A previous history of acute intermittent porphyria as a complication of obstetric anaesthesia

[Obstetrical anaesthesia and porphyrias]

Acute hepatic porphyrias are genetic diseases, characterized by acute neurological symptoms, sometimes fatal, triggered by different factors, in particular by many anaesthetic drugs, and also by pregnancy. We report here the experience of three porphyric patients'deliveries, allowing us to consider a proposition of management in this context. After discussion between anaesthesiologist, obstetrician and porphyria specialist, two types of management of such patients can be foresee. Asymptomatic patients, or in long remission, can benefit from locoregional anesthesia techniques with bupivacaine for both labour analgesia and Caesarean section. Spinal anaesthesia is then the technique of choice, allowing using smaller quantity of local anaesthetic than epidural anaesthesia. For symptomatic patients, or in crisis, we have rather choose intravenous narcotics for labour analgesia, and general anaesthesia for Caesarean section. The hypnotic agent of choice for both induction and maintenance of such anaesthesia is then propofol.

Randomized, double-blinded comparison of tropisetron and placebo for prevention of postoperative nausea and vomiting after supratentorial craniotomy

This prospective, randomized, placebo-controlled, double-blinded study was designed to evaluate the efficacy of tropisetron in preventing postoperative nausea and vomiting after elective supratentorial craniotomy in adult patients. We studied 65 ASA physical status I-III patients aged 18 to 76 years who were undergoing elective craniotomy for resection of various supratentorial tumors. Patients were divided into two groups and received either 2 mg of tropisetron (group T) or saline placebo (group P) intravenously at the time of dural closure. A standard general anesthetic technique was used. Episodes of nausea and vomiting and the need for rescue antiemetic medication were recorded during 24 hours postoperatively. Demographic data, duration of surgery and anesthesia, and sedation scores were comparable in both groups. Nausea occurred in 30% of group T patients and in 46.7% of group P patients (P >.05). The incidence of emetic episodes was 26.7% and 56.7% in the two groups (P <.05). Rescue antiemetic medication was needed in 26.7% and 60% of the patients (P <.05). Administration of a single dose of tropisetron (2 mg intravenously) given at the time of dural closure was effective in reducing postoperative nausea and vomiting after elective craniotomy for supratentorial tumor resection in adult patients.

Effect of prophylactic ondansetron on postoperative nausea and vomiting after elective craniotomy

This prospective, randomized, placebo-controlled, double-blind study was designed to evaluate the efficacy of ondansetron, a 5-HT3 antagonist, in preventing postoperative nausea and vomiting (PONV) after elective craniotomy in adult patients. The authors also tried to discover certain predictors for postcraniotomy nausea and vomiting. We studied 170 ASA physical status I and II patients, aged 15 to 70 years, undergoing elective craniotomy for resecting various intracranial tumors and vascular lesions. A standardized anesthesia technique and postoperative analgesia were used for all patients. Patients were divided into two groups and received either saline placebo (Group 1) or ondansetron 4 mg (Group 2) intravenously at the time of dural closure. Patients were extubated at the end of surgery and episodes of nausea and vomiting were noted for 24 hours postoperatively in the neurosurgical intensive care unit. Demographic data, duration of surgery, and anesthesia and analgesic requirements were comparable in both groups. Overall, a 24-hour incidence of postoperative emesis was significantly reduced in patients who received ondansetron compared with those who received a saline placebo (39% in Group 1 and 11% in Group 2, P = .001). There was a significant reduction in the frequency of emetic episodes and rescue antiemetic requirement in patients treated with ondansetron; however, ondansetron did not significantly reduce the incidence of nausea alone (14% in Group 2 vs 5% in Group 1, P = .065). Prophylactic ondansetron had a favorable influence on PONV outcome measures such as patient satisfaction and number needed to prevent emesis (3.5). Side effects were similar in both groups. We conclude that ondansetron 4 mg given at the time of dural closure is safe and effective in preventing emetic episodes after elective craniotomy in adult patients.

