Platelet Function in ITP, Independent of Platelet Count, Is Consistent Over Time and Is Associated with Both Current and Subsequent Bleeding Severity.

BACKGROUND: Treatment decisions for patients with immune thrombocytopenia (ITP) are difficult because patients with similarly low platelet counts differ in their bleeding tendency. We recently reported that platelet function tests, independent of platelet count, are associated with concurrent bleeding severity, suggesting that these tests may be useful indicators of future bleeding in ITP. OBJECTIVES: To test this hypothesis, we evaluated the consistency of these platelet function tests over time and their association with subsequent bleeding severity. METHODS: Bleeding score and platelet biomarkers were evaluated in a cross-sectional study of children with ITP at two visits separated by a median of 10 months. RESULTS AND CONCLUSIONS: Correlations between Visit 1 and Visit 2 results for immature platelet fraction, circulating and agonist-stimulated platelet surface P-selectin, and activated GPIIb-IIIa and GPIbα indicated consistency of the platelet phenotype over time. Consistent with our previous findings, platelet biomarkers at each visit were significantly associated with the concurrent bleeding score. Furthermore, increased P-selectin on circulating platelets and reduced agonist-stimulated P-selectin and activated GPIIb-IIIa-positive platelets at Visit 1 were significantly associated with bleeding scores at Visit 2 and remained significantly associated with bleeding severity after adjustment for platelet count. These results suggest a mechanistic link between desensitization of agonist receptors and increased bleeding severity. In summary, platelet function in ITP, independent of platelet count, is consistent over time and is associated with both concurrent and subsequent bleeding severity. These findings support further evaluation of platelet function testing to help guide patient management in ITP.

An audit of the haemodynamic and emergence characteristics of single-shot 'ketofol'.

'ketofol', the single-syringe combination of ketamine and propofol (50 mg of ketamine and 90 mg of propofol in a 10 ml syringe) is becoming increasingly popular for short procedures, progressively replacing the more traditional use of ketamine and diazepam in some settings. This audit examined the haemodynamic, emergence and other characteristics of ketofol administration in 42, otherwise fit, women undergoing bilateral post-partum tubal ligation at Vila Central Hospital in Vanuatu. The combination of ketamine and propofol had no clinically important adverse haemodynamic effects. Wake-up from ketofol was favourable, with low rates of nausea and minimal emergence delirium. However, 43% of patients required airway support. For short procedures such as post-partum tubal ligation in fit patients, ketofol appears to have minimal adverse haemodynamic effects and favourable emergence characteristics.

Intensive care in paradise--a review of 57 ventilated patients in ICU in Vanuatu over five years.

Intensive care is not a medical priority for developing nations. Vila Central Hospital is the major referral centre for the developing Pacific island nation of Vanuatu and runs an 'as-needed' intensive care service. Between January 1999 and January 2004, fifty-seven patients were ventilated at Vila Central Hospital. Twenty-two patients survived and 35 died. Eleven patients were declared brain dead, eight died from renal failure, six from overwhelming respiratory failure, three from sepsis, four due to equipment or technical failure, two of unknown causes and one died after transfer to Australia. The patient age range extended from newborns to 80 years. Survivors were ventilated for durations of four hours, (postoperative), to 14.5 days, (ARDS), the median being two days.

Perinatal mortality 1982-2001 at Vila Central Hospital, Vanuatu.

OBJECTIVE: To determine the perinatal mortality at Vila Central Hospital (VCH) and thereby make an estimate of Vanuatu's perinatal mortality. METHODS: Labour floor and nursery records from VCH, Vanuatu's only tertiary referral hospital, were examined and collated for the period 1982-2001. Death certificate books were also examined. The perinatal mortality rate was calculated as the sum of stillbirths (infants = 20 weeks and/or = 500 g) and neonatal mortality (deaths <28 days). Premature infants were recorded for infants less than 37 weeks gestation and small-for-gestational-age for infants less than 2500 g. RESULTS: The mean perinatal mortality rate for the period was 27/1000, (range 15-36/1000). The mean stillbirth rate was 15/1000, (range 8-22/1000). The neonatal mortality was 12/1000, (range 4-18/1000). Premature babies accounted for 37/1000 births, (range 11-80/1000). Small-for-gestational-age infants were recorded in 45/1000 births, (range 16-83/1000). The mean twinning rate was 12/1000. Seven spontaneous triplets, two quadruplets and two pairs of siamese twins were born. Sepsis, meconium aspiration and birth asphyxia were the commonest causes of neonatal death. CONCLUSION: Accurate data collection is difficult in Vanuatu. There is the risk of under-ascertainment however, the figure of 27/1000 represents the current best possible estimate of perinatal mortality at VCH over the last 20 years. VCH is Vanuatu's premier hospital and it is likely that the national figure for perinatal mortality is higher, probably in the range of 37-39/1000. This places Vanuatu's perinatal mortality at a level 30 years or more behind Australia. These figures represent the largest account of hospital based perinatal data collected from any Pacific island nation.

The effect of variable-dose diazepam on dreaming and emergence phenomena in 400 cases of ketamine-fentanyl anaesthesia.

