Anesthesia and analgesia
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Anesthesia and analgesia · Oct 1998
Randomized Controlled Trial Clinical TrialDexamethasone decreases the incidence of shivering after cardiac surgery: a randomized, double-blind, placebo-controlled study.
Shivering after cardiac surgery is common, and may be a result of intraoperative hypothermia. Another possible etiology is fever and chills secondary to activation of the inflammatory response and release of cytokines by cardiopulmonary bypass. Dexamethasone decreases the gradient between core and skin temperature and modifies the inflammatory response. The goal of this study was to determine whether dexamethasone can reduce the incidence of shivering. Two hundred thirty-six patients scheduled for elective coronary and/or valvular surgery were randomly assigned to receive either dexamethasone 0.6 mg/kg or placebo after the induction of anesthesia. All patients received standard monitoring and anesthetic management. After arrival in the intensive care unit (ICU), nurses unaware of the treatment groups recorded visible shivering, as well as skin and pulmonary artery temperatures. Analysis of shivering rates was performed by using chi2 tests and logistic regression analysis. Compared with placebo, dexamethasone decreased the incidence of shivering (33.0% vs 13.1%; P = 0.001). It was an independent predictor of reduced incidence of shivering and was also associated with a higher skin temperature on ICU admission and a lower central temperature in the early postoperative period. ⋯ Dexamethasone is effective in decreasing the incidence of shivering. The effectiveness of dexamethasone is independent of temperature and duration of cardiopulmonary bypass. Shivering after cardiac surgery may be part of the febrile response that occurs after release of cytokines during cardiopulmonary bypass.
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Anesthesia and analgesia · Oct 1998
Randomized Controlled Trial Clinical TrialThe advantages of the lateral decubitus position after spinal anesthesia with hyperbaric tetracaine.
We investigated the effects of lateral decubitus positioning after spinal anesthesia with hyperbaric tetracaine on the spread of sensory blockade and hemodynamic variables. One hundred ASA physical status I or II patients scheduled for elective surgery to the lower limb received spinal anesthesia at a rate of approximately 0.1 mL/s using 0.5% tetracaine in 7.5% glucose with 0.125% phenylephrine in the lateral decubitus position with the operated side dependent. They were randomly divided into three groups: patients in Group I were placed supine immediately after spinal injection; those in Group II remained in the lateral position for 10 min before being turned supine; those in Group III were kept in the lateral position for 20 min then turned supine. Neural block was assessed by cold, pinprick, and touch sensation, and a modified Bromage scale. Hemodynamic variables included blood pressure, heart rate, and the use of ephedrine for the treatment of hypotension. The median (10th, 90th percentiles) peak dermatomal level to pinprick on the dependent side in Group III was T8 (T11, T5), which was significantly lower than that in Groups I and II, which extended to T4 (T9, T3) and T5 (T10, T2), respectively (P < 0.05). The difference in the maximal cephalad spread of sensory blockade between both sides in Group III was only one dermatome but was statistically significant (P < 0.05); in contrast, there was no significant difference in the maximal sensory level between both sides in Groups I and II. The use of ephedrine for the treatment of hypotension was significantly less frequent in Group III than the other groups. We conclude that keeping a patient in the lateral decubitus position for 20 min after hyperbaric tetracaine spinal anesthesia maintains preferential anesthetic distribution to the dependent side. Despite small differences between the two sides, the restricted spread of blockade and less hemodynamic variability may be clinically advantageous. ⋯ The effects of posture on the spread of hyperbaric spinal anesthesia have not been adequately investigated. The results of the present study suggest an advantage of prolonged lateral decubitus positioning after intrathecal hyperbaric tetracaine.
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Anesthesia and analgesia · Oct 1998
Infraclavicular brachial plexus block: parasagittal anatomy important to the coracoid technique.
Infraclavicular brachial plexus block is a technique well suited to prolonged continuous catheter use. We used a coracoid approach to this block to create an easily understood technique. We reviewed the magnetic resonance images of the brachial plexus from 20 male and 20 female patients. Using scout films, the parasagittal section 2 cm medial to the coracoid process was identified. Along this oblique section, we located a point approximately 2 cm caudad to the coracoid process on the skin of the anterior chest wall. From this point, we determined simulated needle direction to contact the neurovascular bundle and measured depth. At the skin entry site, the direct posterior insertion of a needle will make contact with the cords of the brachial plexus where they surround the second part of the axillary artery in all images. The mean (range) distance (depth along the needle shaft) from the skin to the anterior wall of the axillary artery was 4.24 +/- 1.49 cm (2.25-7.75 cm) in men and 4.01 +/- 1.29 cm (2.25-6.5 cm) in women. Hopefully, this study will facilitate the use of this block. ⋯ We sought a consistent, palpable landmark for facilitation of the infraclavicular brachial plexus block. We used magnetic resonance images of the brachial plexus to determine the depth and needle orientation needed to contact the brachial plexus. Hopefully, this study will facilitate the use of this block.
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Anesthesia and analgesia · Oct 1998
Randomized Controlled Trial Clinical TrialThe effect of magnesium sulphate on hemodynamics and its efficacy in attenuating the response to endotracheal intubation in patients with coronary artery disease.
Laryngoscopy and endotracheal intubation may produce adverse hemodynamic effects. Magnesium has direct vasodilating properties on coronary arteries and inhibits catecholamine release, thus attenuating the hemodynamic effects during endotracheal intubation. We studied 36 patients with coronary artery disease (CAD) scheduled for elective coronary artery bypass grafting to evaluate the hemodynamic effects of magnesium and its efficacy in attenuating the response to endotracheal intubation. Patients received either 0.1 mL/kg (50%) magnesium sulfate (50 mg/kg) (Group A, n = 19) or isotonic sodium chloride solution (Group B, n = 17) before the induction of anesthesia and 0.05 mL/kg of isotonic sodium chloride solution (Group A) or lidocaine 2% (1 mg/kg) (Group B) before intubation. The hemodynamic variables were recorded before induction, after the trial drug, after induction, and after endotracheal intubation. Automatic ST segment analysis was performed throughout the study period. Magnesium sulfate administration was associated with increased cardiac index (P < 0.01), a minimal increase in heart rate, and a significant decrease in mean arterial pressure (MAP) and systemic vascular resistance (SVR) (P < 0.001). None of the patients in the magnesium group had significant ST depression compared with three patients in the control group. The magnesium group patients had a significantly lesser increase in MAP (P < 0.05) and SVR (P < 0.01) compared with the control group patients who received lidocaine before endotracheal intubation. Thus, magnesium is an useful adjuvant to attenuate endotracheal intubation response in patients with CAD. ⋯ Endotracheal intubation produces adverse hemodynamic effects, which may be more detrimental in patients with coronary artery disease than in healthy patients. The present study shows that magnesium administered before endotracheal intubation can attenuate this response better than lidocaine.