Effect of Different Insertion Methods on LMA Protector-Related Complications: A Prospective Randomized Double-Blind Clinical Trail.

OBJECTIVE: The authors compared the effect of 2 insertion methods, namely the conventional laryngeal mask airway (LMA) insertion and the index finger-assisted LMA insertion, on the incidence of complications associated with LMA Protector insertion. METHODS: The authors enrolled 300 patients, who underwent painless bronchoscopy. The patients ranged in age between 18 and 75 and were classified as American Society of Anesthesiologists grade I to III. They were randomly divided into 2 groups: a control group of 150 patients and an assisted group comprising 150 patients. LMA was inserted using the conventional and index finger-assisted insertion methods in both groups, respectively. The primary outcome was postoperative complications, such as oral mucosal injury and pharyngeal pain. Secondary outcomes included the success rate of first-time insertion, the incidence rate of inverse folding of LMA tips, oropharyngeal leak pressure (OLP), and other postoperative complications. RESULTS: Compared with the conventional LMA insertion method, index finger-assisted LMA insertion can significantly reduce the incidence rate of oral mucosal injury and pharyngeal pain, with fewer insertion failures. There was a statistically significant difference between the 2 groups in the visual field grading before adjustment for LMA alignment (P<0.0001). The conventional insertion method increased the likelihood of inverse folding of LMA tips. When the conventional insertion method was utilized, there was a significant difference in airway pressure and tidal volume before and after alignment under a fiberoptic bronchoscope (P<0.0001), but no significant difference in visual field grading and respiratory mechanics-related indicators. CONCLUSIONS: Index finger-assisted insertion can significantly reduce the incidence rate of LMA Protector-related complications and inverse folding of LMA tips.

Comparison of ventilation techniques for compensation of mask leakage using a ventilator and a regular full-face mask: A bench study.

Background: The use of noninvasive ventilation (NIV) during and after extubation is common. We designed this study to determine the optimal strategy to compensate for mask leaks and achieve effective ventilation during NIV by comparing commonly used operating room ventilator systems and a regular facemask. Methods: We tested four operating room ventilator systems (Dägger Zeus, Dägger Apollo, Dägger Fabius Tiro, and General Electric Healthcare Carestation 650) on a lung model with normal compliance and airway resistance and evaluated pressure control ventilation (PCV), volume control ventilation (VCV), and AutoFlow mode (VAF). We set the O2 flow at 10 L/min and the maximal flow at 13, 16, or 26 L/min. We simulated five leak levels, from no leak to over 40 L/min (I to V levels), using customized T-pieces placed between the lung model and the breathing circuit. We recorded the expired tidal volume (Vte) from the lung model and peak inspiratory pressure via two flow/pressure sensors that were placed distally and proximally to the T-pieces. Results: 1. Comparison of four ventilators: with any given ventilation mode, an increase in leak level caused a decrease in Vte. With PCV, only Zeus produced Vte larger than 150 ml at leak level V. 2. Effect of ventilation mode on Vte: across all four ventilators, PCV resulted in a higher Vte than VCV and VAF (P < 0.01). PCV mode with all ventilators at leak level II provided Vte values that were equal to or greater than those obtained with no leak. 3. Effect of O2 flow on Vte Using PCV mode: only Carestation 650 Vte at leak level II during PCV were significantly greater with 16 L/min O2 flow compared with 10 L/min O2 flow (P < 0.01). 4. Actual leak: increasing the O2 flow from 10 L/min to the maximum O2 flow dramatically increased the real leak with all 4 ventilators at any fixed leak level (P < 0.01). 5. Preset PIP vs. actual PIP with PCV: at low preset PIP and leak levels such as leak II and III, the discrepancy between preset PIP and actual PIP was small. The disparity between the preset and actual PIP grew when the target PIP and the leak level were raised. Conclusion: For NIV using a mask, the ventilator is preferred whose Pressure generator is Turbine, the PCV mode is preferred in the ventilation mode and the oxygen flow is set to 10 L/min or maximum oxygen flow.

Perineural administration of dexmedetomidine in combination with ropivacaine prolongs axillary brachial plexus block.

To evaluate the hypothesis that adding dexmedetomidine to ropivacaine prolongs axillary brachial plexus block. Forty-five patients of ASA I~II and aged 25-60 yr who were scheduled for elective forearm and hand surgery were randomly divided into 3 equal groups and received 40 ml of 0.33% ropivacaine + 1 ml dexmedetomidine (50 µg) (Group DR1), 40 ml of 0.33% ropivacaine + 1 ml dexmedetomidine (100 µg) (group DR2) or 40 ml of 0.33% ropivacaine + 1 ml saline (group R) in a double-blind fashion. The onset and duration of sensory and motor blocks and side effects were recorded. The demographic data and surgical characteristics were similar in each group. Sensory and motor block onset times were the same in the three groups. Sensory and motor blockade durations were longer in group DR2 than in group R (P < 0.05). There was no significant difference in the sensory blockade duration between group DR1 and group R. Bradycardia, hypertension and hypotension were not observed in group R and occurred more often in group DR2 than in group DR1. Dexmedetomidine added to ropivacaine for an axillary brachial plexus block prolongs the duration of the block. However, dexmedetomidine may also lead to side effects such as bradycardia, hypertension, and hypotension.