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Biomedical subjects

B D Spiess

Publications and source records attributed to B D Spiess.

At least 55 records · Page 3Linked to original sources
PubMed1994

Cardiac anesthesia risk management. Hemorrhage, coagulation, and transfusion: a risk-benefit analysis.

Transfusion risks include the possibility of ABO/Rh incompatibility, sepsis, febrile reactions, immunosuppression, and viral transmission; incidences and consequences of these complications are reviewed. Predonation of autologous blood generally reduces the need for homologous blood by about 30% to 40%, but relatively few coronary artery bypass surgery (CABG) patients predonate blood. Drug products to decrease blood use include 1-deamino-8-D-arginine vasopressin (DDAVP), tranexamic acid, epsilon-aminocaproic acid, and aprotinin. A recent study suggests that a subgroup of patients with abnormal platelet function may benefit from a platelet therapy such as DDAVP. The prophylactic use of tranexamic acid reduces cardiac surgery postoperative blood loss, as measured by chest-tube output, by about 30%; unfortunately, data demonstrating a reduction in transfusion requirements are not available. Aprotinin use is associated with major reductions in blood transfusion requirements. Aprotinin provides platelet protection during cardiopulmonary bypass. Duration of stay in the intensive care unit was not increased by use of aprotinin, thus alleviating some concerns that aprotinin might promote coronary thrombosis. A recent report cites early graft closure as a major concern with aprotinin therapy, but data from other studies show no significant differences in rates of graft closure between patients receiving and those not receiving aprotinin. Routine use of a thromboelastogram with all cardiopulmonary bypass surgery at the University of Washington Hospital has reduced use of blood products by 30%.

Blood Coagulation Disorders↗
PubMed1994

Pulmonary artery and noninvasive hemodynamics during lung lavage in primary alveolar proteinosis.

Noninvasive hemodynamic monitoring by bioimpedance has been compared to cardiac output measured by thermodilution. The technology of bioimpedance does allow for monitoring of static thoracic impedance, a measurement thought to be affected by extravascular lung water. No contemporary studies (in the last 20 years) have examined the effectiveness of that parameter in measuring changes in lung water. This case report notes hemodynamics and examines thoracic impedance in a patient undergoing unilateral lung lavage. The hemodynamic data measured by bioimpedance and thermodilution correlated well (r = 0.97 for cardiac output). The changes in static impedance were compared to thoracic compliance during infusion of saline solution and evacuation. The changes in both parameters followed each other closely. Further work is required in patients with pulmonary edema or effusions before bioimpedance can be used to monitor such clinical events.

Adult↗
PubMed1993

Bioimpedance hemodynamics compared to pulmonary artery catheter monitoring during orthotopic liver transplantation.

Simultaneous cardiac output measurements were obtained using bioimpedance (BI) and thermodilution (TD) methods in 10 patients undergoing orthotopic liver transplantation (OLT). BI and TD data were collected during five intraoperative phases of OLT. Linear regression revealed significant correlation between BI and TD (r = 0.8, P = 0.001) with a slope of regression of 0.64. Bias analysis demonstrated a negative of BI (-0.26) when compared with TD.Sv-O2 correlated poorly with cardiac index determined by TD (r = 0.41) or BI (r = .47). BI is an accurate reproducible method for measuring cardiac output and may be a useful adjunct to the pulmonary artery catheter for hemodynamic monitoring during OLT.

Adult↗
PubMed1992

Oxygen consumption and mixed venous oxygen saturation monitoring during orthotopic liver transplantation.

Mixed venous oxygen saturation (SvO2) monitoring has been advocated for some critically ill patients. Patients with end-stage hepatic failure have oxygen consumption rates that are lower than normal. Using the Fick equation, oxygen consumption may be calculated if mixed venous and arterial oxygen tensions (and saturations), hemoglobin, and cardiac output are determined simultaneously. This report describes a unique pattern of changes in SvO2 and oxygen consumption in 7 patients undergoing liver transplantation. A previous study correlated plasma carbohydrate (glucose) levels with early hepatic graft survival. After induction, the 7 patients reported here had low oxygen consumption and high SvO2 values. The oxygen consumption rates decreased to the lowest point during the anhepatic phase and rose above baseline by the end of the case. The SvO2 and oxygen consumption data reported here follow the presence of presumed hepatic metabolic activity (increased CO2 and ionized calcium). Further research must be completed to determine whether these measurements indicate early hepatic nonfunction.

