Left Lateral Table Tilt for Elective Cesarean Delivery under Spinal Anesthesia Has No Effect on Neonatal Acid-Base Status: A Randomized Controlled Trial.

BACKGROUND: Current recommendations for women undergoing cesarean delivery include 15° left tilt for uterine displacement to prevent aortocaval compression, although this degree of tilt is practically never achieved. We hypothesized that under contemporary clinical practice, including a crystalloid coload and phenylephrine infusion targeted at maintaining baseline systolic blood pressure, there would be no effect of maternal position on neonatal acid base status in women undergoing elective cesarean delivery with spinal anesthesia. METHODS: Healthy women undergoing elective cesarean delivery were randomized (nonblinded) to supine horizontal (supine, n = 50) or 15° left tilt of the surgical table (tilt, n = 50) after spinal anesthesia (hyperbaric bupivacaine 12 mg, fentanyl 15 µg, preservative-free morphine 150 µg). Lactated Ringer's 10 ml/kg and a phenylephrine infusion titrated to 100% baseline systolic blood pressure were initiated with intrathecal injection. The primary outcome was umbilical artery base excess. RESULTS: There were no differences in umbilical artery base excess or pH between groups. The mean umbilical artery base excess (± SD) was -0.5 mM (± 1.6) in the supine group (n = 50) versus -0.6 mM (± 1.5) in the tilt group (n = 47) (P = 0.64). During 15 min after spinal anesthesia, mean phenylephrine requirement was greater (P = 0.002), and mean cardiac output was lower (P = 0.014) in the supine group. CONCLUSIONS: Maternal supine position during elective cesarean delivery with spinal anesthesia in healthy term women does not impair neonatal acid-base status compared to 15° left tilt, when maternal systolic blood pressure is maintained with a coload and phenylephrine infusion. These findings may not be generalized to emergency situations or nonreassuring fetal status.

Validating Parallel-Forms Tests for Assessing Anesthesia Resident Knowledge.

We created a serious game to teach first year anesthesiology (CA-1) residents to perform general anesthesia for cesarean delivery. We aimed to investigate resident knowledge gains after playing the game and having received one of 2 modalities of debriefing. We report on the development and validation of scores from parallel test forms for criterion-referenced interpretations of resident knowledge. The test forms were intended for use as pre- and posttests for the experiment. Validation of instruments measuring the study's primary outcome was considered essential for adding rigor to the planned experiment, to be able to trust the study's results. Parallel, multiple-choice test forms development steps included: (1) assessment purpose and population specification; (2) content domain specification and writing/selection of items; (3) content validation by experts of paired items by topic and cognitive level; and (4) empirical validation of scores from the parallel test forms using Classical Test Theory (CTT) techniques. Field testing involved online administration of 52 shuffled items from both test forms to 24 CA-1's, 21 second-year anesthesiology (CA-2) residents, 2 fellows, 1 attending anesthesiologist, and 1 of unknown rank at 3 US institutions. Items from each form yielded near-normal score distributions, with similar medians, ranges, and standard deviations. Evaluations of CTT item difficulty (item p values) and discrimination (D) indices indicated that most items met assumptions of criterion-referenced test design, separating experienced from novice residents. Experienced residents performed better on overall domain scores than novices (P < .05). Kuder-Richardson Formula 20 (KR-20) reliability estimates of both test forms were above the acceptability cut of .70, and parallel forms reliability estimate was high at .86, indicating results were consistent with theoretical expectations. Total scores of parallel test forms demonstrated item-level validity, strong internal consistency and parallel forms reliability, suggesting sufficient robustness for knowledge outcomes assessments of CA-1 residents.

A randomized trial of breakthrough pain during combined spinal-epidural versus epidural labor analgesia in parous women.

BACKGROUND: There is controversy regarding the benefits and risks of combined spinal-epidural compared with epidural analgesia (CSE, EPID) for labor analgesia. We hypothesized that CSE would result in fewer patient requests for top-up doses compared to EPID. METHODS: One-hundred ASA physical status I or II parous women at term in early labor (<5 cm cervical dilation) requesting analgesia were randomized in double-blind fashion to the EPID group (epidural bupivacaine 2.5 mg/mL, 3 mL, followed by bupivacaine 1.25 mg/mL, 10 mL with fentanyl 50 microg) or the CSE group (intrathecal bupivacaine 2.5 mg with fentanyl 25 microg). Both groups received identical infusions of bupivacaine 0.625 mg/mL with fentanyl 2 microg/mL at 12 mL/h. The primary outcome variable was the number of top-up doses requested to treat breakthrough pain. RESULTS: There was no significant difference between the two groups in the percentage of patients requesting top-up doses (44% CSE vs 51% EPID; 95% confidence interval of the difference -28% to +14%) nor in the need for multiple top-up doses (14% CSE vs 15% EPID). Visual analog scale scores were lower in the CSE group compared to the EPID group at 10 min after initiation of analgesia [median 0 cm (0, 0) vs 4 cm (1, 6) respectively, P < 0.001] and at 30 min [0 cm (0, 0) vs 0 cm (0, 1), respectively, P = 0.03]. CONCLUSIONS: We did not find a difference in the need for top-up doses in parous patients; however, CSE provided better analgesia in the first 30 min compared to EPID.

