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.

Efficacy and cost-effectiveness of autologous blood predeposit in patients undergoing radical prostatectomy procedures.

OBJECTIVES: To assess the efficacy and cost-effectiveness of preoperative autologous blood donation (PAD) in radical prostatectomy procedures. METHODS: A retrospective 3-year review was performed of transfusion outcomes in radical prostatectomy procedures. Cost, benefits, and cost-effectiveness were established using a previously published Markov decision analysis model. RESULTS: Three hundred eighty-four (97%) of 394 patients predonated 3.5 +/- 0.6 (mean +/- SD) autologous blood units. Of these, 2.1 +/- 1.2 units (60%) were retransfused. Forty-two (11%) of 394 patients also received allogeneic blood. Autologous blood donors received only 0.2 +/- 0.6 allogeneic blood units, compared with 1.4 +/- 1.4 (p < 0.05) units transfused to patients who did not predonate. The net costs of PAD ranged from $83 to $303 per procedure. The life-expectancy benefit of PAD ranged from 0.05 to 0.07 days. The overall cost-effectiveness of PAD was estimated to be $1,813,000 per quality adjusted life-year saved. However, PAD was significantly more cost-effective for 2 unit donations ($531,000 per quality adjusted life-year saved). CONCLUSIONS: We conclude that autologous blood donation is an effective blood conservation strategy in elective radical prostatectomy. However, the cost-effectiveness of this practice compares unfavorably with that reported for other medical interventions. Alternative and more cost-effective strategies to reduce the need for allogeneic blood in this setting must be developed.

Laparoscopic pneumodissection: initial clinical experience.

OBJECTIVES: We evaluated the efficacy of a new laparoscopic dissecting instrument that fires intermittent bursts of high-pressure carbon dioxide to separate tissue along natural planes. METHODS: The pneumodissector (PD) was used in 2 patients undergoing laparoscopic procedures. Serum creatinine and bicarbonate were measured before and after the procedure, and arterial blood gases were measured before, during, and after use of the PD. Subjective assessment of the ease of dissection with the PD by the first assistant was recorded. RESULTS: Acidosis and hypercarbia were not observed with use of the PD. The PD facilitated dissection along the iliac vessels, around the kidney, and in the renal hilum. CONCLUSIONS: The PD is a feasible method for rapid, blunt dissection during laparoscopic procedures.

Carbon dioxide absorption during laparoscopic pelvic operation.

BACKGROUND: Several factors may influence the degree of carbon dioxide (CO2) absorption during laparoscopy. Hypercapnia as a result of excessive CO2 absorption may have adverse clinical effects. STUDY DESIGN: To identify factors associated with increased CO2 absorption, we retrospectively calculated the CO2 elimination in 65 adult patients who underwent operative pelvic laparoscopy. Increases in CO2 elimination were assumed to be indicative of CO2 absorption. The most commonly performed procedures were bladder neck suspension and pelvic lymphadenectomy. The median insufflation time was 165 minutes. An extraperitoneal approach was taken in 32 percent of the patients. RESULTS: Of patients evaluated with postoperative roentgenograms of the chest, 35 percent had subcutaneous emphysema and 9 percent had pneumomediastinum with or without pneumothorax. Multiple factorial analysis of the variance revealed that the extraperitoneal approach, development of subcutaneous emphysema, and increased duration of insufflation were independently associated with a greater increase in peak CO2 elimination. Insufflation time and subcutaneous emphysema had stronger effects in the extraperitoneal group. CONCLUSIONS: The risk factors for hypercapnia can be identified. Careful consideration of the patient's ability to tolerate hypercapnia should be made when planning extraperitoneal laparoscopy, especially if the procedure is likely to be prolonged. The clinical development of subcutaneous emphysema should alert the surgeon to the possibility of subsequent hypercapnia.

Laparoscopic pneumodissection: results in initial 20 patients.