Adult↗
PubMed1992

Autologous blood donation: hemodynamics in a high-risk patient population.

Transfusion practices have changed dramatically in recent years as a result of the acquired immune deficiency syndrome crisis. The use of preoperative donation of autologous blood units has gained popularity. Healthy individuals tolerate phlebotomy well, experiencing a 2- to 5-percent incidence of vasovagal reactions. However, no systematic study of hemodynamic function during phlebotomy exists for patients who have major cardiovascular or multiple organ disease (high-risk patients). The following protocol examines blood pressure, heart rate, cardiac output, lead II electrocardiogram, and pulse oximetry in 123 patients donating a total of 224 units of blood in a new high-risk autologous blood donation program that was conducted in a postanesthesia care unit over the past 18 months. Changes in hemodynamic variables during phlebotomy were consistent with mild volume depletion; the changes did not result in overall differences in the courses of the groups. Significant numbers of patients exhibited systolic or diastolic hypotension, dysrhythmias, syncope, and tachycardia. Because tolerance for hypotension (vasovagal reactions) is decreased in patients with coronary artery disease, appropriate monitoring may be warranted to maximize the safety of elective phlebotomy. Further study is required to stratify risks and to determine which hemodynamic variables are predictive of adverse events.

Adolescent↗
PubMed1990

Anesthetic management of laser airway surgery.

This brief review of the anesthesiologist's role in the team effort necessary for the safe treatment of airway tumors by laser beam is provided to acquaint the referring physician or medical oncologist with some of the anesthesiologist's operating room concerns and how they are met. The necessity of bringing the patient to a level of maximum physiologic reserve prior to treatment becomes obvious with information gained by scanning this review. The referring physician or medical oncologist aids the patient and the anesthesiologist and surgeon by performing a thorough preoperative cardiopulmonary evaluation and therapeutic intervention, as indicated by patient need. The review includes a description of the actions of the carbon dioxide (CO2) and neodynium-yttrium aluminum garnet (YAG) lasers, "laser safety" for patients and personnel, monitoring, guarding the airway, ignition dangers, and comments on the use of jet and high frequency jet ventilation (HFJV).

Aluminum Silicates↗
PubMed1990

Sufentanil-midazolam anesthesia for coronary artery surgery.

The combination of benzodiazepines and high-dose narcotics has been reported to produce hypotension in patients undergoing coronary artery surgery. This study was performed to evaluate the cardiovascular effects of lower doses of the narcotic sufentanil administered with the benzodiazepine midazolam. Thirty adult patients with good ventricular function undergoing elective coronary revascularization received sufentanil, 2.5 micrograms/kg, and midazolam, 0.1 mg/kg, followed by infusions of sufentanil, 0.7 to 1.5 micrograms/kg/h, and midazolam, 0.07 to 0.15 mg/kg/h. Overall, stable hemodynamics were achieved before and after cardiopulmonary bypass (CPB). Patients who were not receiving preoperative beta-adrenergic blockade (n = 15) had increases from baseline heart rate and rate-pressure product after sternotomy, during aortic dissection, and after CPB that were not clinically significant. Five patients developed hypertension (increases greater than 20% over the baseline value), which was controlled with additional sufentanil or a vasodilator. Hypertension requiring vasodilator therapy did not occur in patients taking beta-adrenergic blockers. Blood pressure decreases exceeding 20% of the baseline value did not occur. Two of 15 patients receiving beta-blockers, versus 3 of 15 not receiving beta-blockers, developed ischemic electrocardiographic changes before CPB (NS); one of these patients without beta-blockade had a postoperative myocardial infarction. The results of this study show that the infusion of low doses of sufentanil with midazolam provides a hemodynamically safe and stable anesthetic for coronary artery surgery and avoids the hypotension seen when a high-dose narcotic is combined with a benzodiazepine.

Adrenergic beta-Antagonists↗
PubMed1990

Comparison of anesthetic techniques in patients undergoing heart valve replacement.

