Abstract
BACKGROUND: Estimating left ventricular filling pressures (LVFP) is a crucial component of hemodynamic monitoring in critically ill patients. While non-invasive techniques such as Doppler echocardiography have been validated in non-critical populations, their application in mechanically ventilated patients remains less well-documented. OBJECTIVE: This study aims to evaluate the accuracy of Doppler echocardiography in predicting LVFP, as assessed by pulmonary artery occlusion pressure (PAOP), in mechanically ventilated patients admitted to the intensive care unit (ICU). METHODS: We conducted a systematic review and meta-analysis of peer-reviewed studies focusing on critically ill patients undergoing mechanical ventilation in the ICU (Population-P). The intervention (I) was the assessment of LVFP using transthoracic or transesophageal echocardiography. The comparator (C) was PAOP measurement obtained via a pulmonary artery catheter. The primary outcomes (O) included the accuracy of echocardiographic measurements and their correlation with PAOP. We searched three databases (PubMed/Medline, Scopus, and Embase), screened relevant articles, synthesized the data, assessed study quality using standard tools, and graded the level of evidence with GRADE criteria. A meta-analysis was performed for comparable findings. RESULTS: Of 3596 studies initially identified, 18 prospective studies (n = 696 patients) met the inclusion criteria, with 8 studies (n = 342 patients) included in the meta-analysis. All studies featured small sample sizes (less than 100 patients). Six studies evaluated E/A ratios, and four E/E' ratios. in relation to PAOP. The area under the receiver operating characteristic (AUROC) curve ranged from 0.69 to 0.83 for E/A and from 0.60 to 0.91 for lateral E/E' in predicting PAOP ≥ 18 mmHg. Both E/A and lateral E/E' showed a correlation with PAOP, with pooled correlation coefficients of 0.48 (95% confidence intervals [CI]: 0.48-0.58) and 0.72 (95% CI: 0.52-0.92), respectively. Study quality ranged from low to high and heterogeneity was high the overall level of evidence was deemed very low. CONCLUSIONS: Doppler echocardiography shows potential for assessing LVFP in critically ill patients on mechanical ventilation. However, limitations such as small sample sizes and study heterogeneity, including the use of different PAOP cut-off values to define elevated LVFP, highlight the need for further research to strengthen its role in this setting.