Treating patients with advanced heart failure in a community-based multidisciplinary team clinic is associated with significant reduction of healthcare utilization and costs

Background/Introduction

Heart failure (HF) care imposes a major economic burden, accounting for 1–3% of healthcare expenditure in developed countries. The greatest proportion of this cost (60%-70%) is accounted for by hospitalizations. A multidisciplinary team (MDT) approach in HF management is a key recommendation in international guidelines, to reduce mortality and HF hospitalization.

Purpose

To investigate whether a community-based MDT in an HF unit (HFU) had an impact on patients' healthcare utilization (HCU), and their associated costs.

Methods

A retrospective cohort study was conducted among members of the country's largest HMO, who visited at least once in a regional community-based HFU, established to provide ambulatory specialist care for patients with advanced HF, emphasizing patients in NYHA functional class III and IV, especially those with recurrent hospitalizations. HCU data were obtained from the HMO's claims data for 12 months before and after first HFU visit.

Results

Our cohort consisted of 962 patients, of whom 843 (87.6%) completed at least 12 months of follow-up, and 119 (12.4%) died during the 12 months following their first HFU visit. Both groups were comparable with regard to sex, socioeconomic status, Charlson comorbidity index, prevalence of IHD and/or carotid artery disease, AF, obesity, and chronic pulmonary disease. Those who died within 12 months were older, had more hypertension, hyperlipidaemia, diabetes, chronic renal disease and malignancy but were less likely to be smokers or to have supplementary health insurance coverage. There was a significant reduction in the total average HCU costs of the entire study population 12 months after the first HFU visit ($12,675 after vs. $13,188 before, p=0.014). However, while a reduction in these costs was observed among patients who completed 12 months of follow-up ($11,955 after vs. $13,112 before, p<0.001), an increase in these costs was observed among patients who died during follow-up ($17,774 after vs. $13,728 before, p=0.015). These opposite trends stem from a decrease ($3,540 after vs. $4,941 before, p<0.001) versus increase ($10,932 after vs. $6,733 before, p=0.002) in hospitalization costs of these groups, respectively, and an increase ($1,272 after vs. $928 before, p<0.001) versus decrease ($799 after vs. $1,116 before, p<0.001) in medication costs of these subgroups, respectively.

Conclusion(s)

Intensification of therapy by a dedicated MDT significantly reduced costs of HCU, predominantly because of a decrease in hospitalizations. This saving was noted even when including patients who died within a year of commencing treatment in our HFU (a group in whom healthcare costs are known to be excessive). A widespread establishment of dedicated community-based units, should be encouraged.

Funding Acknowledgement

Type of funding sources: None.

Simulation-Based Assessment Identifies Longitudinal Changes in Cognitive Skills in an Anesthesiology Residency Training Program

OBJECTIVES

We describe observed improvements in nontechnical or "higher-order" deficiencies and cognitive performance skills in an anesthesia residency cohort for a 1-year time interval. Our main objectives were to evaluate higher-order, cognitive performance and to demonstrate that simulation can effectively serve as an assessment of cognitive skills and can help detect "higher-order" deficiencies, which are not as well identified through more traditional assessment tools. We hypothesized that simulation can identify longitudinal changes in cognitive skills and that cognitive performance deficiencies can then be remediated over time.

METHODS

We used 50 scenarios evaluating 35 residents during 2 subsequent years, and 18 of those 35 residents were evaluated in both years (post graduate years 3 then 4) in the same or similar scenarios. Individual basic knowledge and cognitive performance during simulation-based scenarios were assessed using a 20- to 27-item scenario-specific checklist. Items were labeled as basic knowledge/technical (lower-order cognition) or advanced cognitive/nontechnical (higher-order cognition). Identical or similar scenarios were repeated annually by a subset of 18 residents during 2 successive academic years. For every scenario and item, we calculated group error scenario rate (frequency) and individual (resident) item success. Grouped individuals' success rates are calculated as mean (SD), and item success grade and group error rates are calculated and presented as proportions. For all analyses, α level is 0.05.

RESULTS

Overall PGY4 residents' error rates were lower and success rates higher for the cognitive items compared with technical item performance in the operating room and resuscitation domains. In all 3 clinical domains, the cognitive error rate by PGY4 residents was fairly low (0.00-0.22) and the cognitive success rate by PGY4 residents was high (0.83-1.00) and significantly better compared with previous annual assessments (P < 0.05). Overall, there was an annual decrease in error rates for 2 years, primarily driven by decreases in cognitive errors. The most commonly observed cognitive error types remained anchoring, availability bias, premature closure, and confirmation bias.

CONCLUSIONS

Simulation-based assessments can highlight cognitive performance areas of relative strength, weakness, and progress in a resident or resident cohort. We believe that they can therefore be used to inform curriculum development including activities that require higher-level cognitive processing.

[CHALLENGES IN LEARNING AND ASSESSING ANESTHESIA COGNITIVE AND NON-TECHNICAL SKILLS OF ANESTHESIOLOGISTS AND RESIDENTS IN ANESTHESIA]

There are major challenges in teaching and assessing skills expected from practicing anesthesiologists and residents in anesthesia training programs. It is important to measure two separate aspects of skilled performance in managing crises: implementing appropriate technical actions (technical performance), manifesting appropriate crisis solving, and management of anesthesia non-technical behaviors. Anesthesia nontechnical skills (ANTS) can be divided into two subgroups: (1) cognitive or mental skills (decision-making, planning, strategy, risk assessment, situation awareness); and (2) social or interpersonal affective skills (teamwork, communication, leadership). Competency assessment of nontechnical (i.e. cognitive and affective) and technical (i.e. psychomotor) skills, is extremely hard to accomplish using only traditional examinations. The Accreditation Council for Graduate Medical Education (ACGME) has instituted an initiative that requires training programs to assess each resident's competence in several domains of medical practice. The ACGME toolbox for evaluation lists simulation training as the most effective evaluation strategy for medical procedures. Simulation scripts or scenarios can and should be aimed to evaluate and assess the technical and non-technical capabilities of residents in anesthesia. Lapsed or deficient non-technical (cognitive) skills, can easily lead to cognitive errors in anesthesia. Understanding and correcting cognitive errors cannot be overemphasized. Cognitive errors are thought-process errors which lead to incorrect diagnoses and/or treatments. To achieve error-free levels, learning objectives and curriculum/teaching should be adjusted to address the deficiencies identified in these learning skills. To reach this aim, educational training in cognitive errors, meta-cognition, and de-biasing strategies is needed. However, there are still many questions regarding which errors are most important to address and which "adjustment" learning strategies are the most appropriate and effective in anesthesiology. Sharing scenarios can provide an objective comparative view of trainees in different residencies, and the potential for universal applicability of such scenarios, and learning from the mistakes detected. Communication and collaboration among centers involved in simulation programs (including sharing of validated scenarios) is important to the future of this technology and approach. In summary, cognitive and non-cognitive simulation-based skills assessment that included the so-called ANTS can help to identify areas of strength and weakness that can be used to guide the residency curriculum, especially regarding deficiencies in tasks requiring higher order processing. Any such deficiencies need to be addressed in any training program.

