The Effect of Common Interventions in the Intensive Care Unit on Right Ventricular Function After Cardiac Surgery-An Intervention Study.

OBJECTIVE: Critical care therapy after cardiac surgery includes interventions to aid pulmonary and cardiac function. The aim of this study was to investigate the effect of such interventions on right ventricular function (RVF). DESIGN: This was a prospective intervention study. SETTING: This study was conducted at a single tertiary university hospital. PARTICIPANTS: Thirty elective coronary artery bypass graft (CABG) patients were studied in the intensive care unit (ICU) following CABG surgery. INTERVENTIONS: The following interventions were investigated: Trendelenburg position; positive end-expiratory pressure (PEEP) 0, 5, and 10 cmH2O; increased oxygen fraction; and AAI, DDD, and VVI pacing. MEASUREMENTS AND MAIN RESULTS: Transesophageal echocardiography and a pulmonary artery catheter were used to assess hemodynamics and RVF. Transesophageal echocardiography measures included right ventricular (RV) fractional area change, RV ejection fraction, RV stroke volume (SV), and RV global longitudinal strain (RV-GLS). Trendelenburg increased global echocardiographic measures of RVF as well as cardiac output (CO) 0.44 L/min (95% CI: 0.21-0.67). Increasing PEEP from 0 to 10 reduced SV and consequently CO by 0.41 L/min. Pulmonary vascular resistance was not changed by increasing PEEP. AAI or DDD pacing (15 beats above baseline) increased CO 0.35 L/min (95% CI 0.07-0.63). In contrast VVI pacing decreased CO by 24% (1.2 L/min [95% CI 0.9-1.6]). Applying 100% O2 did not affect hemodynamics, but RV-GLS was improved -4.4% (95% CI: -6.9 to -1.9). CONCLUSION: In patients with normal RVF undergoing CABG, several routine interventions in the ICU affect RVF, in particular PEEP and VVI pacing, which induces clinically important reductions in stroke volume.

Severe loss of right ventricular longitudinal contraction occurs after cardiopulmonary bypass in patients with preserved right ventricular output.

Assessment of right ventricular (RV) function is crucial since RV failure with a reduced cardiac output (CO) is associated with compromised outcome in cardiac surgery. Echocardiographic evaluation of RV function is commonly used, but a reduction in tricuspid annular plane systolic excursion (TAPSE) and tricuspid annulus tissue Doppler imaging (S') have been observed independently of clinical signs of RV failure. This has led to uncertainty of these variables' validity in cardiac surgery. To describe transesophageal echocardiographic (TEE) measures of RV function during coronary artery bypass graft surgery with detailed haemodynamic assessment using pulmonary artery catheter (PAC) measurements to describe "natural" changes in the absence of RV failure. We prospectively studied 30 patients with concomitant PAC and TEE measurements at four time-points, namely after: anaesthesia induction, sternotomy, cardiopulmonary bypass (CPB) and upon arrival in the intensive care unit. TAPSE and S' were significantly reduced by 43% (p < 0.0001) and 22% (p = 0.006), respectively after CPB without any change in stroke volume (SV). RV ejection fraction (RVEF), RV fractional area change (RVFAC) and global longitudinal strain (RV-GLS) remained unchanged. SV measured with 3D echocardiography correlated with PAC measured SV (r = 0.66[95% CI 0.50; 0.78], p < 0.0001), but 3D showed a minor, but statistically significant underestimation of SV (8.5 ml (95% CI 2.7 ml; 14 ml, p = 0.004). TAPSE and S' were both reduced after CPB despite maintained CO. RVFAC, RVEF and RV-GLS remained stable, however, these measures were unable to detect minor changes in SV. 3D-echocardiographyshowed a strong correlation with SV measured by thermodilution, but with a consistent underestimation of approximately 10%.

Domain-specific cognitive dysfunction after cardiac surgery. A secondary analysis of a randomized trial.

BACKGROUND: Brain injury and cognitive dysfunction are serious complications after cardiac surgery. In the perfusion pressure cerebral infarcts (PPCI) trial, we allocated cardiac surgery patients to a mean arterial pressure of either 70-80 mm Hg (high-target) or 40-50 mm Hg (low-target) during cardiopulmonary bypass. In this secondary analysis, we aimed to assess potential differences in domain-specific patterns of cognitive deterioration between allocation groups and to investigate any associations of postoperative cognitive dysfunction (POCD) with diffusion-weighted magnetic resonance imaging (DWI)-detected brain lesions. METHODS: Of the 197 patients randomized in the PPCI trial, 89 in the low-target group and 80 in the high-target group had complete DWI datasets, and 92 and 80 patients had complete data for an evaluation of cognitive function at discharge respectively. Cognitive function was assessed prior to surgery, at discharge and at 3 months. DWI was obtained at baseline and on postoperative days 3 to 6. RESULTS: We found no statistically significant differences between the two groups when comparing the proportion of patients with a domain-specific deterioration over the pre-defined critical level in seven individual test variables at discharge. Significant deterioration was most common in tests thought to assess cognitive flexibility and interference susceptibility and least common in the memory test. POCD at discharge was more frequent in patients with DWI-positive brain lesions (OR adjusted for age and group allocation: 2.24 [95% CI 1.48-3.00], P = 0.036). CONCLUSIONS: Domain-specific patterns of POCD were comparable between groups. A significant association was seen between DWI-positive brain lesions and POCD.