BACKGROUND: The efficiency of laparoscopic procedures has been hindered by a lack of instrumentation for blunt tissue dissection. We evaluated here the efficacy of a new 5-mm laparoscopic dissecting instrument, a pneumodissector. This instrument allows the surgeon to use short bursts of high-pressure carbon dioxide to bluntly dissect fatty tissue. STUDY DESIGN: In 20 patients undergoing a variety of laparoscopic procedures, a 5-mm laparoscopic pneumodissector was used. Subjective assessment of the efficacy of the instrument was recorded. In addition, acid-base changes were measured by blood gas determination, and serum chemistries were obtained before, during, and after the procedure. RESULTS: The pneumodissector enhanced dissection of the kidney, ureter, and major blood vessels and shortened the operative time for laparoscopic nephrectomy. Although statistically significant changes in acidbase values occurred with use of the pneumodissector, these changes were not clinically significant and were no different than what is normally seen during carbon dioxide pneumoperitoneum. CONCLUSIONS: Laparoscopic pneumodissection is a safe and efficacious technique for rapid blunt tissue dissection.

The effect of prolonged pneumoperitoneum on renal function in an animal model.

BACKGROUND: Prolonged, increased intra-abdominal pressure (IAP) during laparoscopic surgery has been associated with oliguria and anuria. STUDY DESIGN: The objective of this study was to evaluate the effects of various levels of IAP on renal function. Ten groups of three adult female farm pigs were given a general anesthetic, followed by establishment of an IAP of 0, 5, 10, 15, or 20 mm Hg with CO2, 20 mm Hg with argon gas, abdominal wall lift device, renal vein occlusion (RVO), 15 mm Hg with CO2 plus dopamine administration at 2 microgram/kg/minute, or 20 mm Hg retroperitoneal CO2 insufflation. The following studies were recorded: baseline central venous pressure (CVP), pulmonary wedge pressure (PWP), cardiac output (CO), renal vein flow (RVF), renal artery pressure (RAP), selective urine output (UO), urinary osmolarity, and creatinine clearance; the parameters were repeated every 30 minutes for the four hours of the IAP study and two hours after release of the IAP. RESULTS: The results were analyzed within two main IAP groups: less than 15 mm Hg and greater than or equal to 15 mm Hg. There was no clinically significant variation in the CVP, PWP, and RAP. The CO decreased slightly and this was more significant in the greater than or equal to 15 mm Hg group. The RVF and UO decreased concomitantly and significantly in the greater than or equal to 15 mm Hg group. Even after two hours of desufflation, the RVF did not return to baseline, although the UO improved. Creatinine clearance decreased significantly in the greater than or equal to 15 mm Hg group. The RVO group exhibited similar changes in the study parameters as those seen in the greater than or equal to 15 mm Hg group, although the RVF did not improve on release of the renal vein in the RVO group. Changes were the same with an argon or CO2 IAP of 20 mm Hg. The abdominal wall lift device had an associated decrease in RVF at 15 KG force but no alteration in UO. Retroperitoneal insufflation resulted in the same decrease in RVF and UO as seen with the same IAP. Dopamine did not afford a protective effect on UO during an IAP of 15 mm Hg. CONCLUSIONS: The decreased UO during prolonged IAP greater than or equal to 15 mm Hg in the animal model is associated with a corresponding decrease in RVF, but does not appear to be associated with any permanent renal derangement nor any transient histologic changes.

Blood conservation strategies to minimize allogeneic blood use in urologic surgery.

Analysis of the net costs, efficacy, and cost-effectiveness of preoperative autologous blood donation (PAD), versus acute normovolemic hemodilution (ANH), in patients undergoing radical prostatectomy is presented. Currently, PAD is a standard of care for patients undergoing radical prostatectomy. Comparison of PAD with ANH showed no differences in risks or outcome, but ANH was less expensive. Hemodilution is a simple, safe, convenient, and effective alternative to PAD. The use of recombinant human erthropoietin in conjunction with PAD and ANH has optimized perioperative hematocrits and further minimized exposure to allogeneic blood. Intraoperative blood salvage, lower transfusion triggers, and other blood conservation strategies are discussed. The most cost-effective techniques currently available for decreasing allogeneic blood transfusions appear to be avoidance of blood loss, increased tolerance for decreased HCT levels, and autologous blood procurement via ANH.

