Implementation of a standards-based anaesthesia record compliant with the health level 7 (HL7) clinical document architecture (CDA).

With the increasing use of anaesthesia information management systems (AIMS) there is the opportunity for different institutions to aggregate and share information both nationally and internationally. Potential uses of such aggregated data include outcomes research, benchmarking and improvement in clinical practice and patient safety. However, these goals can only be achieved if data contained in records from different sources are truly comparable and there is semantic inter-operability. This paper describes the development of a standard terminology for anaesthesia and also a Domain Analysis Model and implementation guide to facilitate a standard representation of AIMS records as extensible markup language documents that are compliant with the Health Level 7 Version 3 clinical document architecture. A representation of vital signs that is compliant with the International Standards Organization 11073 standard is also discussed.

Detection, evaluation, and management of preoperative anaemia in the elective orthopaedic surgical patient: NATA guidelines.

Previously undiagnosed anaemia is common in elective orthopaedic surgical patients and is associated with increased likelihood of blood transfusion and increased perioperative morbidity and mortality. A standardized approach for the detection, evaluation, and management of anaemia in this setting has been identified as an unmet medical need. A multidisciplinary panel of physicians was convened by the Network for Advancement of Transfusion Alternatives (NATA) with the aim of developing practice guidelines for the detection, evaluation, and management of preoperative anaemia in elective orthopaedic surgery. A systematic literature review and critical evaluation of the evidence was performed, and recommendations were formulated according to the method proposed by the Grades of Recommendation Assessment, Development and Evaluation (GRADE) Working Group. We recommend that elective orthopaedic surgical patients have a haemoglobin (Hb) level determination 28 days before the scheduled surgical procedure if possible (Grade 1C). We suggest that the patient's target Hb before elective surgery be within the normal range, according to the World Health Organization criteria (Grade 2C). We recommend further laboratory testing to evaluate anaemia for nutritional deficiencies, chronic renal insufficiency, and/or chronic inflammatory disease (Grade 1C). We recommend that nutritional deficiencies be treated (Grade 1C). We suggest that erythropoiesis-stimulating agents be used for anaemic patients in whom nutritional deficiencies have been ruled out, corrected, or both (Grade 2A). Anaemia should be viewed as a serious and treatable medical condition, rather than simply an abnormal laboratory value. Implementation of anaemia management in the elective orthopaedic surgery setting will improve patient outcomes.

The patient at risk for acute renal failure. Recognition, prevention, and preoperative optimization.

Despite major advances in critical care medicine and extracorporeal renal support, the treatment of established postoperative ARF remains unsatisfactory and costly. The essential elements of perioperative renal preservation are early recognition of high-risk patients, preoperative optimization of fluid status and cardiovascular performance, intraoperative maintenance of renal perfusion, and avoidance of nephrotoxins. Pharmacologic interventions directed at preventing postoperative ARF are under intense investigation but presently are limited to renal transplant surgery.

A randomized trial comparing acute normovolemic hemodilution and preoperative autologous blood donation in total hip arthroplasty.

BACKGROUND: The value of acute normovolemic hemodilution (ANH) as compared to preoperative autologous blood donation (PABD) in orthopedic surgery is unknown. Therefore, a prospective, randomized study was conducted to compare these techniques in patients undergoing primary total hip arthroplasty. STUDY DESIGN AND METHODS: ANH patients underwent phlebotomy for up to 3 units, or to a target Hct level of 28 percent after induction of anesthesia. PABD patients were asked to donate up to 3 units before admission. RESULTS: Mean baseline Hct levels were not different in ANH and PABD patients (39. 7 +/- 4.5 vs. 41.8 +/- 3.8%, p = 0.09). No difference was found in allogeneic blood exposure among ANH and PABD cohorts: 4 (17%) of 23 ANH patients received a total of 9 allogeneic blood units, compared to no allogeneic transfusions in the PABD cohort (p = 0.30). Total blood costs associated with ANH were significantly (p<0.05) lower than blood costs associated with PABD ($151 +/- 154 vs. $680 +/- 253, respectively). CONCLUSION: In patients undergoing total hip arthroplasty, ANH is safe, can be considered equivalent to PABD in effectively reducing exposure to allogeneic RBCs, and is less costly than PABD.

Dolasetron for the prevention of postoperative nausea and vomiting following outpatient surgery with general anaesthesia: a randomized, placebo-controlled study. The Dolasetron PONV Prevention Study Group.

