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

2021 Update on airway management from the Anaesthesia Continuing Education Airway Management Special Interest Group

Airway Management is the key for anaesthetists dealing with patients undergoing diagnostic procedures and surgical interventions. The present coronavirus pandemic underpins even more how important safe airway management is. It also highlights the need to apply stringent precautions to avoid infection and ongoing transmission to patients, anaesthetists and other healthcare workers (HCWs). In light of this extraordinary global situation the aim of this article is to update the reader on the varied aspects of the ever-changing tasks anaesthetists are involved in and highlight the equipment, devices and techniques that have evolved in response to changing technology and unique patient and surgical requirements.

Blind intubation through Laryngeal Mask Airway in a cannot intubate-difficult to ventilate patient with massive hematemesis

Massive hematemesis could be challenging situation requiring emergency airway control and urgent surgical treatment. We report a case of difficult airway management with blind intubation through Laryngeal Mask Airway in a 56-year-old patient with massive hematemesis. After failed endoscopic attempts to stop bleeding, worsening of hemodynamics called for emergency intubation and surgery. After failed intubation attempts and face-mask ventilation worsening, a classic LMA was used for rescue ventilation and decision was made to intubate through LMA. The airway exchange was aided by a nasogastric tube (NGT) through LMA, confirmed with capnography and surgery was started successfully and uneventfully. Unexpected difficult airway can be extremely challenging situation, especially in emergency settings with no possibility to delay surgery. In those cases, literature suggests different intubating techniques through LMA. Blind intubation through LMA aided by NGT showed to be a suitable option in resources-limited settings, where advanced supraglottic devices and/or optical devices are not available.

Rescue supraglottic airway devices at caesarean delivery: What are the options to consider?

Tracheal intubation is considered the gold standard means of securing the airway in obstetric general anaesthesia because of the increased risk of aspiration. Obstetric failed intubation is relatively rare. Difficult airway guidelines recommend the use of a supraglottic airway device to maintain the airway and to allow rescue ventilation. Failed intubation is associated with a further increased risk of aspiration, therefore there is an argument for performing supraglottic airway-guided flexible bronchoscopic intubation (SAGFBI). The technique of SAGFBI has a high success rate in the non-obstetric population, it protects the airway and it minimises task fixation on repeated attempts at laryngoscopic tracheal intubation. However, after failed intubation via laryngoscopy, there is a lack of specific recommendations or indications for SAGFBI in current obstetric difficult airway guidelines in relation to achieving tracheal intubation. Our narrative review explores the issues pertaining to airway management in these cases: the use of supraglottic airway devices and the techniques of, and technical issues related to, SAGFBI. We also discuss the factors involved in the decision-making process as to whether to proceed with surgery with the airway maintained only with a supraglottic airway device, or to proceed only after SAGFBI.

Direct and indirect low skill fibre-optic intubation: A randomised crossover manikin study of six supraglottic airway devices

Background and Aims:

Fibre-optic intubation (FOI) through supraglottic airway devices (SADs) is useful in the management of the difficult airway. We compared two methods of FOI through seven SADs in a randomised crossover manikin study to assess each device's performance and discuss implications on SAD selection.

Methods:

Thirty anaesthetsiologists, 15 seniors and 15 juniors, each performed low skill FOI (LSFOI) with seven SADs using both 'direct' and 'indirect' methods. The order of method and device used were randomised. The primary end point was success rate of intubation; secondary end points were time taken for intubation, incidence of difficulties with direct and indirect LSFOI and operator device preference. Statistical analysis was with univariable analysis and comparison of proportions.

Results:

Data from six devices were analysed due to a protocol breach with one SAD. There was no difference in intubation success rate across all SADs and intubation methods. Intubation time was significantly shorter in AmbuAuragain than other SADs and shorter with the direct method of LSFOI than the indirect method (mean difference of 6.9 s, P = 0.027). Ambu Auragain had the least SAD and bronchoscope-related difficulties. Seniors had significantly shorter mean intubation times than juniors by 11.6 s (P = 0.0392). The most preferred SAD for both methods was AmbuAuragain.

Conclusion:

Low skill FOI consistently achieves a high intubation success rate regardless of experience, choice of method, or SAD used. SAD design features may significantly affect the performance of low skill FOI.

