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Biomedical subjects

D L Reich

Publications and source records attributed to D L Reich.

At least 19 recordsLinked to original sources
PubMed2004

Application of fuzzy functions for visual presentation of medical data.

While interpretation of medical data is very often an ambiguous process, computers usually display results of recommendations, provided by both human experts and computer algorithms, as concrete data. This study proposes a visual presentation of relative degrees of uncertainty along with "standard" concrete medical data. A medical parameter (mean arterial pressure) is dynamically evaluated during surgery for being too low or too high. Fuzzy membership functions are utilized to display degrees of deviation in the form of a clear and concise pie chart. Thus, in the Operating Room the anesthesiologist can be provided with an easy statistical assessment of uncertainty of existing recommendations.

Algorithms↗
PubMed2001

Retrograde cerebral perfusion as a method of neuroprotection during thoracic aortic surgery.

Retrograde cerebral perfusion is commonly used as an adjunct to hypothermic circulatory arrest to enhance cerebral protection during thoracic aortic surgery. This review summarizes a large number of studies that demonstrate a spectrum of beneficial, neutral, and detrimental effects of retrograde cerebral perfusion in humans and experimental animal models. It remains unclear whether retrograde cerebral perfusion provides effective cerebral perfusion, metabolic support, washout of embolic material, and improved neurological and neuropsychological outcome.

Animals↗
PubMed2001

Retrograde cerebral perfusion during thoracic aortic surgery and late neuropsychological dysfunction.

OBJECTIVE: Retrograde cerebral perfusion (RCP) is commonly used in thoracic aortic surgery, ostensibly to provide metabolic support, maintain cerebral hypothermia and/or wash out particulate emboli. We tested the hypothesis that RCP would affect neuropsychological outcome in a clinical cohort. METHODS: Ninety-four patients undergoing elective thoracic aortic repairs requiring deep hypothermic circulatory arrest consented to participate in this study. These patients underwent preoperative neuropsychological evaluation and comprise the reference group. Fifty-six of these patients also underwent neuropsychological evaluation several weeks postoperatively, 12 of whom (21%) had RCP. The neuropsychological domains tested were attention, processing speed, memory, executive function, and fine motor function. A global assessment of impairment, negative neuropsychological outcome (NNO), was defined as a postoperative decrease in function in two or more neuropsychological domains for patients with at least three domains tested both pre- and postoperatively (n=48). The relationship of three potential predictors (RCP, cerebral ischemia time and patient age) to negative outcomes was analyzed using Wilcoxon two-sample tests, chi(2) tests, Mantel-Haenszel tests and multiple logistic regression. P<0.05 was considered significant. RESULTS: Memory dysfunction and NNO had strong associations with RCP. This effect remained significant when controlling separately for age and cerebral ischemia time. CONCLUSIONS: The effects of RCP are difficult to distinguish from those of age and prolonged cerebral ischemia time, because complex thoracic aortic repairs are associated with advanced age, prolonged cerebral ischemia and use of RCP. Despite this limitation, these preliminary data indicated that RCP had no beneficial effect (and most likely a negative effect) upon cognitive outcome.

Adult↗
PubMed2001

Decreased endotoxin immunity is associated with greater mortality and/or prolonged hospitalization after surgery.

