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Objective: To investigate the use and impact of transesophageal echocardiography (TEE) during noncardiac surgery., Design: Retrospective study., Setting: A university teaching hospital., Participants and Interventions: The medical records and the videotapes of 123 intraoperative TEE examinations were reviewed., Measurements and Main Results: TEE was used for non-consultative indications in 68 patients and in consultation in 55 patients. Information that would not have been detected intraoperatively by other means included intracardiac defects, valvular and aortic pathology, the presence or absence of ventricular dysfunction or intracardiac thrombi, and embolization during surgery. Findings during the initial TEE examination and the TEE evaluation of intraoperative events resulted in a major impact on patient management in 15% of patients. The majority of patients in whom TEE had any impact (the sum of major, minor, and limited impact groups) were classified as American Society of Anesthesiologists (ASA) class 3 or 4. Patients in whom TEE had any impact were significantly older than patients in whom TEE had no impact (66.5 +/- 13.4 years v 58.1 +/- 16.2 years; p < 0.05). No patient experienced a complication related to intraoperative TEE., Conclusion: It appears that TEE in patients undergoing noncardiac surgery is efficacious in rapidly disclosing new findings and information during periods of hemodynamic instability. It may have a significant impact on intraoperative patient management and may be beneficial in patients older than 66 years of age.

Background: Intraoperative blood pressure lability may be related to risk factors, hypovolemia, light anesthesia, and morbid outcomes, but the measurements of lability in previous studies have been limited by imprecise and infrequent data collection methods. Computerized intraoperative data acquisition systems have provided an opportunity to readdress the issue of intraoperative blood pressure lability with more abundant and precise data. This study sought to derive and validate an algorithm (expert system) to measure mean arterial pressure (MAP) lability., Methods: Two hundred thirty-nine computerized anesthesis records were reviewed retrospectively. Three anesthesiologists separately rated MAP as very stable, average, or very labile. The parameters of a computer algorithm that measured the change of median MAP between consecutive 2-min epochs were optimized to achieve the best possible agreement among the anesthesiologists. The algorithm was then validated on 229 additional anesthesia records., Results: The proportion of consecutive 2-min epochs in which the absolute value of the fractional change of median MAP exceeded 0.06 (i.e., 6%) correlated strongly with the anesthesiologists' ratings (r = 0.78; P < 0.0001). The optimal sensitivity and specificity of the algorithm for detecting MAP lability were 98% and 59%, respectively., Conclusions: One potential application of expert systems to anesthesia practice is a "smart alarm" to detect blood pressure lability. It may also provide a better tool to assess the relation between lability and outcome than has been available previously.

Objective: A test was developed that is based on intraoperative findings to evaluate knowledge of intraoperative echocardiography. This study examines the performance of attending anesthesiologists and residents at various levels of training in order to validate the test's ability to measure physician competence in intraoperative echocardiographic diagnosis., Design: This study was a prospective evaluation of a test of competence in transesophageal echocardiography., Setting: Two university medical centers., Participants: Volunteer anesthesia faculty and residents., Interventions: The participants took an echocardiographic examination that consisted of 34 "K"-type multiple-choice questions and a 45-second video-loop sequence for each question. The video sequences were chosen for their high quality and unambiguous representation of both normal and pathologic images obtained by transverse transesophageal echocardiographic imaging. The questions were written by experienced echocardiographers. The test was administered to 25 individuals at two academic institutions: 11 residents with minimal transesophageal echocardiography exposure and 14 faculty who were relatively experienced with transesophageal echocardiography. All of the residents repeated the examination at the end of their third clinical anesthesia year, which included transesophageal echocardiography training. The differences between the groups' scores were analyzed using the Kruskal-Wallis test and Wilcoxon's rank-sum test. To correct for the multiple comparisons, p < 0.025 was deemed significant. MEASUREMENTS AND MAIN RESULTS. Before their transesophageal echocardiography training, the residents scored significantly lower than the faculty (p < 0.002). After 1 year of training, their scores significantly increased (p = 0.021), and their scores were not significantly different from the faculty level (p = 0.052)., Conclusions: Test performance differed according to level of experience. This suggests that the test is a valid measure of intraoperative transesophageal echocardiography competence.

