Background: Massive hemorrhage during craniofacial surgery is common and often results in hypovolemia and hypotension. We conducted this study to assess the effect of the addition of routine central venous pressure (CVP) monitoring on the incidence of intraoperative hypotension and to evaluate the relationship between CVP and hypotension in this population.
Methods: Data from our prospective craniofacial perioperative registry for children 6 to 24 months of age undergoing cranial vault reconstruction with CVP monitoring were compared with data from a historical cohort without CVP monitoring. The incidence and duration of hypotension in the 2 cohorts were compared. In the cohort of subjects with CVP monitoring who experienced hypotension, CVP at the onset of hypotension (T0) was compared with CVP 5 minutes before (T-5) and 5 minutes after (T+5) the onset of hypotension and with the baseline CVP. The amount of time spent at various CVP levels below the baseline, and the associated incidence of hypotension were also determined.
Results: Data from 57 registry subjects were compared with data from 115 historical cohort subjects. The median total duration of hypotension in subjects experiencing hypotension was 278 seconds in the CVP cohort versus 165 seconds in the historical cohort; the median difference was 98 seconds (95% confidence interval [CI], -45 to 345 seconds). The incidence of hypotension was 18% in the CVP cohort versus 21% in the historical cohort; the difference in the incidence of hypotension was -3% (95% CI, -10% to 15%). Analysis using a linear mixed effects model showed a significant decrease in CVP from T-5 to T0 (95% CI, -0.9 to -2.2 mm Hg), a significant increase in CVP from T0 to T+5 (95% CI, 1.0-2.4 mm Hg), no significant difference in CVP between T-5 and T+5 (95% CI, -0.9 to 0.9 mm Hg), and a significant decrease in CVP from baseline to T0 (95% CI, -3.4 to -2.1 mm Hg). CVP at T0 was less than the baseline CVP in 97% of hypotensive episodes. When all cases were examined, CVP was ≥3 mm Hg below the baseline for 16% of the total time studied, with an associated incidence of hypotension of 2%.
Conclusions: The implementation of routine CVP monitoring was not associated with a decreased incidence and likely was not associated with a decreased duration of hypotension in this population experiencing massive hemorrhage. Hypotension was associated with a decrease in CVP, and resolution of hypotension was associated with an increase in CVP to prehypotensive levels. However, significant decreases in CVP below the baseline were common and usually not associated with hypotension. The routine use of CVP monitoring in these children is of questionable utility as a means to decrease the incidence and duration of hypotension.