BACKGROUND: Patients undergoing noncardiac surgery often develop postoperative morbidity, potentially attributable to endotoxemia and the systemic inflammatory response syndrome. Endogenous antibodies to endotoxin may confer protection from endotoxin-mediated toxicity. The authors sought to determine the association of preoperative antiendotoxin immunity and death or prolonged hospitalization in a broad population of general surgical patients undergoing major surgery. METHODS: To test the hypothesis that low preoperative serum antiendotoxin core antibody (EndoCAb) concentration is an independent predictor of adverse outcome after general surgery, 1,056 patients undergoing routine noncardiac surgery were enrolled into a prospective, blinded, cohort study. Immunoglobulin M EndoCAb, immunoglobulin G EndoCAb, total inmunoglobulin M, and immunoglobulin G concentrations were measured in serum obtained preoperatively. A physiologic risk score using the established POSSUM criteria was assigned preoperatively to each patient. The primary predefined composite end point (postoperative complication) was either in-hospital death or postoperative length of stay greater than 10 days. Multivariate logistic regression was used to test the study hypothesis. RESULTS: Overall, postoperative complication occurred in 234 of the 1,056 patients (22.1%). Lower immunoglobulin M EndoCAb concentration (P = 0.006) predicted increased risk of postoperative complication independent of POSSUM physiologic risk score (P < 0.001). In contrast, total immunoglobulin M and total immunoglobulin G concentrations did not predict adverse outcome. Complications involved multiple organ systems and were generally unrelated to the type or site of surgery, consistent with the systemic inflammatory response syndrome. CONCLUSIONS: Adverse outcome after routine noncardiac surgery is common and is predicted in part by low concentrations of EndoCAb. The authors' findings suggest that endotoxemia may be a cause of postoperative morbidity after routine noncardiac surgery.

Adult↗
PubMed2000

Development of a decision support system to assist anesthesiologists in operating room.

The complexity of modern anesthesia procedures requires the development of decision-support systems functioning in a smart-alarm capacity. We developed computer algorithms to detect critical conditions during surgery (light anesthesia or unstable blood pressure), based on computerized anesthesia records containing hemodynamic data (heart rate, mean arterial pressure and systolic arterial pressure). Our analysis indicated that a > or = 12% change in mean arterial blood pressure (MAP), compared with the median value of MAP over the preceding 10-min interval, may be chosen as the criterion for detecting LA, with a sensitivity of 96% and a specificity of 91%. The best agreement between human and computer ratings of blood pressure lability (correlation coefficient 0.78) was achieved when we used the absolute value of the fractional change of the mean arterial pressure (magnitude of FCM) between one 2-min epoch and the next 2-min epoch. Work is under progress to develop a decision-support system to alert clinicians in the operating room environment to critical events.

Algorithms↗
PubMed2000

Arterial blood pressure and heart rate discrepancies between handwritten and computerized anesthesia records.

UNLABELLED: Previous publications suggest that handwritten anesthesia records are less accurate when compared with computer-generated records, but these studies were limited by small sample size, unblinded study design, and unpaired statistical comparisons. Eighty-one pairs of handwritten and computer-generated neurosurgical anesthesia records were retrospectively compared by using a matched sample design. Systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and heart rate (HR) data for each 5-min interval were transcribed from handwritten records. In computerized records, the median of up to 20 values was calculated for SAP, DAP, and HR for each consecutive 5-min epoch. The peak, trough, standard deviation, median, and absolute value of the fractional rate of change between adjacent 5-min epochs were calculated for each case. Pairwise comparisons were performed by using Wilcoxon tests. For SAP, DAP, and HR, the handwritten record peak, standard deviation, and fractional rate of change were less than, and the trough and median were larger than, those in corresponding computer records (all with P: < 0.05, except DAP median and HR peak). Considering together all the recorded measurements from all cases, extreme values were recorded more frequently in computerized records than in the handwritten records. IMPLICATIONS: The discrepancies between handwritten and computerized anesthesia records suggest that some of the data in handwritten records are inaccurate. The potential for inaccuracy should be considered when handwritten records are used as source material for research, quality assurance, and medicolegal purposes.

Adolescent↗
PubMed1999

Temporary neurological dysfunction after deep hypothermic circulatory arrest: a clinical marker of long-term functional deficit.

