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Biomedical subjects

R Martineau

Publications and source records attributed to R Martineau.

At least 19 recordsLinked to original sources

A phase II dose-response study of hemoglobin raffimer (Hemolink) in elective coronary artery bypass surgery.

BACKGROUND: We performed this study to determine the dose-response of hemoglobin raffimer administered in conjunction with intraoperative autologous donation in patients undergoing coronary artery bypass grafting surgery. A secondary objective was to evaluate hemoglobin raffimer for reducing the incidence of allogeneic red blood cell transfusions. METHODS: This was a phase II, single-blind, multicenter, placebo-controlled, open-label study. Patients undergoing coronary artery bypass grafting with cardiopulmonary bypass and intraoperative autologous donation were randomized to receive a single dose of hemoglobin raffimer or control (10% pentastarch). Patients were sequentially enrolled in a dose block of 250, 500, 750, and 1000 mL. RESULTS: Sixty patients received hemoglobin raffimer (n = 30) or control (n = 30). Hemoglobin raffimer was well tolerated. Most (98%) adverse events were mild or moderate in severity. There was an expected dose-dependent increase in the incidence of blood pressure increases and jaundice in hemoglobin raffimer-treated patients. In a dose-pooled analysis of hemoglobin raffimer versus control, increased blood pressure (43% vs 17%), nausea (37% vs 33%), and atrial fibrillation (37% vs 17%) were the most frequently reported adverse events. All serious adverse events were considered unrelated or unlikely to be related to study drug. No hemoglobin raffimer-treated patient required an intraoperative allogeneic red blood cell transfusion, compared with 5 (17%) pentastarch-treated patients (P =.052). This advantage of hemoglobin raffimer was maintained at 24 hours after surgery (7% vs 37%; P =.010) and up to 5 days after surgery (10% vs 47%; P =.0034). CONCLUSIONS: Hemoglobin raffimer was not associated with any serious adverse events in patients undergoing primary coronary artery bypass grafting with cardiopulmonary bypass and intraoperative autologous donation in a dose-response study up to 1000 mL. Hemoglobin raffimer was effective in facilitating decreased exposure or avoidance of allogeneic red blood cell transfusions when used in conjunction with intraoperative autologous donation.

Adult↗

[Beating heart surgery and left ventricular dysfunction].

We report our experience with systematic coronary revascularization on the beating heart among patients with left ventricular dysfunction as defined by a left ventricular ejection fraction < or = 40%. Between September 1996 and April 2000, 500 off-pump (OPCAB) revascularizations were performed (95% of all revascularizations for the same time frame, single surgeon). Among them, 76 patients qualified as left ventricular dysfunction and were compared to a similar cohort of 237 patients operated on with cardiopulmonary bypass (CPB) during the same time frame. Age and sex distribution, average preoperative left ventricular ejection fraction and incidence of preoperative unstable angina were the same for both groups. On average, 3.04 +/- 0.89 and 2.97 +/- 0.69 grafts/patient were made in the OPCAB and CPB groups respectively (p = NS). Complete revascularization was achieved in 95% of the OPCAB group. Incidence of preoperative intra-aortic balloon assistance were higher in OPCAB (22% versus 9%, p = 0.005) whereas postoperative need for new intra-aortic balloon assistance was higher in CPB (8% versus 0%, p = 0.02). Incidence of postoperative myocardial infarction was comparable in both groups (6.5% versus 5.5%). Maximal creatinine phosphate of myocardial origin were lower in OPCAB group (beating heart: 32 +/- 52%, cardiopulmonary bypass: 45 +/- 51%, p = 0.055). Operative mortality was lower in OPCAB group although it did not reach statistical significance (beating heart: 2.6% versus cardiopulmonary bypass: 4.6%, p = 0.3). Complete coronary revascularization on the beating heart can be achieved in patients with left ventricular dysfunction with excellent outcome and low operative mortality.

Cardiac Surgical Procedures↗

Outcome with high blood lactate levels during cardiopulmonary bypass in adult cardiac operation.

