Reef islands have continually adjusted to environmental change over the past two millennia.

Global environmental change is identified as a driver of physical transformation of coral reef islands over the past half-century, and next 100 years, posing major adaptation challenges to island nations. Here we resolve whether these recent documented changes in islands are unprecedented compared with the pre-industrial era. We utilise radiometric dating, geological, and remote sensing techniques to document the dynamics of a Maldivian reef island at millennial to decadal timescales. Results show the magnitude of island change over the past half-century (±40 m movement) is not unprecedented compared with paleo-dynamic evidence that reveals large-scale changes in island dimension, shape, beach levels, as well as positional changes of ±200 m since island formation ~1,500 years ago. Results highlight the value of a multi-temporal methodological approach to gain a deeper understanding of the dynamic trajectories of reef islands, to support development of adaptation strategies at timeframes relevant to human security.

Effects of spinal anesthesia on response to main pulmonary arterial distension.

Nonocclusive main pulmonary arterial distension produces peripheral pulmonary hypertension. The mechanism of this response is unknown. The effects of total spinal anesthesia on the response were studied in halothane-anesthetized dogs. Before total spinal anesthesia, main pulmonary arterial balloon inflation increased pulmonary arterial pressure and resistance without affecting systemic hemodynamic variables. Both right and left pulmonary arterial pressures were monitored to exclude unilateral obstruction with main pulmonary arterial balloon inflation. Total spinal anesthesia decreased cardiac output and systemic arterial pressures. After total spinal anesthesia, main pulmonary arterial distension still increased pulmonary arterial pressure and resistance. Right atrial pacing, discontinuation of halothane anesthesia, and norepinephrine infusion during total spinal anesthesia partially reversed the hemodynamic changes caused by total spinal anesthesia. The percent increase in pulmonary vascular resistance due to main pulmonary arterial distension was similar before total spinal anesthesia and during all experimental conditions during total spinal anesthesia. The pulmonary hypertensive response is therefore not dependent on central synaptic connections.

Metaanalysis of prophylactic drug treatment in the prevention of postoperative bleeding.

Prophylactic drug treatment is one of several strategies to reduce postoperative blood loss and potentially limit homologous blood use in open heart surgery. A computerized MEDLINE search supplemented with manual bibliography reviews was performed for randomized clinical trials published in peer-reviewed English-language journals from January 1980 to June 1993. A metaanalysis was conducted of trials evaluating desmopressin (group DD, n = 13), epsilon-aminocaproic acid or tranexamic acid (group EA, n = 4), and aprotinin (group AP, n = 16). Eligible studies used placebo controls and administered the drug in a prophylactic manner. The primary study end point was postoperative chest tube loss (mL, mean +/- standard deviation). There was a significant reduction in postoperative chest tube loss detected for each of the active treatments versus the placebo (DD versus controls: percent reduction 0.11, p = 0.0021; EA versus controls: percent reduction 0.30, p < 0.0001; and AP versus controls: percent reduction 0.36, p < 0.0001). Therapy with EA or AP was associated with a greater reduction in chest tube loss than DD (EA versus DD, p = 0.0033, and AP versus DD, p < 0.0001). Secondary study end points were transfusion requirements, chest reexploration, and perioperative mortality. The volume of postoperative red cell transfusion (mean +/- standard deviation) was reduced with EA (p < 0.0001) or AP treatment (p < 0.0001) compared with a placebo or DD, whereas the proportion of patients given transfusions was limited only in the AP-treated patients (odds ratio 0.23; 95% confidence interval, 0.16 to 0.33; p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aprotinin and tranexamic acid for high transfusion risk cardiac surgery.

