Neonatal effects after vasopressor during spinal anesthesia for cesarean section: a multicenter, randomized controlled trial

BACKGROUND

Placental transfer of ephedrine causes fetal effects when compared with phenylephrine. This study compared their drug effects on neonatal parameters after cesarean delivery under spinal anesthesia.

METHODS

Three-hundred-and-fifty-four women undergoing elective cesarean delivery who needed intravenous vasopressor following spinal anesthesia were randomized into two groups. Group E received boluses of ephedrine 6mg, and Group P phenylephrine 100µg, titrated to maintain systolic blood pressure near baseline values. Neonatal heart rates at 10 and 30-45min of age, oxygen saturation and capillary blood glucose at 30min, and capillary blood lactate and urine metamphetamine were recorded.

RESULTS

Neonatal heart rate at 10min was significantly higher (mean difference 4.0, 95%CI 0.6 to 7.3, P=0.02) in Group E versus Group P, but this was not clinically relevant. There was a linear correlation between neonatal heart rate at 10min and ephedrine dose in Group E (r²=0.29, 95%CI 0.22, 0.74, p<0.01). The decremental changes in neonatal heart rate at 10 and 30min were significantly greater in Group E. Urine metamphetamine tests were positive in 19% of 44 neonatal urine samples. Neonatal heart rates at 30min, oxygen saturation, capillary blood glucose and the incidence of tachycardia, respiratory problems or abnormal glucose, were not significantly different.

CONCLUSIONS

Ephedrine, compared to phenylephrine as a vasopressor during cesarean delivery, was associated with higher neonatal heart rate in the early post-birth period, but without a significant difference in clinical outcomes in uncomplicated pregnancies.

Poor prognostic value of the modified Mallampati score: a meta-analysis involving 177 088 patients

The modified Mallampati score is used to predict difficult tracheal intubation. We have conducted a meta-analysis of published studies to evaluate the Mallampati score as a prognostic test. A total of 55 studies involving 177 088 patients were included after comprehensive electronic and manual searches. The pooled estimates from the meta-analyses were calculated based on a random-effects model and a summary receiver operating curve. Meta-regression analyses were performed to explore sources of possible heterogeneity between the studies. The summary receiver operating curve demonstrated an area under the curve of 0.75. The pooled odds ratio for a difficult intubation with a modified Mallampati score of III or IV was 5.89 [95% confidence interval (CI), 4.74-7.32]. The pooled estimates of the specificity and sensitivity were 0.91 (CI, 0.91-0.91) and 0.35 (CI, 0.34-0.36), respectively. The pooled positive and negative likelihood ratios were 4.13 (CI, 3.60-4.66) and 0.70 (CI, 0.65-0.75), respectively. The meta-analyses had statistical and clinical heterogeneity ranging from 87.2% to 99.4%. Meta-regression analyses did not identify any significant explanation of the heterogeneity. We conclude that the prognostic value of the modified Mallampati score was worse than that estimated by previous meta-analyses. Our assessment shows that the modified Mallampati score is inadequate as a stand-alone test of a difficult laryngoscopy or tracheal intubation, but it may well be a part of a multivariate model for the prediction of a difficult tracheal intubation.

Anesthesia for Indian Ocean tsunami-affected patients at a southern Thailand provincial hospital

BACKGROUND

On 26 December 2004, a giant earthquake shook South-East Asia, triggering deadly flood waves (tsunami) across the Indian Ocean. The Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand joined the Thai Red Cross Society to provide relief in southern Thailand. The objective of this article is to characterize the emergency surgical patients and anesthesia profiles of tsunami victims at Phang-Nga Provincial Hospital.

METHODS

Available records from the operating room and anesthesia unit of Phang-Nga Provincial Hospital, together with laboratory and administrative data, during the period 26-31 December 2004 were collected and analyzed using descriptive statistics.

RESULTS

Thai Red Cross teams provided surgical emergency services for 107 cases during 28-30 December 2004. Ninety-three cases (86%) were Caucasian, one (0.9%) was Japanese and nine (8.4%) were Thai. ASA physical status classifications of 1, 2 and 3 were present in 87.8%, 8.4% and 0.4%, respectively. The majority of injuries comprised multiple soft tissue wounds with severe infection. Eighty-five per cent of cases received debridement and 14.0% tendon or nerve repair or fixation of bone. The anesthesia choices were general endotracheal with rapid sequence induction and intubation (69.2%), general under mask (19.6%), total intravenous anesthesia (4.7%), spinal anesthesia (3.7%) and local anesthesia (2.8%). Anesthesia-related problems included a lack of pre-operative laboratory investigation, hypovolemia, severe wound infection with early sepsis and aspiration pneumonia. Common intra-operative complications included hypotension and oxygen desaturation from pulmonary aspiration or lung contusion. There was one case of post-operative reintubation and no peri-operative mortality.

