الفهرس 
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Abstract
Organophosphorous compounds (OPC), the most worldwide used insecticides, may cause serious poisoning either accidentally or by deliberate ingestion. There are no rules for regulations governing the purchase of these products, and they are therefore readily available ”over the counter.
With the development of emergency medicine, a need arose for evaluation scales that would provide rapid triage and objective status assessment .There is growing interest in intensive care medicine in scoring systems for measuring the severity of illness and predicting outcome in critically ill patients.
Subjective evaluations of clinical status by individual clinicians may differ in terminology, and even in measurement of the severity of illness. Hence, various descriptive and prognostic evaluation scales (scoring systems) have been developed during the past three decades. Objective evaluation of clinical status would facilitate comparison of methods, staff, clinical centers and studies.
This study was carried out to evaluate the value of the Simplified Acute Physiology Score II (SAPS II) and the Acute Physiology and Chronic Health Evaluation IV (APACHE IV) in the prediction of outcome in patients with acute organophosphate poisoning (OPP) requiring admission to the ICU of Poison Control Center (PCC) of Ain Shams University Hospital.
This study is a prospective analytic study that was conducted between January 1st, 2009 and December 31st, 2009 on all patients with acute organophosphate compounds (OPC) poisoning admitted to the Intensive Care Unit (ICU) of Poison Control Center (PCC) of Ain Shams University Hospital. Their number is 90 patients.
All data was being collected concurrently for consecutive ICU admissions. In each patient, sociodemographic data, poisoning data, investigational parameters, treatment data and calculation of APACHE IV and SAPS II score were collected.
Concerning the age of the patient it was found that the ages of the patients ranged from 16 to 55 years and the mean age was (31.48 + 9.90) years.
Regarding the gender of the patients, it was found that 40 patients (44.4 %) are males out of them 37(41.1%) survived and 3 (3.3%) non survived and 50 patients (55.6%) are females out of them 41(45.6%) survived and 9 (10%) non survived with a male to female ratio 1:1.2.
Concerning the residence of the patients, it was found that the majority of patients are from urban areas 56 patients (62.2%) out of them 45(50%) patients survived and 11 (12.2%) didn’t survive and 34 patients (37.8%) are from rural areas; 33(36.7%) patients from them survived and only one (1.1%) didn’t survive.
Regarding the occupation of the patients, it was found that Acute organophosphate intoxication occurred more frequently in unemployed 25 (27.8 %) followed by housewives 21 (23.3%), manual workers 14 (15.6%), civil employer 11 (12.2%), farmers 11 (12.2%), and the least incidence was among students 8 (8.9%).
Concerning the types of OPC used in poisoning, it was found that in most of patients, 57 (63.4%), the type of OPC used could not be identified and all of them are survived, while malathion poisoning was in 30 patients (33.3%) and 12 (13.3) % out of them are non survived and only three patients (3.3%) were known to be poisoned by dimethoate and all of them survived.
Regarding the mode of poisoning, it was found that the majority of patients 79 (87.7%) are intoxicated due to suicidal attempt, out of them 12 (13.3%) patients are non survived, five patients (5.6 %) are intoxicated accidentally and all of them survived, five patients (5.6 %) are due to occupational exposure and all of them are survived and only one patient (1.1%) claimed to be homicidal who survived also.
Regarding the route of poisoning of OPC , it is found that the route of poisoning was mainly by ingestion in 83 patients (92.2%) out of which 12 ( 13,3%) patients didn’t survive, while dermal exposure route occurred in 4 patients (4.5 %) and only three patients (3.3%) inhaled the OPC ,all of them survived.
Regarding the relationship between actual survival and predicted mortality by APACHE IV score according to its best cut-off point, it is found that from 19(21.1%) patients were predicted to die by the score; only 11(12.2%) patients who actually died, and from 71(78.9%) predicted to live, there are 70(77.8%) who actually survived and only 1(1.1%) who actually died.
Regarding the relationship between actual survival and predicted mortality by SAPS II score according to its best cut-off point, it is found that from 21(23.3%) patients were predicted to die by the score only 9 (10%) patients who actually died, and from 69(76.7%) were predicted to live, there are 66(73.3%) who actually survived and only 3(3.3%) who actually died.
Regarding the relationship between predicted mortality by APACHE IV score and predicted mortality by SAPS II score according to their best cut-off point, it is found that from 21(23.3 %) predicted to die by SAPS II score only 17(18.9%) patients who was predicted to die by APACHE IV score, and from 69 (76.7%) predicted to live by SAPS II score, there are 67 (74.4%) who was predicted to live by APACHE IV score.
Regarding the relationship between actual survival and predicted mortality by APACHE IV score & SAPS II score according to their best cut-off point, it is found that from 19( 21%) patients were predicted to die by APACHE IV score only 9( 10%) patients who was predicted to die by SAPS II score and actually 11( 12%) patients who died, and from 71( 78.9%) patients were predicted to live by APACHE IV score, there are 69( 76.7%) who was predicted to live by SAPS II score and actually 78 (86.7%) patients who live.
Concerning the Receiver Operating Characteristic (ROC) curves for APACHE IV, which is used for the estimation of the discriminative power of the model by the area under the ROC curve. The value of the area was 0.921 (standard error 0.0549) for APACHE IV. The area for APACHE IV is excellent. The best cut-off point is (89) with sensitivity (93.59) and specificity (91.67).
Concerning the Receiver Operating Characteristic (ROC) curves for SAPS II, which is used for the estimation of the discriminative power of the model by the area under the ROC curve. The value of the area was 0.807 (standard error 0.0787) for SAPS II. The area for SAPS II is very good. The best cut-off point is (44) with sensitivity (85.90) and specificity (75.00).
Regarding the comparison between the ROC curves of the two models ”APACHE IV and SAPS II” which were plotted to estimate the discriminative power of the models by the area under the ROC curve. The values were (0.921) (standard error 0.0549) for APACHE IV and (0.807) (standard error 0.0787) for SAPS II. The area for SAPS II, although very good but it is less than the area for APACHE IV by (0.114).
The cut-off values, sensitivities, specificities of scoring systems and the area under the ROC curve, it is found that APACHE IV score of (89) or higher was predictive of mortality, with (93.59%) sensitivity and (91.67%) specificity (P< 0.001). SAPS II score of (44) or higher was predictive of mortality, with (85.90%) sensitivity and (75%) specificity (P< 0.001). The area under the curve for APACHE IV is larger than SAPS II.
Concerning the actual, predicted and standardized mortality ratio of the two scores, it was found that the actual mortality in OPP was (13.3 %) (12/90). Predicted mortality rates were (21.1%) and (23.3 %) for APACHE IV and SAPS II, respectively. SMR and 95% CI for APACHE IV was 0.63 (0.53-0.71) and for SAPS II 0.57 (0.46 - 0.66).
Regarding the general characteristics of survivors and non survivors, it was found that all patients in both groups received atropine and obidoxime, but non survivors needed more atropine and obidoxime than survivors. The use of mechanical ventilation was also higher in non survivors. Despite GCS system which shows no significant difference between two groups, the mean scores of APACHE IV and SAPS II were higher in non survivors (99.083) with CI, (91.637 - 106.530) than survivors (77.526) with CI, (75.399 - 79.653).
The APACHE IV and SAPS II scores are shown to discriminate best between survivors and non survivors.