title: Delta down compared with delta pulse pressure as an indicator of volaemia during intracranial surgery.
abstract: BACKGROUND
  Delta pulse pressure (DPP) and delta down (DD) are indicators of volaemia. The threshold value of DPP for discriminating between responders and non-responders to fluid loading (FL) is 13%. This study aimed at comparing DD with DPP during intracranial surgery.
  
  
  METHODS
  Twenty-six adult patients undergoing scheduled intracranial surgery under general anaesthesia were enrolled. DD and DPP were simultaneously measured every 10 min. A DPP>13% on two consecutive occasions prompted a 250 ml FL. Pairs of data were analysed using regression analysis, receiver operating characteristics (ROC) curve, and prediction probability (Pk).
  
  
  RESULTS
  We found a significant correlation between DD and DPP (R2=0.5431, P<0.001). ROC curve analysis revealed an excellent accuracy of DD in predicting a DPP value higher or lower than 13% (area under the curve: 0.967, se: 0.013). The DD threshold associated with the best sensitivity (0.90) and specificity (0.99) was 5 mm Hg. The Pk of DD to predict a DPP value higher or lower than 13% was 0.97 (se: 0.01). A total of 41 FL performed in 19 patients resulted in a decrease of DD and DPP below 5 mm Hg and 13%, respectively, in all but one occasion.
  
  
  CONCLUSIONS
  DD is as efficient as DPP to assess hypovolaemia and predict responsiveness to FL in patients undergoing intracranial surgery. A 5 mm Hg DD value can be considered as a valuable threshold for initiating FL. These results support its use during intracranial surgery.
authors: University Department of Anaesthesia and Intensive Care Medicine, CHR de la Citadelle, Bd du 12eme de Ligne, 1, 4000 Liege, Belgium. eric.deflandre@gmail.com
authors: E
authors: E
authors: Deflandre
authors: V
authors: V
authors: Bonhomme
authors: P
authors: P
authors: Hans
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000768:Anesthesia, General / Q000379:methods; D001794:Blood Pressure; D001795:Blood Pressure Determination / Q000379:methods; D003399:Craniotomy; D004812:Epidemiologic Methods; D005260:Female; D005440:Fluid Therapy / Q000379:methods*; D006801:Humans; D020896:Hypovolemia / Q000175:diagnosis* / Q000628:therapy; D007430:Intraoperative Care / Q000379:methods; D007431:Intraoperative Complications / Q000175:diagnosis* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D011673:Pulsatile Flow; D012121:Respiration, Artificial