Anesthesia and analgesia
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Clinical TrialThe effect of preoperative dexamethasone on the immediate and delayed postoperative morbidity in children undergoing adenotonsillectomy.
In this prospective, randomized, double-blind, placebo-controlled study, we examined the effect of preoperative dexamethasone on postoperative nausea and vomiting (PONV) and 24-h recovery in children undergoing tonsillectomy. One hundred thirty children, 2-12 yr of age, ASA physical status I or II, completed the study. All children received oral midazolam 0.5-0.6 mg/kg preoperatively. Anesthesia was induced with halothane and nitrous oxide in 60% oxygen and maintained with nitrous oxide and isoflurane. Intubation was facilitated by mivacurium 0.2 mg/kg. Each child received fentanyl 1 microgram/kg i.v. before initiation of surgery, as well as dexamethasone 1 mg/kg (maximal dose 25 mg) (steroid group) or an equal volume of saline (control group). Intraoperative fluids were standardized to 25-30 mL/kg lactated Ringer's solution. All tonsillectomies were performed under the supervision of one attending surgeon using an electrodissection technique. Postoperatively, fentanyl and acetaminophen with codeine elixir were administered as needed for pain. Rescue antiemetics were administered when a child experienced two episodes of retching and/or vomiting. Before home discharge, the incidence of PONV, need for rescue antiemetics, quality or oral intake, and analgesic requirements did not differ between groups. However, during the 24 h after discharge, more patients in the control group experienced PONV (62% vs 24% in the steroid group) and complained of poor oral intake. Additionally, more children in the control group (8% vs 0% in the steroid group) returned to the hospital for the management of PONV and/or poor oral intake. The preoperative administration of dexamethasone significantly decreased the incidence of PONV over the 24 h after home discharge in these children. ⋯ In this double blind, placebo-controlled study, we examined the efficacy of a single large dose (1 mg/kg; maximal dose 25 mg) of preoperative dexamethasone on posttonsillectomy postoperative nausea and vomiting (PONV) in children 2-12 yr of age undergoing tonsillectomy. Compared with placebo, dexamethasone significantly decreased the incidence of PONV in the 24 h after discharge, improved oral intake, decreased the frequency of parental phone calls, and resulted in no hospital returns for the management of PONV and/or poor oral intake.
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Clinical TrialThe effect of clonidine or midazolam premedication on perioperative responses during ketamine anesthesia.
The use of ketamine as a sole anesthetic induces marked central sympathetic stimulation, causing increased heart rate, blood pressure (BP), and oxygen consumption (VO2). Both alpha 2-agonists and benzodiazepines have been used to attenuate these potentially harmful ketamine-induced responses. This double-blind, randomized, placebo-controlled study was designed to compare the perioperative metabolic, hemodynamic, and sympathoadrenal responses to IM clonidine (2 micrograms/kg) and midazolam (70 micrograms/kg) premedication during ketamine anesthesia. VO2 was measured continuously using indirect calorimetry in 30 ASA physical status I patients. The patients received ketamine, mivacurium, and fentanyl for the induction of anesthesia. Anesthesia was maintained using a ketamine infusion and fentanyl boluses i.v. Preoperatively, both VO2 and BP decreased significantly after the administration clonidine and midazolam compared with placebo (P < 0.01). Intraoperatively, VO2 was higher in the midazolam group than in the placebo and clonidine groups (P < 0.05). Postoperatively, there were no significant differences in BP and VO2, although they stayed at lower level in the clonidine group during the whole postoperative period. Clonidine decreased pre- and postoperative plasma catecholamine concentrations (P < 0.05). Our results indicate that a midazolam-ketamine combination may induce potentially harmful metabolic stimulation, whereas the sympatholytic effects of clonidine on ketamine-anesthetized patients may be beneficial, as perioperative VO2 was decreased. ⋯ Ketamine causes sympathetic stimulation with an ensuing increase in oxygen consumption. Anticipating that clonidine might attenuate this response, we measured oxygen consumption in patients undergoing surgery during ketamine anesthesia. Patients treated with a clonidine-ketamine combination had lower intra- and postoperative oxygen consumption than those treated with a midazolam-ketamine combination.
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Clinical TrialDose-response of ketorolac as an adjunct to patient-controlled analgesia morphine in patients after spinal fusion surgery.