A randomized controlled trial of the antiemetic effect of three doses of ondansetron after strabismus surgery in children

METHODS

One hundred and thirty-one healthy children, aged 31-152 months, undergoing strabismus surgery under general anaesthesia, were randomly allocated to one of four groups: group A received 0.04 mg.kg-1 ( identical with 1 mg.m-2) of ondansetron, group B 0.1 mg.kg-1 ( identical with 2.5 mg.m-2), group C 0.2 mg.kg-1 ( identical with 5 mg.m-2) and group D placebo, given intravenously following induction of anaesthesia. Morphine 0.15 mg.kg-1 was given intravenously, intraoperatively, to provide postoperative analgesia. Hourly records of emetic episodes were made for 24 h.

RESULTS

A considerably higher proportion of children suffered emesis in the placebo group compared to the active treatment groups taken together, during the first 8 h of postoperative care (76% vs. 45%, P=0.002). During the first 8 h, only 25% of those in treatment group C suffered emesis, the number-needed-to-treat was 3. There was a statistically significant decrease in the chance of vomiting with increasing dose of ondansetron (P=0.03). By 24 h, the difference in the rate of emesis was less marked but still statistically significant (90% vs. 69%, P=0.03).

CONCLUSION

Overall, children given ondansetron had less than one-half the risk of vomiting compared to those given placebo (hazard ratio 0.46, 95% confidence interval 0.29-0.74). The mean number of emetic episodes declined from 2.73 in the placebo group to 1.92 in treatment group C. There was no difference in the incidence of side-effects between groups.

Acupressure treatment for prevention of postoperative nausea and vomiting

Postoperative nausea and vomiting are still common problems after general anesthesia, especially in ambulatory surgery. Drug therapy is often complicated with central nervous system symptoms. We studied a nonpharmacological method of therapy--acupressure--at the Pericardium 6 (P.6) (Nei-Guan) meridian point. Two hundred consecutive healthy patients undergoing a variety of short surgical procedures were included in a randomized, double-blind study: 108 patients were in the acupressure group (Group 1) and 92 patients were in the control group (Group 2). Spherical beads of acupressure bands were placed at the P.6 points in the anterior surface of both forearms in Group 1 patients, while in Group 2 they were placed inappropriately on the posterior surface. The acupressure bands were placed before induction of anesthesia and were removed 6 h postoperatively. They were covered with a soft cotton wrapping to conceal them from the blinded observer who evaluated the patients for presence of nausea and vomiting and checked the order sheet for any antiemetics prescribed. In both groups, the age, gender, height, weight, and type and duration of surgical procedures were all comparable without significant statistical difference. In Group 1, only 25 of 108 patients (23%) had nausea and vomiting as compared to Group 2, in which 38 of 92 patients (41%) had nausea and vomiting (P = 0.0058). We concluded that acupressure at the P.6 (Nei-Guan) point is an effective prophylaxis for postsurgical nausea and vomiting and therefore a good alternative to conventional antiemetic treatment.

The management of a dental abscess in a patient with acute intermittent porphyria. A case report

The case of a 40-year-old white woman with a periapical abscess of pulpal origin and the medical condition of acute intermittent porphyria is described. The oral and dental management of the case with reference to complications, etiology, and symptoms of acute intermittent porphyria is reviewed.

