Processed electroencephalography: impact of patient age and surgical position on intraoperative processed electroencephalogram monitoring of burst-suppression.

We previously reported that processed EEG underestimated the amount of burst suppression compared to off-line visual analysis. We performed a follow-up study to evaluate the reasons for the discordance. Forty-five patients were monitored intraoperatively with processed EEG. A computer algorithm was used to convert the SedLine® (machine)-generated burst suppression ratio into a raw duration of burst suppression. The reference standard was a precise off-line measurement by two neurologists. We measured other potential variables that may affect machine accuracy such as age, surgery position, and EEG artifacts. Overall, the median duration of bust suppression for all study subjects was 15.4 min (Inter-quartile Range [IQR] = 1.0-20.1) for the machine vs. 16.1 min (IQR = 0.3-19.7) for the neurologists' assessment; the 95% limits of agreement fall within - 4.86 to 5.04 s for individual 30-s epochs. EEG artifacts did not affect the concordance between the two methods. For patients in prone surgical position, the machine estimates had significantly lower overall sensitivity (0.86 vs. 0.97; p = 0.038) and significantly wider limits of agreement ([- 4.24, 3.82] seconds vs. [- 1.36, 1.13] seconds, p = 0.001) than patients in supine position. Machine readings for younger patients (age < 65 years) had higher sensitivity (0.96 vs 0.92; p = 0.021) and specificity (0.99 vs 0.88; p = 0.007) for older patients. The duration of burst suppression estimated by the machine generally had good agreement compared with neurologists' estimation using a more precise off-line measurement. Factors that affected the concordance included patient age and position during surgery, but not EEG artifacts.

Burst-suppression ratio underestimates absolute duration of electroencephalogram suppression compared with visual analysis of intraoperative electroencephalogram.

BACKGROUND: Machine-generated indices based on quantitative electroencephalography (EEG), such as the patient state index (PSI™) and burst-suppression ratio (BSR), are increasingly being used to monitor intraoperative depth of anaesthesia in the endeavour to improve postoperative neurological outcomes, such as postoperative delirium (POD). However, the accuracy of the BSR compared with direct visualization of the EEG trace with regard to the prediction of POD has not been evaluated previously. METHODS: Forty-one consecutive patients undergoing non-cardiac, non-intracranial surgery with general anaesthesia wore a SedLine ® monitor during surgery and were assessed after surgery for the presence of delirium with the Confusion Assessment Method. The intraoperative EEG was scanned for absolute minutes of EEG suppression and correlated with the incidence of POD. The BSR and PSI™ were compared between patients with and without POD. RESULTS: Visual analysis of the EEG by neurologists and the SedLine ® -generated BSR provided a significantly different distribution of estimated minutes of EEG suppression ( P =0.037). The Sedline ® system markedly underestimated the amount of EEG suppression. The number of minutes of suppression assessed by visual analysis of the EEG was significantly associated with POD ( P =0.039), whereas the minutes based on the BSR generated by SedLine ® were not associated with POD ( P =0.275). CONCLUSIONS: Our findings suggest that SedLine ® (machine)-generated indices might underestimate the minutes of EEG suppression, thereby reducing the sensitivity for detecting patients at risk for POD. Thus, the monitoring of machine-generated BSR and PSI™ might benefit from the addition of a visual tracing of the EEG to achieve a more accurate and real-time guidance of anaesthesia depth monitoring and the ultimate goal, to reduce the risk of POD.

Impact of intraoperative hypotension and blood pressure fluctuations on early postoperative delirium after non-cardiac surgery.

