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Biomedical subjects

K R Hess

Publications and source records attributed to K R Hess.

At least 91 records · Page 5Linked to original sources
PubMed1992

A model of the phonatory response time of stutterers and fluent speakers to frequency-modulated tones.

Stutterers and fluent speakers tracked frequency-modulated tones by humming. The response time (RT) to the first corrective change in fundamental frequency in response to linear ramps of increasing and decreasing frequency was measured. The results demonstrate that RT is a function of the stimulus ramp velocity. A model of this dependency is provided which consists of parameters of threshold frequency and a fixed time delay. The estimated threshold frequency for the fluent speakers is 2.029 Hz with 95% confidence interval: (1.70 Hz, 2.35 Hz) whereas that of the stutterers is 3.937 Hz (3.28 Hz, 4.60 Hz). These threshold frequencies are significantly different (p < 0.0001). This implies that stutterers are slower to respond to changes in frequency than are fluent speakers. The fixed time delays for the two groups are not significantly different. This means that it is possible for the stutterers to respond as fast as the fluent speakers (i.e., their basic "reflexes" are the same); however, they spend more time in the detection of the change in a tracking signal. This supports the model of the stuttered event as being triggered by an instability in a multiloop speech motor control system.

Adult↗
PubMed1992

Thoracoabdominal aortic aneurysms associated with celiac, superior mesenteric, and renal artery occlusive disease: methods and analysis of results in 271 patients.

Two hundred seventy-one of 1509 patients who underwent thoracoabdominal aortic repairs had either celiac or superior mesenteric or renal artery occlusive disease. These latter patients were treated by endarterectomy or bypass between June 20, 1960 and Jan. 10, 1991. After 1987, the 30-day survival rate was 93% (79 of 85) compared with 90% (245 of 271) before 1988. Multivariate predictors of death were age, postoperative reoperation for bleeding, and cardiac complications (p less than 0.05). Renal complications (13% dialysis, 35 of 271) were associated with preoperative renal dysfunction, elevated preoperative serum creatinine level, urine clearance time of dye, extent of the aorta replaced, coagulopathy, and paraplegia or paraparesis (p less than 0.05). The incidence of postoperative renal dysfunction was reduced by renal artery endarterectomy (p less than 0.05). On univariate analysis the risk of renal failure was reduced by renal artery perfusion with cold Ringer's lactate solution (p less than 0.05). Gastrointestinal complications (9%, 25 of 271) were associated with a history of peptic ulcer disease on multivariate analysis (p less than 0.05). The Kaplan-Meier 5-year survival rates for patients with and without occlusive disease were 53% and 60%, respectively, and at 10 years 37% and 30%, respectively (p = 0.08). We conclude that endarterectomy or bypass of occlusive visceral disease reduces the risk of renal failure after thoracoabdominal aortic aneurysm repairs, does not decrease early or late survival, and does not increase the risk of gastrointestinal complications.

Aged↗
PubMed1991

Percutaneous transluminal coronary angioplasty utilizing prolonged balloon inflations: initial results and six-month follow-up.

Coronary angioplasty (PTCA) using prolonged balloon inflation has obviated emergency coronary bypass surgery in some patients with acute occlusions at the time of PTCA. However, the use of prolonged balloon inflations has not been shown to improve long-term restenosis rates. As an alternative to the passive autoperfusion catheter, we evaluated a hemoperfusion system in which blood was obtained from the side arm of an arterial sheath and infused through the central lumen of standard balloon catheters via a modified Medrad IV pump during balloon inflation. PTCA was performed in 71 male patients (median age 57 yr). The median balloon inflation time was 4.8 minutes and the median rate of blood perfusion was 30 ml/min. PTCA was successful (lumen increase by 20 percentage points) in 83% of patients (59/71) with diameter stenosis decreasing from a median 82% to 30%. Emergency coronary bypass was required in four patients (5%). Angiographic data for six-month followup was available on 37 patients. The restenosis rate (loss of 50% of gain) was 46% (17/37). The conclusion is that prolonged balloon inflation angioplasty has a role in complicated PTCA but offers no advantage in improving long-term restenosis rates in elective PTCA.

Adult↗
PubMed1991

Post-caesarean section analgesia: a comparison of epidural butorphanol and morphine.

