Comparison of fibrescope guided intubation via the classic laryngeal mask airway and i-gel in a manikin.

We compared the classic laryngeal mask airway and i-gel as adjuncts to fibrescope guided intubation in a manikin. Two methods of intubation were compared with each device: the tracheal tube directly over the fibrescope; and the tracheal tube over an Aintree Intubation Catheter. Thirty-two anaesthetists took part in this randomised crossover study. Each anaesthetist performed two intubations with each method via each device. The mean (SD) time for the first intubation using the tracheal tube over the fibrescope was 43 (24) s with the classic laryngeal mask airway and 22 (9) s with the i-gel (95% CI for the difference 12-30 s, p < 0.0001). The mean (SD) times for the first intubation when using the Aintree Intubation Catheter was 46 (24) s with the classic laryngeal mask airway and 37 (9) s with the i-gel (95% CI for the difference 5-12 s, p < 0.0001). We recorded five (5/64, 8%) oesophageal intubations when using the classic laryngeal mask airway and none when using the i-gel. The participants rated the ease of railroading of the tracheal tube and railroading the Aintree Intubation Catheter over the fibrescope to be significantly easier (p < 0.0001 and p = 0.002 respectively) when using the i-gel than when using the classic laryngeal mask airway. Furthermore, 30/32 (94%) of anaesthetists reported preference for the i-gel over the classic laryngeal mask airway for fibrescope guided tracheal intubation when managing a difficult airway. We conclude that the i-gel is likely to be a more appropriate conduit than the classic laryngeal mask airway for fibrescope guided intubation irrespective of the intubation method used.

Fibreoptic intubation through the laryngeal mask airway: effect of operator experience*.

SUMMARY: In a randomised crossover study, we compared times and success rates for tracheal placement of a fibrescope and railroading of a tracheal tube through the classic laryngeal mask airway by anaesthetists with limited experience in fibreoptic intubation (trainees) and those who were experts. Thirty-two patients, 32 trainees and three experts took part. The median (IQR [range]) times to fibrescope placement for trainees and experts were 21 (18-30 [12-58]) s and 17 (14-24 [9-55]) s, respectively (95% CI for the difference 2-8 s; p = 0.023). There were no significant differences between trainees and experts in the times to placement of the laryngeal mask airway (41 (33-47 [31-105]) s and 36 (33-43 [30-52]) s, respectively; p = 0.24), railroading times (43 (40-58 [33-87]) s and 44 (38-57 [31-83]) s, respectively; p = 0.96) and total intubation time (114 (97-127 [80-213]) s and 95 (89-116 [74-139]) s, respectively; p = 0.13). There was no significant difference in the number of attempts needed for successful placement of the fibrescope (p = 0.12) and railroading the tracheal tube (p = 0.22). The differences between experts and trainees when using fibrescope assisted intubation via the classic laryngeal mask airway were not clinically important.

Evaluation of tracheal tube introducers in simulated difficult intubation.

In a randomised cross-over study, 72 anaesthetists attempted to place Pro-Breathe, new Portex, and Frova single-use tracheal tube introducers and an Eschmann multiple-use introducer in the trachea of a manikin set to simulate a grade 3 laryngeal view. Successful placement (proportion, 95% confidence interval) of either the Frova (78%, 67-86%) or the Eschmann introducer (64%, 52-74%) was significantly more likely (p < 0.0001) than with the Pro-Breathe (4%, 1-12%) or the new Portex introducer (13%, 7-22%). The difference between the success rates for the Frova and the Eschmann introducers (p = 0.08) was not significant. A separate experiment revealed that the peak force that could be exerted by the Pro-Breathe, new Portex and Frova single-use introducers were three to six times greater than that which could be exerted by the Eschmann introducer (p < 0.0001). The single-use introducers are more likely to cause tissue trauma during placement, particularly if held close to the tip.

Evaluation of clinical effectiveness of the Frova single-use tracheal tube introducer.

A prospective observational study design was used to evaluate the clinical effectiveness of the Frova single-use tracheal tube introducer. Data were collected from 203 patients. Consultants and trainee anaesthetists completed 61 (30%) and 142 (70%) forms respectively, when the Frova introducer was used. It was successfully placed in the trachea in 194/203 (96%) of patients with two attempts at placement by the first clinician. The first clinician failed to either pass the Frova introducer or railroad the tube in six (3%) and 10 (5%) of the 203 patients respectively. The success rate by the first clinician was significantly influenced by the laryngeal view obtained (p < 0.0001). There was only one failure to place the Frova introducer in the trachea by either the first or second clinician. Airway trauma was detected in 11/203 (5%) patients. In six of these 11 patients blood was detected on tracheal suction; 'distal hold up' was elicited in five of these six. The Frova introducer has a high success rate for tracheal placement but has noteworthy potential to produce airway trauma.

