We evaluated the effect of tetanic stimulation (5 s, 50 Hz, 60 mA) on the response to tetanic sti... more We evaluated the effect of tetanic stimulation (5 s, 50 Hz, 60 mA) on the response to tetanic stimulation delivered 2 min (TET@2) and 5 min (TET@5) later in 22 anesthetized patients receiving a vecuronium infusion. Once a consistent mechanomyographic train-of-four ratio was obtained at the adductor pollicis muscle, the first (baseline) tetanic stimulus was delivered. Tetanic sequences were repeated randomly after 2- and 5-min intervals. Tetanic fade was consistent among the study periods: the tetanic fade ratio for the first second of tetanus was 0.35 during baseline tetanic stimulation, 0.32 during TET@2 (P = NS by paired t-test), and 0.33 during TET@5 (P = NS). The respective fade ratios for the entire 5-s period were 0.15, 0.15 (P = NS), and 0.14 (P = NS). In contrast, the peak tetanic height increased from 10.8 mm at baseline to 11.3 mm at TET@2 (P < 0.05), and 11.3 mm at TET@5 (P < 0.05). We conclude that, in light of the consistency exhibited by tetanic fade, the small change in twitch height is clinically insignificant.
Monitoring Neuromuscular Function This video demonstrates the assessment of neuromuscular functio... more Monitoring Neuromuscular Function This video demonstrates the assessment of neuromuscular function after administration of neuromuscular blocking agents. Because these agents can be lethal, clinicians should be familiar with the use of nerve stimulators and monitors in the assessment of neuromuscular function.
To investigate the neurologic mechanisms of acidic local anesthetic-induced low back pain in huma... more To investigate the neurologic mechanisms of acidic local anesthetic-induced low back pain in humans, we administered bupivacaine and buffered saline at acidic or alkalinized pH at the L5 dorsal root ganglion (DRG) of rats via a hole drilled through the transverse process covering the DRG. Behavioral changes were tested before and after bupivacaine or saline administration. Results indicate that acute single-dose infusion of the DRG with bupivacaine (0.5%) at acidic pH (5.5) induced ipsilateral mechanical hyperalgesia that lasted for 7 days. Acute infusion of alkalinized bupivacaine (pH 7.2), however, caused only minor hyperalgesia that lasted <3 days. Similar results were obtained when bupivacaine was replaced with saline. Alternatively, chronic delivery of acidic saline to the DRG via a subcutaneously implanted osmotic pump resulted in a significant decrease in the withdrawal threshold on the ipsilateral hind paw that lasted for 10 days. In rats receiving chronic treatment of the DRG with alkalinized saline, mechanical hyperalgesia lasted for only 3 days. The results demonstrated that acidic bupivacaine deposited at the DRG causes pain and hyperalgesia when the effects of the local anesthetic have dissipated. These findings may explain the limited therapeutic effects of some acidic local anesthetics used for management of cancer-related and chronic back pain. Acidic bupivacaine administered at the L5 lumbar ganglion causes pain and hypersensitivity of the hind paw in the rat. These findings may explain the limited therapeutic effects of some acidic local anesthetics used for treatment of cancer-related and chronic back pain.
During performance of direct laryngoscopy in the difficult-to-visualize airway, several maneuvers... more During performance of direct laryngoscopy in the difficult-to-visualize airway, several maneuvers have the potential to impact glottic visualization, including jaw thrust and cricoid pressure. The effect of these maneuvers on glottic visualization during videolaryngoscopy has not been studied. We evaluated the effect of jaw thrust and cricoid pressure maneuvers on both visualization of the glottis and the area of glottic opening visible during GlideScope-aided videolaryngoscopy. One hundred patients were enrolled in this study. After induction of general anesthesia, videolaryngoscopy was followed by jaw thrust and cricoid pressure maneuvers performed in random order. Laryngeal anatomy was recorded continuously and was saved as digital images following the initial laryngoscopy and after each maneuver. Glottis grade [modified Cormack and Lehane (C&L)] was recorded, as was the total glottic area. There was improvement in glottis grade when utilizing jaw thrust maneuver in comparison to GlideScope videolaryngoscopy alone (31% improved, 4% worsened; P < 0.001). There was no difference in glottis grade when using the cricoid pressure maneuver in comparison with videolaryngoscopy alone (39% improved, 20% worsened; P = 0.19). Glottic opening area, however, was greater when utilizing the jaw thrust maneuver in comparison with videolaryngoscopy alone (P < 0.001), but smaller when utilizing the cricoid pressure maneuver in comparison with videolaryngoscopy alone (P < 0.001). The jaw thrust maneuver was superior to videolaryngoscopy alone in improving the modified C&L grade and the visualized glottic area; however, no significant improvement was noted with cricoid pressure. We therefore recommend the use of jaw thrust as a first-line maneuver to aid in glottic visualization and tracheal intubation during GlideScope videolaryngoscopy.
