Background:Monitoring of cardiac output (CO) is important for promising safe approach to goal-directed hemodynamic therapy for delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH), but is often precluded by the invasiveness and complexity of ongoing monitoring modalities. We examined the clinical utility of less-invasive management using an uncalibrated arterial pressure waveform-derived cardiac output (APCO) monitor with refined algorithm (Third-generation FloTrac/Vigileo, Edwards, Irvine, CA, USA) during hyperdynamic therapy for post-SAH DCI, compared with transpulmonary thermodilution (PiCCO, Pulsion, Munich, Germany) as a reference technique.Methods:Forty-five patients who underwent surgical clipping within 24 h of SAH onset and subsequently developed clinical deterioration attributable to DCI were investigated. Validation of the APCO-derived cardiac index (CI) during dobutamine-induced hyperdynamic therapy was compared with a reference CI analyzed by transpulmonary thermodilution in 20 patients. In a subsequent trial of 48 cases, the overall clinical results from patients managed with each device were compared.Results:The APCO underestimated CI with an overall bias ± SD of 0.33 ± 0.26 L/min/m2 compared with transpulmonary thermodilution, resulting in an error of 14.9%. The trends of CI for both techniques at each dobutamine dose were similar (r2= 0.77; P < 0.0001). No statistically significant differences were observed between the device groups for frequencies of neurological improvement, cerebral infarction, cardiopulmonary complications, or functional outcomes at 3 months.Conclusions:These data suggest that the refined APCO tends to underestimate CI compared with reference transpulmonary thermodilution during hyperdynamic therapy with dobutamine for reversing DCI, but may be acceptable in this select category of patients to obtain comparable clinical results.