In a multicentre, randomized, double-blind, placebo-controlled dose-ranging study, 1030 patients undergoing outpatient surgery with general anaesthesia received i.v. dolasetron mesylate (12.5, 25, 50, or 100 mg) or placebo. The principal outcome measure was the proportion of patients who were free of emesis or rescue medication for the 24-h period after the study drug was given; the subsidiary outcome measure was survival time without rescue medication. Effects on nausea were quantified using a visual analogue scale. Compared with placebo, a complete response was significantly higher when all four dolasetron doses were combined (49% vs. 58%, P =0.025). In females, dolasetron, 12.5-mg, dolasetron provided maximum clinical benefit (effectiveness compared with adverse events), with no additional benefit in complete response rates or nausea visual analogue scale scores at higher doses. No significant differences were observed in complete response for any dolasetron dose in males compared with placebo. The majority of adverse events reported were mild or moderate. Dolasetron provided well-tolerated, safe, and effective prophylaxis for post-operative nausea and vomiting with maximum effectiveness observed at a dose of 12.5 mg.

Blood conservation in patients undergoing non-cardiac surgery.

Concerns about the safety, inventory, and cost of allogeneic blood have led to a renewed interest in blood conservation. Autologous blood collection techniques, including preoperative autologous donation, acute normovolemic hemodilution, and perioperative blood recovery are routinely used as alternatives to allogeneic transfusion. In the future, these techniques may be combined with pharmacological strategies, such as presurgical erythropoietin therapy or red cell substitutes, to reduce further the need for allogeneic blood.

A randomized trial of acute normovolemic hemodilution compared to preoperative autologous blood donation in total knee arthroplasty.

The value of acute normovolemic hemodilution (ANH) compared to preoperative autologous blood donation (PAD) in elective surgery is controversial. We therefore conducted a prospective, randomized study to compare these techniques in patients undergoing total knee arthroplasty. ANH patients underwent up to 4 units phlebotomy or to a target hematocrit level of 28% after induction of anesthesia. PAD patients were asked to donate 1 (unilateral) or 2 (bilateral, revisions) units before admission. Mean baseline hematocrit levels were not different between ANH and PAD patients (40.6+/-4.1 vs. 38. 4+/-3.4, p = 0.09). Eight (73%) of 11 patients undergoing bilateral revision procedures received a total of 22 allogeneic blood units, whereas only 3 (14%) of 21 patients undergoing primary, unilateral procedures received a total of 3 allogeneic units (p = 0.002). We found no differences in allogeneic blood transfusions between ANH and PAD cohorts for all (n = 32) patients (1.0+/-1.2 vs. 0.6+/-1.4, p = 0.45), for unilateral knee (n = 21) replacement (0.25+/-0.46 vs. 0.08+/-0.28, p = 0.29), or for bilateral/revision (n = 11) procedures (1.9+/-1.3 vs. 2.5+/-1.9, p = 0.53). We conclude that each technique is equally effective in reducing allogeneic blood exposure. Patients undergoing revision or bilateral knee arthroplasties require adjunctive therapy to autologous blood procurement to further reduce allogeneic blood exposure.

A prospective randomized comparison of three blood conservation strategies for radical prostatectomy.

BACKGROUND: Preoperative autologous blood donation is a standard of care for elective surgical procedures requiring transfusion. The authors evaluated the efficacy of alternative blood-conservation strategies including preoperative recombinant human erythropoietin (rHuEPO) therapy and acute normovolemic hemodilution (ANH) in radical retropubic prostatectomy patients. METHODS: Seventy-nine patients were prospectively randomized to preoperative autologous donation (3 U autologous blood); rHuEPO plus ANH (preoperative subcutaneous administration of 600 U/kg rHuEPO at 21 and 14 days before surgery and 300 U/kg on day of surgery followed by ANH in the operating room); or ANH (blinded, placebo injections per the rHuEPO regimen listed previously). Transfusion outcomes, perioperative hematocrit levels, postoperative outcomes, and blood-conservation costs were compared among the three groups. RESULTS: Baseline hematocrit levels were similar in all groups (43%+/-2%). On the day of surgery hematocrit decreased to 34% +/-4% in the preoperative autologous donation group (P < 0.001), increased to 47%+/-2% in the rHuEPO plus ANH group (P < 0.001), and remained unchanged at 43%+/-2% in the ANH group. Allogeneic blood exposure was similar in all groups. The rHuEPO plus ANH group had significantly higher hematocrit levels compared with the other groups throughout the hospitalization (P < 0.001). Average transfusion costs were significantly lower for ANH ($194+/-$192) compared with preoperative autologous donation ($690+/-$128; P < 0.001) or rHuEPO plus ANH ($1,393+/-$204, P < 0.001). CONCLUSIONS: All three blood-conservation strategies resulted in similar allogeneic blood exposure rates, but ANH was the least costly technique. Preoperative rHuEPO plus ANH prevented postoperative anemia but resulted in the highest transfusion costs.