BACKGROUND: With increasing clinical experience, it has become clear that two distinct forms of neurological injury occur after operations on the thoracic aorta that require temporary exclusion of the cerebral circulation. Traditionally, evaluation of neurological outcome was limited to reporting the incidence of postoperative stroke related to ischemic infarcts due to particulate embolization. More recently, the symptom complex defined as "temporary neurological dysfunction" (TND) was recognized as a functional manifestation of subtle and presumably transient brain injury, but whether this early postoperative syndrome is associated with long-term deficits of cognitive and intellectual functions has not been established. METHODS: With Institution Review Board approval, 105 patients undergoing elective thoracic aortic surgery were entered into a protocol involving neuropsychological evaluation with a battery of tests preoperatively, and 1 and 6 weeks postoperatively. Patients who could not be tested adequately or had documented strokes were eliminated from final analysis. Seventy-one patients completed the neuropsychological evaluation, which consisted of eight tests consolidated into five domains: attention, cognitive speed, memory, executive function, and fine motor function. Independent observers also determined whether temporary dysfunction was present, and graded its severity based on a fixed but subjective clinical scale, ranging from simple disorientation and lethargy or confusion (grade 1-2) to prolonged extreme agitation or psychotic behavior requiring treatment with psychotropic drugs (grade 3-5). Data were normalized to baseline values, and were analyzed using analysis of variance, analysis of covariance (ANCOVA), and chi2 as necessary. RESULTS: A previous analysis had shown that patients who could not be tested or had poor scores 1 week postoperatively were more likely to perform poorly at 6 weeks (odds ratio 5.27, p < 0.01). In the current study, in order to determine the clinical relevance of TND, patients were analyzed retrospectively according to their performance in neuropsychological testing: patients with no change or a decline of less than 50% in tests of memory, motor function, and attention 1 week postoperatively (group 1, n = 49) were compared with those with a negative change exceeding 50% in the same functions at 1 week (group 2, n = 22). The overall incidence of TND was 28.1% (20/71). The incidence of TND in group 2 (14/22, 63%) was significantly higher than in group 1 (6/49, 12%; p = 0.0006). Similarly, the severity of TND (as assessed by clinical score > 2) was also significantly higher in group 2 (11/14) compared with group 1 (0/6; p = 0.006.) CONCLUSIONS: The incidence and severity of clinically apparent temporary neurological dysfunction correlates significantly with poor performance on neuropsychological tests 1 week postoperatively. Such poor performance predicts continued deficits in memory and motor function at 6 weeks. Thus, TND may not be a benign self-limited condition as previously supposed, but rather a clinical marker for insidious but significant neurological injury associated with measurable long-term deficits in cerebral function. A concerted effort to reduce the incidence of this complication is therefore necessary.

Aged↗
PubMed1999

Cerebral metabolic suppression during hypothermic circulatory arrest in humans.

BACKGROUND: Hypothermic circulatory arrest (HCA) is used in surgery for aortic and congenital cardiac diseases. Although studies of the safety of HCA in animals have been carried out, the degree to which metabolism is suppressed in patients during hypothermia has been difficult to determine because of problems with serial measurements of cerebral blood flow in the clinical setting. METHODS: To quantify the degree of metabolic suppression achieved by hypothermia, we studied 37 adults undergoing operations employing HCA. Cerebral blood flow was estimated using an ultrasonic flow probe on the left common carotid artery, and cerebral arteriovenous oxygen content differences were calculated from jugular venous bulb and arterial oxygen saturations. Cerebral metabolic rates while cooling were then ascertained. The temperature coefficient, Q10, which is the ratio of metabolic rates at temperatures 10 degrees C apart, was determined. RESULTS: The human cerebral Q10 was found to be 2.3. The cerebral metabolic rate is still 17% of baseline at 15 degrees C. If one assumes that cerebral blood flow can safely be interrupted for 5 min at 37 degrees C, and that cerebral metabolic suppression accounts for the protective effects of hypothermia, the predicted safe duration of HCA at 15 degrees C is only 29 min. CONCLUSIONS: The safe intervals calculated from measured cerebral oxygen consumption suggest that shorter intervals and lower temperatures than those currently used may be necessary to assure adequate cerebral protection during hypothermic circulatory arrest.

Adult↗
PubMed1999

Neuropsychologic outcome after deep hypothermic circulatory arrest in adults.

