Sheila E. Cohen

Prevention of Hypotension After Spinal Anesthesia for Cesarean Section: Six Percent Hetastarch Versus Lactated Ringer's Solution

This study was designed to determine whether preoperative administration of 6% hetastarch decreases the incidence and severity of hypotension after spinal anesthesia for cesarean section.Forty nonlaboring ASA class I and II women having nonurgent cesarean sections were randomized to receive either 500 mL of 6% hetastarch plus 1 L lactated Ringers solution (LR) (n = 20), or 2 L of LR (n = 20) prior to induction of spinal anesthesia. Hypotension occurred in 45% of patients who received hetastarch vs 85% of those who received only LR (P < 0.05), and minimum systolic blood pressure was lower in the LR group than in the hetastarch group (85 +/- 12 vs 93 +/- 12 mm Hg [mean +/- SD]; P < 0.05). In addition, the LR group had a higher maximum heart rate (115 +/- 17 vs 104 +/- 16 bpm), a shorter mean time to hypotension (7 +/- 4 vs 10 +/- 7 min), and required more 5-mg doses of ephedrine for treatment of hypotension (0 vs 2 [median]; P < 0.05) than the hetastarch group. Neonatal outcome, as determined by Apgar scores and cord blood gas analyses, was good and similar in both groups. We conclude that 6% hetastarch plus LR is more effective than LR alone and that its routine use before spinal anesthesia for cesarean section should be considered. (Anesth Analg 1995;81:838-42)

Intrathecal sufentanil for labor analgesia--sensory changes, side effects, and fetal heart rate changes.

This study was designed to evaluate intrathecal (IT) sufentanil for labor analgesia with respect to sensory changes, side effects, and fetal heart rate (FHR) changes. In Phase I of the study, data regarding duration of analgesia and hemodynamic changes were obtained retrospectively from the labor and anesthetic records of 90 patients who had received IT sufentanil, 10 micrograms in 1 mL of saline, during active labor. In Phase II, an additional 18 parturients who received similar treatment were studied prospectively to document sensory, motor, and hemodynamic changes, as well as the incidence of side effects. In Phase I, analgesia occurred rapidly and lasted 124 +/- 68 min (SD); 19% of patients required no further analgesia before delivery. In Phase II, median time to onset of analgesia was 3 min (range 1-6 min) and mean duration of analgesia was 96 +/- 36 min. Decreased sensation to pinprick and cold occurred within 6 min extending from T4 to L4 (upper and lower median levels) in the majority of patients. All subjects requested additional analgesia within approximately 30 min of recession of sensory changes. Motor strength remained normal throughout. Hypotension (systolic blood pressure [BP] < or = 90 mm Hg or > 20% decrease in systolic BP) occurred in 14% and 11% of patients in Phase I and II, respectively. Perineal itching preceded analgesia in 95% of patients and all subjects experienced mild sedation. FHR changes occurred in 15% of cases but were not associated with adverse neonatal outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Phenylephrine Added to Prophylactic Ephedrine Infusion during Spinal Anesthesia for Elective Cesarean Section

BackgroundBecause ephedrine infusion (2 mg/min) does not adequately prevent spinal hypotension during cesarean delivery, the authors investigated whether adding phenylephrine would improve its efficacy. MethodsThirty-nine parturients with American Society of Anesthesiologists physical status I–II who were scheduled for cesarean delivery received a crystalloid preload of 15 ml/kg. Spinal anesthesia was performed using 11 mg hyperbaric bupivacaine, 2.5 &mgr;g sufentanil, and 0.1 mg morphine. Maternal heart rate and systolic blood pressure were measured at frequent intervals. A vasopressor infusion was started immediately after spinal injection of either 2 mg/min ephedrine plus 10 &mgr;g/min phenylephrine or 2 mg/min ephedrine alone. Treatments were assigned randomly in a double-blind fashion. The infusion rate was adjusted according to systolic blood pressure using a predefined algorithm. Hypotension, defined as systolic blood pressure less than 100 mmHg and less than 80% of baseline, was treated with 6 mg ephedrine bolus doses. ResultsHypotension occurred less frequently in the ephedrine–phenylephrine group than in the ephedrine-alone group: 37%versus 75% (P = 0.02). Ephedrine (36 ±16 mg, mean ± SD) plus 178 ±81 &mgr;g phenylephrine was infused in former group, whereas 54 ±18 mg ephedrine was infused in the latter. Median supplemental ephedrine requirements and nausea scores (0–3) were less in the ephedrine–phenylephrine group (0 vs. 12 mg, P = 0.02; and 0 vs. 1.5, P = 0.01, respectively). Umbilical artery p H values were significantly higher in the ephedrine–phenylephrine group than in the group that received ephedrine alone (7.24 vs. 7.19). Apgar scores were similarly good in both groups. ConclusionPhenylephrine added to an infusion of ephedrine halved the incidence of hypotension and increased umbilical cord p H.