Epidural butorphanol 1, 2 and 4 mg were compared with morphine, 5 mg, for postoperative analgesia in 92 consenting, healthy, term parturients who had undergone Caesarean section under epidural lidocaine anaesthesia in a randomized double-blind study. Postoperative pain was assessed using a visual analogue scale and recorded with heart rate, blood pressure and respiratory rate. The demographic characteristics, and the incidences of primary and repeat Caesarean sections, were not different among the four treatment groups. At 15, 30, 45 and 60 min after treatment the median pain scores following butorphanol were similar and lower than those following morphine (P less than 0.05). Calculated median percentage pain relief values for butorphanol were higher than morphine at each of these times (P less than 0.05). At 90 min and 2 hr the pain scores and pain relief values were similar. Beyond 45 min the number of patients requesting supplemental medication and dropping out of the study increased progressively in both the butorphanol and morphine treated patients. The attrition profiles for butorphanol were different from morphine (P less than 0.01). The median time in the study was greater than 24 hr for morphine, and 3, 2.5 and 4 hr for butorphanol, 1, 2 or 4 mg, respectively. No patient developed a clinically important change in heart rate or blood pressure, and none experienced a decrease in respiratory rate below 12 breaths.min-1. One of 69 patients (1.4 per cent) who received butorphanol developed pruritus compared with ten (43 per cent) of 23 patients who received morphine. The global assessments of the adequacy of analgesia were indistinguishable between morphine and butorphanol. Epidural butorphanol provides safe, effective postoperative analgesia, has a prompt onset, and a limited duration.

Adult↗
PubMed1991

Ruptured aneurysm of the descending thoracic and thoracoabdominal aorta. Analysis according to size and treatment.

Acute rupture was confirmed at operation in 117 patients treated for descending thoracic or thoracoabdominal aortic aneurysm. Descending thoracic (n = 80) aortic rupture occurred into lung or esophagus in 8, the pleural cavity in 49, and the mediastinum in 23. Upper abdominal aortic (n = 37) rupture occurred into peritoneal cavity in 3 and into retroperitoneal tissues in 34. Aneurysmal size (range, 5 to 17 cm; median, 8 cm) could be determined retrospectively in 86 patients; 59 (74%) descending thoracic and 27 (73%) abdominal aorta. Size (external diameter) in the former was 8 (14%), 5 to 6 cm; 21 (36%), 6 to 8 cm; 23 (39%), 8 to 10 cm; and 7 (12%) greater than 10 cm. Size at the abdominal site was similar. Thus size was not greater than 10 cm in 52 (88%) (range, 5 to 10 cm), which contradicts opinions that thoracic aneurysms rupture only when size exceeds 10 cm. Twenty-nine patients (25%) were hypotensive (systolic blood pressure less than 100 mmHg), of whom 16 (55%) had cardiac arrest before operation. Associated conditions included advanced age (greater than or equal to 75 years) in 26 (22%), coronary artery disease in 41 (35%), chronic obstructive pulmonary disease in 46 (39%), renal insufficiency in 25 (21%), and cardiovascular disease in 22 (18%). The overall early survival rate (30-day) was 89 of 117 patients (76%); 69% in patients with hypotension, 56% of patients with cardiac arrest, 88% in good-risk patients. Five-year (Kaplan-Meier) survival was 28%. Because elective operation is associated with 92% survival, this should be considered before rupture when aneurysm is 5 cm or larger in good-risk patients, in patients with symptomatic aneurysms, and in most patients with larger aneurysms.

Adolescent↗
PubMed1991

A prospective study of respiratory failure after high-risk surgery on the thoracoabdominal aorta.