CONCLUSION

Anesthesia-related problems in tsunami victims included pulmonary aspiration, hypovolemia, sepsis and lack of pre-operative laboratory investigation. General anesthesia was the most common anesthetic technique. Common intra-operative complications included hypotension and oxygen desaturation.

Nicardipine versus lidocaine for attenuating the cardiovascular response to endotracheal intubation

PURPOSE

The aim of this study was to compare the efficacy of nicardipine and lidocaine in attenuation of cardiovascular responses to endotracheal intubation.

METHODS

In a randomized, double-blind, controlled trial, 60 unpremedicated (ASA I) patients undergoing elective surgery were given either 30 microg.kg(-1) nicardipine or 1.5 mg.kg(-1) lidocaine intravenously 2 min before intubation. Laryngoscopy and tracheal intubation were performed 1 min after induction of anesthesia with 5 mg.kg(-1) thiopentone, followed by administration of 1.5 mg.kg(-1) succinylcholine intravenously. Blood pressure and heart rate were monitored at baseline and every minute until 4 min after intubation. Repeated-measures ANOVA, Student's t test, the chi-square test, and 95% confidence intervals were used as appropriate. P < 0.05 was considered statistically significant.

RESULTS

Baseline hemodynamic variables were not different between the groups. After administration of either agents, diastolic blood pressure and mean blood pressure were significantly lower in the nicardipine group. The heart rate in the nicardipine group was significantly higher. The mean between-group differences in diastolic blood pressure, mean blood pressure, heart rate, and rate-pressure product at baseline and 1 min after starting laryngoscopy were statistically significant.

CONCLUSION

Nicardipine can be used as an alternative to lidocaine in attenuation of cardiovascular response to tracheal intubation in patients without ischemic heart disease.

Nalbuphine versus propofol for treatment of intrathecal morphine-induced pruritus after cesarean delivery

In this prospective, randomized, double-blinded study, we compared the efficacy of nalbuphine and propofol for treating intrathecal morphine-induced pruritus after cesarean delivery. One-hundred-eighty-one parturients who developed moderate to severe pruritus after the administration of intrathecal morphine were randomly allocated into two groups. One group received 3 mg IV nalbuphine (n = 91), and the other received 20 mg IV propofol (n = 90). The improvement of pruritus and other adverse effects was determined at 10 min after study drug administration. The treatment success rate was higher in the Nalbuphine group than in the Propofol group (83% vs 61%; P < 0.001). Among the successfully treated patients, recurrence rates of moderate to severe pruritus within 4 h were not significantly different (nalbuphine 9% versus propofol 7%; P = 0.76). Other side effects, such as decreased analgesia, increased nausea, vomiting, increased sedation, pain on injection, and dizziness, were not significantly different between groups. Sedation and pain on injection, which were the two most common side effects, were minor and clinically inconsequential.

IMPLICATIONS

Nalbuphine was superior to propofol for the treatment of intrathecal morphine-induced pruritus after cesarean delivery.

Learning manual skills in spinal anesthesia and orotracheal intubation: is there any recommended number of cases for anesthesia residency training program?

Wide variability exists in the number of anesthetic procedures to which anesthesia residents are exposed during their training. The number of attempts at various procedures before a trainee becomes proficient at performing each anesthetic procedure is not known. To determine the learning process of 150 attempts of spinal anesthesia and 100 attempts of orotracheal intubation, the two most frequent anesthetic procedures, we evaluated 9 first-year anesthesia residents according to their rate of success or failure. The learning curves of both procedures revealed an initial rapid improvement of success during the first 20 attempts. Spinal anesthesia was more difficult to learn (p=0.0002) but the learning curves of spinal anesthesia and orotracheal intubation reached a nondifferent high success rate of 82 per cent and 88.9 per cent respectively (p=0.13). According to this study the institutional recommended number of cases for spinal anesthesia and orotracheal intubation were 112 and 27 cases respectively.

