Increasing mean arterial pressure improves jugular venous oxygen saturation in patients with and without preexisting stroke during normothermic cardiopulmonary bypass

Changes in jugular bulb oxygen saturation during off-pump coronary artery bypass graft surgery

BACKGROUND

The effect of haemodynamic derangement during coronary artery anastomosis in off-pump coronary artery bypass surgery on cerebral blood flow has not been elucidated. Jugular bulb oxygen saturation is a useful indicator of cerebral blood flow provided that the cerebral metabolic rate is constant. This study was designed to evaluate the changes in jugular bulb oxygen saturation during off-pump coronary artery bypass surgery.

METHODS

With IRB approval, 48 patients were included. After anaesthesia, an 18-G catheter was introduced into the jugular bulb. Haemodynamic variables and oxygen profiles from gas analysis of jugular bulb blood and arterial blood were obtained: after sternotomy (baseline); at 5 min after the beginning of the anastomosis of the left anterior descending artery, obtuse marginal artery, and right coronary artery; and after sternal closure.

RESULTS

Cardiac index and mixed venous oxygen saturation decreased significantly during anastomosis of all three arteries compared to the baseline value. Although the changes in jugular bulb oxygen saturation during anastomosis were statistically significant compared to its baseline value, jugular bulb oxygen saturation remained within normal limit throughout the study.

CONCLUSIONS

Jugular bulb oxygen saturation, which represents the global cerebral oxygenation, was well maintained during the anastomosis of all coronary arteries despite significant haemodynamic changes during off-pump coronary artery bypass (OPCAB).

Selective Use of Off-Pump Coronary Bypass Surgery Reduces Mortality and Neurologic Morbidity Associated with High-Risk Coronary Bypass Surgery: A 400-Case Comparative Experience

The frequency of use of off-pump coronary artery bypass (CAB) surgery to surgically treat coronary artery disease has varied greatly from center to center and from surgeon to surgeon because of preference, training, and experience. We report an experience with 400 consecutive isolated CAB procedures selectively managed with on-pump or off-pump surgery, according to the perceived potential for aortic embolization or stroke as determined by clinical and imaging determinations. The off-pump CAB group (46 patients) was 7.1 years older (P < .05) and had an 11% lower ejection fraction (P < .03) than the on-pump group. There was no difference in gender, urgency of surgery, hemodynamic stability, angina class, or incidence of prior myocardial infarction. All 400 patients underwent intraoperative transesophageal echocardiography, and many underwent an epiaortic study to supplement image quality. Patients without palpable or imaged advanced aortic disease or deemed to be at clinically high risk for stroke (advanced age, prior strokes, or advanced cerebrovascular or peripheral vascular disease) underwent on-pump procedures requiring 55 minutes of aortic ischemia and 97 minutes of high-flow, high-pressure bypass on average. All others underwent off-pump procedures. The numbers of grafts per patient were similar (3.2 on-pump, 2.8 off-pump; = ns). There was no in-hospital or 30-day mortality in either group. Using the New York State risk-adjustment algorithm, we found the predicted mortality rate for the off-pump group was higher (2.24% on-pump versus 5.54% off-pump, P = .008). The postoperative length of stay was longer in the off-bypass group (3.67 days versus 4.31 days, P = .003). The frequencies of hospital readmission and perioperative complications (renal, pulmonary, infection, bleeding, cardiac, neurologic) were similar, and there were no postoperative strokes in either group. The selective use of off-pump surgery safely managed patients at higher risk for perioperative stroke and associated embolic multisystem organ failure and death. Individual surgeon and center-wide use of a selective approach is recommended as an alternative to a single-procedure nonselective approaches.

Cerebrovascular carbon dioxide reactivity with propofol anesthesia in patients with previous stroke

STUDY OBJECTIVE

To examine whether patients with previous stroke have impaired cerebrovascular carbon dioxide (CO2) reactivity when receiving propofol anesthesia.

DESIGN

Prospective, controlled study.

SETTING

University hospital.

PATIENTS

34 consecutive patients, 17 of whom had previous stroke and were scheduled for elective cardiac surgery, and 17 control age-matched patients without previous stroke who were also scheduled for cardiac surgery.

INTERVENTIONS

Anesthesia was induced and a 2.5-MHz pulsed transcranial Doppler probe was attached to the patient's head at the right temporal window. Mean blood flow velocity of the middle cerebral artery (Vmca) was measured continuously.

MEASUREMENTS

After establishing baseline Vmca, arterial blood gases and cardiovascular hemodynamic values, partial pressure of end-tidal CO2 (PETCO2) was increased by changing the ventilatory frequency by 2 to 5 breaths/min. The measurements were repeated when PETCO2 increased and remained stable for 5 to 10 minutes.

MAIN RESULTS

Values for absolute CO2 reactivity in the control patients and in those with previous stroke were 2.6 +/- 0.5 and 2.9 +/- 0.7 cm/sec/mmHg, respectively, a nonsignificant difference in these values. Values for relative CO2 reactivity in control patients and in patients with previous stroke were 6.4 +/- 1.4 and 6.1 +/- 1.4%/mmHg, respectively, with no significant difference noted.

CONCLUSIONS

Cerebrovascular CO2 reactivity in patients with previous stroke is normal during propofol anesthesia.