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Biomedical subjects

E Ovrum

Publications and source records attributed to E Ovrum.

At least 37 records · Page 2Linked to original sources
PubMed1995

Conversion of postischemic ventricular fibrillation with intraaortic infusion of potassium chloride.

BACKGROUND: Ventricular fibrillation after declamping of the aorta after cardioplegic arrest is commonly managed by direct-current countershock. However, in coronary artery bypass grafting, placement of the electrodes can cause mechanical damage to the grafts and anastomoses, and the surgical procedure must be interrupted. As an alternative, intraaortic infusion of potassium chloride through the arterial line from the heart-lung machine was investigated. METHODS: In a series of 100 patients with postischemic ventricular fibrillation (group P), 20 mmol of potassium chloride (plus 10 mmol later if necessary) was added to the oxygenator reservoir and perfused through the arterial line into the proximal aorta. The results were compared with those in a matched control group of 100 patients primarily treated with direct-current countershock (group DC). RESULTS: In group P, the ventricular fibrillation was effectively converted to a supraventricular rhythm in 82% of the patients. The remaining 18 patients required significantly (p < 0.005) fewer electric shocks than the patients in group DC. Serum K+ levels were slightly elevated for a short period after the potassium chloride infusion. Otherwise there were no significant differences in regard to incidence of heart block, temporary epicardial pacing, myocardial infarction, or atrial fibrillation between the two groups. CONCLUSIONS: Conversion of postischemic ventricular fibrillation with potassium chloride administered through the arterial line from the heart-lung machine is an effective, gentle, and convenient method. No side effects were noted.

Adult↗
PubMed1995

Complement and granulocyte activation in two different types of heparinized extracorporeal circuits.

Complement and granulocyte activation were studied in cardiopulmonary bypass circuits completely coated with either end-attached covalent-bonded heparin, the Carmeda BioActive Surface, or with the Duraflo II bonded heparin, in combination with reduced systemic heparinization (activated clotting time > 250 seconds). The control groups were perfused with uncoated circuits and full heparin dose (activated clotting time > 480 seconds). Altogether 67 patients undergoing elective first-time myocardial revascularization were investigated, having extracorporeal perfusion with a Duraflo II coated circuit (n = 17), an identical but uncoated circuit (n = 17), a Carmeda coated circuit (n = 17), or an equivalent uncoated circuit (n = 16). During cardiopulmonary bypass, the C3 activation products C3b, iC3b, and C3c (C3bc) and the terminal SC5b-9 complemented complex increased markedly in all four groups compared with baseline, but significantly less in the two coated groups than in their control groups. Additionally, a significantly lower concentration of C3bc was observed in the Carmeda coated group, with maximal increase of median 28 AU/ml compared with 50 AU/ml in the Duraflo II coated group (p = 0.003). Similarly, in the Carmeda coated group, the maximal increase of terminal complement complex was considerably lower (0.8 AU/ml) than the levels recognized in the Duraflo II coated group (2.4 AU/ml) (p < 0.001). The release of the granulocyte activation myeloperoxidase and lactoferrin increased from the beginning of the operation, with peak levels at the end of bypass. A significant reduction of lactoferrin release was recognized when comparing the coated groups with the control groups. The difference between the two coated groups (Carmeda 228 micrograms/L; Duraflo II 332 micrograms/L; p = 0.05) was marginally significant. For myeloperoxidase, no significant differences were observed between the coated and uncoated groups. In conclusion, both types of heparin-coated circuits reduced complement activation and release of lactoferrin, but the Carmeda circuit proved to be more effective than the Duraflo II equipment.

Aged↗
PubMed1995

Consistent non-pharmacologic blood conservation in primary and reoperative coronary artery bypass grafting.