Background: Pulse oximeters have been reported to fail to record data in 1.12-2.50% of cases in which anesthesia records were handwritten. There is reason to believe that these may be underestimates. Computerized anesthesia records may provide insight into the true incidence of pulse oximetry data failures and factors that are associated with such failures., Methods: The current study reviewed case files of 9,203 computerized anesthesia records. Pulse oximetry data failure was defined as the presence of at least one continuous gap in data > or = 10 min in duration in a case. A multivariate logistic regression model was used to identify predictors of pulse oximetry data failure, and a modified case-control method was used to determine whether extremes of blood pressure and hypothermia during the procedure were associated with pulse oximetry data failure., Results: The overall incidence of cases that had at least one continuous gap of > or = 10 min in pulse oximetry data was 9.18%. The independent preoperative predictors of pulse oximetry data failure were ASA physical status 3,4, or 5 and orthopedic, vascular, and cardiac surgery. Intraoperative hypothermia, hypotension, hypertension, and duration of procedure were also independent risk factors for pulse oximetry data failure., Conclusions: Pulse oximetry data failure rates based on review of computerized records were markedly greater than those previously reported. Physical status, type of surgery, and intraoperative variables were risk factors for pulse oximetry data failure. Regulations and expectations regarding pulse oximetry monitoring should reflect the limitations of the technology.

Intraoperative decisions are often based on interpretation of results from transesophageal echocardiography (TEE). One such area is the intraoperative evaluation of atheromatous disease of the thoracic aorta and subsequent classification or grading. These grading schemes are predictive of stroke after cardiac surgery. Since intraoperative strategies may be modified based on this TEE aortic atheroma grading, assessment of the interobserver variability of TEE findings between observers is essential. Forty TEE videotape segments imaging three portions of the thoracic aorta (ascending, arch, descending) were selected from 189 reports of a larger cohort. Three independent, blinded observers, experienced in TEE, evaluated these examinations for atheroma severity. If a TEE segment had insufficient data, "uninterpretable" was recorded. Weighted kappa coefficients of agreement were calculated on the three data sets. Mean weighted kappa coefficients for the three observers A, B, and C were 0.69, 0.74, and 0.72, for the ascending, arch, and descending aorta segments, respectively, representing excellent agreement. We have demonstrated uniformly high agreement for interpretation of TEE, which indicates the excellent reproducibility of TEE grading and stratification of aortic atheroma. Reproducibility within and across specialties and institutions is essential for widespread application of TEE for evaluation of the thoracic aorta.

Cisatracurium (Nimbex) is an intermediate-acting benzylisoquinolinium neuromuscular blocker that is one of the stereoisomers of atracurium. It causes no clinically significant cardiovascular side effects or histamine release in doses up to 8 x ED95 in healthy patients. Seventy patients undergoing elective myocardial revascularization consented to participate in an Institutional Review Board approved pilot study (10 patients) and an open-label, randomized, controlled trial comparing the hemodynamic effects of cisatracurium with vecuronium (60 patients) at two centers. The patients were anesthetized using 100% oxygen, fentanyl, and midazolam, and tracheal intubation was facilitated with succinylcholine. At least 5 min after tracheal intubation, baseline hemodynamic measurements were obtained. The patients received 0.10 mg/kg of cisatracurium (2 x ED95) or 0.10 mg/kg of vercuronium (2 x ED90) as follows: cisatracurium over 60 s (Pilot Group A, n = 5); cisatracurium over 30 s (Pilot Group B, n = 5); cisatracurium over 5-10 s (Group C, n = 30); or vecuronium over 5-10 s (Group D, n = 30). The hemodynamic measurements were repeated at 2, 5, and 10 min after cisatracurium or vecuronium injection. There were no episodes of cutaneous flushing. One patient was hypotensive before and after cisatracurium administration, and was excluded from analysis. Otherwise, there were no episodes of hypotension requiring therapy in any patient after cisatracurium. Fifteen patients overall were excluded from the analysis for one or more of the following: light anesthesia, treatment for hypotension < 10 min prior to baseline, or equipment difficulties.(ABSTRACT TRUNCATED AT 250 WORDS)