This randomised double-blind field study compared 400 anaesthetics using diazepam (0, 0.025, 0.5, 0.1, 0.175 mg.kg-1) with ketamine (1 mg.kg-1) and fentanyl (1 microg.kg-1) in Melanesian patients. Dreams were very common and generally positive in nature. A minimum of 0.1 mg.kg-1 of diazepam was needed to significantly reduce dreaming when compared with water (67.5% vs. 94.6%; p < 0.0001), and to significantly lower median (95% CI) emergence delirium scores (4 (3-4) vs. 6 (5-7)). Gender and age did not affect the rate of dreaming. Increasing the dose of diazepam did not improve the dream experience. Patient satisfaction scores were similar between groups. Increases in blood pressure and heart rate were greater in dreamers than in non-dreamers. All groups had high rate-pressure products but this was highest when diazepam was not used. Higher diazepam doses significantly reduced the increase in blood pressure and heart rate at 3 and 6 min postketamine. When used with ketamine and fentanyl, 0.1 mg.kg-1 of diazepam has favourable psychic and cardiovascular effects. Lower diazepam doses generally had little effect whereas larger doses did not enhance the benefits further.

Ivermectin is better than benzyl benzoate for childhood scabies in developing countries.

OBJECTIVE: To compare single dose oral ivermectin with topical benzyl benzoate for the treatment of paediatric scabies. METHODS: An observer-blinded randomized controlled trial was undertaken at Vila Central Hospital, Vanuatu. One hundred and ten children aged from 6 months to 14 years were randomized to receive either ivermectin 200 micro g/kg orally or 10% benzyl benzoate topically. Follow up was at 3 weeks post-treatment. Primary outcome measures were the number of scabies lesions, the itch visual analogue score and nocturnal itch. Secondary outcome measures were the skin's reaction to treatment, the passage of worms in stool and other side effects. RESULTS: Eighty patients completed the study protocol. There was no significant difference between the two treatments; both produced a significant decrease in the number of scabies lesions seen at follow up. Ivermectin cured 24 out of 43 patients (56%), and benzyl benzoate 19 out of 37 patients (51%) at 3 weeks post-treatment. No serious side effects were noted with either treatment, but benzyl benzoate was more likely to produce local skin reactions (P = 0.004, OR 6.4, 95% CI 1.6-25.0) CONCLUSIONS: Ivermectin is cheap and effective in the treatment of paediatric scabies. Ivermectin has minimal observed toxicity and has the additional beneficial effects of antiparasitic action in onchocerciasis, filariasis and strongyloidiasis. Ivermectin is better than benzyl benzoate for the treatment of paediatric scabies in developing countries.

Spontaneous respiration via an open trachea for resection of a high tracheal stenosis in a child.

The successful management of tracheal stenosis requires compromise between the competing interests of the surgical and anaesthetic teams and the resources available. A seven-year-old girl with marked tracheal stenosis was successfully managed spontaneously breathing via an open trachea and a laryngeal mask. Anaesthesia was maintained by propofol infusion. When the trachea was opened, supplemental oxygen was administered via a modified cholangiocatheter placed into the distal segment. At no point was the trachea intubated.

A randomized comparison of low-dose ketamine and lignocaine infiltration with ketamine-diazepam anaesthesia for post partum tubal ligation in Vanuatu.

Ketamine remains one of the most commonly used anaesthetic agents around the world. Despite it being the anaesthetic agent of choice in many developing nations, there is a paucity of literature describing ketamine in the developing world. In what we believe is the first randomized controlled trial to be performed in Vanuatu (formerly the New Hebrides) we compared the use of ketamine 0.9 mg/kg and diazepam 0.07 mg/kg with ketamine 0.3 mg/kg and 2% lignocaine infiltration in 50 Melanesian women undergoing post partum tubal ligation. All women received 0.5 mg/kg intramuscular pethidine. Visual analog pain scores and verbal numeric satisfaction scores were similar between the groups. However the time to obeyed command was significantly faster in the 0.3 mg/kg ketamine group (7.0+/-4.9 vs 13.0+/-9.2 min). The incidence of dreaming was similar and the content rated as pleasant by both groups. In institutions where post-anaesthesia care resources are limited, 0.3 mg/kg ketamine with local anaesthesia provides for earlier self-care of patients after tubal ligation, without compromise of analgesia, emergence or satisfaction. The implications of these findings extend to other procedures that require short general anaesthesia, which can be adequately performed with low-dose ketamine and local anaesthesia. The latter technique allows more rapid awakening.

Urine drug screens in overdose patients do not contribute to immediate clinical management.

A prospective study assessed whether routine urine drug screens might alter the management of overdose patients. Urine was collected from 107 patients with a diagnosis of deliberate self-poisoning seen in the emergency department (ED) of a teaching hospital. The mean age of patients was 36 years (range 13-86 years) and 64% were female. All patients recovered after standard investigations and management, which did not include knowledge of urinary drug screen results. Two hundred ninety-seven compounds were detected in the 107 urine samples. Twenty percent were drugs administered in the ED. Sixty-five percent of patients were found to have taken more than one drug. Benzodiazepines were detected in 18% of samples, paracetamol in 10%, and alcohol in 8%. Sixty-one drugs, in 35 people, were identified that the patients did not report taking. Of these, paracetamol (10), benzodiazepines (9), and tetrahydrocannabinol (8) were the most common. All patients in whom paracetamol was found had already had paracetamol detected in blood and appropriate management instituted. If the results of urine screening had been immediately available this would not have affected the management or outcome of any patient.

