Search PubMed⌕ Search

Biomedical subjects

B S Rasmussen

Publications and source records attributed to B S Rasmussen.

18 recordsLinked to original sources
PubMed2006

Oxygenation within the first 120 h following coronary artery bypass grafting. Influence of systemic hypothermia (32 degrees C) or normothermia (36 degrees C) during the cardiopulmonary bypass: a randomized clinical trial.

BACKGROUND: Lung function is often impaired after cardiac surgery performed under cardiopulmonary bypass (CPB). Normothermic CPB has become more common, but it remains unknown whether it reduces post-operative lung function compared with hypothermic CPB. The aim of this study was to investigate oxygenation within the first 120 h after systemic hypothermia and normothermia under CPB. METHODS: Thirty patients undergoing coronary artery bypass grafting (CABG) were randomized to either hypothermic (32 degrees C) or normothermic (36 degrees C) CPB. Oxygenation was studied by a simple method for the estimation of intrapulmonary shunt and ventilation-perfusion (V/Q) mismatch pre-operatively and 4, 48 and 120 h post-operatively by changing Fio2 in four to six steps. V/Q mismatch was described with DeltaPo2 (normal values, 0-2.38 kPa). RESULTS: Shunt and V/Q mismatch (DeltaPo2) increased post-operatively in both groups (P<0.01), with no differences between the groups, and with the nadir values 48 h after surgery, i.e. shunt of 15% (5.8-25%) and DeltaPo2 of 3.0 kPa (0.8-14 kPa) [values given as median (range)]. CONCLUSIONS: Impaired oxygenation is prevalent and prolonged following CABG, with equal intensity after hypothermic and normothermic CPB.

Adult↗
PubMed1998

[Mortality and worsening of prognosis for patients with aortic stenosis while on the waiting list].

In a prospective study, 99 consecutive patients with an operative indication due to severe aortic stenosis (AS) were put on a surgical waiting list. The waiting time to aortic valve replacement (AVR) averaged 6.3 months (0.5-19 months). There were 58 men and 41 women with a mean age of 61 years (21-82 years). The patients were divided into three groups: group 1 (N = 81) with an uneventful stay on the waiting list; group 2 (N = 11) with significant worsening of a prognostic index; and group 3 (N = 7) with patients who died during the waiting time. The waiting list death rate was 13.5%/patient-year compared with a post-AVR death rate of 4.9% patient-year (p < 0.05) with a mean post-AVR follow-up of 5.7 years. According to a prognostic index (Cox regression model) at inclusion, group 2 patients had a predicted 7-year post-AVR survival probability of 72%, but only of 61% according to their prognostic index immediately preoperatively; their observed 7-year post-AVR survival was 60%. Logistic regression analysis identified high age, short duration of symptoms, signs of severe hypertrophy and strain in the ECG, female gender, and deranged left ventricular diastolic function (related to severely increased left ventricular muscle mass) as independent predictors of prognostic worsening and death while on the waiting list. The predictive models did not allow sufficiently accurate identification of the patients at risk during the waiting period. The consequences of a surgical waiting period averaging 6 months are serious for AS patients. The death rate is high and a subgroup worsens its prognostic profile with a significantly reduced post-AVR long-term survival as the result.

Adult↗
PubMed1998

Myocardial structure as a determinant of pre- and postoperative ventricular function and long-term prognosis after valve replacement for aortic stenosis.

