Milo Engoren

Role of hemodilutional anemia and transfusion during cardiopulmonary bypass in renal injury after coronary revascularization: Implications on operative outcome*

Objective:Acute renal injury and failure (ARF) after cardiopulmonary bypass (CPB) has been linked to low on-pump hematocrit (hematocrit). We aimed to 1) elucidate if and how this relation is modulated by the duration of CPB (TCPB) and on-pump packed red blood cell transfusions and 2) to quantify the impact of post-CPB renal injury on operational outcome and resource utilization. Design:Retrospective review. Setting:A Northwest Ohio community hospital. Patients:Adult coronary artery bypass surgery patients with CPB but no preoperative renal failure. Interventions:None. Measurements and Main Results:We quantified post-CPB renal injury via 1) the peak postoperative change in serum creatinine (Cr) level relative to pre-CPB values (%&Dgr;Cr) and 2) ARF, defined as the coincidence of post-CPB Cr ≥2.1 mg/dL and >2 times pre-CPB Cr. The separate effects of lowest hematocrit, intraoperative packed RBC transfusions, and TCPB on %&Dgr;Cr and ARF were derived via multivariate regression, overlapping quintile subgroup analyses, and propensity matching. Lowest hematocrit (22.0% ± 4.6% sd), TCPB (94 ± 35 mins), and pre-CPB Cr (1.01 ± 0.23 mg/dL) varied widely. %&Dgr;Cr varied substantially (24 ± 57%), and ARF was documented in 89 patients (5.1%). Both %&Dgr;Cr (p < .001) and ARF (p < .001) exhibited sigmoidal dose-dependent associations to lowest hematocrit that were 1) modulated by TCPB such that the renal injury was exacerbated as TCPB increased, 2) worse in patients with relatively elevated pre-CPB Cr (≥1.2 mg/dL), and 3) worse with intraoperative packed red blood cell transfusions (n = 385; 21.9%), in comparison with patients at similar lowest hematocrit. Operative mortality (p < .01) and hospital stays (p < .001) were increased systematically and significantly as a function of increased post-CPB renal injury. Conclusions:CPB hemodilution to hematocrit <24% is associated with a systematically increased likelihood of renal injury (including ARF) and consequently worse operative outcomes. This effect is exacerbated when CPB is prolonged with intraoperative packed red blood cell transfusions and in patients with borderline renal function. Our data add to the concerns regarding the safety of currently accepted CPB practice guidelines.

Determinants of prolonged mechanical ventilation after coronary artery bypass grafting

BACKGROUND Early extubation of cardiac surgical patients enhances ambulation, improves cardiopulmonary function, and can lead to savings in health care costs. METHODS We retrospectively examined the role of 48 variables in determining the period of ventilatory support in 507 patients having coronary artery bypass grafting. RESULTS Fifteen (< 3%) of 507 patients required ventilatory support in excess of 24 hours. Among the remaining patients, extubation was achieved early (< or = 8 hours) (mean time, 5.65 +/- 1.31 hours) in 53% and late (> 8 hours) (mean time, 13.7 +/- 3.4 hours) in 47%. Logistic and linear multivariate regression analyses implicated increased age, New York Heart Association functional class IV, intraoperative fluid retention, postoperative intraaortic balloon pump requirement, and bank blood transfusions as predictors of late extubation. Also, the linear regression linked lower body weight and number of anastomoses (or grafts) to increased mechanical ventilatory support. CONCLUSIONS Analysis of the fluid balance and cardiopulmonary bypass data suggests that earlier extubation may be achieved by actively reducing fluid retention (eg, by hemoconcentration) and time on bypass (eg, normothermia). Finally, intensive care unit stay and postoperative length of stay were significantly lower in the early versus late extubation groups without an increase in pulmonary complications.

Approximate entropy of respiratory rate and tidal volume during weaning from mechanical ventilation.

OBJECTIVE To determine the effects of respiratory failure on respiratory rate pattern and tidal volume pattern. DESIGN Prospective, clinical study. SETTING Cardiovascular intensive care unit. PATIENTS Ten patients within 12 hrs of cardiac surgery, and 21 patients who required prolonged (>7 days) mechanical ventilation. INTERVENTIONS Patients were placed on spontaneous ventilation for weaning trials. MEASUREMENTS AND MAIN RESULTS During spontaneous ventilation, each breaths instantaneous respiratory rate and tidal volume were recorded for later analysis. Approximate entropy (ApEn) was calculated for respiratory rate and tidal volume series of the terminal 1000 breaths on each spontaneous ventilation trial in series of 100, 300, and 1000 breaths. Ten patients (controls) were studied and extubated within 12 hrs of cardiac surgery. The other 21 patients were studied during attempts to wean them from mechanical ventilation. These patients passed (Group V-Pass) 59 and failed (Group V-Fail) 14 weaning trials. Mean tidal volume did not vary between groups, but respiratory rate increased progressively from the control group to Group V-Pass to Group V-Fail (p < .017). Conversely, approximate entropy of respiratory rate (ApEn-RR) did not vary among the three groups at any time series length, but approximate entropy of tidal volume (ApEn-VT) increased from the control group to Group V-P (p< .017) to Group V-F (p< .017) at all time series lengths. ApEn-VT was very specific but only moderately sensitive at identifying respiratory failure. CONCLUSION Respiratory failure causes tidal volume patterns to become increasingly irregular, but increasing respiratory rate has no effect on respiratory rate pattern.

A comparison of fentanyl, sufentanil, and remifentanil for fast-track cardiac anesthesia

Cardiac surgery is estimated to cost

Long-term survival and health status after prolonged mechanical ventilation after cardiac surgery.

27 billion annually in the United States. In an attempt to decrease the costs of cardiac surgery, fast-track programs have become popular. The purpose of this study was to compare the effects of three different opioid techniques for cardiac surgery on postoperative pain, time to extubation, time to intensive care unit discharge, time to hospital discharge, and cost. Ninety adult patients undergoing cardiac surgery were randomized to a fentanyl-based, sufentanil-based, or remifentanil-based anesthetic. Postoperative pain was measured at 30 min after extubation and at 6:30 am on the first postoperative day. Pain scores at both times were similar in all three groups (P > 0.05). Median ventilator times of 167, 285, and 234 min (P > 0.05), intensive care unit stays of 18.8, 19.8, and 21.5 h (P > 0.05), and hospital stays of 5, 5, and 5 days (P > 0.05) for the Fentanyl, Sufentanil, and Remifentanil groups did not differ. Three patients needed to be tracheally reintubated: two in the Sufentanil group and one in the Fentanyl group. Median anesthetic costs were largest in the Remifentanil group (

The effect of erythrocyte blood transfusions on survival after surgery for hip fracture.

140.54 [

Preoperative and intraoperative predictors of postoperative acute respiratory distress syndrome in a general surgical population.

113.54–

The effect of prompt physician visits on intensive care unit mortality and cost

179.29]) and smallest in the Fentanyl group (

The Effect on Long-Term Survival of Erythrocyte Transfusion Given for Cardiac Valve Operations

43.33 [

Regional versus general anesthesia in surgical patients with chronic obstructive pulmonary disease: does avoiding general anesthesia reduce the risk of postoperative complications?

39.36–