title: Arterial to end-tidal carbon dioxide difference in neurosurgical patients undergoing craniotomy: a review of practice.
abstract: OBJECTIVE
  To see if PETCO2 reflects PaCO2 with acceptable accuracy.
  
  
  METHODS
  In this audit the.anaesthetic chart of fifty consecutive patients, age 12 years and above undergoing craniotomy for intracranial pathology, were reviewed.
  
  
  RESULTS
  The difference between end tidal carbon dioxide (ETCO2) value corresponding to the time of taking the arterial sample and the PaCO2 was calculated. The mean end tidal CO2 was 29.3 +/- 2.8 and the mean PaCO2 was 32.63 +/- 4.5. The mean difference between the two values was calculated as 4.09 +/- 3.0. The regression coefficient was 0.496, which showed a moderate association. A wide variability was observed in the results.
  
  
  CONCLUSIONS
  Based on our results we recommend that arterial samples should be taken to determine PaCO2 in neurosurgical patients where maintenance of cerebral blood flow is crucial e.g. cerebral aneurysm surgery
authors: Department of Anaesthesia, Aga Khan University, Karachi.
authors: Fauzia Anis
authors: FA
authors: Khan
authors: Mueenullah
authors: M
authors: Khan
authors: Shemila
authors: S
authors: Abbasi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis; D001785:Blood Gas Monitoring, Transcutaneous; D002245:Carbon Dioxide / Q000378:metabolism*; D002560:Cerebrovascular Circulation; D002648:Child; D003399:Craniotomy; D005260:Female; D006801:Humans; D008297:Male; D008485:Medical Audit; D008875:Middle Aged; D009493:Neurosurgery / Q000379:methods*; D010313:Partial Pressure; D010865:Pilot Projects; D013990:Tidal Volume
chemical_list: D002245:Carbon Dioxide