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Biomedical subjects

Pierre Couture

Publications and source records attributed to Pierre Couture.

13 recordsLinked to original sources
PubMed2003

Partial inferior vena cava snaring to control ischemic left ventricular dysfunction.

PURPOSE: To describe the hemodynamic and intraoperative transesophageal echocardiographic evaluation of cardiac systolic and diastolic function in a patient undergoing off-pump coronary artery bypass graft (OP-CABG) surgery who developed pulmonary artery hypertension controlled by inferior vena cava (IVC) snaring. CLINICAL FEATURES: A 63-yr-old man was referred to our hospital for elective OP-CABG surgery. His preoperative ventriculopathy revealed a decreased systolic function (ejection fraction of 35%), and a mild mitral regurgitation. Intraoperatively, after application of the stabilizer and clamping of the diagonal artery, he developed a marked increase in pulmonary artery pressure (PAP) with a decrease in systemic arterial pressure, non responsive to iv norepinephrine and nitroglycerin. Transesophageal echocardiographic evaluation revealed a marked decrease in systolic function and presence of a restrictive diastolic filling pattern. Partial IVC snaring decreased the venous return and PAP decreased cardiac chamber dimensions, improved systolic function and improved diastolic filling pattern. CONCLUSION: Partial IVC snaring was used successfully to treat a hemodynamically unstable patient with sudden increase in PAP caused by ischemic left ventricular failure during OP-CABG.

Coronary Artery Bypass↗
PubMed2003

Transesophageal echocardiography monitoring in the intensive care department: the management of hemodynamic instability secondary to thoracic tamponade after single lung transplantation.

A 65-year-old woman with pulmonary fibrosis had hemodynamic instability develop after single lung transplantation. Transesophageal echocardiography was useful in determining the cause of hemodynamic instability, which was secondary to thoracic tamponade. Furthermore, transesophageal echocardiography monitoring was important in the decision to initiate extracorporeal membrane oxygenation to evaluate adequate positioning of the cannula and in the extracorporeal membrane oxygenation weaning process.

Aged↗
PubMed2003

Inhaled epoprostenol (prostacyclin) and pulmonary hypertension before cardiac surgery.

OBJECTIVE: Pulmonary hypertension is commonly found in patients undergoing valvular surgery and can be worsened by cardiopulmonary bypass. Inhaled epoprostenol (prostacyclin) has been used for the treatment of pulmonary hypertension, but its effects compared with those of placebo on hemodynamics, oxygenation, echocardiographic examination, and platelet function have not been studied during cardiac surgery. METHODS: Twenty patients with pulmonary hypertension undergoing cardiac surgery were randomized in a double-blind study to receive inhaled epoprostenol (60 microg) or placebo. The inhalation occurred after induction of anesthesia and before surgical incision. The effects on left and right systolic and diastolic cardiac functions evaluated by means of pulmonary artery catheterization and transesophageal echocardiography, as well as oxygenation and platelet aggregation, were studied. RESULTS: Inhalation of epoprostenol significantly reduced indexed right ventricular stroke work from 10.7 +/- 4.57 g. m. m(-2) to 7.8 +/- 3.94 g. m. m(-2) (P =.003) and systolic pulmonary artery pressure from 48.4 +/- 18 mm Hg to 38.9 +/- 11.9 mm Hg (P =.002). The effect was correlated with the severity of pulmonary hypertension (r = 0.76, P =.01) and was no longer apparent after 25 minutes. There was no significant effect on systemic arterial pressures, left ventricular function, arterial oxygenation, platelet aggregation, and surgical blood loss. CONCLUSION: Inhaled epoprostenol reduces pulmonary pressure and improves right ventricular stroke work in patients with pulmonary hypertension undergoing cardiac surgery. A dose of 60 microg is hemodynamically safe, and its effect is completely reversed after 25 minutes. We did not observe any evidence of platelet dysfunction or an increase in surgical bleeding after administration of inhaled epoprostenol.

Administration, Inhalation↗
PubMed2002

Mechanisms of hemodynamic changes during off-pump coronary artery bypass surgery.