Atherosclerosis of the ascending aorta may be associated with a higher perioperative stroke risk in cardiac surgery. This study investigated the use of biplane transesophageal echocardiography (TEE) scanning of the entire thoracic aorta to predict the presence of plaque in the ascending aorta. Eighty-one patients (57 male, 24 female; aged 32-88 yr, mean age 64 yr) scheduled for elective cardiac surgery participated in an institutional review board-approved protocol. A comprehensive examination of the entire thoracic aorta in both the longitudinal and transverse planes was performed. After pericardiotomy, a sterilely draped 7-MHz probe was used to scan the entire ascending aorta in both long and short axis views. In both echocardiographic examinations, the presence and location of protruding plaques and intimal thickening > 3 mm were recorded. Using epiaortic (EPI) scanning as the "gold standard," the sensitivity, specificity, positive predictive value, and negative predictive value of TEE for detecting ascending aortic atherosclerosis were calculated. Fourteen (17%) of the 81 patients had significant atherosclerotic disease of the ascending aorta as diagnosed by EPI echocardiography. The sensitivity of TEE was 100%, the specificity was 60%, the positive predictive value was 34%, and the negative predictive value was 100%. These data show that, if the complete biplane TEE examination is negative for plaque, it is highly unlikely that there is significant plaque in the ascending aorta. If the TEE examination is positive for plaque, there is a 34% chance that there is significant disease of the ascending aorta, and EPI scanning should be considered. Thus, TEE is a very sensitive but only mildly specific method of determining whether ascending aortic atherosclerosis is present.

An early transesophageal echocardiography (TEE) study reported that there was high inter- and intraobserver variability in measurements of wall thickening (WT). This study reevaluated TEE for the measurement of WT in the transverse plane and, for the first time, evaluated it in the longitudinal plane. Ten patients were studied with a biplane TEE probe inserted and positioned to obtain a transverse short-axis (SA) view of the left ventricle at the midpapillary muscle level. A longitudinal transgastric long-axis (LA) view of the left ventricle was then obtained. This measurement sequence was performed four times in each patient. Off-line analysis was performed independently by two observers. In each tomographic cut of the ventricle, four locations for measurement were defined. WT was measured in three consecutive beats, and the results averaged (WT1). The observers repeated the measurements (WT2) 2 wk later, and the intra- and interobserver differences (mm) were calculated. Average differences for the intraobserver comparisons of wall thickening were small (0.08-0.24 mm), but the high standard deviations (1.17-2.44 mm) suggest significant variability between individual measurements. Thus it appears that measurements of wall thickening with small mean intraobserver bias may be possible, but to offset the potential for variability, multiple measurements are necessary. Also, careful standardization of location and edge definition is important to limit interobserver variability.

Anesthetic agents may significantly alter the patient's blood pressure, and thus affect the intraoperative assessment of mitral regurgitation. This study examined the impact of an increase in afterload on a variety of parameters thought to reflect the severity of mitral regurgitation, and related them to changes in hemodynamic parameters. Twenty-four patients with mitral regurgitation undergoing cardiac surgery were studied. Following the induction of anesthesia, color-flow mapping of the entire left atrium was performed, and pulmonary vein flow was then measured. Phenylephrine was administered to increase the patients' blood pressures to their preoperative values, and the assessment was repeated. Regurgitant jet area increased 56% (482 +/- 405 v 750 +/- 440 mm2 P < 0.001), and there were significant reductions in systolic pulmonary venous velocity (0.33 +/- 0.17 v 0.18 +/- .31 m/s P < .01) with increases in diastolic flow (0.43 +/- 12 v 0.58 +/- 0.18 m/s P < .001). These changes in pulmonary venous flow were not related to the changes in the driving force across the incompetent mitral valve. Also, an additional six patients developed systolic flow reversal after phenylephrine administration. Intraoperative hemodynamic variations can significantly alter the apparent severity of mitral regurgitation, and this factor must be considered during decision making.