INTRODUCTION: Postoperative delirium is common in older patients. Despite its prognostic significance, the pathophysiology is incompletely understood. Although many risk factors have been identified, no reversible factors, particularly ones potentially modifiable by anaesthetic management, have been identified. The goal of this prospective cohort study was to investigate whether intraoperative hypotension was associated with postoperative delirium in older patients undergoing major non-cardiac surgery. METHODS: Study subjects were patients >65 years of age, undergoing major non-cardiac surgery, who were enrolled in an ongoing prospective observational study of the pathophysiology of postoperative delirium. Intraoperative blood pressure was measured and predefined criteria were used to define hypotension. Delirium was measured by the Confusion Assessment Method on the first two postoperative days. Data were analysed using t-tests, two-sample proportion tests and ordered logistic regression multivariable models, including correction for multiple comparisons. RESULTS: Data from 594 patients with a mean age of 73.6 years (sd 6.2) were studied. Of these 178 (30%) developed delirium on day 1 and 176 (30%) on day 2. Patients developing delirium were older, more often female, had lower preoperative cognitive scores, and underwent longer operations. Relative hypotension (decreases by 20, 30, or 40%) or absolute hypotension [mean arterial pressure (MAP)<50 mm Hg] were not significantly associated with postoperative delirium, nor was the duration of hypotension (MAP<50 mm Hg). Conversely, intraoperative blood pressure variance was significantly associated with postoperative delirium. DISCUSSION: These results showed that increased blood pressure fluctuation, not absolute or relative hypotension, was predictive of postoperative delirium.

Hedgehog signaling in the airway epithelium of patients with chronic obstructive pulmonary disease.

Genome-wide association studies have linked gene variants of the receptor patched homolog 1 (PTCH1) with chronic obstructive pulmonary disease (COPD). However, its biological role in the disease is unclear. Our objective was to determine the expression pattern and biological role of PTCH1 in the lungs of patients with COPD. Airway epithelial-specific PTCH1 protein expression and epithelial morphology were assessed in lung tissues of control and COPD patients. PTCH1 mRNA expression was measured in bronchial epithelial cells obtained from individuals with and without COPD. The effects of PTCH1 siRNA knockdown on epithelial repair and mucous expression were evaluated using human epithelial cell lines. Ptch1+/- mice were used to assess the effect of decreased PTCH1 on mucous expression and airway epithelial phenotypes. Airway epithelial-specific PTCH1 protein expression was significantly increased in subjects with COPD compared to controls, and its expression was associated with total airway epithelial cell count and thickness. PTCH1 knockdown attenuated wound closure and mucous expression in airway epithelial cell lines. Ptch1+/- mice had reduced mucous expression compared to wildtype mice following mucous induction. PTCH1 protein is up-regulated in COPD airway epithelium and may upregulate mucous expression. PTCH1 provides a novel target to reduce chronic bronchitis in COPD patients.

Protocol for the Electroencephalography Guidance of Anesthesia to Alleviate Geriatric Syndromes (ENGAGES) study: a pragmatic, randomised clinical trial.

INTRODUCTION: Postoperative delirium, arbitrarily defined as occurring within 5 days of surgery, affects up to 50% of patients older than 60 after a major operation. This geriatric syndrome is associated with longer intensive care unit and hospital stay, readmission, persistent cognitive deterioration and mortality. No effective preventive methods have been identified, but preliminary evidence suggests that EEG monitoring during general anaesthesia, by facilitating reduced anaesthetic exposure and EEG suppression, might decrease incident postoperative delirium. This study hypothesises that EEG-guidance of anaesthetic administration prevents postoperative delirium and downstream sequelae, including falls and decreased quality of life. METHODS AND ANALYSIS: This is a 1232 patient, block-randomised, double-blinded, comparative effectiveness trial. Patients older than 60, undergoing volatile agent-based general anaesthesia for major surgery, are eligible. Patients are randomised to 1 of 2 anaesthetic approaches. One group receives general anaesthesia with clinicians blinded to EEG monitoring. The other group receives EEG-guidance of anaesthetic agent administration. The outcomes of postoperative delirium (≤5 days), falls at 1 and 12 months and health-related quality of life at 1 and 12 months will be compared between groups. Postoperative delirium is assessed with the confusion assessment method, falls with ProFaNE consensus questions and quality of life with the Veteran's RAND 12-item Health Survey. The intention-to-treat principle will be followed for all analyses. Differences between groups will be presented with 95% CIs and will be considered statistically significant at a two-sided p<0.05. ETHICS AND DISSEMINATION: Electroencephalography Guidance of Anesthesia to Alleviate Geriatric Syndromes (ENGAGES) is approved by the ethics board at Washington University. Recruitment began in January 2015. Dissemination plans include presentations at scientific conferences, scientific publications, internet-based educational materials and mass media. TRIAL REGISTRATION NUMBER: NCT02241655; Pre-results.