Guidelines for the management of tracheal intubation in critically ill adults

These guidelines describe a comprehensive strategy to optimize oxygenation, airway management, and tracheal intubation in critically ill patients, in all hospital locations. They are a direct response to the 4^th National Audit Project of the Royal College of Anaesthetists and Difficult Airway Society, which highlighted deficient management of these extremely vulnerable patients leading to major complications and avoidable deaths. They are founded on robust evidence where available, supplemented by expert consensus opinion where it is not. These guidelines recognize that improved outcomes of emergency airway management require closer attention to human factors, rather than simply introduction of new devices or improved technical proficiency. They stress the role of the airway team, a shared mental model, planning, and communication throughout airway management. The primacy of oxygenation including pre- and peroxygenation is emphasized. A modified rapid sequence approach is recommended. Optimal management is presented in an algorithm that combines Plans B and C, incorporating elements of the Vortex approach. To avoid delays and task fixation, the importance of limiting procedural attempts, promptly recognizing failure, and transitioning to the next algorithm step are emphasized. The guidelines recommend early use of a videolaryngoscope, with a screen visible to all, and second generation supraglottic airways for airway rescue. Recommendations for emergency front of neck airway are for a scalpel-bougie-tube technique while acknowledging the value of other techniques performed by trained experts. As most critical care airway catastrophes occur after intubation, from dislodged or blocked tubes, essential methods to avoid these complications are also emphasized.

Review of difficult airway management in thoracic surgery

The management of difficult airway (DA) in thoracic surgery is more difficult due to the need for lung separation or isolation and frequent presence of associated upper and lower airway problems. We performed an article review analysing 818 papers published with clinical evidence indexed in Pubmed that allowed us to develop an algorithm. The best airway management in predicted DA is tracheal intubation and independent bronchial blockers guided by fibroscopy maintaining spontaneous ventilation. For unpredicted DA, the use of videolaryngoscopes is recommended initially, and adequate neuromuscular relaxation (rocuronium/sugammadex), among other maneuvers. In both cases, double lumen tubes should be reserved for when lung separation is absolutely indicated. Finally, extubation should be a time of maximum care and be performed according to the safety measures of the Difficult Arway Society.

Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults

These guidelines provide a strategy to manage unanticipated difficulty with tracheal intubation. They are founded on published evidence. Where evidence is lacking, they have been directed by feedback from members of the Difficult Airway Society and based on expert opinion. These guidelines have been informed by advances in the understanding of crisis management; they emphasize the recognition and declaration of difficulty during airway management. A simplified, single algorithm now covers unanticipated difficulties in both routine intubation and rapid sequence induction. Planning for failed intubation should form part of the pre-induction briefing, particularly for urgent surgery. Emphasis is placed on assessment, preparation, positioning, preoxygenation, maintenance of oxygenation, and minimizing trauma from airway interventions. It is recommended that the number of airway interventions are limited, and blind techniques using a bougie or through supraglottic airway devices have been superseded by video- or fibre-optically guided intubation. If tracheal intubation fails, supraglottic airway devices are recommended to provide a route for oxygenation while reviewing how to proceed. Second-generation devices have advantages and are recommended. When both tracheal intubation and supraglottic airway device insertion have failed, waking the patient is the default option. If at this stage, face-mask oxygenation is impossible in the presence of muscle relaxation, cricothyroidotomy should follow immediately. Scalpel cricothyroidotomy is recommended as the preferred rescue technique and should be practised by all anaesthetists. The plans outlined are designed to be simple and easy to follow. They should be regularly rehearsed and made familiar to the whole theatre team.

Supraglottic airway devices versus tracheal intubation for airway management during general anaesthesia in obese patients

BACKGROUND

The number of obese patients requiring general anaesthesia is likely to increase in coming years, and obese patients pose considerable challenges to the anaesthetic team. Tracheal intubation may be more difficult and risk of aspiration of gastric contents into the lungs is increased in obese patients. Supraglottic airway devices (SADs) offer an alternative airway to traditional tracheal intubation with potential benefits, including ease of fit and less airway disturbance. Although SADs are now widely used, clinical concerns remain that their use for airway management in obese patients may increase the risk of serious complications.

