Deeb Zabeeda

Comparison of systemic vasodilators: effects on flow in internal mammary and radial arteries

BACKGROUND Spasm is a major concern with the use of arterial conduits in coronary artery bypass surgery (CABG). We evaluated the effect of systemic vasodilators on in vivo radial artery flow compared with internal mammary artery (IMA) flow. METHODS Fifty patients undergoing primary CABG with a mean age of 69 +/- 5 years enrolled in this study and were randomized to 1 of 5 groups based on the vasodilating agent administered (nitroglycerin, nitroprusside, dobutamine, milrinone, and normal saline as control group). Radial artery and IMA flows, blood pressure, central venous pressure, and heart rate were measured before and 10 minutes after drug administration. RESULTS Mean arterial pressure decreased significantly after drug administration in both the nitroglycerin (p = 0.007) and nitroprusside (p < 0.001) groups and increased in the dobutamine group (p < 0.001). There were no significant differences between IMA flow or radial flow among the groups before drug administration. A multivariate general linear model was created and revealed drug (specifically nitroglycerin) as the only predictor to increase flow in the IMA (p < 0.001) or the radial artery (p = 0.009). CONCLUSIONS We conclude that intravenous nitroglycerin causes in vivo vasodilatation of both the IMA and radial artery and is a good systemic vasodilator to be given when harvesting these two conduits.

Save a child’s heart: we can and we should

BACKGROUND Congenital heart disease (CHD) causes the death of thousands of children in developing countries. At the Wolfson Medical Center (WMC), a prototype program has been developed to address this issue. METHODS Since 1996, indigent children have been referred to the program, with the cooperation of partners in developing countries. The projects aims are to (a) train their medical personnel at WMC, (b) travel to participating countries to teach, evaluate patients, operate, and promote the development of local centers, and (c) treat children with CHD, at WMC, who lack a local option for care either due to prohibitive costs or unavailability. The projects personnel are state employees who volunteer to treat additional patients within the framework of their salaries, and community volunteers. RESULTS The program has seven partner sites in six countries, including two provinces in China (Hebei and Gansu), Ethiopia, Moldova, Nigeria, the Palestinian Authority, and Tanzania. Five physicians and 10 nurses have been trained from five participating countries. Over the past 4 years, 11 teaching trips have been made abroad, and operations have been performed at four partner sites. A total of 386 patients have been operated on-360 at WMC and 26 at other sites. There have been 17 (4.3%) acute deaths. Follow-up is 92% complete with 3 late deaths reported. CONCLUSIONS Hospital-based regional centers can be created to promote the care of children with CHD in developing countries. Good results and follow-up care can be provided with appropriate planning.

Tranexamic acid reduces bleeding and the need for blood transfusion in primary myocardial revascularization.

BACKGROUND The objective of this study was to study the effect of low-dose tranexamic acid (TA) on postoperative bleeding and coagulation variables after coronary artery bypass grafting operation. METHODS Fifty patients undergoing primary coronary artery bypass grafting were randomly assigned to receive either placebo (0.9% NaCl; n = 25) or 10 mg/kg TA followed by infusion of 1 mg/kg per hour during the operation (n = 25). Data measured included blood loss, transfusion, reoperation, fibrinogen level, fibrinogen split products, platelet size, and platelet function. Measurements were made after induction of anesthesia, after heparin administration, during patient warming, after skin closure, and 24 hours after operation. RESULTS Patients in the TA study group weighed less. Other demographic characteristics were similar between groups. Postoperative bleeding was less in the TA group (194 +/- 135 mL versus 488 +/- 238 mL, p < 0.001), whereas blood requirement was higher in the control group (1.68 +/- 1 versus 0.52 +/- 0.9 U of packed cells per patient, p < 0.001). The percent of patients exposed to blood products was significantly less in the TA group (36% versus 100%, p < 0.001). Fibrinogen split products were lower in the TA group during bypass (p < 0.001). Fibrinogen levels fell in both groups during cardiopulmonary bypass. Platelet number and function were reduced equally in both groups by cardiopulmonary bypass. Other test results were not different between groups. CONCLUSIONS The use of low-dose TA during coronary artery bypass grafting significantly reduced the coagulopathy-induced postoperative bleeding and allogeneic blood products requirement. The low levels of fibrinogen split products during bypass in the study group reflect the inhibiting effect of TA in fibrinolysis. Tranexamic acid had no effect on platelet function during cardiopulmonary bypass.