A prospective study of 324 adult patients undergoing operations requiring cardiopulmonary bypass for heart valve replacement was undertaken to determine the effect of anesthetic technique on outcome. Patients received one of three primary techniques: fentanyl (40-100 micrograms/kg), sufentanil (4-8 micrograms/kg), or diazepam (0.4-1 mg/kg) with ketamine (3-6 mg/kg). Supplemental inhalation anesthesia with enflurane, halothane, or isoflurane was used in 43.8% of cases. Patients in these anesthetic groupings had similar perioperative demographic and risk classifications. Although there were differences in the requirements for vasopressors postoperatively among the intravenous anesthetic agents, neither mortality rates, length of ICU stay, nor incidence of postoperative heart failure showed the advantage of any intravenous or inhalational agent. There were also no significant differences in the incidences of serious pulmonary, renal, or neurologic morbidity among primary anesthetic techniques nor among supplemental inhalation agents. Multivariate discriminant analysis of these data suggests that many factors are significantly more important than anesthetic technique as determinants of outcome after heart valve replacement.

Analysis of Variance↗
PubMed1990

Comparative effects of esmolol and verapamil in a model of a supraventricular tachydysrhythmia.

Supraventricular tachydysrhythmias are a commonly encountered clinical problem after cardiothoracic surgery. Current choices for acute drug therapy of these dysrhythmias include intravenous verapamil as well as esmolol, but no data yet exist comparing the relative negative dromotropic (atrioventricular [A-V] nodal blocking) and negative inotropic effects of these agents. The purpose of this study was to compare the effects of esmolol with those of verapamil on systemic hemodynamics, coronary blood flow, and cardiac contractility at doses that produce a similar ventricular response rate in an animal model of a supraventricular tachydysrhythmia. Rapid electrical stimulation (800 impulses/min) of the left atrium in 14 dogs resulted in a rapid and irregularly irregular ventricular rhythm. Esmolol or verapamil were administered by bolus and then infusion to incrementally slow the average ventricular rate. Regional myocardial contractility was measured using the end-systolic pressure-length relationship (Ees). At drug doses that produced similar decreases in ventricular rate, esmolol produced a greater decrease in contractility (Ees: 284 +/- 46 to 40 +/- 22 mmHg/mm, LV dp/dt: 2,400 +/- 450 to 1,360 +/- 450 mmHg/sec) compared with that following verapamil (Ees: 297 +/- 57 to 116 +/- 25 mmHg/mm, LV dp/dt: 2,040 +/- 580 to 1,950 +/- 520 mmHg/sec). This was accompanied by a modest decrease in cardiac output in the esmolol group (2,800 +/- 940 to 2,290 +/- 730 ml/min) compared with an unchanged cardiac output as ventricular rate slowed in verapamil-treated animals. Stroke volume increased significantly in the verapamil-treated animals (10.9 +/- 4.0 to 18.5 +/- 4.6 ml), but remained unchanged following esmolol.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1989

The impact of liver transplant programs on anesthesia personnel and services.

Liver transplantation procedures are being performed at an increasing number of hospitals throughout the United States. These procedures are challenging because of hemodynamic, metabolic, renal, and coagulation dysfunctions and may require prolonged periods of time for completion. Anesthesia departments are developing or managing teams of personnel to perform liver transplants. A survey was sent to directors of liver transplant anesthesia teams to investigate how teams were structured, compensated, and the impact of participation upon personnel involved. Thirty-nine centers were surveyed and 31 responded. The results showed an arithmetic doubling of cases for each of the last six years, most being performed at large medical centers (more than 759 beds) with populations served of 2 million or more. Cases were reported to average 13 hours in length and required a mean of five anesthesia personnel to complete. Compensation methods for work on a liver transplant team were variable; however, CRNAs and technicians received monetary reimbursement more frequently than physicians. Emotional responses of personnel were equally divided between favorable and unfavorable responses. Discriminate analysis showed that positive personnel attitudes were most closely tied to the presence of a protocol for breaks, call schedules, compensation, and the frequency of performing these cases. However, most protocols for personnel management were instituted in response to dissatisfaction. As the number of transplants per year increases, departments will need effective plans for personnel management to maximize departmental resources, increase research interest, and maintain personnel enthusiasm.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Does choice of anesthetic agent significantly affect outcome after coronary artery surgery?

