Delta down compared with delta pulse pressure as an indicator of volaemia during intracranial surgery.
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.
Deflandre
E
E
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
Bonhomme
V
V
Hans
P
P
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