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Biomedical subjects

L Ekström

Publications and source records attributed to L Ekström.

At least 55 records · Page 3Linked to original sources
PubMed1995

Prognosis among survivors of prehospital cardiac arrest.

STUDY OBJECTIVE: To describe the prognosis in consecutive patients discharged from hospital after prehospital cardiac arrest. PATIENTS: All patients in the community of Göteborg who were discharged from hospital after out-of-hospital cardiac arrest between 1981 and 1991. RESULTS: Two hundred forty-three patients were discharged from hospital during the observation period, of whom 80% initially experienced ventricular fibrillation. Among patients discharged, 21% died during the first year; after 10 years, 82% had died. Age, sex, previous history of cardiovascular disease, circumstances at the time of cardiac arrest, complications during hospitalization, and discharge medications were assessed as predictors of 1-year mortality. Independent predictors of death during follow-up were history of myocardial infarction (P < .001), no prescription of beta-blockers at discharge (P < .01), age (P < .05), and cerebral performance category (CPC) at discharge (P < .05). CONCLUSION: Among patients who survived out-of-hospital cardiac arrest, one of five died during the first year and one of five survived 10 years after discharge. Prognosis was associated with a history of myocardial infarction, prescription of beta-blockers at discharge, age, and CPC at discharge.

Adolescent↗
PubMed1995

In vivo measurement of spinal column viscoelasticity--an animal model.

The goal of this study was to measure the in vivo viscoelastic response of spinal motion segments loaded in compression using a porcine model. Nine pigs were used in the study. The animals were anaesthetized and, using surgical techniques, four intrapedicular screws were inserted into the vertebrae of the L2-L3 motion segment. A miniaturized servohydraulic exciter capable of compressing the motion segment was mounted on to the screws. In six animals, a loading scheme consisting of 50 N and 100 N of compression, each applied for 10 min, was used. Each loading period was followed by 10 min restitution with zero load. The loading scheme was repeated four times. Three animals were examined for stiffening effects by consecutively repeating eight times 50 N loading for 5 min followed by 5 min restitution with zero load. This loading scheme was repeated using a 100 N load level. The creep-recovery behavior of the motion segment was recorded continuously. Using non-linear regression techniques, the experimental data were used for evaluating the parameters of a three-parameter standard linear solid model. Correlation coefficients of the order of 0.85 or higher were obtained for the three independent parameters of the model. A survey of the data shows that the viscous deformation rate was a function of the load level. Also, repeated loading at 100 N seemed to induce long-lasting changes in the viscoelastic properties of the porcine lumbar motion segment.

Animals↗
PubMed1994

Effect of strain rate and bone mineral on the structural properties of the human anterior longitudinal ligament.

The effect of strain rate and bone mineral content on the biomechanical properties of the human lumbar anterior longitudinal ligament-bone complex was studied. Tensile structural properties were determined for 54 such preparations subjected to distraction rates ranging from 0.1-230 mm/sec. The ultimate load as well as the stiffness of the bone-ligament complex increased more than 50% over this strain rate range. A high correlation between bone mineral and structural properties of the ligament-bone complex was also noted. These findings suggest that, in development and construction of spine models for prediction of injury risks, one should consider the effect of different loading rates as well as the inherent properties (i.e., bone mineral content) of the biological material.

Adult↗
PubMed1994

Survival after cardiac arrest outside hospital over a 12-year period in Gothenburg.

BACKGROUND: A two-tiered ambulance system with a mobile coronary care unit and standard ambulance has operated in Gothenburg (population 434,000) since 1980. Mass education in cardiopulmonary resuscitation (CPR) commenced in 1985 and in 1988 semiautomatic defibrillators were introduced. AIM: To describe early and late survival after cardiac arrest outside hospital over a 12-year period. TARGET POPULATION: All patients with prehospital cardiac arrest in Gothenburg reached by mobile coronary care unit or standard ambulance between 1980 and 1992. RESULTS: The number of patients with cardiac arrest remained fairly steady over time. Among patients with witnessed ventricular fibrillation, the time to defibrillation decreased over time. The proportion of patients in whom bystander initiated CPR was increased only moderately over time. The proportion of patients given medication such as lignocaine and adrenaline successively increased. The number of patients with cardiac arrest who were discharged from hospital per year remained steady between 1981 and 1990 (20 per year), but increased during 1991 and 1992 to 41 and 31 respectively. CONCLUSIONS: Improvements in the emergency medical service in Gothenburg over a 12-year period have lead to: (1) a shortened delay time between cardiac arrest and first defibrillation and (2) an improved survival of patients with cardiac arrest outside hospital probably explained by this shortened delay time.

Adult↗
PubMed1994

Predictors of early and late survival after out-of-hospital cardiac arrest in which asystole was the first recorded arrhythmia on scene.

