Biomedical subjects

Terri G Monk

Publications and source records attributed to Terri G Monk.

8 recordsLinked to original sources

PubMed2006

Processed EEG and patient outcome.

The era of research evaluating clinical outcomes associated with processed electroencephalogram (EEG) monitoring began with the first randomized trial of bispectral index monitoring (BIS) performed as part of the clearance process for approving routine clinical use of the BIS monitor by the United States Food and Drug Administration. Subsequent to this initial investigation, numerous other clinical investigations have demonstrated that the use of processed EEG monitors as an additional method of patient assessment and an aid to anaesthetic dosing can decrease anaesthetic usage and hasten recovery times. Because of the presumed association between anaesthetic effect and EEG changes, it is not surprising that the additional research has focused on the impact of processed EEG monitoring on postoperative outcomes and perioperative safety especially the prevention of intraoperative awareness.

Anesthesia↗

PubMed2005

Acute normovolemic hemodilution.

This article examines the technique of hemodilution and the consequences, benefits, efficacy, cost effectiveness, and future of acute normovolemic hemodilution.

Cost-Benefit Analysis↗

PubMed2005

Anesthetic management and one-year mortality after noncardiac surgery.

Little is known about the effect of anesthetic management on long-term outcomes. We designed a prospective observational study of adult patients undergoing major noncardiac surgery with general anesthesia to determine if mortality in the first year after surgery is associated with demographic, preoperative clinical, surgical, or intraoperative variables. One-year mortality was 5.5% in all patients (n = 1064) and 10.3% in patients > or =65 yr old (n=243). Multivariate Cox Proportional Hazards modeling identified three variables as significant independent predictors of mortality: patient comorbidity (relative risk, 16.116; P <0.0001), cumulative deep hypnotic time (Bispectral Index <45) (relative risk=1.244/h; P=0.0121) and intraoperative systolic hypotension (relative risk=1.036/min; P=0.0125). Death during the first year after surgery is primarily associated with the natural history of preexisting conditions. However, cumulative deep hypnotic time and intraoperative hypotension were also significant, independent predictors of increased mortality. These associations suggest that intraoperative anesthetic management may affect outcomes over longer time periods than previously appreciated.

Adult↗

PubMed2004

Preoperative recombinant human erythropoietin in anemic surgical patients.

Preoperative anemia in a surgical patient predisposes to poor outcomes and allogeneic blood transfusions. As an alternative to transfusions, pharmacologic management of preoperative anemia with recombinant human erythropoietin (rHuEPO) has been well studied in many different types of surgery. rHuEPO, when used alone or in combination with preoperative autologous blood donation before elective surgery, stimulates erythropoiesis and helps to avoid or reduce the need for allogeneic blood transfusions. The clinical evidence on preoperative use of rHuEPO in orthopedic, cardiac, and cancer surgery, as well as in bloodless surgery, is reviewed.

Anemia↗

PubMed2004

Influence of crystalloid and colloid replacement solutions on hemodynamic variables during acute normovolemic hemodilution.

STUDY OBJECTIVE: To determine whether, in maintaining normovolemia during acute normovolemic hemodilution, replacement fluid choice influences intraoperative hemodynamic variables. DESIGN: Prospective, randomized, single-blinded study. SETTING: Operating room of a tertiary-care university hospital. PATIENTS: 40 adult, ASA physical status I, II, and III patients scheduled for acute normovolemic hemodilution during radical prostatectomy. INTERVENTIONS: Patients were randomly assigned to four replacement fluid groups to receive 1) Ringer's lactate, 2) 5% albumin, 3) 6% dextran 70, or 4) 6% hetastarch. A standardized general anesthetic was used, and patients underwent moderate hemodilution to a target hemoglobin of 9 gm/dL. MEASUREMENTS: Hemodynamic variables were recorded using standard monitors, 5-lead electrocardiography, radial arterial catheter, and pulmonary artery catheter. Red blood cell loss for the entire hospitalization was calculated. MAIN RESULTS: Demographic and clinical outcome data were similar among the groups. During acute normovolemic hemodilution, heart rate and pulmonary capillary wedge pressure were unchanged from baseline in all groups, but patients receiving Ringer's lactate or albumin had greater declines in mean arterial pressure at the end of acute normovolemic hemodilution. Cardiac and oxygen consumption indexes were stable during acute normovolemic hemodilution, but oxygen extraction increased. CONCLUSIONS: During hemodilution, anesthetized patients maintain whole body oxygenation by increasing oxygen extraction. The administration of hetastarch or dextran as the replacement fluid during acute normovolemic hemodilution is associated with a more stable mean arterial pressure, but overall acute normovolemic hemodilution is well tolerated irrespective of the replacement fluid used.

Blood Loss, Surgical↗

PubMed2003

The influence of crystalloid and colloid replacement solutions in acute normovolemic hemodilution: a preliminary survey of hemostatic markers.