Perioperative myocardial ischemic episodes are related to hematocrit level in patients undergoing radical prostatectomy.

BACKGROUND: The anemia associated with perioperative blood conservation has raised concerns regarding the safety of these strategies in patients with ischemic cardiovascular disease. Therefore the relationship between hematocrit level and myocardial ischemic episodes in a group of elderly patients undergoing elective noncardiac surgery was studied. STUDY DESIGN AND METHODS: One hundred ninety patients undergoing radical prostatectomy were randomly assigned to one of three blood conservation groups: preoperative autologous blood donation, acute normovolemic hemodilution, and preoperative erythropoietin therapy with acute normovolemic hemodilution. Patients underwent ambulatory electrocardiography monitoring to evaluate for myocardial ischemia at randomization (baseline), 7 days preoperatively, throughout surgery, and for 24 hours after surgery. RESULTS: Myocardial ischemic episodes occurred in 61 (34%) of 181 evaluable patients. Patients with hematocrit levels < 28 percent immediately after surgery were significantly (p = 0.05) more likely to have intraoperative and postoperative ECG ischemic episodes. Intraoperative ischemia and tachycardia correlated (r = 0.21, p = 0.008) with hematocrit levels. Hematocrit levels after surgery were associated with postoperative ischemia (r = 0.14, p = 0.03) and duration of myocardial ischemic episodes (r = 0.14, p = 0.04). After adjusting for other risk factors, intraoperative tachycardia episodes, hematocrit level < 28 percent immediately after surgery, and risk factors for coronary artery disease were independently associated with the likelihood of intraoperative ischemia (r = 0.36, p = 0.002, area under receiver operating characteristic curve = 0.73). Similarly, tachycardia episodes and hematocrit levels < 28 percent immediately after surgery were independently associated with ischemic episodes during the first postoperative day (r = 0.30, p = 0.004, area under receiver operating characteristic curve = 0.71). CONCLUSION: A hematocrit level < 28 percent is independently associated with risk for myocardial ischemia during and after noncardiac surgery. Avoidance of cardiac complications may require higher transfusion thresholds, closer attention to tachycardia, or better monitoring for ischemia.

Simultaneous bilateral percutaneous nephrolithotomy with subarachnoid spinal anesthesia.

We report our experience performing simultaneous bilateral percutaneous nephrolithotomy (SBPN) in four patients with large stone burdens in both kidneys. We modified the previously described approach by combining SBPN with subarachnoid Duramorph (preservative-free morphine sulfate) in an effort to decrease postoperative discomfort and shorten the duration of hospitalization. These patients (study group) were then compared with a contemporary group of four patients with similar bilateral stone burdens who underwent staged bilateral percutaneous nephrolithotomies (PCNs) (control group). The comparison showed a marked advantage in hospital stay (4.8 days for the study group v 11 days for the control group) and postoperative narcotic requirement (27.5 mg of meperidine for the study group v 533 mg for the control group). All four patients were rendered stone free. This method of treatment for large bilateral renal calculi with the addition of subarachnoid Duramorph resulted in less postoperative discomfort, less morbidity, and a more rapid recovery than staged PCN or sandwich PCN/SWL/PCN.

Remifentanil versus propofol as adjuncts to regional anesthesia. Remifentanil 3010 Study Group.