From June 1960 to September 1990, 1414 patients underwent repair of thoracoabdominal aortic aneurysms, of whom 112 (8%) had pulmonary complications requiring respiratory support with tracheostomy; subsequently 45 (40%) died in the hospital. We determined by stepwise logistic regression analysis, in a prospective study of high-risk type I and II thoracoabdominal aortic aneurysms repairs, the independent predictors of respiratory failure, defined as respiratory ventilation exceeding 48 hours after operation. In 98 patients studied, 38 (39%) were women, 60 (61%) were men, 54 (55%) had type II thoracoabdominal aortic aneurysms, 34 (35%) had aortic dissection, 19 (19%) were nonsmokers, 40 (41%) exsmokers, and 39 (40%) active smokers. Before operation, 55 (56%) had chronic pulmonary disease with respiratory failure developing in 58% (p = 0.0005 versus no chronic pulmonary disease, 10/43, 23%), and of the 26 patients in the lower quarter of forced expiratory volume (1 sec) (FEV1 less than or equal to 1.45 L) respiratory failure developed in 61% (p = 0.035). In-hospital survival was 98% and 83% (p = 0.008), respectively, and cumulative survival at 6 months by Kaplan-Meier analysis was 96% and 80% (p = 0.004, log-rank test), respectively, for patients without respiratory failure (N = 56/98, 57%) and with respiratory failure (N = 42/98, 43%). On univariate analysis, the following were associated with respiratory failure (p less than 0.05): FEV1, FEV1% predicted, FVC, FEF25, FEF25% predicted, FEF25-75, FEF25-75% predicted, PaCO2 Pao2, symptoms, smoking history, chronic pulmonary disease, cryoprecipitate volume, postoperative neuromuscular deficit, cardiac complications, reoperation for bleeding, renal complication, stress ulceration, postoperative creatinine level, postoperative dialysis, and postoperative encephalopathy. The independent predictors of respiratory failure were (p less than 0.05): chronic pulmonary disease, smoking history, cardiac and renal complications. In patients with chronic pulmonary disease, the only independent predictor was FEF25 (p = 0.030). These observations may be of value in selecting patients for elective operation.

Adult↗
PubMed1991

A prospective randomized study of cerebrospinal fluid drainage to prevent paraplegia after high-risk surgery on the thoracoabdominal aorta.

This article is concerned with the study of the effect of several variables, principally that of cerebrospinal fluid drainage, on the incidence of neurologic deficit in a prospective randomized series of patients with extensive aneurysms of the descending thoracic and abdominal aorta (thoracoabdominal type I and II). Forty-six patients had cerebrospinal fluid drainage, and 52 were controls, with a total of 98 available for study. Cerebrospinal fluid pressure was continuously monitored in the former group and pressure maintained less than or equal to 10 mm Hg in 20, less than or equal to 15 mm Hg in 20, and greater than 15 mm Hg in 6 patients during period of aortic clamping. The method of treatment including reattachment of intercostal and lumbar arteries (p = 0.2), temporary atriofemoral bypass during aortic occlusion (p = 0.3), and spinal fluid drainage (p = 0.8) were not statistically significant in reducing the incidence of neurologic deficits. Thus cerebrospinal fluid drainage as we used it, was not beneficial in preventing paraplegia. On appropriate statistical analysis we found that the only significant predictor of delayed deficits was postoperative hypotension (p = 0.006).

Aortic Dissection↗
PubMed1990

Percutaneous transluminal coronary angioplasty in octogenarians.

OBJECTIVE: To assess the safety and short- and long-term outcomes of percutaneous transluminal coronary angioplasty in octogenarians. DESIGN: Retrospective chart review of clinical series. SETTING: Referral-based university medical center. PATIENTS: Consecutive series of 54 octogenarian patients (mean age, 82.4 years) who had percutaneous transluminal coronary angioplasty between March 1980 and December 1988. Of these patients, 91% presented with severe angina (Canadian Cardiovascular Society Class III or IV); 59% had unstable angina. Twenty-six patients (48%) had had a previous myocardial infarction and 15 (28%) had had previous coronary artery bypass surgery. Multivessel disease was present in 44 patients (81%). Follow-up ranged from 1 to 50 months (mean, 19 months). INTERVENTION: Percutaneous transluminal coronary angioplasty. MEASUREMENTS AND MAIN RESULTS: The angiographic success rate was 50 of 54 (93%; 95% CI, 81% to 98%) and the clinical success rate was 49 of 54 (91%; CI, 79% to 97%). Two patients had procedure-related myocardial infarction. Two patients died in the hospital, 1 from cardiac tamponade because of pacemaker perforation and 1 from cardiogenic shock after a myocardial infarction despite successful angioplasty. During the follow-up period 4 patients required bypass surgery, 2 had myocardial infarction, and 7 died (4 deaths were cardiac). Eleven patients (20%) had re-stenosis, 7 of whom were managed with repeat angioplasty, including 1 patient who had four procedures. At follow-up, 42 of 45 survivors (93%) were asymptomatic or had class II angina. The Kaplan-Meier survival for all patients, including those who died in the hospital, was 87% at 1 year and 80% at 3 years. Cumulative freedom from major cardiac events (death, myocardial infarction, or coronary bypass surgery) was 81% at 1 year and 78% at 3 years. CONCLUSIONS: Percutaneous transluminal coronary angioplasty can be done in octogenarians with a high rate of angiographic and clinical success, low complication rate, and a favorable long-term (3-year) outcome. As such, it is a treatment option in managing advanced coronary artery disease in this fragile group of patients.