We evaluated the effect of tetanic stimulation (5 s, 50 Hz, 60 mA) on the response to tetanic sti... more We evaluated the effect of tetanic stimulation (5 s, 50 Hz, 60 mA) on the response to tetanic stimulation delivered 2 min (TET@2) and 5 min (TET@5) later in 22 anesthetized patients receiving a vecuronium infusion. Once a consistent mechanomyographic train-of-four ratio was obtained at the adductor pollicis muscle, the first (baseline) tetanic stimulus was delivered. Tetanic sequences were repeated randomly after 2- and 5-min intervals. Tetanic fade was consistent among the study periods: the tetanic fade ratio for the first second of tetanus was 0.35 during baseline tetanic stimulation, 0.32 during TET@2 (P = NS by paired t-test), and 0.33 during TET@5 (P = NS). The respective fade ratios for the entire 5-s period were 0.15, 0.15 (P = NS), and 0.14 (P = NS). In contrast, the peak tetanic height increased from 10.8 mm at baseline to 11.3 mm at TET@2 (P < 0.05), and 11.3 mm at TET@5 (P < 0.05). We conclude that, in light of the consistency exhibited by tetanic fade, the small change in twitch height is clinically insignificant.
Monitoring Neuromuscular Function This video demonstrates the assessment of neuromuscular functio... more Monitoring Neuromuscular Function This video demonstrates the assessment of neuromuscular function after administration of neuromuscular blocking agents. Because these agents can be lethal, clinicians should be familiar with the use of nerve stimulators and monitors in the assessment of neuromuscular function.
To investigate the neurologic mechanisms of acidic local anesthetic-induced low back pain in huma... more To investigate the neurologic mechanisms of acidic local anesthetic-induced low back pain in humans, we administered bupivacaine and buffered saline at acidic or alkalinized pH at the L5 dorsal root ganglion (DRG) of rats via a hole drilled through the transverse process covering the DRG. Behavioral changes were tested before and after bupivacaine or saline administration. Results indicate that acute single-dose infusion of the DRG with bupivacaine (0.5%) at acidic pH (5.5) induced ipsilateral mechanical hyperalgesia that lasted for 7 days. Acute infusion of alkalinized bupivacaine (pH 7.2), however, caused only minor hyperalgesia that lasted <3 days. Similar results were obtained when bupivacaine was replaced with saline. Alternatively, chronic delivery of acidic saline to the DRG via a subcutaneously implanted osmotic pump resulted in a significant decrease in the withdrawal threshold on the ipsilateral hind paw that lasted for 10 days. In rats receiving chronic treatment of the DRG with alkalinized saline, mechanical hyperalgesia lasted for only 3 days. The results demonstrated that acidic bupivacaine deposited at the DRG causes pain and hyperalgesia when the effects of the local anesthetic have dissipated. These findings may explain the limited therapeutic effects of some acidic local anesthetics used for management of cancer-related and chronic back pain. Acidic bupivacaine administered at the L5 lumbar ganglion causes pain and hypersensitivity of the hind paw in the rat. These findings may explain the limited therapeutic effects of some acidic local anesthetics used for treatment of cancer-related and chronic back pain.
During performance of direct laryngoscopy in the difficult-to-visualize airway, several maneuvers... more During performance of direct laryngoscopy in the difficult-to-visualize airway, several maneuvers have the potential to impact glottic visualization, including jaw thrust and cricoid pressure. The effect of these maneuvers on glottic visualization during videolaryngoscopy has not been studied. We evaluated the effect of jaw thrust and cricoid pressure maneuvers on both visualization of the glottis and the area of glottic opening visible during GlideScope-aided videolaryngoscopy. One hundred patients were enrolled in this study. After induction of general anesthesia, videolaryngoscopy was followed by jaw thrust and cricoid pressure maneuvers performed in random order. Laryngeal anatomy was recorded continuously and was saved as digital images following the initial laryngoscopy and after each maneuver. Glottis grade [modified Cormack and Lehane (C&L)] was recorded, as was the total glottic area. There was improvement in glottis grade when utilizing jaw thrust maneuver in comparison to GlideScope videolaryngoscopy alone (31% improved, 4% worsened; P < 0.001). There was no difference in glottis grade when using the cricoid pressure maneuver in comparison with videolaryngoscopy alone (39% improved, 20% worsened; P = 0.19). Glottic opening area, however, was greater when utilizing the jaw thrust maneuver in comparison with videolaryngoscopy alone (P < 0.001), but smaller when utilizing the cricoid pressure maneuver in comparison with videolaryngoscopy alone (P < 0.001). The jaw thrust maneuver was superior to videolaryngoscopy alone in improving the modified C&L grade and the visualized glottic area; however, no significant improvement was noted with cricoid pressure. We therefore recommend the use of jaw thrust as a first-line maneuver to aid in glottic visualization and tracheal intubation during GlideScope videolaryngoscopy.
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Papers by Sorin Brull