The Clinical Outcomes and Physiotherapy Management of Patients with Organophosphate Poisoning: A Prospective Longitudinal Descriptive Study

Abstract

Background Organophosphates (OP) are pesticides or insecticides used worldwide, which may cause an acute cholinergic crisis and subsequent permanent disability or death (if not managed medically) after accidental or deliberate ingestion. The most clinically evident signs and symptoms of OP poisoning are respiratory depression, muscle weakness or paralysis, tachycardia, urinary incontinence, sweating, and abdominal pain with associated diarrhea. The clinical outcomes of patients diagnosed with OP poisoning in South Africa are confined to mortality and morbidity, and patients’ need for mechanical ventilation. Little is known about patients’ discharge destination and clinical course in the hospital. The physiotherapy management of patients diagnosed with OP poisoning in South Africa is under-researched. Existing evidence supports physiotherapists’ roles in the management of patients with critical illness as improving lung compliance and lung volume, clearing excessive retained secretions, optimizing oxygenation, recruiting collapsed alveoli, and assisting with early mobilisation (Stiller, 2013; Skinner et al., 2015). This study aims to describe the incidence of OP poisoning at the participating study site, to describe patients’ clinical course, as well as their physiotherapy management during hospitalisation at the study site in Gauteng province. Method A prospective, longitudinal, descriptive study was conducted over 18 months (October 2022 to March 2024) at the ICU of Thelle Mogoerane Regional Hospital (TMRH). Ethical clearance was obtained from the University of the Witwatersrand Human Research Ethics (Medical) (HREC) Committee (certificate nr. M211166). Permission to conduct the study was obtained from the TMRH physiotherapy department. Participants for the study had to be 18 years and older and not present with any preexisting respiratory pathology, physical disability, or cognitive impairment. Standard physiotherapy patient care provided was recorded by the clinician physiotherapists on the study- specific data collection form on days one to seven of the patient’s stay in ICU, and again on days 10, 14, and on the day of discharge from ICU. Data was captured on Excel and imported to IBM Statistical Package for the Social Sciences (SPSS) version 29 software for analysis. Descriptive and inferential analyses were performed, and testing was done at the p≤0.05 level of significance. Results During the 18-month study period, 655 patients were admitted to the TMRH ICU, of which 118 were diagnosed with OP poisoning (18%). The study included 56 eligible participants. There were more males (n=36; 64%) admitted than females (n=20; 36%), and most had intentionally ingested OP poison (n=36, 64%). It is noted that 68% (n=38) of the participants required mechanical ventilation iii with initial diagnosis. Patients received a median of 4 physiotherapy sessions delivered once daily during their ICU stay. The most common respiratory physiotherapy treatment techniques used on initial assessment were manual chest clearance techniques (n=33, 59%), suction (tracheal or oral) (n=37, 66%), positioning for ventilation-perfusion matching (n=19, 34%), and active cycle of breathing technique (n=10, 18%). Neuromusculoskeletal physiotherapy treatment techniques most used on day one of assessment and treatment were joint range of movement (n=33, 59%), sitting on the edge of the bed (n=9, 16%), sit to stand (n=10, 18%), marching on the spot (n=7, 13%) as well as assisted and independent mobility (n=4, 7% and n=7, 13% respectively). Upon participant discharge from the ICU, the median Peak Expiratory Flow (PEF) was 46% of predicted value, the median Medical Research Council Scale Sum Score (MRC-SS) of 42/60 (IQR: 36-48), and a median FSS-ICU score of 30.5/35 (IQR: 18-34). During physiotherapy sessions, no adverse events were noted. The only complication that developed was reintubation (n=5, 9%). This was necessary due to OP poisoning rebound (n=2; 4%), ventilator-associated pneumonia (n=1; 2%), and respiratory distress (n=1; 2%). For one participant, no reason for reintubation was recorded. Five participants demised (9%), and this was due to ventilator-associated pneumonia (n=1; 4%), cardiac arrest (n=1; 4%), and no reason recorded for 3 participants. A significant association (p=0.01) was found between the number of physiotherapy sessions received and the need for reintubation. No association was found between the final MRC-SS at discharge from hospital and the rate of reintubation (p=0.546). The study results found that participants had a median ICU length of stay of 7 (IQR: 4-11) days and a median hospital length of stay of 9 (IQR: 5-12) days. Sixty-eight percent of participants (n=38) were discharged home from, ICU, and none required outpatient physiotherapy follow-up services. Conclusion One-fifth of patients admitted to the TMRH ICU had OP poisoning, with a higher incidence in males. The hospital length of stay was longer than one week. All patients received physiotherapy while in the ICU. The need for reintubation was associated with the number of physiotherapy sessions received. A low mortality rate was observed, and patients were mostly discharged home.