Hypotension in spinal anesthesia for cesarean section: a comparison of 0.5% hyperbaric bupivacaine and 5% hyperbaric lidocaine

Hypotension is a common side effect associated with spinal anesthesia. However, there is no previous report comparing the incidence of hypotension between two commonly used local anesthetic agents, bupivacaine and lidocaine. The objective of this study was to compare the incidence of spinal hypotension induced by bupivacaine and lidocaine in parturients undergoing cesarean section. A double blind, randomized controlled trial was conducted in 142 parturients scheduled for cesarean section. The patients were randomized into two groups, 71 each. After receiving 10 ml/kg of normal saline intravenously, patients in the first group were given 2.2 ml of 0.5 per cent hyperbaric bupivacaine plus 0.2 mg of morphine as a spinal anesthetic agent while in the other group, 1.2 ml of 5 per cent hyperbaric lidocaine plus 0.1 mg of epinephrine and 0.2 mg of morphine were administered. Hypotension, defined as 30 per cent less systolic blood pressure than baseline value, was recorded and the patients were treated with 6 mg of ephedrine every 2 minutes until normotension was achieved. There was no statistically significant difference of incidence, onset, duration, and severity of hypotension between the two groups (p > 0.05). The amount of ephedrine used in both groups was also not significantly different. Late onset hypotension occurred after delivery (20-22 minutes after spinal anesthesia was performed) in 17 patients (12%). As such, the rate of hypotension in lidocaine group was comparable to bupivacaine group. Delayed onset hypotension occurring after delivery was noted and these events have never been described. However, the mechanism of late onset hypotension remains unidentified. Thus, bupivacaine and lidocaine can be used interchangeably for spinal anesthesia for elective cesarean section without significant difference in the incidence of hypotension.

Ondansetron for treatment of intrathecal morphine-induced pruritus after cesarean delivery

BACKGROUND AND OBJECTIVES

Pruritus induced by intrathecal morphine is a concern in many obstetric patients after cesarean delivery and may detract from the benefit of postoperative pain relief. This study was performed to investigate the efficacy of ondansetron (5-HT3 receptor antagonist) in treatment of pruritus following intrathecal morphine.

METHODS

Eighty parturients developing moderate to severe pruritus following intrathecal morphine were randomly allocated into 2 groups. One group received 4 mg ondansetron while the other group received placebo (normal saline). The improvement of pruritus and other adverse effects such as pain scores, nausea, vomiting, sedation, hallucination, and respiratory depression were determined at 30 minutes after study drugs' administration.

RESULTS

The treatment success rate was higher in the ondansetron group than in the placebo group (80% v 36%, P < .001). Among the successfully treated patients, the recurrence rates of moderate to severe pruritus within 4 hours after administration of ondansetron and placebo were 12% and 70%, respectively (P < .001). The number of patients with decreased nausea and vomiting score was also higher in the ondansetron group (11 v 1, P < .006).

CONCLUSION

Ondansetron treats intrathecal morphine-induced pruritus after cesarean delivery, particularly in patients suffering from both nausea/vomiting and pruritus.

Effect of national seminar on AIDS and anesthesia upon knowledge, attitude and practice concerning HIV among Thai anesthesia personnel

In the national seminar of AIDS and Anesthesia which was a short course educational program in all aspects of HIV medicine, 195 questionnaires about knowledge, attitude and practice concerning HIV were distributed among the participants (anesthesiologists and nurse anesthetists) in 3 periods, pretest, post test (at the end of 2 days seminar) and post test 2 (at 4 months after the seminar). There were 177 (90.76%) respondents who completed both pretest and post test 1 questionnaires. About 12 questions of knowledge; mean scores were statistically significantly increased; 7.95 (0.98) vs 9.5 (0.78), P < 0.001. Two thirds (8 out of 12 questions) were answered correctly in post test 1 more than in the pretest by Mc Nemar Chi-square test; P < 0.05. About attitude; 2 out of 5 answers changed significantly by Mc Nemar Chi-square test; P < 0.05. The post test 2 questionnaires were mailed to all 177 participants twice asking to reply only once. All questionnaires were to be completed anonymously. The post test 2 with a response rate of 65.5 per cent revealed that universal precautions were frequently used among Thai anesthesia personnel but not universally followed. At least one-third of the respondents admitted recapping before disposal of used needles. Fifty six per cent of respondents (vs 22.8% in pretest) admitted re-using one syringe for more than one patient. In conclusion, this study showed that a short course educational program may improve knowledge about HIV and partly change attitude, but can not change behaviour. Changing the practice of anesthesia health care workers needs continual education and appropriate training.

Cardiovascular and respiratory changes in laparoscopic cholecystectomy

Although laparoscopic cholecystectomy has several advantages over the traditional open cholecystectomy, it may however cause some adverse cardiovascular and respiratory effects associated with intraperitoneal insufflation of CO2. It is, therefore, recommended that appropriate hemodynamic and respiratory monitorings should be used routinely in order to prevent deleterious complications, especially in high risk patients.