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.

Acute hemodynamic effects of indigo carmine in the presence of compromised cardiac function.

This report describes the acute hemodynamic effects of indigo carmine in a surgical patient with compromised cardiac function. A 68-year-old woman with stable but severe cardiac dysfunction and renal artery stenosis was scheduled for an elective aortorenal bypass procedure. No hemodynamic instability occurred during the operation until the patient was administered intravenous (IV) indigo carmine 5 ml. At that time, the patient experienced an acute increase in afterload, which resulted in acute left ventricular failure documented by a decrease in cardiac output (CO) and an increase in pulmonary artery pressure (PAP). Until further studies defining the mechanism for its hypertensive side effect are performed, indigo carmine should be used with caution in patients with severe cardiac dysfunction.

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.

Functional MR imaging of the porcine kidney: physiologic changes of prolonged pneumoperitoneum.

BACKGROUND: Increased intraabdominal pressure (IPA) during laparoscopy has been associated with decreased urine output. The purpose of this study was to use a noninvasive MRI technique to measure renal vessel flow velocity and change in differential renal medulla and cortex perfusion during pneumoperitoneum. STUDY DESIGN: Six female farm pigs underwent general endotracheal anesthesia and dynamic imaging following left ventricular (LV) injection of Gd-DTPA, utilizing a dual echo gradient echo sequence. MRI was repeated after three hours of continuous 15 mm Hg pneumoperitoneum in three study pigs and after three hours of monitored general anesthesia without pneumoperitoneum in three control pigs. Renal artery and renal vein flow velocities were calculated using cine phase-contrast technique. Renal perfusion was independently measured by LV injection of radiolabelled microspheres. RESULTS: There was a decrease in mean renal vein flow velocity in the pneumoperitoneum group as compared to the control group. During pneumoperitoneum there was a similar percentage reduction in the perfusion of the cortex (-28%) and medulla (-31%); this corresponded with a decreased urine output. In addition, radiolabelled microspheres corroborated the similar decrease in both cortical and medullary perfusion rates during pneumoperitoneum. CONCLUSIONS: Prolonged IAP is associated with a decrease in renal vein flow velocity and urine output. There is a similar decrease in the renal medulla and cortex perfusion rates during pneumoperitoneum of 15 mm Hg.

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.

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.

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.

Electroencephalogram spectral edge frequency, lower esophageal contractility, and autonomic responsiveness during general anesthesia.

Both the electroencephalogram (EEG) spectral edge frequency (SEF) and lower esophageal contractility (LEC) indices have been reported to be useful indicators of anesthetic depth. We designed a prospective study to evaluate the relationship between changes in these two variables and objective measurements of physiologic responsiveness to surgical stress (i.e., changes in hemodynamic variables and plasma levels of norepinephrine, epinephrine, total catecholamines, and vasopressin). Eighty-nine consenting adult males undergoing radical prostatectomy procedures under a standardized general anesthetic technique were studied according to a randomized, single-blinded protocol. General anesthesia was induced with 30 micrograms/kg intravenous (i.v.) alfentanil, 2.5 mg/kg i.v. thiopental, and 0.1 mg/kg i.v. vecuronium, and subsequently maintained with 0.5 microgram/kg/min alfentanil, nitrous oxide (N2O) 67% in oxygen, and 0.8 microgram/kg/min vecuronium. Following retropubic dissection, 81 patients (92%) manifested acute hypertensive responses, with mean arterial pressure increasing from 90 +/- 14 to 122 +/- 14 mm Hg (mean +/- SD). This acute hypertensive response was treated with one of three different treatment modalities (20 to 60 micrograms/kg i.v. alfentanil, 0.5 to 2.0% inspired isoflurane, or 0.05 to 0.15 mg/kg i.v. trimethaphan) to return the mean arterial pressure to within 10% of the preincisional (baseline) value within 5 to 10 minutes. Although the mean arterial pressure, heart rate, and plasma levels of catecholamines and vasopressin significantly increased following the surgical stimulus, and decreased after adjunctive therapy, the EEG-SEF and LEC index (LECI) values did not significantly change during these study intervals. Furthermore, using a logistic regression analysis, we observed that preincision EEG-SEF and LECI values could not predict whether patients would manifest a hypertensive response. Therefore, the EEG-SEF and LECI were unreliable indicators of anesthetic depth.