Age Factors↗
PubMed1990

Diffuse aneurysmal disease (chronic aortic dissection, Marfan, and mega aorta syndromes) and multiple aneurysm. Treatment by subtotal and total aortic replacement emphasizing the elephant trunk operation.

The life expectancy of patients with aortic aneurysm is significantly prolonged by graft replacement therapy. Regardless, a significant predictor of late death is complications of either residual aortic aneurysmal disease or the development of additional aortic aneurysm. This paper reviews a personal experience in the treatment of 4170 patients with aneurysmal disease of either dissection or medial degenerative origin, indicating that multiple segment involvement was or became present in 1262 (30%) patients, 463 (67%) of 694 patients with dissection, and 799 (23%) of 3476 patients without dissection. Regardless of etiology, multiple involvement varied with the location of the presenting involved segment, i.e., ascending aorta (38%), ascending and arch (70%), descending thoracic aorta (73%), and abdominal aorta (26%). This study was limited in detail to 811 patients who had ascending and ascending and aortic arch replacement for aneurysm. These patients were divided into 3 subgroups: (1) 524 patients with no distal disease; (2) 135 patients with distal disease treated by subtotal replacement in 82 and total replacement in 53; and (3) 152 patients with distal disease not treated. The 5-year survival rate from the time of first operation, including early death from operation was 75% in group 1, 65% in group 2, and 39% in group 3. The causes of death in group 3 patients were aneurysmal rupture and/or associated disease. It is concluded that initial total aortic study and regular postoperative monitoring with computed tomographic scanning is indicated to detect extensive disease or recurrence of disease and that aggressive replacement is indicated except in patients with associated disease that does not permit operation.

Adolescent↗
PubMed1990

Dissection of the aorta and dissecting aortic aneurysms. Improving early and long-term surgical results.

We report the improving surgical results in a consecutive series of 690 patients referred to one of us (E.S.C.) for aortic dissection between December 1956 and September 1989, a substantial portion of whom had dissection as a complication of either previous aortic (n = 113, 16) or previous cardiac (n = 54, 8%) operation. Our initial operation of choice in patients requiring multiple operations in this group of 690 patients was based on the most life-threatening or symptomatic aortic segment involved, which was ascending aorta and/or aortic arch (Asc/Arch) in 301 (44%) patients, descending thoracic aorta (Desc) in 195 (28%) patients, and thoracoabdominal aorta (TaA) in 194 (28%) patients. As detailed below, considerable improvement occurred in the 30-day survival rates over time, particularly for acute dissection: [table; see text] The independent determinants of both early and long-term mortality were identified. Independent determinants of late fatal rupture, reoperation, and neuromuscular dysfunction for distal dissectors were also identified. In our experience, continued aggressive surgical intervention for aortic dissection with modern operative techniques has resulted in markedly improved 30-day operative survival (approaching 95% including those patients with acute dissection) and significant improvement in late results.

Acute Disease↗
PubMed1989

Prediction of left ventricular ejection fraction using a unique method of chest x-ray and ECG analysis: a noninvasive index of cardiac performance based on the concept of heart volume and mass interrelationship.

