 829 participants (416 and 413 participants in the pLMA and cLMA groups, respectively). We identified six cross-over studies that are awaiting classification; one is completed but has not been published, and data related to the first treatment period for the other five studies were not yet available. Seven included studies provided data related to the primary outcome, and eight studies provided data related to more than one secondary outcome.Our analysis was hampered by the fact that a large proportion of the included studies reported no events in either study arm. No studies reported significant differences between devices in relation to the primary review outcome: failure to adequately mechanically ventilate. We evaluated this outcome by assessing two variables: inadequate oxygenation (risk ratio (RR) 0.75, 95% confidence interval (CI) 0.17 to 3.31; four studies, N = 617) and inadequate ventilation (not estimable; one study, N = 80).More time was required to establish an effective airway using pLMA (mean difference (MD) 10.12 seconds, 95% CI 5.04 to 15.21; P < 0.0001; I² = 73%; two studies, N = 434). Peak airway pressure during positive pressure ventilation was lower in cLMA participants (MD 0.84, 95% CI 0.02 to 1.67; P = 0.04; I² = 0%; four studies, N = 259). Mean oropharyngeal leak (OPL) pressure was higher in pLMA participants (MD 6.93, 95% CI 4.23 to 9.62; P < 0.00001; I² = 87%; six studies, N = 709).The quality of evidence for all outcomes, as assessed by GRADE score, is low mainly owing to issues related to blinding and imprecision.Data show no important differences between devices with regard to failure to insert the device, use of an alternate device, mucosal injury, sore throat, bronchospasm, gastric insufflation, regurgitation, coughing, and excessive leak. Data were insufficient to allow estimation of differences for obstruction related to the device. None of the studies reported postoperative nausea and vomiting as an outcome.

AUTHORS' CONCLUSIONS

We are uncertain about the effects of either of the airway devices in terms of failure of oxygenation or ventilation because there were very few events. Results were uncertain in terms of differences for several complications. Low-quality evidence suggests that the ProSeal laryngeal mask airway makes a better seal and therefore may be more suitable than the Classic laryngeal mask airway for positive pressure ventilation. The Classic laryngeal mask airway may be quicker to insert, but this is unlikely to be clinically meaningful.

Optimal flexible laryngeal mask airway size in children weighing 10 to 20 kg

This prospective, randomised study was conducted to assess the effect of flexible laryngeal mask airway (FLMA) size on oropharyngeal leak pressure (OLP) in children at the recommended intracuff pressure. A total of 120 children undergoing elective ophthalmic surgery were randomly assigned to the size 2 FLMA group or size 2.5 FLMA group. The primary measurement was OLP at an intracuff pressure of 40 cmH₂O. Secondary outcomes included the incidence of OLP <10 cmH₂O, insufficient ventilation, gastric insufflation, insertion time, successful first-attempt insertion rate, fibreoptic view grade and pharyngolaryngeal adverse events. The median OLP was comparable for the size 2 and size 2.5 FLMA (18 cmH₂O versus 18 cmH₂O, P=0.38). However, the size 2 FLMA group had a higher incidence of OLP <10 cmH₂O and insufficient ventilation (13.3% versus 0, P=0.006). In subgroup analyses based on weight, the size 2.5 FLMA had a lower occurrence of OLP <10 cmH₂O and insufficient ventilation (27% versus 0, P=0.0046) in children 16-20 kg. We conclude that at a 40 cmH₂O intracuff pressure, the OLP with the size 2 and size 2.5 FLMA was similar in children weighing 10-15.9 kg. However, in children weighing 16-20 kg, size 2 devices had a higher incidence of low OLP and insufficient ventilation, so a 2.5 FLMA may be preferable in this subgroup.

A randomised controlled trial comparing ProSeal laryngeal mask airway, i-gel and Laryngeal Tube Suction-D under general anaesthesia for elective surgical patients requiring controlled ventilation

Background and Aims:

The ProSeal™ laryngeal mask airway (PLMA), i-gel™ and Laryngeal Tube Suction-D (LTS-D™) have previously been evaluated alone or in pair-wise comparisons but differing study designs make it difficult to compare the results. The aim of this study was to compare the clinical performance of these three devices in terms of efficacy and safety in patients receiving mechanical ventilation during elective surgical procedures.

Methods:

This prospective, randomised, double-blind study was conducted on 150 American Society of Anesthesiologists physical status I–II patients, randomly allocated into 3 groups, undergoing elective surgical procedures under general anaesthesia. PLMA, i-gel™ or LTS-D™ appropriate for weight or/and height was inserted. Primary outcome measured was airway sealing pressure. Insertion time, ease of insertion, number of attempts, overall success rate and the incidence of airway trauma and complications were also recorded. Intergroup differences were compared using one-way analysis of variance with post hoc correction for continuous data and Chi-square test for categorical variables.

Results:

Overall success rate was comparable between the three devices (i-gel™ 100%, LTS-D™ 94%, PLMA 96%). Airway sealing pressure was lower with i-gel™ (23.38 ± 2.06 cm H₂O) compared to LTS-D™ (26.06 ± 2.11 cm H₂O) and PLMA (28.5 ± 2.8 cm H₂O; P < 0.0005). The mean insertion time was significantly more in PLMA (38.77 ± 3.2 s) compared to i-gel™ (27.9 ± 2.53 s) and LTS-D™ (21.66 ± 2.31 s; P < 0.0005).

Conclusion:

Airway sealing pressure and insertion time were significantly higher in PLMA compared to i-gel™ and LTS-D™.

Comparison of three insertion techniques of ProSeal laryngeal mask airway: A randomized clinical trial

Background and Aims:

We aimed to compare three techniques for insertion of ProSeal laryngeal mask airway (PLMA).

Material and Methods:

Two hundred ten patients (American Society of Anaethesiologists I-II, aged 18–60 years) undergoing general anesthesia using the PLMA as an airway management device were randomly allocated to digital (D), rotational (R), or pharyngoscopic (P) techniques. In the D group (n = 70), the PLMA insertion was performed by using digital manipulation. In the R group (n = 70), the PLMA was inserted into the mouth, rotated anticlockwise through 90° and advanced into the hypopharynx. In the P group (n = 70), the PLMA was inserted after gentle pharyngoscopy using laryngoscope. Success rate at the first attempt, insertion time, airway manipulations required, and postoperative complications were noted.

