Anesthesia and analgesia
-
Anesthesia and analgesia · Nov 1992
Comparative StudyVenous air embolism in prone dogs positioned with the abdomen hanging freely: percentage of gas retrieved and success rate of resuscitation.
Based on reports of fatal venous air embolism (VAE) occurring during lumbar laminectomy and spinal fusion in prone patients positioned with the abdomen hanging freely, it has been recommended that monitoring for VAE should be used for such cases and that a multiorificed central venous catheter should be inserted for aspiration of VAE. The present study was designed to examine aspiration of VAE when prone dogs positioned with the abdomen hanging freely were given a fatal VAE via a femoral vein. Twenty-one dogs were anesthetized with halothane and nitrous oxide in oxygen and positioned with the abdomen ventral and hanging freely, the head fixed in a stereotaxic frame, the upper extremities resting on a surface approximately 10 cm below the level of the stereotaxic frame, and the lower extremities on a surface below the level of the upper extremities (to ensure that VAE entering the inferior vena cava would ascend toward the heart). ⋯ Dogs were then given a predetermined lethal dose of air (5 mL/kg) over 30 s via the femoral vein. In groups 2 and 3, attempts to aspirate VAE were begun with the first decrease in expired CO2. The amounts of gas retrieved (expressed as a percent of the injected air) and the incidence of successful resuscitation were compared.(ABSTRACT TRUNCATED AT 250 WORDS)
-
Anesthesia and analgesia · Nov 1992
Randomized Controlled Trial Comparative Study Clinical TrialNalbuphine is better than naloxone for treatment of side effects after epidural morphine.
This study compared naloxone and nalbuphine when administered for treatment of side effects after epidural morphine, 5 mg, given for postcesarean analgesia. Patients requesting treatment for pruritus or nausea randomly received, in a double-blind fashion, up to three intravenous doses of either naloxone 0.2 mg (group 1; n = 20) or nalbuphine 5 mg (group 2; n = 20). The incidence of vomiting, the severity of nausea and pruritus, and the degree of sedation and pain were assessed before and 30 min after each dose. ⋯ Other than decreased pruritus after the second dose with both drugs, no further changes occurred. We conclude that nalbuphine is superior to naloxone for the treatment of side effects after epidural morphine. However, persistent symptoms may require supplemental therapy, as repeated doses proved less effective than the initial dose.
-
Anesthesia and analgesia · Nov 1992
Randomized Controlled Trial Clinical TrialAdverse effects of epidural 0.03% bupivacaine during analgesia after cesarean section.
To develop a regimen that would provide good analgesia after cesarean section with minimal side effects in the setting of prolonged (> 24 h) epidural infusion, buprenorphine or fentanyl was combined with 0.03% bupivacaine in a double-blind study of 23 parturients. Patients were randomly assigned to two groups: group I (n = 12), patient-controlled analgesia by epidural infusion of buprenorphine (3 micrograms/mL) with 0.03% bupivacaine; group II (n = 11), patient-controlled analgesia by epidural infusion of fentanyl (2 micrograms/mL) with 0.03% bupivacaine. Plasma for determination of opioid concentrations was obtained at intermittent intervals. ⋯ One patient in each group developed extensive pressure blisters on both heels. These complications led us to terminate the study. We conclude that 0.03% bupivacaine used in combination with an opioid in prolonged epidural infusions produces a high incidence of sensory loss in the lower extremities and is unsuitable for situations in which early ambulation is desired.
-
Anesthesia and analgesia · Nov 1992
Comparative StudyTotal intravenous anesthesia: effects of opioid versus hypnotic supplementation on autonomic responses and recovery.
During radical prostatectomy procedures under total intravenous anesthesia, acute hemodynamic responses to retropubic dissection (30% +/- 8% to 36% +/- 12% [mean +/- SD] increases in mean arterial pressure) were treated with supplemental doses of either an opioid analgesic (alfentanil) or a sedative-hypnotic (propofol) to return the mean arterial pressure to within 10% of the preincision value. Although both drugs were effective, control with propofol required 10.1 +/- 2.5 min compared with 6.3 +/- 2.6 min in the alfentanil group (mean +/- SD; P < 0.01). Plasma stress hormone concentrations increased significantly in response to this surgical stimulus: epinephrine increased from 246% +/- 169% to 283% +/- 330%; norepinephrine increased from 44% +/- 33% to 83% +/- 104%; and antidiuretic hormone increased from 1300% +/- 1591% to 1700% +/- 1328%. ⋯ In addition, 36% of the alfentanil-treated patients required antihypertensive therapy in the postanesthesia care unit compared with only 9% in the propofol group (P < 0.05). Postanesthesia care unit and hospital discharge times were similar in both treatment groups. We conclude that supplemental doses of alfentanil or propofol were equally effective in controlling acute hemodynamic and hormonal responses to surgical stimuli during total intravenous anesthesia.
-
Anesthesia and analgesia · Nov 1992
Effects of sodium L-lactate and sodium racemic lactate on intraoperative acid-base status.
Lactated Ringer's solution is frequently used to avoid metabolic acidosis during fluid resuscitation. The standard lactated Ringer's solution contains racemic lactate, an equal mixture of the D- and L-stereoisomers. We investigated whether sodium L-lactate or sodium racemic lactate (DL-lactate) is more effective for increasing buffering capacity in body fluids. ⋯ Although differences occurred among the three groups in blood concentrations of L-lactate, D-lactate, and the L-lactate/pyruvate ratio, no differences occurred between the two lactate groups in either bicarbonate ion concentration or base excess. The amount of buffering capacity increased significantly in both lactate groups, compared with preinfusion levels, and was more than the values in the nonlactated Ringer's solution group. We conclude that sodium racemic lactate is metabolized at nearly the same rate as that of sodium L-lactate.