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J Tibballs

Publications and source records attributed to J Tibballs.

At least 19 recordsLinked to original sources
PubMed1992

Placebo-controlled trial of prednisolone in children intubated for croup.

Many studies have attempted to find out whether steroid treatment is beneficial in children with croup, but the results have been inconclusive. We have done a prospective placebo-controlled study of the effect of prednisolone on two clinical endpoints--the duration of intubation and the need for reintubation. Reasons for exclusion were age under 6 months, congenital airway anomalies, and previous intubation. 70 eligible children were randomly assigned treatment with prednisolone 1 mg/kg (n = 38) or placebo (n = 32) every 12 h given by nasogastric tube until 24 h after extubation. 11 (34%) placebo-treated and only 2 (5%) prednisolone-treated patients required reintubation after accidental or elective extubation (p = 0.004, Fisher's exact test; odds ratio 8.9, 95% confidence interval 1.7-59.3). Survival analysis with log-normal regression showed that the duration of intubation was shorter with steroid therapy (p less than 0.003) and increasing age (p less than 0.02), but was not influenced by endotracheal tube size or abnormality on chest radiograph. The median duration of intubation was 138 (95% CI 118-160) h in children who received placebo and 98 (85-113) h in the prednisolone group. Steroid therapy reduces the duration of intubation and the need for reintubation in children intubated for croup.

Age Factors↗
PubMed1992

Diagnosis and treatment of confirmed and suspected snake bite. Implications from an analysis of 46 paediatric cases.

OBJECTIVE: To identify reliable predictors of envenomation in suspected snake bite and to examine the current standard of treatment in envenomed patients. DESIGN: Retrospective cohort analysis of children presenting with suspected or confirmed snake bite in southern mainland Australia. Detection of snake venom in urine or blood was taken as proof of envenomation. SETTING: Intensive Care Unit, Royal Children's Hospital, Melbourne. PATIENTS: Forty-six children presenting between 1979 and 1990. MAIN OUTCOME MEASURES: Positive and negative clinical evidence, venom tests, and coagulation tests. RESULTS: Twenty-seven children (59%) had suspected bites; 10 (22%) were bitten but not envenomed; 9 (19%) were envenomed. Two died of coagulopathy. Headache, abdominal pain or vomiting were moderately predictive of envenomation (positive predictive values of 63%, 57% and 64% respectively). Coagulopathy was a highly sensitive, specific and reliably predictive (100%) indicator of envenomation. The pressure-immobilisation bandage was used in 28% of cases at the scene of the bite and in 41% on contact with medical or paramedical services. Twelve patients received antivenom; of these, six received adrenaline as premedication. CONCLUSION: Headache, abdominal pain, nausea or vomiting, or abnormal coagulation tests accurately predict envenomation by snakes in southern mainland Australia. More or better education on first aid and clinical management of snake bite is needed.

Adolescent↗
PubMed1992

Acute toxic reaction to carbamazepine: clinical effects and serum concentrations.

The clinical spectrum of toxic effects and serum concentrations after ingestion of carbamazepine were studied in 82 pediatric patients. Serum carbamazepine level was related to the depth of coma (p less than 0.001), convulsions (p = 0.002), hypotension (p less than 0.001), and the requirement for mechanical ventilation (p less than 0.001). In 10 patients in deep coma with a Glasgow Coma Scale (GCS) of 3-4, the mean serum level was 213 mumol/L (range 143 to 343); seizures, ventilatory failure, or hypotension caused by myocardial failure and conduction defects were observed. In four of these, large doses of inotropic agents were required, one patient was treated with plasmapheresis, and two died--one of cardiac failure and one of aspiration pneumonitis. In 27 patients with moderate coma (GCS 5-8), the mean serum level of carbamazepine was 112 mumol/L (range 63 to 176); convulsions were observed in two patients in this group. In 45 patients whose conscious state was mildly depressed or normal (GCS 9-15), the mean serum level was 73 mumol/L (range 37 to 128); additional effects were drowsiness (80%), ataxia (53%), nystagmus (38%), vomiting (17%), and dystonia (7%). I conclude that patients with serum carbamazepine levels of approximately 100 mumol/L require close observation, whereas those with levels greater than 150 mumol/L may require intensive life support.