Because much interest has been focused on blood conservation using different drugs and complicated blood cell processing devices, we analyzed our results with the use of a non-pharmacologic, simple and inexpensive program for blood salvage in 2326 patients undergoing myocardial revascularization. The material was divided into two groups: patients undergoing a primary coronary bypass operation (Group P, n = 2298) and a smaller subset of patients undergoing repeat coronary bypass operation (Group R, n = 28). At least one internal mammary artery was grafted in 99% of the patients, with supplemental saphenous vein grafts. Intraoperatively, autologous heparinized blood was removed before bypass and retransfused at the conclusion of extracorporeal circulation. The volume remaining in the extracorporeal circuit was returned without cell processing or hemofiltration. Autotransfusion of the shed mediastinal blood was continued hourly up to 18 h after surgery in all patients. The mean postoperative mediastinal drainage in group R was 543 +/- 218 ml, compared to 703 +/- 340 ml in Group P (P = 0.01). In Group R, 1 patient (3.6%) received packed red cells and no patients were given other homologous blood products, compared to 33 patients (1.4%) given red cells and 35 patients (1.5%) given plasma transfusion in Group P (NS). Thus, in total, 2257 patients (97.0%) were not exposed to any homologous blood products during hospitalization. Total hemoglobin loss was significantly higher in Group R, resulting in a mean hemoglobin concentration at discharge of 109 +/- 13 g/l, compared to 121 +/- 14 g/l in Group P (P = 0.0002).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Pyoderma gangrenosum as a complication of coronary artery bypass grafting.

A 60-year-old male patient developed progressive wound ulcerations, simulating wound sepsis after coronary bypass operation. The condition did not respond to intensive antibiotic therapy. Based on clinical signs and biopsy, the diagnosis of pyoderma gangrenosum was made and successfully treated with cyclosporin A. Pyoderma gangrenosum, although extremely rare, must be considered as a possible diagnosis in wound complications unresponsive to traditional therapy.

Angina Pectoris↗
PubMed1993

Tranexamic acid (Cyklokapron) is not necessary to reduce blood loss after coronary artery bypass operations.

The contribution of fibrinolysis to postoperative bleeding after cardiopulmonary bypass led to routine use of tranexamic acid, a potent antifibrinolytic drug, for a period of time. Two hundred patients undergoing elective coronary artery bypass operations were studied, one group of 100 patients given tranexamic acid (40 mg/kg) (group I) after bypass and one subsequent group of 100 patients (group II) serving as a control group. All patients were treated by the same team, and the groups were comparable in all major clinical parameters. The mean mediastinal drainage in group I was 565 +/- 239 ml versus 656 +/- 257 ml in group II. Univariate and multivariate analysis revealed statistical significance (p = 0.02) when corrected for body surface area. However, applying a consistent blood conservation protocol, including removal of autologous blood before bypass for retransfusion after bypass, returning of all oxygenator and tubing contents to the patients, and autotransfusion of the mediastinal shed blood up to 18 hours postoperatively, resulted in nearly identical hemoglobin concentration at discharge (119 +/- 14 gm/L in group I and 121 +/- 14 gm/L in group II). The prevalence of postoperative myocardial infarction included five patients in group I compared with one patient in group II. Although not statistically significant (p = 0.2), the difference is of concern. Tranexamic acid has a beneficial effect on reducing postoperative bleeding after coronary artery bypass operations. The routine use of the drug is not recommended, however, because its effect is a weak one, and it may be of potential hazard by precipitating thrombosis and eventual myocardial infarction.

Adult↗
PubMed1992

Hemodynamic evaluation of the CarboMedics prosthetic heart valve in the aortic position: comparison of noninvasive and invasive techniques.

Seventy-three patients with a CarboMedics aortic bileaflet valve prosthesis were examined by Doppler ultrasonography, and 27 of them were also assessed by transseptal catheterization. The ultrasonic mean systolic gradient was 17.1 +/- 5.6 mm Hg for valve size 19 mm, falling gradually with increasing valve size to 6.8 +/- 2.5 mm Hg for size 27 mm. The catheter mean systolic gradient was consistently smaller than the ultrasonic gradient (4.3 +/- 4.8 mm Hg), but Tobit regression analysis showed a significant association between the two methods. In all patients both methods revealed negligible to small amounts of retrograde leakage, which is assumed to be a normal finding for this valve. The effective flow areas of the valves calculated from the ultrasonic data were similar to the in vitro calculated flow areas. The hemodynamic potential of this valve is therefore completely utilized in vivo. The effective orifice area corrected for body surface area increased with increasing valve size, which demonstrates a moderate valve-patient mismatch.