OBJECTIVES

We wished to examine whether supraglottic airway devices can be used as a safe and effective alternative to tracheal intubation in securing the airway during general anaesthesia in obese patients (with a body mass index (BMI) > 30 kg/m(2)).

SEARCH METHODS

We searched for eligible trials in the following databases: Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 8, 2012), MEDLINE via Ovid (from 1985 to 9 September 2012) and EMBASE via Ovid (from 1985 to 9 September 2012). The Cochrane highly sensitive filter for randomized controlled trials was applied in MEDLINE and EMBASE. We also searched trial registers such as www.clinicaltrials.gov and the Current Controlled Clinical Trials Website (http://www.controlled-trials.com/) for ongoing trials. The start date of these searches was limited to 1985, shortly before the first SAD was introduced, in 1988. We undertook forward and backward citation tracing for key review articles and eligible articles identified through the electronic resources.

SELECTION CRITERIA

We considered all randomized controlled trials of participants aged 16 years and older with a BMI > 30 kg/m(2) undergoing general anaesthesia. We compared the use of any model of SAD with the use of tracheal tubes (TTs) of any design.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration. Two review authors independently assessed trial quality and extracted data, including information on adverse events. We contacted study authors for additional information. If sufficient data were available, results were presented as pooled risk ratios (RRs) with 95% confidence intervals (CIs) based on random-effects models (inverse variance method). We employed the Chi(2) test and calculated the I(2) statistic to investigate study heterogeneity.

MAIN RESULTS

We identified two eligible studies, both comparing the use of one model of SAD, the ProSeal laryngeal mask airway (PLMA) with a TT, with a total study population of 232. One study population underwent laparoscopic surgery. The included studies were generally of high quality, but there was an unavoidable high risk of bias in the main airway variables, such as change of device or laryngospasm, as the intubator could not be blinded. Many outcomes included data from one study only.A total of 5/118 (4.2%) participants randomly assigned to PLMA across both studies were changed to TT insertion because of failed or unsatisfactory placement of the device. Postoperative episodes of hypoxaemia (oxygen saturation < 92% whilst breathing air) were less common in the PLMA groups (RR 0.27, 95% CI 0.10 to 0.72). We found a significant postoperative difference in mean oxygen saturation, with saturation 2.54% higher in the PLMA group (95% CI 1.09% to 4.00%). This analysis showed high levels of heterogeneity between results (I(2) = 71%). The leak fraction was significantly higher in the PLMA group, with the largest difference seen during abdominal insufflation－a 6.4% increase in the PLMA group (95% CI 3.07% to 9.73%).No cases of pulmonary aspiration of gastric contents, mortality or serious respiratory complications were reported in either study. We are therefore unable to present effect estimates for these outcomes.In all, 2/118 participants with a PLMA suffered laryngospam or bronchospasm compared with 4/114 participants with a TT. The pooled estimate shows a non-significant reduction in laryngospasm in the PLMA group (RR 0.48, 95% CI 0.09 to 2.59).Postoperative coughing was less common in the PLMA group (RR 0.10, 95% CI 0.03 to 0.31), and there was no significant difference in the risk of sore throat or dysphonia (RR 0.25, 95% CI 0.03 to 2.13). On average, PLMA placement took 5.9 seconds longer than TT placement (95% CI 3 seconds to 8.8 seconds). There was no significant difference in the proportion of successful first placements of a device, with 33/35 (94.2%) first-time successes in the PLMA group and 32/35 (91.4%) in the TT group.

AUTHORS' CONCLUSIONS

We have inadequate information to draw conclusions about safety, and we can only comment on one design of SAD (the PLMA) in obese patients. We conclude that during routine and laparoscopic surgery, PLMAs may take a few seconds longer to insert, but this is unlikely to be a matter of clinical importance. A failure rate of 3% to 5% can be anticipated in obese patients. However, once fitted, PLMAs provide at least as good oxygenation, with the caveat that the leak fraction may increase, although in the included studies, this did not affect ventilation. We found significant improvement in oxygenation during and after surgery, indicating better pulmonary performance of the PLMA, and reduced postoperative coughing, suggesting better recovery for patients.