Fibreoptic intubation using three airway conduits in a manikin: the effect of operator experience.

In a randomised cross-over study, 72 anaesthetists (24 Senior House Officers, 24 Specialist Registrars and 24 Consultants) attempted to place a fibreoptic scope in the trachea of a manikin using three airway conduits: the Berman airway, the LMA Classic(trade mark) and the intubating laryngeal mask airway. The time for insertion of the airway conduit, delivery of two breaths and fibreoptic scope placement in the trachea was the primary endpoint. These overall times were significantly shorter (median [interquartile range]) using the LMA Classic (36 [28-45]) than via the intubating laryngeal mask (54 [42-79]) and the Berman airway (45 [33-80]), p < 0.0001. Senior House Officers were significantly slower than both Specialist Registrars and Consultants (p < 0.0001). The LMA Classic was considered to be the easiest conduit to use for fibreoptic scope placement by all grades of anaesthetists. We conclude that the LMA Classic is the most effective conduit for fibreoptic scope placement especially for anaesthetists with limited experience in its use.

A comparison of the use of Trachlight and Eschmann multiple-use introducer in simulated difficult intubation.

BACKGROUND AND OBJECTIVE: The Eschmann multiple-use introducer is widely used in the management of difficult intubations. Transillumination of the neck is less commonly used. We conducted a randomized crossover study comparing the Trachlight lightwand and Eschmann multiple-use introducer in simulated difficult intubation. METHODS: Sixty-four healthy patients were studied using a standard anaesthetic and full muscle relaxation assessed by train of four. A Macintosh laryngoscope was then inserted and then lowered to simulate a Grade 3 view. Tracheal placement was attempted with both Trachlight lightwand and Eschmann multiple-use introducer in a randomized order. Anaesthetists placing the devices had extensive experience with the Eschmann multiple-use introducer, but only 15 previous uses of the Trachlight. Success rates and time for tracheal placement were recorded. RESULTS: The Eschmann multiple-use introducer and Trachlight were successfully placed in 96.8% and 93.7%, respectively (n.s.). Mean (SD) time to intubation for Eschmann multiple-use introducer and Trachlight were 15(6) and *21(13), respectively (*P < 0.001). CONCLUSION: The Trachlight is a potentially useful alternative to the Eschmann multiple-use introducer in difficult intubation.

A comparison of direct laryngoscopy and jaw thrust to aid fibreoptic intubation.

We compared two manoeuvres, jaw thrust and laryngoscopy, to open the airway during fibreoptic intubation in 50 patients after induction of anaesthesia in a crossover study. Patients were randomly allocated to receive either jaw thrust or conventional Macintosh laryngoscopy first. Airway clearance was assessed at both the soft palate and the epiglottis. Direct laryngoscopy provided significantly better airway clearance at the level of the soft palate than jaw thrust (44 (88%) vs 31 (62%), respectively; p = 0.002). At the level of the larynx, airway clearance was equally good in both groups (45 (90%) vs 46 (92%), respectively; p = 0.56). The times to view the larynx (median (interquartile range [range]) 4 (3-5 [2-35]) s vs 3 (3-4 [2-8]) s, respectively) and intubation time (20 (17-23 [11-83]) s vs 18 (15-20 [11-28]) s, respectively) were also similar.

Prehospital airway management in Ambulance Services in the United Kingdom.

A postal survey of the 38 Ambulance Services in the United Kingdom was undertaken to find out what equipment is provided for paramedic crews to aid tracheal intubation and to confirm tracheal placement. The response rate to our survey was 100%. Fourteen (37%) ambulance services provided neither stylet nor bougie to facilitate difficult intubation. The laryngeal mask airway was available to 15 (40%) ambulance services. Seventeen (45%) ambulance services had use of a needle cricothyroidotomy set. Twenty-nine (76%) ambulance services had no type of device other than a stethoscope to confirm tracheal tube placement. This survey showed wide variations in the equipment for airway management available to paramedic crews in the United Kingdom. We recommend provision of a standard set of airway management equipment to all paramedic crews in the United Kingdom together with introduction of appropriate training programmes.

