Summary

Background and objective: We compared the laryngeal mask airway (LMA™) and the laryngeal tube (LT®) with the newly introduced perilaryngeal airway (CobraPLA®, PLA) with regard to haemodynamic responses induced by airway insertion, clinical performance and occurrence of postoperative sore throat after short surgical procedures. Methods: After premedication, 90 ASA I–II patients awaiting short surgical procedures were randomized to receive, LMA, LT or PLA. Anaesthesia was induced with intravenous propofol (2.5 mg kg−1) and mivacurium (0.2 mg kg−1). Number of attempts, time of insertion of the device, any other unwanted effect, mean aterial pressure, heart rate, oxygen saturation and end-tidal carbon dioxide were recorded. At the end of surgery, the cuff of the device was immediately deflated and the airway device was removed. The device was examined and noted for the presence of visible blood. Patients were asked to rate their throat soreness, dysphonia and dysphagia 1 and 24 h postoperatively. Results: There were no differences in haemodynamic variables. Insertion times for the devices were similar (LMA: 20 ± 11 s, LT: 19 ± 14 s and PLA: 21 ± 12 s.) The success rates at first insertion were lower in the (LMA group (57%) when compared with the PLA (97%, P < 0.05). The number and type of airway interventions for achieving an effective airway were similar. When the airways were removed 50% of the PLA devices had positive blood traces, while only 17% of the LMA and LT devices had positive blood traces (P < 0.01). Fifty percent of the patients suffered from a sore throat in the PLA group, which was significantly higher than in the LMA and LT groups (P < 0.05). Conclusion: We conclude that haemodynamic, ventilation and oxygenation variables throughout the surgery were similar with, LMA, LT and PLA, but LT and PLA were easier to insert; LMA and LT caused less mucosal trauma.

Summary

Background and objective: The modified Airway Management Device (AMD) and the Proseal laryngeal mask airway (PLMA) are both supraglottic airway devices designed to maintain airway patency and allow ventilation during anaesthesia. In this prospective, randomized trial, we compared the two devices in patients undergoing major gynaecological procedures. Methods: Eighty-two patients undergoing elective gynaecological surgery were randomized to two groups. Group A (n = 41) had the AMD and Group P (n = 41) the PLMA inserted after induction of anaesthesia. We compared the success of airway placement, time to achieve an airway, oropharyngeal leak pressure and complications associated during anaesthesia. Results: There were no differences in patient characteristic profile for both groups. First time insertion success rates were significantly higher in Group P than in Group A (100% vs. 83%, P < 0.012). Time taken to achieve airway was also significantly shorter in Group P than in Group A (mean 21.9 ± 7.8 s vs. 40.2 ± 48.0 s, P < 0.001). The oropharyngeal leak pressure was significantly higher for Group P than Group A (mean 31.2 ± 5.7 cmH2O vs. 24.2 ± 8.3 cmH2O, P < 0.001). Ten patients in Group A had transient loss of airway during anaesthesia and needed manipulation of the airway device and four patients needed to have the airway switched to PLMA for the rest of the procedure. Conclusions: The modified AMD has a significant lower first time successful placement rate, required a longer insertion time and has a lower oropharyngeal leak pressure than the PLMA. It also demonstrated an increased loss of airway during anaesthesia. The modified AMD needs further evaluation on its efficacy and safety before its further use can be recommended.

Summary

Background and objective: We tested the feasibility of using the intubating laryngeal mask airway Fastrach™ (ILMA) as a ventilatory device and for flexible lightwand-guided tracheal intubation for out-of-hospital cardiopulmonary resuscitation by an emergency physician. Methods: After completion of a training programme, a single experienced emergency physician used the technique for all patients requiring out-of-hospital tracheal intubation over a 10-month period. If access to the head and neck was limited, the intubating laryngeal mask airway was inserted from below and to the side, otherwise it was inserted from above the head. Data about the time for the ambulance to reach the patient, whether or not access to the head and neck was limited, whether or not circulation was successfully restored, and the insertion and intubation success rates were noted. Results: The mean (range) time for the ambulance to reach the patient was 12 (10–20) min. Access to the head and neck was limited in 8/37 (22%). Circulation was successfully restored in 10/37 (27%). The intubating laryngeal mask airway was successfully inserted at the first attempt in 35/37 (95%) and at the second attempt in 2/37 (5%). The tracheal tube was successfully inserted in 25/37 (67.5%) at the first attempt, 7/37 (19%) at the second attempt and 5/37 (13.5%) at the third attempt. There were no overall failures for intubating laryngeal mask airway insertion or tracheal intubation. There were no differences in success rate between positions. Oesophageal intubation was detected and corrected in 2/37 (5%). Conclusion: The intubating laryngeal mask airway has a high success rate as a ventilatory device and as a flexible lightwand-guided airway intubator during out-of-hospital cardiopulmonary resuscitation by a well-trained emergency physician. This technique may be particularly useful when there is limited access to the head and neck.

