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Biomedical subjects

L A Brodin

Publications and source records attributed to L A Brodin.

16 recordsLinked to original sources
PubMed1992

Left ventricular filling as assessed by pulsed Doppler echocardiography after coronary artery bypass grafting.

Diastolic filling of the left ventricle, as assessed by transesophageal pulsed Doppler echocardiography during and in the early phase following coronary artery bypass grafting, was investigated in nine patients without valvular disease or left ventricular hypertrophy. The ratio between the maximal heights of the early diastolic flow-velocity peak and the late (atrial) diastolic flow-velocity peak, the E:A ratio, and also the deceleration time of the early peak were calculated as indices of left ventricular filling. The E:A ratio decreased from 1.01 +/- 0.06 after induction of anesthesia to 0.46 +/- 0.06 on arrival in the intensive care unit (ICU). The E:A ratio then increased and reached 0.87 +/- 0.08 after 6 hours in the ICU. This increase in E:A ratio in the ICU was due to an increasing peak velocity of the E wave. The deceleration time decreased after surgery and increased from 111 +/- 25 to 145 +/- 12 milliseconds in the ICU. Pulsed Doppler indices of diastolic filling are known to be altered by changes in hemodynamic parameters, to be load-dependent, and to vary with heart rate. In the ICU, pulmonary capillary wedge pressure remained unchanged, heart rate decreased by approximately 12%, and systemic vascular resistance decreased by approximately 40%. The changes in hemodynamic parameters could have affected the E:A ratio, but it is unlikely that they could explain the marked increase in the E:A ratio that occurred in the ICU. The results, therefore, imply the presence of impaired diastolic filling immediately after cardiopulmonary bypass with gradual, but not complete, recovery during the first 6 hours in the ICU.

Aged↗
PubMed1991

A comparative study of five different techniques to reduce left ventricular dysfunction during endotracheal intubation.

Thirty-five non-selected, consenting patients were studied during induction of anesthesia before coronary artery bypass grafting. Anesthesia was induced with diazepam, thiopentone and fentanyl, followed by pancuronium. Before induction, 200 MBq Tc 99 m - HSA was given i.v. and ejection fraction (EF) of the left ventricle was measured with a collimated single-crystal probe. The patients were allocated to five groups (seven patients in each) treated with: Group A: nitroglycerin i.v. bolus 4 micrograms x kg-1 given 30-60 s before laryngoscopy; Group B: nitroglycerin i.v. in continuous infusion, 1 micrograms x kg-1 x min-1 started before induction; Group C: two-stage topical anesthesia of the vallecula region and larynx with lidocain; Group D: a combination of nitroglycerin and topical anesthesia (as in Group B and C); and Group E: propranolol i.v. 0.01 mg x kg-1 given 5 min before intubation. All groups reacted in the same way during induction of anesthesia up to the point of laryngoscopy. End-diastolic volume and systemic arterial pressure decreased while cardiac index remained unchanged and EF increased. During laryngoscopy and intubation, however, differences between the groups were evident. Nitroglycerin i.v. as a bolus effectively prevented a reduction in EF and an increase in left ventricular volume. In addition to these beneficial hemodynamic effects, there was a moderate increase in heart rate and a reduction of stroke index. Continuous infusion of nitroglycerin and propranolol i.v. had no effect, since EF fell and left ventricular volume increased. Patients receiving topical anesthesia demonstrated a blunted response to endotracheal intubation with a moderate decrease in EF and an unchanged (Group C) or slightly increased (Group D) left ventricular volume.

Adult↗
PubMed1991

Late cardiac tamponade after open-heart surgery.