INTRODUCTION: Pediatric patients undergoing prolonged periods of deep hypothermic circulatory arrest have been found to experience long-term deficits in cognitive function. However, there is limited information of this type in adult patients who are undergoing deep hypothermic circulatory arrest for thoracic aortic repairs. METHODS: One hundred forty-nine patients undergoing elective cardiac or thoracic aortic operations were evaluated preoperatively; 106 patients were evaluated early in the postoperative period (EARLY), and 77 patients were evaluated late in the postoperative period (LATE) with a battery of neuropsychologic tests. Seventy-three patients had routine cardiac operations without deep hypothermic circulatory arrest, and 76 patients with deep hypothermic circulatory arrest were divided into 2 subgroups: those with 1 to 24 minutes of deep hypothermic circulatory arrest (n = 36 patients) and those with 25 minutes or more of deep hypothermic circulatory arrest (n = 40 patients). The neuropsychologic test battery consisted of 8 tests encompassing 5 domains: attention, processing speed, memory, executive function, and fine motor function. Data were normalized to baseline values, and changes from baseline were analyzed by analysis of covariance, multivariate logistic regression, and survival functions. RESULTS: In all domains, poor performance or inability to be tested EARLY were significant predictors of poor performance LATE (odds ratio, 5.27; P <.01). Deep hypothermic circulatory arrest of 25 minutes or more and advanced age were significant predictors of poor performance LATE for the memory and fine motor domains. Deep hypothermic circulatory arrest of 25 minutes or more (odds ratio, 4. 0; P =.02) was a determinant of prolonged hospital stay (>21 days). CONCLUSION: Deep hypothermic circulatory arrest of 25 minutes or more and advanced age were associated with memory and fine motor deficits and with prolonged hospital stay.

Age Factors↗
PubMed1999

Endovascular aortic repair is associated with greater hemodynamic stability compared with open aortic reconstruction.

OBJECTIVE: Examination of overall hemodynamic stability in patients undergoing endovascular aortic repair (EAR) compared with open aortic repair (OAR). DESIGN: Retrospective study. SETTING: University hospital setting. PARTICIPANTS: Seventy-two patients undergoing OAR and 17 patients undergoing EAR were studied. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Physiologic parameters were extracted every 15 seconds from computerized anesthesia records. Median values were calculated for every 2-minute epoch, and the absolute value of the fractional change in median (|FCM|) from epoch to epoch was calculated for a maximum of 5 hours during the intraoperative period. The incidence of extremes in hemodynamic parameters was compared. Data are presented as median and interquartile ranges. The frequency of |FCM| greater than 0.06 for mean arterial pressure (MAP) was significantly greater in the OAR compared with the EAR group (0.37 [0.30, 0.46] vs 0.14 [0.11, 0.21], p < 0.0001), implying greater stability in MAP during EAR. Similarly, the mean pulmonary artery pressures (MPAPs) were significantly more stable during EAR compared with OAR (frequency of |FCM| > 0.07: EAR, 0.20 [0.16, 0.27] vs OAR, 0.32 [0.26, 0.391; p < 0.01). No intergroup differences were detected in heart rate (HR), systolic (SPAP) or diastolic pulmonary artery pressures (DPAP), or central venous pressures (CVPs). With the exception of a greater incidence of low CVP during EAR, there were no significant differences in the frequency of extremes of hemodynamic values between groups. CONCLUSION: These results show improved hemodynamic stability during EAR compared with OAR.

Aged↗
PubMed1999

Object-oriented analysis and design of a health care management information system.

We have created a prototype for a universal object-oriented model of a health care system compatible with the object-oriented approach used in version 3.0 of the HL7 standard for communication messages. A set of three models has been developed: (1) the Object Model describes the hierarchical structure of objects in a system--their identity, relationships, attributes, and operations; (2) the Dynamic Model represents the sequence of operations in time as a collection of state diagrams for object classes in the system; and (3) functional Diagram represents the transformation of data within a system by means of data flow diagrams. Within these models, we have defined major object classes of health care participants and their subclasses, associations, attributes and operators, states, and behavioral scenarios. We have also defined the major processes and subprocesses. The top-down design approach allows use, reuse, and cloning of standard components.

Acute Disease↗
PubMed1999

The relationship of cognitive, personality, and academic measures to anesthesiology resident clinical performance.