BACKGROUND: Studies have shown that aprotinin and tranexamic acid can reduce postoperative blood loss after cardiac operation. However, which drug is more efficacious in a higher risk surgical group of patients, has yet to be defined in a randomized study. METHODS: With informed consent, 80 patients undergoing elective high transfusion risk cardiac procedures (repeat sternotomy, multiple valve, combined procedures, or aortic arch operation) were randomized in a double-blind fashion, to receive either high dose aprotinin or tranexamic acid. Patient and operative characteristics, chest tube drainage and transfusion requirements were recorded. RESULTS: There was no significant difference between the 2 treatment groups with respect to age, cardiopulmonary bypass time, complications (myocardial infarction, stroke, death), chest tube drainage (6, 12, or 24 hours), blood transfusions up to 24 hours postoperatively, total allogeneic blood transfusions for entire hospital stay, or induction/postoperative hemoglobin levels. However, multiple regression analysis revealed a positive relationship between cardiopulmonary bypass time and 24 hour blood loss in the tranexamic acid group (p = 0.001), unlike the aprotinin group where 24 hour blood loss is independent of cardiopulmonary bypass time (p = 0.423). CONCLUSIONS: Overall, there was no significant difference in blood loss, or transfusion requirements, when patients received either aprotinin or tranexamic acid for high transfusion risk cardiac operation. Aprotinin, when given as an infusion in a high-dose regimen, was able to negate the usual positive effect of cardiopulmonary bypass time on chest tube blood loss.

Cardiopulmonary bypass, rewarming, and central nervous system dysfunction.

BACKGROUND: During cardiopulmonary bypass a nasopharyngeal temperature greater than 38 degrees C at the end of rewarming may indicate cerebral hyperthermia. This could exacerbate an ischemic brain injury incurred during cardiopulmonary bypass. METHODS: In a cohort of 150 aortocoronary bypass patients neuropsychologic test scores of 66 patients whose rewarming temperature exceeded 38 degrees C were compared with those who did not. There were no differences between groups with respect to demographic and intraoperative variables. RESULTS: A trend was seen for hyperthermic patients to do worse on all neuropsychologic tests in the early postoperative period but not at 3-month follow-up. By analysis of covariance hyperthermic patients did worse on the visual reproduction subtest of the Weschler memory scale at 3 months (p = 0.02), but this difference was not found by linear regression (p = 0.10). CONCLUSIONS: We were unable to demonstrate any significant deterioration in patients rewarmed to greater than 38 degrees C in the early postoperative period. The poorer performance in the visual reproduction subtest of the Wechsler memory scale at 3 months in the group rewarmed to more than 38 degrees C is interesting but far from conclusive. Caution with rewarming is still advised pending more in-depth study of this issue.

Normothermic versus hypothermic cardiopulmonary bypass: central nervous system outcomes.

The recent advent of "warm heart" surgery has resulted in reexamination of the neuroprotective effects of hypothermia in the setting of cardiopulmonary bypass (CPB). Hypothermia has been shown to confer significant protection in the setting of transient, but not permanent, ischemia. The mechanism of this neuroprotection is unclear at this time. Reduction in cerebral metabolic rate is believed to be less important compared with the effect of hypothermia on the release of excitatory neurotransmitters, catecholamines, or other mediators of cellular injury. It is for this reason that mild hypothermia (33-35 degrees C) is believed to confer significant neuroprotection. Two large randomized trials of warm versus cold heart surgery have been reported. Neither study found a difference in terms of neuropsychologic dysfunction. However, one study identified a threefold increase in strokes in the "warm" patients. The reasons for this difference are not clear; however, there were various differences in technique and patient population that may have been important. There are other reports of large series of patients undergoing normothermic bypass, with no increase in stroke rate over what is reported elsewhere in the literature. To date, the evidence would suggest that neuropsychologic function is not affected by CPB temperature, suggesting that the transient ischemia is not an important mechanism in this injury. Stroke after CPB is usually the result of permanent ischemia, and hypothermia's effect in this setting is minimal. It would seem unlikely that hypothermia offers anything more than modest benefits in the clinical situation where there is no circulatory arrest.

Anaesthetic management of acute blunt thoracic trauma.

