Preventable in-hospital medical injury under the "no fault" system in New Zealand.

OBJECTIVES: To describe the pattern of preventable in-hospital medical injury under the "no fault" system and to assess the level of serious preventable patient harm. DESIGN: Cross sectional survey using a two stage retrospective assessment of medical records conducted by structured implicit review. SETTING: General hospitals with over 100 beds providing acute care in New Zealand. PARTICIPANTS: A sample of 6579 patients admitted in 1998 to 13 hospitals selected by stratified systematic list sample. MAIN OUTCOME MEASURES: Occurrence, preventability, and impact of adverse events. RESULTS: Over 5% of admissions were associated with a preventable in-hospital event, of which nearly half had an element of systems failure. The elderly, ethnic minority groups, and particular clinical areas were at higher risk. The chances of a patient experiencing a serious preventable adverse event subsequent to hospital admission were just under 1%, a figure close to published results from comparable studies under tort. On average, these events required an additional 4 weeks in hospital. System related issues of protocol use and development, communication, and organisation, as well as requirements for consultation and education, were pre-eminent. CONCLUSIONS: The risk of serious preventable in-hospital medical injury for patients in New Zealand, a well established "no fault" jurisdiction, is within the range reported in comparable investigations under tort.

Adverse events regional feasibility study: methodological results.

AIMS: To assess the feasibility of research into the occurrence, causation and prevention of adverse events (AEs) in New Zealand public hospitals. METHODS: A two-stage retrospective review was carried out on 1,575 medical records selected by systematic list sample from admissions for 1995 in three public hospitals in the Auckland region. Following initial screening, medical records were subject to structured implicit review using a standardised protocol. Feasibility measures, using international benchmarks where possible, were: adequacy of sample selection; completeness of medical records; reliability and validity of screener and reviewer judgements; internal consistency and face validity of AE determination and preventability assessment. RESULTS: The sample selection procedure was effective, although nearly 10% of records could not be secured. Information in medical records was sufficient for the identification and analysis of AEs. Adequate levels of agreement were achieved for screener and reviewer judgements, with kappa scores ranging between 0.302 and 0.622 and positive predictive values between 50.0% and 89.7%. The criteria for AE determination showed internal consistency and face validity, as did those for preventability. CONCLUSIONS: Research into the occurrence, causation and prevention of AEs in New Zealand health care settings is methodologically feasible and meets international benchmark standards.

Adverse events regional feasibility study: indicative findings.

AIMS: To identify substantive findings of potential clinical and managerial significance from a regional feasibility study of adverse events (AEs). METHODS: A standardised protocol using structured implicit review was applied to 142 AEs generated in an audit study of three public hospitals in the Auckland region for admissions in 1995. Areas of potential significance addressed were: timing, location and impact of AEs; preventability; and clinical context and predictability. RESULTS: 142 cases were identified as AEs (10.7% of 1,326 screened records). In 102 cases, 7.7% of all screened records, it was considered to be more likely than not that health care management contributed to the AE. About half the reported AEs occurred before the index admission, the majority outside hospital. Over half of all events resulted in disability that was resolved within a month. An average 6.7 extra days stay in hospital were attributable to AEs. For 60% of AEs the evidence for preventability was either low or nonexistent. Areas of potential prevention were predominantly educational. Over half of all AEs occurred in a surgical context. Medical AEs were more likely to have occurred outside hospital, to be drug-related, to be associated with an acute admission, to be classified as highly preventable, and to have a greater impact on hospital stay. CONCLUSIONS: Although the data generated by a feasibility study must be treated with caution, the pattern of results is consistent with comparable Australian findings and is of potential clinical and managerial significance.

Theophylline target concentration in severe airways obstruction - 10 or 20 mg/L? A randomised concentration-controlled trial.

The optimal serum concentration of theophylline for the management of acute airways obstruction was evaluated by comparing the response to target concentrations at the extremes of the usual therapeutic range. 174 patients requiring intravenous theophylline were randomly assigned to a target concentration of 10 or 20 mg/L. Control of theophylline dosage using measured theophylline concentrations and evaluation of efficacy and toxicity was performed under double-blind conditions. 87 patients (50%) required hospital admission. Of these, 54 patients (62%) were followed throughout their hospital admission and reviewed at an outpatient clinic approximately 1 week after discharge. The duration of hospital stay, and rate and extent of improvement in peak expiratory flow rate were not different between the groups. There was significantly more toxicity in the 20 mg/L group. The initial target concentration for theophylline in the management of acute airway obstruction should be 10 mg/L under circumstances where concentration is used to control theophylline dosages.