Results:

Insertion at first attempt was more successful with P technique than the R and D groups (100% vs. 98.5% vs. 81.4% respectively, P < 0.01). Insertion time was shortest for the P group which was statistically significant compared to the group D (P < 0.001), but comparable with the R group. None of the patients required manipulation in the P group compared to the group R (P = 0.04) and D (P < 0.001). Blood staining (group P = 2.8% vs. group R = 2.8% vs. group D = 22%, P < 0.0001) and sore throat (group P = 0% vs. group R = 6.9% vs. group D = 16.7%, both: P < 0.005) were lower with the pharyngoscopic technique.

Conclusion:

We conclude that the pharyngoscopic technique for PLMA insertion is more successful with lower incidence of complications (mucosal bleeding and sore throat).

Comparison of the i-gel and the laryngeal mask airway proseal during general anesthesia: a systematic review and meta-analysis

Objectives

Conflicting results have been reported for the i-gel and the laryngeal mask airway proseal (LMA-P) during general anesthesia. The objective of the current investigation was to compare the efficacy and safety of the i-gel vs. the LMA-P during general anesthesia.

Methods

Two authors performed searches of MEDLINE, EMBASE, CENTRAL, and Google Scholar to identify randomized clinical trials that compared the LMA-P with the i-gel during general anesthesia. A meta -analysis was performed using both random and fixed-effect models. Publication bias was evaluated using Begg's funnel plot and Egger's linear regression test.

Results

Twelve randomized clinical trials met the eligibility criteria. There were no significant differences in insertion success rate at the first attempt (risk ratio [RR] 1.01, 95% confidence interval [CI] 0.97, 1.06), ease of insertion (RR 1.14, 95% CI 0.93, 1.39), oropharyngeal leak pressure (OLP) (MD -1.98, 95% CI -5.41, 1.45), quality of fiberoptic view (RR 1.00, 95% CI 0.91, 1.10) and success rate of gastric tube insertion (RR 1.07, 95% CI 0.98, 1.18) between the i-gel and the LMA-P, respectively. The i-gel had a shorter insertion time than the LMA-P (MD -3.99, 95% CI -7.13, -0.84) and a lower incidence of blood staining on the device (RR 0.26, 95% CI 0.14, 0.49), sore throat (RR 0.28, 95% CI 0.15, 0.50) and dysphagia (RR 0.27, 95% CI 0.10, 0.74).

Conclusions

Both devices were comparable in ease of insertion to insert and both had sufficient OLP to provide a reliable airway. Only a few minor complications were reported. The i-gel was found to have fewer complications (blood staining, sore throat, dysphagia) than the LMA-P and offers certain advantages over the LMA-P in adults under general anesthesia.

Comparison of I-gel with proseal LMA in adult patients undergoing elective surgical procedures under general anesthesia without paralysis: A prospective randomized study

Background:

We compared i-gel and ProSeal laryngeal mask airway (PLMA) regarding time taken for insertion, effective seal, fiberoptic view of larynx, ease of Ryle's tube insertion, and postoperative sore throat assessment.

Materials and Methods:

In a prospective, randomized manner, 48 adult patients of American Society of Anesthesiologists I-II of either gender between 18 and 60 years presenting for a short surgical procedure were assigned to undergo surgery under general anesthesia on spontaneous ventilation using either the i-gel or PLMA. An experienced nonblinded anesthesiologist inserted appropriate sized i-gel or PLMA in patients using standard insertion technique and assessed the intraoperative findings of the study regarding regarding time taken for respective device insertion, effective seal, fiberoptic view of larynx, ease of Ryle's tube insertion, and postoperative sore throat assessment. Postoperative assessment of sore throat was done by blinded anesthesia resident.

Results:

The time required for insertion of i-gel was lesser (21.98 ± 5.42 and 30.60 ± 8.51 s in Group I and Group P, respectively; P = 0.001). Numbers of attempts for successful insertions were comparable and in majority, device was inserted in first attempt. The mean airway leak pressures were comparable. However, there were more number of patients in Group P who had airway leak pressure >20 cm H₂O. The fiberoptic view of glottis, ease of Ryle's tube insertion, and incidence of complications were comparable.

Conclusion:

Time required for successful insertion of i-gel was less in adult patients undergoing short surgical procedure under general anesthesia on spontaneous ventilation. Patients with airway leak pressure >20 cm H₂O were more in PLMA group which indicates its better suitability for controlled ventilation.

i-gel™ in Ambulatory Surgery: A Comparison with LMA-ProSeal™ in Paralyzed Anaesthetized Patients

INTRODUCTION

Supraglottic devices have mostly eliminated the need of hemodynamically stressful routine endotracheal intubation for ambulatory surgeries. We aimed to compare hemodynamics- like blood pressure (BP) and heart rate (HR) alterations caused by stress response due to i-gel™ and LMA-ProSeal™ usage in Day care surgeries. Secondary outcomes included ease of insertion, time and number of attempts for the placement of devices.

MATERIALS AND METHODS

From April 2008 to July 2009, Sixty adult ASA I-II patients of either sex, aged 20-30, were randomly allocated into two groups (Group i-gel (n=30) receiving i-gel and Group PLMA (n=30) receiving LMA-ProSeal for airway maintenance) undergoing day care surgical procedures under general anaesthesia (GA).The ease of insertion and time taken for placement of device, postoperative complications were assessed. Haemodynamic parameters (HR, BP) were noted. It was a prospective, double blinded, and randomized controlled study. Parametric data were analyzed with the unpaired t-test and non-parametric data were analyzed with the Chi-square test. Unless otherwise stated, data are presented as mean (+ SD). p <0.05 was considered statistically significant.

RESULTS

Demographically both the groups were similar. i-gel was more easily inserted than LMA-ProSeal (90% vs. 83.33% respectively). i-gel insertion time was shorter than PLMA (14.9 vs. 20.0 sec respectively) and was statistically significant. Hemodynamics (HR, BP) were less altered in i-gel than PLMA and the results were statistically significant (p <0.05).

CONCLUSION

i-Gel; a relatively newer and cheap supraglottic device; insertion is easier and quicker as well as hemodynamically less stressful when compared with LMA-ProSeal in a day care setting.

