Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2003
Randomized Controlled Trial Clinical TrialThe numeric rating scale and labor epidural analgesia.
A verbal numeric 0-10 rating scale (NRS) is widely used to evaluate pain in research studies, but its usefulness to the clinician is not well established. In this study, we define desire for additional analgesic medication as a clinically relevant outcome in research studies about pain and compare it with the results of the NRS. A post hoc analysis of three studies that we previously conducted concerning labor epidural analgesia was performed. In all three studies, a verbal NRS score was obtained before and 15 min after labor epidural analgesia. At 15 min, the woman was also asked if she wanted more pain medication. We found that very few patients (2%) with a NRS score of 0-1 wanted more medication. When the NRS score was 2 or 3, 51% of the patients wanted more medication, and when the NRS score was >3, almost all patients (93%) wanted more medication. Grouping the final NRS scores into 3 categories (0 or 1, 2 or 3, and >3) is more useful to the clinician than using individual NRS scores. ⋯ This study demonstrated that unless the score of the verbal numeric 0-10 rating scale (NRS) is 0 or 1, most women want more analgesic medication for labor epidural analgesia. Additionally, we found that grouping the NRS values into 3 categories for analysis (0 or 1, 2 or 3, and > 3) is more useful to the clinician than using the full spectrum of NRS scores.
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Anesthesia and analgesia · Jun 2003
Clinical TrialCan the bispectral index be used to predict seizure time and awakening after electroconvulsive therapy?
The electroencephalogram (EEG) bispectral index (BIS) measures the hypnotic component of the anesthetic state and correlates with emergence from general anesthesia. Therefore, we hypothesized that the BIS would be useful in predicting electroconvulsive therapy (ECT)-induced seizure times and awakening from methohexital anesthesia. Twenty-five consenting patients with major depressive disorders underwent 100 maintenance ECT treatments. All patients were premedicated with glycopyrrolate 0.2 mg IV, and anesthesia was induced with methohexital 1 mg/kg IV. The BIS was monitored continuously, and the values were recorded at specific end-points, including before anesthesia (baseline), after the induction of anesthesia (pre-ECT), at the end of ECT (peak), after ECT (suppression), and on awakening (eye opening). The pre-ECT BIS value correlated with the duration of both the motor (r = 0.3) and EEG (r = 0.4) seizure activity (P < 0.05). The peak post-ECT BIS value correlated with the duration of the EEG seizure activity (r = 0.5) (P < 0.05). A positive correlation was also found between the EEG seizure duration and the time to eye opening (r = 0.4) (P < 0.05). However, the BIS values on awakening from methohexital anesthesia varied from 29 to 97 and were <60 in 75% of the cases. We conclude that the BIS value before the ECT stimulus is applied could be useful in predicting the seizure time. However, the BIS values on awakening were highly variable, suggesting that it reflects both the residual depressant effects of methohexital and post-ictal depression. ⋯ The bispectral index (BIS) value immediately before the electroconvulsive therapy (ECT) stimulus correlates with the duration of the motor and electroencephalogram (EEG) seizure activity during methohexital anesthesia. In addition, the increase in the BIS value during the ECT-induced seizure was proportional to the duration of EEG seizure activity. However, the BIS value on awakening from anesthesia varied widely, from 29 to 97.
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Anesthesia and analgesia · Jun 2003
Comparative Study Clinical TrialProne position improves lung mechanical behavior and enhances gas exchange efficiency in mechanically ventilated chronic obstructive pulmonary disease patients.
Pronation might favorably affect respiratory system (rs) mechanics and function in volume-controlled, mode-ventilated chronic obstructive pulmonary disease (COPD) patients. We studied 10 COPD patients, initially positioned supine (baseline supine [supine(BAS)]) and then randomly and consecutively changed to protocol supine (supine(PROT)), semirecumbent, and prone positions. Rs mechanics and inspiratory work (W(I)) were assessed at baseline (0.6 L) (all postures) and sigh (1.2 L) (supine(BAS) excluded) tidal volume (V(T)) with rapid airway occlusion during constant-flow inflation. Hemodynamics and gas exchange were assessed in all postures. There were no complications. Prone positioning resulted in (a) increased dynamic-static chest wall (cw) elastance (at both V(Ts)) and improved oxygenation versus supine(BAS), supine(PROT), and semirecumbent, (b) decreased additional lung (L) resistance-elastance versus supine(PROT) and semirecumbent at sigh V(T), (c) decreased L-static elastance (at both V(Ts)) and improved CO(2) elimination versus supine(BAS) and supine(PROT), and (d) improved oxygenation versus all other postures. Semirecumbent positioning increased mainly additional cw-resistance versus supine(BAS) and supine(PROT) at baseline. V(T) W(I)-sub-component changes were consistent with changes in rs, cw, and L mechanical properties. Total rs-W(I) and hemodynamics were unaffected by posture change. After pronation, five patients were repositioned supine (supine(POSTPRO)). In supine(POSTPRO), static rs-L elastance were lower, and oxygenation was still improved versus supine(BAS). Pronation of mechanically ventilated COPD patients exhibits applicability and effectiveness and improves oxygenation and sigh-L mechanics versus semirecumbent ("gold standard") positioning. ⋯ By assessing respiratory mechanics, inspiratory work, hemodynamics, and gas exchange, we showed that prone positioning of mechanically ventilated chronic obstructed pulmonary disease patients improves oxygenation and lung mechanics during sigh versus semirecumbent positioning. Furthermore, certain pronation-related benefits versus preprone-supine positioning (reduced lung elastance and improved oxygenation) are maintained in the postprone supine position.