Effects of steal-prone anatomy on intraoperative myocardial ischemia. The SPI Research Group.

OBJECTIVES: Our study objective was to determine whether the presence of steal-prone anatomy conferred an increased risk in the development of intraoperative myocardial ischemia. BACKGROUND: Coronary artery steal of collateral blood flow has been demonstrated for many vasodilators, including isoflurane, the most commonly used inhalational anesthetic agent in the United States. It has been postulated that patients with steal-prone anatomy (total occlusion of one coronary artery that is supplied distally by collateral flow from another coronary artery with a > or = 50% stenosis) may be particularly at risk for the development of intraoperative myocardial ischemia when an anesthetic with a vasodilator property is being administered. METHODS: We evaluated the risk of myocardial ischemia under isoflurane anesthesia (vs. a high dose narcotic technique using sufentanil) using continuous intraoperative electrocardiography and transesophageal echocardiography in patients with and without steal-prone anatomy undergoing coronary artery bypass graft surgery. RESULTS: Sixty-two (33%) of the 186 patients had steal-prone anatomy: in 5 (8%) the collateral-supplying vessel was > or = 50% to 69% stenosed, in 24 (39%) it was > or = 70% to 89% stenosed and in 33 (53%) it was > or = 90% stenosed. The incidence of ischemia (transesophageal echocardiography or intraoperative electrocardiography, or both) was similar in patients with and without steal-prone coronary anatomy (18 [29%] of 62 patients vs. 39 [31%] of 124 patients, p = 0.87, 95% confidence interval = -0.13 to 0.17). The incidence of intraoperative ischemia was similar in patients who received isoflurane or sufentanil anesthesia (20 [32%] of 62 patients vs. 37 [30%] of 124 patients, p = 0.87). The incidence of tachycardia and hypotension was low (increases in heart rate = 9.8%, and decreases in systolic blood pressure = 10.8% of total monitoring time during the prebypass period compared with preoperative baseline values). The incidence of adverse cardiac outcome was similar in patients with and without preoperative steal-prone coronary anatomy (4 [7%] of 62 patients vs. 14 [11%] of 124 patients, p = 0.53). CONCLUSIONS: These findings demonstrate that under strict hemodynamic control the presence of steal-prone anatomy does not confer an increased risk in the development of intraoperative myocardial ischemia.

Relationship of the proinflammatory cytokines to myocardial ischemia and dysfunction after uncomplicated coronary revascularization.

The proinflammatory cytokines have been implicated in mediating myocardial dysfunction associated with myocardial infarction, severe congestive heart failure, and sepsis. We tested the hypothesis that cytokine levels are elevated after uncomplicated coronary artery bypass grafting and associated with episodes of postoperative myocardial ischemia and dysfunction. Coronary artery bypass grafting was performed under general anesthesia with moderate systemic hypothermia and cold-blood potassium cardioplegic solution. Tumor necrosis factor-alpha and interleukin-6 levels were determined by bioassays, and interleukin-8 levels were measured by a sandwich enzyme-linked immunosorbent assay. Myocardial function and ischemic episodes were assessed by intraoperative transesophageal echocardiography and perioperative 12-channel Holter monitoring. A total of 22 patients were studied, with no deaths or complications. Arterial tumor necrosis factor-alpha rose in a bimodal distribution, peaking at 2 and 18 to 24 hours after the operation (at 20.2 +/- 6.4 pg/ml, [mean +/- standard error of the mean]) and 5.8 +/- 1.6 pg/ml, respectively; before cardiopulmonary bypass: 0.90 +/- 0.20 pg/ml, p < 0.001 for both peaks) then progressively declined to levels before bypass. Arterial interleukin-6 was maximally elevated immediately on termination of cardiopulmonary bypass and peaked again 12 to 18 hours after cardiopulmonary bypass (at 7520 +/- 2439 pg/ml and 6216 +/- 1928 pg/ml, respectively; before bypass: 746 +/- 187 pg/ml, p < 0.0001 for both peaks). Arterial interleukin-8 levels were more variable but followed a similar pattern, peaking in the early period after cardiopulmonary bypass and again at 16 to 18 hours after the operation (at 4110 +/- 1403 pg/ml and 1760 +/- 1145 pg/ml, respectively; before bypass: 461 +/- 158, p < 0.05 for both peaks). By multivariate analysis, the aortic crossclamp time was independently predictive of postoperative cytokine levels. Left ventricular wall motion abnormalities were associated with both interleukin-6 and interleukin-8 levels, worsening scores being associated with increasing levels (for interleukin-6, p = 0.003; for interleukin-8, p = 0.05). Postoperative myocardial ischemic episodes were associated with interleukin-6 levels, six of seven (85%) patients with episodes of myocardial ischemia after a peak in interleukin-6 concentrations (p < 0.01). We conclude that proinflammatory cytokines are elevated after uncomplicated coronary revascularization and may contribute to postoperative myocardial ischemia and segmental wall motion abnormalities.