Spinal versus epidural anesthesia for cesarean section : a comparison of time efficiency, costs, charges, and complications

Spinal anesthesia recently has gained popularity for elective cesarean section.Our anesthesia service changed from epidural to spinal anesthesia for elective cesarean section in 1991. To evaluate the significance of this change in terms of time management, costs, charges, and complication rates, we retrospectively reviewed the charts of patients who had received epidural (n = 47) or spinal (n = 47) anesthesia for nonemergent cesarean section. Patients who received epidural anesthesia had significantly longer total operating room (OR) times than those who received spinal anesthesia (101 +/- 20 vs 83 +/- 16 min, [mean +/- SD] P < 0.001); this was caused by longer times spent in the OR until surgical incision (46 +/- 11 vs 29 +/- 6 min, P < 0.001). Length of time spent in the postanesthesia recovery unit was similar in both groups. Supplemental intraoperative intravenous (IV) analgesics and anxiolytics were required more often in the epidural group (38%) than in the spinal group (17%) (P < 0.05). Complications were noted in six patients with epidural anesthesia and none with spinal anesthesia (P < 0.05). Average per-patient charges were more for the epidural group than for the spinal group. Although direct cost differences between the groups were negligible, there were more substantial indirect costs differences. We conclude that spinal block may provide better and more cost effective anesthesia for uncomplicated, elective cesarean sections. (Anesth Analg 1995;80:709-12)

Placental Transfer and Neonatal Effects of Epidural Sufentanil and Fentanyl Administered with Bupivacaine during Labor

BackgroundThis randomized double-blind investigation was designed to study the placental transfer and neonatal effects of epidural sufentanil and fentanyl infused with bupivacaine for labor analgesia.

ED50 and ED95 of intrathecal hyperbaric bupivacaine coadministered with opioids for cesarean delivery

BackgroundSuccessful cesarean delivery anesthesia has been reported with use of small doses (5–9 mg) of intrathecal bupivacaine coadministered with opioids. This double-blind, randomized, dose-ranging study determined the ED50 and ED95 of intrathecal bupivacaine (with adjuvant opioids) for cesarean delivery anesthesia. MethodsForty-two parturients undergoing elective cesarean delivery with use of combined spinal–epidural anesthesia received intrathecal hyperbaric bupivacaine in doses of 6, 7, 8, 9, 10, 11, or 12 mg in equal volumes with an added 10 &mgr;g intrathecal fentanyl and 200 &mgr;g intrathecal morphine. Sensory levels (pinprick) were evaluated every 2 min until a T6 level was achieved. The dose was a success(induction) if a bilateral T6 block occurred in 10 min; otherwise, it was a failure(induction). In addition to being a success(induction), the dose was a success(operation) if no intraoperative epidural supplement was required; otherwise, it was a failure(operation). ED50 and ED95 for both success(induction) and success(operation) were determined with use of a logistic regression model. ResultsED50 for success(induction) and success(operation) were 6.7 and 7.6 mg, respectively, whereas the ED95 for success(induction) and success(operation) were 11.0 and 11.2 mg. Speed of onset correlated inversely with dose. Although no clear advantage for low doses could be demonstrated (hypotension, nausea, vomiting, pruritus, or maternal satisfaction), this study was underpowered to detect significance in these variables. ConclusionsThe ED95 of intrathecal bupivacaine under the conditions of this study is considerably in excess of the low doses proposed for cesarean delivery in some recent publications. When doses of intrathecal bupivacaine less than the ED95, particularly near the ED50, are used, the doses should be administered as part of a catheter-based technique.