P2492The impact of diabetes mellitus newly diagnosed by glycated hemoglobin on outcomes in patients undergoing percutaneous coronary intervention - five years prospective follow up study

Background

Following percutaneous coronary interventions (PCI), both short and long terms ischemic outcomes are worse in patients with Diabetes Mellitus (DM) compared to those without DM.

Methods

We prospectively enrolled consecutive patients undergoing PCI. Glycated Hemoglobin (HbA1c) levels were assessed during the index hospitalization and newly diagnosed DM was defined as HbA1c≥6.5% in the absence of the previous diagnosis. The primary outcome was Major Adverse Cerebro and Cardiovascular Events (MACCE) defined as death, stroke, PCI or acute myocardial infarction at five years.

Results

Diabetes was previously diagnosed in 391 (34%) patients (DM group), 221 (19%) had newly diagnosed DM based on the HbA1c level and 539 (47%) did not have diabetes (Non-DM). In DM group HbA1c was 7.80±1.36% as compared with 7.62±1.30% in patients with newly diagnosed DM (p<0.001). These patients were younger (62.0±11.3 years) compared to DM (67.9±10.4 years) and non-DM (63.7±13.0) patients, p<0.001. five years MACCE rates were 37.8%, 65.5% and 42.5% in the non-DM, newly diagnosed DM and DM groups, respectively (p<0.001). Multivariate analysis showed that compared to non-DM, the adjusted two year hazard ratios for MACCE were 1.83 (p<0.001), 1.47 (p=0.01) and 0.52 (p=0.01) respectively in patients with known DM, newly diagnosed DM, and patients with newly diagnosis DM who had DM treatment started after PCI.

Conclusion

Newly diagnosed DM based on peri-procedural HbA1c is common and associated with increased short and long term risk for adverse outcomes. Our results show that the diagnosis and early treatment of diabetes in patients undergoing PCI should be included into the routine practice.

Construct Validity and Generalizability of Simulation-Based Objective Structured Clinical Examination Scenarios

BACKGROUND

It is not known if construct-related validity (progression of scores with different levels of training) and generalizability of Objective Structured Clinical Examination (OSCE) scenarios previously used with non-US graduating anesthesiology residents translate to a US training program.

OBJECTIVE

We assessed for progression of scores with training for a validated high-stakes simulation-based anesthesiology examination.

METHODS

Fifty US anesthesiology residents in postgraduate years (PGYs) 2 to 4 were evaluated in operating room, trauma, and resuscitation scenarios developed for and used in a high-stakes Israeli Anesthesiology Board examination, requiring a score of 70% on the checklist for passing (including all critical items).

RESULTS

The OSCE error rate was lower for PGY-4 than PGY-2 residents in each field, and for most scenarios within each field. The critical item error rate was significantly lower for PGY-4 than PGY-3 residents in operating room scenarios, and for PGY-4 than PGY-2 residents in resuscitation scenarios. The final pass rate was significantly higher for PGY-3 and PGY-4 than PGY-2 residents in operating room scenarios, and also was significantly higher for PGY-4 than PGY-2 residents overall. PGY-4 residents had a better error rate, total scenarios score, general evaluation score, critical items error rate, and final pass rate than PGY-2 residents.

CONCLUSIONS

The comparable error rates, performance grades, and pass rates for US PGY-4 and non-US (Israeli) graduating (PGY-4 equivalent) residents, and the progression of scores among US residents with training level, demonstrate the construct-related validity and generalizability of these high-stakes OSCE scenarios.

Simulation-based assessment to evaluate cognitive performance in an anesthesiology residency program

BACKGROUND

Problem solving in a clinical context requires knowledge and experience, and most traditional examinations for learners do not capture skills that are required in some situations where there is uncertainty about the proper course of action.

OBJECTIVE

We sought to evaluate anesthesiology residents for deficiencies in cognitive performance within and across 3 clinical domains (operating room, trauma, and cardiac resuscitation) using simulation-based assessment.

METHODS

Individual basic knowledge and cognitive performance in each simulation-based scenario were assessed in 47 residents using a 15- to 29-item scenario-specific checklist. For every scenario and item we calculated group error scenario rate (frequency) and individual (resident) item success. For all analyses, alpha was designated as 0.05.

RESULTS

Postgraduate year (PGY)-3 and PGY-4 residents' cognitive items error rates were higher and success rates lower compared to basic and technical performance in each domain tested (P < .05). In the trauma and resuscitation scenarios, the cognitive error rate by PGY-4 residents was fairly high (0.29-0.5) and their cognitive success rate was low (0.5-0.68). The most common cognitive errors were anchoring, availability bias, premature closure, and confirmation bias.

CONCLUSIONS

Simulation-based assessment can differentiate between higher-order (cognitive) and lower-order (basic and technical) skills expected of relatively experienced (PGY-3 and PGY-4) anesthesiology residents. Simulation-based assessments can also highlight areas of relative strength and weakness in a resident group, and this information can be used to guide curricular modifications to address deficiencies in tasks requiring higher-order processing and cognition.

Inconsistency between simultaneous blood pressure measurements in the arm, forearm, and leg in anesthetized children

STUDY OBJECTIVE

To determine the accuracy and precision of simultaneous noninvasive blood pressure (NIBP) measurement in the arm, forearm, and ankle in anesthetized children.

DESIGN

Prospective, randomized study.

SETTING

University medical center.

PATIENTS

101 ASA physical status 1 and 2 children (aged 1-8 yrs) scheduled for elective surgery with general anesthesia.

MEASUREMENTS

Simultaneous NIBP measurements were recorded at the arm, forearm, and ankle at 5-minute intervals.