Difficult laryngoscopy: incidence and predictors in patients undergoing coronary artery bypass surgery versus general surgery patients.

OBJECTIVE Cardiac surgery patients might have a higher incidence of difficult laryngoscopy than the general population because of older age, dental problems, and obesity. The authors estimated the incidence and predictors of difficult laryngoscopy in coronary artery bypass surgery patients. DESIGN Prospective, controlled study. SETTING University setting. PARTICIPANTS Patients undergoing coronary artery bypass or general surgery. INTERVENTIONS Two hundred consecutive patients undergoing coronary artery bypass graft and 444 general surgery patients, all aged >40 years, were compared for the incidence and predictors of difficult laryngoscopy, defined as a grade III or IV view. MEASUREMENTS AND MAIN RESULTS Predictors of difficult laryngoscopy were considered mouth opening <4 cm, limited cervical mobility, thyromental distance <6 cm, protruding or partially missing upper teeth, and Mallampati classes 3 and 4. More cases of difficult laryngoscopy were recorded in cardiac patients (10% v 5.2%, p <0.023). The cardiac patients were older, mostly men, and belonged to ASA III-IV risk classes. Mallampati classes 3 and 4 were more frequent in the control group. With univariate analysis, difficult laryngoscopy correlated with 7 variables: older age, ASA-IV risk class, protruding or partially missing upper teeth, limited mouth opening, limited neck movement, thyromental distance <6 cm, and diabetes mellitus. Multivariate analysis adjusted for propensity score identified older age (odds ratio = 1.05/yr, 95% confidence interval = 1.005-1.09, p < 0.03) and limited neck movement (odds ratio = 9.5, 95% confidence interval = 2.2-41, p < 0.003), but not cardiac surgery per se, as independent predictors of difficult laryngoscopy. CONCLUSIONS Difficult laryngoscopy was more frequent in cardiac surgery patients (10% v 5.2%). Older age and limited neck movement, but not cardiac surgery per se, were independent predictors of difficult laryngoscopy.

Effect of Systemic Vasodilators on Internal Mammary Flow During Coronary Bypass Grafting

BACKGROUND The effect of vasodilators on acute flow in the internal mammary (IMA) is unclear. Topical vasodilators show no effect on acute flow when the distal segment of the IMA is resected. The purpose of this study was to evaluate the effect of systemic vasodilators when this segment is resected. METHODS We studied 60 patients with proximal anterior descending coronary artery lesions in whom the left IMA was harvested for grafting to the left anterior descending coronary artery. The patients were divided into six groups (n = 10), based on which of the following agents were studied: normal saline solution, nitroglycerin, nitroprusside, dobutamine, dopexamine, and amrinone. After harvesting, the IMA was trimmed as proximally as possible (and at least 3 cm proximal to the bifurcation), and free flow was measured before any pharmacologic intervention (flow 1). Systemic infusion of one of the six agents commenced. A mean of 17 +/- 3.4 minutes after infusion began, with a comparable cardiac index, a second measurement of IMA flow was taken (flow 2). Hemodynamic measurements for each flow, including blood pressure, heart rate, and cardiac output, were taken. RESULTS A significant increase in IMA flow was noted for those patients receiving nitroglycerin (93.5 versus 106.8 mL/min; p = 0.025), and a significant decrease in flow was noted for those receiving nitroprusside (91.0 versus 78.2 mL/min; p = 0.042). The effects remained significant when corrected for cardiac index and compared with the normal saline solution group. No other systemic agents tested significantly affected the IMA flow (dobutamine, 83.8 versus 85.0 mL/min; dopexamine, 101.8 versus 91.4 mL/min; amrinone, 75.4 versus 79 mL/min; normal saline solution, 85.8 versus 84.6 mL/min). CONCLUSIONS Resection of the distal segment of the IMA and the use of intravenous nitroglycerin optimizes the flow in IMA grafts.

