Accuracy of Vigileo/Flotrac monitoring system in morbidly obese patients.
OBJECTIVE
Our goal was to assess the accuracy of measuring cardiac output (CO) by the FloTrac/Vigileo (CO(V)) device in comparison with thermodilution technique through pulmonary artery catheterization (PAC(TD)) in morbidly obese patients.


METHODS
Cardiac output in 8 morbidly obese patients was assessed twice at upright and lying position breathing ambient air. At least 4 consecutive CO measurements with 10 mL of ice-cold saline injections were performed each time. Simultaneous CO measurements were recorded with both single-bolus thermodilution and CO(V).


RESULTS
One hundred thirty-two CO data pairs were collected. The overall mean single-bolus thermodilution 6.2 ± 1.1 L/min was lower than the overall mean CO(V) 7.8 ± 1.6 L/min (P < .001). Lin concordance coefficient indicated that overall agreement between PAC(TD) and CO(V) was poor, 0.29. Lin concordance coefficient in sitting position was 0.29, 95% confidence interval (0.17-0.40) and in lying position was 0.30, 95% confidence interval (0.15-0.44). The Bland-Altman plot analysis showed systematically higher values from CO(V) in comparison with PAC(TD). These differences increased in presence of high CO measurements. In 3 of 8 patients, the percentage error was lower than 20%, whereas in the other 5, it was higher than 20%. Of these 5, in 2 cases, the percentage error was greater than 50%.


CONCLUSIONS
Data obtained using CO(V) vs PAC(TD) measurements showed poor correlation. The results were not interchangeable.
Anesthesiology Department, Hospital Clinic of Barcelona, Barcelona, Spain. Electronic address: ana.tejedor@hotmail.com.
Ana
A
Tejedor
Anesthesiology Department, Hospital Clinic of Barcelona, Barcelona, Spain. Electronic address: erivas@clinic.ub.es.
Eva
E
Rivas
Biostatistics and Data Management Core Facility, IDIBAPS, Hospital Clinic of Barcelona, Barcelona, Spain; Biostatistics Unit, Faculty of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain. Electronic address: Jose.Rios@uab.cat.
Jose
J
Ríos
Pneumology Deparment, Hospital Clinic of Barcelona, Barcelona, Spain. Electronic address: earismen@clinic.ub.es.
Ebymar
E
Arismendi
Anesthesiology Department, Hospital Clinic of Barcelona, Barcelona, Spain. Electronic address: gmartin@clinic.ub.es.
Graciela
G
Martinez-Palli
Gastrointestinal Department, Hospital Clinic of Barcelona, Barcelona, Spain. Electronic address: sdelgado@clinic.ub.es.
Salvadora
S
Delgado
Anesthesiology Department, Hospital Clinic of Barcelona, Barcelona, Spain. Electronic address: jbalust@clinic.ub.es.
Jaume
J
Balust
D050110:Bariatric Surgery; D002302:Cardiac Output; D002407:Catheterization, Swan-Ganz / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D008991:Monitoring, Physiologic / Q000295:instrumentation; D009767:Obesity, Morbid / Q000503:physiopathology*; D056888:Patient Positioning / Q000379:methods; D011187:Posture / Q000502:physiology; D013815:Thermodilution / Q000379:methods*
Cardiac output; Obese patient; Pulmonary artery catheter; Vigileo/FloTrac