Anesthesia and analgesia
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Anesthesia and analgesia · Jun 1998
Randomized Controlled Trial Comparative Study Clinical TrialPropofol versus midazolam: safety and efficacy for sedating the severe trauma patient.
Previous studies have compared sedation profiles with midazolam (Mz) and propofol (Pf), particularly in heterogeneous populations of patients. Decreases in blood pressure and heart rate have been reported after the administration of propofol. These side effects are potentially deleterious in severe trauma patients, particularly in patients with head trauma. To assess the safety and efficacy of Mz and Pf, alone or in combination, in the prolonged sedation of severe trauma patients, we designed a prospective, controlled, randomized, study. One hundred consecutively admitted trauma patients requiring mechanical ventilation and sedation for more than 48 h were studied. Patients were sedated according to three different protocols based on the continuous i.v. administration of Mz alone, Pf alone, and Mz in combination with Pf. All patients received morphine chloride. Safety and efficacy were assessed during the sedation and wake-up periods according to clinical and laboratory variables. Cerebral hemodynamics were also studied in patients with head trauma. Patients were sedated for 6.3 +/- 4.0 days (mean +/- SD). All three sedation regimens were equally efficacious in achieving the desired sedation goal. The incidence of adverse events during the sedation period was also similar. In head trauma patients with intracranial pressure (ICP) monitoring, we did not find differences in ICP, cerebral perfusion pressure, or jugular venous oxygen saturation among the three groups. The serum triglyceride concentration was significantly higher in the Pf group. Wake-up time was significantly shorter in the Pf group. We conclude that both Mz and Pf are safe and efficacious in the sedation of severe trauma patients. The use of Pf in these patients is associated with a high incidence of hypertriglyceridemia and a shorter wake-up time. ⋯ In a prospective, controlled, randomized study, we confirmed the safety and efficacy of midazolam and propofol, alone or in combination, in the prolonged sedation of a homogeneous group of severe trauma patients, particularly in patients with head trauma. The propofol group had shorter wake-up times and higher triglyceride levels.
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Anesthesia and analgesia · Jun 1998
Randomized Controlled Trial Clinical TrialAdding ketamine in a multimodal patient-controlled epidural regimen reduces postoperative pain and analgesic consumption.
We designed this double-blind study to evaluate the effect of adding small-dose ketamine in a multimodal regimen of postoperative patient-controlled epidural analgesia (PCEA). Ninety-one patients, ASA physical status I-III, undergoing major surgery, received a standardized general anesthesia and epidural catheterization in an appropriate intervertebral space after surgery. A PCEA device was programmed to deliver a regimen of morphine 0.02 mg/mL, bupivacaine 0.8 mg/mL, and epinephrine 4 microg/mL, with the addition of ketamine 0.4 mg/mL (ketamine, n = 45) or without (control, n = 46). The mean visual analog pain scale (VAS) scores during cough or movement for the first 3 days after surgery were higher in the control group than in the ketamine group (P < 0.05), whereas the mean VAS score at rest for the first 2 days were higher in the control group than in the ketamine group (P < 0.05). Furthermore, patients in the control group consumed more multimodal analgesics than patients in the ketamine group for the first 2 days (P < 0.05). The sedation scores and the incidence of side effects (pruritus, nausea, emesis, sleep deprivation, motor block, and respiration depression) were similar between the two groups. We conclude that adding ketamine 0.4 mg/mL in a multimodal PCEA regimen provides better postoperative pain relief and decreases consumption of analgesics. ⋯ Many studies have evaluated one or a combination of two analgesics for postoperative pain control, but few have examined a multimodal approach using three or four different epidural analgesics. This study demonstrates an additive analgesic effect when ketamine is added to a multimodal analgesic treatment.
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Anesthesia and analgesia · Jun 1998
Randomized Controlled Trial Comparative Study Clinical TrialArterial oxygenation and shunt fraction during one-lung ventilation: a comparison of isoflurane and sevoflurane.