Acute Disease↗
PubMed1992

Complications of endotracheal intubation and mechanical ventilation in infants and children.

OBJECTIVE: To assess the frequency of complications of endotracheal intubation and mechanical ventilation. DESIGN: Prospective cohort study. SETTING: Pediatric tertiary multidisciplinary ICU. PATIENTS: Eight hundred sixty-nine serial patients, of whom 500 were endotracheally intubated and 431 were mechanically ventilated. INTERVENTIONS: Daily clinical observation. MAIN OUTCOME MEASURES: Age, diagnosis, endotracheal tube size, type of ventilator and humidification, duration of intubation and mechanical ventilation, ventilatory settings, and complications (accidental extubation, tissue damage, endobronchial intubation, postintubation stridor, endotracheal tube blockage, pulmonary airleak, bronchopulmonary dysplasia, pulmonary atelectasis) were recorded. RESULTS: The median patient age was 10 months (25th and 75th quartiles: 1 month and 15 yrs). The median duration of endotracheal intubation and mechanical ventilation was 4 days and 2 days, respectively. A total of 186 complications were recorded in 119 (24%) patients. No deaths were due to intubation or ventilation. The overall frequency of accidental extubation was 3.2% of patients at a rate of 1.26 extubations/100 intubation days. In nonventilated, unsedated patients with croup or epiglottitis, the frequency of accidental extubation was 23% at a rate of 11.83 extubations/100 intubation days. Lung atelectasis occurred in 7.8%, airleak in 6.8%, and infection in 2.3% of patients. Other complications included tissue damage (3.4%), endobronchial intubation (2.4%), postintubation stridor (2.4%), bronchopulmonary dysplasia (2.3%), and endobronchial tube blockage (0.8%). CONCLUSIONS: Complications were related to the duration of intubation and mechanical ventilation.

Adolescent↗
PubMed1992

The cardiovascular and haematological effects of purified prothrombin activator from the common brown snake (Pseudonaja textilis) and their antagonism with heparin.

The cardiovascular and haematological effects of purified prothrombin activator derived from the venom of the Australian Common Brown Snake (Pseudonaja textilis) were studied in anaesthetised, mechanically ventilated dogs. Severe depression of systemic blood pressure and cardiac output and a rise in central venous pressure were observed. Thrombocytopenia, prolongation of both prothrombin time and activated partial thromboplastin time and a reduction in serum fibrinogen were also observed. All of these observed effects were prevented by the prior administration of heparin--a naturally occurring anticoagulant. We conclude that the prothrombin activator in Pseudonaja textilis venom may cause cardiovascular depression due to myocardial dysfunction secondary to disseminated intravascular coagulation.

Animals↗
PubMed1992

The efficacy of heparin in the treatment of common brown snake (Pseudonaja textilis) envenomation.

The efficacy of heparin therapy after subcutaneous injection of Common Brown Snake (Pseudonaja textilis) venom was studied in anaesthetised, mechanically ventilated dogs. Intravenous heparin (100 U/kg), administered fifteen minutes after envenomation, neither prevented nor hastened the recovery from cardiovascular depression and coagulopathy observed after venom administration. Heparin therapy is not recommended for the treatment of established human envenomation.

Animals↗
PubMed1992

Accuracy of the BoMED NCCOM3 bioimpedance cardiac output monitor during induced hypotension: an experimental study in dogs.

