Comparison of results from novice and trained personnel using the Macintosh laryngoscope, Pentax AWS®, C-MAC™ and Bonfils intubation fibrescope: a manikin study

<p><b>INTRODUCTION</b>Indirect laryngoscopes offer improved laryngeal view and higher success rates of intubation, particularly for difficult airways. We hypothesised that: (a) the time required for intubation, overall success rates and ease of intubation with indirect laryngoscopes would be better than with the Macintosh laryngoscope; and (b) novices may achieve higher success rates and intubate faster using indirect laryngoscopes.</p><p><b>METHODS</b>In a cross-sectional observational study, 13 novices and 13 skilled anaesthetists were recruited. Participants were compared when intubating a manikin simulating normal and difficult airway scenarios using the Macintosh laryngoscope, Pentax Airway Scope® (AWS), C-MAC[TM] and Bonfils intubation fibrescope.</p><p><b>RESULTS</b>There was no significant difference in intubation success rates between the groups. Skilled anaesthetists intubated faster than novices with Pentax AWS in the difficult airway scenario (22 s vs. 33 s, p = 0.047). The mean intubation times for C-MAC and Pentax AWS were shorter than for the Macintosh laryngoscope and Bonfils intubation fibrescope in both difficult (C-MAC: 24 s, Pentax AWS: 28 s, Macintosh: 80 s, Bonfils: 61 s; p < 0.001) and normal (C-MAC: 17 s, Pentax AWS: 19 s, Macintosh: 39 s, Bonfils: 38 s; p = 0.002) airway scenarios.</p><p><b>CONCLUSION</b>We found that intubation success was more than 85% with all indirect laryngoscopes compared to 69% for the Macintosh laryngoscope. Both C-MAC and Pentax AWS achieved faster intubation times compared to the Macintosh laryngoscope and Bonfils intubation fibroscope for both airway scenarios. Skilled anaesthetists were 33% faster than novices when intubating a difficult airway using Pentax AWS.</p>

Anatomical variations of the internal jugular vein: implications for successful cannulation and risk of carotid artery puncture

<p><b>INTRODUCTION</b>Complications occur in over 15% of central venous cannulations, often a result of anatomical variations. This study aimed to determine the anatomical variations of the internal jugular vein (IJV), demonstrate the likely success of cannulation and assess the risk of carotid artery (CA) injury when catheterising the IJV using the external landmarks technique at various degrees of head rotation in the local population.</p><p><b>METHODS</b>100 elective cardiac surgical patients were prospectively enrolled. Simulated catheterisations were performed with patients placed in the Trendelenburg position. The standard landmark technique was used to identify anatomy. Simulations were done at six different degrees of rotation of the head: 0°, 30° and 60° for both right and left IJVs. Difficult catheterisation was defined as an IJV diameter < 7 mm.</p><p><b>RESULTS</b>There was no thrombosed or absent IJV in any patient. Catheterisation was potentially difficult in 15% of patients at 30° head rotation and more difficult for the left IJV than the right (20% vs. 10%; p < 0.05). The simulated needle hit the IJV in 82% of the attempts, but the needle was in the middle 80% of the vein only 70% of the time. Neck rotation increased the degree of overlap of the CA relative to the IJV from 20%-30% to 50%.</p><p><b>CONCLUSION</b>Anatomical variations play a significant role in determining the success of IJV catheterisation as well as the incidence of catheterisation-associated complications. This study emphasises the importance of using ultrasonography to guide IJV catheterisation, even in patients with seemingly normal neck anatomy.</p>