A prospective study of 1094 consecutive adult patients undergoing coronary revascularization was undertaken to determine the effect of anesthetic technique on outcome. Patients received one of five primary techniques: high-dose fentanyl (greater than 50 micrograms/kg), moderate-dose fentanyl (less than 50 micrograms/kg), sufentanil (3-8 micrograms/kg), diazepam (0.4-1 mg/kg) with ketamine (3-6 mg/kg) or halothane (0.5-2.5% inspired concentration after thiopental induction). Supplemental inhalation anesthesia (enflurane, halothane, or isoflurane) was used in 60% of cases where the primary technique was intravenous based. Patients in the above anesthetic groupings had similar perioperative demographic and risk classifications. The overall incidence of postoperative myocardial infarction, postoperative low cardiac output state, and in-hospital death were 4.1, 5.6, and 3.1%, respectively. There were no significant differences in the incidence of these occurrences or in the incidence of serious pulmonary, renal, or neurologic morbidity or length of ICU stay among primary anesthetic techniques nor among supplemental inhalation agent groups. Multivariate discriminant analysis of this data suggests that a multitude of factors are significantly more important than anesthetic technique as determinants of outcome after coronary artery surgery.

Adult↗
PubMed1989

Effect of pulmonary artery catheterization on outcome in patients undergoing coronary artery surgery.

Previous studies have suggested that low-risk cardiac surgical patients may be safely managed without pulmonary artery catheterization (PAC). However, no prospective studies have determined whether PAC improves outcome in higher risk patients compared with that following central venous pressure (CVP) monitoring alone. The authors prospectively examined the incidence of and factors related to perioperative morbidity and mortality in 1094 consecutive patients undergoing coronary artery surgery managed with elective PAC (n = 537) or with CVP (n = 557). Perioperative risk factors and demographics that predict morbidity and mortality after cardiac surgery were used to quantify risk classification. Outcome was judged by length of ICU stay, occurrence of postoperative myocardial infarction, in-hospital death, major hemodynamic aberrations, and significant noncardiac systemic complications. No significant differences in any outcome variables were noted in any group of patients with similar quantitative risk classification managed with or without PAC, including those in the highest risk class. In addition, there were no significant differences in outcome among the 39 patients who would have been managed with CVP monitoring only, but who subsequently developed a clinical need for PAC based on the occurrence of serious hemodynamic events compared to patients who had PAC performed electively. This study suggests that PAC does not play a major role in influencing outcome after cardiac surgery, that even high-risk cardiac surgical patients may be safely managed without routine PAC, and that delaying PAC until a clinical need develops does not significantly alter outcome, but may have an important impact on cost savings.

Aged↗
PubMed1989

Comparison of viscoelastic measures of coagulation after cardiopulmonary bypass.

Postoperative hemorrhage remains a major cause of morbidity after cardiopulmonary bypass (CPB). Treatment remains empiric because of the need for immediate correction and the lack of availability of rapid intraoperative coagulation monitoring (except for ACT) at most institutions. Thrombelastography (TEG) and Sonoclot analysis (SCT) are measures of viscoelastic properties of blood which allow rapid intraoperative evaluation of coagulation factor and platelet activity as well as overall clot integrity from a single blood sample. Routine coagulation tests (RCT) including activated clotting time (ACT), prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen level (FIB), and platelet count (PLT) were determined and compared to TEG and SCT to assess which best predicted clinical hemostasis after CPB. Forty-two patients prospectively felt to be at high risk for excessive post-CPB bleeding had blood obtained for RCT, TEG, and SCT analysis before systemic heparinization and 30 min after protamine administration. Nine of 42 patients had excessive chest tube drainage, but no reoperations were required. After CPB, mean values for RCT were normal, but there were abnormalities in TEG and SCT parameters that reflect platelet-fibrin interaction. Both TEG and SCT were 100% accurate in predicting bleeding in these nine patients and, overall, both tests were significantly better predictors of postoperative hemorrhage than RCT. We conclude that viscoelastic determinants of clot strength may be abnormal after CPB and that SCT and TEG are, therefore, more useful than RCT for the detection and management of coagulation defects associated with CPB.

Adult↗