Predicting adverse postoperative outcomes in patients aged 80 years or older.

OBJECTIVE: The identification of reversible factors that are associated with postoperative morbidity in geriatric surgical patients is critical to improving perioperative outcomes in such patients. Our study aimed to compare the relative importance of intraoperative versus preoperative factors in predicting adverse postoperative outcomes in geriatric patients. DESIGN: Retrospective cohort study of consecutive patients undergoing noncardiac surgery in 1995. SETTING: Two University of California, San Francisco, teaching hospitals--Moffitt/Long and Mount Zion medical centers. PARTICIPANTS: All men and women 80 years of age or older undergoing noncardiac surgery. MEASUREMENTS: Medical records of all patients were reviewed to measure predefined pre- and intraoperative risk factors and postoperative outcomes. Predictors of postoperative outcomes were identified by multivariate logistic regression analyses. RESULTS: Three hundred sixty-seven patients were studied. The most prevalent preoperative risk factors were a history of hypertension and coronary artery, pulmonary, and neurologic diseases. Postoperative in-hospital mortality rate was 4.6%, and 25% of patients developed adverse postoperative outcomes, of which neurological and cardiovascular complications were the leading causes of morbidity (15% and 12%, respectively). By multivariate logistic regression, a history of neurological disease (odds ratio [OR] 4.0, 95% confidence interval [CI] 2.3 - 6.9, P = .0001), congestive heart failure (OR 2.7, 95% CI 1.4 - 5.3, P = .004), and a history of arrhythmia (OR 2.3, 95% CI 1.2 - 4.3, P = .01) increased the odds of adverse postoperative events. The only intraoperative event shown to be predictive of postoperative complications was the use of vasoactive agents (OR 8.0, 95% CI 1.6 - 40.5, P = .009). CONCLUSIONS: In this group of geriatric surgical patients, the overall postoperative in-hospital mortality rate was 4.6%, and 25% of the patients developed adverse postoperative outcomes involving either the neurological, cardiovascular, or pulmonary systems. Intraoperative events appeared to be less important than preoperative comorbidities in predicting adverse postoperative outcomes.

Relative importance of preoperative health status versus intraoperative factors in predicting postoperative adverse outcomes in geriatric surgical patients.