Use of intubation introducers through a supraglottic airway to facilitate tracheal intubation: a brief review

PURPOSE

This article is a narrative review regarding the usage and effectiveness of introducers or catheters to facilitate tracheal intubation through a supraglottic airway (SGA) as an alternative intubation technique in normal and difficult airway management.

SOURCES

Relevant articles were obtained through Medline (1948-July 2011). The articles were subsequently cross-referenced for additional literature, and only articles published in English were included.

PRINCIPAL FINDINGS

In this review, we consider 32 reports using the LMA Classic™, LMA Unique™, LMA ProSeal™, LMA Supreme™, AuraOnce™, and i-gel™ as SGA conduits for intubation. In 13 articles, the use of an Aintree Intubation Catheter was described as an intubation introducer and resulted in high success rates in both elective and emergent situations. Eight studies used a guidewire exchange catheter technique. Although blind intubation using a guidewire resulted in a high failure rate, these studies found that using a bronchoscope improved successful intubation. Ten studies showed that insertion of a gum elastic bougie with a bronchoscope as an intubation introducer has high success rates compared with blind bougie insertion. One article described the use of a small endotracheal tube as an intermediary for tracheal intubation.

CONCLUSIONS

In failed intubation scenarios, supraglottic airways, such as the LMA Classic™ or LMA ProSeal™ can serve as a conduit for tracheal intubation. A number of techniques using introducers or catheters can facilitate the insertion of an adequately sized endotracheal tube, particularly guided by a bronchoscope. Usage of introducers or catheters through a supraglottic airway may be a useful alternative intubation technique in difficult airway management.

Use of the Laryngeal Mask Airway-Aintree Intubating Catheter-fiberoptic bronchoscope technique for difficult intubation

STUDY OBJECTIVE

To determine whether intubation using an Aintree Intubation Catheter (AIC), fiberoptic intubation (FOB), and Laryngeal Mask Airway (LMA) is safe and effective for securing the airway in patients who are difficult to intubate after induction of general anesthesia.

DESIGN

Retrospective review of departmental difficult airway database procedures completed between July 2006 and December 2009.

SETTING

Academic medical center.

MEASUREMENTS AND MAIN RESULTS

During the study period, 128 of 500 patients entered into the difficult airway database underwent the LMA-AIC-FOB technique for intubation. One hundred nineteen (93%) of the 128 patients were successfully intubated by the LMA-AIC-FOB technique, and 9 required an alternate technique. No patient who underwent the LMA-AIC-FOB technique experienced an airway-related mortality or required an emergency surgical airway procedure.

CONCLUSION

The LMA-AIC-FOB technique is safe and effective for patients who are difficult to intubate after induction of anesthesia.

The McIvor blade improves insertion of the LMA ProSeal™ in children

BACKGROUND

The McIvor blade, a tongue retractor with a thin curved blade, is used to improve the operating field during a tonsillectomy. We compared the success rate and incidence of complications between digital insertion and McIvor blade-guided insertion of the laryngeal mask airway (LMA™) ProSeal™ when performed by anesthesia residents in children.

METHODS

A total of 134 anesthetized non-paralyzed pediatric patients were included in the study. Patients were allocated randomly to one of two groups, i.e., Digital group (LMA ProSeal insertion using the digital insertion technique) or McIvor group (LMA ProSeal insertion using the Mclvor blade-guided technique). All patients were managed by anesthesia residents who were unskilled in using each technique. We assessed success rates of insertion at the first attempt, insertion time for an effective airway, and postoperative blood staining.

RESULTS

The success rate of insertion at the first attempt was higher in the McIvor group than in the Digital group (97% vs 78%, respectively; P = 0.003), and insertion time with a successful first attempt was shorter in the McIvor group than in the Digital group (20.5 [4.5] sec vs 22.8 [6.7] sec, respectively; P = 0.021). The overall insertion time for an effective airway was also shorter in the McIvor group than in the Digital group (20.9 [5.7] sec vs 26.0 [9.8] sec, respectively; P < 0.001). Blood staining was more frequent in the Digital group than in the McIvor group (23% vs 6%, respectively; P = 0.035).

