ABSTRACT
OBJECTIVES: Cardiac output (CO) measurements in the ICU are usually based on invasive techniques, which are technically complex and associated with clinical complications. This study aimed to compare CO measurements obtained from a noninvasive photoplethysmography-based device to a pulse contour cardiac output device in ICU patients. DESIGN: Observational, prospective, comparative clinical trial. SETTING: Single-center general ICU. PATIENTS: Patients admitted to the general ICU monitored using a pulse contour cardiac output device as per the decision of the attending physician. INTERVENTIONS: Parallel monitoring of CO using a photoplethysmography-based chest patch device and pulse contour cardiac output while the medical team was blinded to the values obtained by the noninvasive device. MEASUREMENTS AND MAIN RESULTS: Seven patients (69 measurements) were included in the final analysis. Mean CO were 7.3 ± 2.0 L/m and 7.0 ± 1.5 L/m for thermodilution and photoplethysmography, respectively. Bland-Altman showed that the photoplethysmography has a bias of 0.3 L/m with -1.6 and 2.2 L/m 95% limit of agreement (LOA) and a bias of 2.4% with 95% LOA between -25.7% and 30.5% when calculating the percentage of difference from thermodilution. The values obtained by thermodilution and photoplethysmography were highly correlated (r = 0.906). CONCLUSIONS: The tested chest patch device offers a high accuracy for CO compared to data obtained by the pulse contour cardiac output and the thermodilution method in ICU patients. Such devices could offer advanced monitoring capabilities in a variety of clinical settings, without the complications of invasive devices.
ABSTRACT
AIMS: Heart failure with preserved ejection fraction can lead to pulmonary hypertension. The aim of the present study was to evaluate the role of exercise during right heart catheterization in the unmasking of diastolic dysfunction. METHODS AND RESULTS: Between 2004 and 2012, 200 symptomatic patients with exertional dyspnoea, preserved left ventricular systolic function and suspected pulmonary hypertension, underwent right heart catheterization. Included in the study were 63 patients with resting pulmonary arterial wedge pressure (PAWP) ≤15 mmHg. Patients were divided to three tertiles based on their peak exercise PAWP. Mean age was 60 ± 20 years and 29% were males. Mean pulmonary arterial pressure was 31 ± 14 mmHg at rest and 42 ± 18 mmHg upon exercise. Mean change in PAWP between rest and exercise was 0.0 ± 4.3, 4.6 ± 2.4, and 16.6 ± 7.1 mmHg in the lower, middle, and upper tertiles, respectively (P < 0.001). Higher exercise PAWP tertiles were associated with reduced pulmonary vascular resistance (8.3 ± 6.7, 2.9 ± 2.7, and 5.8 ± 4.6 Woods units, respectively; P = 0.004). A multivariate linear regression model demonstrated that each 5 kg/m(2) increase in body mass index was associated with 2.5 ± 1.0 mmHg increase in exercise PAWP (P = 0.017). A multivariate binary logistic model showed that subjects with borderline PAWP at rest (12-15 mmHg) were 4.5 times more likely to be in the upper tertile of exercise PAWP (P = 0.011). CONCLUSIONS: In symptomatic patients with pulmonary hypertension, preserved left ventricular ejection fraction and PAWP ≤15 mmHg, exercise during right heart catheterization may unmask diastolic dysfunction. This is especially true for obese patients and patients with borderline resting PAWP.