OBJECTIVES: To determine the prevalence and predictors of adverse postoperative outcomes in older surgical patients undergoing noncardiac surgery. DESIGN: Prospective cohort study of consecutive patients undergoing noncardiac surgery in 1997. SETTING: A medical school-affiliated teaching community hospital. PARTICIPANTS: Patients age 70 and older undergoing noncardiac surgery. Patients presenting for surgery requiring only local anesthesia or monitored anesthesia care were excluded. MEASUREMENTS: Potential pre- and intra-operative risk factors were measured and evaluated for their association with the occurrence of predefined in-hospital postoperative adverse outcomes. Univariate predictors of postoperative outcomes were first measured using the chi-square or Fisher's exact tests followed by multivariate logistic regression. Odds ratios (OR) with 95% confidence interval (CI), and two-sided P-values were reported. RESULTS: Five hundred forty-four consecutive patients were studied. Overall, 21% of patients developed one or more postoperative adverse outcomes and 3.7% died during the in-hospital postoperative period. Of all the adverse outcomes, cardiovascular complications (10.3%) were the leading cause of morbidity, followed by neurological (7.7%) and pulmonary complications (5.5%). By multivariate logistic regression analysis, American Society of Anesthesiologists (ASA) classification (OR = 2.7, CI = 1.6-4.4), emergency surgery (OR = 2.0, CI = 1.1-3.4), and intraoperative tachycardia (OR = 3.8, CI = 1.9-7.6) were the most important predictors of postoperative adverse outcomes. Of all the preoperative physical symptoms and signs, decreased functional status (OR = 3.0, CI = 1.4-6.4) and clinical signs of congestive heart failure (OR = 2.1, CI = 1.1-5.1) were the two most important predictors of postoperative adverse neurological and cardiac outcomes, respectively. The median hospital stay was 4 days. The patients who developed postoperative adverse outcomes had significantly longer median hospital stays (9 days) than those without complications (3 days), (P < .0001). CONCLUSION: Our study demonstrates that the postoperative mortality rate in geriatric surgical patients undergoing noncardiac surgery is low. Despite the prevalence of preoperative chronic medical conditions, most patients do well postoperatively. The ASA classification (a reflection of the severity of preoperative comorbidities), emergency surgery, and intraoperative tachycardia increase the odds of developing any postoperative adverse events. Future studies aimed at modifying some of the potentially reversible risk factors, such as preoperative heart function and intraoperative heart rate are warranted.

IL-22-producing CD4+ cells are depleted in actively inflamed colitis tissue.

T helper type (Th17) cytokines such as interleukin (IL)-17A and IL-22 are important in maintaining mucosal barrier function and may be important in the pathogenesis of inflammatory bowel diseases (IBDs). Here, we analyzed cells from the colon of IBD patients and show that Crohn's disease (CD) patients had significantly elevated numbers of IL-17+, CD4+ cells compared with healthy controls and ulcerative colitis (UC) patients, but these numbers did not vary based on the inflammatory status of the mucosa. By contrast, UC patients had significantly reduced numbers of IL-22+ cells in actively inflamed tissues compared with both normal tissue and healthy controls. There was a selective increase in mono-IL-17-producing cells from the mucosa of UC patients with active inflammation together with increased expression of transforming growth factor (TGF)-ß and c-Maf. Increasing concentrations of TGF-ß in lamina propria mononuclear cell cultures significantly depleted Th22 cells, whereas anti-TGF-ß antibodies increased IL-22 production. When mucosal microbiota was examined, depletion of Th22 cells in actively inflamed tissue was associated with reduced populations of Clostridiales and increased populations of Proteobacteria. These results suggest that increased TGF-ß during active inflammation in UC may lead to the loss of Th22 cells in the human intestinal mucosa.

Nitrous oxide does not change the incidence of postoperative delirium or cognitive decline in elderly surgical patients.

BACKGROUND: Postoperative delirium and cognitive decline are common in elderly surgical patients after non-cardiac surgery. Despite this prevalence and clinical importance, no specific aetiological factor has been identified for postoperative delirium and cognitive decline. In experimental setting in a rat model, nitrous oxide (N(2)O) produces neurotoxic effect at high concentrations and in an age-dependent manner. Whether this neurotoxic response may be observed clinically has not been previously determined. We hypothesized that in the elderly patients undergoing non-cardiac surgery, exposure to N(2)O resulted in an increased incidence of postoperative delirium than would be expected for patients not receiving N(2)O. METHODS: Patients who were >or=65 yr of age, undergoing non-cardiac surgery and requiring general anaesthesia were randomized to receive an inhalational agent and either N(2)O with oxygen or oxygen alone. A structured interview was conducted before operation and for the first two postoperative days to determine the presence of delirium using the Confusion Assessment Method. RESULTS: A total of 228 patients were studied with a mean (range) age of 73.9 (65-95) yr. After operation, 43.8% of patients developed delirium. By multivariate logistic regression, age [odds ratio (OR) 1.07; 95% confidence interval (CI) 1.02-1.26], dependence on performing one or more independent activities of daily living (OR 1.54; 95% CI 1.01-2.35), use of patient-controlled analgesia for postoperative pain control (OR 3.75; 95% CI 1.27-11.01) and postoperative use of benzodiazepine (OR 2.29; 95% CI 1.21-4.36) were independently associated with an increased risk for postoperative delirium. In contrast, the use of N(2)O had no association with postoperative delirium. CONCLUSIONS: Exposure to N(2)O resulted in an equal incidence of postoperative delirium when compared with no exposure to N(2)O.