Comparison of alfentanil and ketamine infusions in combination with midazolam for outpatient lithotripsy.

Sixty unpremedicated outpatients undergoing elective extracorporeal shock wave lithotripsy using an unmodified Dornier HM-3 lithotriptor were randomly assigned to receive an intravenous infusion of either alfentanil or ketamine as an adjuvant to midazolam for sedation and analgesia. Although both drug regimens allowed the maximal number of shock waves and energy level, the alfentanil group had significantly better calculi fragmentation (78% vs. 50% of patients with fragments less than 2 mm). Ketamine infusion provided superior intraoperative cardiorespiratory stability; however, it was associated with more disruptive movements (22 vs. 5) and dreaming (35% vs. 5%) during the procedure (P less than 0.05). Postoperatively, confusion also occurred more frequently in the ketamine-treated patients (31% vs. 5%, P less than 0.05). Alfentanil infusion was associated with more episodes of hemoglobin oxygen desaturation to less than 90% (12 vs. 2, P less than 0.05), itching (23% vs. 4%, P less than 0.05), and ability to recall intraoperative events (45% vs. 12%, P less than 0.05). The incidence of postoperative nausea was decreased (not significantly) in the alfentanil group (32% vs. 54%). The mean anesthesia time was similar in both groups; however, discharge times (means +/- standard deviations) were shorter in the alfentanil group (142 +/- 42 min vs. 161 +/- 31 min, P = 0.05). These data suggest that although both techniques proved effective for anesthesia in outpatients undergoing immersion lithotripsy, alfentanil is superior to ketamine as part of a sedative-analgesic technique because of the improved recovery profile and calculi fragmentation.

Comparison of transesophageal atrial pacing with anticholinergic drugs for the treatment of intraoperative bradycardia.

We compared the effectiveness of atropine, glycopyrrolate, and a transesophageal atrial pacing (TAP) stethoscope for treating intraoperative bradycardia in 64 unpremedicated patients receiving a standardized sufentanil/N2O/vecuronium anesthetic. Patients were allocated randomly to receive either atropine, 5 micrograms/kg (Group 1), glycopyrrolate, 2.5 micrograms/kg (Group 2), or transesophageal atrial pacing (Group 3) after the onset of bradycardia, defined as a heart rate of < or = 50 beats/min (or < or = 60 beats/min with concurrent hypotension). Bradycardia occurred in 15 patients of each treatment group. The time required for the heart rate to increase to > or = 70 beats/min was 270 (range 30-490), 270 (70-465), and 12 (2-30) s in Groups 1, 2, and 3, respectively. Although all patients in Group 3 responded to pacing at 150% of the threshold current, 10 patients in Group 1 and 8 patients in Group 2 required a second dose of anticholinergic medication before a heart rate response was observed. One patient in Group 2 required three doses, and another who did not respond even after four doses was treated with the TAP device. Bradycardia subsequently recurred in five patients in Group 1 and four patients in Group 2. Temporary recurrence of bradycardia occurred in seven patients in Group 3 due to outward migration of the pacing stethoscope. However, heart rates were more consistently maintained in paced patients. There were no significant differences in postoperative side effects between the three groups, or when compared with patients who did not receive treatment for bradycardia.(ABSTRACT TRUNCATED AT 250 WORDS)