For Health Professionals - Poisons Information Centre
The purpose of this page is to provide a set of resources that can assist with the management of a poisoned patient.
These resources however, do not replace calling the Queensland Poisons Information Centre on 13 11 26 for advice.
The general approach to poisoning
F F S Daly, M Little & L Murray.
A risk assessment based approach to the management of acute poisoning.:Emergency Medical Journal
, [Online] 2006, vol.23, pp.396-399
Available from Internet: http://emj.bmj.com/content/23/5/396.full.pdf
The QT Nomogram
- The QT Nomogram aims to risk stratify patients for the development of torsades de pointes (TdP) by plotting the absolute (or uncorrected) QT versus heart rate (HR). By not correcting the QT interval it overcomes the limitations inherent in the use of formulas that attempt to correct the QT interval for heart rate (e.g. Bazett's formula which most ECG machines use). Bazett's formula overcorrects the QT interval when the HR is >70 resulting in an abnormally elevated QT. If the value is above the nomogram line then the patient is at risk of developing TdP. These patients should be cardiac monitored until their QT- HR pair is below the line on the nomogram.
Evidence for the use of the QT nomogram comes from a study by Chan et al which systematically reviewed cases of drug-induced TdP in the literature compared with a data set of (control) patients taking non cardiotoxic drugs (paracetamol, diazepam, oxazepam, temazepam) in overdose. In this study only 4 (1%) of 318 of the control patients had a QT- HR pair above the line, and only 2 (1.5%) of 129 cases of drug-induced TdP were below the line. Sensitivity and specificity for the QT nomogram was superior to using either a cut of QTc of 450 or 500msec. Consideration must be given to the dotted line region as this area is not well defined in regards to risk of TdP. However, most cases of TdP occur when the HR is between 40-80 beats/minute and tachycardia is seldom associated with TdP due to a proposed protective effect.
Guidelines for the management of paracetamol poisoning in Australia and New Zealand
Pathway for the management of snake bites
- The suggested clinical pathway for observation and blood testing of patients with suspected snakebite has been developed by the investigators of the Australian Snakebite Project as part of the study entitled "Changes in serial laboratory test results in snakebite patients: when can we safely exclude envenoming?" In a series of snakebite patients, the combination of three laboratory tests (INR, aPTT and CK) together with repeated neurological examinations, detected all but two cases (isolated myotoxicity) of severe envenoming within 12 hours. In these 2 cases, bloods were taken early (within 4 hours) and then again not until 20+ hours post bite. It is likely that both patient's CKs would have been elevated by 12 hours. The results of the study therefore support an observation period of 12 hours for suspected snake bite, with repeated laboratory and neurological assessments performed on admission and at 6 hours and 12 hours after the bite.