[Anesthesia and hepatic porphyria]

Three of the acute hepatic porphyrias, acute intermittent porphyria, variegata porphyria and hereditary coproporphyria, are characterized by an idiosyncratic reaction to many common drugs; the resulting excessive excretion of porphyrin precursors is responsible for episodes of acute neurological dysfunction. This review aimed to focus the attention of the anaesthesiologist on the porphyrinogenic properties of all the drugs used in anaesthesia and intensive care. An outline of the chemistry of porphyrins and the enzymatic pathways were recalled, so as to place the acute porphyrias in their proper perspective. There follows a reminder of the clinical aspect of acute porphyric crises. The part played by drugs is then assessed from clinical and laboratory data concerning their porphyrinogenicity. Those drugs for which there is conflicting evidence regarding their safe use in porphyric patients are discussed: propofol, ketamine, benzodiazepines, etomidate, local anaesthetics. Recommendations supported by clinical and experimental data are given, especially the results obtained with the chick embryo liver model. Treatment of the acute crisis is provided, with particular emphasis on the use of haematin. The anaesthetic management of hepatic porphyric patients is described. Those drugs which are well-known porphyrinogenic compounds in the chick embryo liver must be excluded from use for anaesthesia in the porphyric patients, even if they have been observed to be innocuous in rare cases of asymptomatic patients. Finally, recommendations for anaesthesia in symptomatic cutanea porphyria are given.

Physical assessment and differential diagnosis of the poisoned patient

The rapid diagnosis and immediate intervention required in patients with serious drug overdose or poisoning makes toxicological screening of limited value to the emergency department physician. Instead, a careful clinical evaluation using the history, physical examination, and the more readily available laboratory tests may allow a tentative diagnosis and the initiation of life-saving treatment. Laboratory tests should include serum osmolality, electrolytes, glucose, BUN and an estimation of the anion and osmolar gaps. The ECG can also provide useful information. Clinical findings of important include altered blood pressure, pulse, respiration and body temperature, the presence of coma, agitation, delirium or psychosis, and muscular weakness. An ophthalmological examination is also of importance in the acutely poisoned patient. Oral burns or dysphagia may occur following ingestion of any strongly reactive substance, but the absence of oral burns does not preclude the possibility of oesophageal or stomach injury. Odours and skin colour may also contribute to the diagnosis. Comprehensive toxicology screening may not be immediately available, or may be inaccurate, thus adding little to the information obtained during the initial evaluation of the poisoned patient.

Primate model of parkinsonism: selective lesion of nigrostriatal neurons by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine produces an extrapyramidal syndrome in rhesus monkeys

Systemic administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to rhesus monkeys (1.0-2.5 mg/kg i.v.) produces irreversible damage to nigrostriatal neurons. Dopaminergic neurons in the dorsolateral part of striatum were the most vulnerable. The major clinical signs of an extrapyramidal syndrome, but not resting tremor, appeared only in MPTP-treated monkeys suffering from more than 80% reduction in striatal dopamine. No chronic changes in the mesolimbic dopaminergic system were observed. Immunocytochemical staining of the mid-brain with a tyrosine hydroxylase antiserum indicated that MPTP produced a significant decrease of dopaminergic cell bodies in the A9, but not in the A10 ventrotegmental area. Despite greater than 80% decrease in A9 nigral cell bodies, the dopamine content decreased only by 50%. Sprouting of the surviving nigral A9 neurons was observed histologically and neurochemically in the area above substantia nigra. The present behavioral, neurochemical and histological results indicate that MPTP produces an ideal primate model for studying parkinsonism. Selective lesion of more than 80% of the nigrostrial neurons by MPTP is sufficient to produce the major clinical signs of the extrapyramidal syndrome in idiopathic parkinsonism.

Effect of low dose droperidol on postoperative vomiting in children

This double-blind study assessed the effect of low dose droperidol (0.005 mg x kg-1) on the incidence of postoperative vomiting in 200 children in ASA classification I and II, ranging from one to 15 years of age. The results showed that the dose of droperidol used in this study was very effective in reducing vomiting in children 11 to 15 years of age. The duration of stay in the post-anaesthetic care unit was not prolonged and no extrapyramidal symptoms related to the drug were observed. In our opinion the administration of droperidol 0.005 mg x kg-1 before the end of the operation will reduce the possibility of vomiting within 24 hours of operation in children in 11-15 year age group who are expected to have a high incidence of postoperative vomiting.