A reasonably accurate, simple, inexpensive, noninvasive method of determining ejection fraction (EF) is necessary to evaluate left ventricular function in epidemiologic studies and individual patients. Using the concepts of left ventricular mass reflected by precordial R wave summation (M) and left ventricular volume (V) estimated by chest roentgenography in 114 patients with myocardial disease undergoing left ventriculography, EF was predicted with the formula: EF = 63.74 - (2.16.V) + (0.34.M); R2 = 0.69; standard error of the estimate (SEE) = 11. Because angiographic inferior wall motion (IWM) abnormalities significantly affected the results, but inferior Q waves were usually only present in patients having one infarct, a noninvasive technique to predict the presence of inferior wall motion abnormality (IMA) in patients having multiple infarcts was developed and based on the relationship of precordial R wave summation (M) and roentgenographic heart volumenometry (V). By combining V, M, and IMA (which predicted IWM) to determine EF, multiple linear regression analysis showed that EF = 67.30 - (1.56.V) + (0.23.M) - (14.18 IMA) (R2 = 0.77; SEE = 9). Prospective validation of the formula was then done in 139 consecutive individuals, with R2 = 0.49 and SEE = 9. This study demonstrates that routinely performed, simple, inexpensive clinical tests provide data that can be combined by multiple regression analysis to predict resting EF in patients with heart disease affecting the left ventricle. This unique method may allow inexpensive ventricular function screening in large population studies and in addition might provide an independent index of myocardial performance for clinical use, since it reflects the amount of contractile mass per unit of left ventricular volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Hypothermic-induced electrocerebral silence, prolonged circulatory arrest, and cerebral protection during cardiovascular surgery.

Certain cardiovascular operations require cardiopulmonary bypass and prolonged circulatory arrest to provide an adequate operative field. Profound hypothermia is induced to protect brain function during these periods without cerebral perfusion. Because peripheral body temperatures may not be valid indicators of brain temperature, we conducted this study to establish an alternative, more reliable, method of determining the appropriate level of hypothermia. We measured peripheral body temperatures from 3 sites (rectum, nasopharynx, and esophagus) at the onset of hypothermic-induced electrocerebral silence (ECS) in the intraoperative electroencephalogram (EEG) of 56 adults undergoing cardiovascular procedures. The EEG in most patients showed a characteristic progression of changes from its normal resting state during cooling. Gradual depression and slowing of background rhythms was followed by generalized, periodic, slow-wave transients, prolongation of the intervals between the transients, and then the onset of ECS. In cases in which the slow-wave transients did not appear, the initial depression and slowing of background activity gradually progressed to ECS. No consistent relationship was found between peripheral body temperatures at various sites and the onset of ECS. Using EEG-guided hypothermia, there was low morbidity and mortality. These data suggest that ECS is a safe and reliable guide for determining the appropriate level of hypothermia during cardiovascular procedures.

Adult↗
PubMed1989

Impact of cardiovascular operation on survival in the Marfan patient.

This report is concerned with the surgical treatment of cardiovascular manifestations of Marfan syndrome in 151 patients by 280 operations, 70 before referral, 203 by the authors during a 16-year period, and seven by others in the follow-up interval. This therapy resulted in mitral valve replacement in 13, aortic valve replacement in 135, aortic segment replacement in 151 (including total aortic replacement in 10), nearly total aortic replacement in 26, entire thoracic aortic replacement in seven, and replacement of the entire descending and abdominal aorta in 20 patients. The early (30-day) survival was 94%, and the 5- and 10-year Kaplan-Meier survival was 75% and 56%, respectively. Fusiform aneurysms were present in the ascending aorta, aortic arch, or both in 135, the descending aorta in two, the thoracoabdominal aorta in four, and the abdominal aorta in seven. Aortic dissection occurred in 102 (67%) patients, and 34 (22%) patients with ascending aortic operations required reoperation. This study suggests that the results of current techniques warrant a more aggressive approach to these problems to permit better long-term results.

Adolescent↗
PubMed1989

Appraisal of adjuncts to prevent acute renal failure after surgery on the thoracic or thoracoabdominal aorta.

We evaluated 1525 consecutive patients who had undergone thoracic or thoracoabdominal aortic surgery to ascertain the factors associated with the development of acute renal failure. Complete data were available in 1233 patients who were treated recently, and these were analyzed. Acute renal failure, severe enough to require dialysis, developed in 5.5% of this group (68/1233): 2.3% and 7%, respectively, for descending (9/391) and thoracoabdominal repairs (59/842). Of interest, on multivariate analysis, both renal artery endarterectomy for occlusive disease (p = 0.0006) and chronic dissection (p = 0.03) were associated with significantly less acute renal failure. On multivariate analysis, the significant independent predictors (p less than 0.05) of acute renal failure were preexistent renal dysfunction, evidence of diffuse atherosclerosis, the use of the pump bypass, and markers of hemodynamic instability. Contrary to earlier reports based on a smaller number of patients, we found that neither the use of pump bypass (7% acute renal failure), atriorenal bypass (8% acute renal failure), nor cold Ringer's lactate (3% acute renal failure) appeared to significantly avert the complication of acute renal failure. Indeed, pump bypass appeared to be deleterious (p = 0.0146) and perfusion with cold Ringer's lactate was not without risk. Furthermore, in a prospective evaluation of angiotensin converting enzyme blockers, we were unable to show that they afforded renal protection after transient renal ischemia. This study has clarified the clinical problems associated with acute renal failure and lays the foundation for future research.