Alpha 1-acid glycoprotein concentrations and propranolol binding in elderly patients with acute illness.

Alpha 1-acid glycoprotein (AAG) concentrations and propranolol binding were investigated in the serum of elderly hospitalized patients with acute illness, and healthy elderly and young subjects. Significantly greater AAG concentrations and reduced unbound propranolol fraction were observed in the elderly with acute disease compared to the elderly controls. The greatest changes (up to five-fold) occurred with cancer, with lesser changes associated with myocardial infarction and ischaemic heart disease, acute infection, heart failure, chronic obstructive respiratory disease, and cerebrovascular accident. Various miscellaneous conditions were also associated with high AAG concentrations and enhanced propranolol binding. The healthy elderly had higher AAG concentrations and lower unbound propranolol fractions than the healthy young group. Overall there was a highly significant correlation between the propranolol binding ratio (bound/free) and the serum AAG concentration. These results suggest that the elderly population may be particularly susceptible to changes in AAG concentrations, and that during acute illness interpretation of serum concentrations of drugs which bind mainly to AAG, may require knowledge of their free fractions.

Bioavailability of metoprolol in young adults and the elderly, with additional studies on the effects of metoclopramide and probanthine.

The bioavailability of metoprolol was studied in eight healthy young and seven healthy elderly volunteers. Large interindividual differences in the bioavailability of metoprolol were observed in both groups. However, there was no significant difference in AUC, peak plasma concentration or elimination half-life between young and elderly, but time to peak concentration was significantly longer in the elderly. Pretreatment with metoclopramide had no effect on AUC but caused significant increases in peak concentration and decreases in time to peak concentration in both groups. Probanthine pretreatment (only to the young) resulted in a significant decrease in peak concentration of metoprolol and a significant increase in time to peak concentration but had no effect on the AUC. These results suggest that alterations in gastric emptying and gut motility due to ageing or other drugs have no effect on the overall availability of metoprolol to the systemic circulation but may have significant effects on the time to peak plasma concentration and peak concentration achieved after a single oral dose.

Sodium valproate (Epilim) in epilepsy: a trial.

Of thirty-five patients with various types of epilepsy treated with sodium valproate, 15 achieved complete seizure control on that drug alone, 12 other patients benefited and eight failed to improve on the drug. Excellent results were more likely in those with petit mal epilepsy and in those whose epilepsy was controlled with other drugs at the expense of side effects. Three patients were unable to tolerate valproate, but in general few patients experienced side effects and several patients felt much better on valproate than on their previous drugs. A twice daily dosage regime was satisfactory. Plasma valproate levels at the final dose covered a wide range, 0.21 - 1.2mmol/l (34 to 190 microgram/ml) and did not correlate with response, lack of response or side effects.

Metabolism of delta1-tetrahydrocannabinol by the isolated perfused dog lung. Comparison with in vitro liver metabolism.

The metabolism of (-)-delta1-tetrahydrocannabinol (delta1-THC) has been studied in the isolated perfused dog lung. After intravascular administration of [3H]-delta1-THC there was an overall biotransformation of 12%. Two major metabolites were isolated and identified as 3'-hydroxy-delta1-THC and 4'-hydroxy-delta1-THC. 7-Hydroxy-delta1-THC was also present together with small amounts of 6alpha-hydroxy-delta1-THC and 6beta-hydroxy-delta1-THC. An in vitro experiment using a dog liver microsomal preparation was also carried out and showed that the major metabolites were 6beta-hydroxy-delta1-THC and 6alpha-hydroxy-delta1-THC. 7-Hydroxy-delta1-THC and 1,2-epoxy-hexahydrocannabinol were also isolated together with small amounts of 3'-hydroxy-delta1-THC and 4'-hydroxy-delta1-THC. The side-chain hydroxylated compounds are hitherto undescribed metabolites of delta1-THC.