Improving the medical management of organophosphorus pesticide poisoning through health services research and training

Abstract

Organophosphorus (OP) self-poisoning is a major global public health problem resulting in over 200,000 deaths each year with a case fatality of 15-30%. Early medical management consists of effective resuscitation and targeted antidote therapy.

This thesis argued that health services research and rural doctor training could be used to improve the medical management of OP poisoning in a resource limited rural Sri Lankan setting, where the delivery of critical care is limited by a lack of diagnostic tests and resuscitation skills. Research investigating the use of AChE in guiding clinical management, and research that measured the effectiveness of rural resuscitation training, were the two streams of research that were the founding pillars of the thesis. These two elements were linked together through a conceptual framework of knowledge translation, each operating at different points in the continuum of evidence being translated into practice.

An AChE POC test (Test-mate ChE) was demonstrated to provide accurate and reliable results in acute OP poisoning when compared with a reference laboratory. A survey based analysis of clinician’s knowledge, attitudes and practices found that most doctors valued the test, but also surprisingly found that doctors who were more experienced with AChE valued the test less. Low proportions valued the test in guidance of acute poisoning management (e.g. to direct oxime therapy and early discharge).

A systematic review highlighted a lack of supporting primary evidence for the use of AChE in relation to oxime use and discharge decisions. Advice on interpretation of AChE and caution about pitfalls in measurement were also lacking. These areas need to be addressed to optimise provision of AChE POC devices.

A train-the-trainer (TTT) model of resuscitation education was effective in improving resuscitation knowledge and skills in rural peripheral hospital doctors, and improvements in most components were sustained for 12 weeks. This demonstrated the effectiveness of using non-specialist doctors to conduct peer-led advanced life support (ALS) training in a low resource peripheral hospital setting, using objective knowledge and skills endpoints according to standardized metrics.

A systematic review of resuscitation of OP poisoning found no texts solely focused on acute initial management. An ‘OP specific’ ALS guideline was proposed based on consistent literature recommendations highlighting the importance of rapid atropinisation (doubling dose regimen) to be delivered simultaneous with immediate airway, breathing and circulation management. Other antidotes such as oximes should not be in the ALS guidelines.

A participatory action research approach was used to address practical problems through close engagement with health services and local training systems. The experience from both streams of research showed that such strategies were integral to the completion of the studies employed in the low resource rural setting. The thesis demonstrated health services research and training could be used to close the evidence-practice gap, and may have a role in the improvement of the medical management of OP poisoning. Future research should investigate clinical endpoints associated with the use of AChE in guiding OP poisoning management, the development of decision rules offering practical guidance in measurement and interpretation of AChE, the evaluation of OP specific ALS guidelines, and the sustainability rural resuscitation training programs.