Adult↗
PubMed1992

Hemodynamic effects of intraaortic versus intravenous protamine administration after cardiopulmonary bypass in man.

A hemodynamic study of men undergoing elective coronary artery bypass surgery was undertaken to elucidate the side effects of protamine given into the ascending aorta (group A, n = 16) or into the central venous line (group V, n = 16). After termination of extracorporeal circulation, protamine was infused over 120 seconds, and the hemodynamic profile was continuously recorded. During the first minute, the systemic arterial pressure fell to about 60% of the preprotamine level in both groups, but the hemodynamic changes occurred more rapidly (p < 0.05) in group V than in group A, with maximal pressure drop at 61.7 +/- 2.7 vs 74.4 +/- 4.9 seconds. Following spontaneous restoration of the systemic blood pressure, the pulmonary artery pressure rose considerably in both groups, as did the pulmonary capillary wedge and central venous pressures, reaching higher levels in the intravenous group. The cardiovascular responses were again more rapid in group V than in group A (p = 0.004). The degree of systemic hypotension thus did not benefit from use of the intraaortic rather than the intravenous route for administering protamine. The more pronounced and more rapid pulmonary circulatory changes in the intravenous group suggest that the hemodynamic effects of protamine are initiated in the lungs.

Aorta↗
PubMed1991

[How hazardous is elective coronary bypass surgery? Perioperative course in 1000 consecutive patients].

During a 30 month period, 1,000 consecutive elective coronary artery bypass operations were performed in 863 men and 137 women. The majority of the patients had no impairment of the left ventricle; more than 66%, however, had one or more operative high risk factors (old age, female sex, low ejection fraction, diabetes, overweight, unstable angina). Perioperative complications, which included prolonged stay in hospital, were noted in 24 patients (2.4%), due to myocardial infarction, wound infection or neurological disorder. Myocardial necrosis, diagnosed by new Q-waves and elevated enzymes, was demonstrated in 31 patients (3.1%), most of whom were asymptomatic. A consistent blood conservation programme resulted in avoidance of any homologous blood products in 96.4% of the patients. The mortality among hospitalized patients was 1/1,000 (0.1%). Elective coronary artery bypass surgery may be performed with a very low rate of mortality and morbidity, which compares very well with the results achieved after alternative revascularization procedures such as percutaneous transluminal coronary angioplasty (PTCA), laser angioplasty and arterectomy.

Aged↗
PubMed1991

Conventional blood conservation techniques in 500 consecutive coronary artery bypass operations.

With use of a nonpharmacological, simple, and inexpensive program for blood conservation, 500 consecutive patients underwent elective coronary artery bypass grafting without need of homologous red cell transfusions in 493 (98.6%). At least one internal mammary artery was grafted in all but 1 patient, with supplemental saphenous vein grafts. Intraoperatively, autologous heparinized blood was removed before bypass and retransfused at the conclusion of extracorporeal circulation. The volume remaining in the oxygenator and tubing set was returned without cell processing or hemofiltration. Using the hard-shell cardiotomy reservoir from the heart-lung machine, autotransfusion of the shed mediastinal blood was continued hourly up to 18 hours after operation. The mean postoperative mediastinal blood loss was 643 +/- 354 mL, whereas 624 +/- 296 mL was autotransfused. Thirteen patients (2.6%) needed reexploration for bleeding, of whom 7 (7/500, 1.4%) received homologous blood. No other patients required red cell transfusions. In addition, 9 patients were given a mean of 2.6 units of fresh frozen plasma because of suspected coagulopathy. No platelets were transfused, and no cryoprecipitate therapy was undertaken. Thus, in total, 484 patients (96.8%) were not exposed to any homologous blood products during the hospital stay. At discharge, the mean hemoglobin concentration was 121 +/- 14 g/L (12.1 +/- 1.4 g/dL) and the hematocrit, 0.36 +/- 0.04. Postoperative complications were few. There was one in-hospital death (0.2%).

