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[Noninvasive preoperative estimation of pulmonary vascular resistance of the patients waiting for two staged Fontan procedure].

OBJECTIVE
Noninvasive method for estimating the pulmonary vascular resistance (PVR) was used in patients waiting for two staged Fontan procedure to observe the relationship between estimated PVR and surgical results.


METHODS
Thirty-three candidate patients for two staged Fontan procedures were randomly selected for this trial. Preoperative hemoglobin (HGB), hematocrit (HCT) and pulse oxygen saturation (SpO2) were measured. Estimated PVRs were then calculated by the regression equations. The cases were divided into three groups of low risk group with PVR less than 2.4 wood, high risk group with PVR between 2.4 to 3.2 wood, and extremely high risk group with PVR more than 3.2 wood. The incidences of postoperative low cardiac output and multi-organ failure were compared. Simultaneously, the cases without or with postoperative severe low cardiac output and multi-organ failure after operation were divided into two groups. The preoperative HGB, HCT and estimated PVR among the groups were analyzed.


RESULTS
The rates of postoperative severe low cardiac output and multi-organ failure were 10.0%, 32.4% and 63.6% for the patients of low, high and extremely high risk groups respectively. The difference was significant (P < 0.01). The preoperative HGB, HCT, SpO2 and PVR were all significantly different between the patients without or with postoperative severe low cardiac output and multi-organ failure. The PVR (HGB) were (2.53 +/- 0.56) wood and (3.24 +/- 0.58) wood respectively. The PVR (HCT) were (2.59 +/- 0.58) wood and (3.21 +/- 0.79) wood respectively. The PVR (SpO2) were (2.22 +/- 0.55) wood and (2.93 +/- 0.58) wood, respectively. The differences were all significant (t = 3.25, 2.52 and 3.33 respectively, P < 0.01 or 0.05).


CONCLUSIONS
Preoperative estimated PVRs calculated by HGB, HCT and SpO2 were comparable with the postoperative results. Thus, the invasive preoperative estimation of pulmonary vascular resistance could be a method in estimating the surgical indication and predicting the surgical result for two stage Fontan procedure.