We assessed the ability of transesophageal echocardiography (TEE) to examine the entire length of the ascending aorta. TEE-derived data were compared with anatomic measurements and epiaortic scanning. There were 27 patients (19 male, 8 female; aged 67 +/- 12 yr) studied during cardiac surgery. The surgeon measured the distance between the aortic anulus near the right coronary artery to the origin of the innominate artery (AV-->IN) and to the level of the aortic cannulation site (AV-->C). Independently, the ascending aorta was imaged by biplane TEE and the maximum length of aorta visualized was measured (TEE-MAX). Additionally, TEE was used to detect atheromas in the aorta and to visualize the aortic cannula. Epiaortic scanning was also performed in 14 patients. Direct measurement of the ascending aorta revealed a length of 8.9 +/- 1.3 cm (mean +/- SD) and the TEE-MAX was 7.4 +/- 1.1 cm. The range of the difference between the two measurements was 0.2-4.5 cm. The aortic cannula was visualized only in 1 of 27 patients, and severe atherosclerotic plaques (> 3 mm thick), not seen on TEE, were detected in five patients with epiaortic scanning. As much as 42% (4.5 cm of 10.7 cm) of the length of the ascending aorta was not visualized and potentially embolic plaques were not imaged by TEE. These findings suggest that even biplane TEE may have limited use in the precannulation assessment of the aorta for plaque and the detection of distal ascending aortic pathology.

Echocardiographic techniques are useful in establishing the presumptive clinical diagnosis of paradoxical embolism. Once a clinical diagnosis of systemic embolism has been established and a potential systemic venous source for embolic material has been diagnosed, echocardiographic (and particularly transesophageal echocardiographic techniques) can readily establish the presence or absence of an intracardiac communication and can help define the potential for right to left shunting across that communication (using saline contrast techniques). Except for the rare circumstance where echocardiography has been used to actually image paradoxical embolization in progress (such as may occur during intraoperative monitoring), the technique can only show the potential for such a mechanism for systemic embolization. Because patency of the foramen ovale is a common anatomic variant (occurring in approximately 25% of subjects) and transesophageal contrast echocardiography will show at least transient right to left shunting in most patients with patent foramen ovale, a mechanistic relationship between such findings and the occurrence of a systemic embolic event cannot be immediately inferred. Clinical assessment of alternative mechanisms for systemic embolization is required to judge the likelihood that the potential for paradoxical embolization is, in fact, the cause for systemic embolism in a given patient.

Background: Intraoperative blood volume changes are difficult to monitor in pediatric patients. The authors tested the hypothesis that transesophageal echocardiography would identify changes in cardiac filling resulting from manipulations of blood volume., Methods: Eleven patients (3-15 kg) were studied following sternal closure after repair of congenital heart lesions. Transesophageal echocardiography of the midpapillary left ventricular short axis view and hemodynamics were recorded at baseline (T1), during withdrawal of blood until the systolic blood pressure decreased by 5 mmHg (T2) and 10 mmHg (T3), and after reinfusion of the blood (T4). The identical cycle of blood withdrawal and reinfusion was repeated after administration of calcium chloride (10 mg/kg; T5-T8)., Results: Manually traced transesophageal echocardiography images of the left ventricular end-diastolic area decreased from 4.64 +/- 1.50 cm2 at T1 to 4.03 +/- 1.25 cm2 at T2 to 3.78 +/- 1.35 cm2 at T3, and increased to 4.42 +/- 1.75 cm2 at T4. Nearly identical results were obtained at T5-T8. End-systolic areas significantly decreased from 1.96 +/- 0.86 cm2 at T1 to 1.52 +/- 0.73 cm2 at T2 to 1.41 +/- 0.62 cm2 at T3, and increased to 1.87 +/- 0.88 cm2 at T4. An experienced anesthesiologist-echocardiographer blinded to study events was able to identify mild reductions in blood volume (T2, T3, T6, T7) from recorded cine-loop video recordings with high sensitivity (80-95%) and specificity (80%)., Conclusions: Transesophageal echocardiography is a potentially useful monitor of cardiac filling changes in pediatric patients.

