Defining and developing expertise in tracheal intubation using a GlideScope(®) for anaesthetists with expertise in Macintosh direct laryngoscopy: an in-vivo longitudinal study.

Although videolaryngoscopy can provide excellent views of the laryngeal structures as both the primary method of tracheal intubation and as a rescue technique for difficult direct laryngoscopy, the existing literature is inadequate to define expertise or even competence. We observed the performance of nine trainees during 890 intubations, with an additional 72 intubations performed by expert anaesthetists used as a control group. Univariate and multivariate mixed-effects logistic regression models were applied to detect potential predictors of successful intubation and define the number of intubations necessary for a trainee to achieve expertise (> 90% probability of optimal performance). Optimal performance was predicted by single laryngoscope insertion (p < 0.001) and a Cormack and Lehane grade-1 view (p < 0.001), and not by normal lifting force applied to the device (p = 0.15), with expertise reached after 76 attempts. These results indicate that expertise in videolaryngoscopy requires prolonged training and practice.

Upper limb muscular activity and perceived workload during laryngoscopy: comparison of Glidescope(R) and Macintosh laryngoscopy in manikin: an observational study.

BACKGROUND: The interaction between operators and their working environment during laryngoscopy is poorly understood. Numerous studies have focused on the forces applied to the patient's airway during laryngoscopy, but only a few authors have addressed operator muscle activity and workload. We tested whether different devices (Glidescope(®) and Macintosh) use different muscles and how these differences affect the perceived workload. METHODS: Ten staff anaesthetists performed three intubations with each device on a manikin. Surface electromyography was recorded for eight single muscles of the left upper limb. The NASA Task Load Index (TLX) was administered after each experimental session to evaluate perceived workload. RESULTS: A consistent reduction in muscular activation occurred with Glidescope(®) compared with Macintosh for all muscles tested (mean effect size d=3.28), and significant differences for the upper trapezius (P=0.002), anterior deltoid (P=0.001), posterior deltoid (P=0.000), and brachioradialis (P=0.001) were observed. The overall NASA-TLX workload score was significantly lower for Glidescope(®) than for Macintosh (P=0.006), and the factors of physical demand (P=0.008) and effort (P=0.006) decreased significantly. CONCLUSIONS: Greater muscular activity and workload were observed with the Macintosh laryngoscope. Augmented vision and related postural adjustments related to using the Glidescope(®) may reduce activation of the operator's muscles and task workload.

A new difficult airway management algorithm based upon the El Ganzouri Risk Index and GlideScope® videolaryngoscope. A new look for intubation?

BACKGROUND: An El Ganzouri risk index test (EGRI) score of seven and the ability to achieve difficult laryngeal exposure with the GlideScope® may represent a highly predictive decisional threshold. Hence, we hypothesized that a new difficult airways algorithm that is EGRI- and GlideScope®-based may enable tracheal intubation in every patient. METHODS: Thirteen staff practitioners trained in videolaryngoscopic intubation followed the algorithm from 2008 through 2010. Elective and emergency neurosurgical patients assessed as having an EGRI score of seven and higher underwent flexible fiberoptic bronchoscopy (FFB) intubation while conscious. Those with a score of six and lower were intubated with the GlideScope®, excluding patients with morbid obesity or pharyngo-laryngeal or neck tumors. A decision to perform alternative procedures, difficult laryngeal exposure [Cormack and Lehane (CL) grades III-IV], difficult ventilation and failure to intubate were recorded. RESULTS: The decisional rule was applied in 6,276 patients and resulted in six FFB intubations in conscious patients. The overall incidence of CL grade III-IV views was 0.2%. Difficult videolaryngoscopy was found in 14 patients (0.14%) with a score of 6 and lower. Post-hoc examinations of FFB intubations revealed five difficult laryngeal exposures. The positive predictive value was 85.7%, while the negative predictive value was 99.9%. The incidence of difficult ventilation and difficult laryngeal exposure was 0.03%. Two patients with neck tumors were assigned to alternative procedures. CONCLUSION: Adherence to the decisional process of the algorithm and to GlideScope® videolaryngoscopy achieved successful tracheal intubation in our cohort of patients.

Safety and efficacy of ultrasound assistance during internal jugular vein cannulation in neurosurgical infants.

