Abstract:Objective To study the predictor indexes for requirement of mechanical ventilation in patients of acute organophosphate poisoning (AOPP) in early stage, in order to improve the success rate of rescue. Methods Fifty-eight patients with AOPP from July 2012 to December 2014 were retrospectively studied. According to the line whether mechanical ventilation treatment was needed in 24 hours or not, the patients were divided into two groups: the mechanical ventilation group and non-mechanical ventilation group. The average arterial pressure (Map) and arterial blood lactic acid (Lac) on admission, and Lac, central venous oxygen saturation (ScvO2), standard base excess (SBE), remaining acetylcholinesterase (AChE), arterial oxygen saturation (SaO2), arterial blood oxygen partial pressure (PaO2), arterial blood CO2 partial pressure (PaCO2), inspired oxygen fraction (FiO2) 6 hours after admission were detected. PaO2/FiO2 and 6-hour lactate clearance rate, poisoning severity score (PSS) and acute physiology and chronic health evaluation system Ⅱ (APACHE Ⅱ) score were calculated. The differences in the various indicators were compared between the two groups, and their correlations with mechanical ventilation were analyzed. The prediction ability of mechanical ventilation of relevant indexes was observed and their advantages were compared. Results The APACHE II score and PSS score of the mechanical ventilation group were higher than those of the non-mechanical ventilation group with significant differences (P < 0.05). SBE, AchE, SaO2, PaO2 and PaO2/FiO2 of the mechanical ventilation group were significantly lower than those of the non-mechanical ventilation group (P < 0.05). The age, sex, Map, Lac, 6 h-LCR, ScvO2 and PaCO2 of both groups were of no significant differences (P > 0.05). Mechanical ventilation was obviously correlated to the APACHE Ⅱ score, PSS score, SBE, AchE, SaO2, PaO2, PaO2/FiO2 and P (A-a) O2 (r = 0.661, 0.647, -0.396, -0.371, -0.367, -0.504, -0.684, 0.439; P < 0.05). Concerning the ability to predict the need for mechanical ventilation, the AUC of APACHE Ⅱ, PSS, P (A-a) O2, SBE, AChE, SaO2, PaO2 and PaO2/FiO2 AUC was 0.883, 0.885, 0.772, 0.742, 0.731, 0.759, 0.801 and 0.927 respectively. Their sensitivity was 92.60%, 55.60%, 77.80%, 77.40%, 71.00%, 74.20%, 77.40% and 87.10% respectively. Their specificity was 71.00%, 90.30%, 74.20%, 49.10%, 66.70%, 77.80%, 70.40% and 85.20% respectively. The ■ values were 26.25, 15.00, 23.18, 0.43, 0.18, 0.85, 0.08 and 0.35 respectively. Conclusions The indexes of predicting the need for mechanical ventilation in early stage of AOPP are APACHE Ⅱ, PSS, P (A-a) O2, SBE, AChE, SaO2, PaO2 and PaO2/FiO2, among which PaO2/FiO2 is the most advantageous one.