Pilot clinical trial of gabapentin to decrease postoperative delirium in older patients.

In this randomized pilot clinical trial, the authors tested the hypothesis that using gabapentin as an add-on agent in the treatment of postoperative pain reduces the occurrence of postoperative delirium. Postoperative delirium occurred in 5/12 patients (42%) who received placebo vs 0/9 patients who received gabapentin, p = 0.045. The reduction in delirium appears to be secondary to the opioid-sparing effect of gabapentin.

Clinical evidence of myocardial stunning in patients undergoing CABG surgery.

Although patients who have undergone coronary artery bypass graft (CABG) surgery frequently present with symptoms suggesting that myocardial stunning has occurred, measurements of regional myocardial function and perfusion are difficult in clinical settings. Several studies have used left ventricular function indices (i.e., cardiac index, left ventricular stroke work index, ejection fraction) to assess myocardial stunning immediately following CABG surgery. These changes in ventricular function have been found to be reversible and the clinical data are consistent with the occurrence of myocardial stunning. Myocardial metabolism is also reportedly depressed following CABG surgery. Decreases in myocardial oxygen extraction, consumption, and lactate utilization all point to the presence of myocardial stunning, as do abnormalities in regional wall-motion and electrocardiographic changes (i.e., transient Q waves) described in patients who have undergone CABG surgery. New approaches to differentiating viable from nonviable myocardial tissue will likely include stress echocardiography using new stress agents, ultrasound contrast agents, and high frequency ultrasound.

Dissociation between haemodynamics and sympathetic activation during anaesthetic induction with desfluranes.

PURPOSE: To compare the simultaneous haemodynamic effects, sympathetic activation and cardiac risks associated with desflurane used in a balanced technique, with those of isoflurane anaesthesia. METHODS: A prospective, randomized, open label study was conducted at a University medical centre. Forty patients undergoing major non-cardiac surgery were randomized to receive either desflurane or isoflurane as the primary anaesthetic agent. After premedication, fentanyl and thiopentone were administered i.v.. Anaesthesia was increased up to 1.0 MACET in O2 via controlled mask ventilation and maintained at 1.0 MAC before tracheal intubation. Maintenance consisted of N2O, O2 and desflurane or isoflurane for 10 min. During the study, HR and arterial BP were continuously measured, as were ECG ST-segments and ventricular dysrhythmias using a 3-channel Holter ECG recorder. Left ventricular global and regional function were measured using precordial echocardiography. Serial plasma catecholamine concentrations were measured. RESULTS: For both groups, HR was maintained without increases over baseline values while systolic BP showed a progressive decrease during induction. Use of beta blockade during induction was higher in the desflurane (7/20 = 35%) than in the isoflurane group (1/20 = 5%), P = 0.04. The plasma norepinephrine concentrations progressively increased in the desflurane group but not in the isoflurane group. Four patients in the desflurane and three in the isoflurane group developed transient worsening of regional function but no change in mean left ventricular ejection fraction area and no ECG ischaemia occurred during anaesthetic induction. CONCLUSIONS: Desflurane differs from isoflurane in that sympathetic stimulation persisted despite blunting of potential hyperdynamic haemodynamic responses by narcotic and beta blockade. However, this sympathetic activation did not appear to increase cardiac risks.

Left ventricular end-systolic cavity obliteration as an estimate of intraoperative hypovolemia.