Comparative evaluation of gum-elastic bougie and introducer tool as aids in positioning of ProSeal laryngeal mask airway in patients with simulated restricted neck mobility

Background:

The ProSeal laryngeal mask airway (PLMA) is a unique laryngeal mask with a modified cuff to improve seal and a channel to facilitate gastric tube placement. This is a better device in difficult airway situations compared to classic laryngeal mask airway. This prompted us to study the ease of insertion and positioning of PLMA in patients with simulated restricted neck mobility while using gum elastic bougie (GEB) group or introducer tool (group IT) to aid insertion.

Methods:

Sixty ASA I or II patients, aged between 18 years and 60 years, undergoing minor non-head and neck surgeries in the supine position were studied. A rigid neck collar was used to simulate restricted neck mobility in all patients. After anaesthetising the patients with a standard protocol, the PLMA was inserted using either of the technique using the tongue depressor to open the mouth. The ease of insertion, positioning, haemodynamic responses to insertion and other complications related to the procedure were noted.

Results:

Regarding demographic variables, both groups were similar. The mean time taken for insertion of PLMA in group GEB was 67.80 s as compared to 46.79 s in group IT (P<0.05). Patients of group GEB had better positioning assessed by an intubating fiberscope with less end tidal carbon-di-oxide (ETCO₂) values. Systolic and diastolic blood pressures were similar. The incidence of sore throat, dysphagia, and dysphonia were higher in IT group in the 12 h, but similar in 24 h.

Conclusion:

Guided insertion technique with GEB took a longer time, but had a better positioning and lower ETCO₂ values when compared to IT technique.

A prospective, randomized, Single-blinded, comparative study of Classic Laryngeal Mask Airway and ProSeal Laryngeal Mask Airway in pediatric patients

Context:

ProSeal Laryngeal Mask Airway (PLMA) is extensively being used in pediatric anesthesia.

Aims:

To evaluate the efficacy of PLMA as compared to Classic Laryngeal Mask Airway (CLMA) for airway maintenance in pediatric patients.

Settings and Design:

A prospective, randomized, Single-blinded study was conducted in a tertiary care teaching hospital.

Materials and Methods:

Sixty ASA I and II children were included. Patients were randomized to either size 2 PLMA or size 2 CLMA groups. Parameters noted were time for insertion, number of attempts, airway sealing pressure, blood pressures (systolic, diastolic, and mean), pulse rate, end-tidal carbon dioxide (EtCO₂), peripheral oxygen saturation (SpO₂), and postoperative change in abdominal circumference, and airway trauma.

Statistical analysis used:

Parametric data were analyzed with the unpaired t-test and non-parametric data were analyzed with the chi-square (χ²) test. Unless otherwise stated, data are presented as mean (SD). Significance was taken as P < 0.05.

Results:

There was no statistical difference between the two groups for the success rates at the first attempt of insertion, airway sealing pressure, hemodynamic responses, SpO₂, EtCO₂ and postoperative changes in abdominal circumference. Patients in the PLMA group had longer time of insertion and higher incidence of airway trauma.

Conclusions:

The PLMA and the CLMA were comparable for hemodynamic and ventilatory parameters and change in abdominal circumference; however, the time taken for insertion and airway trauma was more with PLMA.

Oral gastric tube-guided insertion of the ProSeal™ laryngeal mask is an easy and noninvasive method for less experienced users

PURPOSE

The ProSeal™ laryngeal mask airway (PLMA) can be more difficult to insert than the classic laryngeal mask, especially in patients who have a thin palate with a steep oropharyngeal curve. Here, an oral gastric (OG) tube-guided technique is considered as a method that makes it easier to successfully insert a PLMA.

METHODS

Sixty patients who were scheduled to undergo general anesthesia without neuromuscular blocking were randomly allocated into two groups: 30 patients with PLMA inserted by the standard digital technique, and 30 with the PLMA inserted by an OG tube-guided technique. Most PLMA insertions were performed by less experienced users. The success rate at the first attempt, the time taken to insert the PLMA, the difficulty of the procedure, and the incidence of oropharyngeal trauma and postoperative sore throat were compared between the two groups.

RESULTS

PLMA insertion was successfully achieved at the first attempt using the OG tube-guided technique in all 30 patients. The OG tube-guided insertion required fewer attempts (P = 0.04) and led to a less difficult insertion procedure (P = 0.02) than the standard digital insertion. Effective ventilation during anesthesia was achieved in all patients, with a lower mean cuff pressure in the OG tube-guided technique group (P = 0.02). The frequency of blood sticking to the PLMA tube (P < 0.001) and the incidence of postoperative sore throat (P = 0.003) were lower in the OG tube-guided group than the standard digital technique group.

CONCLUSIONS

OG tube-guided PLMA insertion is easier for less experienced users, trainees, and experts as well as less invasive for patients than the standard digital insertion.

The Laryngeal Mask Airway Supreme for positive pressure ventilation during laparoscopic cholecystectomy

STUDY OBJECTIVE

To evaluate the Laryngeal Mask Airway Supreme (SLMA) in patients undergoing laparoscopic cholecystectomy.

DESIGN

Prospective observational study.

SETTING

University-affiliated hospital.

PATIENTS

100 ASA physical status 1, 2, and 3 adult patients undergoing laparoscopic cholecystectomy with general anesthesia.

INTERVENTIONS

The SLMA was inserted in all study patients. Patients were placed in the reverse Trendelenburg position.

MEASUREMENTS

Ease of insertion of the device and the drain tube, oropharyngeal leak pressure, frequency of postoperative sore throat, and other adverse events were recorded. The surgeon scored stomach size on an ordinal scale of 0-10 at insertion of the laparoscope and before decompression of the pneumoperitoneum.

MAIN RESULTS

Insertion of the SLMA was successful in all patients (91 pts on the first attempt, 9 pts on the second attempt). Gastric tube insertion was successful in all patients (easy in 97 pts, difficult in 3 pts). Initial mechanical ventilation was adequate in all cases. Mean oropharyngeal leak pressure at the 60 cm H(2)O cuff pressure level was 28.8 cm H(2)O (±5.2; range 18-40 cm H(2)O). Mean airway pressure before pneumoperitoneum was 17.5 cm H(2)O (±3.3; cm; range 11-26 cm H(2)O) and 22.9 cm H(2)O (±4 cm; range 16-32 cm H(2)O) after pneumoperitoneum. Median (range) stomach size on insertion of the laparoscope and change in stomach size during surgery did not interfere with the procedure in any patient. Twelve patients (12%) complained of a mild sore throat postoperatively. No other complications were reported.

