Comparison of Aintree and Fastrach techniques for low-skill fibreoptic intubation in patients at risk of secondary cervical injury: a randomised controlled trial.

BACKGROUND: We compared two methods of asleep fibreoptic intubation in patients at risk of secondary cervical injury: the Aintree Intubation Catheter via a classic laryngeal mask airway (cLMA) versus the Fastrach technique via the intubating laryngeal mask airway (iLMA). OBJECTIVE: To test which system has the highest rate of successful intubations in the clinical setting. DESIGN: A randomised controlled study. SETTING: Single-centre, between 2007 and 2010. PATIENTS: We randomly allocated 80 patients (30 women and 50 men) who underwent elective neurosurgery of the cervical spine to either group, placed in a neutral position and wearing a soft cervical collar. Entry criteria were ASA status 1 to 3, age 18 to 80 years and written informed consent. Exclusion criteria were patients with cervical instability, known or predicted difficult airway, BMI greater than 40  kg  m⁻² and symptomatic gastro-oesophageal reflux. INTERVENTIONS: Two anaesthetists who were experienced in both techniques performed all anaesthesia procedures within the study. There was a maximum of three attempts for performing each technique. MAIN OUTCOME MEASURES: The primary outcome was the rate of successful fibreoptic intubation in a neutral position. We also investigated the timing sequence for both techniques, the Brimacombe and Berry Bronchoscopy Score, and differences in technical aspects. RESULTS: All 40 patients in the Aintree group but only 31 patients in the Fastrach group were intubated successfully. Thus, fibreoptic intubation failed significantly less using the Aintree technique (P = 0.002). For secondary outcomes, the cLMA was faster (260 versus 289  s, P = 0.039) and easier (P = 0.036) to insert than the iLMA. The fibreoptic view of the glottis according to the Brimacombe and Berry Bronchoscopy Score was better (P = 0.016) and the tracheal tube was easier to insert (P = 0.010) in the Aintree group. CONCLUSION: Fibreoptic intubation using the Aintree system was more successful than the Fastrach technique in our population of patients in a neutral position wearing a soft cervical collar. The differences in the time to successful intubation between the two groups are unlikely to be clinically relevant.

Awake fiberoptic intubation and self-positioning in patients at risk of secondary cervical injury: a pilot study.

BACKGROUND: This study was designed to document the feasibility of self-positioning after awake fiberoptic intubation of the trachea using primarily effective topical anesthesia rather than sedation. METHODS: We investigated 14 patients (ASA physical status 1 to 3) with a neurosurgical diagnosis of cervical instability or at risk of secondary cervical injury, who were scheduled for awake fiberoptic intubation and self-positioning prone. Topical anesthesia was accomplished using an oropharyngeal spray of lidocaine alone or in combination with a transtracheal injection of lidocaine for awake fiberoptic intubation and self-positioning prone. Patients evidencing anxiolysis were given midazolam 2 to 4 mg, i.v.. We assessed the need for sedation, tolerance of the endotracheal tube, patient comfort, incidence of coughing or gagging, and changes in heart rate, blood pressure, and oxygen saturation. In addition, patients were interviewed on the first postoperative day and asked to categorize the experience of awake intubation and positioning as a positive, neutral, or negative experience, or to have no recall. RESULTS: Eleven of the 14 patients turned themselves prone after awake fiberoptic intubation. No additional sedation was necessary for accomplishing positioning. Whereas 50% of the patients (7/14) showed mostly slight coughing or gagging during fiberoptic intubation, none of the patients who were positioned awake had coughing or gagging during tube fixation and prone positioning. The technique was unsuccessful in 3 patients. None of the patients viewed this as a negative experience. CONCLUSIONS: Our study demonstrates that awake fiberoptic intubation and patient self-positioning was feasible in this sample of patients at risk of secondary cervical injury. This technique may extend the opportunity of continuous neurological monitoring in patients with a risk of position-related cervical injury, especially where electrophysiological monitoring is not possible or is unavailable.

Recordings of long-latency trigeminal somatosensory-evoked potentials in patients under general anaesthesia.

OBJECTIVE: The reliability of intra-operative recordings of trigeminal scalp-induced somatosensory-evoked potentials (T-SSEP) is controversial. This investigation aimed to provide evidence that T-SSEP recordings are stable using standardised neurophysiological methodology and anaesthesiological regime. METHODS: We investigated 99 patients undergoing carotid endarterectomy under total intravenous anaesthesia (propofol/remifentanil infusion). Long-latency T-SSEPs were recorded from the scalp after simultaneously stimulating 2nd and 3rd branches of the trigeminal nerve. The analysis included visual assessments of traces and measurements of latencies and amplitudes of the N13 and P19 peaks of T-SSEP. Furthermore, additional groups of patients were investigated to identify changes in the parameters of T-SSEP that might correspond to different states of anaesthesia and artificial muscle activity. RESULTS: We reproducibly recorded T-SSEP responses in 99 patients with a mean latency of 12.4 ms (SD=0.93) and amplitude of 5.7 µV (SD=4.7). Collateral investigations concerning changes of T-SSEP caused by neuromuscular blockade improved independence of T-SSEP recordings to muscle relaxation in contrast to facial and cervical muscle activity. CONCLUSIONS: We demonstrated the reliability of recording stable intra-operative T-SSEP responses with standardised electrophysiological and anaesthesiological regimes. SIGNIFICANCE: We provided evidence of the non-muscular origin of T-SSEPs recorded from the scalp.