UNLABELLED: Cognitive skills (including vigilance), personality factors, and standardized academic test performance may be associated with clinical competence in anesthesiology to varying degrees. Sixty-seven anesthesiology residents in training at one center between 1993 and 1995 were administered the modified Vigil (For Thought, Ltd., Nashua, NH), the Paced Auditory Serial Addition Test, the California Personality Inventory, the State-Trait Anxiety Inventory, and five standardized academic performance tests. The clinical performance of anesthesiology residents was rated on a quarterly basis by a clinical competence committee. A growth curve model indicated that there was significant variability in clinical competence at the start of residency and a statistically significant improvement over time, and that the relative ranking of the residents remained stable over the course of training. Of 46 potential variables, 7 were associated (P < 0.10) with poor clinical performance; these were subjected to a multivariate test (Mantel-Haenszel). Cognitive variables predicting poor clinical performance were difficulty performing a rapid mental arithmetic test requiring divided attention and commission errors during complex visual target detection. Personality variables predicting poor clinical performance were introversion and flexibility. A predictive academic variable was poor anesthesia knowledge as measured by using two different tests during the first month of training. There were varying levels of independence among these variables. IMPLICATIONS: Early academic test performance and certain cognitive and personality tests were associated with the clinical performance of anesthesiology residents. The predictive value of these findings should be confirmed in a prospective, multicenter study.

Anesthesiology↗
PubMed1999

Intraoperative hemodynamic predictors of mortality, stroke, and myocardial infarction after coronary artery bypass surgery.

UNLABELLED: Evidence that intraoperative hemodynamic abnormalities influence outcome is limited. The purpose of this study was to determine whether intraoperative hemodynamic abnormalities were associated with mortality, stroke, or perioperative myocardial infarction (PMI) in a large cohort of patients undergoing coronary artery bypass grafting. Risk factors and outcomes were queried from a state-mandated cardiac surgery reporting system at two hospitals in New York, NY. Intraoperative hemodynamic abnormalities were derived from computerized anesthesia records by assessing the duration of exposure to moderate or severe extremes of hemodynamic variables. Multivariate logistic regression identified independent predictors of perioperative mortality, stroke, and PMI. Among 2149 patients, there were 50 mortalities, 51 strokes, and 85 PMIs. In the precardiopulmonary bypass (pre-CPB) period, pulmonary hypertension was a predictor of mortality (odds ratio [OR] 2.1, P = 0.029), and bradycardia and tachycardia were predictors of PMI (OR 2.9, P = 0.007 and OR 2.0, P = 0.028, respectively). During CPB, hypotension was a predictor of mortality (OR 1.3, P = 0.025). Post-CPB, tachycardia was a predictor of mortality (OR 3.1, P = 0.001), diastolic arterial hypertension was a predictor of stroke (OR 5.4, P = 0.012), and pulmonary hypertension was a predictor of PMI (OR 7.0, P < 0.001). Increased pulmonary arterial diastolic pressure post-CPB was a predictor of mortality (OR 1.2, P = 0.004), stroke (OR 3.9, P = 0.002), and PMI (OR 2.2, P = 0.001). Rapid intraoperative variations in blood pressure and heart rate were not independent predictors of these outcomes. These findings demonstrate the prognostic significance of intraoperative hemodynamic abnormalities, including data from pulmonary artery catheterization, to adverse postoperative outcomes. It is not known whether interventions to control these variables would improve outcome. IMPLICATIONS: Intraoperative hemodynamic abnormalities, including pulmonary hypertension, hypotension during cardiopulmonary bypass, and postcardiopulmonary bypass pulmonary diastolic hypertension, were independently associated with mortality, stroke, and perioperative myocardial infarction over and above the effects of other preoperative risk factors.

Blood Pressure↗
PubMed1999

Beneficial effects from beta-adrenergic blockade in elderly patients undergoing noncardiac surgery.