BACKGROUND: Long-term results after aortic value replacement for aortic stenosis can be correlated to a cardiac-related pre-operative risk profile. This predictability indicates that there is a common basis in subtle or overt structural abnormalities of left ventricular myocardium. METHODS AND RESULTS: Forty-nine patients aged 24-82 (mean 61) years, with aortic stenosis had a full wall thickness transmural biopsy of the left ventricular antero-lateral free wall during aortic valve replacement. Echocardiography and radionuclide ventriculography were performed prior to, and 18 months (n = 41) after, the operation. Postoperative follow-up to a maximum of 7.7 years was 100% complete. Pre-operatively, all patients had an increase in both the left ventricular mass index (202 +/- 67 g.m-2) and the muscle cell diameter (41 +/- 8 microns); other morphological data included a muscle cell nucleus volume of 752 +/- 192 microns3, a muscle cell mass index of 163 +/- 54.m-2, and a fibrous tissue mass index of 39 +/- 16 g.m-2. Patients with a pre-operative episode of clinical left ventricular failure (n = 19) had significantly greater morphological variables than those without. Pre-operative ejection fraction and other measures of systolic function correlated inversely with the morphological data, except for the fibrous tissue mass index; diastolic function indices correlated inversely with all the morphological variables. At the 18-month re-study, the same general picture was noted, but with an underlying strengthening, especially of the muscle cell mass index. Overall, the mass index dropped to 152 +/- 51 g.m-2 (P < 0.0001), but in 17% of the patients it became normal; the mass index at 18 months was directly correlated to morphological variables. A high muscle cell nucleus volume was identified as an independent predictor of early and late mortality. CONCLUSIONS: Abnormalities of the hypertrophied left ventricular muscle cell and the degree of muscle hypertrophy are, to some degree, underlying determinants of pre-operative symptomatology, pre- and postoperative ventricular function, and early and late mortality after valve replacement for aortic stenosis. Incomplete hypertrophy impaired results, was related to pre-operative myocardial structural abnormalities.

Adult↗
PubMed1997

Impact of size mismatch and left ventricular function on performance of the St. Jude disc valve after aortic valve replacement.

BACKGROUND: The hemodynamic function of the St. Jude valve may change relative to changes in left ventricular function after aortic valve replacement for aortic stenosis. From theoretical reasons one may hypothesize that prosthetic valve hemodynamic function is related to left ventricular failure and mismatch between valve size and patient/ventricular chamber size. METHODS: Forty patients aged 24 to 82 years who survived aortic valve replacement for aortic stenosis with a standard St. Jude disc valve (mean size, 23.5 mm; range, 19 to 29 mm) were followed up prospectively with Doppler echocardiography and radionuclide left ventriculography preoperatively and 9 days, 3 months, and 18 months after the operation with assessment of intravascular hemolysis at 18 months. Follow-up to a maximum of 7.4 years (mean, 6.3 years) was 100% complete. RESULTS: Left ventricular muscle mass index decreased from 198 +/- 62 g.m-2 preoperatively to 153 +/- 53 g.m-2 at 18 months (p < 0.001), paralleled by a significant increase in left ventricular ejection fraction, peak ejection rate, and peak filling rate; only 18% of the patients had normal left ventricular muscle mass index and only 32% normal ventricular function (normal left ventricular ejection fraction, peak ejection rate, peak filling rate, early filling fraction, and late filling fraction during atrial contraction) at 18 months. Prosthetic valve peak Doppler gradient dropped from 20 +/- 6 mm Hg at 9 days to 17 +/- 5 mm Hg at 18 months (p < 0.05). Reduction of left ventricular muscle mass index was unrelated to peak gradient and size of the valve. Peak gradient at 18 months rose with valve orifice diameter of 17 mm or less (by 6 mm Hg), orifice diameter/body surface area of 9 mm.m-2 or less (by 5 mm Hg), left ventricular enddiastolic dimension (by 23 mm Hg per 10 mm increase), and impaired ventricular function (by 3 mm Hg). All but 2 patients (5%) had intravascular hemolysis; none had anemia. Two patients with moderate paravalvular leak had the highest serum lactic dehydrogenase levels; 4 patients with trivial leak had higher serum lactic dehydrogenase levels than those without leak. Serum lactic dehydrogenase levels rose with moderate paravalvular leak, impaired ventricular function, and valve orifice diameter. Six patients with trivial or moderate paravalvular leak had a cumulative 7-year freedom from bleeding and thromboembolism of 44% +/- 22% compared with 87% +/- 5% for those without leak (p < 0.05). CONCLUSIONS: The peak gradient of the St. Jude aortic valve dropped marginally over the first 18 postoperative months in association with incomplete left ventricular hypertrophy regression and marginal improvement of ventricular function. Mismatch between valve size and ventricular cavity size or patient size and impaired function of a dilated ventricle significantly compromised the performance of the St. Jude valve. Probably explained by platelet destruction or activation, paravalvular leak was related to bleeding and thromboembolic complications.