Objectives: The purpose of this study was to estimate the prevalence of potential right to left interatrial shunting and to quantify the morphologic characteristics of the fossa ovalis in adults without a prior history of stroke or systemic embolism., Background: Paradoxic embolization through a patent foramen ovale is an important cardiac mechanism for embolic stroke. Although anatomic and physiologic data obtained by transesophageal echocardiography increase the frequency of demonstration of potential cardiac sources of systemic embolism and occasionally can conclusively demonstrate the mechanism for embolic stroke, the prevalence and prognostic implications of these findings in neurologically healthy persons are still being actively investigated., Methods: Intraoperative transesophageal saline contrast echocardiography was performed on 50 adult patients without prior history of stroke or systemic embolism who were undergoing elective cardiovascular surgery., Results: No patient had a manifest atrial septal defect by right heart oximetric measurements or transesophageal Doppler echocardiographic examination. Eleven of the 50 patients demonstrated right to left atrial passage of saline contrast medium during apnea or after release of 20-cm H2O positive airway pressure, signifying patency of the foramen ovale. These 11 patients with a patent foramen ovale had increased total excursion of the flap valve (septum primum) of the fossa ovalis (1.3 +/- 0.7 cm) compared with findings in the 39 patients without a patent foramen ovale (0.3 +/- 0.5 cm, p < 0.001). All patients with a patent foramen ovale exhibited some mobility of the septum primum and 73% of these patients had > or = 1 cm total excursion of the septum primum. In contrast, 56% of patients without a patent foramen ovale exhibited no motion of the septum primum out of the plane of the atrial septum. The maximal diameter of the fossa ovalis was greater in patients with (1.4 +/- 0.4 cm) than in patients without (1.0 +/- 0.3 cm, p < 0.003) a patent foramen ovale., Conclusions: Hypermobility of the septum primum and enlargement of the fossa ovalis are morphologic findings that occur in the presence of a patent foramen ovale.

The impact of pericardial constraint on patterns of left ventricular filling was measured by transesophageal pulsed Doppler echocardiography in 30 patients undergoing elective nonvalvular cardiac surgery. Peak early left ventricular filling velocity increased from 0.52 +/- 0.11 to 0.56 +/- 0.15 m/s (p less than 0.05) and early left ventricular filling fraction increased from 60 +/- 9% to 65 +/- 9% (p less than 0.005) after pericardiotomy. The study group was retrospectively subdivided into two groups based on the prepericardiotomy mean right atrial pressure, an index of intrapericardial pressure and hence pericardial constraint. In 13 patients with a mean right atrial pressure less than 6 mm Hg, no significant changes in early left ventricular filling were evident after pericardiotomy. In 17 patients with a mean right atrial pressure greater than or equal to 6 mm Hg indicative of a greater degree of pericardial constraint before pericardiotomy, significant increases in peak early filling velocity (0.52 +/- 0.13 to 0.57 +/- 0.19 m/s, p less than 0.05), peak early filling rate (4.29 +/- 0.67 to 4.66 +/- 0.86 stroke volumes/s, p less than 0.05) and early left ventricular filling fraction (57 +/- 7% to 63 +/- 8%, p less than 0.001) were measured after pericardiotomy. Thus, the pericardium does constrain early left ventricular filling and its effects are more pronounced in patients with an elevated right atrial pressure.

The optimal visualization of the atrial septum and fossa ovalis by transesophageal echocardiography was utilized to demonstrate saline contrast transit across the atrial septum and to relate it to the motion of the flap valve (septum primum) of the fossa ovalis. In three cases, three distinct mechanisms of right to left interatrial shunting in the absence of right ventricular systolic hypertension were identified: 1) transient spontaneous reversal of the left to right atrial pressure differential with each cardiac cycle; 2) sustained elevation of right atrial pressure above left atrial pressure induced by respiratory maneuvers; and 3) aberrant flow redirection across the foramen ovale due to a large right atrial mass. Any of these three mechanisms may be operative during paradoxic embolism in the absence of elevation of right ventricular pressures.