CONCLUSIONS

The SLMA is easy to insert and it is an effective ventilatory device for laparoscopic cholecystectomy.

Comparison of streamlined liner of the pharynx airway (SLIPA™) with the laryngeal mask airway Proseal™ for lower abdominal laparoscopic surgeries in paralyzed, anesthetized patients

Context:

Supraglottic airway devices have been used as an alternative to tracheal intubation during laparoscopic surgery.

Aims:

The study was designed to compare the efficacy of Streamlined Liner of the Pharynx Airway (SLIPA) for positive pressure ventilation and postoperative complications with the Laryngeal Mask Airway ProSeal (PLMA) for patients undergoing lower abdominal laparoscopies under general anesthesia with controlled ventilation.

Settings and Design:

Prospective, crossover randomized controlled trial performed on patients undergoing lower abdominal laparoscopic surgeries.

Methods:

A total of 120 patients undergoing lower abdominal laparoscopic surgeries were randomly allocated into two equal groups; PLMA and SLIPA groups. Number of intubation attempts, insertion time, ease of insertion, and fiberoptic bronchoscopic view were recorded. Lung mechanics data were collected 5 minutes after securing the airway, then after abdominal insufflation. Blood traces and regurgitation were checked for; postoperative sore throat and other complications were recorded.

Statistical Analysis:

Arithmetic mean and standard deviation values were calculated and statistical analyses were performed for each group. Independent sample t-test was used to compare continuous variables exhibiting normal distribution, and Chi-squared test for noncontinuous variables. P value <0.05 was considered significant.

Results:

Insertion time, first insertion success rate, and ease of insertion were comparable in both groups. Fiberoptic bronchoscopic view was significantly better and epiglottic downfolding was significantly lower in SLIPA group. Sealing pressure and lung mechanics were similar. Gastric distension was not observed in both groups. Postoperative sore throat was significantly higher in PACU in PLMA group. Blood traces on the device were significantly more in SLIPA group.

Conclusions:

SLIPA can be used as a useful alternative to PLMA in patients undergoing lower abdominal laparoscopic surgery with muscle relaxant and controlled ventilation.

Anesthesia in prehospital emergencies and in the emergency department

PURPOSE OF REVIEW

Recently, notable progress has been made in the field of anesthesia drugs and airway management.

RECENT FINDINGS

Anesthesia in prehospital emergencies and in the emergency department is reviewed and guidelines are discussed.

SUMMARY

Preoxygenation should be performed with high-flow oxygen delivered through a tight-fitting face mask with a reservoir. Ketamine may be the induction agent of choice in hemodynamically unstable patients. The rocuronium antagonist sugammadex may have the potential to make rocuronium a first-line neuromuscular blocking agent in emergency induction. Experienced healthcare providers may consider prehospital anesthesia induction. Moderately experienced healthcare providers should optimize oxygenation, hasten hospital transfer and only try to intubate a patient whose life is threatened. When intubation fails twice, ventilation should be performed with an alternative supraglottic airway or a bag-valve-mask device. Lesser experienced healthcare providers should completely refrain from intubation, optimize oxygenation, hasten hospital transfer and ventilate patients only in life-threatening circumstances with a supraglottic airway or a bag-valve-mask device. Senior help should be sought early. In a 'cannot ventilate-cannot intubate' situation, a supraglottic airway should be employed and, if ventilation is still unsuccessful, a surgical airway should be performed. Capnography should be used in every ventilated patient. Clinical practice is essential to retain anesthesia and airway management skills.

Comparison of the Intersurgical Solus laryngeal mask airway and the i-gel supralaryngeal device

Summary We compared the performance of the Intersurgical Solus laryngeal mask airway (LMA) with that of the i-gel in 120 patients of ASA physical status during general anaesthesia with respect to oropharyngeal leak pressure, peak airway pressure, airway manipulation, insertion time, fibreoptic view, ventilatory parameters, and peri-operative complications. After receiving a standardised induction of anaesthesia, either a Solus LMA (60 patients) or an i-gel (60 patients) was inserted. One hundred and fifteen patients completed the study. The leak pressure was significantly higher in the LMA group than the i-gel group (mean (SD) 22.7 (7.7) cmH(2)O vs 19.3 (7.1) cmH(2)O; p = 0.02). A better fibreoptic view of the larynx was obtained in patients in the LMA group (p = 0.02) compared to those in the i-gel group and less airway manipulation was required in the LMA group (p < 0.01). Both devices have good performance with very low peri-operative complications. However, the Solus LMA provides a better oropharyngeal seal, provides a better fibreoptic view, and requires less manipulation to secure the airway than the i-gel.

Anaesthesia in prehospital emergencies and in the emergency room

AIMS

To review anaesthesia in prehospital emergencies and in the emergency room, and to discuss guidelines for anaesthesia indication; pre-oxygenation; anaesthesia induction and drugs; airway management; anaesthesia maintenance and monitoring; side effects and training.

METHODS

A literature search in the PubMed database was performed and 87 articles were included in this non-systematic review.

CONCLUSIONS

For pre-oxygenation, high-flow oxygen should be delivered with a tight-fitting face-mask provided with a reservoir. In haemodynamically unstable patients, ketamine may be the induction agent of choice. The rocuronium antagonist sugammadex may have the potential to make rocuronium a first-line neuromuscular blocking agent in emergency induction. An experienced health-care provider may consider prehospital anaesthesia induction. A moderately experienced health-care provider should optimise oxygenation, fasten hospital transfer and only try to intubate a patient in extremis. If intubation fails twice, ventilation should be resumed with an alternative supra-glottic airway or a bag-valve-mask device. A lesser experienced health-care provider should completely refrain from intubation, optimise oxygenation, fasten hospital transfer and only in extremis ventilate with an alternative supra-glottic airway or a bag-valve-mask device. With an expected difficult airway, the patient should be intubated awake. With an unexpected difficult airway, bag-valve-mask ventilation should be resumed and an alternative supra-glottic airway device inserted. Senior help should be called early. In a "can-not-ventilate, can-not-intubate" situation an alternative airway should be tried and if unsuccessful because of severe upper airway pathology, a surgical airway should be performed. Ventilation should be monitored continuously with capnography. Clinical training is important to increase airway management skills.

