Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2002
Randomized Controlled Trial Comparative Study Clinical TrialPostoperative nausea and vomiting in children and adolescents undergoing radiofrequency catheter ablation: a randomized comparison of propofol- and isoflurane-based anesthetics.
In children, radiofrequency catheter ablation (RFCA) is typically performed under general anesthesia. With the use of volatile anesthetics, postoperative nausea and vomiting (PONV) are common, with an incidence of emesis as frequent as 60%. We tested the hypothesis that a propofol (PRO)-based anesthetic would have a less frequent incidence of PONV than an isoflurane (ISO)-based anesthetic. Patients were randomly assigned to receive either an ISO- or PRO-based anesthetic. Prophylactic ondansetron was given to all patients and droperidol was used as a rescue antiemetic postoperatively while PONV was monitored postoperatively for 18 h. The incidence of nausea, vomiting, use of rescue antiemetic drugs, and sedation scores were recorded. The cost for the anesthetic was also calculated. Fifty-six subjects were included in this study. The cumulative incidence of PONV was significantly more frequent in group ISO (63% nausea/55% emesis) compared with group PRO (21% nausea/6% emesis). After the administration of droperidol, further vomiting occurred in 70% of the patients in group ISO versus 0% of the patients in group PRO. We conclude that RFCA using ISO has a high PONV risk and the prophylactic use of ondansetron as well as antiemetic therapy with droperidol are ineffective. In contrast, a PRO-based anesthetic is highly effective in preventing PONV in children undergoing RFCA. ⋯ In children undergoing radiofrequency catheter ablation and receiving prophylactic ondansetron, a frequent incidence (60%) of postoperative vomiting was observed under an isoflurane-based anesthetic, whereas the incidence was significantly reduced to a very low level (5%) under a propofol-based anesthetic.
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Anesthesia and analgesia · Dec 2002
Randomized Controlled Trial Clinical TrialSinusoidal neck suction for evaluation of baroreflex sensitivity during desflurane and sevoflurane anesthesia.
Sevoflurane and desflurane modulate autonomic nervous activity by different mechanisms. We tested the hypothesis that these anesthetics also exhibit different effects on short-term baroreflex regulation of arterial blood pressure. Forty ASA physical status I patients, aged 20 to 42 yr, were randomly assigned to receive either 1.0 minimum alveolar anesthetic concentration of sevoflurane or desflurane for the maintenance of anesthesia. Patients were studied during awake conditions and 20 min after the anesthesia induction using sinusoidal neck suction at 0.2 Hz (baroreflex response mediated mainly by vagal activity) and 0.1 Hz (baroreflex response mediated by vagal and sympathetic activity), whereas respiratory frequency was fixed at 0.25 Hz. RR interval and arterial blood pressure responses were evaluated by power spectral analysis and complex transfer function analysis. Sevoflurane and desflurane did not disturb the linear relationship between baroreceptor stimulation and effector response, expressed as squared coherence of signals, i.e., the equivalent of the correlation coefficient of power spectra. Sevoflurane and desflurane depressed the response of the heart rate to neck suction in a similar way without affecting the time delay between baroreceptor stimulation and vagal-mediated cardiac response. The gain of the transfer function between neck suction and oscillation in arterial blood pressure at 0.1 Hz decreased with sevoflurane and desflurane to comparable values. Both anesthetics increased the delay of systolic blood pressure response to baroreceptor stimulation from approximately 3.5 to 4.3 s. Baroreflex-mediated short-term control of arterial blood pressure is similar between desflurane and sevoflurane during steady-state conditions. ⋯ Despite exhibiting different effects on autonomic activity, sevoflurane and desflurane depress the baroreflex-mediated short-term control of heart rate and blood pressure in a similar manner.
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Anesthesia and analgesia · Dec 2002
Comparative StudyThe relationship between movement-evoked versus spontaneous pain and peak expiratory flow after abdominal hysterectomy.
The pathogenesis of postoperative lung dysfunction implies a role for movement-evoked pain (e.g., splinting/hypoventilation because of pain avoidance). However, interactions between evoked pain and respiratory physiology are poorly understood. Thus, we examined the relationship between evoked versus spontaneous pain and one index of pulmonary function. In 25 patients having undergone a hysterectomy, visual analog scale ratings (100 mm) for spontaneous pain (REST) and pain during sitting (SIT), forced expiration (BLOW), and coughing (COUGH) were measured together with peak expiratory flow (PEF) at eight time points during postoperative Days 1 and 2. Secondary outcome measures included oxygen saturation and oxygen requirements. Pain was significantly correlated with PEF for COUGH, SIT, BLOW, and REST at eight, seven, four, and two of the eight studied time points, respectively. Mean visual analog scale scores [SE] for COUGH (26.1 mm [1.7]) and SIT (21.5 mm [1.5]) were greater (P < 0.05) than REST (10.5 mm [0.8]), and COUGH was greater (P < 0.05) than BLOW (16.8 mm [1.3]). All pain measures diminished (P < 0.05), and PEF reductions improved (P < 0.05) across the study period. We hypothesize that the consistent negative correlation of COUGH-evoked pain with PEF is, in part, caused by avoidance of coughing, which ultimately limits deep inspiration, lung reexpansion, and clearance of secretions. ⋯ Movement-evoked pain may be an important contributor to postoperative complications, but its mechanisms are poorly understood. This study provides the first evidence that postoperative evoked pain correlates with lung function and highlights the need for future research on mechanisms and implications of this phenomenon.