Development of a Multiple-Choice Test for Novice Anesthesia Residents to Evaluate Knowledge Related to Management of General Anesthesia for Urgent Cesarean Delivery.

BACKGROUND: Teaching trainees the knowledge and skills to perform general anesthesia (GA) for cesarean delivery (CD) requires innovative strategies, as they may never manage such cases in training. We used a multistage design process to create a criterion-referenced multiple-choice test as an assessment tool to evaluate CA1's knowledge related to this scenario. METHODS: Three faculty created 33 questions, categorized as: (1) physiologic changes of pregnancy (PCP), (2) pharmacology (PHA), (3) anesthetic implications of pregnancy (AIP), and (4) crisis resource management principles (CRM). A Delphi process (3 rounds) provided content validation. In round 1, experts (n = 15) ranked questions on a 7-point Likert scale. Questions ranked ≥ 5 in importance by ≥ 70% of experts were retained. Five questions were eliminated, several were revised, and 1 added. In round 2, consensus (N = 14) was reached in all except 7 questions. In round 3 (N = 14), all questions stabilized. A pilot test of the 29-question instrument evaluating internal consistency, reliability, convergent validity, and item analysis was conducted with the July CA1 classes at our institution after a lecture on GA for CD (n = 26, "instructed group") and another institution with no lecture (n = 26, "uninstructed group"), CA2s (N = 17), and attendings (N = 10). RESULTS: Acceptable internal consistency and reliability was demonstrated (ρ = 0.67). Convergent validity coefficients between the CA1 uninstructed and instructed group suggested theoretical meaningfulness of the 4 sub-scales: PCP correlated at 0.29 with PHA, 0.35 with CRM, and 0.25 with AIP. PHA correlated with CRM and AIP at 0.23 and 0.28, respectively. The correlation between CRM and AIP was 0.29. CONCLUSION: The test produces moderately reliable scores to assess CA1s' knowledge related to GA for urgent CD.

Decreased postpartum use of oral pain medication after a single dose of epidural morphine.

BACKGROUND: Pain after vaginal delivery may result from episiotomy, perineal laceration, or uterine involution. Many women have indwelling epidural catheters in place at delivery. We hypothesized that a small dose of epidural morphine would be an effective strategy for postpartum analgesia. METHODS: Eighty-one healthy parturients receiving epidural analgesia for labor were enrolled. Patients were randomized in double-blind fashion to 1 of 3 groups: all groups received a 4-mL volume of epidural solution consisting of saline (group 1, control), 1 mg (group 2), or 2 mg morphine (group 3) after vaginal delivery. During the first 24 hours postpartum, patients were evaluated for the amount of oral pain medication requested; visual analog scale scores for pain at rest and with movement; satisfaction with postpartum pain treatment; and opioid side effects including nausea, pruritus, urinary retention, and respiratory depression. RESULTS: Patients who received 2 mg of epidural morphine used an average of 0.7 (0-1, interquartile range) opioid-containing pain pills (acetaminophen with codeine or oxycodone) compared with 1.2 (0-2) in the 1-mg group and 1.9 (0-3) in the control group ( P = .07). There was a statistically significant difference in oral drug usage between those who received epidural morphine and those who did not ( P < .03). There were no differences in side effects except that at 12 hours postpartum there was an increase in Foley catheterization in the 1-mg morphine group ( P = .007). CONCLUSIONS: These results suggest that epidural morphine decreases the need for oral pain medication in the first 24 hours postpartum. No significant dose-dependent side effects were found.

Epinephrine is not a useful addition to intrathecal fentanyl or fentanyl-bupivacaine for labor analgesia.

BACKGROUND AND OBJECTIVES: Intrathecal fentanyl provides effective labor analgesia for a limited time with frequent side effects. We evaluated the effects of adding epinephrine to intrathecal fentanyl with and without bupivacaine. METHODS: Eighty healthy, term, nulliparous parturients with cervical dilation of 5 cm or less received combined spinal-epidural (CSE) analgesia. Subjects were randomized in a double-blind fashion to 1 of 4 intrathecal solutions containing fentanyl 35 microg with either saline (F); bupivacaine 2.5 mg + saline (FB); bupivacaine 2.5 mg + epinephrine 100 microg (FBE); or epinephrine 100 microg + saline (FE). Patients were evaluated for visual analog pain score, duration of spinal analgesia (time until patient request for additional analgesia), nausea/vomiting, pruritus, sensory and motor block, maternal blood pressure, and fetal heart rate (FHR). RESULTS: Intrathecal bupivacaine significantly prolonged fentanyl analgesia with or without epinephrine (P =.018), but epinephrine did not significantly prolong the duration of fentanyl alone or with bupivacaine (F, 92 +/- 39 minutes; FB, 125 +/- 31 minutes; FBE, 134 +/- 42 minutes; and FE, 117 +/- 48 minutes). Intrathecal epinephrine was associated with a higher incidence of severe nausea (P =.001), and the FBE group had more lower extremity weakness (P =.047). There was no difference in the incidence of severe pruritus, FHR deceleration, or delivery outcome between the groups. CONCLUSIONS: These results suggest that intrathecal epinephrine does not prolong the duration of fentanyl or fentanyl with bupivacaine for labor analgesia in nulliparous parturients. Additionally, intrathecal epinephrine did not decrease the incidence of side effects and therefore cannot be recommended.