BACKGROUND: Transesophageal echocardiography is increasingly used intraoperatively as a monitor of ventricular function and volume. Although obliteration of the left ventricular (LV) cavity at end-systole is interpreted as indicative of intraoperative hypovolemia, this relation has not been demonstrated directly. METHODS: We continuously monitored the LV short axis by using transesophageal echocardiography and determined the relation between acute changes in LV area and hemodynamic variables in 139 patients undergoing elective coronary artery bypass graft surgery. The end-diastolic areas (EDA) and end-systolic areas were calculated during the control state (after anesthetic induction) and during LV end-systolic cavity obliteration. RESULTS: Thirty-nine of 139 patients had episodes of LV cavity obliteration. Mean LV end-systolic area decreased significantly from the control to obliterated state (7.29 +/- 2.56 to 4.00 +/- 1.46 cm2, P = 0.0001). The corresponding mean LV EDA also significantly decreased from the control to obliterated state (18.18 +/- 4.36 to 12.92 +/- 3.74 cm2, P = 0.0001). Mean ejection fraction area increased from 0.609 +/- 0.095 (control) to 0.692 +/- 0.083 (obliteration) (P < 0.0001). Of these 39 episodes, 31 (80%) were associated with a greater than 10% decrease in EDA relative to the initial value after induction of anesthesia and tracheal intubation; 4 (10%) with increases in ejection fraction area only; and an additional 4 (10%) with no substantial change in either the EDA or ejection fraction area. Overall, LV cavity obliteration was not associated with hemodynamic changes. CONCLUSIONS: Our study demonstrates that LV cavity obliteration is rarely preceded by any acute alteration in hemodynamic parameters. Although end-systolic cavity obliteration detected by intraoperative transesophageal echocardiography is frequently associated with decreases in EDA, not every instance of end-systolic cavity obliteration is indicative of decreased left ventricular filling.

Postoperative myocardial ischemia in patients undergoing coronary artery bypass graft surgery. S.P.I. Research Group.

Cardiac morbidity and mortality after coronary artery bypass graft (CABG) surgery continue to be significant problems. To determine the prevalence, characteristics, and prognostic importance of postoperative myocardial ischemia after CABG surgery, the authors monitored 50 patients continuously for 10 perioperative days with the use of two-lead electrocardiography (ECG). ECG changes consistent with ischemia were defined as a reversible ST depression of 1 mm or greater or an elevation of 2 mm or greater from baseline, lasting at least 1 min. Baseline was adjusted for positional changes and temporal drift. All episodes were verified, with the use of the ECG monitor printout (ECG complexes), by two independent blinded investigators. Clinical care was not controlled by study protocol, and clinicians were unaware of the research data collected. Twenty-six of 50 patients (52%) had 207 episodes of perioperative ischemia (3,409 ischemic minutes). Postoperatively, ischemia developed in 48% of patients, compared with 12% preoperatively and 10% intraoperatively before bypass. Postoperative ischemia was most common in the early period (postoperative days [PODs] 0-2; 38% of patients), peaking during the first 2 h after revascularization, and less common during the late postoperative period (PODs 3-7; 24% of patients). Almost all (120 of 122; 98%) postoperative episodes (after tracheal extubation) were asymptomatic: only 9 of 70 (13%) early episodes were detected by clinical ECG monitoring. Postoperative ischemia did not appear to be related to acute changes in myocardial oxygen demand: only 39% of the postoperative episodes were preceded by a greater than 20% increase in heart rate. However, tachycardia persisted throughout the postoperative week (22-33% of all heart rates greater than 100 beats per min), and patients with postoperative ischemia (POD 0) more frequently had tachycardia (median 43% vs. 12% of the time; P less than 0.01). Five adverse cardiac outcomes occurred on the day of surgery; all five were preceded by postoperative ischemia, three by intraoperative ischemia before bypass, and none by preoperative ischemia. Patients with late postoperative ischemia did not have an adverse cardiac outcome. The authors conclude the following: 1) ischemia is more prevalent postoperatively than preoperatively or intraoperatively before bypass; 2) the incidence of postoperative ischemia peaks shortly after revascularization, during which time it is symptomatically silent, difficult to detect, and related to adverse cardiac outcome; 3) late postoperative ischemia also is silent, but it is less prevalent and not associated with in-hospital adverse cardiac outcome; and 4) a relationship between ischemia and persistently elevated postoperative heart rate may exist and warrants additional investigation.