Adult↗
PubMed1991

Autotransfusion after open heart surgery: characteristics of shed mediastinal blood and its influence on the plasma proteases in circulating blood.

Fourteen patients undergoing open-heart surgery received intermittent or continuous postoperative autotransfusion of shed mediastinal blood (minimum 400 ml during 6 h after surgery) collected in the cardiotomy reservoir. Hematologic variables and changes in the coagulation, fibrinolytic and plasma kallikrein-kinin systems were investigated in the reservoir blood at the beginning and after 6 h of autotransfusion, and in patient blood during and after surgery and before and after autotransfusion. Autotransfusion volume ranged from 400 to 1200 ml per patient (median 482 ml). The reservoir blood had a median haemoglobin level of 93 and 74 g/l, a platelet count of 71 and 119 x 10(9)/l, and plasma haemoglobin level of 3110 and 4100 mg/l before and after 6 h of autotransfusion, respectively. Further examination of the reservoir blood showed that it had undergone extensive coagulation and fibrinolysis as well as a moderate activation of the kallikrein-kinin system. Despite these extensive alterations in the reservoir blood, no major change could be found in the circulating blood after autotransfusion, except for a moderate increase in plasma haemoglobin from 180 mg/l to 430 mg/l. The clinical safety and simplicity of this technique were confirmed for autotransfusion of shed mediastinal blood up to 1200 ml.

Aged↗
PubMed1991

Elective coronary artery bypass surgery without homologous blood transfusion. Early results with an inexpensive blood conservation program.

Restriction of donor blood transfusions in cardiac surgery should reduce risks of infective contamination and antigenicity. We report a systemic, simple and inexpensive blood conservation program used for 121 consecutive patients who underwent elective coronary artery bypass surgery without need for homologous blood transfusion. The left internal mammary artery was grafted in all cases, in addition to saphenous vein grafts. Autologous, heparinized blood was removed intraoperatively, pre-bypass, and returned to the patient at conclusion of the extracorporeal circulation. The volume remaining in the oxygenator and the tubing set was returned without cell processing or hemofiltration. Using the hard-shell cardiotomy reservoir from the heart-lung machine, autotransfusion of the shed mediastinal blood was continued hourly up to 18 hours after surgery. The mean postoperative mediastinal bleeding was 551 +/- 206 ml, of which 505 +/- 218 ml was autotransfused. No re-exploration for bleeding was required and no homologous red-cell transfusions were given. Five patients each received 1-2 units of fresh frozen plasma because of prolonged bleeding time. Morbidity was low and mortality nil. At discharge the mean hemoglobin was 12.0 +/- 1.4 g/dl and the hematocrit 36.0 +/- 4.2%.

Adult↗
PubMed1991

Systemic and pulmonary circulatory effects of protamine following cardiopulmonary bypass in man.

The cardiovascular effects of protamine were studied in 19 men with normal left ventricular function undergoing primary myocardial revascularization. Protamine was given over 120 sec after termination of cardiopulmonary bypass. Arterial and pulmonary pressures, aortic blood flow, central venous pressure, heart rate and electrocardiogram were continuously registered. Pulmonary capillary wedge pressure was recorded at the times of maximal hemodynamic response. The systolic arterial pressure fell from 116 to 66 mmHg about 60 sec after the start of protamine infusion, but spontaneously began to rise after a few seconds, reaching 90% of pre-protamine levels at 126 sec. No inotropic drugs or volume infusion were given. At about 2 min, the mean pulmonary artery pressure rose from 16.3 to 26.2 mmHg and the central venous pressure from 7.0 to 11.4 mmHg. The heart rate and cardiac output were almost unchanged throughout. Systemic hypotension and pulmonary hypertension are suggested to represent true side effects of protamine or protamine/heparin complex. When left ventricular function is good, the hypotension reverses without treatment. Volume infusion may indeed precipitate right heart failure when the pre-load effect is added to the subsequent protamine-induced pulmonary hypertension.

Cardiopulmonary Bypass↗
PubMed1990

[Heart surgery without blood transfusion].

