Reduction of Intra-abdominal Hypertension Is Associated with Increase of Cardiac Output in Critically Ill Patients Undergoing Mechanical Ventilation

Objective: To demonstrate the relationship between intra-abdominal hypertension (IAH) and cardiac output (CO) in mechanically ventilated (MV), critically ill patients.

Material and methods: This was a single-center, prospective study performed between January and April 2016, on 30 mechanically ventilated patients (mean age 67.3 ± 11.9 years), admitted in the Intensive Care Unit (ICU) of the Emergency County Hospital of Tîrgu Mureș, Romania, who underwent measurements of intra-abdominal pressure (IAP). Patients were divided into two groups: group 1 – IAP <12 mmHg (n = 21) and group 2 – IAP >12 mmHg (n = 9). In 23 patients who survived at least 3 days post inclusion, the variation of CO and IAP between baseline and day 3 was calculated, in order to assess the variation of IAP in relation to the hemodynamic status.

Results: IAP was 8.52 ± 1.59 mmHg in group 1 and 19.88 ± 8.05 mmHg in group 2 (p <0.0001). CO was significantly higher in group 1 than in the group with IAH: 6.96 ± 2.07 mmHg (95% CI 6.01–7.9) vs. 4.57 ± 1.23 mmHg (95% CI 3.62–5.52) (p = 0.003). Linear regression demonstrated an inverse correlation between CO and IAP (r = 0.48, p = 0.007). Serial measurements of CO and IAP proved that whenever accomplished, the decrease of IAP was associated with a significant increase in CO (p = 0.02).

Conclusions: CO is significantly correlated with IAP in mechanically ventilated patients, and IAH reduction is associated with increase of CO in these critically ill cases.