Effects of diclofenac in the rat tail ischaemia--reperfusion injury model of acute hyperalgesia.

The rat tail ischaemia--reperfusion model of acute hyperalgesia described by Gelgor et al. (Pain 24 (1986) 251) has been investigated pharmacologically and electrophysiologically. Despite the advantages of this reusable animal model, biochemical changes associated with the behavioural response have not been determined. After injury+/-subcutaneous diclofenac pretreatment, we investigated the behavioural response (changes to thermally-induced tail flick latency) and measured diclofenac, prostaglandin E(2), 6-keto-prostaglandin F(1 alpha) and thromboxane B(2) concentrations in the tail, spinal cord and brain. Subcutaneous injection of 40 mg kg(-1) diclofenac sodium abolished the hyperalgesic response, suppressed the increased eicosanoid production in the tail, inhibited eicosanoid synthesis in the brain, but gave equivocal effects on eicosanoid concentrations in the spinal cord. Injection of 10 and 20 mg kg(-1) diclofenac reduced the duration of hyperalgesia but did not abolish the behavioural response. Diclofenac concentrations in all three tissues were similar, being approximately 5--10% of the corresponding plasma concentrations. We propose that both central and peripheral mechanisms are associated with the hyperalgesia and that the findings lend indirect support to a central action for non-steroidal anti-inflammatory drugs.

Caesarean section in a patient with paramyotonia congenita.

This case report details spinal anaesthesia for an elective caesarean section in a patient with the rare condition of paramyotonia congenita. There are few case reports of anaesthesia in this condition and none in the Australian anaesthetic literature. This case highlights the need for the avoidance of hypothermia and depolarizing muscle relaxants, the safety of spinal anaesthesia and a conservative approach to the management of plasma potassium concentration. The subsequent review outlines the current literature and discusses other issues involved in the anaesthetic management of this disorder.

Preoperative dextromethorphan reduces intraoperative but not postoperative morphine requirements after laparotomy.

UNLABELLED: N-methyl-D-aspartate (NMDA) antagonists combined with opioids are thought to be effective in the control of pain states. We evaluated morphine use and analgesia in 37 patients postlaparotomy. Patients received 60 mg of oral dextromethorphan or placebo the night before and again 1 h before surgery. Morphine was titrated intraoperatively to maintain blood pressure and heart rate within 20% of baseline and postoperatively via patient-controlled analgesia (PCA). The dextromethorphan and placebo groups were compared for morphine use intraoperatively, in recovery, via PCA in the first 4 and 24 h, and total use over the study period. Pain scores at rest and on activity for the first 4 and 24 h were also compared. Intraoperatively, the dextromethorphan group required less morphine: 13.1+/-4.3 vs 17.6+/-6.0 mg (P = 0.012). Postoperatively, there was no significant difference between the dextromethorphan and placebo groups for morphine use: in the recovery room 10.9+/-7.7 vs 12.1+/-7.7 mg; the first 4 h of PCA 15.9+/-9.3 vs 12.7+/-5.1 mg; the first 24 h of PCA 76.4+/-44.7 vs 61.8+/-27.5 mg; or in total morphine use 100.4+/-49.5 vs 91.5+/-3.1 mg. Pain scores for the two groups were not statistically different throughout the study period. We conclude that 60 mg of oral dextromethorphan given the night before and repeated an hour before surgery does not provide a postoperative morphine-sparing effect or improve analgesia after laparotomy. IMPLICATIONS: Patients given dextromethorphan before surgery had significantly reduced intraoperative morphine requirements. However, postoperative morphine requirements were unaltered. Dextromethorphan may need to be continued postoperatively to improve postoperative analgesia.

Benztropine abuse and overdose--case report and review.

The abuse and overdose of anti-cholinergic agents such as benztropine is well reported in the psychiatric and emergency medicine journals. However, despite almost 40 years since the first modern report, physicians in general remain poorly aware of anti-cholinergic abuse. A case report of recreational overdose of benztropine in a 19 year old schizophrenic patient is presented. Delirium and anti-cholinergic manifestations persisted for five days necessitating prolonged hospitalization. The literature on benztropine abuse and overdose is reviewed.

Pulse oximetry. Gold standard or false sense of security?

OBJECTIVE: To provide a concise review of the history, technology, theory, limitations and outcomes of pulse oximetry. DATA SOURCES AND SELECTION: Articles published in major medical journals since 1985 critically appraising pulse oximetry were reviewed, as were numerous historical papers. RESULT: The pulse oximeter is an imperfect device, with numerous potential limitations. CONCLUSION: The pulse oximeter is reasonably accurate under most conditions. However, its reliability diminishes as the clinical situation deviates from the norm, possibly when accuracy is most needed.