PURPOSE: To describe the mechanisms of hemodynamic changes during off-pump coronary artery bypass graft surgery (OP-CABG). SOURCE: Pertinent medical literature in the English and French languages was identified through a Medline computerized literature search and a manual search of selected articles, using off-pump coronary artery surgery, beating heart surgery, hemodynamic, and transesophageal echocardiography as key words. Human and animal studies were included. PRINCIPAL FINDING: Hemodynamic variations in OP-CABG may be due to mobilization and stabilization of the heart, or myocardial ischemia occurring during coronary occlusion. Suction type and compression type stabilizers produce hemodynamic effects through different mechanisms. Heart dislocation (90 degrees anterior displacement) and compression of the right ventricle to a greater extent than the left ventricle are responsible for hemodynamic alterations when using suction type stabilizers. Compression of the left ventricular outflow tract and abnormal diastolic expansion secondary to direct deformation of the left ventricular geometry are proposed mechanisms for hemodynamic derangements with compression type stabilizer. Coronary occlusion during the anastomosis can have additional effects on left ventricular function, depending on the status of collateral flow. The value and limitations of electrocardiographic (ECG), hemodynamic and echocardiographic monitoring modalities during OP-CABG are reviewed. CONCLUSIONS: In summary, hemodynamic changes which can either be secondary to the stabilization technique or to transient ischemia represent an important diagnostic challenge during off-bypass procedures. The mechanism can vary according to the stabilization system. Current monitoring such as ECG and hemodynamic monitoring are used but remain limited in establishing the cause of hemodynamic instability. Transesophageal echocardiography is used in selected patients to diagnose the etiology of hemodynamic instability and can direct therapy, particularly in those with severe myocardial systolic and diastolic dysfunction, mild to moderate mitral regurgitation, or for patients who are unstable during the procedure.

Animals↗
PubMed2002

A comprehensive strategy to avoid transesophageal echocardiography probe damage.

PURPOSE: To describe the factors predisposing to transesophageal echocardiography (TEE) probe damage and to propose a strategy aimed at preventing damage to the TEE probe. Description of equipment and procedures: Damage to the TEE probe can occur anywhere and anytime during use in the operating room (OR) or when the probe is not in use in the OR, such as in the cleaning room, during storage or during transport of the probe. The components of the strategy used in our institution to avoid probe damage are: 1) storage of the probe in a dedicated holder in the OR when it is not in use, 2) use of a lexan box in the OR to protect the probe connector, 3) use of a custom-made holder when the probe is inserted in the patient, 4) use of a dedicated holder for soiled TEE probe storage in the cleaning room and for subsequent probe storage. CONCLUSION: We describe a comprehensive strategy designed to decrease TEE probe damage and the associated expenses. Further studies will be required to determine the effectiveness of the proposed measures.

Echocardiography, Transesophageal↗
PubMed2002

Perioperative use of transesophageal echocardiography by anesthesiologists: impact in noncardiac surgery and in the intensive care unit.

BACKGROUND: The American Society of Anesthesiologists (ASA) has published practice guidelines for the use of perioperative transesophageal echocardiography (TEE) but the role and impact of TEE performed by anesthesiologists outside the cardiac operating room (OR) is still poorly explored. We report our experience in the use of TEE in the noncardiac OR, the recovery room and in the intensive care unit (ICU) in a university hospital, and analyze the impact of TEE on clinical decision making. METHODS: Two hundred fourteen patients were included and TEE indications were classified prospectively according to the ASA guidelines. The examinations and data sheets were reviewed by two anesthesiologists with advanced training in TEE. For each examination, it was noted if TEE altered the management according to five groups: 1) changing medical therapy; 2) changing surgical therapy; 3) confirmation of a diagnosis; 4) positioning of an intravascular device; and 5) TEE used as a substitute to a pulmonary artery catheter. RESULTS: Eighty-nine (37%), 67 (31%) and 58 (27%) patients had category I, II and III indications. The impact was more significant in category I where TEE altered therapy 60% of the time compared with 31% and 21% for categories II and III (P < 0.001). The most frequent reason for changing management was a modification in medical therapy in 53 instances (45%). CONCLUSION: Our results confirm a greater impact of TEE performed by anesthesiologists on clinical management for category I compared to category II and III indications in the noncardiac OR surgical setting and in the ICU.

Anesthesiology↗
PubMed2002

Changing pattern in beating heart operations: use of skeletonized internal thoracic artery.