CONCLUSION

When inserting the LMA ProSeal in children, anesthesia residents were more successful using the McIvor blade-guided insertion technique than using the digital insertion technique. (ClinicalTrials.gov number, NCT01191619).

Airway exchange catheters use in the airway management of neonates and infants undergoing surgical treatment of laryngeal stenosis

BACKGROUND

Congenital and acquired upper airway obstruction in infants commonly manifests as an acute, potentially life-threatening condition or a slow and gradual deterioration and can be a challenge to the pediatric anesthesiologist. This case series reports the nonconventional use of pediatric airway exchange catheters emergent and short-term airway management and lung ventilation in neonates and infants with severe laryngotracheal stenosis.

CASE SERIES

After the approval of local Institutional Review Board, 11 consecutive patients presenting with severe laryngotracheal stenosis exceeding 70% were prospectively studied. Median (range) age and weight were 32 days (0-96) and 2.7 kg (2.1-3.4), respectively. Induction of anesthesia consisted of sevoflurane 5% in oxygen followed by sevoflurane 3% in an air/oxygen mixture (Fio2 = 0.5). Spontaneous ventilation was maintained in all patients. The trachea was intubated using an Airway Exchange Catheter with an inner diameter of 1.6 mm (Cook Airway Exchange Catheters, Cook Medical, Bloomington, IN). An Airway Exchange Catheter was inserted through the stenosis and manually assisted ventilation was confirmed using capnography. Median (range) ventilation duration was 28 minutes (12-61 mins). In one neonate, the Airway Exchange Catheter failed to ensure proper ventilation and an emergency tracheostomy was performed. Respiratory distress was likely due to a significant increase in airway resistance at the stenosis level or distal accumulation of secretions.

CONCLUSION

Airway exchange catheters represent a useful additional tool for short-term advanced airway management for both oxygenation and ventilation in neonates and infants presenting with severe laryngotracheal stenosis.

Retrograde intubation

Airway management in the emergency department is a critical skill that must be mastered by emergency physicians. When rapid-sequence induction with oral-tracheal intubation performed by way of direct laryngoscopy is difficult or impossible due to a variety of circumstances, an alternative method or device must be used for a rescue airway. Retrograde intubation requires little equipment and has few contraindications. This technique is easy to learn and has a high level of skill retention. Familiarity with this technique is a valuable addition to the airway-management armamentarium of emergency physicians caring for ill or injured patients. Variations of the technique have been described, and their use depends on the individual circumstances.

Evaluation of the revised laryngeal tube suction: the laryngeal tube suction II in 100 patients

BACKGROUND

We prospectively assessed the performance of the laryngeal tube suction mark II (LTS II).

METHODS

LTS II was assessed during controlled and spontaneous ventilation during total i.v. anaesthesia. Ventilation adequacy, functional and anatomical positioning and airway seal were evaluated.

RESULTS

One hundred healthy patients (30F:70M) aged 18-85-yr-old were studied. Insertion of the LTS II was successful in 71 at first attempt, in 24 at second attempt and in five at third/fourth attempt. Median insertion time was 15 s (range 5-120 s). Temporary obstruction occurred in six patients. A median of one manipulation per patient was required to establish an airway (range 0-5). During maintenance, temporary airway obstruction occurred in eight patients. Use of the device was abandoned once during insertion, once during maintenance and once because of complications unrelated to the study. The airway was clear in 89 of 97 patients during maintenance and partially obstructed in eight. Median seal pressure was 29.5 (range 15-85) cm H2O. A gastric tube was passed via the posterior channel in 97 of 99 patients. The glottis was visible using a fibrescope passed via the device in 51% of patients. Via the drain tube the upper oesophagus was visible in 22% and this was open in 50%. Blood was visible on the device after removal in 12 patients. After the operation 14 patients reported mild sore throat.

DISCUSSION

The LTS II appears to be an improvement on its predecessor and merits further investigation comparing it with its competitors during use for anaesthesia and emergency airway management.

A comparison of the laryngeal tube-S and Proseal laryngeal mask during outpatient surgical procedures

BACKGROUND AND OBJECTIVE

The Laryngeal Tube Sonda (LTS) and the ProSeal Laryngeal Mask Airway (PLMA) are two new devices introduced for maintaining the airway during controlled ventilation under general anaesthesia. The present investigation compared their performance in a randomized controlled study.

