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Biomedical subjects

E Ovrum

Publications and source records attributed to E Ovrum.

At least 19 recordsLinked to original sources
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↗
PubMed1989

Is cold, cardioplegic solution harmful to the lungs?

The effects of pulmonary flush with cold cardioplegic solution were investigated in 55 patients undergoing coronary artery bypass grafting. Extracorporeal circulation with bicaval cannulation was used in all cases, and single-dose cardioplegic solution was injected into the aortic root. In one of two randomly selected groups (n = 27) the cardioplegic solution was allowed to pass through the lungs and then evacuated via a left ventricular vent. In a second group (n = 28) the vent was first temporarily placed in the right atrium for evacuation of the cardioplegic solution, and the aortic root was vented later. Hemodynamic, metabolic, hematologic and radiographic changes were studied during the early postoperative period. No harmful effects of the pulmonary passage could be demonstrated. On the contrary, a protective effect was indicated, as the pulmonary vascular resistance index was reduced immediately and for 2 hours postoperatively. The ratio of left ventricular to right ventricular stroke work in the early postoperative period gave the same indication.

Cardioplegic Solutions↗
PubMed1988

Risk factors in surgically treated mitral valve disease.

Risk factors for operative mortality and long term survival were identified in 144 patients undergoing mitral valve replacement (MVR). The 3-year survival was 77% at a median follow-up time of 3.01 years, including an early mortality of 7.6%. Nineteen preoperative and perioperative variables were analysed by univariate and multivariate methods. The sole risk factor independently predictive of postoperative death was a poor functional class with a relative risk (RR) of 3.17 compared to patients with a better functional class. Independent risk factors of long term survival were; prior heart operation, presence of mitral regurgitation, age at operation and poor functional class. Estimation of the parameters of the Cox's model gave a predicted 3-year survival ranging from 95% to 11% for the most favourable and the less favourable risk factor combinations. Risk factors that affected late death were the presence of ischemic coronary etiology and poor functional class. Two modes of late death were identified each with its prognostic factor. The most common mode was cardiac-related death, its sole risk factor was the presence of ischemic coronary etiology. The RR ratio was 3.2 for patients with ischemic coronary etiology, compared to patients with other etiologies. Sudden cardiac death was the next, its independent risk factor was the age at operation with increasing hazard for younger patients. The RR ratio was 8.55 for a 35-year-old patient compared to a 60-year-old patient.

Age Factors↗
PubMed1988

Risk factors in surgically treated aortic and mitral valve disease.

Risk factors in simultaneous aortic and mitral valve replacement were studied in 78 patients. Risk factors for early mortality, according to a stepwise logistic regression model, were male sex, concomitant heart surgery and prior valve replacement. For low-output syndrome, the major morbid event, the risk factors were endocarditic etiology, concomitant heart surgery and prior valve replacement. Survival curves were used to estimate univariate risk factors for total mortality. With a multivariate procedure, using the Cox regression model, two covariates were pin-pointed as independent prognostic factors in total mortality, viz. mitral regurgitation and concomitant heart surgery. The Cox model also showed the two covariates ischemic heart disease and endocarditic etiology to be risk factors in late mortality. Predicted 3-year survival was estimated with different combinations of these risk factors. The results were compared with earlier reports.

Aged↗
PubMed1988

Surgical repair of aortico-left ventricular tunnel (ALVT).

ALVT is a very rare congenital malformation. Until 1983 a collective review reported only 37 cases published. A 5-month-old girl with a body weight of 5.5 kg was referred for cardiomegaly and cardiac murmur. 2D-echo revealed the diagnosis which was later confirmed by angiography. The child was then operated upon with extracorporeal circulation using deep hypothermia (20 degrees C). The aortic orifice of the tunnel was closed with 3 pledget reinforced sutures. Cross-clamp time was 17 min. Electromagnetic flowmetry suggested an insufficiency of 78% preoperatively, and postoperatively this was reduced to 6%. Angiography was performed two weeks postoperatively, revealing mild valvular aortic insufficiency. She was discharged from the hospital 15 days postoperatively. ALVT should be corrected surgically as soon as the diagnosis is made.

Aorta↗