Summary

Background and objective: Minimizing cervical vertebrae motion during endotracheal intubation is important in patients with cervical instability. The aim of this study was to compare upper cervical spine extension during endotracheal intubation using three different techniques.

Methods: Duration of intubation and movement of upper cervical vertebrae during endotracheal intubation were compared in 33 patients undergoing lumbar laminectomy. Patients requiring tracheal intubation under general anaesthesia and neuromuscular blockade were randomly allocated into three groups – direct laryngoscopy, intubating laryngeal mask (LM) airway and fibreoptic laryngoscopy. The procedure was recorded by video-fluoroscopy and analysed with computer-assisted measurements. The maximum movement of the C1/C2 and C2/C3 vertebrae during intubation were obtained. Data were analysed using one-way analysis of variance with Bonferroni and Kruskal–Wallis tests.

Results: We found statistically significant movement between the first and second, but not between the second and third cervical vertebrae. The mean (±SD) movement at C1/C2 was 10.2 ± 7.3° with direct laryngoscopy, 5.0 ± 6.3° with LM and 1.6 ± 3.2° with fibreoptic laryngoscopy. This difference was statistically significant (P = 0.01) between the direct and fibreoptic laryngoscopy groups. The maximum movement at C2/C3 was 2.2 ± 10.1° with direct laryngoscopy, 3.5 ± 5.1° with LM and 0.5 ± 3.2° with fibreoptic laryngoscopy. Duration of intubation was significantly longer in the intubating LM group (P < 0.001).

Conclusion: We conclude that fibreoptic laryngoscopy is the more suitable intubation technique when cervical spine movement is not desired.

We describe a new technique for removing anterior vocal fold lesions, which cannot be visualized with conventional suspension laryngoscopy. These situations are rare and the only alternative surgeons have had previously is an open laryngeal procedure. The technique we describe involves the use of a laryngeal mask airway (LMA), a flexible bronchoscope with biopsy channel, a 400 μm laser fibre and KTP/532 nm laser. This method was used to treat two patients in whom conventional suspension laryngoscopy had previously been attempted and abandoned.

Background and objective: To compare the conditions for insertion of the laryngeal mask airway using sevoflurane or propofol plus fentanyl. We evaluated the haemodynamic changes and cost of induction of anaesthesia in both groups.

Methods: Sixty patients were equally and randomly divided into two groups. Both groups received fentanyl 1 μg kg−1. Patients in the sevoflurane group were induced with 8% sevoflurane and those in the propofol group with propofol 2.5 mg kg−1. Conditions for insertion were graded on a three-point scale using six variables. Overall, conditions were assessed as excellent, satisfactory or poor based on the total score in each group. Systolic and diastolic arterial pressure and heart rate were recorded for 6 min after mask insertion. The financial cost of induction in both groups was calculated.

Results: The mean (±SD) time taken from induction to successful laryngeal mask insertion was significantly shorter with propofol (68.70 ± 22.60 s) compared with sevoflurane (149.83 ± 55.25 s). Excellent or satisfactory conditions were observed in 30 (100%) patients in the propofol group and in 29 (96.66%) in the sevoflurane group. Systolic and diastolic arterial pressures were significantly lower in the propofol group. The cost of sevoflurane used was €3.95 ± 1.48 (Rs 216.23 ± 64.66) (P < 0.05) compared with that of propofol, which was €3.23 ± 0.65 (Rs 141.00 ± 28.20).

Conclusions: Although there was a faster induction with propofol-fentanyl, conditions for insertion of the laryngeal mask airway were similar in both groups. Haemodynamic stability was better with sevoflurane-fentanyl. The propofol-fentanyl combination was more cost-effective.

The intubating laryngeal mask airway is a modification of the conventional laryngeal mask and is used as a tool for difficult intubation. It can be inserted without placing the head and neck in the Magill position and has been used successfully in cervical spine injuries. Reported is a case of successful insertion of the intubating laryngeal mask and subsequent intubation through it in a patient with ankylosing spondylitis with cervical involvement resulting in a fixed flexion deformity who underwent coronary artery bypass grafting.

