Anesthesia and analgesia
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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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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.
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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
Comparative StudyComparison of THAM and sodium bicarbonate in resuscitation of the heart after ventricular fibrillation in dogs.
Tris (hydroxymethyl) aminomethane (tromethamine or THAM) has been suggested as an effective substitute for sodium bicarbonate (NaHCO3) in the treatment of metabolic acidosis accompanying cardiac arrest. Even though several reports on its appraisal have been published, there is still no clear agreement on its therapeutic value. A double-blind study was therefore lndertaken to compare in 36 dogs the effectiveness of 0.6 M THAM, 0.3 M THAM, and NaHCO3 (0.892 mEq/ml) to correct metabolic acidosis produced during 3 minutes of cardiac fibrillation, followed by a 3-minute period of cardiac compression. ⋯ There was little difference in the effect of either of these drugs on mean aortic pressure and total peripheral vascular resistance. It is concluded that adequate ventilation and effective cardiac compression are still the chief criteria on which the final outcome of cardiac resuscitation depends. Correction of metabolic acidosis is important supportive therapy, but either THAM or NaHCO3 can be used with comparatively equivalent effect.