BACKGROUND: A large proportion of patients who suffer out-of-hospital cardiac arrest have asystole as the initial recorded arrhythmia. Since they have a poor prognosis, less attention has been paid to this group of patients. AIM: To describe a consecutive population of patients with out-of-hospital cardiac arrest with asystole as the first recorded arrhythmia and to try to define indicators for an increased chance of survival in this population. SETTING: The community of Gothenburg. PATIENTS: All patients who suffered out-of-hospital cardiac arrest during 1981 to 1992 and were reached by our emergency medical service (EMS) system and where cardiopulmonary resuscitation (CPR) was attempted. RESULTS: In all there were 3434 cardiac arrests of which 1222 (35%) showed asystole as the first recorded arrhythmia. They differed from patients with ventricular fibrillation by being younger, including more women and having a longer interval between collapse and arrival of the first ambulance. In all 90 patients (7%) were hospitalized alive and 20 (2%) could be discharged from hospital. Independent predictors for an increased chance of survival were: (a) a short interval between the collapse and arrival of the first ambulance (P < 0.001) and the time the collapse occurred (P < 0.05). Initial treatment given in some cases with adrenaline, atropine and tribonate were not associated with an increased survival. CONCLUSIONS: Of all the patients with out-of-hospital cardiac arrest, 35% were found in asystole. Of these, 7% were hospitalized alive and 2% could be discharged from hospital. Efforts should be made to improve still further the interval between collapse and arrival of the first ambulance.

Adolescent↗
PubMed1994

Survival in patients found to have ventricular fibrillation after cardiac arrest witnessed outside hospital.

Since 1980 an Emergency Medical Service (EMS) system with a two-tier ambulance service has been operating in Göteborg. During this 12-year period, all cardiac arrests outside hospital have been monitored. Cardiopulmonary resuscitation (CPR) training for the general public began in 1985 and, by the end of 1992, 125 000 persons had been trained. The aim of this study was to define the factors associated with an increased chance of survival after cardiac arrest witnessed out-of-hospital and secondary to ventricular fibrillation. The study group comprises all patients with cardiac arrest witnessed outside hospital in Göteborg between 1980 and 1992, in whom CPR was initiated by our EMS and ventricular fibrillation observed at the first ECG recording. In a multivariate analysis of age, sex, time of collapse, interval between collapse and first defibrillation, bystander-initiated CPR, the following factors were associated with an increased chance of being discharged from hospital: (1) Short interval between collapse and first defibrillation (P < 0.001); (2) Bystander-initiated CPR (P < 0.001); and (3) Age (P < 0.05). Among patients with an out-of-hospital cardiac arrest who were found by the EMS personnel to have ventricular fibrillation, the predictors of survival were: interval between collapse and defibrillation, bystander-initiated CPR and age.

Adolescent↗
PubMed1994

Risk indicators for, and symptoms associated with, death among patients hospitalized after out-of-hospital cardiac arrest.

BACKGROUND: An increasing proportion of patients who have an out-of-hospital cardiac arrest are initially successfully resuscitated and thus hospitalized. AIMS: To define risk indicators for, and to describe the mode of, in-hospital death among patients hospitalized after an out-of-hospital cardiac arrest. SETTING: Göteborg, Sweden. PATIENTS: All patients hospitalized after out-of-hospital cardiac arrest between 1980 and 1992. RESULTS: A total of 707 out of 3434 patients were hospitalized after out-of-hospital cardiac arrest, of whom 278 (39%) were discharged alive. Independent risk indicators for in-hospital death were: type of initial arrhythmia on the scene, age, interval between cardiac arrest and arrival of first ambulance, bystander-initiated cardiopulmonary resuscitation and history of diabetes mellitus. Of the patients who died in hospital, 88% had brain damage and 43% myocardial damage. CONCLUSION: Risk indicators for hospital death can be defined. The majority of in-hospital deaths were associated with brain damage.

Aged↗
PubMed1994

Effect of bystander initiated cardiopulmonary resuscitation on ventricular fibrillation and survival after witnessed cardiac arrest outside hospital.

