From January 1, 1988 to September 30, 1993, 44 of 2,455 patients undergoing cardiac surgery for acquired heart disease at our institution sustained an intraoperative or postoperative cerebrovascular accident (CVA). Demographic data, atherosclerosis risk factors, past medical history, cardiac catheterization reports, and intraoperative findings were retrospectively reviewed. The highest rate of CVA was in the sub-group of patients undergoing simultaneous myocardial revascularization and carotid endarterectomy (18.2%). The lowest rate was in a group of patients who underwent aortic valve replacement (0.9%). Severe aortic arch atherosclerosis with the presence of atheromatous material or calcinosis at the cannulation site was identified intraoperatively in 43.2% of patients with neurological complications and in 5% of the group without CVA (x2 = 18.1, p = 0.0001). Of 44 patients with CVA, 13.6% had a history of preoperative completed stroke. CPB time was 90.1 +/- 4.9 min vs. 71.6 +/- 3.7 min (p = 0.004), and aortic cross-clamping time was 54.5 +/- 3.2 min compared to 39.8 +/- 2.7 min (p = 0.001) in groups with and without postoperative stroke, respectively. Hypertension was an independent risk factor of postoperative CVA (x2 = 9.5, p = 0.02), but age was not. Neurological complications correlated with high operative mortality (38.6%) and prolonged postoperative hospital stays (35.1 +/- 5.3). These data describe predictors for the development of post-cardiopulmonary bypass CVA and identify a high-risk subgroup for neurological events. The preoperative recognition of risk factors is an essential step toward the reduction of morbidity and mortality.

Traumatic vascular injury in the thoracocervical region is associated with significant morbidity and mortality. The goal of this study was to examine surgical outcome of these injuries and to establish predictors of survival. The medical records of all patients sustaining traumatic injury to the carotid, vertebral, subclavian, and proximal axillary vessels and undergoing operative repair were retrospectively reviewed. Sixteen patients (11 men, 5 women, mean age 31.1 ±16.6) during a four-year period underwent emergent surgical repair for traumatic vascular disruption. There were 6 lesions of the carotid, 7 of the subclavian, and 2 of the proximal axillary vessels and 1 vertebral artery injury. Sixty- two percent of the patients were hemodynamically unstable on admission. In these patients the diagnosis was established by clinical examination. Hemodynamically stable patients with a high index of suspicion for vascular injury underwent urgent arteriog raphy to confirm the diagnosis and assist in the operative approach. Surgical procedures included lateral arteriorrhaphy (2), end-to-end anastomoses (2), synthetic interposition grafts (3), and autogenous vein graft (2). Seven patients underwent emergent ligation of the subclavian, carotid, or vertebral artery. Despite 3 of 16 patients presenting in either unresponsive shock or with severe head trauma, overall mortality was 25%. Nonsurvivors had significantly higher injury severity scores than survivors (36.3 ±13.1 vs 19.8 ±7.9, P < 0.05). Length of time from trauma scene to hospital was a significant predictor of survival (33.4 ± 13.3 vs 50.8 ±6.5 minutes) as was the presence of associated organ system injury (2.8 ±0.9 organ systems vs 4.3 ±0.9, P < 0.05) in survivors and nonsur vivors, respectively. No neurologic compromise or limb ischemia was noted in the group undergoing arterial ligation. Among similarly injured vessels, the type of surgical repair did not influence patient survival. The outcome of surgical repair of a traumatic lesion of the thoracocervical vessels depends upon the rapid recognition of the injury, time delay to the trauma unit, and the magnitude of associated injury.

To examine the effect of a low dose of Oxygent HT on hemodynamics and oxygen transport variables in a canine model of profound surgical hemodilution, two groups of adult anesthetized splenectomized beagles were hemodiluted with Ringer's solution to Hb 7 g/dL. The treated group received 1 mL/kg Oxygent HT (90% w/v perflubron emulsion [perfluorooctyl bromide], Alliance Pharmaceutical Corp.) and both groups (7 controls and 10 treated) were further hemodiluted using 6% hydroxyethyl starch until cardiorespiratory decompensation occurred. Pulmonary artery catheterization data and oxygen transport variables were recorded at Hb decrements of 1 g/dL breathing room air. There was no difference among groups during initial hemodilution. However, in the Oxygent HT group there was a statistically significant improvement in mean arterial pressure, CVP, cardiac output, PvO2, SvO2, DO2, and pulmonary venous admixture shunt during profound hemodilution to Hb levels of 6, 5, and 4 g/dL. A low dose of Oxygent HT offered benefit in improving hemodynamics and oxygen transport parameters even under air breathing conditions in a model of surgical hemodilution. This effect was most apparent at lower levels of Hb.

Sedation and anxiolysis with lorazepam and midazolam in critically ill patients is safe and clinically effective. Hemodynamic and oxygen transport variables are similarly affected by both drugs. The dose of midazolam required for sedation is much larger than the dose of lorazepam required for sedation, and midazolam is therefore less cost-efficient.