Late cardiac tamponade occurred in 74 patients 5-287 (median 16) days after open-heart surgery and was treated with pericardiocentesis or surgery. The overall incidence of late cardiac tamponade was 1.3%. After valve operations it was 2.6% and after isolated coronary surgery 0.7% (53/2,028 vs. 18/2,661, p less than 0.002). The diagnosis was assessed by echocardiography in 93% of cases. Pericardiocentesis, attempted in 65 cases (88%), was curative in 80% but failed in 20%. Eight of the latter 13 underwent emergency surgery and five were medically treated. Failure of pericardiocentesis was associated with posterior location of fluid, clots, echo-free space less than 20 mm or myocardial insufficiency. The subxiphoid part of the wound was surgically re-entered in ten cases and the entire sternotomy in seven. Four patients (5%) died within 30 days of the primary intervention. All hospital survivors were observed for a median of 44 (range 11-115) months. Three (4%) had recurrent pericardial effusion requiring repeat pericardiocentesis, but none had pericardial constriction. The 5-year survival rate was 73%.

Adolescent↗
PubMed1990

Effect of acquisition and analysis routines on gated blood pool measurements.

Results obtained from gated equilibrium blood pool (GBP) studies are not only dependent on intrinsic variations, but also on the way in which images are acquired and analysed. The aim of this study was to investigate factors which could affect left ventricular time-activity curves. Temporal resolution was studied by comparing studies of 20 and 40 frames beat-1. Forty frames per beat resulted in a mean left ventricular ejection fraction of 0.48 compared to 0.46 for 20 frames beat-1. The mean difference of 0.02 was significant (P less than 0.01) as was the mean difference in maximum emptying rate (MER = 0.28, P less than 0.01) and in maximum filling rate (MFR = 0.38, P less than 0.01). No significant differences in ejection fraction (EF) values were found between acquisitions made in list and frame mode, but the mean differences for MER = 0.03 (P less than 0.05) and MFR = 0.01 (P less than 0.02) were significant. For patient repositioning and intra-observer variations no significant differences were found. In patients with normal EF values (greater than 0.5) no significant differences were found in the inter-observer study. In patients with anterior myocardial infarction (AMI), significant differences were found in EF, MER and MFR (EF = 0.02, P less than 0.001; MER = 0.2, P less than 0.01; MFR = 0.24, P less than 0.01). Significant differences were found in all values when comparing a semi-automatic method of evaluation with two automatic methods. In conclusion the results from this study suggest that acceptable reproducibility can be achieved in GBP studies, provided the method of analysis is not changed between studies.

Coronary Circulation↗
PubMed1989

Isoflurane and intravenous anesthesia used for induction before coronary artery bypass grafting.

Induction of anesthesia with isoflurane in combination with fentanyl, thiopentone, nitrous oxide and pancuronium was studied in nine patients scheduled for coronary artery bypass grafting. Ejection fraction (EF) of the left ventricle was monitored with a single crystal probe linked to a microcomputer, after injection of 200 MBq Tc 99m-HSA. Stroke volume index determined by thermodilution and EF were used to calculate left ventricular end-diastolic volume index (LVEDVI). The degree of ischemia was numerically scored as evaluated from the ECG (modified V5 lead). The study protocol covered seven periods from awake before induction to 5 min after intubation. EF decreased moderately during intubation (P less than 0.05). Systemic vascular resistance index (SVRI) was decreased (P less than 0.05) at all times except during intubation when it was unchanged compared to control. LVEDVI decreased during induction (P less than 0.05), while left ventricular filing pressure remained unchanged. Heart rate did not change. Systolic arterial pressure decreased from 147 mmHg (19.6 kPa) to about 100 mmHg (13.3 kPa) during induction (P less than 0.05). Two patients were given vasoconstrictors because of low arterial pressure. The mean ischemic score did not change. One patient, however, had signs of progressive ischemia. In this patient isoflurane administration was stopped after the last recording and the ECG normalized within 20 min.

Aged↗
PubMed1989

Late results after resection of fixed subaortic stenosis.