The aim of this study was to evaluate the effect of isoflurane and sevoflurane on oxygenation and shunt fraction during one-lung ventilation (OLV). Twenty patients undergoing lobectomy for lung cancer and scheduled for long-term OLV were enrolled in this study. Patients were allocated to treatment with either isoflurane or sevoflurane. Arterial oxygenation, shunt fraction, and hemodynamics were evaluated at the end of two-lung ventilation; 20 min after the initiation of OLV; 20 min after the application of 4-cm positive end-expiratory pressure (PEEP) to the dependent lung; 20 min after 8-cm PEEP; and 20 min after the conversion from OLV to two-lung ventilation. There was no significant difference between isoflurane and sevoflurane with regard to oxygenation, shunt fraction, or hemodynamics during OLV. PaO2 values after the application of 4-cm PEEP increased from 131.1 +/- 11.8 mm Hg to 190.6 +/- 22.9 mm Hg in the isoflurane group (P < 0.05) and from 127.2 +/- 14.3 mm Hg to 192.4 +/- 26.9 mm Hg in the sevoflurane group (P < 0.05). The selection of either isoflurane or sevoflurane for OLV was made without regard to arterial oxygenation and shunt fraction. PEEP application to the dependent lung is useful for improving oxygenation during OLV, but 8-cm PEEP had no added effect compared with 4-cm PEEP. ⋯ We compared the effects of isoflurane and sevoflurane on oxygenation, hemodynamics, and shunt fraction during one-lung ventilation in 20 patients undergoing scheduled lobectomy for lung cancer. There was no significant difference between isoflurane and sevoflurane with regard to oxygenation, shunt fraction, and hemodynamics during one-lung ventilation. The application of 4-cm positive end-expiratory pressure increased the partial pressure of arterial oxygen during one-lung ventilation.
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Anesthesia and analgesia · Jun 1998
Randomized Controlled Trial Clinical TrialExperimental pain in healthy human subjects: gender differences in nociception and in response to ibuprofen.
We used electrically induced pain in healthy young subjects to study gender differences in nociception and the analgesic efficacy of ibuprofen. Cutaneous stimulation of the earlobe allowed measurement of pain detection thresholds and maximal pain tolerance. Drug and placebo were each administered twice using a double-blind, randomized, multiple cross-over design. Male subjects had greater stimulus thresholds (lower nociception) compared with female subjects (18 +/- 0.3 vs 15 +/- 0.3 volts, mean +/- SEM; n = 10 in each group) and a greater pain tolerance (24 +/- 0.4 vs 21 +/- 0.4 volts). Response variability was also greater in the male subjects, yet only the men exhibited a statistically significant analgesic response to ibuprofen (deltavolts; ibuprofen versus placebo: 2.80 +/- 0.33 vs -0.18 +/- 0.34; P < 0.05, n = 10). None of these results could be attributed to pharmacokinetic differences. The finding that ibuprofen was less effective in women than in men has potential clinical significance, especially as a factor in the response variability to nonsteroidal antiinflammatory drugs. ⋯ In this study, we examined ibuprofen, a widely used nonsteroidal antiinflammatory drug, for its ability to reduce experimental pain. We found that it had such properties in healthy young male subjects but not in young female subjects. This is a paradox because many of the painful conditions for which nonsteroidal antiinflammatory drugs are used (e.g., rheumatoid arthritis) occur more often in women.
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Anesthesia and analgesia · Jun 1998
Randomized Controlled Trial Clinical TrialThe combination of epinephrine and isoproterenol as a simulated epidural test dose in isoflurane-anesthetized adults.
During isoflurane anesthesia, an epinephrine-containing test dose produces unreliable heart rate (HR) responses with a high incidence of hypertension, whereas an isoproterenol-containing test dose results in a high incidence of hypotension. We designed this study to determine whether different combination doses of epinephrine and isoproterenol produce reliable HR changes without overt fluctuations of systolic blood pressure (SBP). Seventy-five healthy patients were anesthetized with 1% end-tidal isoflurane after endotracheal intubation and randomized to one of five groups (n = 15 each) according to the combination dose given i.v.: epinephrine 15 microg, epinephrine 15 microg + isoproterenol 1.5 microg, epinephrine 7.5 microg + isoproterenol 3 microg, isoproterenol 3 microg, and saline. HR and SBP were measured at 20-s intervals for 4 min after injection. Based on the conventional HR criterion (positive if > or = 20 bpm increase), the epinephrine 15 microg + isoproterenol 1.5 microg, the epinephrine 7.5 microg + isoproterenol 3 microg, and the isoproterenol 3 microg groups yielded 100% sensitivities, specificities, and positive and negative predictive values, whereas all groups yielded 100% efficacy according to the modified HR criterion (positive if > or = 10 bpm increase). Four (27%) and three patients (20%) in the epinephrine 15 microg and the epinephrine 15 microg + isoproterenol 1.5 microg groups, respectively, developed systolic hypertension (SBP > or = 180 mm Hg), whereas four (27%) patients in the isoproterenol 3 microg group developed systolic hypotension (SBP < or = 80% of the preinjection value). We conclude that epinephrine 7.5 microg + isoproterenol 3 microg provides the most reliable HR changes with the least SBP fluctuations. ⋯ To test whether an epidural catheter may be in a blood vessel, various vasoactive drugs are administered during general anesthesia. The authors found that the combination of epinephrine 7.5 microg and isoproterenol 3 microg produced the most reliable heart rate changes with minimal blood pressure fluctuations.