[Evaluation of the new supraglottic airway devices Ambu AuraOnce and Intersurgical i-gel. Positioning, sealing, patient comfort and airway morbidity]

BACKGROUND

Supraglottic airway devices (SGAD) have become more important in airway management over the past years and an objective comparison of the available devices is in order.

METHODS

In a prospective study the four SGADs LMA-Classic(cLMA), LMA-ProSeal (PLMA), Ambu AuraOnce and Intersurgical i-gel were compared in groups of 40 patients in ambulatory surgery, with respect to the feasibility of positioning, leak tightness, patient comfort and airway morbidity. The seal test of the airway devices was carried out with a specially constructed pneumotachograph.

RESULTS

Adequate placement on the first attempt was achieved in 92.5% with the cLMA, 85% with the PLMA, 92.5% with the AuraOnce and 82.5% with the i-gel (p>0.05). There were no clinically relevant differences in mean insertion times: cLMA 13.8 s (+/-3.4 s), PLMA 13 s (+/-3.2 s), AuraOnce 11.2 s (+/-2.7 s; p<0.05) and 13.9 s (+/-3.6 s) with the i-gel. A tight seal at a constant oropharyngeal pressure of 15 cmH(2)O was achieved in 85% of the cases (34 cases) with the cLMA, 90% (36 cases) with the PLMA, 97.5% (39 cases) with the AuraOnce and 72.5% (29 cases) with the i-gel (p<0.05). A tight seal at a constant oropharyngeal pressure of 20 cmH(2)O was seen in 62.5% with the cLMA, 60% with the PLMA, 67.5% with the AuraOnce and in 50% with the i-gel of the cases (p>0.05). Airway morbidity was not observed in any group. Significantly more patients complained of a sore throat after using the cLMA (p<0.05).

CONCLUSION

The tested SGADs were comparable with regard to ease of insertion, insertion times and airway morbidity. Considering leak tightness and patient comfort the PLMA and the AuraOnce fared better with regard to tightness of seal and patient comfort.

Comparison of the Single-use LMA Supreme with the Reusable ProSeal LMA for Anaesthesia in Gynaecological Laparoscopic Surgery

The Laryngeal Mask Airway Supreme (LMAS) is a new, single-use laryngeal mask airway with gastric access. We conducted a randomised controlled study comparing the LMAS with the reusable ProSeal Laryngeal Mask Airway (PLMA) in 70 patients undergoing general anaesthesia with paralysis for gynaecological laparoscopic surgery. Our primary outcome measure was the oropharynegal leak pressure. We also compared the two devices for ease of insertion, adequacy of ventilation and incidence of complications. Both devices had similar rates of successful insertion at the first attempt (LMAS 94% vs PLMA 91%). There was no difference in the time to establish an effective airway (LMAS 25±22 vs PLMA 24±9 seconds), although gastric tube insertion was faster for the LMAS (5±1 vs 7±3 seconds, P <0.001). The mean oropharyngeal leak pressure in the LMAS was significantly lower than in the PLMA (27.9±4.7 vs 31.7±6.3 cmH2O, P=0.007). This was consistent with a lower maximum tidal volume achieved with the LMAS (481±76 vs 515±63 ml, P=0.044). We found that after 60 minutes the cuff pressure was significantly higher in the PLMA (110±21 vs 57±8 cmH2O, P <0.001). There was no difference in the ability to provide adequate ventilation and oxygenation during anaesthesia. Complication rates were similar. We conclude that the oropharyngeal leak pressure and the maximum achievable tidal volume are lower with the LMAS than with the PLMA.

Gum elastic bougie-guided insertion of the ProSeal laryngeal mask airway is superior to the digital and introducer tool techniques in patients with simulated difficult laryngoscopy using a rigid neck collar

BACKGROUND

We compared three techniques for insertion of the laryngeal mask airway ProSeal (PLMA) in patients with simulated difficult laryngoscopy using a rigid neck collar.

METHODS

Ninety-nine anesthetized healthy female patients aged 19-68 yr were randomly allocated for PLMA insertion using the digital, introducer tool (IT) or guided techniques. Difficult laryngoscopy was simulated using a rigid neck collar. The laryngoscopic view was graded before PLMA insertion. The digital and IT techniques were performed according to the manufacturer's instructions. The guided technique involved priming the drain tube with an Eschmann tracheal tube introducer, placing the introducer in the esophagus under direct vision and railroading the PLMA into position. Failed insertion was defined by any of the following criteria: 1) failed pharyngeal placement, 2) malposition, and 3) ineffective ventilation.

RESULTS

The median laryngoscopic view was 3 and the mean interincisor distance was 3.3 cm. Insertion was more frequently successful with the guided technique at the first attempt (guided 100%, digital 64%, IT 61%; P<0.0001), but success after three attempts was similar (guided 100%, digital 94%, IT 91%). The time taken for successful placement was similar among groups at the first attempt, but was shorter for the guided technique after three attempts (guided 31+/-8 s, digital 49+/-28 s, IT 54+/-37 s; P<0.02).

CONCLUSION

The guided insertion technique is more frequently successful than the digital or IT techniques in patients with simulated difficult laryngoscopy using a rigid neck collar.

A cohort evaluation of the pediatric ProSeal laryngeal mask airway in 100 children

BACKGROUND

The ProSeal laryngeal mask airway (PLMA) has been available in pediatric sizes in the UK since 2007. Although several non-UK studies have evaluated PLMAs in children, there are little published data regarding their use in this country. Having decided to introduce the pediatric PLMA into our practice, we chose to prospectively audit the first 100 uses as part of our clinical governance.

METHODS

We studied children undergoing elective surgery who were considered suitable for a supraglottic airway. We recorded patient, surgical and insertion details, device performance data and complications. Patient management was not altered by inclusion in this audit.

RESULTS

Twenty size 1.5, 55 size 2.0, 15 size 2.5 and 10 size 3.0 PLMAs were inserted in 100 consecutive children [median age 2 years (range 2 months to 10 years) and median weight 15 kg (range 4.9-60 kg)]. The overall first attempt success rate was 93% (size 1.5, 100%; size 2.0, 100%; size 2.5, 87%; size 3.0, 90%) and overall successful insertion rate was 99%. Median leak pressure was 25 cmH(2)O. Outright failure was seen in one patient; complications were seen in another six patients (partial airway obstruction in five patients and mild laryngospasm in one patient), all of whom were transient and none of whom required intubation. No episodes of regurgitation were recorded.