Blood conservation in open heart surgery has become mandatory in order to reduce the risk of viral contamination, and because of limited resources. We have performed 100 consecutive coronary artery bypass operations (13 women/87 men, aged 33-73 years, mean 58 years) without using homologous blood. A strict blood conservation programme was applied, with removal of autologous blood prebypass for retransfusion at the end of surgery, retransfusion of the heart-lung machine content to the patient, and autotransfusion of shed mediastinal blood in the postoperative period. All patients survived the operation and were extubated 1.6 hours (0-6) postoperatively. No patients needed resternotomy for bleeding, and no homologous blood was given. Five patients received 1-2 units of fresh frozen plasma because of coagulopathy. Mean hemoglobin was 12.0 g/100 ml and mean hematocrit was 36% at discharge from hospital. Elective coronary artery bypass surgery can be performed with little or no transfusions of homologous blood.

Adult↗
PubMed1990

Coronary artery bypass surgery with minimal use of homologous blood. Effects of a simple and inexpensive blood conservation programme.

Restriction of donor blood transfusions in cardiac surgery should decrease the risk of infective contamination and antigenicity. Following a simple, systematic and inexpensive blood conservation program, we report on 250 consecutive patients undergoing elective coronary artery bypass surgery, 247 (98.6%) of whom did not need homologous blood transfusions. At least one internal mammary artery was grafted in all but one patient, in combination with saphenous vein grafts. Intraoperatively, autologous heparinized blood was removed before bypass and retransfused at the conclusion of extracorporeal circulation. The remaining volume of the oxygenator and tubing set was retransfused without any cell processing or hemofiltration. Using the hard-shell cardiotomy reservoir from the heart lung machine, autotransfusion of the shed mediastinal blood was continued hourly up to 18 h after surgery. The mean postoperative mediastinal bleeding was 622 +/- 287 ml, of which 589 +/- 296 ml was autotransfused. Five patients (2.0%) needed re-exploration for bleeding, and three of these received 1-4 units of homologous blood. No other patients needed red cell transfusions. Seven patients were given a mean of 2.6 units of fresh frozen plasma because of coagulopathy. Thus, altogether 240 patients (96%) were not exposed to any homologous blood products during their hospital stay. Morbidity was low. At discharge, the mean hemoglobin concentration was 12.0 +/- 1.4 g/dl and the mean hematocrit 36.0 +/- 4.2%. There were no deaths.

Adult↗
PubMed1989

Experiences with closed chest, temporary atrio-arterial, ventricular bypass with a centrifugal pump after open heart surgery.

Twelve patients with refractory myocardial failure following open heart surgery were treated with a temporary left (10), right (1) or biventricular (1) assist circuits driven by extracorporeal pumps. Ten of 11 patients were weaned from the pump oxygenator. During left ventricular assist, maximal pump flow was 2.2 +/- 0.6 l/min per m2 at a cardiac index of 2.5 +/- 0.9 l/min per m2. Diuresis was above 1 ml/kg body weight per h in 7 of 9 patients perfused for 13-36 h. Seven patients were weaned from the assist pump after 13-33 h of ventricular bypass with 4 hospital survivors. Two patients died after circulatory assistance of multiple organ failure, 1 from cerebral damage. In the other patients, the main problems were cardiac. Three patients are currently long term survivors 12-17 months after surgery.

Cardiopulmonary Bypass↗
PubMed1989

Colloid versus crystalloid cardioplegia. A prospective, randomized clinical study.

The effects of adding colloid (dextran 40, Rheomacrodex) to cardioplegic solution were studied in 55 men undergoing bypass grafting for uncomplicated coronary artery disease. The patients were randomly allocated to group I (n = 27), in which 35 g dextran 40 was added to the St Thomas II cardioplegic solution, or group II (n = 28), which received a standard crystalloid cardioplegic solution. The groups were comparable in regard to preoperative and intraoperative data. In group I the pulmonary vascular resistance index was transiently elevated after extracorporeal circulation and both oxygen consumption and arteriovenous oxygen content difference 2 hours postoperatively were greater than in group II, suggesting better microcirculation. Postoperative normalization of the chest X-rays was more rapid in group I. The clinical course was similar in the two groups.

Cardioplegic Solutions↗