This randomized, blind study was designed to determine the appropriate dose of ketorolac (a drug used as a supplement to opioids) to administer to patients who have undergone spinal stabilization surgery. The ketorolac was administered every 6 h, in addition to patient-controlled analgesia (PCA) with morphine, to 70 inpatients undergoing spine stabilization by one surgeon. The study was performed to determine the analgesic efficacy and incidence of side effects with different doses of ketorolac. The patients were divided into seven groups. They were given either i.v. saline (control group) or i.v. ketorolac (5, 7.5, 10, 12.5, 15, or 30 mg) every 6 h. The outcomes measured included pain scores, 24-h morphine usage, level of sedation, and side effect profile six times during the first 24 h postoperatively. The total dose of morphine was significantly larger in the control and 5 mg ketorolac groups than in the other five groups. Morphine consumption was similar in all groups receiving > or = 7.5 mg of ketorolac. The pain scores were significantly higher in the control group than in some of the larger dose groups at three of the study intervals. The 5 mg group had higher pain scores than the other groups at most of the time intervals studied. There were no significant differences in pain scores among the other five groups. Sedation scores were higher (i.e., patients were more sedated) in the control group than in the other six groups at three of the time periods. We conclude that the administration of ketorolac 7.5 mg every 6 h has a morphine-sparing effect equivalent to that of larger doses in patients undergoing spine stabilization surgery. Using larger doses of ketorolac did not result in less somnolence, lower morphine use, or less pain. We recommend that ketorolac 7.5 mg be given every 6 h to patients undergoing spinal fusion surgery in addition to PCA morphine. ⋯ Using smaller doses of ketorolac (e.g., 7.5 mg every 6 h) as a supplement to morphine patient-controlled analgesia is as effective as larger doses in patients who have undergone spine stabilization surgery.
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Comparative Study Clinical TrialThe placement of the cuffed oropharyngeal airway with sevoflurane in adults: a comparison with the laryngeal mask airway.
We sought to determine the anesthetic duration of sevoflurane required to achieve good conditions for placement of a cuffed oropharyngeal airway (COPA) or a laryngeal mask airway (LMA). Forty adult ASA physical status I or II patients presenting for elective surgery received single-breath vital capacity inhaled induction with 5% sevoflurane via face mask; thereafter, ventilation was manually assisted. The patients were randomized to receive either a COPA or LMA placement. The time of anesthetic exposure was varied for consecutive patients using the staircase method. The mean (95% confidence interval) anesthetic time required for acceptable COPA placement (100 [55-145] s) was significantly shorter than that for LMA (160 [101-219] s). The 50% and 95% effective doses (from logistic analyses) for acceptable conditions associated with COPA or LMA placement were 90 s and 145 s or 164 s and 261 s, respectively. These findings suggest that COPA insertion is less stimulating than the LMA. ⋯ The cuffed oropharyngeal airway is a new airway device that is similar to a laryngeal mask airway in many ways. However, it requires shorter anesthetic duration for successful placement, which suggests that it can be placed with less stimulation. It may be an alternative to a laryngeal mask airway.
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Anesthesia and analgesia · Jul 1998
Randomized Controlled Trial Clinical TrialWarming intravenous fluids reduces perioperative hypothermia in women undergoing ambulatory gynecological surgery.
We evaluated whether warming i.v. fluids resulted in less hypothermia (core temperature < 35.5 degrees C) compared with room-temperature fluids. Thirty-eight adult outpatients undergoing elective gynecological surgery of > 30 min were randomized to two groups: fluid warming at 42 degrees C or control (room temperature fluids at approximately 21 degrees C). All patients received general anesthesia with isoflurane, tracheal intubation, standard operating room blankets and surgical drapes, and passive humidification of inspired gases. Tympanic membrane (core) temperatures were measured at baseline and at 15-min intervals after induction. The incidence of shivering and postoperative requirement for meperidine and/or radiant heat were evaluated. Core temperatures were lower in the control compared with the warm fluid group at the end of surgery (35.6 +/- 0.1 degrees C vs 36.2 +/- 0.1 degrees C; P < 0.05). More patients had final core temperature < 35.5 degrees C in the control compared with the warm fluid group (35% vs 0%; P < 0.05). There were no differences in time to discharge from the postanesthesia care unit or the incidence of shivering between the groups. We conclude that fluid warming, in conjunction with standard heat conservation measures, was effective in maintaining normothermia during outpatient gynecological surgery; however, there was no improvement in patient outcome. ⋯ Women who received i.v. fluid at body temperature had significantly higher core temperatures during and after outpatient gynecological surgery compared with women who received i.v. fluids at the temperature of the operating room.