BACKGROUND: Perioperative beta-blockade has been shown to improve long-term cardiac outcome in noncardiac surgical patients. A possible mechanism for the reduced risk of perioperative myocardial infarction is the attenuation of the excitotoxic effects of catecholamine surges by beta-blockade. It was hypothesized that beta-blocker-induced alteration of the stress response was responsible for the reported improvements in cardiovascular outcome. Several variables associated with the perioperative use of beta-blockade were also evaluated. METHODS: Sixty-three patients were randomly assigned to one of three groups: group I, no atenolol; group II, pre- and postoperative atenolol; group III, intraoperative atenolol. Hormonal markers of the stress response (neuropeptide Y, epinephrine, norepinephrine, cortisol, and adrenocorticotropic hormone) were evaluated preoperatively and for 72 h after surgery. RESULTS: Perioperative beta-blockade did not significantly alter the hormonal stress response. However, the beta-blocked patients showed improved hemodynamic stability during emergence and postoperatively. They also received less fentanyl intraoperatively (27.7%, P < 0.0001), experienced faster early recovery, had lower pain scores, and required less analgesia in the postanesthesia care unit. Cardiac troponin I release was detected in 8 of 19, 4 of 20, and 5 of 20 patients in groups I, II, and III, respectively (not significant). Three patients in group I had cardiac troponin I levels consistent with myocardial infarction. CONCLUSION: Beta-blockade does not reduce the neuroendocrine stress response, suggesting that this mechanism is not responsible for the previously reported improved cardiovascular outcome. However, it confers several advantages, including decreased analgesic requirements, faster recovery from anesthesia, and improved hemodynamic stability. The release of cardiac troponin I suggests the occurrence of perioperative myocardial damage in this elderly population, which appears to be independent of the neuroendocrine stress response.

Adrenergic beta-Antagonists↗
PubMed1999

Descending thoracic and thoracoabdominal aneurysm.

The low incidence of permanent spinal cord injury in our most recent cohort (Group II) of patients suggests that serial sacrifice of intersegmental vessels, careful monitoring of spinal cord function are effective in preventing paraplegia after descending thoracic and thoracoabdominal aneurysm operations. Updated anesthetic and postoperative care minimized overall mortality risk. (Ref. 9.)

Aortic Aneurysm, Abdominal↗
PubMed1998

Heparin and protamine titration do not improve haemostasis in cardiac surgical patients.

PURPOSE: Weight-based heparin and protamine dosing strategies for cardiopulmonary bypass (CPB) do not take into account interpatient variability in drug sensitivity and may result in bleeding complications. We compared the Hemochron RxDx heparin and protamine titration system with standard weight based management with regard to heparin dose, protamine dose, and perioperative bleeding. METHODS: One hundred and thirty-five cardiac surgical patients were randomised into four groups. Group 1 received standard heparin and protamine management: Group 2 received heparin and protamine by in vitro titration. Group 3 had the heparin dose titrated, and group 4 had the protamine dose titrated. Coagulation tests, bleeding, and transfusion requirements were measured. RESULTS: The initial heparin bolus predicted by the titration was < 300 U.kg-1 in all patients. Group 2 received a lower heparin bolus for the initiation of bypass but total heparin doses were not different among groups (group 1 = 365 +/- 43, group 2 = 348 +/- 73 U.kg-1, group 3 = 394 +/- 86 U.kg-1, group 4 = 376 +/- 60; P = 0.06). Groups 2 and 4 received a lower initial and a lower total protamine dose (total dose group 1 = 4.03 +/- 0.65 mg.kg-1, group 2 = 3.56 +/- 1.11 mg.kg-1, group 3 = 4.22 +/- 0.90 mg.kg-1, group 4 = 3.38 +/- 0.98 mg.kg-1, P = 0.001). The incidences of incomplete heparin neutralisation (P = 0.14) and heparin rebound (P = 0.1) were not different among groups. Postoperative bleeding and transfusion requirements did not differ. CONCLUSION: In cardiac surgical patients, heparin and protamine titration did predict a lower protamine dose but did not result in a measurable improvement in haemostasis during the perioperative period.

Analysis of Variance↗