Changes in the position of epidural catheters associated with patient movement

Background: Epidural catheter movement has been noted with change of patient position and can result in inadequate anesthesia. This study was designed to measure movement and to develop a technique that minimizes catheter displacement. Methods: In 255 parturients requesting epidural anesthesia for labor or cesarean section, a multiorificed lumbar epidural catheter was inserted with the patient in the sitting flexed position. The distance to the epidural space, length of catheter inserted, and amount of catheter position change as the patient moved from the sitting flexed to sitting upright and then to the lateral decubitus position were measured before the catheter was secured to the skin. Adequacy of analgesia, the need for catheter manipulation, and whether the patient was considered obese were noted. Data were grouped according to body mass index (BMI): 30 kg/m 2 . Results: The groups did not differ with respect to the length of catheter initially inserted or changes in catheter position between initial taping and removal. The distance to the epidural space differed significantly among the groups, increasing with greater BMI. Catheters frequently appeared to be drawn inward with position change from the sitting flexed to lateral decubitus position, with the greatest change seen in patients with BMI > 30. Only nine catheters were associated with inadequate analgesia, four of which were replaced. No analgesic failures occurred in the BMI > 30 group. In patients judged by the anesthesiologist to be obese or to have an obese back, BMI was greater, and the distance to the epidural space and the magnitude of catheter movement with position change were greater than in those who were not obese. Conclusions: Epidural catheters moved a clinically significant amount with reference to the skin in all BMI groups as patients changed position. If catheters had been secured to the skin before position change, many would have been pulled partially out of the epidural space. To minimize the risk of catheter displacement, particularly in obese patients, we recommend that multiorificed catheters be inserted at least 4 cm into the epidural space and that patients assume the sitting upright or lateral position before securing the catheter to the skin.

Single-Dose, Sustained-Release Epidural Morphine in the Management of Postoperative Pain After Elective Cesarean Delivery: Results of a Multicenter Randomized Controlled Study

In this multicenter, randomized, controlled study, we compared the analgesic efficacy and safety profile of a new single-dose extended-release epidural morphine (EREM) formulation (DepoDur™) with that of epidural morphine sulfate for the management of postoperative pain for up to 48 h after elective cesarean delivery. ASA physical status I or II parturients (n = 75) were anesthetized with a combined spinal/epidural technique. Parturients received intrathecal bupivacaine 12–15 mg and fentanyl 10 &mgr;g for spinal anesthesia and a single epidural injection of either 5 mg of standard (conventional preservative-free) morphine or 5, 10, or 15 mg of extended-release morphine after cord clamping for postoperative pain control. Single-dose EREM 10 and 15 mg groups significantly decreased total supplemental opioid medication use and improved functional ability scores for 48 h after surgery compared with those receiving 5 mg of standard morphine. Visual analog scale pain scores at rest and with activity at 24 to 48 h after dosing were significantly better in the 10- and 15-mg single-dose EREM groups versus the standard morphine group. There were no significant differences between the two 5 mg (single-dose EREM and standard morphine) groups. Single-dose EREM was well tolerated, and most adverse events were mild to moderate in severity. Single-dose EREM is a potentially beneficial epidural analgesic for the management of post-cesarean delivery pain and has particular advantages over standard morphine for the period from 24 to 48 h after surgery.

Patient preferences for anesthesia outcomes associated with cesarean delivery

When deciding on neuraxial medication (e.g., spinal opioids) for cesarean delivery (CS) under regional anesthesia, anesthesiologists make treatment decisions that “trade off” relieving pain with the potential for increased risk of side effects. No previous studies have examined obstetric patients’ anesthesia preferences. Researchers administered 100 written surveys to pregnant women attending our institutions’ expectant parent class. We determined patients’ preferences for importance of specific intraoperative and postoperative anesthesia outcomes using priority ranking and relative value scales. We also explored patients’ fears, concerns, and tolerance regarding CS and analgesics. Eighty-two of 100 surveys were returned and analyzed. Pain during and after CS was the greatest concern followed by vomiting, nausea, cramping, pruritus, and shivering. Ranking and relative value scores were closely correlated (R2 = 0.7). Patients would tolerate a visual analog pain score (0–100 mm) of 56 ± 22 before exposing their baby to the potential effects of analgesics they receive. In contrast to previous general surgical population surveys that found nausea and vomiting as primary concerns, we found pain during and after CS as parturients’ most important concern. Common side effects such as pruritus and shivering caused only moderate concern. This information should be used to guide anesthetic choices, e.g., inclusion of spinal opioids given in adequate doses.

Nalbuphine 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. The first dose of nalbuphine decreased the incidence of vomiting (P < 0.005) and the severity of nausea and pruritus (P < 0.01), whereas naloxone caused no significant changes. Sedation scores increased after nalbuphine (P < 0.05) and remained unchanged after naloxone, whereas pain scores increased after naloxone (P < 0.01) and were unchanged after nalbuphine. Eighteen patients in group 1 and 12 in group 2 received a second dose, and 8 and 4 patients, respectively, a third 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.