title: Clinical profile and outcome of patients hospitalized with dimethyl and diethyl organophosphate poisoning.
abstract: The two major classes of organophosphate compounds, dimethyl and diethyl organophosphates, have different toxicokinetic properties. This study evaluated the clinical profile and outcomes in patients admitted with poisoning with these two classes of organophosphates.
  
  
  METHODS
  This retrospective study spanned 6 years (2002-2007). Patients were treated with atropine and supportive care including ventilation, as required, and followed up until death or hospital discharge. Oximes were not administered. Of the 422 charts retrieved, 396 fulfilled inclusion criteria. Data on the clinical profile, ventilation, length of hospital stay, incidence of intermediate syndrome and mortality were extracted.
  
  
  RESULTS
  The mean (± standard deviation) age was 31.4 ± 12.7 years with a male preponderance (2.6:1). The median (interquartile range (IQR)) admission pseudocholinesterase level of 317 (222-635) U/L indicated significant inhibition of cholinesterase activity. The median lag-time to presentation to our hospital was 5 (IQR 3-8.5) hours. Oximes were administered at a primary center in 33 patients (8.3%). Dimethyl organophosphate was ingested by 141 patients, diethyl organophosphate by 108, S-alkyl organophosphate by 2, and an un-identified organophosphate by 145 patients. Ventilation was required in 260 patients (65.7%); the median duration of ventilation being 7.5 (IQR 3-12) days. Overall mortality was 13.1%. There was a significant difference between dimethyl and diethyl organophosphate compounds in ventilatory requirement (76% vs. 56%, adjusted odds ratio (OR) 2.37, 95% CI 1.01-5.57, p=0.047), duration of ventilation (11 (4-15) vs. 5 (2-9) days, adjusted OR 1.12, 95%CI 1.04-1.21, p=0.002) and incidence of intermediate syndrome (72/125 (58%) vs. 24/92 (26%), adjusted OR 2.84, 95%CI 1.38-5.86, p=0.004). Mortality was similar in the two groups (20/141 (14%) vs. 7/108 (6%), dimethyl vs. diethyl organophosphate, adjusted OR 1.29, 95%CI 0.43-3.94, p=0.65).
  
  
  CONCLUSIONS
  Patients admitted with dimethyl organophosphate poisoning have a worse outcome compared with diethyl organophosphate poisoning for clinically relevant patient outcomes.
authors.affiliation: Medical Intensive Care Unit, Christian Medical College and Hospital, Vellore, India. peterjohnvictor@yahoo.com.au
authors.forename: John Victor
authors.initials: JV
authors.lastname: Peter
authors.forename: Jayakumar
authors.initials: J
authors.lastname: Jerobin
authors.forename: Anupama
authors.initials: A
authors.lastname: Nair
authors.forename: Anjana
authors.initials: A
authors.lastname: Bennett
authors.forename: Prasanna
authors.initials: P
authors.lastname: Samuel
authors.forename: Anugrah
authors.initials: A
authors.lastname: Chrispal
authors.forename: Ooriapadickal Cherian
authors.initials: OC
authors.lastname: Abraham
authors.forename: Kuruvilla Prasad
authors.initials: KP
authors.lastname: Mathews
authors.forename: Jude Joseph
authors.initials: JJ
authors.lastname: Fleming
authors.forename: Anna
authors.initials: A
authors.lastname: Oommen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001285:Atropine / Q000627:therapeutic use; D005260:Female; D017052:Hospital Mortality; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D062025:Organophosphate Poisoning; D012121:Respiration, Artificial; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D001285:Atropine