Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1977
Fade of neurally evoked compound electromyogram during neuromuscular block by d-tubocurarine.
Trains of neurally evoked compound electromyographic responses of the thenar muscles were studied in 20 patients anesthetized with enflurane and N2O and paralyzed with d-tubocurarine. Fade was correlated with stimulus frequency (0.1 to 50 Hz) and degree of neuromuscular block. ⋯ Fade was more observable with deeper block and could best be demonstrated by 5 Hz stimuli. With 50 Hz stimuli, a concomitant facilitation, observable from the beginning of the train, partially compensated for the fade.
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The clinical effectiveness and safety of compounded mixtures of lidocaine + bupivacaine and chloroprocaine + bupivacaine for either epidural or brachial-plexus block was studied in 48 adult patients. Of the several alternatives, chloroprocaine + bupivacaine with epinephrine was found the best choice for patients with typical plasma cholinesterase.
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Continuous positive-pressure ventilation may decrease cardiac output. However, a few reports have separated the effects of positive and end-expiratory pressure (PEEP) from those of mechanical ventilation. Ten surgical patients requiring mechanical ventilatory support had catheters inserted for measurement of right atrial pressure (RAP), pulmonary artery occlusion pressure (PAOP), intrapleural, radial artery, airway, and atrial filling pressures, and cardiac output. ⋯ Atrial filling pressures and cardiac output were unaffected by PEEP but decreased during IPPV (p less than 0.001). Patients receiving IMV maintained negative intrapleural pressure, atrial filling pressure, cardiac output and, therefore, O2 delivery, regardless of PEEP level. The authors conclude that patients requiring mechanical respiratory support, with or without PEEP, may maintain better cardiopulmonary function when allowed some spontaneous ventilatory activity.
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Anesthesia and analgesia · Jan 1977
Spontaneous recovery from nondepolarizing neuromuscular blockade: correlation between clinical and evoked responses.
The effects of nondepolarizing muscle relaxants were allowed to wear off spontaneously in 10 ASA class III and IV patients following major surgery. Neuromuscular and respiratory function were followed by clinical testing and by evoked muscle responses using a train of 4 (TOF) supramaximal stimuli. At a TOF of 70 percent (range 62 to 78%), all patients sustained eye-opening, hand-grasp, and tongue-protrusion, while 9/10 sustained head-lift. ⋯ The increase in VC correlated with the increase in TOF (r = 0.88). There was no correlation between inspiratory force (IF) and TOF, but all patients achieved an IF equal to or greater than -22 cm H2O at 70 percent. Thus, TOF correlates well with clinical signs of neuromuscular and respiratory recovery in this group of patients and complements earlier studies in healthy anesthetized patients and nonmedicated volunteers.