Sunnybrook Health Science Centre is an adult regional trauma unit serving metropolitan Toronto and environs. We undertook a two-year retrospective review of patients admitted to our institution with blunt thoracic trauma. Three hundred and thirty-three patients with blunt trauma and an injury severity score (ISS) greater than 17 required emergency surgery. Of these, 208 had blunt thoracic injuries while 125 did not have chest injuries. Both groups were similar with respect to age but patients with thoracic trauma had a greater ISS. (P less than 0.05) and greater intraoperative mortality (P less than 0.01). The aetiology of the intraoperative deaths with one exception was exsanguination. Emergency thoracotomy or sternotomy indicated a poor prognosis with a mortality rate of 80%. The most common intraoperative problem was an elevated airway pressure. Awake intubation was undertaken in 77.5% of patients requiring anaesthesia and surgery because of the potentially compromised airways and difficult intubations due to the nature of the associated injuries. Finally, 74% of patients undergoing urgent surgery required mechanical postoperative ventilation. The presence of blunt chest trauma should be considered a marker of the severity of injury sustained by the patient.

Pulmonary pressures at high flows in the intact pulsatile flow perfused lung.

Pulmonary pressure-flow curves can be easily generated in the intact animal by using a combination of systemic arteriovenous (a-v) fistulas and inferior vena cava (IVC) occlusion. By combining this technique with pulmonary artery occlusion, pulmonary pressure-flow curves may be studied over a broader range of pressures than has been previously been done in the intact, resting animal using pulsatile flow. Pressure-flow curves were generated by varying flow through opening and closing of the a-v fistulas in conjunction with inflating and deflating a balloon in the inferior vena cava. The pressure-flow curves were done under two conditions; (1) with both lungs perfused; (2) with the right lung excluded from the circulation (PA occlusion). PA occlusion resulted in no change in alveolar arterial oxygen tension gradient. The pressure-flow relationships for one lung and two lungs were well described by linear equations (r2 = 0.83 +/- 0.03 and 0.82 +/- 0.04 respectively). The slope of the equations increased with PA occlusion (3.6 +/- 0.4 mmHg.L-1 to 5.9 +/- 0.9 mmHg.L-1). There was no change in the pressure axis intercept with PA occlusion (8.34 +/- 0.8 mmHg pre-occlusion and 8.9 +/- 1.3 mmHg post-occlusion). It is concluded that the pulmonary pressure-flow relationship is well described by a linear function above a mean pulmonary artery pressure (PAP) of 10-12 mmHg.

Perioperative cardiovascular complications associated with blunt thoracic trauma.

The purpose of this study was to examine the frequency and importance of intraoperative mortality, arrhythmias and hypotension in the presence of thoracic trauma and to determine the effect of myocardial contusion on these perioperative complications. Over a two-year period patients with evidence of blunt thoracic injury who required surgery within 24 hr of admission were studied. The anaesthetist filled in a questionnaire on intraoperative events. Patients were also studied for the presence of myocardial injury with radionuclide angiography (RNA), at autopsy or at thoracotomy. Two hundred and one patients were studied. The intraoperative and overall mortality was 7.9% and 22.9% respectively. Of the operating room survivors the incidence of intraoperative arrhythmias and hypotension was 3.8% and 26.5% respectively. Only 5.9% of patients had a suspected or confirmed myocardial contusion. Patients were divided into two groups, those without myocardial injury were designated Group I, while those with myocardial contusion were designated Group II. The Group II patients had a greater severity of injury and intraoperative mortality (54.4%) than those in Group I (4.6%) P < 0.05. Intraoperative deaths were attributed to, with one exception, non-cardiac causes. There were no differences in the incidences of arrhythmias and hypotension between patients with-or without myocardial injury surviving the operating room. All patients with blunt thoracic injury may develop intraoperative arrhythmias or hypotension.

Vasodilator therapy in microembolic porcine pulmonary hypertension.