CONCLUSIONS

Even without prior experience and using nonconventional insertion, pediatric PLMAs (including size 1.5) can be easily inserted and provide an effective airway.

Cricoid pressure impedes insertion of, and ventilation through, the ProSeal laryngeal mask airway in anesthetized, paralyzed patients

BACKGROUND

We designed this prospective self-controlled study to assess whether cricoid pressure hampers placement of and ventilation through the ProSeal laryngeal mask airway (ProSeal LMA) in anesthetized, paralyzed adult patients.

METHODS

After induction of anesthesia, the ProSeal LMA was inserted using the introducer tool with cricoid pressure advanced as far as possible, and the cuff pressure was set at 60 cm H2O. Ventilation adequacy and anatomic position were scored using measures previously described for ProSeal LMA assessment. Airway seal pressure was recorded. Cricoid pressure was then released, the ProSeal LMA further advanced and reseated, and the assessment repeated.

RESULTS

Lung ventilation scores, anatomic position scores, and airway seal pressure were significantly better after release of cricoid pressure and reseating of the ProSeal LMA than in the first position, where the ProSeal LMA was seated with cricoid pressure (P < 0.05). Expiratory tidal volume during intermittent positive pressure ventilation was similar with and without cricoid pressure, but peak inspiratory pressure decreased from 28 cm H(2)O with cricoid pressure to 14 cm H(2)O without cricoid pressure (P < 0.05).

CONCLUSIONS

Cricoid pressure applied before insertion hampered proper placement of the ProSeal LMA. Temporary cricoid pressure release during insertion allowed the device to be advanced to the proper position. After correct placement of the ProSeal LMA, application of cricoid pressure did not change tidal volume, but produced a significant increase in peak inspiratory pressure.

Suction catheter guided insertion of the ProSeal™ laryngeal mask airway is superior to the digital technique

PURPOSE

We tested the hypothesis that digital insertion of the ProSeal laryngeal mask airway (ProSeal LMA) is more successful when using a suction catheter (SC) as a guide.

METHODS

Two hundred and forty-three patients (ASA physical status I-III; aged 18-84 yr) were randomly allocated for the digital or SC-guided technique. The digital technique was performed according to the manufacturer's instructions. The SC technique involved priming the drain tube with the SC so that it protruded by 15 cm, blindly inserting the SC into the pharynx to a depth of 15 cm, followed by the digital technique. Failed insertion was defined by any of the following criteria: 1) failed passage into the pharynx; 2) malposition; and 3) ineffective ventilation. Any airway trauma, and visible or occult blood was noted. Sore throat, dysphonia and dysphagia were assessed 16 to 24 hr postoperatively.

RESULTS

Fewer insertion attempts were required with the SC-guided technique (P = 0.02), but first attempt and overall success were similar. The time taken to provide an effective airway was shorter for the SC-guided technique (36 +/- 24 sec vs 44 +/- 28 sec, P = 0.02). A lateral approach was required less frequently with the SC-guided technique (0% vs 4%, P = 0.0004). There were no adverse events. Mouth trauma was more frequent with the digital technique (P = 0.04), but overall trauma was similar. There were no differences in the frequency of visible or occult blood. There were no differences in postoperative airway morbidity.

CONCLUSIONS

The SC-guided technique is more frequently successful than the digital technique and is associated with less mouth trauma during insertion of the ProSeal LMA. We suggest that the SC technique may be a useful alternative when the digital technique fails.

Airway rescue in acute upper airway obstruction using a ProSeal?Laryngeal mask airway and an Aintree Catheter?: a review of the ProSeal?Laryngeal mask airway in the management of the difficult airway

We report the successful use of a ProSeal Laryngeal mask airway (PLMA) to rescue the airway when emergency tracheal intubation and ventilation of the lungs were impossible after haemorrhage into the neck following carotid endarterectomy, despite evacuation of the clot. The airway was re-established after placement of a PLMA. Fibreoptic examination of the airway revealed severe supraglottic swelling compromising airway patency. An Aintree catheter was placed in the trachea under fibreoptic guidance and a tracheal tube railroaded over this. The use of the PLMA in seven cases of difficult airway management and 11 cases of airway rescue is reviewed. Use of the PLMA was associated with high levels of success, often rescuing the airway when other techniques had failed. No complications of use of the PLMA were reported in these cases. The PLMA appears to be a useful device to assist in management of the difficult airway and for airway rescue. Potential advantages over the classic laryngeal mask airway include improved airway seal and reduced risk of aspiration. The gum elastic bougie-guided insertion technique is recommended when the PLMA is used for airway rescue.

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.

Predicted values of propofol EC50 and sevoflurane concentration for insertion of laryngeal mask Classic and ProSeal

BACKGROUND

A new laryngeal mask airway, the ProSeal (PLMA), is said to be more difficult to insert than the laryngeal mask airway Classic (CLMA) using propofol anaesthesia. Therefore, we expected a greater dose of propofol and sevoflurane to be required to insert the PLMA compared with the CLMA. We determined the effective concentration 50% (EC(50)) of propofol and end-tidal sevoflurane to allow insertion of the PLMA and the CLMA.

METHODS

Seventy-six elective female patients (aged 20-60 yr and ASA I-II) were randomly assigned to one of four groups. Either a PLMA or a CLMA was inserted using either propofol target controlled infusion or sevoflurane. Both propofol and sevoflurane targets were determined with a modified Dixon's up-and-down method. After equilibration between the predetermined blood and effect site concentrations, which had been held steady for more than 10 min, LMA insertion was attempted without neuromuscular block.

RESULTS

The predicted EC(50CLMA) and EC(50PLMA) for propofol were 3.14 (0.33) and 4.32 (0.67) micro g ml(-1). E'(CLMA) and E'(PLMA) of sevoflurane (mean (SD)) were 2.36 (0.22) and 2.82 (0.45)% (P<0.01 and 0.05, respectively).

CONCLUSIONS

The estimated concentration of propofol and the sevoflurane concentration needed to allow insertion of the ProSeal are respectively 38 and 20% greater than those needed for insertion of the Classic LMA.