This study examined the effects of global normothermic hypoperfusion on the compressed spectral array (CSA) processed electroencephalogram (EEG) during high-dose narcotic anesthesia. Fifteen patients undergoing cardiac electrophysiologic surgery were studied. The patients were anesthetized with a standard high-dose narcotic technique and then connected to a Nicolet Pathfinder I CSA EEG analysis system using seven subdermal electrodes in a modified International 10-20 configuration. There were 167 intervals of profound hypotension ranging from 8 to 96 seconds. During these periods the cerebral perfusion pressure was almost zero. Despite 38 intervals up to 32 seconds long, 6 of the 15 patients had no EEG changes. Overall, there were 36 (21.6%) ischemic EEG recordings. None of the patients developed neurological complications. The incidence of EEG changes was much lower than expected from other studies. Either the processed EEG was inherently insensitive, the high-dose narcotic masked the processed EEG effects of hypoperfusion, or the narcotic provided a previously unknown protective effect.

This study reports the intraoperative use of contrast and Doppler echocardiography techniques to diagnose patent foramen ovale (PFO). Fifty patients without known atrial septal defects undergoing elective cardiovascular surgery were studied. A 5-MHz esophageal echocardiographic probe was used to image the fossa ovalis (FO) and 10 ml agitated saline was injected into the right atrium during apnea. Echocardiographic contrast was then injected during end-inspiration at 20-cmH2O airway pressure. When opacification of the right atrium was complete, the airway pressure was released. During these maneuvers, color and pulsed-wave Doppler interrogation of the atrial septum were also performed. Right-to-left passage of saline contrast across the interatrial septum was seen in 11 of 50 patients (22%). Doppler echocardiography demonstrated a PFO in 2 patients without contrast evidence of shunting. Thus, the combination of contrast and Doppler echocardiography identified a 26% (13 of 50) prevalence of PFO, approximating the previously reported autopsy rate of 25%. These contrast and Doppler techniques may be useful in detecting patients at risk for paradoxical emboli and in identifying candidates for closure of the PFO.

Using the rapid-response thermistor pulmonary artery catheter and transoesophageal echocardiography, this study examined the effects of 100 per cent oxygen, 70 per cent nitrous oxide/30 per cent oxygen, and 70 per cent nitrogen/30 per cent oxygen on the pulmonary circulation and ventricular function in ten patients with pulmonary hypertension. In comparison with baseline measurements, nitrous oxide administration resulted in small but statistically significant (P less than 0.05) changes in mean arterial pressure (76 +/- 14 to 67 +/- 12), mean pulmonary arterial pressure (37 +/- 14 to 33 +/- 13 mmHg), and cardiac output (3.7 +/- 1.4 to 3.2 +/- 1.1 L.min-1). Seventy per cent nitrogen resulted in no significant changes from baseline. The repeat 100 per cent oxygen measurements were nearly identical to the nitrous oxide measurements. It is concluded that nitrous oxide does not exacerbate pulmonary hypertension or ventricular dysfunction during high-dose fentanyl anaesthesia in patients with mitral valvular disease.

This study documented mitral flow velocity patterns in anesthetized patients with ischemic heart disease and left ventricular dysfunction and investigated the relationship between transmitral flow velocity measurements and the hemodynamic response to ventricular pacing. Twenty-four patients in sinus rhythm without evidence of mitral valve disease undergoing elective myocardial revascularization were studied. Anesthesia consisted of a high-dose opioid-muscle relaxant-oxygen technique. After endotracheal intubation a 3.5-MHz phased-array transesophageal echocardiographic probe was inserted and positioned to obtain a long-axis view of the left atrium and left ventricle. The Doppler sample volume was placed at the mitral annulus with minimal cursor angulation, and the biphasic velocity tracing of transmitral blood flow was recorded. A hemodynamic profile was obtained, and cardiac output was measured in triplicate by thermodilution. Ventricular pacing was then instituted and the hemodynamic and thermodilution measurements were repeated. The peak early filling (E) velocity was 0.34 +/- 0.11 m/s, and the peak atrial (A) velocity was 0.38 +/- 0.09 m/s. The mean E:A ratio was 0.91 +/- 0.3, and the median value was 0.88. In sinus rhythm the cardiac index of those patients with an E:A greater than 0.88 (group 1) was 1.97 +/- 0.32 l/min and those with an E:A less than 0.88 (group 2) was 1.76 +/- 0.50 (NS). During ventricular pacing the patients in group 1 (1.56 +/- 0.32 l/min) had significantly higher cardiac indices than those in group 2 (1.21 +/- 0.31 l/min) (P less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

