Anesthesia and analgesia
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Anesthesia and analgesia · Oct 1984
Hemodynamic effects of ketamine in children with congenital heart disease.
Pulmonary and systemic vascular responses to ketamine (2 mg X kg-1, intravenously) were studied during cardiac catheterization in 20 children with congenital heart lesions. Pulmonary and systemic resistances (Rp, Rs), ratios between pulmonary and systemic flows (Qp/Qs), and left to right (L----R) and right to left shunts (R----L) were calculated before and after ketamine administration. ⋯ No patient had any major untoward effects from ketamine administration. It is concluded that the hemodynamic alterations after ketamine administration in children undergoing cardiac catheterization are small and do not alter the clinical status of the patients or the information obtained by cardiac catheterization.
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Anesthesia and analgesia · Oct 1984
Comparative StudyA suitable substitute for 4% cocaine before blind nasotracheal intubation: 3% lidocaine-0.25% phenylephrine nasal spray.
To assess the efficacy of potential substitutes for cocaine as a topical anesthetic before nasal intubation, the authors performed a double-blind study comparing the hemodynamic effects of blind nasotracheal intubation in 75 patients receiving one of three nasal sprays: 4% cocaine (C), a mixture of 3% lidocaine in 0.25% phenylephrine (L-P), and 0.25% phenylephrine alone (P). Three minutes after 0.5 ml of one of the solutions was sprayed into each nostril, anesthesia and paralysis were induced with thiopental (5 mg/kg) followed by succinylcholine (1 mg/kg); immediately after induction, mean arterial pressure (MAP) and heart rate (HR) were recorded. After blind nasotracheal intubation was accomplished, MAP and HR were recorded for 5 min while anesthesia was maintained with 70% N2O in O2. ⋯ Although mean HR decreased during the 5 min after intubation in all groups, this decrease was significantly greater (9.6 +/- 1.4 beats/min) in patients receiving L-P than in those receiving C (3.1 +/- 1.6 beats/min) or P (0.1 +/- 1.7 beats/min) (P less than 0.005). Changes in HR and MAP were similar in patients receiving C and P. There was no significant difference in the incidence or severity of epistaxis among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Oct 1984
Comparative StudyComparison of insulated and uninsulated needles for locating peripheral nerves with a peripheral nerve stimulator.
This study was designed to compare the use of insulated and uninsulated needles with a peripheral nerve stimulator for locating a peripheral nerve in an anesthetized cat. The needles were mounted on a one-dimensional manipulator and both the saphenous and sciatic nerves were located. The tip of the insulated needle was consistently placed on the sciatic nerve. ⋯ Using an insulated needle, the minimum current required to stimulate the nerve occurred when the tip of the needle touched the saphenous nerve. Using an uninsulated needle, the minimum current occurred when the tip was 0.1-0.8 cm past the nerve. The conclusion is that insulated needles more precisely locate the peripheral nerve than uninsulated needles.
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Anesthesia and analgesia · Oct 1984
Comparative StudyElectrical nerve location: numerical and electrophoretic comparison of insulated vs uninsulated needles.
We compared the electrical characteristics of insulated and uninsulated needles in two models that simulate use of a stimulator for nerve localization. With a digital computer, we solved for and graphed the contours of constant electric field strength, defining regions of simulated tissue in which a nerve would become depolarized for a particular stimulation current. ⋯ We also found that the necessary stimulator current is much more dependent on the depth of needle insertion with uninsulated needles than with insulated needles. We conclude that the electrical characteristics of insulated needles are more favorable for successful nerve block.