Initial Laboratory Parameters and its Correlation to Intermediate Syndrome in Patients with Acute Organophosphate Poisoning

ABSTRACT

PURPOSE: The association of serial serum cholinesterase (SChE) activity and the occurrence of intermediate syndrome (IMS) in patients orally poisoned with organophosphate (OP) were investigated. In addition, other clinical and laboratory factors were assessed for their ability to predict the subsequent development of IMS. METHODS: A total of 114 patients presented to our emergency department with acute OP ingestion between 2007 and 2012 were enrolled in this prospective study. Of these patients, 67 who needed mechanical ventilation (MV) over five days were divided into the IMS group. The 47 patients weaned from MV within four days after admission, or who did not receive the assistance of MV, were placed in the non-IMS group. The level of SChE at admission, 48 hours, and 96 hours, at discharge after admission were checked. The APACHE II (Acute Physiology, Age, Chronic Health Evaluation II) score, the amount ingested, exposure route, gender, age, and the laboratory test results were collected. All statistical analyses were performed using the Statistical Package for the Social Sciences (version 20.0). RESULTS: The mean age of total enrolled patients was 53.7+/-17.9 years and 73 patients (64.0% of total patients) were male. There were 102(89.5%) patients who intentionally ingested the OP and the mean amount ingested was 102.5+/-64.9 mL. The mean time after patients sought medical care was 5.4+/-10.5 hours after ingestion. The level of SChE at admission was 1,586+/-796 U/L and the APACHE II score was 28.81+/-19.7. The arterial pH, bicarbonate and carbon dioxide pressure, and serum protein and albumin were significantly lower in the IMS group than the non-IMS group (p<0.001). In contrast, the serum amylase, lipase, and glucose were higher in the IMS group. The APACHE II score, serum albumin and amylase, arterial bicarbonate, and the SChE at 48 and 96 hours after ingestion were independent factors that predicted the occurrence of IMS in patients with OP poisoning. The rate of recovery was 86.6% in the IMS group and 100% in the non-IMS group (p<0.001). CONCLUSION: Patients with a higher APACHE II score and levels of serum amylase, and lower levels of serum albumin and arterial bicarbonate, may be associated with the occurrence of IMS. Furthermore, when SChE levels after 48 hours and 96 hours did not increase, compared with the level of SChE at admission, patients tended to show IMS.