The effect of anti-emetic doses of dexamethasone on postoperative blood glucose levels in non-diabetic and diabetic patients: a prospective randomised controlled study.

There are few data regarding postoperative hyperglycaemia in non-diabetic compared with diabetic patients following postoperative nausea and vomiting prophylaxis with dexamethasone. Eighty-five non-diabetic patients and patients with type-2 diabetes were randomly allocated to receive intravenous dexamethasone (8 mg) or ondansetron (4 mg). Blood glucose levels were measured at baseline and then 2, 4 and 24 h following induction of anaesthesia. In non-diabetic patients, the mean (SD) maximum blood glucose was higher in those who received dexamethasone compared with ondansetron (9.1 (2.2) mmol.l(-1) vs. 7.8 (1.4) mmol.l(-1) , p = 0.04). In diabetic patients, the mean (SD) maximum blood glucose was also higher in those who received dexamethasone compared with ondansetron (14.0 (2.5) mmol.l(-1) vs. 10.7 (2.4) mmol.l(-1) , p < 0.01). Multivariate analysis demonstrated that dexamethasone administration was a significant predictor of maximum postoperative blood glucose increase (p < 0.01) after adjusting for potential confounders. There was no interaction between baseline blood glucose level, or presence or absence of diabetes, and dexamethasone administration. We conclude that dexamethasone increases postoperative blood glucose levels in both non-diabetics and diabetics.

A conundrum: general or neuraxial anesthesia and the use of ROTEM.

We report the use of rotational thromboelastometry (ROTEM) to guide the management of a 29-year-old primigravida at 36weeks' gestation with portal hypertension, esophageal varices, suspected pseudocholinesterase deficiency, and steroid refractory thrombocytopenia presenting to labor and delivery with worsening peripheral edema and new-onset hypertension. A multidisciplinary decision for preoperative platelet transfusion and cesarean delivery under spinal anesthesia was made, guided by ROTEM. A successful cesarean delivery was performed with no bleeding complications.

The impact of gestational age and fetal weight on the risk of failure of spinal anesthesia for cesarean delivery.

BACKGROUND: There are limited data about spinal dosing for cesarean delivery in preterm parturients. We investigated the hypothesis that preterm gestation is associated with an increased incidence of inadequate spinal anesthesia for cesarean delivery compared with term gestation. METHODS: We searched our perioperative database for women who underwent cesarean delivery under spinal or combined spinal-epidural anesthesia with hyperbaric bupivacaine ⩾10.5mg. The primary outcome was the incidence of inadequate surgical anesthesia needing conversion to general anesthesia or repetition or supplementation of the block. We divided patients into four categories: <28, 28 to <32, 32 to <37 and ⩾37weeks of gestation. The chi-square test was used to compare failure rates and a multivariable regression analysis was performed to investigate potential confounders of the relationship between gestational age and failure. RESULTS: A total of 5015 patients (3387 term and 1628 preterm) were included. There were 278 failures (5.5%). The incidence of failure was higher in preterm versus term patients (6.4% vs. 5.1%, P=0.02). Failure rates were 10.8%, 7.7%, 5.3% and 5% for <28, 28 to <32, 32 to <37 and ⩾37weeks of gestation, respectively. In the multivariable model, low birth weight (P<0.0001), gestational age (P=0.03), ethnicity (P=0.02) and use of combined spinal-epidural anesthesia (P<0.0001) were significantly associated with failure. CONCLUSIONS: At standard spinal doses of hyperbaric bupivacaine used in our practice (⩾10.5mg), there were higher odds of inadequate surgical anesthesia in preterm parturients. When adjusting for potential confounders, low birth weight was the main factor associated with failure.

Refractory status epilepticus after inadvertent intrathecal injection of tranexamic acid treated by magnesium sulfate.

We present a case of accidental injection of tranexamic acid during spinal anesthesia for an elective cesarean delivery. Immediately following intrathecal injection of 2mL of solution, the patient complained of severe back pain, followed by muscle spasm and tetany. As there was no evidence of spinal block, the medications given were checked and a 'used' ampoule of tranexamic acid was found on the spinal tray. General anesthesia was induced but muscle spasm and tetany persisted despite administration of a non-depolarizing muscle relaxant. Hemodynamic instability, ventricular tachycardia, and status epilepticus developed, which were refractory to phenytoin, diazepam, and infusions of thiopental, midazolam and amiodarone. Magnesium sulfate was administered postoperatively in the intensive care unit, following which the frequency of seizures decreased, eventually stopping. Unfortunately, on postoperative day three the patient died from cardiopulmonary arrest after an oxygen supply failure that was not associated with the initial event. This report underlines the importance of double-checking medications before injection in order to avoid a drug error. As well, it suggests that magnesium sulfate may be useful in stopping seizures caused by the intrathecal injection of tranexamic acid.