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Anesthesia and analgesia · Jun 2003
Survival with full neurologic recovery after prolonged cardiopulmonary resuscitation with a combination of vasopressin and epinephrine in pigs.
We sought to determine the effects of a combination of vasopressin and epinephrine on neurologic recovery in comparison with epinephrine alone and saline placebo alone in an established porcine model of prolonged cardiopulmonary resuscitation (CPR). After 4 min of cardiac arrest, followed by 3 min of basic life support CPR, 17 animals were randomly assigned to receive, every 5 min, either a combination of vasopressin and epinephrine (vasopressin [IU/kg]/epinephrine [ micro g/kg]: 0.4/45, 0.4/45, and 0.8/45; n = 6), epinephrine alone (45, 45, and 200 micro g/kg; n = 6), or saline placebo alone (n = 5). After 22 min of cardiac arrest, including 18 min of CPR, defibrillation was attempted to achieve the return of spontaneous circulation. Aortic diastolic pressure was significantly (P < 0.01) increased 90 s after each of 3 vasopressin/epinephrine injections versus epinephrine alone versus saline placebo alone (mean +/- SEM: 69 +/- 3 mm Hg versus 45 +/- 3 mm Hg versus 29 +/- 2 mm Hg, 63 +/- 4 mm Hg versus 27 +/- 3 mm Hg versus 23 +/- 1 mm Hg, and 52 +/- 4 mm Hg versus 21 +/- 3 mm Hg versus 16 +/- 3 mm Hg, respectively). Spontaneous circulation was restored in six of six vasopressin/epinephrine pigs, whereas six of six epinephrine and five of five saline placebo pigs died (P < 0.01). Neurologic evaluation 24 h after successful resuscitation revealed only an unsteady gait and was normal 5 days after the experiment in all vasopressin/epinephrine-treated animals. In conclusion, in this porcine model of prolonged CPR, repeated vasopressin/epinephrine administration, but not epinephrine or saline placebo alone, ensured long-term survival with full neurologic recovery. ⋯ We present a study to evaluate the effects of a combination of vasopressin and epinephrine during prolonged cardiopulmonary resuscitation on neurological outcome in pigs. We found that all pigs treated with a combination of vasopressin and epinephrine could be resuscitated and had full neurologic recovery observed over an entire period of 5 days.
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Anesthesia and analgesia · Jun 2003
Clinical TrialThe effect of graded hypothermia (36 degrees C-32 degrees C) on hemostasis in anesthetized patients without surgical trauma.
The isolated effects of hypothermia on hemostasis have not been investigated in healthy humans. We cooled 16 anesthetized patients scheduled for elective intracranial surgery to 32 degrees C body core temperature and assessed prothrombin time (PT), activated partial thromboplastin time, thrombelastogram (TEG), closure time, and platelet count at 36 degrees C, 34 degrees C, and 32 degrees C body core temperature after the induction of anesthesia but before surgical intervention. Activated partial thromboplastin time, hematocrit, and closure time did not change, whereas PT and platelet count decreased during cooling. Platelet count decreased without a decrease in hematocrit; hence, a dilution by administered fluids seemed unlikely. The small decrease of platelet count is probably clinically irrelevant in patients with normal platelet count and function. The small decrease in PT indicates an alteration of the extrinsic pathway of coagulation. TEG measurements showed a delay of clot formation in temperature-adjusted measurements but showed no change if the test temperature was 37 degrees C. This indicates that hypothermia reduces plasmatic coagulation and platelet reactivity. However, the clot strength is not altered by hypothermia. All coagulation variables remained within the normal ranges. Our results may indicate that moderate short-term (4-h) hypothermia has only minor adverse effects in healthy humans. We can make no statement about the effects of hypothermia of longer duration. ⋯ This study investigated the isolated effects of hypothermia in healthy anesthetized humans. We found only minor effects of body temperature reduction to 32 degrees C on assessed coagulation variables, indicating only minor effects in otherwise healthy humans.