Acute Kidney Injury↗
PubMed1989

Surgical treatment of aneurysm and/or dissection of the ascending aorta, transverse aortic arch, and ascending aorta and transverse aortic arch. Factors influencing survival in 717 patients.

Ascending aorta and/or aortic arch reconstruction by composite valve graft (281, 39%), separate valve graft (117, 16%), graft only (256, 36%), and other procedures (63, 9%) was used for aneurysm or dissection caused by trauma (6), infection (20), aortitis (46), dissection (261: acute 72, chronic 189), and medial degeneration (384) in 717 patients during the 9-year period between Jan. 11, 1980, and Jan. 16, 1989. Of these, 150 had 173 previous heart or aortic operations and needed reoperation for progression or recurrence of aneurysm, rupture, valvular insufficiency, aortocutaneous or aorta-heart chamber fistulas, great vein or airway obstruction, and infection. Concurrent distal aneurysmal disease was present or developed in 267 (37%) patients, being most prevalent in patients with arch involvement (211/395, 53%). These patients were treated either simultaneously or later. The ages ranged from 10 to 88 years, median 61. Aneurysm symptoms were mild or absent in 593 (83%) and severe in 124 (17%). The 30-day survival rate was 91%. The independent determinants predictive of 30-day death were increasing age, severe aneurysm symptoms, diabetes, previous proximal aortic operation, need for cardiac support, postoperative tracheostomy, postoperative heart dysfunction, and stroke. Of the 319 patients who had none of the four preoperative factors, 308 (97%) survived. Survival decreased to 74% in those with two or more factors. After a total of 1193 operations, the entire aorta was replaced in 53, near total in 35, total thoracic replacement in 78, and total aorta except arch in 27. Late survival rates (Kaplan-Meier) were 66% and 57% at 5 and 7 years. Independent predictors of death were severe aneurysm symptoms, preoperative angina, extent of proximal replacement, associated residual distal aneurysm, balloon pump, renal dysfunction, cardiac dysfunction, and stroke. Five-year survival rates varied with the incidence of the four preoperative variables and age in a single patient: 78% in 413 patients with up to one variables, 57% in 193 patients with two or three, and 39% in 111 patients with three or four (p less than 0.0001).

Aortic Dissection↗
PubMed1988

Determination of brain temperatures for safe circulatory arrest during cardiovascular operation.

Profound hypothermia protects cerebral function during circulatory arrest in the surgical treatment of a variety of cardiac and aortic abnormalities. Despite its importance, techniques to determine the appropriate level of hypothermia vary; studies of temperatures recorded from multiple peripheral body sites show inconsistent findings. The purpose of this study is to establish objective criteria to consistently identify intraoperatively the safe level of hypothermia. Our studies are based on experimental evidence showing a correlation between brain temperature and development of electrocerebral silence (ECS) on the electroencephalogram (EEG), and the recognition that the EEG, as an objective measure of brain function, can easily be recorded intraoperatively. We studied 56 patients who required circulatory arrest during operation for replacement of the ascending aorta or aortic arch (N = 55) or aortic valve replacement (N = 1). Peripheral body temperatures from the nasopharynx, esophagus, and rectum and the EEG were continuously recorded during body cooling. Circulatory arrest time ranged from 14 to 109 minutes. No peripheral body temperature from a single site or from a combination of sites consistently predicted ECS. There was a wide variation in temperature among body sites when ECS occurred: nasopharyngeal, 10.1 degrees to 24.1 degrees C; esophageal, 7.2 degrees to 23.1 degrees C; rectal, 12.8 degrees to 28.6 degrees C. Fifty-one (91%) of the 56 patients survived. Three had neurological deficits, none clearly related to hypothermia. Two patients (3.6%) required reexploration for postoperative bleeding. We conclude that monitoring the EEG to identify ECS is a safe, consistent, and objective method of determining the appropriate level of hypothermia.

Aorta↗