BACKGROUND: High blood lactate levels during cardiopulmonary bypass (CPB) are associated with tissue hypoperfusion and may contribute to postoperative complications or death. The objective of this study was to determine an association between blood lactate levels during CPB and perioperative morbidity and mortality. METHODS: We reviewed 1,376 patients who underwent cardiac operation with CPB. Patients with abnormal preoperative blood lactate levels were excluded (n = 101). Blood lactate concentration during CPB, clinical data, and perioperative events were recorded. RESULTS: Peak blood lactate levels of 4.0 mmol/L or higher during CPB were present in 227 patients (18.0%). Postoperative mortality was higher in this group than in the patients who had peak blood lactate levels of less than 4.0 mmol/L during CPB (11.0% versus 1.4%; p < 0.001, relative risk [RR] = 9.0). Postoperative hemodynamic instability occurred in 29.5% of patients with elevated levels of lactate during CPB compared with 10.9% of patients with lower lactate levels (p < 0.001, RR = 3.4). Overall, major postoperative complications occurred in 43.2% and 21.8% of patients in each group, respectively (p < 0.001, RR = 2.7). Logistic regression analysis revealed that peak blood lactate levels of 4.0 mmol/L or higher during CPB were strongly associated with postoperative mortality (p = 0.0001) and morbidity (p = 0.013). CONCLUSIONS: Blood lactate concentration of 4.0 mmol/L or higher during CPB identifies a subgroup of patients with increased risk of postoperative morbidity and mortality.

Adult↗

Low-dose aprotinin is ineffective to treat excessive bleeding after cardiopulmonary bypass.

BACKGROUND: Uncontrolled clinical experience at our institution suggested that low-dose aprotinin could control excessive bleeding after cardiopulmonary bypass (CPB). A randomized clinical trial was conducted to determine the efficacy of low-dose aprotinin in the treatment of hemorrhage after cardiac surgery. METHODS: One hundred seventy-one patients undergoing cardiac surgery with CPB were included. Forty-four patients (26%) bled significantly in the intensive care unit (>100 mL/h) and received either aprotinin (200,000 KIU bolus + 100,000 KIU/h for 8 hours) or placebo in addition to our standard management of excessive bleeding. RESULTS: Median bleeding before study drug administration was not different between aprotinin (200 mL) and placebo (212.5 mL) groups. Bleeding decreased significantly with time and similarly in both groups. Ninety-five percent of patients required transfusions in both groups. Median blood products transfused were 13 and 8 units per patient in the aprotinin and placebo groups respectively (p = NS). CONCLUSIONS: Routine administration of low-dose aprotinin as part of the treatment protocol to control hemorrhage after CPB does not reduce bleeding or transfusion requirements and, therefore, cannot be recommended.

Aged↗

Systematic off-pump coronary artery revascularization in multivessel disease: experience of three hundred cases.

OBJECTIVE: We sought to report our recent experience with off-pump coronary artery revascularization in multivessel disease. METHODS: Between October 1996 and December 1998, 300 off-pump beating heart operations were performed at the Montreal Heart Institute by a single surgeon, representing 94% of all procedures undertaken during this same time frame (97% for 1998). This cohort of patients was compared with 1870 patients operated on with cardiopulmonary bypass from 1995 to 1996. RESULTS: Mean age, sex distribution, and preoperative risk factors were comparable for the two groups. On average, 2.92 +/- 0.8 and 2.84 +/- 0.6 grafts per patient were completed in the beating heart and cardiopulmonary bypass groups, respectively. A majority of patients (70%) had either a triple or quadruple bypass. Coronary anastomoses were achieved with myocardial mechanical stabilization and heart "verticalization." Ischemic time was shorter in the beating heart group (29.8 +/- 0.9 vs 45 +/- 0.4 minutes, P <.05). Similarly, the need for transfusion was significantly less in the beating heart group (beating heart operations, 34%; cardiopulmonary bypass, 66%; P <.005). Reduced use of postoperative intra-aortic counterpulsation, as well as a lower rise in creatine kinase MB isoenzyme, was observed in the beating heart group. Operative mortality rates (beating heart operations, 1. 3%; cardiopulmonary bypass, 2%) and perioperative myocardial infarction (beating heart operations, 3.6%; cardiopulmonary bypass, 4.2%) were comparable for the two groups. CONCLUSION: In a majority of patients, off-pump complete coronary artery revascularization is an acceptable alternative to conventional operations, yielding good results given progressive experience, rigorous technique, and adequate coronary artery stabilization.