MAIN RESULTS

The systolic blood pressure difference between the arm-forearm or the arm-ankle was within the ± 10% range in 63% and 29% of measurements, and within the ± 20% range in 85% and 67% of measurements, respectively. The diastolic blood pressure difference between the arm-forearm or the arm-ankle was within the ± 10% range in 42% and 44% and within the ± 20% range in 67% and 74% of measurements, respectively. In patients in whom the initial three NIBP measurements were within the ± 20% range between the forearm and arm, 86% of the subsequent measurements were also within that limit.

CONCLUSIONS

Forearm and ankle NIBP measurements are unreliable and inconsistent with NIBP measured in the arm of anesthetized children. These alternative BP measurement sites are not reliable in accuracy (comparison with reference "gold" standard) and precision (reproducibility).

Repair of concomitant valvular endocarditis using a single homograft

Definitive treatment of complicated bacterial endocarditis requires surgical operation. However, the extent of bacterial endocarditis has dictated that surgical options be individualized. There are several surgical approaches to treat bacterial endocarditis. Transesophageal echocardiography has provided an invaluable intraoperative aid to the surgical decision-making and quality assurance of the repair. We report a case in which a primary aortic homograft was used for concomitant aortic and mitral valve repair based on transesophageal echocardiography evaluation. This case provides a new surgical alternative that uses a single homograft to repair aortic and mitral valves.

Treating pulmonary hypertension post cardiopulmonary bypass in pigs: milrinone vs. sildenafil analog

Procedures using cardiopulmonary bypass (CPB) and aortic cross-clamping are associated with a variable degree of ischemia/reperfusion of the lungs, leading to acute pulmonary hypertension (PHT). The purpose of this study was to compare the effects of the sildenafil analog (UK343-664), a phosphodiesterase type V(PDEV) inhibitor, with milrinone, a PDE type III inhibitor, in a porcine model of acute PHT following CPB. After the pigs were anesthetized, pressure-tipped catheters were placed in the right ventricle and carotid and pulmonary arteries. Cardiac output was measured with an ultrasound probe on the ascending aorta. After heparinization and placement of aortic and right atrial cannulae, non-pulsatile CPB was instituted and cardioplegia administered following aortic cross-clamping. After 30 minutes, the clamp was removed and the animals re-warmed and separated from CPB in sinus rhythm. The animals were randomized to 3 groups, and 16 animals were studied to completion: milrinone (n=5) 50 μg/kg; sildenafil-analog (n=5) 500 μg/kg; and normal saline (NS) (n=6). Hemodynamic data were collected at baseline pre-CPB and, following termination of CPB, at baseline, 5, 10 and 30 minutes after administration of the drug. Pulmonary hypertension was present in all groups following CPB. After administration of the drugs, mean pulmonary artery pressure decreased in all 3 groups; however, only in the sildenafil-analog group did pulmonary vascular resistance(PVR) decrease by 35%, from 820 to 433 dynes · cm · sec-5at 5 minutes (p<0.05), and continued to be decreased at 10 minutes by 26% (P<0.05). Pulmonary selectivity was demonstrated with sildenafil-analog, because there were no similar changes in systemic vascular resistance(SVR) and no significant changes in systemic hemodynamics. Sildenafil-analog, a PDEV inhibitor, shows a promising role for managing the PVR increases that occur following CPB.

Supplemental oxygen compromises the use of pulse oximetry for detection of apnea and hypoventilation during sedation in simulated pediatric patients

OBJECTIVE

The goal was to assess the time to recognition of apnea in a simulated pediatric sedation scenario, with and without supplemental oxygen.

METHODS

A pediatric human patient simulator mannequin was used to simulate apnea in a 6-year-old patient who received sedation for resetting of a fractured leg. Thirty pediatricians participating in a credentialing course for sedation were randomly assigned to 2 groups. Those in group 1 (N = 15) used supplemental oxygen, and those in group 2 (N = 15) did not use supplemental oxygen. A third group (N = 10), consisting of anesthesiology residents (postgraduate years 2 and 3 equivalent), performed the scenario with oxygen supplementation, to ensure validity and reliability of the simulation. The time interval from simulated apnea to bag-mask ventilation was recorded. Oxygen saturation and Paco(2) values were recorded. All recorded variables and measurements were compared between the groups.

RESULTS

The time interval for bag-mask ventilation to occur in group 1 (oxygen supplementation) was significantly longer than that in group 2 (without oxygen supplementation) (173 +/- 130 and 83 +/- 42 seconds, respectively). The time interval for bag-mask ventilation to occur was shorter in group 3 (anesthesiology residents) (24 +/- 6 seconds). Paco(2) reached a higher level in group 1 (75 +/- 26 mmHg), compared with groups 2 and 3 (48 +/- 10 and 42 +/- 3 mmHg, respectively). There was no significant difference between the groups in oxygen saturation values at the time of clinical detection of apnea (93 +/- 5%, 88 +/- 5%, and 94 +/- 7%, respectively).

CONCLUSIONS

Hypoventilation and apnea are detected more quickly when patients undergoing sedation breathe only air. Supplemental oxygen not only does not prevent oxygen desaturation but also delays the recognition of apnea.

Administration of milrinone before ischemia, in the presence of beta-blockade, to treat metabolic impairment and myocardial stunning in pigs

BACKGROUND

We examined effects of phosphodiesterase type III inhibition on regional myocardial metabolism and global left ventricular function, during ischemia, in the presence of beta-blockade.

METHODS

Twenty-three pigs were randomized and studied to completion in four groups: C, did not receive drugs; M, received 50 microg/kg milrinone; E, received esmolol (150 microg/kg/min); E+M, received both. The left anterior descending artery (LADa) was then occluded for 15 min, followed by a 60-min reperfusion. Left ventricular (LV) function data obtained included LV pressures, cardiac output (CO), slope of end-systolic pressure-volume relationship (Emax), and dP/dT. Blood lactate concentrations were obtained from the aorta, LADa, and vein at baseline, end of occlusion, and during early (5 min) and late (1 h) reperfusion.

RESULTS

During ischemia, occlusion produced significant depression in LV dP/dT, Emax and concomitant elevation of LVEDP that persisted over early reperfusion in groups not treated with milrinone. After ischemia, measurements of CO were higher, with lower LVEDP and SVR; LV dP/dT and the Emax were higher, with lower LVEDP in the E+M group vs. the E group. Ischemic region lactate extraction during ischemia was better with E group vs. C group. Esmolol without or with milrinone was associated with nonsignificant lactate ischemic production during early reperfusion from baseline values.

CONCLUSION

We demonstrated that the pre-emptive administration of milrinone before ischemia was associated with less ischemic hemodynamic effects, without worsening the ischemic metabolic process. The combination E+M diminished ischemic metabolic impairment, and preserved left ventricular function and baseline hemodynamics.