Minimum effective dose of spinal ropivacaine with and without fentanyl for postpartum tubal ligation.

BACKGROUND: Ropivacaine may be the ideal spinal anesthetic for postpartum tubal ligation due to its medium duration of action, low incidence of side effects and possibly reduced post-anesthetic care unit (PACU) stay. METHODS: Two prospective up-down sequential allocation studies were performed using hyperbaric spinal ropivacaine via a combined spinal-epidural anesthetic technique for patients undergoing postpartum tubal ligation. The first study was performed using an initial dose of 12.5 mg hyperbaric ropivacaine, which was adjusted in testing intervals of 0.5 mg. The second study used an initial dose of 16 mg hyperbaric ropivacaine, a testing interval of 1.0mg, and a fixed dose of fentanyl 10 µg. The need to supplement the block with intravenous or epidural agents was defined as a failure. Failures were treated with epidural lidocaine. RESULTS: The first and second studies recruited 24 and 17 patients, respectively. The median effective dose (ED50) for hyperbaric spinal ropivacaine was 16.4 mg (95% CI 13.7-19) with an ED95 estimate of 21.9 mg. The median effective dose of spinal ropivacaine with fentanyl 10 µg was 17.0 mg (95% CI 15.4-18.7) with an ED95 estimate of 21.3 mg. When data were combined, the overall ED50 for ropivacaine was 16.7 mg (95% CI 15.1-18.4) with an ED95 estimate of 22.5 mg (95% CI 16.3-28.8). A T8 block was not achieved in 4 patients receiving spinal ropivacaine alone, and 1 patient receiving spinal ropivacaine with fentanyl. The majority (82%) of patients who did not receive epidural local anesthetic supplementation had recovery of motor block within 60 min following PACU admission. CONCLUSION: Spinal hyperbaric ropivacaine 22 mg with or without fentanyl 10 µg could be used for postpartum tubal ligation surgery.

Caesarean section in a patient with torsion dystonia.

We present a case of torsion dystonia in a 35-yr-old primigravida who presented for a Caesarean section under general anaesthesia. She had limb contractures and severe kyphoscoliosis associated with limited respiratory reserve and function. General anaesthesia was induced using thiopental and divided doses of mivacurium for rapid sequence induction. After the delivery of a healthy male baby, she received i.v. morphine and bilateral iliohypogastric, ilioinguinal blocks and had an uneventful recovery. Technical issues of supine positioning, intubation and respiratory support need to be considered during anaesthesia planning. Although regional anaesthesia is commonly offered for caesarean section, maternal compromise and technical factors may preclude this approach.

A randomized, prospective double-blind comparison of the efficacy of generic propofol (sulphite additive) with diprivan.

BACKGROUND AND OBJECTIVE: We compared the dose requirement and side effect profile of total intravenous anaesthesia using Diprivan to generic propofol at a specific anaesthetic target level utilizing the bispectral index monitor to determine efficacy differences between the two products. METHODS: Sixty women undergoing abdominal hysterectomy were induced with propofol 2 mg kg-1 and maintained with infusion (20-200 microg kg-1 min-1) adjusted to maintain a bispectral index of 50-65. Plasma propofol concentration was measured at 1 and 2 h post induction in 25 patients. RESULTS: Mean (SD) drug doses adjusted for weight and time were similar in the Diprivan and generic propofol groups: 90 (30) microg kg-1 min-1 vs. 90 (20) microg kg-1 min-1 respectively. Mean (SD) plasma propofol levels at 1 and 2 h were also similar (3.0 (1.0) microg mL-1 vs. 3.6 (1.4) microg mL-1, P = 0.2 and 3.0 (1.9) microg mL-1 vs. 3.4 (1.6) microg mL-1, P = 0.58). CONCLUSIONS: Diprivan and generic propofol have similar efficacy at a specified, bispectral index-defined, depth of anaesthesia.

Effect of head posture on tracheal tube position in children.

Changes in the tracheal tube tip to carina distance were measured by radiographic screening following various head postures in 45 children undergoing cardiac catheterisation under general anaesthesia who were intubated via nasal and oral routes. Extension of the head moved the tracheal tube away from the carina and flexion moved it towards the carina in both routes. Endobronchial intubation was noted during neck flexion in a significant proportion of children intubated orally but none occurred during nasal intubation. Extension produced greater upward movement of the tracheal tube tip in the oral route than the nasal route. In contrast, flexion produced greater downward movement in the nasal route in some patients. The direction of movement with lateral rotation and use of a shoulder roll was inconsistent.