The hemodynamic effects of prostaglandin E1, sodium nitroprusside (SNP), nitroglycerin, and hydralazine were studied in a porcine model of elevated pulmonary vascular resistance (PVR) due to glass bead microembolization (60-150-microns diameter). Each animal received all four drugs. Each drug was titrated to produce a 30% reduction in mean systemic arterial pressure. Although all four drugs decreased PVR, distinct differences in the hemodynamic profiles of the four drugs were evident. Prostaglandin E1 produced the largest reduction in mean pulmonary artery pressure (from 41 +/- 1 to 32 +/- 9 mm Hg, mean +/- SEM) and PVR (25 +/- 3 to 18 +/- 2 mm Hg.L-1.min-1), and did not affect the ratio of PVR to systemic vascular resistance (PVR/SVR). Sodium nitroprusside and nitroglycerin produced moderate decreases in PVR (nitroglycerin 21 +/- 2 to 18 +/- 2 mm Hg.L-1.min-1, SNP 22 +/- 2 to 19 +/- 2 mm Hg.L-1.min-1) and in mean pulmonary artery pressure (nitroglycerin 39 +/- 1 to 35 +/- 1; SNP 40 +/- 1 to 36 +/- 2 mm Hg). Both drugs significantly increased the PVR/SVR ratio. Hydralazine was the only drug that significantly increased cardiac output (1.6 +/- 0.2 to 1.9 +/- 0.3 L/min). Hydralazine had no significant effect on mean pulmonary artery pressure, reduced PVR to the smallest extent (11%), and resulted in the largest increase in the PVR/SVR ratio (from 0.52 +/- 0.04 to 0.80 +/- 0.08). In this model of increased pulmonary vasculature resistance prostaglandin E1 caused an equivalent amount of pulmonary and systemic vasodilation, as expressed by the PVR/SVR ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Incidence of abnormal RNA studies and dysrhythmias in patients with blunt chest trauma.

The incidence and significance of myocardial contusion and subsequent cardiac complications have recently been debated. A prospective study of patients with blunt chest trauma was undertaken at a Regional Trauma Unit between January 1, 1989 and March 31, 1990. One hundred ninety-one patients were entered into the study; 72-hour Holter monitoring was performed in 183 patients, and radionuclide angiography (RNA) was performed on 163 patients. All patients had CPK levels (with CPK-mb fractions) measured, and serial electrocardiographs. There were seven patients with abnormal RNA studies; five of the seven abnormal studies were attributable to previously undiagnosed coronary artery disease or myocardial infarction. Nine patients were diagnosed as having atrial fibrillation, seven of whom were in atrial fibrillation on admission. Ventricular dysrhythmias were classified by the number of premature ventricular contractions (PVCs) per hour or the presence of ventricular tachycardia. Twelve patients developed short runs of ventricular tachycardia, and clinically insignificant PVCs were common. Only one patient with ventricular dysrhythmias (frequent PVCs) was treated and there were no hemodynamically significant dysrhythmias. The incidence of clinically significant dysrhythmias or hemodynamically significant myocardial contusion appears to be low in this patient population. Aggressive investigation and monitoring solely for cardiac complications may not be indicated.

Recall of intraoperative events after general anaesthesia and cardiopulmonary bypass.

We wished to identify patients able to recall intraoperative events after general anaesthesia involving cardiopulmonary bypass (CPB). A balanced anaesthetic technique consisting of benzodiazepines, low dose fentanyl (15.9 +/- 8.5 micrograms.kg-1) and a volatile agent was employed. Perioperative recall was sought utilizing a structured interview on the fourth or fifth postoperative day. During 20 mo 837 patients underwent CPB. Seven hundred patients (84%) were able to respond to a structured postoperative interview. A detailed chart review was performed in patients with recall and in 60 randomly selected patients without recall. Eight patients (1.14%) reported recall of intraoperative events. We were unable to identify any differences between the two groups with respect to narcotic, benzodiazepine dosage or usage of inhalational agents. The incidence of recall in patients undergoing cardiac surgery was less in our group than previously reported. It is, however, higher than the 0.2% incidence recently reported in patients undergoing non-cardiac surgery. This is probably due to patient characteristics and intraoperative factors which make it difficult to avoid periods of relatively light anaesthesia during cardiac surgery.