In patients with pre-existing pulmonary hypertension, severe pulmonary vasoconstriction has been observed following protamine administration. Thromboxane A2, a potent vasoconstrictor, is capable of producing increases in pulmonary vascular resistance, and animal studies suggest that heparin-protamine complexes stimulate thromboxane A2 synthesis. This study assessed the effect of protamine administration on hemodynamics and on plasma thromboxane A2 and its biologic antagonist, prostacyclin, by serial measurement of the stable metabolites, thromboxane B2 and 6-keto-prostaglandin F1 alpha, respectively. Ten adults with pulmonary artery hypertension undergoing elective mitral valve replacement were studied. After termination of cardiopulmonary bypass, baseline hemodynamic measurements were obtained and arterial blood for prostanoid analysis was sampled. Hemodynamic and prostanoid measurements were obtained 5, 10, 15, and 30 minutes after the protamine infusion began. Prostanoid levels were performed by double antibody radio-immunoassay. No significant hemodynamic changes occurred and no significant changes in prostanoid levels were observed. It is concluded that in patients with pulmonary hypertension, heparin-protamine complexes do not consistently raise circulating thromboxane levels, and the relationships among prostanoids, pulmonary hypertension, and systemic hypotension are still not clear.

Transesophageal echocardiography (TEE) is a new monitoring technique that images the heart and provides information on regional wall motion and left ventricular filling. However, despite its potential for inaccuracy due to its retrocardiac position and angulation, TEE has not been validated by another imaging technique. Using direct on-heart echocardiography (OHE) as a standard, the authors evaluated the ability of TEE to measure accurately left ventricular end-diastolic area (EDa), end-systolic area (ESa), and ejection fraction area (EFa). Ten patients with coronary artery disease without evidence of valvular dysfunction undergoing myocardial revascularization were studied. A Diasonics 3.5 MHz two-dimensional TEE probe was introduced into each patient's esophagus and positioned to obtain a view equivalent to the parasternal short-axis projection. A similar view was obtained by OHE using a sterilely prepared 3 MHz ATL probe placed on either the pericardium or epicardium. In each patient, immediately prior to and after pericardiotomy, both transesophageal and on-heart short-axis views at the level of the papillary muscles were obtained. Using a dedicated Diasonics computer echoanalyzer, EDa and ESa from four consecutive cardiac cycles were outlined with a light pen and averaged. EFa was calculated by the formula EFa = (EDa - ESa)/EDa. Seventeen comparable transesophageal and on-heart echocardiograms were obtained. ESa by TEE correlated well with ESa by OHE (15.13 +/- 9.62 cm2 vs. 14.92 +/- 10.53 cm2; r = 0.94). Similar results were obtained for EDa (27.75 +/- 9.88 cm2 vs. 30.40 +/- 13.99 cm2; r = 0.88) and EFa (0.49 +/- 0.17 vs. 0.54 +/- 0.13; r = 0.92). filling and ejection.

The treatment of skeletal injuries often requires immobilization for extended periods. Immobilization causes muscle disuse atrophy, which extends the duration of incapacitation following the healing of the skeletal injury. To evaluate the role of immobilization position on the skeletal muscle, an experimental study using an animal model was undertaken. Cats were divided into four groups, with one hind limb immobilized in a plaster spica cast such that the gastrocnemius and soleus muscles were held in either a stretched, shortened, or neutral position. After four weeks of immobilization, functional and quantitative assays of muscle tissue were obtained and correlated. The shortened muscles weighed less, had a lower total content and concentration of myofibrillar proteins (the contractile protein of muscle tissue), and generated less maximum tetanic tension than either the muscles held in neutral or stretched length position. Decreased maximum tetanic tension resulted from the preferential loss of contractile protein. The remaining myofibrillar protein in the shortened muscle showed contractile dysfunction. The ability to maintain initial twitch strength (an endurance function) for five minutes varied with position but was not statistically significant in this study. The data suggest that muscle maintained in a shortened position atrophies more rapidly, with greater loss in contractile function and myofibrillar and sarcoplasmic proteins than the stretched and neutrally positioned muscles.

