Deep hypothermia with circulatory arrest. Determinants of stroke and early mortality in 656 patients.

We have retrospectively evaluated our results after aortic surgery in adults using deep hypothermia with circulatory arrest to determine the patient predictors of early death and postoperative stroke by logistic regression analysis. Of the 656 patients operated on between July 7, 1979, and January 30, 1991, 43% (n = 283) were female, the median age of the patients was 64 years (range 10 to 88 years), 12% (n = 77) had acute dissection, 26% (n = 173) had previously undergone either cardiac or ascending aortic operations, and 13% (n = 85) had a history of cerebrovascular disease. Eighty-four patients underwent elephant trunk procedures. The median circulatory arrest time was 31 minutes (range 7 to 120 minutes). The univariable predictors of transient or permanent stroke, defined as clinical evidence of neurologic injury, either global or hemiparetic, which occurred in 44 patients (7%), were as follows (p < 0.05): increased age; a history of cerebrovascular disease; circulatory arrest time (7 to 29 minutes = 12/298 [4%], 30 to 44 minutes = 15/201 [7.5%], 45 to 59 minutes 9/84 [10.7%], 60 to 120 minutes 7/48 [14.6%]; cardiopulmonary bypass time; and concurrent descending thoracic aorta repair. The multivariably determined predictors were as follows (p < 0.05): a history of cerebrovascular disease; previous aortic surgery distal to the left subclavian artery; and cardiopulmonary bypass time. A history of aortic valve incompetence, however, was associated with a lower risk of stroke (adjusted odds ratio 0.42, p = 0.015). The multivariably determined predictors for increased risk of early death (p < 0.05), which occurred in 66 (10%) patients, were as follows: increased age; Marfan syndrome; concurrent distal aortic aneurysm; previous ascending aortic operation; cardiopulmonary bypass time; cardiac complications; renal complications; and stroke. In this study, the occurrence of stroke was observed to increase after 40 minutes of circulatory arrest; furthermore, the mortality rate increased markedly after 65 minutes of circulatory arrest. Thus the "safe" period for strokes not developing appeared to be limited to approximately 40 minutes. We conclude that deep hypothermia with circulatory arrest is a safe technique for the repair of complex aortic problems provided both the circulatory arrest and the cardiopulmonary bypass times are not excessive. In addition, the clinical characteristics of the patients are important determinants of stroke and death.

Thoracoabdominal aortic aneurysm repair in a 15-month-old child.

This case report describes a young child with a thoracoabdominal aortic aneurysm, a very rare condition in pediatrics. The anesthetic management for resection of the aneurysm and repair of the aorta are presented, and special considerations for pediatric patients are discussed.

Continuous monitoring of mixed venous oxygen saturation during aortic surgery.

The correlation between mixed venous oxygen saturation (SvO2) and hemodynamic measurements was studied in 13 patients undergoing descending thoracic aortic aneurysm resection (DTAAR). A significant correlation (p less than 0.05) was found between cardiac index (CI) and SvO2 after the induction of anesthesia and at the end of surgery. However, no significant correlation could be found between SvO2 and CI during the most critical periods of the surgery that included the collapse of the left lung, the aortic clamping, and the aortic declamping. During DTAAR, continuous SvO2 monitoring is useful, but it cannot substitute for intermittent cardiac output and oxygen consumption (VO2) determinations.

[Anesthesia for the surgery of the thoracic and thoraco-abdominal aorta]. / Anesthésie pour la chirurgie de l'aorte thoracique et thoraco-abdominale.

Haemodynamic monitoring, anaesthetic technique and perioperative management were reported for a series of 317 consecutive patients who underwent graft replacement of descending thoracic or thoracoabdominal aortic aneurysms at the Baylor College of Medicine, Houston (Texas) between january 1979 and june 1982. The surgical technique used was aortic clamping without shunt. The anaesthetic technique combined high dose fentanyl (50-100 micrograms X kg-1), oxygen ventilation, pancuronium bromide and vascular filing. The patients were monitored by Swan-Ganz catheters. The systemic blood pressure increased by 8% during the clamping of the aorta in spite of the use of sodium nitroprussiate, whereas the systemic vascular resistances did not increase significantly. The cardiac output increased by 19%, whereas the heart rate remained stable. After unclamping, the systemic blood pressure did not decrease significantly, whereas the systemic vascular resistances fell by 20%; the cardiac output increased by 64%, whereas the heart rate remained stable. The 30-day mortality was 10% (32 patients). Four of them died during surgery. The postoperative morbidity included 33 cases of paraplegia and paraparesis, 31 cases of renal insufficiency and 28 cases of postoperative pulmonary complications. The prevention of the consequences of aortic clamping and the management of the hypoxaemia occurring during one lung anaesthesia are discussed.

Effect of profound hypothermia on leukocytes and platelets.

Seventeen patients who underwent aortic arch replacement were subjected to profound hypothermia and circulatory arrest. At maximum cooling, platelet count dropped from 184 +/- 122 to 37 +/- 30 thousand per microliter, and the total leukocytic count fell from 6.27 +/- 4.0 to 1.47 +/- 0.6 thousand per microliter. The thrombocytopenia was partially reversed with rewarming. The total white cell count consistently returned to precooling values or higher (10.5 +/- 4.0). The mechanism for this cold induced phenomenon is not well understood.

Unusual complication of Swan-Ganz catheter requiring mediastinotomy.

We were consulted to assist in the removal of an anchored Swan-Ganz catheter. After failing in several attempts to remove the catheter, we elected to return the patient to the operating room in the event that the catheter had been sutured to the right atrium. No evidence of this was found. We believe the catheter was anchored to the pulmonary bed, but the definite cause of this problem is still obscure.

Use of nitroprusside during surgery for thoracoabdominal aortic aneurysm.

To assess the effects of sodium nitroprusside on the deleterious hemodynamic effects of clamping and unclamping of the aorta during resection of thoracoabdominal aortic aneurysm without the use of a shunt, 50 patients were studied. The risk factors included coronary artery disease (44%) associated with previous myocardial infarction (28%), hypertension (70%), congestive heart failure (6%), chronic obstructive pulmonary disease (34%), asthma (2%), and renal insufficiency (2%). Sodium nitroprusside infusion (3 micrograms/kg/min) was started before clamping and discontinued before unclamping of the aorta. The infusion rate was adjusted to maintain blood pressure and pulmonary capillary wedge pressure within the range of control. During cross-clamping cardiac index in the patients remained unchanged and even increased on unclamping, suggesting that left ventricular function was efficiently protected during these periods. All the patients survived the surgery, and the 30 day mortality was only 4%. Our data indicate that major aortic surgery can be carried out safely with the use of nitroprusside rather than of mechanical techniques to provide proximal decompression.