Pain management in the critically ill obstetric patient.

Safe and successful pain management in pregnant women requires an understanding of the normal physiologic changes of pregnancy. Some hemodynamic changes of labor and delivery are attenuated by effective epidural analgesia. The ideal analgesic agent for laboring parturients should produce a rapid onset of analgesia that lasts throughout labor without any adverse effect on the mother or fetus. There is no ideal analgesic for pain relief in labor. The physiologic changes of labor and delivery are reviewed, together with commonly used analgesic techniques. Special emphasis is placed on critically ill obstetric patients with concomitant cardiac disease.

Plasma concentration profile of epidural alfentanil. Bolus followed by continuous infusion technique in the parturient: effect of epidural alfentanil and fentanyl on fetal heart rate.

BACKGROUND AND OBJECTIVES: A combined bolus and continuous epidural infusion technique of opioid and bupivacaine mixture has been described, although no pharmacokinetic data for this technique exists. The study documents the plasma concentration profile of epidural alfentanil in parturients using this technique, and evaluates the fetal heart rate tracing for associated changes following opioid administration. METHODS: Twenty-four subjects were randomized to receive epidural alfentanil 500 micrograms in 10 mL 0.125% bupivacaine, group A, or fentanyl 50 micrograms in 10 mL 0.125% bupivacaine, group B, as a bolus dose, followed by continuous infusions of alfentanil 20 micrograms/mL in 0.125% bupivacaine (group A) or fentanyl 2 micrograms/mL in 0.125% bupivacaine (group B) for labor analgesia. Plasma drug levels for each group were examined using repeated measures analysis of covariance. RESULTS: Fetal heart rate tracings were recorded throughout the study and were retrospectively analyzed by a "blinded" perinatologist. Data from fetal heart rate tracings were examined by repeated measures analysis of variance. Mean infusion rates were 9.3 +/- 2.1 mL/hour and 9.6 +/- 1.7 mL/hour for groups A and B, respectively. Mean study duration was 3.7 hours in group A, and 3.0 hours in group B. Low plasma levels precluded analysis of fentanyl data. Group A subjects exhibited stability of drug levels over time. Fetal heart rate tracings in 21 patients demonstrated no changes associated with epidural opioid infusion in either group. CONCLUSIONS: With the dosage regimen used in this study, an initial epidural bolus with continuous infusion technique generates a steady state plasma concentration of alfentanil that is below levels associated with direct respiratory depression.

The addition of epinephrine to subarachnoid administered hyperbaric bupivacaine with fentanyl for cesarean delivery: the effect on onset time.

BACKGROUND AND OBJECTIVES: This study examines the effect of epinephrine on the time to achieve a T4 sensory level when added to a hyperbaric bupivacaine-fentanyl mixture for spinal anesthesia. METHODS: Sixty-nine healthy parturients scheduled for elective cesarean delivery were randomly assigned to three groups. All patients were given 9 mg hyperbaric 0.75% bupivacaine with 25 micrograms fentanyl. Group 1 received no epinephrine while Groups 2 and 3 received 100 micrograms and 200 micrograms epinephrine, respectively. Injection of the spinal anesthetic solutions was performed with the patient in the sitting position. Immediately after drug administration, patients were placed supine with their heads elevated on a pillow and 15 degrees of left uterine displacement was maintained. Vital signs and sensory levels were obtained every minute for 10 minutes. RESULTS: In Groups 2 and 3, the mean time to T4 sensory level was significantly longer (6.9 minutes and 6.6 minutes, respectively) than in Group 1 (4.6 minutes). As a subset, patients weighing more than 90.8 kg achieved a T4 sensory level faster than did those weighting less than 90.8 kg (3 minutes and 5.1 minutes, respectively), but in both groups epinephrine prolonged the onset time to T4 (5.8 minutes and 7.3 minutes, respectively). Three patients were excluded because of failure to obtain a T4 sensory level. CONCLUSIONS: The onset time to T4 is related inversely to patient weight, and epinephrine (100 micrograms and 200 micrograms) delays the onset of sensory block to T4 when administered with subarachnoid hyperbaric bupivacaine-fentanyl.

Continuous spinal blockade: an old technique revisited.

In this paper we describe a technique for continuous spinal anesthesia, first described at the turn of the 20th century and long thought to have become obsolete. We discuss reasons for discontinuance and neglect of the technique, as well as its indications, applications, and specific advantages, and we report a significant illustrative case.

Hypnoanesthesia in the morbidly obese.

The advent of chemical anesthesia relegated hypnosis to an adjunctive role in patients requiring major operations. Anesthesia can be utilized with acceptable risk in the great majority of patients encountered in modern practice. But an occasional patient will present--such as one with morbid obesity--who needs a surgical procedure and who cannot be safely managed by conventional anesthetic techniques. This report describes our experience with such a patient and illustrates some of the advantages and disadvantages of hypnoanesthesia. The greatest disadvantage is that it is unpredictable. Close cooperation between the patient, hypnotist, anesthesiologist, and surgeon is critical. However, the technique may be utilized to remove very large lesions in selected patients. Hypnoanesthesia is an important alternative for some patients who cannot and should not be managed with conventional anesthetic techniques.