Utility of cerebral oxymetry for assessing cerebral arteriolar carbon dioxide reactivity during cardiopulmonary bypass.

BACKGROUND: Our study evaluated changes in cerebral arterial oxygen saturation (rSO2) during cardiopulmonary bypass (CPB) that were caused by changes in arterial carbon dioxide tension (PaCO2). METHODS: A group of 126 patients undergoing routine, elective, first-time coronary artery bypass graft surgery (CABG) was entered into a prospective study using bilateral near-infrared spectroscopy (NIRS) before anesthetic induction (T1), after anesthetic induction (T2), and continuing at 5-minute intervals during moderate hypothermic (32°C) CPB. Pump flows were set at 2.5 L/min/m(2) and adjusted to maintain mean arterial pressure (MAP) within 10 mmHg of the MAP recorded at the initial fifth minute of CPB (T3). Thirty-two patients were excluded from data collection because MAP could not be stabilized within the target range of 60-90 mmHg. In the remaining 94 patients, after obtaining steady state flow, MAP, and oxygenation, a trial period of hypocarbia (mean PaCO2 of 30 mmHg) was induced by increasing oxygenator fresh gas flow rate (FGFR) to 2.5 L/min/m(2) (T4). A reciprocal period was then measured at reduced FGFR (0.75 L/min/m(2)) (T5). RESULTS: After 20 minutes of a higher (2.75 L/min/m(2)) (FGFR), mean PaCO2 decreased from a baseline of 38 ± 4 mmHg to 30 ± 2 mmHg. This was associated with a parallel decrease (-10 ± 9%) in mixed cerebral oxygen saturation without alteration of mean arterial oxygen tension (PaO2), lactate, MAP, CPB flow, or other parameters implying increased cerebral oxygen extraction. CONCLUSION: Parallel changes in PaCO2 and rSO2 occur during CPB when other variables remain constant, and are due to the effects of carbon dioxide on cerebral arterioles. Cerebral oxygen saturation measured by NIRS may be a useful indirect measure of PaCO2 when continuous blood gas analysis is not possible during open-heart surgery. Cerebral oximetry values may be useful measurements for setting an optimum gas flow rate through the oxygenator.

The effect of mild left ventricular diastolic dysfunction on outcome after isolated coronary bypass surgery.

BACKGROUND: Although moderate to severe diastolic dysfunction (DD) seems to be associated with poor prognosis after isolated coronary bypass surgery, the impact of mild DD has not been investigated extensively in this group of patients. AIM: We evaluated the prognostic implication of mild left ventricular (LV) DD on outcome after isolated coronary bypass surgery in patients with preserved LV systolic function. METHODS: Data from 650 patients undergoing isolated coronary bypass surgery and having records for LV diastolic function between January 2009 and August 2011 was collected retrospectively. DD was classified as mild (grade 1, impaired relaxation), moderate (grade 2, decreased compliance) or severe (grade 3-4, restrictive pattern) depending on mitral inflow wave, tissue Doppler imaging, and pulmonary vein flow wave. Patients with baseline rhythm other than sinus, moderate or severe valvular dysfunction, moderate or severe diastolic dysfunction, and LV ejection fraction lower than 50% were excluded. A total of 472 patients were identified within the database fulfilling the eligibility criteria for this analysis and stratified according to the echocardiographic findings as follows: group 1 comprised patients with normal diastolic function (n = 168); and group 2 was made up of patients with mild DD (impaired relaxation) (n = 304). These groups were compared for perioperative morbidity and mortality. RESULTS: The preoperative variables were comparable between groups. The outcome parameters of group 1 was similar compared to group 2 in terms of need for inotropic support (20.2% vs. 16.2%), intra-aortic balloon pump usage (0% vs. 1.4%), mechanical ventilation time (8.94 ± 0.96 h vs. 10.0 ± 0.89 h), reintubation rate (1.8% vs. 1.4%), intensive care unit stay time (24.1 ± 1.4 hvs. 26.2 ± 1.9 h), postoperative renal failure rate (0% vs. 0.3%), postoperative atrial fibrillation rate (10.1% vs. 11.2%), length of hospital stay (7.19 ± 0.45 vs. 6.57 ± 0.14 days), hospital readmission rate (3.1% vs. 3.1%), and mortality (0% vs. 1.6%). CONCLUSIONS: The results from this study indicate that mild LV DD is not associated with adverse outcome after coronary bypass surgery in patients with preserved LV systolic function, thus should not be considered as a preoperative risk factor.