BACKGROUND: The use of skeletonized internal thoracic artery (ITA) was reported to be technically and hemodynamically beneficial in conventional coronary artery bypass grafting with cardiopulmonary bypass assistance. The purpose of this study is to evaluate the impact of changing from conventional to skeletonized ITA harvesting on early off-pump coronary artery bypass grafting outcome. METHODS: Between 1996 and 2001, 640 patients underwent systematic off-pump coronary artery bypass grafting (single surgeon experience). The ITA was pedicled (P) in the first consecutive 440 patients and skeletonized (S) in the subsequent 200 consecutive patients. Mean age, preoperative risk factors, sex, number of involved territories, and incidence of reoperations were similar in both groups. RESULTS: In group S, number of ITAs per patient (1.7 +/- 0.08 versus 1.2 +/- 0.05; p < 0.001), bilateral ITA (46% versus 27%; p < 0.001), ITA sequential grafts (27% versus 1%; p < 0.001), and T grafts (16% versus 3%; p < 0.001) were higher. Deep sternal infections were comparable in both groups (group S: 1%, group P: 1.2%; p = 0.38). Perioperative myocardial infarction, maximal creatinine kinase-MB level, and requirement for more than 24 hours of inotropic support were comparable in both groups. Thirty-day mortality was also similar (S: 1.7%, P: 1.6%). CONCLUSIONS: Changing to routine use of skeletonized ITA in off-pump coronary artery bypass grafting is a safe alternative to routine pedicled ITA. In our experience, this procedure has facilitated the use of ITA anastomosis without increasing sternal wound complications.

Aged↗
PubMed2002

Hemodynamic changes during off-pump CABG surgery.

OBJECTIVES: The purpose of this study was to assess the patients' hemodynamics during off-pump coronary artery bypass graft (OPCABG) surgery. METHODS: Continuous monitoring of the mean systemic arterial pressure (SAP), mean pulmonary arterial pressure (PAP), mixed venous oxygen saturation (SvO(2)) and cardiac output index (COI) was done on 55 patients undergoing complete OPCAB revascularization. Hemodynamic changes were recorded at the completion of the anastomosis before releasing coronary snaring and stabilization and compared to baseline. RESULTS: The mean age of the patients was 66.4+/-9.2 years, and on average 3.3+/-0.8 grafts per patient were performed. The average SAP drop after manipulations was -8.3+/-16.9 mmHg for the left anterior descending artery (LAD), -13.5+/-19.6 mmHg for the diagonal artery (DG), -14.6+/-13 mmHg for the optuse marginal artery (OM), and -14.2+/-13.5 mmHg for the right coronary artery. This was significant for all territories (P<0.01). The PAP significantly increased in all territories except OM (LAD: 3.7+/-6.3 mmHg, DG: 4.3+/-8.6 mmHg, OM: 1.1+/-7.2 mmHg, posterior descending artery: 2.7+/-5.6 mmHg; P<0.05). Variations in COI were significant in all territories (P<0.01) but more significantly in LAD and DG territories (-15+/-3% and -13+/-9%, respectively). The SvO(2) variations were <10% for all territories and reached only borderline significance (P=0.05) in all territories except OM. All these hemodynamic changes were well tolerated by all patients. CONCLUSIONS: Manipulation of the beating heart during OPCABG surgery brings significant fluctuations in the patients' hemodynamics. Mean PAP increase and COI drop were more significant during manipulation of the anterior territories suggesting a more severe diastolic restrictive disease during anterior wall manipulation.

Aged↗
PubMed2002

Mitral Doppler indices are superior to two-dimensional echocardiographic and hemodynamic variables in predicting responsiveness of cardiac output to a rapid intravenous infusion of colloid.

UNLABELLED: We hypothesized that mitral flow (MF) Doppler measurements could be used to predict cardiac output (CO) responsiveness to fluid challenge. Fourteen patients with normal systolic and diastolic function, scheduled for coronary artery bypass graft surgery, were evaluated as part of a pilot study in which preload was varied immediately before the beginning of cardiopulmonary bypass. A Validation group of 36 patients with different levels of systolic and diastolic function received a rapid infusion of 500 mL of 10% pentastarch. By use of transesophageal echocardiography, we measured left ventricular end-diastolic area, pulsed Doppler indices of the MF and pulmonary venous flow, and standard hemodynamic variables during acute volemic variations. A baseline measurement was first recorded, followed by measurements taken after a decrease (211 +/- 87 mL) and then an increase (176 +/- 149 mL) in preload (pilot study) and before and after 500 mL of pentastarch (validation study). In the pilot study, we found that a low velocity/time integral (VTI) E wave/A wave (E/A) ratio was associated with a larger increase in CO secondary to an increase in preload (r = 0.64, P < 0.05). Stepwise linear regression identified Doppler measurements of the mitral VTI E/A ratio as the most important variable to predict the increase in CO after fluid infusion. In the validation study, a mitral E/A ratio <1.26 before fluid infusion best predicted a 20% increase in stroke volume (receiver operating characteristic curve, 71%; P < 0.05), whereas no other hemodynamic or echocardiographic variable predicted preload responsiveness. We conclude that the MF Doppler filling pattern is an important factor to predict the increase in CO after intravascular fluid challenge in patients undergoing coronary artery bypass grafting. IMPLICATIONS: In the presence of low cardiac output, the clinician's ability to identify which patients are more likely to benefit from volume administration to improve hemodynamic status while avoiding fluid overload is important. The analysis of Doppler measurement of the mitral flow as an indirect indicator of the individual diastolic pressure/volume relationship may be useful to predict the intravascular volume responsiveness in patients undergoing coronary artery bypass graft surgery.