Blue dyes, blue people: the systemic effects of blue dyes when administered via different routes

We report 4 patients who had facial color changes to a blue-green-gray color and decreased oxygen saturation as measured by pulse oximetry. Patient 1 received an intravenous (IV) methylene blue solution during a urologic procedure, and the remaining three patients were administered subcutaneous indigo carmine (patient 2) or Patent Blue (Patients 3 and 4) for axillary lymph node mapping. All patients had above normal methemoglobin levels. Two (Patients 2 and 3) had hypotension, and one (Patient 3) required IV ephedrine to restore hemodynamic stability. Patient 4 had a hypersensitivity reaction characterized by systemic urticaria and blue-colored subintegumentary edema due to the subcutaneous administration.

Treating Ischemic Left Ventricular Dysfunction With Hypertonic Saline Administered After Coronary Occlusion in Pigs

OBJECTIVE(S)

The effects of hypertonic saline on ventricular function are controversial, whether it is increasing contractility or preload. There are no data, however, on the influence of hypertonic saline in a stunned myocardium.

DESIGN

This study was prospective and randomized in order to analyze the effects of hypertonic saline solution (7.5%) on myocardial function and systemic hemodynamics in a porcine model of ischemia and reperfusion.

SETTING

A university teaching hospital, animal research laboratory.

PARTICIPANTS

Twelve adult domestic swine.

INTERVENTIONS

Myocardial stunning was produced by the complete occlusion of the proximal left anterior descending artery for 15 minutes followed by reperfusion. Five minutes after reperfusion, the animals were assigned to receive 4 mL/kg of hypertonic saline (n = 7) or normal saline (n = 5) over 10 minutes. Pressure-tipped catheters were placed in the left ventricular cavity and aorta. The dimensions of the left ventricle were measured with ultrasonic microcrystals. Cardiac output was measured with transit time ultrasound. Data were recorded continuously and compared before the occlusion, 5 minutes after reperfusion, and at the end of the infusion.

MEASUREMENTS AND MAIN RESULTS

Compared with baseline, ventricular function was significantly depressed after left anterior descending artery occlusion. Left ventricular dP/dT and its end-systolic pressure-volume slope decreased (38% and 52%, respectively; p < 0.05), with a concomitant increase in systemic vascular resistance. The administration of hypertonic saline significantly improved left ventricular function (Emax 1,422 +/- 198 mmHg/mL, and dP/dT 3.2 +/- 0.4 mmHg/s v normal saline group values of 1,156 +/- 172 and 2.5 +/- 0.5, respectively; p < 0.05), cardiac output (2.5 +/- 0.5 v 1.84 +/- 0.4 L/min, p < 0.05), and lowered systemic vascular resistance (from 28.8 +/- 2.3 to 23.5 +/- 1.4, p < 0.05), with no significant changes with normal saline administration.

CONCLUSIONS

After transient myocardial ischemia, hypertonic saline administered over a short period of time acts as an inodilator by increasing contractility while simultaneously lowering systemic vascular resistance.

Credentialing and certifying with simulation

Assessment and evaluation are integral parts of any educational and training process, and students at all levels of training respond by studying more seriously for the parts of the course or training that are assessed. To promote and enhance effective learning successfully, simulation and other teaching methods should be both formative and summative, because the ultimate goal is to ensure professional competence. This article describes a model of medical competence, and focuses on the use of medical simulation in assessment and evaluation of different levels of clinical competence using examples from experience.

Treating metabolic impairment and myocardial stunning with phosphodiesterase inhibitor type III, milrinone, administered prior to coronary artery occlusion in the presence of calcium channel blockade in pigs

This study examined milrinone effects on ischaemic myocardial metabolism and function with calcium blockade. We studied 15 pigs in 3 groups: group C received no drugs; group D received diltiazem 5 mg bolus followed by infusion; group D+M received diltiazem and milrinone (50microg/Kg). The left anterior descending (LAD) artery was then occluded for 15 minutes. Left ventricular (LV) function data obtained included rate, pressures, output, Emax, and dP/dT. Blood lactate was obtained from the LAD and circumflex vessels at baseline, end of occlusion, early (15 min) and late (1 hour) reperfusion. In group D+M, less depression of LV function occurred during ischaemia and early reperfusion. Lactate extraction in the LAD region was less negative in D+M group than in the group without milrinone during ischaemia and late reperfusion. We conclude the preemptive administration of milrinone prior to ischaemia added to calcium blockade improved myocardialfunction and ischaemic metabolic effects.

Treatment of ischaemic left ventricular dysfunction with milrinone or dobutamine administered during coronary artery stenosis in the presence of beta blockade in pigs †

BACKGROUND

This study examines the effects of phosphodiesterase type III (PDEIII) inhibition vs beta stimulation on global function of the left ventricle (LV) and systemic haemodynamics in a porcine model of acute coronary stenosis with beta blockade.

METHODS

A total of 18 adult swine were anaesthetized. Micromanometer-tipped catheters were placed in the ascending aorta and LV. Two pairs of ultrasonic dimension transducers were placed in the subendocardium on the short axis proximal to a left anterior descending (LAD) artery occluder and the long axis of the LV. Before ischaemia, i.v. esmolol was infused to decrease baseline heart rate (HR) by approximately 25%, and all animals received an esmolol infusion (150 microg kg(-1) min(-1)). Ischaemia was produced by reducing the flow in the LAD artery by approximately 80%, from 17(4) to 3(2) ml min(-1). Animals were randomized to receive (after esmolol) one of the following: no drug, sham only (Group 1, n=6), control (C); 50 microg kg(-1) i.v. milrinone (Group 2, n=6) followed by 0.375 microg kg(-1) min(-1) (M); or incremental doses of dobutamine (Group 3, n=6) every 10 min (5, 10 and 20 microg kg(-1) min(-1)) (D). Left ventricular function data obtained included HR, arterial and LV pressures, cardiac output (CO), Emax and dP/dT. Measurements were taken during five time periods: before ischaemia (at baseline, after esmolol) and every 10 min during ischaemia (at 10, 20 and 30 min).

RESULTS

The effects of beta blockade and ischaemia had a significant impact on contractility (Emax) in Group M and myocardial performance (left ventricular end-diastolic pressure, LVEDP) in all groups. Left ventricular function (Emax, CO, LVEDP and SVR) was better preserved when milrinone was added in Group M. A moderate dose of dobutamine (10 microg kg(-1) min(-1)) increased CO. Only the high dose (20 microg kg(-1) min(-1)) improved contractility (Emax), but at the expense of increased SVR. Also, LVEDP with either dose of dobutamine remained high and unchanged.