METHODS

One hundred ASA I-II patients, aged 18-60 yr undergoing elective minor surgery, were randomized to receive either an LTS (n = 50) or PLMA (n = 50) for airway management. After induction of general anaesthesia, the devices were inserted, its correct placement was verified and airway leak pressure was measured. Ease of insertion, quality of airway seal, fibre-optic view and postoperative pharyngeal morbidity were examined.

RESULTS

There were no differences in patient characteristics for both groups. First-time and second-time success rates were comparable for both groups (86 vs. 88% and 96 vs. 98% in LTS and PLMA groups, respectively). The airway of one patient in each group could not be managed with these devices after three attempts. Time until delivery of first tidal volume for LTS and PLMA was 24.5 +/- 6.9 and 28.8 +/- 10.3 s. Fixation and manipulation time was 54.9 +/- 15.2 and 73.2 +/- 25 s, respectively (P < 0.05). Airway seal pressure (cm H(2)O) for LTS and PLMA was 20 +/- 8.6 and 24.1 +/- 10.8, respectively (P = 0.04). Patients were questioned on a variety of postoperative pharyngeal morbidities. Only hoarseness was more frequent in the LTS group.

CONCLUSIONS

Both devices provide a secure airway, are similar in clinical utility and are easy to insert. Better airway seal was detected in the PLMA group.

Analysis of 1000 consecutive uses of the ProSeal laryngeal mask airway by one anaesthetist at a district general hospital

BACKGROUND

The ProSeal laryngeal mask airway (PLMA), introduced to UK practice in late 2001, offers potential performance and safety benefits over other airways such as the classic laryngeal mask airway. There are no large series reporting its use.

METHODS

Data from a prospective, consecutive series of 1000 size 3-5 PLMA uses, by one anaesthetist, were analysed to examine whether performance in routine and advanced practice is similar to that reported in formal trials.

RESULTS

Patients were female in 52% of cases, median age 52 (range 8-101) yr, median weight 78 kg (10% over 100 kg, 24% over 90 kg). Procedures included 12% laparoscopic and 5% open abdominal surgery. Overall insertion success was 99.4%, (first and second attempt success 85% and 12%, respectively). Median insertion time was 12 s (93% <30 s). Insertion success did not differ between genders, or between mask sizes. Median airway seal was 32 cm H(2)O (range 8-40, 94% seal >20 cm H(2)O). Specific tests confirmed correct positioning in 98.5% of cases. Of six failures, two occurred during management of difficult airways. Minor airway obstruction occurred in 2.7%. Blood was visible on 8% of removed PLMAs and more commonly after more than one insertion attempt (38 vs 4.7%, chi(2) P < 0.0001). In three cases minor regurgitation without aspiration occurred.

CONCLUSIONS

In the hands of a regular user, the PLMA was associated with a high rate of insertion success during routine and advanced use in relatively unselected patients. Correct placement rates approached 100%. The incidence of complications was low.

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.

Tracheal intubation via the Classic™ and Proseal™ laryngeal mask airways: a manikin study using the Aintree Intubating Catheter

Fibreoptic-assisted tracheal intubation with an Aintree Intubating Catheter via a dedicated airway is sometimes recommended when conventional tracheal intubation fails. This study compares the use of the Classic and Proseal laryngeal mask airways (LMA) for this purpose in a manikin. Twenty-five anaesthetists of all grades performed two intubations with each device. The overall success rate was 95%. The procedure took < 90 s in all cases and < 60 s in 88% of patients. The speed of intubation increased from the first to fourth attempt and between the first and second attempt with each device (p < 0.001). Allowing for the learning effects observed with each device, there was no statistically significant difference found when comparing speed of intubation with the two devices (p > 0.05). There was no significant difference between the devices with regard to ease of advancement of the fibrescope or the view of the vocal cords with the Aintree Intubating Catheter. Four failures occurred with the LMA Classic and one with the LMA Proseal. Subjective comments favoured the LMA Proseal (p < 0.05), although the clinical importance of these comments is difficult to determine. This study has shown that, in a manikin, fibreoptic guided intubation via an LMA Proseal is at least as easy and reliable as through an LMA Classic. In view of the potential advantages of the LMA Proseal for airway rescue and management of the difficult airway, this study suggests a clinical evaluation of the use of the combination of an LMA Proseal and an Aintree Intubating Catheter in patients is justified.