Changes in thoracic electrical bioimpedance during the cardiac cycle are utilised by the BoMed NCCOM3 monitor to measure cardiac output (COTEB). The technique provides a continuous noninvasive measurement but it has not been widely accepted. To determine the accuracy of the monitor, we compared its measurement with cardiac output measured by dye dilution (CODD) during induced hypotension and recovery in 23 dogs. After calibration of the NCCOM3 monitor during a resting state in each dog [mean blood pressure 112 +/- 17 (SD), mean CODD 3.22 +/- 0.99 l/min], the mean difference (COTEB-CODD) between paired measurements at the nadir of hypotension (blood pressure 55 +/- 24 mmHg) was 0.29 +/- 0.47 l/min whose limits of agreement (mean difference +/- 2 SD) were + 111.8% and -59.1% of the mean hypotensive CODD (1.10 +/- 0.66 l/min). Upon recovery from hypotension (mean blood pressure 102 +/- 20 mmHg), the mean difference between paired measurements was -0.28 +/- 0.66 l/min, whose limits of agreement were +44.1% and -67.8% of the mean CODD (2.36 +/- 1.01 l/min). The mean difference between the two techniques is too variable and excessive to permit substitution of one technique for the other. These results do not support the accuracy and reliability of the BoMed NCCOM3 cardiac output monitor.

Animals↗
PubMed1992

Endotracheal and intraosseous drug administration for paediatric CPR.

The endotracheal and intraosseous routes are alternatives to the intravenous route of access to the circulation during emergency resuscitation. Adrenaline, lignocaine and atropine are readily absorbed from the respiratory tract via an endotracheal tube. All drugs and resuscitative fluids can be infused into the tibial bone marrow using an intraosseous needle.

Administration, Inhalation↗
PubMed1991

Fatal cerebral haemorrhage after tiger snake (Notechis scutatus) envenomation.

OBJECTIVE: This case report illustrates the threat to life posed by tiger snake venom-induced coagulopathy, the importance of first-aid, precautions with antivenom administration, the dose of antivenom and the necessity to monitor the coagulation status. CASE SUMMARY: An 11-year-old child was envenomated several times by a tiger snake (Notechis scutatus). Despite administration of three ampoules (9000 units) of tiger snake antivenom, fatal cerebral haemorrhage occurred. Inadequate first-aid had been applied. The bite site was covered with a loose bandage instead of a pressure-immobilisation bandage. In hospital, facilities to monitor coagulation status were unavailable. CONCLUSIONS: More public education is required in first-aid management of snake envenomation. Frequent monitoring of coagulation status is necessary to optimise antivenom and coagulation factor therapy.

Blood Coagulation↗
PubMed1991

Studies on Australian snake venoms, Part II: The haematological effects of brown snake (Pseudonaja) species in the dog.

The haematological effects of Brown Snake (Pseudonaja) species (textilis, affinis, nuchalis) were studied in anaesthetised, mechanically ventilated dogs. Marked thrombocytopenia, depletion of serum fibrinogen and prolonged prothrombin and activated partial thromboplastin time, were recorded at 5 to 10 and 30 to 40 minutes after intravenous envenomation. Fibrin degradation products were not elevated. Because these haematological effects occurred simultaneously with cardiovascular depression (previously reported), we postulate that hypotension sometimes observed in human envenomation may be due to intravascular coagulation with myocardial ischaemia.

Animals↗
PubMed1991

Improving agreement between thoracic bioimpedance and dye dilution cardiac output estimation in children.

The measurement of thoracic electrical bioimpedance (TEB) offers a continuous, non-invasive method for monitoring cardiac output (CO). For clinical use, agreement with a current standard should be demonstrated. We describe a modification to the manufacturer's suggested data entry into the NCCOM3-R6 TEB monitor (BoMed Medical Manufacturing), which results in improved agreement with indocyanine green dye dilution (DD) CO estimation in paediatric patients. The manufacturer's instructions for the NCCOM3-R6 include an estimation of the volume of electrically participating thoracic tissue (VEPT) based on body weight. We also estimated the VEPT from direct anatomical measurement of thoracic length and circumference. The mean difference between paired DD and TEB CO using the manufacturer's weight-based instructions was 0.69 l/min with 95% confidence limits 2.34 to -0.96 l/min. The mean difference between the two CO techniques using our calculated VEPT was 0.35 l/min with 95% confidence limits 1.50 to -0.80 l/min. The linear regression correlation coefficient between the two techniques was 0.88 using VEPT estimated from the manufacturer's instructions and 0.94 using our calculated VEPT from measurement of thoracic dimensions. The range of DD CO was 0.41 to 8.35 l/min.