The prevalence and predictors of the use of alternative medicine in presurgical patients in five California hospitals.

UNLABELLED: We measured the prevalence and predictors of the use of alternative medicine supplements in surgical patients by way of a self-administered questionnaire in consecutive patients > or = 18 yr old awaiting elective noncardiac surgery at five San Francisco Bay Area Hospitals. A total of 2560 patients completed the study survey (60% response rate). Of these patients, 39.2% admitted to using some form of alternative medicine supplements, of which herbal medicine was the most common type (67.6%). Of those who admitted to taking alternative medicine supplements, 44.4% did not consult with their primary physicians, and 56.4% did not inform the anesthesiologists before surgery regarding their use of these products; 53% of the patients ceased the use of these products before surgery. Multivariate logistic regression analysis revealed the following variables to be associated with the preoperative use of herbal medicine: female sex (odds radio [OR] 1.42, confidence interval [CI] 1.17-1.72), age 35-49 yr (OR 1.25, CI 1.02-1.53), higher income levels (OR 1.85, CI 1.50-2.27), Caucasian race (OR 1.34, CI 1.07-1.67), higher level of education (OR 1.35, CI 1.10-1.65), problems with sleep (OR 1.32, CI 1.05-1.66), problems with joints or back (OR 1.27, CI 1.04-1.56), allergies (OR 1.48, CI 1.21-1.82), problems with addiction (OR 1.90, CI 1.25-2.89), and a history of general surgery (OR 1.25, CI 1.03-1.52). In contrast, diabetes mellitus (OR 0.55, CI 0.36-0.86) and the use of antithrombotic medications (OR 0.57, CI 0.38-0.87) were associated with decreased odds of the use of herbal medicines. We concluded that the use of alternative medicine supplements by surgical patients is prevalent. Documentation of the use of these products is critical to determine the potential of drug or anesthetic interactions in the perioperative period. IMPLICATIONS: The use of alternative medicine supplements by presurgical patients is prevalent. Documentation of the use of these products is critical to determine the potential of drug or anesthetic interactions in the perioperative period.

Transesophageal echocardiography in myocardial revascularization: I. Accuracy of intraoperative real-time interpretation.

Transesophageal echocardiography (TEE) is increasingly used intraoperatively as a monitor of ventricular function and volume. Despite its increasing use, whether data from TEE monitoring can be interpreted accurately on-line in real-time is unknown. We studied the performance of five community-based, full-time cardiac anesthesiologists during 75 surgical procedures in which biplane TEE monitoring was used. Every 10 min intraoperatively, each anesthesiologist evaluated the video cine loop display of echocardiographic images to provide a real-time visual estimate of left ventricular ejection fraction area (EFA) and left ventricular filling at the level of the short axis and to assess regional wall-motion of the short axis and transgastric longitudinal views using a predefined scoring system. The same video images were analyzed quantitatively off-line by two blinded investigators. Intraoperative real-time estimates of EFA correlated moderately with off-line quantification (r = 0.8, P = 0.0001). Of the 662 cine loops analyzed by both off-line and real-time techniques, 386 (55%) were within +/-5% of each other, 495 (75%) were within +/-10% of each other, 561 (85%) were within +/-15% of each other, and 617 (93%) were within +/-20% of each other. The overall sensitivity and specificity of real-time echocardiographic ischemia detection were both 76%. However, there was individual variation among the five anesthesiologists. Recognition of normal and severe regional wall-motion abnormality, such as akinesis, had more concordance between real-time and off-line analysis, 93% and 79%, respectively, than recognition of mild regional wall-motion abnormalities. Anesthesiologists can estimate EFA in real-time to within +/-10% of off-line values in 75% of all cases. Real-time identification of normal regional function is more accurate than identification of abnormal function, i.e., there is variability in quantifying the severity of regional dysfunction.