Adult↗
PubMed2002

The hemodynamically unstable patient in the intensive care unit: hemodynamic vs. transesophageal echocardiographic monitoring.

OBJECTIVE: Transesophageal echocardiography is a diagnostic and monitoring modality. The objectives of our study were to compare the diagnoses obtained with continuous transesophageal echocardiography and hemodynamic monitoring in the intensive care unit, to determine interobserver variability of diagnosis obtained with both modalities, and to evaluate its impact. DESIGN: Prospective cohort study. SETTING: Surgical intensive care unit. PATIENTS: Consecutive hemodynamically unstable patients after cardiac surgery. INTERVENTIONS: At admission, unstable patients were monitored during 4 hrs with transesophageal echocardiography and standard hemodynamic monitoring. The critical care physician evaluated the patients based on all information except the transesophageal echocardiography at 0, 2, and 4 hrs and formulated a hypothesis on the most likely cause of hemodynamic instability. Transesophageal echocardiography information was provided after each evaluation. To evaluate interobserver variability, all the hemodynamic and echocardiographic information was gathered, randomized, and evaluated by five clinicians for the hemodynamic data and five echocardiographers for the transesophageal echocardiography data. The evaluators were blinded to all other information. Kappa statistics were used to evaluate agreement. Impact of transesophageal echocardiography was assessed retrospectively by using the Deutsch scale. RESULTS: Twenty patients qualified for the study. The agreement between the hemodynamic and echocardiographic diagnosis showed a kappa at admission, 2 hrs, and 4 hrs of 0.33, 0.47, and 0.28. The interobserver agreement for the initial diagnosis (p =.014) and between all evaluators (p <.001) was significantly higher in the echocardiographic compared with the hemodynamic group. The transesophageal echocardiographic information was considered retrospectively to be essential in 34% and valuable in 34% of cases. CONCLUSIONS: These observations support the belief that transesophageal echocardiographic monitoring in the intensive care unit is associated with higher interobserver agreement in diagnosing and excluding significant causes of hemodynamic instability for postoperative cardiac surgical patients.

Adult↗
PubMedDate not supplied

Expert consensus for training in perioperative echocardiography in the province of Quebec.

PURPOSE: Establish an expert consensus for training in perioperative echocardiography in the province of Quebec. METHODS: Cardiac anesthesiologists practicing in the province of Quebec with expertise in echocardiography were involved in the development of a multicentre expert consensus on training in perioperative echocardiography. Guidelines for training in adult echocardiography, transesophageal echocardiography and perioperative echocardiography by the American Society of Echocardiography (ASE), the American College of Cardiology (ACC) and/or the Society of Cardiovascular Anesthesiologists (SCA) were reviewed. RESULTS: A basic, advanced and director level of expertise were identified for training in perioperative echocardiography. The total number of echocardiographic examinations to achieve each of these levels of expertise remains unchanged from the 2002 ASE-SCA guidelines. However, the recommended proportion of examinations performed personally is increased in the Quebec expert consensus for both the basic and the advanced level of training to ensure proficiency in echocardiography while providing anesthesia care to the patient. A level of autonomy in perioperative echocardiography is also identified in the basic level of training as defined in the Quebec expert consensus. Maintenance of competence, certification in the perioperative transesophageal echocardiography (PTE) examination and duration of training are outlined for each of the three levels of training in the Quebec expert consensus but are not part of the recent 2002 ASE-SCA guidelines. CONCLUSION: Adequate perioperative echocardiographic training is an important aspect of cardiovascular anesthesia. The ACC, ASE and SCA guidelines for training in echocardiography were modified to reflect the expert consensus of anesthesiologists in the province of Quebec.

Anesthesiology↗