Non-conventional uses of the Aintree Intubating Catheter in management of the difficult airway

We present 14 cases, of which three have been previously reported, in which non-conventional use was made of the Aintree Intubating Catheter (AIC). In seven cases the AIC was used via a ProSeal Laryngeal mask airway (PLMA). Two patients had anticipated difficult intubation, two unexpected difficult intubation and two required rescue of an obstructed airway prior to AIC-assisted intubation. In two cases of tracheal stenosis the AIC was used as a 'long narrow tracheal tube' during fibre-optic intubation: the AIC facilitated passage through the narrowed trachea and smooth railroading of a tracheal tube. In two cases the AIC was used in an awake patient. In three cases the AIC was used successfully despite gross laryngeal oedema. In three cases attempted AIC deployment failed: two patients had undergone radiotherapy to the mouth and PLMA placement failed; in the third, supraglottic oedema prevented visualisation of the larynx. The AIC via an LMA Classic was successful in one of these cases. In all cases where the larynx was visualised the AIC was rapidly successful without complications. In eight cases the anaesthetist had no experience of the technique outside workshops. These cases demonstrate general utility of the technique and successful use of the AIC via the PLMA, in awake patients, as an adjunct to fibre-optic intubation and in patients with an oedematous larynx. Finally, cases where the combination of the PLMA and AIC was unsuccessful demonstrate the technique, like many, is not always successful.

A complication of transtracheal jet ventilation and use of the Aintree intubation catheter during airway resuscitation

We report the management of a patient requiring surgical laryngoscopy with a view to laser resection of an epiglottic recurrence of laryngeal cancer. Previous attempts at tracheal intubation and awake nasal fibreoptic intubation had failed. During a previous anaesthetic the patient had been both 'impossible to intubate and to ventilate'. Neck scarring potentially complicated access for transtracheal jet ventilation. Nevertheless, a cricothyroid catheter was placed and surgery performed during low frequency 'volume' jet ventilation. Upper airway obstruction developed during the procedure, preventing exhalation, which led to raised intrathoracic pressure, cardiovascular collapse and barotrauma. The airway was re-established by insertion of an LMA Proseal. Fibreoptic placement of an Aintree intubation catheter through this allowed re-oxygenation and exchange for a cuffed tracheal tube. Some hours after the procedure, re-intubation was necessary. This was achieved using the Aintree intubation catheter as an aid to nasal fibreoptic intubation and as a tube exchanger. Novel roles of the Aintree intubation catheter and LMA Proseal in this case are discussed. Complications of transtracheal jet ventilation as well as possible methods for avoiding them are also reviewed.

New airways for resuscitation?

Over the last 15 years supraglottic airway devices (SADs), most notably the classic laryngeal mask airway (LMA) have revolutionised airway management in anaesthesia. In contrast for resuscitation, both in and outside hospital, facemask ventilation and tracheal intubation remain the mainstays of airway management. However there is evidence that both these techniques have complications and are often poorly performed by inexperienced personnel. Tracheal intubation also has the potential to cause serious harm or death through unrecognised oesophageal intubation. SADs may have a role in airway management for resuscitation as first responder devices, rescue devices or for use during patient extraction. In particular they may be beneficial as the level of skill required to use the device safely may be less than for the tracheal tube. Concerns have been expressed over the ability to ventilate the lungs successfully and also the risk of aspiration with SADs. The only SADs recommended by ILCOR in its current guidance are the classic LMA and combitube. Several SADs have recently been introduced with claims that ventilation and airway protection is improved. This pragmatic review examines recent developments in SAD technology and the relevance of this to the potential for using SADs during resuscitation. In addition to examining research directly related to resuscitation both on bench models and in patients the review also examines evidence from anaesthetic practice. SADS discussed include the classic, intubating and Proseal LMAs, the combitube, the laryngeal tube, laryngeal tube sonda mark I and II and single use laryngeal masks.