[Airway equipment and its maintenance for a non difficult adult airway management (endotracheal intubation and its alternative: face mask, laryngeal mask airway, laryngeal tube)]

The airway equipment for a non difficult adult airway management are described: endotracheal tubes with a specific discussion on how to inflate the balloon, laryngoscopes and blades, stylets and intubation guides, oral airways, face masks, laryngeal mask airways and laryngeal tubes. Cleaning and disinfections with the maintenance are also discussed for each type of airway management.

Sex-based ProSeal laryngeal mask airway size selection: a randomized crossover study of anesthetized, paralyzed male and female adult patients

We compared the Size 4 and 5 ProSeal laryngeal mask airway (PLMA) in men and the Size 3 and 4, and 4 and 5 PLMA in women in terms of 1) ease of insertion, 2) oropharyngeal leak pressure (OLP), 3) ease of ventilation at a tidal volume of 10 mL/kg, 4) gas exchange, 5) location of gas leak, 6) anatomic position of the airway and drain tube, and 7) mucosal injury. Thirty male and 60 female (ASA physical status I-II; 18-80 yr old) anesthetized, paralyzed patients were studied in a crossover fashion in three equal-sized groups. PLMA insertion was performed by a single experienced operator by using digital manipulation. In male patients comparing the Size 4 and 5, OLP was higher (P = 0.0002) and leak fraction lower (P = 0.03) for the Size 5, but the number of insertion attempts, insertion time, mucosal injury, anatomic position, gas exchange, and location of gas leak were similar. In female patients comparing the Size 4 and 5 PLMA, OLP was higher for the Size 5 (P < 0.0001), but the number of insertion attempts was fewer (P = 0.02), insertion time was quicker (P = 0.02), and there was less mucosal injury (P = 0.01) with the Size 4. There were no differences in anatomic position, gas exchange, or location of gas leak. In female patients comparing the Size 3 and 4 PLMA, OLP was higher (P = 0.0005) and leak fraction was lower (P = 0.03) for the Size 4, but the number of insertion attempts, insertion time, mucosal injury, anatomic position, gas exchange, and location of gas leak were similar. There were no episodes of failed oxygenation, failed ventilation, or gastric insufflation. We conclude that if size is selected by sex, the Size 4 PLMA is preferable for women and the Size 5 PLMA for men.

IMPLICATIONS

When sex is used to select the appropriate size of the ProSeal laryngeal mask airway, the Size 4 ProSeal is preferable for women and the Size 5 ProSeal for men.

A comparison of the ProSeal and classic laryngeal mask airways for airway management by inexperienced personnel after manikin-only training

We compared the ProSeal (PLMA) and Classic (LMA) laryngeal mask airway for airway management by inexperienced personnel. Nine nurses from the post-anaesthesia care unit, with no prior experience of LMA or PLMA insertion, were observed inserting the LMA and PLMA in 60 ASA 1 to 2 anaesthetized, paralyzed adults following manikin-only training. The time to achieve an effective airway (2 consecutive expired tidal volumes (6 ml/kg; maximum 2 minutes allowed), the number of insertion attempts and the reasons for failure (inability to insert into pharynx or inadequate ventilation) were determined by analysis of digital video recordings. The first attempt success rate (LMA, 85%; PLMA, 83%), overall success rate (LMA, 88%; PLMA, 90%) and effective airway time (LMA, 39 +/- 13 s; PLMA, 43 +/- 19 s) were similar. Failure was from an inability to insert into the pharynx in five with the LMA and three with the PLMA, and inadequate ventilation with two from the LMA and three from the PLMA. Effective airway time and the number of failures were similar for the first and second device. Failure of both devices occurred in four patients. We conclude that airway management in anaesthetized, paralyzed adults is equally successful for the LMA and PLMA by inexperienced personnel following manikin-only training. The PLMA is worthy of consideration as a tool for emergency airway management by inexperienced personnel.

The PAxpress is an effective ventilatory device but has an 18% failure rate for flexible lightwand-guided tracheal intubation in anesthetized paralyzed patients

PURPOSE

The PAxpress is a new, single-use, extraglottic airway device. We evaluate: 1) insertion success rates; 2) airway sealing pressure, ventilatory capability and calculated mucosal pressures (in vitro minus in vivo intracuff pressure) at 30-60 mL cuff inflation volume; 3) the feasibility of lightwand-guided tracheal intubation; and 4) the incidence of mucosal trauma.

METHODS

Ninety anesthetized, paralyzed adults were studied. Airway management was by senior anesthesiologists with no prior experience with the PAX, but considerable experience with extraglottic airway devices and the flexible-lightwand.

RESULTS

Insertion was successful at the first attempt in 95.5% (86/90) and at the second attempt in 4.5% (4/90). Mean +/- SD airway sealing pressure at 30, 40, 50 and 60 mL cuff inflation volume was 27 +/- 8, 29 +/- 9, 32 +/- 9 and 35 +/- 7 cm H(2)O respectively; expired tidal volume at airway sealing pressure was 16 +/- 6, 18 +/- 6, 19 +/- 5 and 19 +/- 6 mL.kg(-1); and calculated mucosal pressure was 38 +/- 14, 55 +/- 20, 56 +/- 19 and 57 +/- 20 cm H(2)O. Airway sealing pressure, expired tidal volume at airway sealing pressure and calculated mucosal pressures increased with cuff inflation volume (all: P < or = 0.0002). Esophageal leak was detected in 9% (8/90), but only at peak pressures > or = 35 cm H(2)O and cuff inflation volumes > or = 40 mL. Lightwand-guided intubation was successful in 82% (74/90) of patients. Mild, moderate and severe blood staining was detected in 40% (36/90), 15% (13/90) and 1% (1/90) respectively. Blood staining was more frequent after adjusting maneuvers (22/54 vs 32/36, P = 0.002).

CONCLUSION

The PAX has a high insertion success rate and is an effective ventilatory device with a low risk of gastric insufflation, but has a moderately high failure rate for lightwand-guided intubation and is associated with a relatively high incidence of mucosal trauma. Mucosal pressures may exceed pharyngeal perfusion pressure.

The ProSeal laryngeal mask airway

The ProSeal LMA is a major advance over the Classic LMA because of the following reasons: it allows ventilation at much higher airway pressures; it protects the lungs from aspiration and the stomach from gastric insufflation; it facilitates passage of a gastric tube and monitoring devices into the esophagus; it can be inserted like the Classic or Intubating LMA; it has its own built-in bite block; malposition is detected more readily; and, through use of techniques such as gum elastic bougie-guided insertion, correct positioning is almost guaranteed. The ProSeal can be considered a replacement device for the Classic LMA, but the Flexible LMA is still preferable for most intraoral procedures, and the Intubating LMA is still preferable whenever intubation is required. Limitations are that it is slightly more difficult to insert and requires more careful thought to use optimally.