CONCLUSIONS

From our limited findings, it would appear that there may, theoretically, be some benefit for using milrinone in preference to other inotropic drugs in the presence of beta blockade. Milrinone administration should be considered in patients with acute ischaemic LV dysfunction and preexisting beta blockade before using other inotropic drugs such as beta stimulants.

The use of recombinant factor VIIa (NovoSeven) for treatment of active or impending bleeding in brain injury: broadening the indications

We report three patients with severe traumatic brain injury, both open and closed, who were treated with recombinant activated factor VII. This treatment was given in a desperate, last-ditch effort to save the life of patient 1, as a preventive or early treatment of a developing hematoma in patient 2, and as treatment of a threatening hematoma in patient 3. One of the three patients survived. During the past few years we have broadened the indications for recombinant activated factor VII and started using it as a preventive measure rather than as a "last line of defense." However, the potential complications of disseminated intravascular coagulation and thrombotic events, as well as the cost-effectiveness in view of the available evidence-based medicine, should be considered.

The validation process of incorporating simulation-based accreditation into the anesthesiology Israeli national board exams

BACKGROUND

The Israeli Board of Anesthesiology Examination Committee added a simulation-based Objective Structured Clinical Evaluation component to the board examination process. This addition was made in order to evaluate medical competence and considers certain domains that contribute to professionalism. This unique and new process needed to be validated.

OBJECTIVES

To validate and evaluate the reliability and realism of incorporating simulation-based OSCE into the Israeli Board Examination in Anesthesia.

METHODS

Validation was performed before the exam regarding Content Validity using the modified Delphi technique by members of the Task Force of the Israeli Board Examination Committee in Anesthesiology.

RESULTS

The examination has been administered six times in the past 3 years to a total of 145 examinees. The pass rate ranged from 62% (trauma) to 91% (regional anesthesia). The mean inter-rater correlations for the total score (all items), for the Critical checklist items score, and for the Global (General) rating were 0.89, 0.86 and 0.76, respectively. The inter-correlations between the five OSCE stations scores were significant (P< 0.01) only between Trauma & Ventilation for the Total score (r = 0.32, n=63), and between Resuscitation & Regional and OR-crisis for the Global score (r = 0.42 and 0.27, n=64 and 104, respectively). The correlation between the OSCE examination score and the success rate at each of the eight different clinical domains of the oral board examination did not reach statistical significance. Most participants (70-90%) found the difficulty level of the examination stations reasonable to very easy. All major errors, which were identified in the initial two exam periods, disappeared later in the next two exam periods.

CONCLUSIONS

The exam has gradually progressed from being an optional part of the oral board examination to a prerequisite component of this test. Other anesthesiology programs or medical professions can adopt the model described here.

Airway management of patient with Smith-Lemli-Opitz syndrome for gastric surgery: case report

A case of term, 5-day-old boy, with low birth weight of 2.4 kg, with Smith-Lemli-Opitz syndrome (SLOS) who was first scheduled for gastrostomy tube placement and later for pylorotomy, is discussed. General appearance of face and small chin showed possible difficulties during intubation, which are well known from the literature. Anesthetic plan included possibility of fiberoptic intubation. Mask induction and ventilation had been successful but attempts to intubate patient using fiberoptic bronchoscope had not been feasible and both procedures had been performed using laryngeal mask airway (LMA#1) with spontaneous ventilation without complications. In this case, we are showing the ability to secure the airway in a small infant with SLOS using LMA and the possibility to perform successfully surgery on the gastrointestinal tract.

Incorporating Simulation-Based Objective Structured Clinical Examination into the Israeli National Board Examination in Anesthesiology

We describe the unique process whereby simulation-based, objective structured clinical evaluation (OSCE) has been incorporated into the Israeli board examination in anesthesiology. Development of the examination included three steps: a) definition of clinical conditions that residents are required to handle competently, b) definition of tasks pertaining to each of the conditions, and c) incorporation of the tasks into hands-on simulation-based examination stations in the OSCE format, including 1) trauma management, 2) resuscitation, 3) crisis management in the operating room, 4) regional anesthesia, and 5) mechanical ventilation. Members of the Israeli Board of Anesthesiology Examination Committee assisted by experts from the Israel Center for Medical Simulation and from Israel's National Institute for Testing and Evaluation were involved in this process and in the development of the assessment tools, orientation of examinees, and preparation of examiners. The examination has been administered 4 times in the past 2 yr to 104 examinees and has gradually progressed from being a minor part of the oral board examination to a prerequisite component of this test. The pass rate ranged from 70% in resuscitation to 91% in regional anesthesia. The mean inter-rater correlations for all the checklist items, for the score based on the critical checklist items only, and for the general rating were 0.89, 0.86, and 0.76, respectively. The overall Kappa coefficients (the inter-rater agreement coefficient) for the total score and the critical checklist items were 0.71 and 0.76, respectively. The correlation between the total score and the general score was 0.76. According to a subjective feedback questionnaire, most (70%-90%) participants found the difficulty level of the examination stations reasonable to very easy and prefer this method of examination to a conventional oral examination. The incorporation of OSCE-driven modalities in the certification of anesthesiologists in Israel is a continuing process of evaluation and assessment.

Treatment with phosphodiesterase inhibitors type III and V: milrinone and sildenafil is an effective combination during thromboxane-induced acute pulmonary hypertension

OBJECTIVES

To evaluate the effects of phosphodiesterase type III and V (PDEIII and PDEV) inhibition on pulmonary and systemic haemodynamics in a porcine model of acute pulmonary hypertension.

METHODS

Twenty-four adult swine were anaesthetized with 1 MAC isoflurane and mechanically ventilated with an FI(O(2)) of 100%. Micromanometer-tipped catheters were placed in the ascending aorta, pulmonary artery and right ventricle. Pulmonary flow was measured with a perivascular probe using transit time ultrasound. Pulmonary hypertension was induced with a continuous infusion of the thromboxane analogue, U46619. The animals were then randomized to four groups: Group 1 (n=6) received 50 mg of sildenafil (PDEV inhibitor) diluted in water via an orogastric tube; Group 2 (n=6) received 50 microg kg(-1) of i.v. milrinone (PDEIII inhibitor); Group 3 (n=6) received sildenafil followed by milrinone; and Group 4 (n=6) received placebo via an orogastric tube.