Background and objective The intubating laryngeal mask is designed to act as a ventilatory device and as an aid to blind tracheal intubation in adults. The aim of this study was to evaluate the efficacy of the intubating laryngeal mask for ventilation of the lungs and tracheal intubation in children using video-endoscopic control.

Methods The handling and efficacy of the size 3 intubating laryngeal mask for tracheal intubation in 80 children weighing ≥ 25 kg were assessed under video-endoscopic control. Ease of intubating laryngeal mask insertion, adequacy of lung ventilation through the intubating laryngeal mask and airway sealing pressures were recorded. Tracheal intubation was performed blindly by the intubator, while the supervisor observed the procedure on the video display. If blind intubation failed at the first attempt, the monitor view was used to guide the tracheal tube into the trachea. The success rate and time required for successfully placing the tracheal tube were recorded.

Results Insertion of the intubating laryngeal mask was easy in all children. Lung ventilation through the intubating laryngeal mask was uniformly excellent. Blind tracheal intubation at the first attempt was successful in 53 children (66%) within 18.8 ± 4.1 s. Twenty-four of the 27 failed blind intubation attempts were successfully intubated with video-endoscopic guidance within 28.6 ± 9.4 s. Two children required replacing the intubating laryngeal mask, one child had to be intubated conventionally.

Conclusions The size 3 intubating laryngeal mask provides an airway that is easy to establish in children ≥ 25 kg with excellent ventilation conditions and allows blind tracheal intubation at the first attempt with a high success rate. Endoscopic monitoring improves its safety and intubation success rate.

Backgound and objective A postal survey was conducted in order to investigate current practice in airway management amongst Dutch anaesthetists and to investigate the role of recent training and the role of an ‘Access to the Airway’ airway management course.

Methods A questionnaire containing 27 questions was sent to all practising anaesthetists in The Netherlands. Questionnaires were returned anonymously and were analysed using the Pearson χ2-test (P < 0.05) with the SPSS® version 8.0 statistical software program.

Results The response rate was 42%. Of the respondents, 78% claim often or always to assess the expected degree of difficulty in tracheal intubation as part of routine preoperative assessment. The American Society of Anesthesiologist’s Difficult Airway Algorithm was used by 19% of respondents. A wide variety of airway management techniques is being used. In 36% of all general anaesthetics a laryngeal mask airway is used. In 1.1% of all general anaesthetics tracheal intubation is performed with the flexible fibrescope.

Conclusions Dutch anaesthetists, who commenced anaesthetic training after 1988, and those who attended the airway management course ‘Access to the Airway’ are significantly more likely to follow the American Society of Anesthesiologist’s Difficult Airway Algorithm and to use adjunctive techniques for airway management.

Background and objective The intubating laryngeal mask (intubating laryngeal mask airway) was designed to facilitate blind intubation. Its value as an adjunct to fibreoptic laryngoscopy has not been evaluated. This study compares the intubating laryngeal mask airway with the standard laryngeal mask airway as conduits for fibreoptic laryngoscopy.

Methods The fibreoptic view of the laryngeal inlet was graded via both devices in 60 anaesthetized patients. The fibreoptic view through the intubating laryngeal mask airway was assessed after the central epiglottic elevator bar had been lifted out of the field of vision by an 8-mm Euromedical® tracheal tube, which was inserted to a depth of 18 cm. The fibreoptic view from the aperture bars of the laryngeal mask was recorded.

Results The vocal cords were viewed less frequently through the intubating laryngeal mask airway (52%) than through the laryngeal mask airway (92%) [difference = 40% (95% CI = 26% to 54%), P < 0.0001].

Conclusion The view of the laryngeal inlet is better through the laryngeal mask airway than through a tracheal tube inserted to 18 cm in the intubating laryngeal mask.

Background and objective Minimal- and low-flow anaesthesia (fresh gas flow below 1 L min−1) provide many advantages, including reduced cost, conservation of body heat and airway humidity. An airtight seal is essential between the airway device and the airway of the patient. Therefore, we investigated whether the airtight seal created by a laryngeal mask airway allows controlled ventilation of the lungs when the fresh gas flow is reduced to 0.5 L min−1 and compared this with an endotracheal tube.

Methods In a prospective clinical study, 207 patients were managed using a laryngeal mask or an endotracheal tube. After intravenous induction of anaesthesia and 15 min of high fresh gas flow, the flow was reduced to 0.5 L min−1. The breathing system was monitored for airway leaks, and the patients were assessed for complications after airway removal and postoperative discomfort.