Cardiopulmonary Bypass↗

Vertical and horizontal transmission of Neospora caninum in dairy herds in Québec.

Neospora caninum is an important cause of abortion in dairy cattle. The objective of this observational study was to estimate the rate of vertical transmission of N. caninum in dairy herds in Québec and to investigate horizontal transmission in the same herds. The genealogy of cows from 23 dairy herds were examined. Prevalence of seropositive animals in herds studied varied from 4.3% to 61.8% (average, 21.9%). The overall rate of vertical transmission was estimated to be 44.4%, varying from 0% to 85.7%. Seven cases of horizontal transmission were identified in 6 of the 23 herds studied. Estimated vertical transmission rate varied from herd to herd, but appeared to be higher in herds with a high prevalence of seropositive animals. Although horizontal transmission was identified in 6 herds, it does not appear to be the major route of infection for N. caninum.

Animal Husbandry↗

Left main coronary artery stenosis: early experience with surgical revascularization without cardiopulmonary bypass.

BACKGROUND: To determine the safety of surgical revascularization without cardiopulmonary bypass (CPB) in left main stem (LMS) coronary stenosis. METHODS AND RESULTS: Between October 1996 and April 1998, 67 consecutive patients with a > or =50% LMS stenosis underwent coronary revascularization without bypass (BH) and were compared to a contemporary group of 160 patients revascularized with conventional bypass (CPB). Mean ages in both groups were similar: 63.1 and 64.5 years in BH and CPB groups respectively (p=0.91). Significant triple vessel disease occurred in 40 (80%) and 75 (47.5%) patients in BH and CPB groups respectively (p=NS). Average grafts per patient was numbered 3.1 in BH group and 2.9 in CPB group (p=NS). The perioperative infarction rate (defined arbitrarily as a CK-MB >100 U/l) was 4% (2 patients, excluding 1 preoperative infarct) and 3.1% (5 patients, excluding 2 preoperative infarcts) in groups BH and CPB respectively (p=0.28). Postoperative blood transfusion requirements were less in BH group (19 patients, 38%) compared to CPB group (103 patients, 64.4%), (p=0.04). Postoperative inotropic requirements were similar in both groups; BH group (15 patients, 30%) and CPB group (72 patients, 45%). Mean hospital stay was 6.4 and 7.6 days in BH and CPB groups respectively (p=0.49). The hospital mortality rate was 0% and 3.8% (6 patients) in BH and CPB groups respectively (p=NS). CONCLUSIONS: Our early experience suggests that non-CPB surgical revascularization in LMS stenosis is a feasible and safe alternative to conventional cardiopulmonary bypass.

Adult↗

[Systemic coronary surgery in the beating heart. Experience in 250 cases].

OBJECT: To report our recent experience with off-pump coronary artery revascularization in multi-vessel disease. METHODS: Between October 1996 and August 1998, 250 off-pump (OP) procedures were completed at the Montreal Heart Institute, representing more than 90% of all procedures done during the same time frame (97% for 1998). These patients have been compared to 1870 patients operated upon under cardiopulmonary bypass during the years 1995-1996 (CPB). RESULTS: Mean age, sexe distribution, and preoperative risk factors were comparable for both groups. On average 2.89 +/- 0.8 and 2.84 +/- 0.6 grafts/patient were completed in OP and CPB groups respectively. A majority (70%) of patients had either a triple or quadruple bypass. Coronary anastomoses were achieved with myocardial mechanical stabilization and heart "verticalization". Ischemic time was shorter in the OP group (29.8 +/- 0.9 vs 45 +/- 0.4 min, p < 0.05). Similarly, need for transfusion was significantly less (OP: 34 vs CPB: 66%, p < 0.005). Use of postoperative intra-aortic counterpulsation as well as the raise of CK-MB were lesser in the OP group. Operative mortality (OP: 1.6%, vs CPB: 2%, p = ns) and perioperative myocardial infarction rate (OP: 3.6% vs CPB: 4.2) were comparable for both groups. CONCLUSION: Off-pump complete coronary artery revascularization is an acceptable alternative to conventional surgery in a majority of patients with good results given progressive experience, rigorous technique, and adequate coronary artery stabilization.

Aged↗

[Left main coronary artery stenosis and revascularization in the beating heart. Short- and long-term experience].