RESULTS

Pulmonary hypertension was achieved in all animals. Calculated pulmonary vascular resistance decreased by an average of 36% after sildenafil (P<0.05), 41% after milrinone (P<0.05), and 61% with both drugs combined (P<0.05). Systemic vascular resistance decreased by 37% (P<0.05) with milrinone alone, and 36% (P<0.05) with milrinone and sildenafil combined but it was preserved in the sildenafil group. Cardiac output and right ventricular dP/dT were significantly improved after milrinone or both drugs combined, but not with sildenafil.

CONCLUSION

Milrinone and sildenafil are effective pulmonary vasodilators, with independent action and additive effect. Both drugs combined achieved a better haemodynamic profile, with greater pulmonary vasodilatation and increased contractility but without additional systemic vasodilatation. The systemic haemodynamic profile (systemic vasodilation, cardiac output, right ventricular dP/dT) is improved with milrinone but not with sildenafil.

Preservation of static and dynamic cerebral autoregulation after mild hypothermic cardiopulmonary bypass

BACKGROUND

Dysfunction of cerebral autoregulation might contribute to neurological morbidity after cardiac surgery. In this study, our aim was to assess the preservation of cerebral autoregulation after cardiac surgery involving cardiopulmonary bypass (CPB).

METHODS

Dynamic and static components of cerebral autoregulation were evaluated in 12 patients undergoing coronary artery bypass graft surgery, anaesthetized with midazolam, fentanyl, and propofol, and using mild hypothermic CPB (31-33 degrees C). Arterial pressure (ABP), central venous pressure (CVP), and blood flow velocity in the middle cerebral artery (CBFV) were recorded. The cerebral perfusion pressure (CPP) was calculated as a difference between mean ABP and CVP. Rapid decrease of CPP was caused by a sudden change of patients' position from Trendelenburg to reverse Trendelenburg. Cerebral vascular resistance (CVR) was calculated by dividing CPP by CBFV. Index of static cerebral autoregulation (CAstat) was calculated as the change of CVR related to change of CPP during the manoeuvre. Dynamic rate of autoregulation (RoRdyn) was determined as the change in CVR per second during the first 4 s immediately after a decrease in CPP, related to the change of CPP. Measurements were obtained after induction of anaesthesia, and 15, 30, and 45 min after termination of CPB.

RESULTS

No significant changes were found in CAstat or RoRdyn after CPB. Significant changes in CVR could be explained by concomitant changes in body temperature and haematocrit.

CONCLUSION

Autoregulation of cerebral blood flow remains preserved after mild hypothermic CPB.

Preliminary European results of local microwave hyperthermia and chemotherapy treatment in intermediate or high risk superficial transitional cell carcinoma of the bladder

INTRODUCTION

Superficial bladder cancer can be treated by transurethral resection (TUR) and adjuvant intravesical therapy. Intravesical bacillus Calmette-Guérin (BCG) has been proven to be more efficacious with respect to recurrence prevention than intravesical chemotherapy, although at the cost of more severe side effects. There is a need for a new treatment modality with higher efficacy and less toxicity. The subject of this study is the efficacy of local microwave hyperthermia and chemotherapy treatment in intermediate or high risk superficial transitional cell carcinoma (TCC) of the bladder.

PATIENTS AND METHODS

Ninety eligible patients received adjuvant treatment with a combination of mitomycin-C (MMC) and local microwave hyperthermia. All patients had multiple or recurrent Ta or T1 TCC of the bladder and were classified as intermediate or high risk according to EAU criteria. In total, 41 patients were BCG failures. The treatment regimen included 6 to 8 weekly sessions followed by 4 to 6 monthly sessions. Follow-up consisted of video-cystoscopy and urine cytology every 3 months. All patients were observed for 2 years.

RESULTS

Kaplan-Meier analyses of the total group (N = 90) indicated that 1 year after treatment only 14.3% (SE 4.5%) of all patients experienced a recurrence. After 2 years of follow-up the risk of recurrence was 24.6% (SE 5.9%). No progression in stage and grade was observed.

CONCLUSION

Microwave induced hyperthermia combined with MMC has promising value in intermediate or high risk superficial bladder cancer patients compared to literature data of BCG and/or intravesical chemotherapy, particularly where other treatments, i.e. BCG, have failed.

Inadvertent epidural injection of ephedrine in labor

Drugs mistakenly administered into the epidural space can have serious neurologic sequelae. This case reports the inadvertent administration of ephedrine during labor in a 17-year-old woman. The possible complications for both the mother and fetus are discussed and compared with other published literature reports.

Combined local bladder hyperthermia and intravesical chemotherapy for the treatment of high-grade superficial bladder cancer

OBJECTIVES

To evaluate the effectiveness of combined local bladder hyperthermia and intravesical chemotherapy for the treatment of patients with high-grade (G3) superficial bladder cancer.

METHODS

Patients with G3 bladder tumors (Stage Ta or T1) were treated with combined intravesical chemotherapy with mitomycin-C and local radiofrequency hyperthermia of the bladder wall. The patients were treated with either a prophylactic protocol (40 mg mitomycin-C) after complete transurethral resection of all tumors or with an ablative protocol (80 mg mitomycin-C) when visible tumor was seen on video-cystoscopy or bladder biopsies were positive for carcinoma in situ.

RESULTS

Combined chemo-thermotherapy was administered to 52 patients with high-grade superficial bladder cancer (40 patients with Stage T1 tumor, 11 with Ta, and 3 with concomitant or isolated carcinoma in situ). At a median follow-up of 15.2 months (mean 23, range 6 to 90), no stage progression to T2 or disease-related mortality had occurred. The bladder preservation rate was 86.5%. The prophylactic protocol was administered to 24 patients. After a mean follow-up of 35.3 months, 15 patients (62.5%) were recurrence free. The bladder preservation rate was 95.8%. The ablative protocol was administered to 28 patients. Complete ablation of the tumor was accomplished in 21 patients (75%). After a mean follow-up of 20 months, 80.9% of these patients were recurrence free. The bladder preservation rate for the ablative group was 78.6%.

CONCLUSIONS

Combined local bladder hyperthermia and intravesical chemotherapy has a beneficial prophylactic effect in patients with G3 superficial bladder cancer. Ablation of high-grade bladder tumors is feasible, achieving a complete response in about three quarters of the patients.

Propofol/remifentanil versus propofol alone for bone marrow aspiration in paediatric haemato-oncological patients

BACKGROUND

This prospective randomized study was designed to evaluate the effects of adding remifentanil to the standard propofol-based technique in the setting of paediatric haematology-oncology outpatient clinic.