Adult↗
PubMed1997

Left ventricular systolic and diastolic function in aortic stenosis. Prognostic value after valve replacement and underlying mechanisms.

AIMS: The aims of the study were to examine the prognostic value of pre-operative left ventricular systolic and diastolic function on early, and late mortality after valve replacement for aortic stenosis, and to identify possible underlying mechanisms. METHODS AND RESULTS: Ninety-one prospectively recruited consecutive patients with a mean age of 61 years underwent valve replacement for aortic stenosis with concomitant coronary artery bypass grafting in 32 and a minimum postoperative observation period of 5.4 years. There were six early (< or = 30 days postoperatively) and 19 late deaths, and 18 deaths from specific causes (cardiac and prosthetic valve related). Early mortality occurred exclusively among patients with a combined subnormal left ventricular systolic function (subnormal ejection fraction or peak ejection rate, or supranormal time-to-peak ejection--duration of systole ratio) and a subnormal fast filling fraction. In Cox regression models on crude mortality and specific deaths, a subnormal ejection fraction and a fast filling fraction of < or = 45% were the only independent risk factors. Patients with none of these risk factors had normal sex- and age-specific survival, those with any one factor had an early, and those with both factors a massive early and a late excess mortality, with 5-year crude survival of 92%, 77%, and 50%, respectively (P < 0.0001). Systolic wall stress was without prognostic value. Further analyses indicated that impairment of left ventricular function occurred with increasing muscle mass over two phases: (1) diastolic dysfunction characterized by a pattern of severe relative concentric hypertrophy; (2) the addition of systolic dysfunction characterized by a more dilated, less concentric chamber geometry. Coronary artery disease seemed to provoke the latter development sooner. CONCLUSIONS: Impaired systolic and diastolic left ventricular function, irrespective of afterload, were decisive independent pre-operative risk factors for early as well as late mortality after aortic valve replacement for aortic stenosis. The adverse influence of concentric hypertrophy was the main underlying mechanism. Operative intervention, before impairment of diastolic and systolic function, should be advocated.

Adult↗
PubMed1994

[Data and quality assurance tools from a new cardiac center in Denmark].

Open heart surgery was established at Aalborg Hospital in 1992. In the time period March to December 1992 cardiac anaesthesia was administered in 98 operations utilizing extracorporeal circulation and cardiopulmonary bypass. Mortality in coronary artery surgery was 1.6%. All patients were prospectively registered using a new dataform allowing registration of 228 patients related variables concerning preoperative status, course of anaesthesia and perfusion, surgery and postoperative intensive care. Quality assurance in cardiac surgery requires risk factor analysis, and registration of numerous data is a necessary tool. The software for our database system has been developed and programmed using the database programme dBASE IV from the Ashton/Tate Corporation.

Adult↗
PubMed1993

[Surgical treatment of hydronephrosis. Late results after surgery using the Anderson-Hynes method].

Twenty-one patients with hydronephrosis mean age 37 years (11-72) were operated using Anderson-Hynes pyeloplasty, without routine use of a nephrostomy catheter. One patient developed urinary leakage postoperatively, which ceased after insertion of a ureteric catheter. Follow-up assessment was performed after a mean observation time of 85 months (44-142). Clinical examination, laboratory investigations, urography and renography were performed preoperatively and at follow-up. No signs of stones or stenosis in the pelvis were found. The patients operated upon before the age of 30 showed improved postoperative renal function. All patients had symptoms preoperatively, but only one had symptoms postoperatively. It can be concluded that the results of surgical intervention in hydronephrosis are excellent, especially in patients below 30 years.

Adolescent↗
PubMed1992

Long-term follow-up of patients with hydronephrosis treated by Anderson-Hynes pyeloplasty.

A series of 21 patients with hydronephrosis (mean age 37 years) underwent an Anderson-Hynes pyeloplasty; a nephrostomy catheter was not used routinely. One patient developed urinary leakage post-operatively but this ceased following insertion of a ureteric catheter. Assessment was carried out after a mean observation time of 85 months. Clinical examination, laboratory investigations, urography and renography were performed pre-operatively and at follow-up. There was no evidence of stones or stenosis in the pelvis. Patients operated upon before the age of 30 years showed improved renal function. All patients had symptoms pre-operatively but only one had symptoms post-operatively. It was concluded that the results of surgical intervention in hydronephrosis are excellent, especially in patients aged less than 30 years.