OBJECT: To determine the safety of surgical revascularization without cardiopulmonary bypass in left main coronary artery stenosis. METHODS: Between October 1996 and October 1998, 67 patients with a left main stem stenosis (LMS) (> 50%) underwent revascularization on beating heart surgery (BHS) and were compared to a cohort of 192 patients with LMS disease that were operated on under cardiopulmonary bypass (CPB) during 1996. RESULTS: Mean age and sex distribution and prevalence of preoperative risk factors were the same in both groups as well as the average number of grafts per patient was 3.1 +/- 0.7 and 2.9 +/- 0.7 in BHS and CPB groups respectively. Perioperative infarction rate (defined arbitrarily as a CK-MB > 100 IUL) was 2.9% in BHS group and 3.1% in CPB group. Postoperative blood transfusion requirements were less in BHS group (38%) compared to CPB group (64%), p < 0.05. Inotropic requirements postoperatively were similar in both groups. Hospital stay was shorter in BHS group (6.8 days) compared to CPB group (7.6 days) although not significant. There was no operative mortality in BHS group whereas 4.7% died postoperatively in CPB group. CONCLUSION: Our experience suggests that non-bypass surgical revascularization is a feasible and safe alternative to conventional cardiopulmonary bypass.

Aged↗

Can L-arginine improve myocardial protection during cardioplegic arrest? Results of a phase I pilot study.

BACKGROUND: L-arginine appears to improve myocardial protection during cardioplegic arrest in animal models. METHODS: To study the clinical effect and safety of L-arginine in humans, a phase I pilot study was performed with 50 patients who underwent coronary artery bypass grafting. We randomly assigned half to a treatment group, which received 1 g of L-arginine administered during the first 30 minutes of cardioplegic arrest induced by either warm or cold blood cardioplegia, and half to a control group, which did not receive L-arginine supplementation. RESULTS: Age, sex, and preoperative clinical status were similar in both groups. Seventeen patients of each group were administered intermittent warm antegrade blood cardioplegia, whereas the solution needed to be cooled to obtain complete standstill of the remaining eight hearts in each group. An internal thoracic artery graft to the left anterior descending coronary artery was performed in all patients. There was no death and no myocardial infarction in the treatment group, but there were one death and two infarctions in the control group. The amount of serial release of troponin I during the first 72 hours after the operation was similar between the L-arginine group and the control group (p > 0.05). Peak serum troponin levels averaged 4.9 +/- 1.0 microg/L in the arginine group and 3.9 +/- 1.0 microg/L in the control group (p > 0.05). A multivariate analysis of variance showed no effect of L-arginine (p > 0.05) but a significant effect of the temperature of the cardioplegic solution on the release of troponin I (p < 0.05). Serum troponin I levels averaged 2.2 +/- 0.4 microg/L, 4.5 +/- 0.4 microg/L, and 6.9 +/- 0.4 microg/L in the patients with cold cardioplegia and 1.4 +/- 0.3 microg/L, 2.4 +/- 0.3 microg/L, and 3.3 +/- 0.3 microg/L in the patients with warm cardioplegia 1, 2, and 6 hours, respectively, postoperatively. CONCLUSIONS: The administration of 1 g of L-arginine during the first 30 minutes of blood cardioplegic arrest did not result in a decrease in the postoperative release of cardiac enzyme; however, cold cardioplegic arrest significantly increased the release of cardiac troponin I postoperatively. There was no significant side effect related to the addition of L-arginine to the cardioplegic solution.

Arginine↗

In elective coronary artery bypass grafting, preoperative troponin T level predicts the risk of myocardial infarction.