Resection of fixed subaortic stenosis was performed on 44 patients with median age 14 (range 2-61) years. Concomitant aortic valve pathology was present in 14 (32%) cases (congenital stenosis in 2, thick fibrotic cusps in 8 and incompetent cusps in 4) and other congenital cardiovascular malformations in eight (18%). There was no perioperative mortality. Of the six late deaths, three were due to non-cardiac causes. During follow-up (median 6, range 2-21 years), six reoperations were performed for residual or recurrent obstruction and/or aortic incompetence. Aortic valve replacement was required at two primary and four second operations. Actuarial 5-year and 10-year survival rates were 89% and 76%, respectively, and rates with freedom from cardiac death endocarditis and reoperation 83% and 64%. At follow-up evaluation two patients had significant aortic regurgitation and all survivors had a systolic ejection murmur. At Doppler echocardiography in 29 patients without reoperation, the median pressure difference in the left ventricular outflow tract was 10 (range 0-55) mmHg--in three cases greater than or equal to 30 mmHg. Careful follow-up is advisable after resection of fixed subaortic stenosis, because of the risk of residual or recurrent obstruction and of significant aortic valve incompetence.

Adolescent↗
PubMed1988

Strut-fracture of a Björk-Shiley tilting disc valve diagnosed by echocardiography--a case report.

A 40-year-old man with Björk-Shiley valves implanted in the aortic and mitral positions nine months previously presented with central chest pain. Shortly after admission he developed clinical features consistent with left ventricular failure. Fracture of the mitral prosthesis was diagnosed by echocardiography. At emergency operation the outlet strut of the mitral valve was found to be fractured and the disc was in the left ventricle. The patient survived valve re-placement and is in good health four years later.

Acute Disease↗
PubMed1988

Effects of adenosine-induced hypotension on myocardial hemodynamics and metabolism in fentanyl anesthetized patients with peripheral vascular disease.

The effects of adenosine on central and myocardial hemodynamics and metabolism were evaluated during fentanyl anesthesia (100 micrograms.kg-1) in six patients with peripheral vascular disease. Adenosine was intravenously infused, at a rate of 90 +/- 20 (SEM) micrograms.kg-1.min-1, to reduce mean arterial blood pressure by approximately 20% (23 +/- 2% SEM, from 82 +/- 3 to 63 +/- 3 SEM mmHg) during a 20-min period. Systemic and pulmonary vascular resistance indices decreased by 36 +/- 3 and 32 +/- 6% (SEM), and cardiac index increased by 18 +/- 5%. Heart rate, ventricular filling pressures, and whole body oxygen consumption were not affected by adenosine. Despite the reduced mean arterial blood pressure, coronary sinus flow increased by 128 +/- 26% (SEM) in parallel with a 96 +/- 11% (SEM) increase in coronary sinus oxygen content. Left and right ventricular stroke work indices, as well as myocardial oxygen consumption, were maintained. ECG (12-lead) demonstrated signs of ischemia in one subject, while myocardial lactate uptake was unchanged in all subjects. In conclusion, adenosine-induced hypotension in patients with peripheral vascular disease increased cardiac index without affecting myocardial work, whole body, and myocardial oxygen consumptions. The marked increase in coronary sinus blood flow, indicating coronary vasodilation, was not related to increased myocardial work. Further information regarding myocardial effect of adenosine in patients with ischemic heart disease is warranted.

Adenosine↗
PubMed1988

Changes in ejection fraction during induction of anesthesia with two different i.v. techniques.

Two intravenous induction techniques were compared with respect to changes in ejection fraction (EF) and central hemodynamics in 30 patients scheduled for coronary artery surgery. Left ventricular EF was measured with a collimated single crystal probe linked to a microcomputer, after injection of 200 MBq Tc 99 m HSA. Stroke volume index (SI) determined by thermodilution and EF were used to calculate left ventricular volume in end-systole and end-diastole. In 20 patients (Group I), anesthesia was induced with diazepam (94 micrograms x kg-1), thiopentone (3 mg x kg-1) and fentanyl (3 micrograms x kg-1). In 10 patients (Group II), fentanyl (30 micrograms x kg-1) was used for induction. In Group I, EF decreased from 0.43 to 0.26 at intubation, while systemic vascular resistance index (SVRI) showed an increase. Left ventricular volume decreased during induction of anesthesia except during intubation. In Group II, EF and left ventricular volume remained unchanged during the study period. SVRI showed no increase at intubation. No change in contractility was indicated from the relation between the end-systolic pressure and volume, in any of the groups.

Anesthesia, Inhalation↗