What are the clinical determinants of early energy expenditure in critically injured adults?

The clinical determinants of energy expenditure in critically injured adults require definition. Among adult blunt trauma victims who required mechanical ventilation, the resting energy expenditure was calculated with the Harris-Benedict equation (HBEE) and the early (< or = 5 days postinjury) energy expenditure was measured by indirect calorimetry (MEE) (n = 115). The MEE was 2052 +/- 531 kcal/day and MEE/HBEE ("stress factor") was 1.24 +/- 0.2. The MEE was correlated with HBEE, age, height, weight, sex, temperature, and paralytic agents (p < 0.01). However, MEE did not correlate with ISS, admission GCS score, admission base deficit, initial systolic blood pressure, or the number of units of packed red blood cells transfused in the first 24 hours after injury (p = NS). Temperature and paralysis correlated with MEE/HBEE (p < 0.01). A regression model of MEE was developed with the clinical variables HBEE, temperature, and the presence or absence of paralytic agents (r2 = 0.62; p < 0.001): MEE (kcal/d) = 1.4(HBEE) + 71.4(temperature) + 274(paralytics; + = 1, - = 2) - 3485. In mechanically ventilated trauma victims, both the early energy expenditure and the stress factor are determined by host factors but are independent of the severity of the anatomic and physiologic insult. The degree of hypermetabolism observed in this population was less than previously reported.

Death in two Canadian intensive care units: institutional difference and changes over time.

OBJECTIVE: To study and compare the mode of death in two different institutions' intensive care units (ICUs) for the two time periods, 1988 and 1993. DESIGN: Retrospective chart review. SETTING: Medical/surgical/trauma ICUs in two tertiary care teaching hospitals. PATIENTS: Patients dying in the medical/surgical/trauma ICUs between January 1, 1988 and December 31, 1988; and January 1, 1993 and December 31, 1993. Data collection included demographics, origin of admission, date of ICU admission, date of death, Acute Physiology and Chronic Health Evaluation (APACHE) III diagnostic categories, APACHE II physiologic variables, organ system failures present at the time of admission and 24 hrs before death, and mode of dying. APACHE II scores and mortality risk were calculated. Data analysis included a multiple analysis of variance to assess overall effect, with subsequent analyses of variance to assess the effect of institution and year on each individual dependent variable. All results are reported as mean +/- SEM values. RESULTS: A total of 439 charts were reviewed. Gender, age, and origin of admission were not different between the 2 yrs or the two institutions. Mean APACHE II scores and organ system failures were lower at Hospital A in 1998 vs. Hospital B, as was predicted mortality. These factors increased at Hospital A in 1993 and were similar to those at Hospital B. Withdrawal of support was much more common in 1993 than 1988 at both institutions (43% at Hospital A and 46% at Hospital B in 1988 vs. 66% at A and 80% at B in 1993), increasing to a greater extent in 1993 at Hospital B (p<.05). Length of stay in the ICU was significantly longer at Hospital A than at Hospital B in 1988 (9.4+/-1.4 vs. 4.3+/-0.6 days; p<.05) and in 1993 (8.2+/-2.9 vs. 3.8+/-0.5 days; p < .05). CONCLUSIONS: There has been an increase in withdrawal of life support, in recent years, at both the institutions studied. Differences exist between institutions with respect to end-of-life decisions in the ICU. These differences are likely representative of widely prevalent regional differences and are the result of many factors.

Is clinical examination an accurate indicator of raised intra-abdominal pressure in critically injured patients?