OBJECTIVE: Several combinations of risk factors for death or cardiac events after coronary artery bypass grafting have been described. We studied the prognostic value of the preoperative serum levels of cardiac troponin T. METHODS: We studied 468 patients who underwent elective coronary artery bypass grafting. Preoperative and postoperative levels of cardiac troponin T and creatine kinase MB, electrocardiograms, clinical data, and events were recorded prospectively. No acute ischemic changes were present on the electrocardiogram before the operations, and preoperative creatine kinase MB serum levels were within normal limits in all patients. RESULTS: Ninety-seven (97/468, 21%) patients had serum levels of troponin T greater than 0.02 microg/L within 24 hours before coronary artery bypass grafting. Hospital mortality was similar in this group and in the patients with preoperative levels less than 0.02 microg/L (1% in each group). Nine patients (9/97, 9%) with elevated levels of troponin T before the operation had a perioperative myocardial infarction compared with 12 patients (12/371, 3%) among the group with lower troponin T levels (p = 0.015, RR = 2.9). Congestive heart failure occurred in 10 (10/97, 10%) and 8 (8/371,2%) patients, respectively (p = 0.0009, RR = 4.8). Intensive care unit (p = 0.002) and postoperative hospital length of stay (p = 0.09) were all longer in patients with the elevated preoperative troponin T level. In a logistic regression analysis, troponin T level before the operation was the variable most strongly correlated with postoperative myocardial infarction (p = 0.003). CONCLUSION: Preoperative troponin T stratification before coronary artery bypass grafting identifies a subgroup of patients with increased risk of postoperative cardiac complications.

Biomarkers↗

[Peri-operative benefits of beating-heart coronary revascularization in patients with triple vessel disease].

OBJECTIVES: To compare the perioperative benefits of the offpump coronary artery surgery to conventional surgery with cardiopulmonary bypass (CPB) assistance. METHOD: Retrospective study comparing 50 consecutive patients with triple vessel disease (TVD) operated upon with CPB assistance to 50 consecutive patients with TVD operated on beating heart (BH) by the same surgeon between January 1996 and August 1997 at the Montreal Heart Institute. Matching criteria between the 2 groups were: first time operation, normal left ventricular ejection function (LVEF), and coronary TVD. RESULTS: Demographic data and risk factors were comparable in both groups. Unstable angina was the most common surgical indication (CBP: 72%, BH: 62%). The average number of grafts were comparable in both groups (CBP: 3.5 vs 0.6 vs BH: 3.3 +/- 0.4, p = 0.06) as well as the preoperative LVEF (CEC: 60 +/- 1% vs CB: 62 +/- 1.2%, p = 0.38). Arterial lactate count was lower in the BH group during the perioperative period (3.0 +/- 1.0 vs 3.9 +/- 1.7 mM) as well as the maximal CK-MB level (BH: 20 +/- 6.4 vs CBP: 40 +/- 3.5 IU/L, p = 0.003), transfusional needs (CB: 34% vs CEC: 66%, p = 0.003), and postoperative creatinin level (BH: 100 +/- 4.2 vs CBP: 120 +/- 7.1 mM, p = 0.001). Postoperative HB level was also higher in the BH group (110 +/- 14 vs 104 +/- 12, p = 0.001). CONCLUSION: Our data confirm potential benefits from BH surgery on patients affected with triple vessel disease relatively to transfusional needs, and myocardial as well as renal protection.

Angina, Unstable↗

Evaluation of cost minimization strategies of anaesthetic drugs in a tertiary care hospital.

A survey was undertaken to compare anaesthetic drug expenditures over a three-year period, to evaluate the impact of strategies offered to curtain continuously rising drug costs. Suggestions to control rising expenditures were based primarily on education of staff and residents regarding drug costs, emphasizing rational use of the more expensive drugs, and minimizing drug wastage. To assess the impact of these measures, a review of annual hospital budgets, global pharmacy expenditures, and anaesthetic drug expenditures was conducted for the period 1991 to 1993. Both absolute and proportional costs of anaesthetic drugs were compared, by year, according to six major classes: opioid analgesics (OA), muscle relaxants (MR), inhalational anaesthetic drugs (INH), intravenous anaesthetic drugs (i.v.), local anaesthetic drugs (LA) and a category labelled other drugs (OTH). In addition, the utilization patterns and unit price changes were compared for each drug for the periods 1991-92, and 1992-93. Total hospital drug costs increased from $7.1 M to $8.5M over the three years. During the same period, the cost of anaesthetic drugs decreased from $379K to $361K, despite an augmentation in annual case load from 12,507 to 13,076 surgical procedures. For the entire survey period, the mean cumulative anaesthetic drug cost was 4.6% of the pharmacy budget, or 0.24% of the hospital budget. Analysis by drug class revealed a $51K decrease in expenditures on OA. due to decreased utilization of fentanyl and alfentanil, and a decrease in the price of fentanyl. The increased expenditure on INH drugs was primarily due to an increase in acquisition costs.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

The oral examination in anaesthetic resident evaluation.

