Predictors of difficult videolaryngoscopy with GlideScope® or C-MAC® with D-blade: secondary analysis from a large comparative videolaryngoscopy trial.

BACKGROUND: Tracheal intubation using acute-angle videolaryngoscopy achieves high success rates, but is not without difficulty. We aimed to determine predictors of 'difficult videolaryngoscopy'. METHODS: We performed a secondary analysis of a data set (n=1100) gathered from a multicentre prospective randomized controlled trial of patients for whom difficult direct laryngoscopy was anticipated and who were intubated with one of two videolaryngoscopy devices (GlideScope(®) or C-MAC(®) with D-blade). 'Difficult videolaryngoscopy' was defined as 'first intubation time >60 s' or 'first attempt intubation failure'. A multivariate logistic regression model along with stepwise model selection techniques was performed to determine independent predictors of difficult videolaryngoscopy. RESULTS: Of 1100 patients, 301 were identified as difficult videolaryngoscopies. By univariate analysis, head and neck position, provider, type of surgery, and mouth opening were associated with difficult videolaryngoscopy (P<0.05). According to the multivariate logistic regression model, characteristics associated with greater risk for difficult videolaryngoscopy were as follows: (i) head and neck position of 'supine sniffing' vs 'supine neutral' {odds ratio (OR) 1.63, 95% confidence interval (CI) [1.14, 2.31]}; (ii) undergoing otolaryngologic or cardiac surgery vs general surgery (OR 1.89, 95% CI [1.19, 3.01] and OR 6.13, 95% CI [1.85, 20.37], respectively); (iii) intubation performed by an attending anaesthestist vs a supervised resident (OR 1.83, 95% CI [1.14, 2.92]); and (iv) small mouth opening (OR 1.18, 95% CI [1.02, 1.36]). CONCLUSION: This secondary analysis of an existing data set indicates four covariates associated with difficult acute-angle videolaryngoscopy, of which patient position and provider level are modifiable.

A randomised controlled trial of radial artery cannulation guided by Doppler vs. palpation vs. ultrasound.

We randomly allocated 749 participants to radial artery cannulation by anaesthetic trainees, guided by Doppler (244), palpation (256) or ultrasound (249). Ultrasound increased the rate of cannulation at the first attempt by 14% (95% CI 5-22%), from 39% with Doppler or palpation, p = 0.002 for both. There were no differences in the rates of cannulation 5 min after the procedure started: 147/244 (60%) with Doppler; 160/256 (63%) with palpation; and 171/249 (69%) with ultrasound, p = 0.13.

Ultrasound visual image-guided vs Doppler auditory-assisted radial artery cannulation in infants and small children by non-expert anaesthesiologists: a randomized prospective study.

BACKGROUND: Cannulation of the radial artery in infants and small children can be challenging, even for the most experienced providers. Utilizing Doppler to aid in radial artery cannulation has been well described. Recent studies have demonstrated the efficacy of ultrasound (US) image-guided vascular access techniques in the paediatric population. The utility of these two techniques, when used by non-expert personnel, has not been studied. METHODS: This is a randomized prospective study to compare the utility of two different radial arterial cannulation techniques in paediatric patients weighing <12 kg: US-guided technique (US group) vs Doppler-assisted technique (Doppler group) when used by trainees with limited experience. The primary objective was to compare the first-attempt success rate between each group. As a secondary objective, success rate within 10 min was compared. RESULTS: The trial was prematurely terminated after 50% of paediatric patients (n=104) were included in the study and 52 of each were randomized to the US or Doppler group. A total of 12 anaesthesia trainees performed radial arterial cannulations. The first-attempt success rate was greater in the US group compared with the Doppler group [17/52 (33%) vs 8/52 (15%), P=0.039, odds ratio (OR): 2.67, confidence interval (CI): 1.03-6.91]. The overall success rate within 10 min was 34/52 (65%) in the US group and 24/52 (46%) in the Doppler group (P=0.048, OR: 2.20, CI: 1.00-4.85). CONCLUSIONS: US-guided radial arterial cannulation in infants and small children provided a greater chance for success at the first attempt compared with the Doppler-assisted technique.