Adolescent↗
PubMed1991

The efficacy of antivenom in prevention of cardiovascular depression and coagulopathy induced by brown snake (Pseudonaja) species venom.

The efficacy of antivenom in prevention of cardiovascular depression and coagulopathy induced by Brown Snake species (Pseudonaja textilis, Pseudonaja affinis) was investigated in anaesthetised mechanically ventilated dogs. Venom and antivenom in variable amounts were incubated together at 37 degrees C for 30 minutes prior to intravenous injection. The dose of antivenom required to prevent severe cardiovascular depression and coagulopathy induced by Pseudonaja textilis venom was 25 times the current recommended dose for clinical use. A tenfold dose of antivenom was required to neutralise similar effects induced by Pseudonaja affinis venom. Large amounts of antivenom may be required in clinical use if coagulopathy or cardiovascular depression are present after envenomation by species of the Brown Snake genus.

Animals↗
PubMed1991

Diaphragmatic pacing: an alternative to long-term mechanical ventilation.

Electrical percutaneous stimulation of the phrenic nerves was first employed in 1948 by Sarnoff to provide temporary artificial ventilation in patients with respiratory failure. However, the technique was limited by development of infection around the electrode. Short-term radiofrequency stimulation of the phrenic nerves was first utilised by Glenn in 1964 and adapted to long-term use in patients with central hypoventilation in 1968 and with traumatic quadriplegia in 1972. The technique employed alternate pacing of each hemidiaphragm with high frequency stimulation (25-30 Hz) with a respiratory rate of 12 to 17 per minute which, in a series of 17 quadriplegic adults, although initially successful, was self-limiting because of eventual damage to the nerves and diaphragms. More recently, continuous bilateral simultaneous low frequency (up to 8 Hz) stimulation with a respiratory rate of 5 to 9 per minute has not induced myopathic changes. This phenomenon has been attributed to: 1. the conversion of the mixture of slow and fast twitch fibres in the diaphragm to a uniform population of fatigue resistant fibres induced by low frequency stimulation, and 2. the reduction in the total current necessary to achieve adequate gas exchange when both diaphragms contract simultaneously with the less frequent stimulation at lower energy. Diaphragmatic pacing has been applied to infants and children with emphasis on the selection of patients and optimum setting of stimulus parameters. This communication presents a case report of diaphragmatic pacing in a child with a review of the principles of application. The advantages and disadvantages compared to mechanical ventilation are also discussed.

Apnea↗
PubMed1990

Long-term outcome of children after intensive care.

To determine the long-term outcome of children admitted to a pediatric ICU (PICU), we studied 976 consecutive patients admitted to our PICU in the 12 months ending June 30, 1983, and evaluated their outcome 30 to 36 months after PICU admission. There was no relationship between duration of PICU admission and outcome. Young children were more likely to die than older children, but young children who survived did not have an increased risk of handicap. Of the 974 children available for follow-up, 20% died, 5% had a severe handicap, 2% had a moderate handicap, 12% had a mild handicap, 17% were functionally normal but required medical supervision, and 42% were normal. Thus, 80% of the children survived 30 months or more, and 91% of the survivors will probably lead an independent life.

Adolescent↗
PubMed1989

Ventilator-dependent children.

The issue of the ventilator-dependent child is a relatively-new one in Australia. Ventilator-dependent children pose complex and unique ethical, medical, economic and psychological problems. The experience of two Australian centres that are involved with the care of ventilator-dependent children is reported. Most of these children now are being cared for at home. Aspects of home care are outlined. After the initial period, the technical aspects are not a problem for most parents for whom the major issues are the provision and funding of nursing support. The complex ethical issues that are involved are discussed. It is concluded that undergoing ventilation at home rather than in a hospital appears to make the best of an otherwise almost-intolerable situation for ventilator-dependent children, but that much more information is required about the outcome for these children and the long-term psychosocial impact of this treatment.

Adolescent↗