STUDY OBJECTIVE: To compare the safety and efficacy of remifentanil and propofol as adjuncts to regional anesthesia in patients undergoing orthopedic or urogenital surgery. DESIGN: Prospective, randomized study. SETTING: Multicenter university hospitals. PATIENTS: 107 ASA physical status I, II, and III adult patients who underwent orthopedic or urogenital surgery with axillary, ankle, or spinal block. INTERVENTIONS: Patients were randomized to receive either an infusion of remifentanil 0.2 microg/kg/min or propofol 100 microg/kg/min 5 minutes before nerve block placement. The infusions were decreased by 50% on block completion, increased by 50% for patient discomfort, and decreased by 50% for hypoventilation (< 8 breaths/min) or hemodynamic instability. MEASUREMENTS AND MAIN RESULTS: Pain, discomfort, anxiety, and sedation were assessed by both patient and investigator. Vital signs and adverse events were recorded. Fewer patients in the remifentanil group experienced pain during block placement (6%), and were oversedated (7%) than patients in the propofol group (23% and 26%, respectively; p < 0.05). Hypoventilation during and after block placement (21% and 25%, respectively) and nausea and vomiting during and after block placement (60% and 21%, respectively) were more common in the remifentanil group than in the propofol group (0% and 3%; 17% and 6%, respectively; p < 0.05). The incidence of hypoventilation in remifentanil-treated patients was higher in patients over 65 years of age (p < 0.05), but was transient, resolving within minutes of discontinuing the infusion. CONCLUSIONS: At the doses studied, remifentanil was more effective than propofol in minimizing pain without producing excessive sedation. Remifentanil was associated with more transient respiratory depression and short-term nausea. Our findings indicate that the initial remifentanil rate should be 0.1 microg/kg/min (50% lower than the study's initial rate) and should be further decreased an additional 50% in the elderly to minimize adverse effects.

Acute normovolemic hemodilution.

Acute normovolemic hemodilution was described to be useful as a blood conservation strategy more than 25 years ago, yet seldom is practiced today. The benefit of acute normovolemic hemodilution is perceived to be modest and the technique is not taught in anesthesia or surgery training programs. Acute normovolemic hemodilution is an autologous blood procurement strategy that is superior to the predeposit of autologous blood for several reasons: Acute normovolemic hemodilution is less costly, with an average cost of $25 per unit compared with $175 per unit predonated; and acute normovolemic hemodilution units are reinfused to patients before the patient leaves the operating room, so that the units need not be tested and there is no possibility of administrative error. Emerging clinical studies now show that acute normovolemic hemodilution is equivalent to predonated autologous blood in reducing allogeneic blood exposure in patients undergoing elective surgery.

Erythropoietin therapy in the perioperative setting.

Recombinant human erythropoietin has been approved for use in patients undergoing autologous donation in Japan, Europe, and Canada since 1993, 1994, and 1996, respectively, and for perisurgical adjuvant therapy without autologous donation in Canada and the United States since 1996. Early clinical trials of erythropoietin therapy in the setting of autologous donation have provided important information regarding clinical safety, erythropoietin dose, and erythropoietic response. Later trials of perisurgical erythropoietin therapy without autologous donation provided data on efficacy (reduced allogeneic blood exposure) that led to approval of erythropoietin in patients undergoing surgery. However, the erythropoietin doses (300 U/kg subcutaneous x14 days) used in these trials, and their subsequent inclusion in labeling for the use of this product, are costly and tedious to administer. A recent study reported that a weekly regimen of erythropoietin (600 U/kg) for 4 weeks is less costly but just as effective at reducing allogeneic blood exposure in elective orthopaedic surgery. The most cost effective regimen that has been shown to minimize allogeneic exposure is preoperative erythropoietin therapy (600 U/kg subcutaneous weekly x2 and 300 U/kg subcutaneous on day of surgery) coupled with acute normovolemic hemodilution in patients undergoing radical retropubic prostatectomy. A similar regimen of erythropoietin therapy in patients undergoing coronary artery bypass grafting (2500 U/kg subcutaneous in divided doses for 2 weeks preoperatively) coupled with hemodilution also was effective. Low dose erythropoietin therapy coupled with acute normovolemic hemodilution ultimately may be shown to be cost equivalent to the predonation of three autologous blood units before elective surgery.

Oxygen carriers as blood substitutes. Past, present, and future.

Prospects for safe and effective blood substitutes are promising, based on clinical trial results of soluble hemoglobin solutions and emulsion of perfluorocarbins. Advantages of blood substitutes include sterilization of viral and bacterial contaminants, room temperature storage, a long shelf life, and absence of ABO and other red cell antigens. Projected arenas for their use include not only military applications but also trauma medicine and elective surgical settings, coupled with acute normovolemic hemodilution. Applications of perfluorocarbons are limited by the need for 100% FIO2. A significant challenge facing development of hemoglobin solutions is their effect on vascular tone through smooth muscle constriction. Development of second or third generation hemoglobin solutions may be necessary so that hemoglobin solutions more closely mimic cellular hemoglobin's nitric oxide binding properties. Optimizing O2 delivery to ischemic tissues and organs may lead to regulatory approval of these agents in this setting before their approval as blood substitutes.