Readmission to the intensive care unit after fast-track cardiac surgery: an analysis of risk factors and outcome according to the type of operation.

INTRODUCTION: In the present study, we investigated risk factors for intensive care unit (ICU) readmission after fasttrack cardiac surgery and analyzed outcome data according to the type of surgical procedure. METHODS: Between 1999 and 2008, we prospectively enrolled 4270 consecutive patients who underwent isolated coronary artery bypass grafting (CABG) (CABG group, n = 3754), isolated valve surgery (valve group, n = 353), or combined CABG and valve surgery (CABG + valve group, n = 163) in the study. RESULTS: Ninety-eight patients (2.2%) were readmitted to the ICU. Of these patients, 73 were in the CABG group (1.9% of this group), 16 were in the valve group (4.5%), and 9 were in the CABG + valve group (5.5%). The main reason for ICU readmission in all groups was respiratory distress. A multivariate analysis showed that the independent risk factors for ICU readmission in the CABG group were an age >65 years (odds ratio [OR], 2.9; 95% confidence interval [CI], 1.5-5.4; P = .001), peripheral arterial disease (OR, 2.7; 95% CI, 1.2-6.1; P = .016), and drainage >500 mL (OR, 2.5; 95% CI, 1.2-5.1; P = .009). The independent risk factors for the valve group included only preoperative congestive heart failure (OR, 3.9; 95% CI, 1.3-11.7; P = .01). No independent risk factor was defined for the CABG + valve group. Mortality was significantly higher among the readmitted patients in all groups. CONCLUSIONS: The risk factors for readmission after cardiac surgery with fast-track recovery may differ according to the type of operation. A strict control of volume balance and blood transfusion may further help prevent the occurrence of the most frequent cause of readmission, respiratory failure.

Evaluation of risk factors associated with femoral pseudoaneurysms after cardiac catheterization.

BACKGROUND: Femoral pseudoaneurysm (FPA) is one of the common complications of percutaneous catheterization procedures performed via the femoral artery. The aim of this research was to evaluate factors associated with FPA of sufficient clinical significance that they required surgical treatment after diagnostic or interventional cardiac catheterization. METHODS: We evaluated 41,322 transfemoral catheterization procedures performed in our center within 7 years. Among all procedures, 630 FPAs developed that required surgical repair. Eighty-five cases were managed by compression with duplex guidance. As a case-control group, 1260 patients were selected from the patients who had been catheterized during the same time period but did not develop FPA. Two controls were selected for each study patient, matched according to age, sex, and catheterization day. Body mass index, hypertension, diabetes mellitus, catheter diameter, coronary artery disease, atherosclerosis, and number of cases performed per day in a particular room were evaluated as risk factors by using multivariate techniques. RESULTS: Femoral pseudoaneurysm required operative repair in 1.1% (n = 398) of patients who underwent cardiac catheterization for diagnostic purposes and in 4.7% (n = 232) of patients after cardiac interventional procedures. Factors found to be independently predictive of FPA were hypertension (P = .011; odds ratio, 1.52), diabetes mellitus (P = .035; odds ratio, 1.11), coronary artery disease (P = .022; odds ratio, 1.21), larger (> or = 28 kg/m2) body mass index (P < .001; odds ratio, 2.21), larger number of cases (> or = 18) performed per day in a particular room (P < .001; odds ratio, 2.39), and larger (> or = 7F) catheter diameter (P < .001; odds ratio, 2.82). CONCLUSIONS: Due to the development of technology and experience, more and more diagnostic and interventional catheterization procedures are performed on a daily basis. In our study, a high volume of cases in a particular room and use of large catheters were important risk factors for FPA complications. When these situations are combined with other risk factors (such as obesity, diabetes mellitus, hypertension, and arteriosclerosis), giving particular attention to local compression therapy would be more crucial to decrease the FPA rate.