Evaluation of Frova, single-use intubation introducer, in a manikin. Comparison with Eschmann multiple-use introducer and Portex single-use introducer.

In a randomised cross-over study, 48 anaesthetists attempted to place a Frova single-use introducer, an Eschmann multiple-use introducer and a Portex single-use introducer in the trachea of a manikin set up to simulate a grade 3 laryngoscopic view. The anaesthetists were blinded to success (tracheal placement) or failure (oesophageal placement). Successful placement (proportion, 95% confidence interval) of either the Frova introducer (65%, 50-77%) or the Eschmann introducer (60%, 46-73%) was significantly more likely than with the Portex introducer (8%, 3-20%). There were no significant differences between the success rates for the Frova and the Eschmann introducers. A separate experiment revealed that the peak force exerted by the Frova and Portex introducers was two to three times greater than that which could be exerted by the Eschmann introducer, p < 0.0001, indicating that the single-use introducers are more likely to cause tissue trauma during placement.

Changes in cerebral oxygenation during cold (28 degrees C) and warm (34 degrees C) cardiopulmonary bypass using different blood gas strategies (alpha-stat and pH-stat) in patients undergoing coronary artery bypass graft surgery.

BACKGROUND: Impaired cerebral oxygenation, which is reflected by measuring jugular bulb oxygenation, is thought to play an important role in the development of neurological injury after cardiac operations with cardiopulmonary bypass (CPB). The effects of cardiopulmonary temperature and blood gas strategy on cerebral oxygenation are not fully appreciated. METHODS: Sixty patients were randomly allocated into four equal groups (cold alpha-stat, cold pH-stat, warm alpha-stat and warm pH-stat) to compare the effect of these perfusion strategies on cerebral oxygenation monitored by jugular bulb oximetry [jugular bulb oxygen saturation (SjO(2)) and arterial-jugular bulb oxygen content difference (AjDO(2))]. Jugular bulb oxygen saturation and AjDO(2) were measured before CPB, after 5, 20, 40 min on CPB, at start and end of rewarming, 5 min before the end of CPB and 10 min after CPB. Two-way analysis of variance was used to model the lowest SjO(2) and highest AjDO(2) during CPB, with CPB temperature and blood gas management as contributing factors. RESULTS: Significant changes in SjO(2) were only related to the type of blood gas management, with no significant difference between warm and cold CPB patients. In addition, during rewarming, desaturation (SjO(2)

Difficult Airway Society guidelines for management of the unanticipated difficult intubation.

UNLABELLED: Problems with tracheal intubation are infrequent but are the most common cause of anaesthetic death or brain damage. The clinical situation is not always managed well. The Difficult Airway Society (DAS) has developed guidelines for management of the unanticipated difficult tracheal intubation in the non-obstetric adult patient without upper airway obstruction. These guidelines have been developed by consensus and are based on evidence and experience. We have produced flow-charts for three scenarios: routine induction; rapid sequence induction; and failed intubation, increasing hypoxaemia and difficult ventilation in the paralysed, anaesthetised patient. The flow-charts are simple, clear and definitive. They can be fully implemented only when the necessary equipment and training are available. The guidelines received overwhelming support from the membership of the DAS. DISCLAIMER: It is not intended that these guidelines should constitute a minimum standard of practice, nor are they to be regarded as a substitute for good clinical judgement.

Bougie-assisted difficult airway management in a manikin - the effect of position held on placement and force exerted by the tip.

In a randomised cross-over study, 50 anaesthetists attempted to place a multiple-use bougie in the trachea of a manikin, when holding it at either 20 cm or 30 cm from the tip. A grade 3 laryngoscopic view was simulated. The anaesthetists were blinded to success (tracheal placement) or failure (oesophageal placement). The success rates when held at 20 and 30 cm distance from the tip were 68 and 62%, respectively (p = 0.55). In a separate experiment, multiple and single-use bougies were held at four different positions and pressed onto a disc attached to a force transducer. The peak force exerted by the single-use bougies was two to three times greater than that which could be exerted by the multiple-use bougies (p < 0.0001). Holding the bougie at either 20 or 30 cm distance from the tip is unlikely to influence bougie placement. The single-use bougie is much more likely to cause trauma to tissue during placement, particularly if held close to the tip.