Gum-elastic bougie-guided insertion of the ProSeal laryngeal mask airway: a new technique

We determined the success rates, cardiovascular responses and airway morbidity for gum-elastic bougie-guided insertion of the ProSeal laryngeal mask airway. One hundred anaesthetized, non-paralyzed adults (ASA 1-2 aged 18 to 80 years) were studied. The ProSeal LMA drainage tube was primed with a well-lubricated 16 French gauge gum-elastic bougie with the curved end proximal and the straight end protruding 30 cm beyond the drainage tube tip. The straight end of the gum-elastic bougie was inserted into the oesophagus under laryngoscopic guidance, the laryngoscope removed and the ProSeal LMA inserted using the standard insertion technique and the gum-elastic bougie as a guide. The following variables were recorded: ease of insertion, oropharyngeal leak pressure, ventilatory capability, ease of gastric tube insertion, blood staining on the bougie or LMA at removal, and postoperative airway morbidity. Haemodynamic data were recorded immediately pre-insertion and every minute for five minutes after insertion. Gum-elastic bougie and ProSeal LMA insertion was successful at the first attempt in all patients within 50 seconds. There were no significant increases in heart rate or blood pressure. Oropharyngeal leak pressure was 33 (17-40) cmH2O and ventilation was possible without leak in all patients at 9.5 ml x kg(-1) tidal volume. There were no drainage tube or gastric air leaks. Gastric tube insertion was successful at the first attempt in all patients. Blood staining at removal was not detected on the gum-elastic bougie, but was detected in 3% of ProSeal LMAs. The incidence of sore throat, dysphagia and dysarthria was 21%, 9% and 1% respectively. We conclude that gum-elastic bougie-guided insertion of the ProSeal LMA has a high success rate and is associated with minimal haemodynamic change and a low incidence of trauma.

The ProSeal laryngeal mask in myasthenia gravis

This case describes the anaesthesia management of a patient with myasthenia gravis who required mastectomy with axillary lymph node clearance. After withholding medical therapy for the myasthenia preoperatively on the day of surgery, anaesthesia was maintained with halothane, nitrous oxide and a remifentanil infusion. Muscle relaxants were avoided, facilitated by the use of a ProSeal (Intravent, Orthofix, Maidenhead, United Kingdom) laryngeal mask airway for positive pressure ventilation. The ProSeal laryngeal mask airway is a new laryngeal mask device with a modified cuff and a drainage tube which has been shown to have advantages over older designs for use during positive pressure ventilation. The rationale for the management of this patient with myasthenia is discussed.

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.

Airway management outside the operating room

The choice of airway device for resuscitation depends on the skill of the user, the equipment available, the conscious state of the patient, the location of the patient and the probable cause of the cardiorespiratory arrest. Extraglottic airway devices are recommended by the European and American Resuscitation Councils for use when intubation skills are lacking. In this review, we discuss recent research relevant to the use of extraglottic airway devices in resuscitation.

The Laryngeal Mask Airway ProSeal(TM) as a temporary ventilatory device in grossly and morbidly obese patients before laryngoscope-guided tracheal intubation

We determined the efficacy of the laryngeal mask airway ProSeal(TM) (PLMA) as a temporary ventilatory device in morbidly obese patients before laryngoscope-guided tracheal intubation. Sixty patients (body mass index 35--60 kg/m(2)) scheduled for elective surgery, who preferred airway management under general anesthesia, were studied. The induction of anesthesia was with midazolam/fentanyl/propofol and maintenance was with sevoflurane 1%--3% in oxygen 100%. The PLMA was inserted and an effective airway established. Rocuronium was given IV for paralysis. Oropharyngeal leak pressure, ease of gastric tube placement, residual gastric volume, fiberoptic position of the airway/drainage tube, and ease of ventilation at a tidal volume of 8 mL/kg was determined. The PLMA was then removed and laryngoscope-guided tracheal intubation attempted. The number of insertion/intubation attempts (maximum two each) and time taken to establish an effective airway with each device were recorded. An effective airway was obtained at the first insertion attempt in 90% of patients (54/60) and at the second attempt in 10% (6/60). The time taken to provide an effective airway was 15 plus minus 7 s (7--42 s). Oropharyngeal leak pressure was 32 plus minus 8 cm H(2)O (12--40 cm H(2)O). The residual gastric volume was 36 plus minus 46 mL (0--240 mL). Positive pressure ventilation without air leaks was possible in 95% of patients (57/60). The vocal cords were seen from the airway tube in 75% of patients (45/60), but the esophagus was not seen. The fiberoptic view from the drainage tube revealed mucosa in 93% of patients (56/60) and an open upper esophageal sphincter in 7% (4/60). Tracheal intubation was successful at the first attempt in 90% of patients (54/60), at the second attempt in 7% (4/60), and failed in 3% (2/60). In these latter two patients, the PLMA was reinserted and surgery performed uneventfully with the PLMA. The time taken to tracheally intubate the patient was 13 plus minus 10 s (8--51 s). There were no episodes of hypoxia (SpO(2) <90%) or other adverse events. There were no differences in insertion success rate, or the time to successful insertion between the PLMA and laryngoscope-guided intubation. We conclude that the PLMA is an effective temporary ventilatory device in grossly or morbidly obese patients before laryngoscope-guided tracheal intubation.

IMPLICATIONS

The laryngeal mask airway ProSeal(TM) is an effective temporary ventilatory device in grossly and morbidly obese patients before laryngoscope-guided tracheal intubation.

Mechanical closure of the vocal cords with the laryngeal mask airway ProSeal

We report a case of mechanical closure of the vocal cords with the laryngeal mask airway ProSeal (PLMA) in an anaesthetized, paralysed 59-yr-old, 88 kg female undergoing lower-limb vascular surgery. Near-complete airway obstruction developed after a size-5 PLMA was inserted and the cuff inflated with 20 ml of air. Fibreoptic inspection revealed that the PLMA was correctly positioned, but the vocal cords were closed. Withdrawal of air from the cuff and/or moving the head and neck into the sniffing position resolved this problem.