Similar incidence of hypotension with combined spinal-epidural or epidural alone for knee arthroplasty.

Objectif Nous avons emis ľhypothese que ľincidence ďhypotension pendant ľarthroplastie totale du genou (ATG) serait plus faible avec ľanesthesie rachidienne et peridurale combinee (RPC) qu’avec ľanesthesie peridurale seule.BackgroundWe hypothesized that the incidence of hypotension during total knee replacement (TKR) surgery is lower in patients given combined spinal-epidural (CSE) anesthesia vs those receiving epidural anesthesia alone.MethodsIn a prospective study, 80 American Society of Anesthesiologists I–II patients (aged 40–80 yr), undergoing elective TKR surgery were randomly assigned to either CSE anesthesia (CSE,n = 40) or epidural anesthesia alone (Epidural,n = 40). Hemodynamic measurements included oscillometric mean arterial blood pressure (MAP), heart rate (HR), and cardiac index (CI) as determined by thoracic bioimpedance; systemic vascular resistance (SVR) was calculated. Our primary endpoint (outcome) was the number of hypotension episodes (defined as MAP < 70 mmHg).ResultsUsing univariate analysis, we found no differences between the groups in regards to MAP, HR, CI, or SVR during the perioperative period. The incidence of hypotension was similar in both groups (two patients in each group), as was the incidence of bradycardia (12 patients in CSE, 7 in Epidural;P = 0.2). There were no differences between groups in other hemodynamic measurements including CI and calculated SVR. Analgesia supplementation with fentanyl was more frequently required in the Epidural group (20 vs 6 patients —P = 0.03).ConclusionCombined spinal-epidural anesthesia and epidural anesthesia alone during TKR surgery are associated with the same incidence of hypotension with statistically and clinically similar hemodynamic responses.RésuméObjectifNous avons émis ľhypothèse que ľincidence ďhypotension pendant ľarthroplastie totale du genou (ATG) serait plus faible avec ľanesthésie rachidienne et péridurale combinée (RPC) qu’avec ľanesthésie péridurale seule.MéthodeLors ďune étude prospective, 80 patients ďétat physique ASA I–II, de 40 à 80 ans, subissant une ATG réglée, ont été répartis aléatoirement pour recevoir une anesthésie RPC (groupe RPC, n = 40) ou péridurale seule (groupe péridural,n = 40). Les mesures hémodynamiques comprenaient la tension artérielle moyenne (TAM) oscillométrique, la fréquence cardiaque (FC) et ľindex cardiaque (IC) déterminé par la bio-impédance thoracique; la résistance vasculaire générale (RVG) a été calculée. Notre principal paramètre était le nombre ďépisodes ďhypotension définie par une TAM < 70 mmHg).RésultatsSelon une analyse univariée, il n’y avait aucune différence intergroupe quant à la TAM, la FC, ľIC ou la RVG périopératoires. Ľincidence ďhypotension était similaire dans les deux groupes (deux dans chaque groupe), aussi ľincidence de bradycardie (12 avec ľanesthésie RPC et 7 avec la péridurale; P = 0,2). Les autres mesures hémodynamiques ne présentaient pas de différence intergroupe, y compris ĽIC et la RVG calculée. Un supplément ďanalgésie avec du fentanyl a été plus souvent requis dans le groupe péridural (20 vs 6 patients — P = 0,03).ConclusionĽanesthésie rachidienne et péridurale combinée et ľanesthésie péridurale seule, utilisées pendant ľATG, sont associées à la même incidence ďhypotension et à des réactions hémodynamiques similaires au plan statistique et clinique.

Changes in platelet function, volume and count during labor and 24 hours postpartum

Increased platelet activation has been reported during labor. We evaluated changes in platelet count, volume and function during labor and 24 hours postpartum. Platelet function during labor was not previously evaluated. Twenty-five healthy women in labor, subsequently having singleton spontaneous vaginal delivery following uncomplicated pregnancy at term were recruited for this prospective study. Blood was withdrawn during latent phase, active phase, second stage of labor, and 24 hours postpartum. Platelet function was assessed by hemoSTATUS2 test (Hepcon®, Medtronic, USA). Twenty-five healthy non-pregnant volunteers served as controls. Platelet count and volume did not change significantly throughout labor and 24 hours postpartum. Platelet function was 120.8 ± 26.9 %, 106.8 ± 24.6 % (p = 0.06), 105.2 ± 30.9 % (p < 0.05), and 117.6 ± 21.5 % during latent phase, active phase, second stage of labor, and 24 hours postpartum, respectively. Platelet function was altered during labor while platelet count and volume did not change significantly. Platelet function remained increased when compared to non-pregnant controls.