OBJECTIVES: To determine the rate of elevated intra-abdominal pressure (IAP) and to evaluate the accuracy of clinical abdominal examination in the assessment of IAP in the critically injured trauma patient. DESIGN: A prospective blinded study. SETTING: The medical-surgical critical care unit of a university-affiliated regional adult trauma centre. PATIENTS: Forty-two adult blunt trauma victims, who had a mean injury severity score of 36. INTERVENTIONS: Urinary bladder pressure was measured daily and classified as normal (10 mm Hg or less), elevated (more than 10 mm Hg) or significantly elevated (more than 15 mm Hg). A blinded clinical assessment of abdominal pressure was concurrently performed and recorded as elevated or normal. MAIN OUTCOME MEASURES: The sensitivity, specificity and accuracy and the positive and negative predictive values of the 2 interventions in identifying elevated IAP. RESULTS: Twenty-one patients (50%) had an elevated IAP at some point during the study. Of the 147 bladder pressure measurements done in these 42 patients, 47 (32%) were more than 10 mm Hg and 16 (11%) were more than 15 mm Hg. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of clinical abdominal examination for identifying elevated IAP were 40%, 94%, 76%, 77% and 77%, respectively. Clinical abdominal examination had a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 56%, 87%, 35%, 94% and 84% respectively, for significantly elevated IAP. CONCLUSIONS: Urinary bladder pressure was commonly elevated among our population of critically injured adults. Compared with bladder pressure measurements, clinical abdominal assessment showed poor sensitivity and accuracy for elevated IAP. These findings suggest that more routine measurements of bladder pressure in patients at risk for intra-abdominal hypertension should be performed.

Outcome of respiratory intensive care for the elderly.

We followed 1018 patients admitted consecutively to a multidisciplinary respiratory ICU (RICU), with special attention to patients aged 75 yr and over. The elderly had a higher RICU (11/49) and in-hospital (21/49) mortality than younger patients. The 28 survivors of hospitalization had a lower acute physiology score (APS) than nonsurvivors on admission (16.1 +/- 7.8 vs. 21.8 +/- 8.9, respectively), indicating less severe illness. The quality of long-term survival (12 to 24 months) was assessed using an open-ended questionnaire. Eighteen hospital survivors were alive at the time of follow-up and the quality of life was deemed satisfactory by 10 of 13 patients who were living independently. Only two of 28 survivors had been transferred to nursing home care, and two were in acute care hospitals. We conclude most elderly patients discharged from the RICU consider their lifestyle satisfactory and are not a large drain on community health care resources. Further studies of the screening process which determines RICU admission are necessary, because unimodal criteria such as age and APS after admission were not of prognostic value.

Significance of myocardial contusion following blunt chest trauma.

A prospective study was undertaken at a regional trauma unit (RTU) to determine the significance of cardiac complications in patients with blunt chest trauma. Radionuclide angiographic (RNA) imaging was performed as soon as possible after admission and Holter monitors were applied for 72 hours. Routine investigations included serial cardiac enzyme measurements and 12-lead electrocardiograms. Dysrhythmias were classified and ventricular dysrhythmias were stratified by ventricular ectopic score (VES) as ventricular tachycardia (4) or greater than 100 premature ventricular contractions (PVCs)/hour (3). Three hundred twelve patients were entered into the study. Analysis of dysrhythmias revealed 18 patients with a VES of 4 and nine patients with a VES of 3; there were no serious consequences. The most significant dysrhythmia as a marker of outcome was atrial fibrillation (n = 9); five of these patients died, but all of associated noncardiac injuries. A review of abnormal RNAs revealed that all associated mortalities were attributed to noncardiac injuries. A review of postmortem reports and hospital records revealed that no deaths were attributed to cardiac failure or dysrhythmia. Thus the incidence of clinically significant dysrhythmias or other cardiac complications resulting from blunt trauma to the heart may be overestimated.

Ketamine concentrations during cardiopulmonary bypass.