METHODS

Eighty ASA III paediatric patients treated in the outpatient haematology-oncology clinic requiring bone marrow aspiration were randomly assigned either to the propofol (P) or the propofol/remifentanil (PR) group. The quality of anaesthesia and recovery were evaluated.

RESULTS

The total amount of propofol required to prevent patient movement was lower in the PR group. The time interval to eye opening and to home readiness was significantly lower in the PR group. Adverse respiratory events (RR < 10.min-1 or SpO2 < 90%) occurred significantly more in the propofol/remifentanil group.

CONCLUSIONS

The addition of remifentanil improved the conditions during the procedure and reduced the total amount of propofol, as well as the time to home readiness. However, the addition of remifentanil is associated with an increased risk of respiratory depression.

[First experiences in non-enhanced spiral computed tomography for diagnosis of acute flank pain]

Acute flank pain is commonly encountered in the emergency department, and often requires imaging to establish its cause. For decades intravenous urography and sonography have been the primary media for evaluating flank pain. Recently, noncontrast spiral CT (NCSCT) has been shown to be accurate and highly successful in diagnosing cause in such cases. We evaluated its use in the diagnosis of acute flank pain. During a 7-month period, 147 such cases had NCSCT imaging immediately after initial evaluation in the emergency department. Using a spiral CT scan without oral or i.v. contrast media, 109 of 147 cases were found to have ureteral stones, and 34 others to have other urological conditions unrelated to the cause of pain; 38 CT scans were negative for ureterolithiasis and in 14 non-urological disease was diagnosed. NCSCT is a valuable diagnostic technique for patients in the emergency department with flank pain. It rapidly and accurately detects ureteral stones causing renal colic and also detects extra-urinary causes of acute flank pain.

The American Society of Anesthesiologists' Physical Status: category V revisited

STUDY OBJECTIVE

To determine the perioperative mortality and intraoperative morbidity according to operative procedure and postoperative period for American Society of Anesthesiologists' Physical Status (ASA-PS) V category patients.

DESIGN

Retrospective chart review.

SETTING

University-affiliated medical center.

MEASUREMENTS AND MAIN RESULTS

The perioperative records of 111,051 consecutive anesthetized patients, from 1990 to 1997 were retrospectively reviewed. Data were collected and analyzed to determine ASA-PS classification, perioperative mortality, intraoperative morbidity, mortality according to operative procedure, and mortality postoperatively for ASA-PS V patients. At the University of Florida, 0.37% of our patients were ASA-PS V. Most had anesthesia for abdominal (26.2%), cardiothoracic (27.9%), cranial (12.3%), or diagnostic procedures (11.6%). The overall mortality rate decreased in 1993-1995 and 1995-1997, compared to 1990-1993, from 64.16 +/- 4.53 (+/-SD) to 46.7 +/- 9.5 and 56.8 +/- 1.1, respectively. The mortality rate decreased in the immediate postoperative period from 15.7 +/- 5.1 to 4.6 +/- 1.5 and 4.1 +/- 2. 8 intraoperatively, and from 42.5 +/- 1.8% to 22.1 +/- 5.1 and 26.8 +/- 1.8 within 24 hours postoperatively. The mortality rate increased from 0 +/- 0 to 7.4 +/- 3.9 and 15.5 +/- 4.9 (p < 0.05 for all), during the late postoperative period (>2 weeks, during hospitalization). Intraoperative morbidity (untoward events) was significantly higher for ASA-PS V patients than for ASA-PS IV patients only in emergency cases (11.1 +/- 4.8% vs. 5.5 +/- 1.4%).

CONCLUSIONS

The ASA-PS V classification is determined subjectively rather than objectively, and can be variable within its parameters, depending on the individual interpretation of ASA classification, patient population, case severity, surgical and anesthesia factors, and the year of the study. Even though immediate perioperative mortality decreased in our patient population, late postoperative mortality increased during the same time period, possibly demonstrating a shift in mortality time rather than an absolute decrease in overall mortality. Although the ASA-PS V category was never intended to be a predictor of outcome, it correlates with perioperative mortality as well as or even better than other classifications of mortality and morbidity. The decreased mortality in the ASA-PS V patient population may be related to different factors, which are beyond the scope of this study.

Transcranial Doppler monitoring compared with invasive monitoring of intracranial pressure during acute intracranial hypertension

OBJECTIVE

To determine whether a simple transcanial Doppler waveform variable-pulsatility difference (systolic - diastolic blood flow velocity) can serve as a measure of critical changes in cerebral perfusion.

METHODS

Thirteen pigs were anesthetized (anesthesia maintained with halothane) and ventilated to maintain normoxia and normocarbia. To measure mean arterial pressure, hemoglobin, and blood gases, the right carotid artery was cannulated. The right intracranial lateral ventricle was cannulated to measure and increase intracranial pressure; the right internal jugular vein was cannulated in 8 of 13 pigs to measure jugular venous oxygen saturation and to calculate cerebral arteriovenous oxygen content difference. Intracranial pressure was also monitored continuously with a subdural bolt in the contralateral frontal region, and blood flow velocity in the middle cerebral artery was measured with a transcranial Doppler probe on the right orbital region. Intracranial pressure was increased in increments of 10 to 20 mmHg by infusing saline through the ventriculostomy catheter until the transcranial Doppler indicated that blood flow velocity had ceased, at which point all variables were allowed to return to baseline. If mean arterial pressure failed to return to baseline, epinephrine, 0.01 to 0.1 microg/kg/min, was infused. Useful data were obtained from 8 pigs and were analyzed separately for pigs that received epinephrine (n = 4) and those that did not (n = 4).

RESULTS

Transcranial Doppler measurements correlated more closely with cerebral perfusion pressure = (mean arterial pressure - intracranial pressure) than with intracranial pressure. In the range of 30 to 60 mmHg, cerebral perfusion pressure correlated linearly with the pulsatility difference. The closest nonlinear correlation (third order polynomial relationship) was noted between cerebral perfusion pressure and pulsatility difference (r = 0.8, P < 0.001, n = 217), for the animals that did not receive epinephrine. When a cerebral perfusion pressure < 60 mmHg and a cerebral arteriovenous oxygen content difference > 6.5 vol% were used to define limits of abnormal, pulsatility difference was a sensitive and specific indicator of abnormality in either variable. Pulsatility difference of > 70 cm/sec had > 77.1% and 86.7% positive accuracy rate, and < 0% and 14.3% negative accuracy rate for abnormal cerebral perfusion pressure (CPP) and cerebral arterio-venous O2 (C[a-v]O2), respectively.