OBJECTIVE: Ultrasound guidance (USG) for internal jugular cannulation is the best solution in difficult settings where paediatric patients are involved. This is an outcome study on efficacy and complications of the USG for the internal jugular vein (IJV) cannulation in neurosurgical infants as well as an ultrasound study of anatomical findings of the IJVs in infants. DESIGN AND SETTINGS: A prospective study conducted in two Academic Neurosurgical hospitals. PARTICIPANTS: In 191 babies (body weight <15 kg), anatomical findings were studied. We performed CVC echo guided placement in 135/191 infants (weighting <10 kg). RESULTS: After a brief training period, both institutions adopted a common protocol and USG device. We obtained successful cannulation in all patients. Carotid puncture (1.5%) was the only main complication registered and minor complications were poor. Time required for cannulation was 12.5 +/- 5.7 min. Anatomical findings (in 191 patients) were IJV laterality in 34.6% cases, IJV antero-lateral in 59.7% and anterior in 5.7%. A linear relation was found between weight and internal jugular vein diameter even if R(2) = 0.43 and the model cannot be used to predict the exact size of the vein. In 62/135 babies weighting <10 kg, anatomical measurements were done in supine and Trendelemburg position. Trendelemburg position increases significantly (P < 0.001) IJV diameter, but not IJV depth. CONCLUSIONS: We considered ultrasound guidance as the first choice in infants because it can enhance IJV cannulation success, safety, and allows one to measure relationships and diameter of the IJV and optimise the central line positioning.

An outcome study on complications using routine ultrasound assistance for internal jugular vein cannulation.

BACKGROUND: Ultrasound guidance for central venous cannulation is advised by recent guidelines, but is not being applied in everyday practice. The purpose of this study was to determine the reduction in complications when applying an ultrasound locating device for internal jugular vein catheterization. METHODS: An observational study was conducted from November 2004 to October 2005 in a tertiary neurosurgical hospital on 300 patients undergoing internal jugular vein cannulation using an ultrasound technique. Patients were not randomized and operators were trained using theoretical and practical courses. Prior to the study, the investigators, who were consultant anaesthesiologists, had to perform at least 20 successful supervised cannulations. RESULTS: Cannulation was successful in all cases. The incidence of arterial puncture was 2.7%, and multiple venous punctures represented the main minor complication (14%). Bivariate analysis of the overall complications revealed no significant correlation with age group, American Society of Anesthesiologists' (ASA) classification, body mass index, or position and diameter of the vein. CONCLUSIONS: Ultrasound cannulation of the internal jugular vein minimized complications. These could be avoided when new ultrasound probes and specific needles are introduced.

Predictive value of the El-Ganzouri multivariate risk index for difficult tracheal intubation: a comparison of Glidescope videolaryngoscopy and conventional Macintosh laryngoscopy.

BACKGROUND: The predictive value of the El-Ganzouri risk index (EGRI) for difficult intubation has been evaluated using Macintosh laryngoscopy as reference standard. The Glidescope videolaryngoscope provides improved visualization of the glottis. We studied the predictive value of the EGRI using videolaryngoscopy as reference standard. METHODS: Data from two subsequent groups of patients, intubated with Macintosh laryngoscopy (ML, n = 994) and videolaryngoscopy (VL, n = 843), were retrospectively analysed. The EGRI was taken as index test. The two types of laryngoscopy were adopted as reference for the presence of Cormack and Lehane grading III-IV. For both groups, sensitivity, specificity, and positive and negative post-test probabilities (PTP) were calculated for thresholds on the EGRI scale. Receiver operating characteristic curves and corresponding areas (AUC) were obtained. RESULTS: Sensitivity and specificity were 69.7% and 66.3% at the cut-off value of 2 in the ML group, and 93.3% and 76.6% at the cut-off value of 3 in the VL group. Corresponding positive and negative PTP were 12.81% and 3.15% in the ML group, and 6.73% and 0.16% in the VL group. At the threshold of 4, positive and negative PTP were 31.34% and 4.85% in the ML group. At the threshold of 7, positive and negative PTP were 85.71% and 1.08% in the VL group. The AUC was 0.74 in the ML group and 0.91 in the VL group. CONCLUSIONS: The predictive value of the EGRI may have been underestimated due to limited accuracy of Macintosh laryngoscopy. Using videolaryngoscopy, the EGRI might be reconsidered as a decisional tool.