Adolescent↗
PubMed1989

Postspinal headache in young and elderly patients. Two randomised, double-blind studies that compare 20- and 25-gauge needles.

In two randomised, double-blind studies of elderly patients with a mean age of 68.9 (range 21-88) years and young patients, mean age 29.4 (range 20-40) years, the effect of needle size on the incidence of postspinal headache was compared. The two needle groups, 20- and 25-gauge, were comparable in both studies with regard to number, sex, age and type of surgery. The incidence of postspinal headache in young patients was 27.6% when a 20-gauge needle was used and 12.6% with a 25-gauge needle. There was no significant difference in either the incidence of headache in the elderly patients (10.8% and 7.8%, respectively) or between the sexes. It is concluded that it does not matter if a 20- or a 25-gauge needle is used for spinal analgesia in elderly patients with regard to postspinal headache, but if spinal analgesia is indicated in young patients a fine needle is preferred.

Adult↗
PubMed1988

Impaired pulmonary and cardiac function after maximal exercise.

The cardiopulmonary response to maximal rowing exercise of short duration was studied in six healthy well-trained oarsmen. The lung diffusing capacity for carbon monoxide was significantly decreased below the pre-exercise value for 2.5 days post-exercise (P less than 0.05). Residual volume (RV) showed a significantly increased value at 30 min of recovery (P less than 0.01) with no change in total lung capacity. There was no significant change in transthoracic electrical impedance following exercise but a decrease may have been masked by the increased RV. The changes in the pulmonary parameters may reflect the occurrence of a transient interstitial lung oedema. Exercise-induced bronchoconstriction may be a part of the cardiopulmonary response as peak expiratory flow rate (PEFR) was significantly reduced at 30 min of recovery. The reason for the increase in pulmonary extravascular water volume may be a marked distension of the lung capillaries due to increased blood volume in the lungs and as a consequence increased vascular permeability. The changes may also be caused by impaired myocardial contractility indicated by a split impedance dZ/dt waveform, not previously described in healthy persons, which occurred in all six subjects immediately following exercise.

Adolescent↗
PubMed1986

Decrease in pulmonary diffusion capacity after maximal exercise.

Oppression of the chest, cough and orthopnea are well known to occur in some athletes after competitions, maybe reflecting an increase in lung water. In order to indicate if lung water increases after maximal exercise we measured pulmonary diffusion capacity before and 2.1 h after a short maximal arm exercise bout in 11 canoeists and showed a decrease of 6.7%. The result may be explained by a calculated 17% increase in alveolar interstitial volume.

Adolescent↗
PubMedDate not supplied

Intrapleural administration of 0.5% plain bupivacaine compared to 0.5% epinephrine: a hemodynamic and ventilatory study.

The ventilatory and hemodynamic effects of 20 ml 0.5% intrapleural bupivacaine with and without 5 micrograms/ml epinephrine were studied. Ten patients scheduled for intrapleural block in the treatment of chronic visceral pain had a left-sided intrapleural catheter inserted. In a double-blind, crossover design they received 20 ml 0.5% bupivacaine with and without 5 micrograms/ml epinephrine. Forced vital capacity, vital capacity, and forced expiratory volume in one second were measured before and 30 minutes after the injection. Mean blood pressure, heart rate, and cardiac output were recorded before the injection and at five-minute intervals for 30 minutes. Vital capacity, forced vital capacity, and forced expiratory volume in one second were unchanged in both groups. There were no differences in any of the pulmonary function tests between the groups. When data from both groups are pooled, vital capacity shows a decrease of 7% (p less than 0.05). No changes in heart rate or mean blood pressure were seen in either group. Bupivacaine without epinephrine did not affect the cardiac output, whereas bupivacaine with epinephrine resulted in a rise in cardiac output of 15% at 15 and 20 minutes after the injection. We did not find any major effects of intrapleural injection of 20 ml 0.5% bupivacaine with and without 5 micrograms/ml epinephrine on ventilatory capacity or cardiovascular function in patients treated for chronic visceral pain.

Adult↗