CONCLUSIONS

In pigs with induced diffuse intracranial hypertension, noninvasive transcranial Doppler waveform monitoring of pulsatility difference can identify increased cerebral oxygen extraction and dangerously decreased cerebral perfusion pressure.

Minimally invasive surgical treatment of female stress urinary incontinence

The purpose of this study was to evaluate the safety and efficacy of a new minimally invasive surgical procedure for the treatment of female stress urinary incontinence (SUI). Four miniature bone anchors, each attached to a suture, are inserted transvaginally into the retropubic bone using an inserter on each side of the urethra without opening the vaginal mucosa. Tying the suture on each ipsilateral side creates colposuspension, as is the aim of previously described procedures such as the Marshall-Marchetti-Krantz. Sixty-one women (mean age 52+/-SD 9.9 years) with a mean follow-up of more than 12 months (range 12-30 months) were treated for SUI. Fifty patients (82%) are dry, 7 (14%) reported great improvement and 4 are considered surgical failures. The data presented suggest that our new minimally invasive procedure provides an effective treatment for female SUI. Its main advantages over other procedures are the transvaginal approach and short operating time.

Aortic stenosis with end-stage liver disease: prioritizing surgical and anesthetic therapies

A 48-year-old man with end-stage liver disease and aortic stenosis (AS), was being evaluated for liver transplantation. This report focuses on the question of which medical problem to correct first, the end-stage liver disease or the AS. Risk factors for surgical correction of AS and liver transplantation are reviewed and discussed, and the surgical and anesthetic management strategies for this patient are outlined.

False low pulse oximetry reading associated with the concomitant use of a peripheral nerve stimulator and an evoked-potential stimulator

One of the sources of error in pulse oximetry readings is associated with an abnormal signal-to-noise ratio. The pulse oximeter distinguishes the light absorbance of arterial blood from that of other absorbers by differentiating between a constant component and a pulsating component. The pulsating component is almost exclusively the result of arteriolar bed pulsations. Because pulse oximetry is based on the assumption that arterial blood is the only pulsatile absorber, any other fluctuating phenomenon could constitute a source of error. We report a case in which a low pulse oximetry reading was associated with concomitant use of a pulse oximeter and a peripheral nerve stimulator on the same arm. Further tests conducted using a nerve stimulator and a sensory evoked potential stimulator with different amplitudes and frequencies confirmed the association and delineated the relationship between frequency and amplitude of stimulation and the degree of artificial desaturation. A theoretical explanation for this phenomenon is presented.

An alternative to radioactive microsphere for measuring regional myocardial blood flow, Part 2: Laser-Doppler perfusion monitor

OBJECTIVE

To compare measurements of regional myocardial blood flow volume between microsphere measurement of regional flow (0.5- to 2- g tissue sampling) and a potential alternative measure, local flow (1 mm3) in the microcirculation measured by laser-Doppler perfusion monitor.

DESIGN

Prospective, randomized, controlled.

SETTING

University research laboratory.

PARTICIPANTS

Pigs.

INTERVENTIONS

After anesthetization, in 5 pigs (25 to 30 kg), the left anterior descending coronary artery was isolated and its resting flow measured by a perivascular-Doppler flowmeter. Left ventricular pressure and first time derivative of left ventricular pressure were measured. The laser-Doppler probe needle (type N) (Model ALF-21, Transonic Systems, Inc, Ithaca, NY) was inserted 2 to 3 mm into the wall of the left ventricle, parallel to the coronary artery. All 5 pigs were subjected to 0 (control), 50% , 75%, and 100% constriction of the left anterior coronary artery.

MEASUREMENTS AND MAIN RESULTS

Measurements by radio-active microspheres correlated poorly with those by laser-Doppler and extremely poorly with those by perivascular Doppler flowmeter. For percent change from baseline in the constricted arterial zone, radioactive measurements correlated well with those by laser-Doppler but not those by Doppler flowmeter. Also, radioactive measurements of percent change in flow in the circumflex (nonconstricted) zone and laser-Doppler measurements in the constricted arterial zone did not correlate well.

CONCLUSIONS

Laser-Doppler can be recommended for experimental research to monitor local flow. These measurements may relate to change in regional flow during normal perfusion and hypoperfusion. Before the laser-Doppler perfusion monitor can be used clinically, tissue trauma from the 0.55-mm needle needs to be evaluated.

An alternative to radioactive microspheres for measuring regional myocardial blood flow, Part 1: Colored microspheres

OBJECTIVE

To compare measurements of regional myocardial blood flow between color and radioactive microspheres.

DESIGN

Prospective, randomized, controlled.

SETTING

University research laboratory.

PARTICIPANTS

Pigs.

INTERVENTIONS

Pigs underwent constriction of the left anterior descending artery, either incremental and then 0 constriction with epinephrine, 0.5 to 3 mu/kg/min (n = 5; "variable") or only 0% and 100% constriction without epinephrine (n = 4, "single"). Radioactive and color microspheres were injected simultaneously. For variable constriction, 5 colors (3 x 10(6)/mL) were tested in random order and, for single, red and yellow (6 x 10(6)/2 mL).

MEASUREMENTS AND MAIN RESULTS

Measurements of regional endocardial, epicardial, and transmural myocardial blood flow were compared by regression analysis (linear and nonlinear). With radioactive measurements as the point of reference, when regional flow was 50 to 150 mL/min/100 g, correlation was high (r = 0.85), although regression slope was low. With endocardial and epicardial flow between 30 and 100 mL/min/100 g, correlation was close (r = 0.84). Overall nonlinear correlation was higher with single than variable constriction (r = 0.72). When regional flow was less than 100 mL/min/100 g, linear correlation was r = 0.72. When transmural flow measured by color microspheres was less than 25 mL/min/100 g, correlation was high (r = 0.86) but, with endocardial or epicardial flow, low (r = 0.67). When transmural flow was greater than 100 mL/min/100 g, correlation was extremely low (r = 0.1; n = 26 data points). The overall correlations for regional endocardial and epicardial flows were also low, except in the ischemic zone.

CONCLUSIONS

Color and radioactive measurements correlate well during moderate and ischemic regional myocardial blood flow, ischemic blood flow requiring a higher concentration of color microspheres. A major limitation of using color microspheres is imprecision when flow is greater than 150 mL/min 100 g.