Etiology and incidence of endotracheal intubation following spinal anesthesia for cesarean section.

BACKGROUND: The incidence of spinal failure necessitating general anesthesia and endotracheal intubation following spinal anesthesia for cesarean section is extremely low. Aspiration prophylaxis prior to spinal anesthesia is often recommended in case of spinal failure or excessive spinal block requiring the emergency administration of general anesthesia. OBJECTIVES: To determine the incidence of endotracheal intubation following spinal anesthesia for cesarean section. METHODS: We retrospectively reviewed the peri-operative course of parturients undergoing cesarean section under spinal anesthesia at our institution from February 1991 to December 1993. If spinal failure occurred, 10 ml of sodium bicarbonate was administered by mouth prior to induction of general anesthesia. RESULTS: Among the 743 cases that we reviewed, spinal failure occurred in 15 patients (2%) because of inadequate analgesia in 14 patients (1.9%) and unexpected prolonged surgery for hysterectomy in one patient (0.1%). No patient required intubation due to excessive spinal block. In none of the patients was a record of pulmonary aspiration identified. CONCLUSIONS: The extremely low incidence of spinal failure or excessive block necessitating endotracheal intubation suggests that routine aspiration prophylaxis may not be necessary prior to spinal anesthesia. However, these results should be confirmed by a prospective, controlled study on larger populations. An antacid should be readily available and administered whenever general anesthesia is required.

Addition of dextrose 3.5% to intrathecal sufentanil for labour analgesia reduces pruritus.

PURPOSE: To determine whether the addition of a low concentration (3.5%) of dextrose would minimize pruritus while maintaining the quality of analgesia. METHODS: In a double blind study 48 parturients in early labour were randomized to one of two study groups: dextrose (Dex, n = 24; 10 microg sufentanil in dextrose 3.5%), or normal saline (NS, n = 24; 10 microg sufentanil in normal saline). Parturients received the study drug as the intrathecal injection of the combined spinal-epidural (CSE) technique for labour analgesia. Duration and degree of analgesia were measured until epidural analgesia was initiated or delivery of the baby. The intensity and distribution (above T6, T6-L1, and below L1) of pruritus were measured at five minute intervals during first 25 min after injection. RESULTS: Quality and duration of analgesia did not differ between groups, but the overall incidence of pruritus was less in the Dex group (88% vs 42%, P = 0.001). Within each region, the incidence of pruritus was less in the Dex group. In patients who had pruritus, for the Dex group, the incidence of pruritus in the upper region (>T6) was lower than the NS group. There was no difference in the lower regions. CONCLUSION: The addition of dextrose 3.5% to intrathecal sufentanil reduced the incidence of pruritus without affecting the duration or quality of analgesia in parturients in early labour. The distribution of pruritus in the Dex group was limited to below T6 suggesting that pruritus to intrathecal sufentanil is mediated at the spinal level.

Ondansetron versus placebo for the control of nausea and vomiting during Caesarean section under spinal anaesthesia.

This prospective, randomised, placebo-controlled, double-blind study was performed to evaluate the effects of ondansetron on nausea and vomiting during elective Caesarean section under spinal anaesthesia. Seventy-four full-term parturients were studied. After umbilical-cord clamping, ondansetron 4 mg or 0.9% saline was injected intravenously and the study period continued for 2 h. The severity of nausea was graded from 0 = none to 10 = maximum, while that of vomiting was graded from single = once per min to continuous = multiple per min. The incidence of vomiting was lower following ondansetron (36%) compared with the control group (58%, p < 0.028). Neither the severity of vomiting nor the incidence of nausea was influenced by ondansetron. However, for those who experienced nausea, ondansetron reduced its severity (p = 0.05). We conclude that the intra-operative administration of 4 mg ondansetron intravenously during Caesarean section under spinal anaesthesia significantly reduces the incidence of vomiting and the severity of nausea.

Rapacuronium for modified rapid sequence induction in elective caesarean section: neuromuscular blocking effects and safety compared with succinylcholine, and placental transfer.

We have compared rapacuronium 2.5 mg kg-1 (n = 20) with succinylcholine 1.5 mg kg-1 (n = 22) in a multicentre, blinded, randomized study in full-term parturients undergoing elective Caesarean section under general anaesthesia. Thiopental 5 mg kg-1 was given i.v. followed by the neuromuscular blocking agent. Sixty seconds later intubation was performed. Intubating conditions, evaluated as excellent, good or poor, were good to excellent in 95% and 91% in the intent-to-treat patients after rapacuronium and succinylcholine, respectively (ns). Mean onset times at the adductor pollicis muscle for rapacuronium and succinylcholine were 80.4 (SEM 14.4) s and 63.9 (5.6) s (ns) while maximum block was 96 (1.9)% and 99 (0.4)%, respectively (ns). Rate of recovery was significantly longer after rapacuronium; times for return of T1 to 25% were 16.9 (1.5) min and 9.6 (1.1) min for rapacuronium and succinylcholine, respectively (P = 0.0004). Maternal side effects included more tachycardia and skin erythema with rapacuronium; no maternal mortality or morbidity, including bronchospasm, occurred in either group. There were no neonatal adverse effects in either group based on: Apgar scores at 1 and 5 min; times to sustained respiration; neuroadaptive capacity scores at 15 min, 2 h and 24 h; and umbilical venous and arterial blood-gas values and acid-base status. At delivery (17.7 (3.2) min), mean maternal plasma concentrations of rapacuronium were 9041.4 (1259.1) ng ml-1 and 506.4 (24.9) ng ml-1 for Org 9488 (the main metabolite). Corresponding values for umbilical venous plasma were 808.0 (92.1) ng ml-1 and 59.1 (6.5) ng ml-1, and for umbilical arterial plasma, 361.4 (56.4) ng ml-1 and 29.7 (4.6) ng ml-1, respectively. Umbilical venous to maternal venous ratios for rapacuronium and Org 9488 were 8.8% (1.3)% and 10.2 (1.7)%, respectively.