PURPOSE: To describe the serum concentrations of ketamine following a clinically relevant dosing schedule during cardiopulmonary bypass (CPB). DESIGN: Prospective case series. SETTING: Tertiary care teaching hospital. PATIENTS: Six patients undergoing coronary artery bypass grafting and over age 60 yr. INTERVENTION: Following induction of anaesthesia each patient received a bolus of ketamine 2 mg.kg-1 followed by an infusion of 50 micrograms.kg-1.min-1 which ran continuously until two hours after bypass. MAIN OUTCOME MEASURES: Ketamine serum concentrations were measured at five minutes after bolus, immediately following aortic cannulation, 10 and 20 min on CPB, termination of CPB, termination of the drug infusion and three and six hours after infusion termination. RESULTS: At the time of aortic cannulation, ketamine concentrations were 3.11 +/- 0.81 micrograms.ml-1, these levels decreased by one third with the initiation of CPB. By the end of CPB the concentrations had returned to levels roughly equivalent to those observed at the time of aortic cannulation. Following cessation of the infusion, ketamine concentration declined in a log-linear fashion with a half-life averaging 2.12 hr. (range 1.38-3.09 hr). CONCLUSION: This dosage regimen maintained general anaesthetic concentrations of ketamine throughout the operative period. These levels should result in brain tissue concentrations in excess of those previously shown to be neuroprotective in animals. Thus we conclude that this infusion regimen would be reasonable to be use in order to assess the potential neuroprotective effects of ketamine in humans undergoing CPB.

Cardiopulmonary bypass, temperature, and central nervous system dysfunction.

BACKGROUND: Neurological injury is an important cause of morbidity and mortality after cardiac surgery. With the advent of warm heart surgery, the neuroprotective role of hypothermic cardiopulmonary bypass (CPB) has come under increasing scrutiny. Preliminary work by us in the area found no increased risk of neurological morbidity with normothermic CPB in a small group of patients and suggested a possible benefit. The purpose of the present study is to compare the incidence of neurological and neuropsychological dysfunction in a larger number of patients randomized to warm or cold aortocoronary bypass surgery. METHODS AND RESULTS: With the approval of the institutional research ethics committee, 201 aortocoronary bypass patients were randomized to normothermic or moderate hypothermic CPB and subjected to neurological and neuropsychological evaluation. These subjects were a subset of patients enrolled in a large multicenter trial comparing warm versus cold heart surgery. The examinations took place preoperatively, 5 days after operation, and a 3-month follow-up. The examination consisted of a clinical neurological examination and a brief neuropsychological test battery. The neuropsychological tests included the Buschke selective reminding procedure, the Wechsler memory scale-revised visual reproduction subtest, the trial making test (parts A and B), the Wechsler adult intelligence scale-revised digit symbol subtest, and the grooved pegboard test. The examiner and subjects were unaware of the CPB temperature allocation (warm, > 34 degrees C; cold, < or = 28 degrees C). Statistical analysis was performed using the SAS statistical software package. Two hundred one patients were enrolled in the study. Of these, 155 patients completed the entire protocol and were included in the final analysis (warm group, n = 78; cold group, n = 77). One patient in the warm group died perioperatively from a massive hemispheric stroke. Another warm group patient was unable to complete neuropsychological evaluation because of a perioperative stroke. Thus, 153 patients completed the entire series of neuropsychological tests. A total of 6 patients (warm group, n = 2; cold group, n = 4; P = NS) suffered from perioperative focal neurological deficits. There was a consistent deterioration in scores from tests of psychomotor speed/coordination (trial making, digit symbol, pegboard) in the early postoperative period, which resolved by the 3-month follow-up. Tests of memory (Buschke, Wechsler memory scale) showed no evidence of patient deterioration in the postoperative period. No difference was seen between the warm and cold groups. CONCLUSIONS: In this randomized trial of normothermic versus hypothermic CPB, we found deterioration in scores of tests of psychomotor speed but not of memory in the early postoperative period. We were unable to demonstrate any neuroprotective effect from moderate hypothermia in this patient population.