The effects of the Trendelenburg (TREND) position and passive straight leg raising (PLR) on cardiopulmonary performance in 18 anesthetized patients undergoing myocardial revascularization were studied with a two-dimensional transesophageal echocardiography probe and a thermodilution right ventricular ejection fraction (RVEF) pulmonary artery catheter. The TREND position (at 20 degrees) and PLR (at 60 degrees) were studied in relation to the level-supine position in random order. At 3 min, the TREND caused significant (p less than .05) decreases in heart rate (62 +/- 9 to 58 +/- 10 [SD] beat/min) and RVEF (0.48 +/- 0.11 to 0.44 +/- 0.10), and significant increases in mean arterial pressure (77 +/- 11 to 82 +/- 11 mm Hg), mean pulmonary artery pressure (16 +/- 4.3 to 19 +/- 5.5 mm Hg), wedge pressure (11 +/- 4 to 13 +/- 4 mm Hg), cardiac index (CI) (2.36 +/- 0.79 to 2.52 +/- 0.93 L/min.m2), right ventricular end-systolic volume index (44 +/- 21 to 58 +/- 21 ml/m2), right ventricular end-diastolic volume index (83 +/- 24 to 102 +/- 22 ml/m2), and shunt fraction (0.16 +/- 0.06 to 0.19 +/- 0.06). CVP and left ventricular areas did not change significantly. PLR had similar effects as the TREND position, except CI did not change significantly. Thus, the TREND and PLR resulted in minor hemodynamic improvement with right ventricular dilation, decreased RVEF, and impaired oxygenation in the anesthetized cardiac surgical patient.

The effects of doxacurium chloride, a new long-acting non-depolarizing neuromuscular blocking drug, on cardiac performance were studied in 45 patients undergoing high-dose fentanyl-diazepam-oxygen anaesthesia for cardiac surgery. Data were collected at baseline (10 min after tracheal intubation), and at 2, 5 and 10 min after an i.v. bolus of doxacurium with a rapid-response thermistor pulmonary arterial catheter, using two-dimensional transoesophageal echocardiography, and direct arterial pressure measurement. The patients were allocated to four groups based on the type of surgery and dose of doxacurium (0.05 or 0.08 mg kg-1). No changes in left or right ventricular dimensions or contractility were detected in any group. Although significant changes (P less than 0.05) occurred in several groups, all these changes were clinically insignificant (less than 10% change from baseline values), and were similar to those seen in unstimulated anaesthetized patients. Doxacurium appears to be a safe drug for use in patients undergoing cardiac surgery, and is devoid of significant cardiovascular side effects in the doses tested.

Whether the normal pericardium exerts a constraining effect on left ventricular (LV) diastolic compliance and/or systolic function is controversial. Left ventricular filling and performance were studied in 15 patients by two-dimensional transesophageal echocardiography (2D-TEE) measuring end-diastolic area (EDa), end-systolic area (ESa), ejection fraction area (EFa), and hemodynamics immediately pre- and post-pericardiotomy. To diminish the influences of other variables such as surgical stimulation, chest wall constraint, and autoregulation, measurements were performed in deeply anesthetized patients with the chest fully opened immediately before and after pericardiotomy (PC). No significant echocardiographic or hemodynamic changes were observed after PC. Although alterations in compliance cannot be excluded, no significant changes in LV diastolic filling (EDa, pulmonary capillary wedge pressure [PCWP]) or systolic performance (EFa, cardiac output [CO]) were found. Therefore, it is concluded that the normal pericardium does not exert a measurable constraining effect on LV performance.