Combined spinal and epidural anesthesia for cesarean section in a parturient with moyamoya disease.

We present the case of a parturient with moyamoya disease admitted to the hospital for elective cesarean section. Combined spinal and epidural technique was chosen because it allows better analgesia than epidural anesthesia and more hemodynamic stability than either general or spinal anesthesia. Ropivacaine was the local anesthetic of choice for the epidural portion because of the wide sensory-motor dissociation, thus preserving adequate respiration in the case of a high block.

Ropivacaine-induced seizure after extradural anaesthesia.

Ropivacaine is considered safer than bupivacaine, on the basis of experimental and human data that indicate a lower systemic toxicity. Here we report the occurrence of a single seizure after i.v. administration of ropivacaine 120 mg intended for extradural block in a patient having postpartum, tubal ligation. The only prodromal symptom was nervousness, and the only cardiovascular manifestation was sinus tachycardia. Systemic toxicity, although less than that expected with bupivacaine, can occur with ropivacaine.

Heparinase-guided thrombelastography in an anticoagulated parturient.

We describe the use of heparinase-guided thrombelastography in the assessment of a parturient who had been anticoagulated with heparin for suspected thromboembolic disease. Reversal of the heparin effect in the heparinase-treated sample facilitated administration of protamine and successful subarachnoid analgesia for delivery.

Fetal heart rate changes after intrathecal sufentanil or epidural bupivacaine for labor analgesia: incidence and clinical significance.

The objective of this study was to compare the incidence of intrapartum fetal heart tracing (FHT) abnormalities and the obstetric outcome after intrathecal sufentanil (ITS) versus epidural bupivacaine (EB). During the period from April to September 1994, 129 patients who met inclusion criteria were prospectively identified during labor at a single university-affiliated hospital. Inclusion criteria included: singleton, gestational age > or = 36 wk, and cephalic presentation. In the ITS group, epidural anesthesia was not administered before 60 min after ITS. Sixty-five consecutive ITS patients were compared to 64 consecutive EB patients. Each FHT was reviewed independently by two obstetricians blinded to the type of analgesia. The FHT characteristics evaluated included baseline rate, variability, and periodic changes. No differences in the incidence of clinically significant FHT abnormalities (recurrent late decelerations and/or bradycardia) were observed between the two groups (ITS 21.5% versus EB 23.4%). The rates of clinically significant FHT abnormalities in both groups was not different when patients with hypotension and medical complications were excluded (16.9% vs 17.1%). In addition, equal rates of hypotension (18.5% vs 17.2%) were noted between the groups. In both groups there was a significantly higher risk of cesarean section in patients whose previously normal FHT became abnormal postanalgesia when compared to patients without a new onset FHT abnormality (ITS 28.6% [4/14] versus 2.0% [1/51], P < 0.01; EB 33.3% [5/15] versus 8.2% [4/49], P < 0.05). This increased risk was associated with an increase in cesarean section for nonreassuring FHT in both groups (ITS 14.3% [2/14] versus 0% [0/51], P = 0.04; EB 13.3% [2/15] versus 0% [0/49], P = 0.05). These results support the conclusion that the incidence of clinically significant FHT abnormalities and hypotension is equivalent in patients receiving ITS when compared to EB within the first hour of administration. During this period, patients should have continuous FHT monitoring since a new onset FHT abnormality unveils and alerts the physicians to a possible compromised fetal condition and a corresponding increased risk of cesarean section.

Effect of epidural analgesia on fundal dominance during spontaneous active-phase nulliparous labor.

BACKGROUND: The purpose of this investigation was to determine if epidural analgesia, established during active phase labor, results in elimination or reversal of fundal dominance (lower uterine segment pressure equal to or greater than fundal pressure). METHODS: Upper and lower uterine segment intrauterine pressures were prospectively evaluated for 50 min before and 50 min after epidural analgesia using 0.25% bupivacaine in 11 nulliparous women in spontaneous active labor. A total of 958 contractions were evaluated. RESULTS: No significant differences were found in the number of contractions in the interval before epidural analgesia compared to after epidural analgesia. Significantly greater pressure readings were recorded in the upper segment than in the lower segment (consistent with fundal dominance) both before and after epidural analgesia (P<0.01). In addition, fundal dominance increased after epidural analgesia when compared to the preanalgesia period (P<0.01). CONCLUSIONS: Fundal dominance is present both before and after active phase epidural analgesia and is increased during the immediate 50-min postanalgesia period.

Anaesthetic management of acute puerperal uterine inversion.

We identified 18 cases of acute puerperal uterine inversion after vaginal delivery out of 65,581 deliveries in two university-affiliated hospitals (an incidence of 1:3643). In all cases manual repositioning of the uterus without tocolysis was attempted. In four cases this was successful. Of the 14 patients requiring tocolysis, a single dose of terbutaline 0.25 mg i.v. was tried in eight and was successful in five cases (success rate of 63%), while in three patients general anaesthesia was required. In six other patients, general anaesthesia was chosen as the initial management. There was no associated maternal mortality or morbidity with the exception of one case of acute postpartum endometritis. We suggest that when tocolysis is required, terbutaline should be used first because of its rapid onset of action, short duration, simplicity, availability in the labour suite and familiarity to the obstetrician, and general anaesthesia, with its inherent dangers, if possible, should be avoided.