Comparison between respiratory changes in the inferior vena cava diameter and pulse pressure variation to predict fluid responsiveness in postoperative patients.
The objective of our study was to assess the reliability of the distensibility index of the inferior vena cava (dIVC) as a predictor of fluid responsiveness in postoperative, mechanically ventilated patients and compare its accuracy with that of the pulse pressure variation (PPV) measurement.



We included postoperative mechanically ventilated and sedated patients who underwent volume expansion with 500mL of crystalloids over 15minutes. A response to fluid infusion was defined as a 15% increase in the left ventricular outflow tract velocity time integral according to transthoracic echocardiography. The inferior vena cava diameters were recorded by a subcostal view using the M-mode and the PPV by automatic calculation. The receiver operating characteristic (ROC) curves were generated for the baseline dIVC and PPV.



Twenty patients were included. The area under the ROC curve for dIVC was 0.84 (95% confidence interval, 0.63-1.0), and the best cutoff value was 16% (sensitivity, 67%; specificity, 100%). The area under the ROC curve for PPV was 0.92 (95% confidence interval, 0.76-1.0), and the best cutoff was 12.4% (sensitivity, 89%; specificity, 100%). A noninferiority test showed that dIVC cannot replace PPV to predict fluid responsiveness (P=.28).



The individual PPV discriminative properties for predicting fluid responsiveness in postoperative patients seemed superior to those of dIVC.
Departamento de Anestesiologia, Dor e Terapia Intensiva, Universidade Federal de São Paulo, São Paulo, SP 04024-900, Brazil.
Olivia Haun
OH
de Oliveira
Departamento de Anestesiologia, Dor e Terapia Intensiva, Universidade Federal de São Paulo, São Paulo, SP 04024-900, Brazil. Electronic address: flaviogrf@yahoo.com.br.
Flávio Geraldo Rezende de
FG
Freitas
Departamento de Anestesiologia, Dor e Terapia Intensiva, Universidade Federal de São Paulo, São Paulo, SP 04024-900, Brazil.
Renata Teixeira
RT
Ladeira
Departamento de Cardiologia, Universidade Federal de São Paulo, São Paulo, SP 04024-900, Brazil.
Claudio Henrique
CH
Fischer
Departamento de Anestesiologia, Dor e Terapia Intensiva, Universidade Federal de São Paulo, São Paulo, SP 04024-900, Brazil.
Antônio Tonete
AT
Bafi
Departamento de Anestesiologia, Dor e Terapia Intensiva, Universidade Federal de São Paulo, São Paulo, SP 04024-900, Brazil.
Luciano Cesar Pontes
LC
Azevedo
Departamento de Anestesiologia, Dor e Terapia Intensiva, Universidade Federal de São Paulo, São Paulo, SP 04024-900, Brazil.
Flávia Ribeiro
FR
Machado
D001794:Blood Pressure / Q000502:physiology*; D016638:Critical Illness / Q000628:therapy*; D004452:Echocardiography; D005260:Female; D005440:Fluid Therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D011184:Postoperative Period; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013514:Surgical Procedures, Operative; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging / Q000503:physiopathology*
Echocardiography; Fluid therapy; Hemodynamics; Inferior vena cava; Postoperative care