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Anesthesia and analgesia · Dec 2002
Initial experience with a novel heat-exchanging catheter in neurosurgical patients.
Even mild hypothermia provides marked protection against cerebral ischemia in animal models. Hypothermia may be of therapeutic value during neurosurgical procedures. However, current cooling systems often fail to induce sufficient hypothermia before the dura is opened. Furthermore, they usually fail to restore normothermia by the end of surgery, thus delaying extubation. We evaluated a new internal heat-exchanging catheter. Eight ASA physical status II-IV patients (29-72 yr) undergoing craniotomy were enrolled. After the induction of general anesthesia, we introduced the SetPoint catheter into the inferior vena cava via a femoral vein. The target core body temperature was 34 degrees C-34.5 degrees C. After reaching the target, core temperature was maintained until the dura was closed. Target core temperature was then set to 37.0 degrees C, and the patient was rewarmed as quickly as possible. Seven patients had a tumor resection, and one had an aneurysm clipped. The core-cooling rate was 3.9 degrees C +/- 1.6 degrees C/h, and the rewarming rate was 2.0 degrees C +/- 0.5 degrees C/h; core temperature was 35.9 degrees C +/- 0.2 degrees C by the end of surgery. Patients were subsequently kept normothermic for 3 h before the catheter was removed. No thrombus or other particulate material was identified on the extracted catheters. None of the patients suffered any complications that could be attributed to the SetPoint system or thermal management. ⋯ Because current systems for inducing therapeutic hypothermia are too slow, we tested an internal counter-current thermal management system during hypothermic neurosurgery. The SetPoint catheter cooled at 3.9 degrees C +/- 1.6 degrees C/h and rewarmed at 2.0 degrees C +/- 0.5 degrees C/h. Catheter-based internal thermal management thus seems to be rapid and effective.
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Anesthesia and analgesia · Dec 2002
Precardiopulmonary bypass right ventricular function is associated with poor outcome after coronary artery bypass grafting in patients with severe left ventricular systolic dysfunction.
Patients with severe left ventricular systolic dysfunction (LVSD) undergoing coronary artery bypass grafting (CABG) have an increased risk for morbidity and mortality. The purpose of this study was to assess the association of pre-CABG right ventricular (RV) function with outcome for patients with severe LVSD. We performed a retrospective evaluation of 41 patients with severe LVSD (left ventricular ejection fraction [LVEF] < or =25%) scheduled for nonemergent CABG. Data were obtained from review of medical records, transesophageal echocardiography tapes, and phone interview. The pre- and post-cardiopulmonary bypass (CPB) LVEF and the RV fractional area of contraction (RVFAC) were calculated by using intraoperative transesophageal echocardiography. Group 1 patients had an RVFAC < or =35% (n = 7), whereas Group 2 patients had RVFAC >35% (n = 34). The durations of mechanical ventilation and of intensive care unit and hospital stays are presented as the median. Pre-CABG LVEF was similar between Groups 1 and 2 (15.8% +/- 3.3% versus 17.8% +/- 3.9%). Compared with Group 2, Group 1 patients required greater duration of mechanical ventilation (12 days versus 1 day; P < 0.01), longer intensive care unit (14 versus 2 days; P < 0.01) and hospital (14 versus 7 days; P = 0.02) stays, had a more frequent incidence and severity of LV diastolic dysfunction, and had a smaller change in LVEF immediately after CPB (4.1% +/- 8.3% versus 12.5% +/- 9.2%; P = 0.03). All Group 1 patients died of cardiac causes within 2 yr of surgery; five died during the same hospital admission. Three Group 2 patients died: one of colon cancer at 18 mo after CABG and two of cardiac causes 24 and 48 mo after surgery. A fourth patient was awaiting cardiac transplantation 4 yr after surgery. The remaining Group 2 patients were New York Heart Association Classification I or II. For patients with severe LVSD undergoing CABG, pre-CPB RV dysfunction was associated with poor outcome. Patients with RVFAC >35% had a relatively uneventful perioperative course and good long-term survival, whereas patients with RVFAC < or =35% had a poor early and late outcome. Assessment of RV function is useful to further assess the risk of CABG. ⋯ Right ventricular function before cardiopulmonary bypass is associated with poor outcome after coronary artery surgery in patients with poor left ventricular function.