Use of implantable cardioverter defibrillator and anti-arrhythmic agents in a parturient.

We describe a case of a 36-yr-old patient who presented at 14 weeks gestation with multifocal dysrrhythmic episodes. Despite treatment with anti-arrythmic agents and an implantable cardioverter defibrillator (ICD) in situ, she continued to experience persistent dysrrhythmic episodes. She was delivered by Caesarean section at 34 weeks under general anaesthesia. We discuss some of the anaesthetic challenges of parturients with ICD devices.

A preliminary investigation of remifentanil as a labor analgesic.

IMPLICATIONS: In this preliminary investigation, we evaluated the safety and analgesic efficacy of IV remifentanil for labor pain. Four women were studied, and then the trial was terminated because administration of this novel synthetic opioid produced significant maternal side effects in the absence of effective pain control.

Subarachnoid meperidine (Pethidine) causes significant nausea and vomiting during labor. The Duke Women's Anesthesia Research Group.

BACKGROUND: The combined spinal-epidural (CSE) technique using bupivicaine-fentanyl has become an established method of pain control during parturition. One limitation is the relatively short duration of effective analgesia produced by bupivicaine-fentanyl. In contrast, subarachnoid meperidine has been shown to provide a long duration of anesthesia in nonobstetric patients. Therefore, the authors tested the hypothesis that subarachnoid meperidine produces a significant increase in the duration of analgesia compared with bupivicaine-fentanyl. METHODS: Based on a power analysis of preliminary data, the authors intended to recruit 90 patients for the study, randomized to three groups: 2.5 mg bupivicaine-25 microg fentanyl, 15 mg meperidine, or 25 mg meperidine. However, after enrolling 34 patients, the study was discontinued because of a significant increase in nausea or vomiting in the study patients. RESULTS: Nausea or vomiting was substantially increased in both meperidine groups compared with the bupivicaine-fentanyl group: 16 with nausea or vomiting in the meperidine groups (n = 21), compared with 1 in the bupivicaine-fentanyl group (n = 11), P = 0.0011. The mean duration of analgesia provided by 25 mg meperidine was 126 +/- 51 min, compared with 98 +/- 29 min for bupivicaine-fentanyl and 90 +/- 67 min for 15 mg meperidine. These data were not significant (P = 0.27). CONCLUSIONS: Although intrathecal meperidine could potentially prolong subarachnoid analgesia during labor, its use was associated with a significant incidence of nausea or vomiting. These data do not support the use of subarachnoid meperidine in doses of 15 or 25 mg for labor analgesia.

Comparison of remifentanil with alfentanil or suxamethonium following propofol anaesthesia for tracheal intubation.

Sixty ASA physical status I and II, premedicated patients were administered propofol 2 mg x kg-1 and remifentanil 2 microg x kg-1 (group R), alfentanil 50 microg x kg-1 (group A) or suxamethonium 1 mg x kg-1 (group S) as a rapid bolus. One minute after study drug administration, tracheal intubation was performed. Intubation conditions were then scored. Excellent or good conditions were observed in only 35% in group R compared with groups S and A (100% and 85%, respectively; p < 0.001). The haemodynamic response to tracheal intubation was blunted in groups R and A compared with group S (p < 0.001). The mean heart rate in groups R and A was significantly lower than group S (p < 0.001). We conclude that remifentanil 2 microg x kg-1 given as a rapid bolus will not produce intubating conditions as good as those obtained with alfentanil 50 microg x kg-1 or suxamethonium 1 mg x kg-1 if administered after propofol 2 mg x kg-1.

Dosing study of remifentanil and propofol for tracheal intubation without the use of muscle relaxants.

Sixty ASA I and II patients, premedicated with midazolam, were administered propofol 2 mg x kg-1 and remifentanil 3 microg x kg-1 (group R3), remifentanil 4 microg x kg-1 (group R4) and remifentanil 5 microg x kg-1 (group R5). Laryngoscopy and intubation were performed 1 min after the administration of the study drugs and the intubating conditions were assessed. Good to excellent conditions were observed in 12 patients in group R3 compared with 19 patients each in groups R4 and R5 (p = 0.004). Significant reductions in mean arterial pressure (MAP) and heart rate (HR) after administration of the study drug were observed in each group, p < 0.01. There was, however, no difference in mean MAP and HR between the three groups at all time points. We conclude that remifentanil 4-5 microg x kg-1 may reliably provide good to excellent conditions for tracheal intubation when administered after propofol 2 mg x kg-1.