Ľanesthésie rachidienne et péridurale combinée, et péridurale seule, ont une incidence similaire ďhypotension lors de ľarthroplastie du genou

Objectif Nous avons emis ľhypothese que ľincidence ďhypotension pendant ľarthroplastie totale du genou (ATG) serait plus faible avec ľanesthesie rachidienne et peridurale combinee (RPC) qu’avec ľanesthesie peridurale seule.BackgroundWe hypothesized that the incidence of hypotension during total knee replacement (TKR) surgery is lower in patients given combined spinal-epidural (CSE) anesthesia vs those receiving epidural anesthesia alone.MethodsIn a prospective study, 80 American Society of Anesthesiologists I–II patients (aged 40–80 yr), undergoing elective TKR surgery were randomly assigned to either CSE anesthesia (CSE,n = 40) or epidural anesthesia alone (Epidural,n = 40). Hemodynamic measurements included oscillometric mean arterial blood pressure (MAP), heart rate (HR), and cardiac index (CI) as determined by thoracic bioimpedance; systemic vascular resistance (SVR) was calculated. Our primary endpoint (outcome) was the number of hypotension episodes (defined as MAP < 70 mmHg).ResultsUsing univariate analysis, we found no differences between the groups in regards to MAP, HR, CI, or SVR during the perioperative period. The incidence of hypotension was similar in both groups (two patients in each group), as was the incidence of bradycardia (12 patients in CSE, 7 in Epidural;P = 0.2). There were no differences between groups in other hemodynamic measurements including CI and calculated SVR. Analgesia supplementation with fentanyl was more frequently required in the Epidural group (20 vs 6 patients —P = 0.03).ConclusionCombined spinal-epidural anesthesia and epidural anesthesia alone during TKR surgery are associated with the same incidence of hypotension with statistically and clinically similar hemodynamic responses.RésuméObjectifNous avons émis ľhypothèse que ľincidence ďhypotension pendant ľarthroplastie totale du genou (ATG) serait plus faible avec ľanesthésie rachidienne et péridurale combinée (RPC) qu’avec ľanesthésie péridurale seule.MéthodeLors ďune étude prospective, 80 patients ďétat physique ASA I–II, de 40 à 80 ans, subissant une ATG réglée, ont été répartis aléatoirement pour recevoir une anesthésie RPC (groupe RPC, n = 40) ou péridurale seule (groupe péridural,n = 40). Les mesures hémodynamiques comprenaient la tension artérielle moyenne (TAM) oscillométrique, la fréquence cardiaque (FC) et ľindex cardiaque (IC) déterminé par la bio-impédance thoracique; la résistance vasculaire générale (RVG) a été calculée. Notre principal paramètre était le nombre ďépisodes ďhypotension définie par une TAM < 70 mmHg).RésultatsSelon une analyse univariée, il n’y avait aucune différence intergroupe quant à la TAM, la FC, ľIC ou la RVG périopératoires. Ľincidence ďhypotension était similaire dans les deux groupes (deux dans chaque groupe), aussi ľincidence de bradycardie (12 avec ľanesthésie RPC et 7 avec la péridurale; P = 0,2). Les autres mesures hémodynamiques ne présentaient pas de différence intergroupe, y compris ĽIC et la RVG calculée. Un supplément ďanalgésie avec du fentanyl a été plus souvent requis dans le groupe péridural (20 vs 6 patients — P = 0,03).ConclusionĽanesthésie rachidienne et péridurale combinée et ľanesthésie péridurale seule, utilisées pendant ľATG, sont associées à la même incidence ďhypotension et à des réactions hémodynamiques similaires au plan statistique et clinique.