Acute normovolemic hemodilution (ANH), in which blood for autologous use is collected immediately before the onset of surgical blood loss, is a recommended autologous blood procurement technique for blood conservation. Both crystalloid and colloid replacement fluids have been used to maintain normovolemia during ANH, but few data are available to justify the use of a particular replacement fluid. Therefore, we designed a prospective, randomized study to determine if the replacement fluid choice affects various coagulation variables and perioperative blood loss. Forty adult patients, ASA physical status 1-3, scheduled for ANH during radical prostatectomy were randomly assigned to one of four replacement fluid groups: (a) Ringer's lactate, (b) 5% albumin, (c) 6% dextran 70 (DEX), or (d) 6% hetastarch (HES). After the induction of a standardized general anesthetic, all patients underwent ANH to a final hemoglobin level of 9 g/dL. Complete blood count, prothrombin time, partial thromboplastin time, fibrinogen, factors V and VIII levels, bleeding time, and thromboelastography (TEG measurements were obtained at similar time points in the procedure. When compared with baseline, activated partial thromboplastin time decreased and factor VIII levels increased in the postanesthesia care unit in both the Ringer's lactate and 5% albumin groups. The DEX and HES groups demonstrated a decrease in TEG maximum amplitude between preoperative and postanesthesia care unit measurements and TEG alpha (angle) was decreased from baseline in the DEX group. The changes in factor VIII, activated partial thromboplastin time, and TEG measurements indicate that HES and DEX may attenuate the hypercoagulability related to surgery.

Aged↗

PubMed2002

Intraoperative blood salvage: a mathematical perspective.

BACKGROUND: Intraoperative blood salvage (IBS) is one of several blood-conservation strategies employed to limit the use of allogeneic blood. IBS with mathematical modeling was studied to gain a better understanding of its benefits and limitations. STUDY DESIGN AND METHODS: Equations, based on a convergent geometric series, allowed the assessment of maximum allowable blood losses to avoid allogeneic RBC exposure in relationship to the fractional recovery of IBS. Such equations allowed us to calculate the potential "savings" in allogeneic RBC volume and to define better the efficiency of IBS. RESULTS: This model predicts that substantial amounts of RBCs (>2 units) can be recovered if there is large blood loss (e.g., >3000 mL) and if the minimal allowable Hct is low (e.g., 21%). As with other blood- conservation methods, this article shows that there are limits to the potential benefit of IBS for the avoidance of allogeneic RBC transfusion. CONCLUSION: IBS can be modeled with a convergent geometric series, and the amount of blood loss is dependent on the difference between the patient's starting Hct, the minimum allowable Hct, and the fractional recovery of RBCs. Such modeling illustrates the limited utility of IBS as a sole blood-conservation strategy.

Blood Loss, Surgical↗

PubMed2002

The use of bovine hemoglobin glutamer-250 (Hemopure) in surgical patients: results of a multicenter, randomized, single-blinded trial.

UNLABELLED: Hemoglobin-based oxygen carrier-201 (HBOC-201, hemoglobin glutamer-250 [bovine], Hemopure; Biopure Corporation, Cambridge, MA) is polymerized hemoglobin of bovine origin being developed as an oxygen therapeutic. In this study, we evaluated the tolerability of a single intraoperative dose of HBOC-201 in surgical patients. In a single-blinded, multicenter study, 81 patients were randomized to receive either a single infusion of HBOC-201 (55 patients) or an equivalent volume of lactated Ringer's solution (26 patients). Forty-two patients originally assigned to the HBOC-201 group received the entire planned treatment of only one of the following doses: 0.6, 0.9, 1.2, 1.5, 2.0, or 2.5 g/kg of body weight. Thirteen of the 55 patients in the HBOC-201-assigned group did not reach the trigger point for transfusion administration, and they were not included in the analysis. We studied clinical outcomes and compared hematologic findings, blood chemistry values, and blood use in the two treatment groups. There were no patient deaths in this study. No pattern of clinically significant laboratory abnormalities could be attributed to exposure to HBOC-201. In the HBOC-201 group, 2 patients had a transient increased concentration of serum transaminases and 6 had transient skin discoloration. One patient in the HBOC-201 group had mast cell degranulation with hypotension. Postoperatively, methemoglobin plasma concentrations increased in the HBOC-201 group in a dose-dependent manner, reaching maximal values of 3.7% +/- 3.2% (average of all doses given) on postoperative day 3. There was no difference in the mean number of allogeneic blood units transfused in the 2 groups (3.3 +/- 1.8 and 3.7 +/- 4.1 for the lactated Ringer's solution and HBOC-201 groups, respectively) over the course of hospitalization. The intraoperative administration of HBOC-201, up to a maximum of 245 g, was generally well tolerated. There was no relationship between HBOC-201 use and the number of allogeneic blood units transfused over the entire hospitalization course. The administration of HBOC-201 was associated with a delayed (third postoperative day) dose-dependent increase in the plasma methemoglobin concentration. We conclude that the intraoperative use of HBOC-201 was generally well tolerated. IMPLICATIONS: The intraoperative use of hemoglobin glutamer-250 (bovine) (HBOC-201, Hemopure was generally well tolerated. The administration of HBOC-201 was associated with a delayed increase in the plasma methemoglobin concentrations.

Adolescent↗