Acute normovolemic hemodilution can replace preoperative autologous blood donation as a standard of care for autologous blood procurement in radical prostatectomy.

UNLABELLED: Predonation of autologous blood (PAD) is a standard of care for patients undergoing radical prostatectomy, but recent studies have shown that PAD is not cost-effective. Acute normovolemic hemodilution (ANH) is an alternative autologous blood procurement technique that is much less costly than PAD. We compared the efficacy and costs of ANH alone to ANH combined with PAD. Two hundred-fifty patients who predonated fewer than 3 units of autologous blood before radical prostatectomy underwent ANH to a target hematocrit of 28%. Perioperative hematocrit levels, transfusion outcomes and costs, and postoperative outcomes were compared for patients who predonated 0, 1, or 2 units of blood before surgery. A computer model was used to estimate the savings in red blood cells (RBC) associated with each autologous intervention. ANH alone resulted in a 21% allogeneic transfusion rate and contributed a mean net savings of 112 mL RBC in blood conservation (equivalent to 0.6 unit of blood). The addition of 1 or 2 units of PAD reduced allogeneic exposure rates to 6% or 0%, respectively. Overall, patients who predonated blood had a mean net loss of 198 mL of RBC (equivalent to 1 blood unit), due to both an absence in compensatory erythropoiesis and to the wastage of 60% of the blood units donated. Patients who underwent ANH alone had a 60% reduction in mean total transfusion costs ($103 +/- $102) compared with patients who predeposited 2 units of autologous blood in addition to ANH ($269 +/- $11, P < 0.05). We conclude that ANH can replace PAD as an autologous blood option because it is less costly and equally effective. A combination of ANH and PAD can further decrease allogeneic blood exposure, but it increases transfusion costs and wastage. IMPLICATIONS: A patient's own blood can be obtained for use in surgery by predonation or acute normovolemic hemodilution on the day of surgery. Both blood collection techniques decrease the need for blood bank transfusions, but acute normovolemic hemodilution is less expensive and more convenient for patients.

Blood substitutes: evolution and future applications.

The development of oxygen-carrying blood substitutes has progressed significantly in the last decade with phase I and phase II clinical trials of both hemoglobin-based and perfluorocarbon-based oxygen carriers nearing completion. As these products approach clinical use it is important for the laboratory medicine community to be aware of their effects on routine laboratory testing and the settings in which they might be used. Here we review the forces driving the development of oxygen-carrying blood substitutes, the clinical settings in which they might be used, the major categories of oxygen carriers in clinical trials, and the challenges faced by these products as they approach clinical use.

Effect of hemoglobin- and Perflubron-based oxygen carriers on common clinical laboratory tests.

Polymerized hemoglobin solutions (Hb-based oxygen carriers; HBOCs) and a second-generation perfluorocarbon (PFC) emulsion (Perflubron) are in clinical trials as temporary oxygen carriers ("blood substitutes"). Plasma and serum samples from patients receiving HBOCs look markedly red, whereas those from patients receiving PFC appear to be lipemic. Because hemolysis and lipemia are well-known interferents in many assays, we examined the effects of these substances on clinical chemistry, immunoassay, therapeutic drug, and coagulation tests. HBOC concentrations up to 50 g/L caused essentially no interference for Na, K, Cl, urea, total CO2, P, uric acid, Mg, creatinine, and glucose values determined by the Hitachi 747 or Vitros 750 analyzers (or both) or for immunoassays of lidocaine, N-acetylprocainamide, procainamide, digoxin, phenytoin, quinidine, or theophylline performed on the Abbott AxSym or TDx. Gentamycin and vancomycin assays on the AxSym exhibited a significant positive and negative interference, respectively. Immunoassays for TSH on the Abbott IMx and for troponin I on the Dade Stratus were unaffected by HBOC at this concentration. Tests for total protein, albumin, LDH, AST, ALT, GGT, amylase, lipase, and cholesterol were significantly affected to various extents at different HBOC concentrations on the Hitachi 747 and Vitros 750. The CK-MB assay on the Stratus exhibited a negative interference at 5 g/L HBOC. HBOC interference in coagulation tests was method-dependent-fibrometer-based methods on the BBL Fibro System were free from interference, but optical-based methods on the MLA 1000C exhibited interferences at 20 g/L HBOC. A 1:20 dilution of the PFC-based oxygen carrier (600 g/L) caused no interference on any of these chemistry or immunoassay tests except for amylase and ammonia on the Vitros 750 and plasma iron on the Hitachi 747.