Results Both the laryngeal mask and endotracheal tube allowed fresh gas flow reduction to 0.5 L min−1 in 84.7% and 98.3% of cases respectively (small leaks: 12% laryngeal mask, 1.7% endotracheal tube). Three patients with the laryngeal mask (3.3%l) had airway leaks that were too large to permit any reduction in the fresh gas flow.

Conclusions The use of the laryngeal mask airway was more likely to be associated with a gas leak than use of an endotracheal tube; however, if modern anaesthesia machines and monitors are used, in 96.7% of the patients managed with a laryngeal mask a reduction in the fresh gas flow to 0.5 L min−1 was possible. The incidence of coughing and postoperative complaints (sore throat, swallowing problems) was higher after use of an endotracheal tube.

We determined (a) the haemodynamic responses to intubating laryngeal mask (ILM) airway insertion/intubation and removal in anaesthetized patients, and (b) whether the timing of ILM removal influences these responses. One-hundred and twenty patients without cardiovascular disease were studied. ILM airway insertion/intubation was 5 min after induction with propofol 2mg kg−1 and maintenance of anaesthesia with sevoflurane 2% in oxygen 33% and nitrous oxide. Patients were randomly assigned for removal of the intubating laryngeal mask airway at 1, 3 and 5 min after successful intubation. Systolic and diastolic arterial pressures and heart rate were recorded preinduction (baseline), before ILM airway insertion/intubation, at 1-min intervals after insertion/intubation, and at 1-min intervals for 5 min after ILM removal. ILM insertion was successful at the Arst attempt in all patients, but 46 patients required more than one intubation attempt. Compared with baseline values, there were no increases in systolic or diastolic arterial pressure, but there was an increase in heart rate 1 min after ILM insertion/intubation (9%, P < 0.001) and 1 min after ILM removal (8%, P < 0.01). There was a significant increase in systolic and diastolic pressures and heart rate 1 min after ILM insertion/intubation (30%, 31% and 15%; all: P < 0.002) compared with before ILM insertion/intubation values and 1 min after ILM removal (9%, 8% and 7%; all P < 0.05) compared with 1 min after ILM insertion/intubation values. Removal of the ILM 1 min after successful intubation resulted in higher arterial pressure compared with removal at 3 min (systolic arterial pressure 10% higher for 1 min, P=0.01) and 5 min (systolic arterial pressure 10–23% higher for 3 min, P < 0.01; diastolic arterial pressure 10–20% higher for 4 min, P > 0.02), but there were no differences in heart rate between groups. Systolic and diastolic arterial pressures were greater if more than one intubation attempt was required. Early removal or multiple intubation attempts did not exceed baseline haemodynamic values. We conclude that ILM insertion/intubation and removal in anaesthetized patients produces little or no haemodynamic response, even if multiple intubation attempts are required. The timing of removal exerts a small, but clinically unimportant influence on these responses.

Fibreoptic bronchoscopy is often used to diagnose tracheomalacia under local anaesthesia. However, in children, general anaesthesia may be required due to difficulty in obtaining co-operation. A 1-yr-old girl with a suspected congenital tracheomalacia was scheduled for diagnostic fibreoptic bronchoscopy. During induction of anaesthesia by inhalation of increasing concentration of sevoflurane, spontaneous breathing became irregular and a partial airway obstruction occurred. Because vecuronium relieved the airway obstruction, the airway was managed using a laryngeal mask. No further airway obstruction occurred during fibrescopy under controlled ventilation, but when spontaneous breathing resumed, marked airway obstruction occurred. The trachea was intubated immediately. Caution is required to manage the airway without tracheal intubation during general anaesthesia in the patient with tracheomalacia.

There is a risk of regurgitation if a laryngeal mask airway is used with intermittent positive pressure ventilation. The lower the pressure gradient between airway and stomach, the less will be the likelihood of stomach insufflation with gas and consequent regurgitation. A flow generator ventilator, such as the Penlon Nuffield 200 which achieves a peak pressure at the end of inspiration at any given tidal volume, is likely to produce a higher peak airway pressure than a pressure generator. Replacing the expiratory valve by a venturi gives a preferable flow pattern with an inspiratory pressure plateau. At equal tidal volumes, the venturi modification provided a 10% lower inflation pressure (standard deviation 6%, P < 0.01) and a 1.8% smaller leak (P < 0.05) past the laryngeal mask airway. The same comparison but using identical inflation pressures, gave 8% larger tidal volumes (standard deviation 5.1%, P < 0.01) and a 2% smaller leak (P < 0.01) past the laryngeal mask airway.