Oral examinations have a traditional place in training and evaluation of professionals. Despite a lack of evidence identifying their value in assessment of candidates seeking anaesthetic specialty certification, oral examinations continue to be widely used. Although there is a considerable body of literature concerning oral examinations, there is no description of how this technique is employed in anaesthesia in Canada. The objective of this review is to provide faculty and residents with information concerning the strengths and weaknesses of this format, and the structure of the oral examination as practised in anaesthesia. Reliability of oral examinations can be affected by a number of factors dependent on the examiner, candidate, and the format. Properly constructed and prepared questions have well-defined characteristics. Components tested during the oral examination include: evaluation of a clinical situation, choice of therapy, medical knowledge, ability to deal with emergency situations, decision-making ability, and communication skills. When appropriately planned, the oral examination can be a useful component of the certification process.

Anesthesiology↗

Hypoxaemia created by pulmonary oedema after pulmonary microemboli in dogs.

Pulmonary microemboli may play a role in the adult respiratory distress syndrome, creating both pulmonary oedema and hypoxaemia. We measured the time course of pulmonary oedema and hypoxaemia after pulmonary microemboli of 63-74 mu starch were infused into dogs. Dogs were divided into two groups: six dogs that did not develop pulmonary oedema, and seven that did. Immediately after emboli there was no difference between groups in the large fall in PaO2 or the rise in Qs/Qt. Therefore the hypoxaemia of pulmonary embolism is not created by pulmonary oedema. As pulmonary oedema increased with time in the oedematous dogs, PaO2 fell further. There was no further reduction in PaO2 in the dogs who did not develop pulmonary oedema. We conclude that hypoxaemia after pulmonary embolism may be worsened if pulmonary oedema occurs, but the immediate large reduction in PaO2 after embolism is not created by pulmonary oedema.

Animals↗

Effect of purine nucleoside phosphorylase substrates on the mitogen-induced stimulation of murine T and B spleen cells.

The effect of culture with exogenous purine nucleoside phosphorylase substrates (especially deoxyguanosine) on the proliferation of mitogen-stimulated murine spleen cells was investigated. Con A-stimulated 3H-thymidine incorporation in unpurified and purified T cells was appreciably inhibited by culture in the presence of 100 microM deoxyguanosine. LPS-stimulated incorporation in unpurified and purified B cells was affected in a similar manner. Culture with guanosine inhibited incorporation in both mitogen-stimulated T and B cells to almost the same extent as deoxyguanosine. Inhibition of 3H-thymidine incorporation in T cells by deoxyguanosine was not modified by concomitant inclusion of deoxycytidine in the culture medium. In addition, deoxyguanosine had effects on T cell proliferative responses during the early phases of stimulation and even prior to stimulation with the mitogen. These results contrast with those reported for human lymphoid cells, where deoxyguanosine was much more potent that guanosine, and where only T cells were affected. They suggest that mechanisms other than the one involving inhibition of ribonucleotide reductase may also be important in the effects of deoxyguanosine on certain lymphoid cells.

Animals↗

Nitroglycerin relaxes large airways.

This study documents the effect of intravenous nitroglycerin (NTG) on tracheal smooth muscle in 12 patients undergoing coronary artery surgery. The pressure within a water-filled tracheal cuff was monitored continuously, as well as systemic and pulmonary arterial pressures. A significant decrease in cuff pressure after intravenous NTG (4.0 +/- 0.3 micrograms/kg) was detected before cardiopulmonary bypass (CPB). During CPB, with exclusion of the pulmonary arterial circulation, the tracheal cuff response to NTG administered into the oxygenator persisted and was not significantly different from that noted before CPB. Thus, the large airway (tracheal) response to NTG was independent of the pulmonary circulation and probably is mediated by the bronchial circulation. The response during CPB indicated that the tracheal smooth muscle retains tone and can respond to NTG even when the lungs are collapsed with no pulmonary arterial perfusion. These data were obtained from patients with no clinical evidence of reversible airway obstruction and indicate only that NTG relaxed human tracheal smooth muscle in vivo. These data do not demonstrate the efficacy of intravenous NTG in patients with asthma.

Adult↗