OBJECTIVE: To describe the proportion of patients who were discharged from hospital after witnessed cardiac arrest outside hospital in relation to whether a bystander initiated cardiopulmonary resuscitation. PATIENTS: All patients with witnessed cardiac arrest outside hospital before arrival of the ambulance and in whom cardiopulmonary resuscitation was attempted by the emergency medical service in Gothenburg during 1980-92. RESULTS: Cardiopulmonary resuscitation was initiated by a bystander in 18% (303) of 1,660 cases. In this group 69% had ventricular fibrillation at first recording compared with 51% in the remaining patients (P < 0.001). Among patients in whom cardiopulmonary resuscitation had been initiated by a bystander 25% were discharged alive versus 8% of the remaining patients (P < 0.001). Independent predictors of survival were in order of significance: initial arrhythmia (P < 0.001), interval between collapse and arrival of first ambulance (P < 0.001), cardiopulmonary resuscitation initiated by a bystander (P < 0.001), and age (P < 0.01). Among patients who were admitted to hospital alive 30% of patients in whom cardiopulmonary resuscitation had been initiated by a bystander compared with 58% of remaining patients (P < 0.001) had brain damage and died in hospital. Corresponding figures for death in association with myocardial damage were 18% and 29% respectively (P < 0.01). CONCLUSIONS: Cardiopulmonary resuscitation initiated by a bystander maintains ventricular fibrillation and triples the chance of surviving a cardiac arrest outside hospital. Furthermore, it seems to protect against death in association with brain damage as well as with myocardial damage.

Age Factors↗
PubMed1994

Bone mineral content and fixation strength of femoral neck fractures. A cadaver study.

We measured the bone mineral content (BMC) of 21 human femoral autopsy specimens using Radiographic Attenuation Technique (RAT). The specimens were then tested for stiffness in a material-testing machine. Osteosynthesis was performed after medial femoral neck osteotomy, using 1 of 3 different pinning methods: 2 hook pins (LIH), 2 cannulated screws (Uppsala), and 3 cannulated screws (CHP). The specimens were allocated to each method by grouping them in triplets with similar BMC. Cyclic loading at 500-1000 N and 1 Hz was performed during 50 minutes. The amount of axial compression during loading was measured. Finally, loading to failure was done and post-fixation stiffness and ultimate compression strength recorded. With one exception, all cases failed where the BMC was less than 0.4 g/cm2. No differences between the methods of osteosynthesis were found. The fixation strength was mostly dependent on the strength of the bone, i.e., the degree of osteoporosis.

Aged↗
PubMed1993

Structural properties of the anterior longitudinal ligament. Correlation with lumbar bone mineral content.

The relationship between the amount of bone in the lumbar spine and ligamentous properties has not been studied. This article reports the tensile structural properties of bone-ligament-bone preparations of the anterior longitudinal ligament from 15 human lumbar spine segments. Significant correlations were found between the vertebral bone mineral content expressed as BMC (g/cm) and BMA (g/cm2) and BMD (g/cm3) and the structural properties of the vertebral bone-anterior longitudinal ligament-bone complex determined at yield and failure. These findings suggest that the amount of bone tissue in the spine may be functionally related to structural properties of the spinal ligaments.

Adult↗
PubMed1993

[Double emergency medical service system in Göteborg].

During 1989-1991, the mobile coronary care unit (MCCU) in Gothenburg answered 10,908 calls. The most frequent cause of alarm calls was chest pain (21 per cent), whereas cardiac arrest accounted for 9 and surgical cases for 15 per cent. Severe pain was most frequent among patients with chest or abdominal pain. Despite the high frequency of chest pain, only a third of the myocardial infarction cases were attended by the MCCU. Of all cases of out-of-hospital cardiac arrest where resuscitation was attempted, 26 per cent were alive at admission to hospital, and 10 per cent at discharge, as compared with 48 and 22 per cent, respectively, among the subgroup with bystander-witnessed cardiac arrest and ventricular fibrillation as an initial finding.

Coronary Care Units↗
PubMed1992

Mechanical properties of the human lumbar anterior longitudinal ligament.

A new technique incorporating a motion analysis system and a materials testing machine was used to investigate regional differences in the tensile mechanical properties of the lumbar spine anterior longitudinal ligament (ALL). Bone-ALL-bone specimens were prepared from young human cadaveric motion segments with no disc or bony pathology. Each specimen was distracted until failure at a constant crosshead displacement rate of 2.5 mm s-1 (approximately 1.0% strain per second). Strains were evaluated from digitized video recordings of markers attached to the ALL at 12 sites along its length and width, including the ligament substance and insertions. The 'overall' strain in the ligament was calculated from the outermost pairs of markers along the ligament length. The average tensile strength, the 'overall' tensile modulus and the 'overall' strain of the ALL at failure were 27.4 MPa (S.D. 5.9), 759 MPa (S.D. 336) and 4.95% (S.D. 1.51), respectively. Large and significant variations in the strains were present along the width and length of the ALL. Peak substance strains were over twofold greater than peak strains at the ligament insertion sites, whereas across the ligament width, peak strains in the outer portion of the ligament were over 40% greater than in the central region. Failure consistently occurred in the ligament mid-substance and ultimate strains at the ligament failure site averaged 12.1% (S.D. 2.3). These results indicate that the strains are highly nonuniform in the normal ALL.

Adult↗
PubMed1991

Higher recurrence rate after coronary angioplasty in unstable angina pectoris.

PURPOSE: Recurrent stenosis after percutaneous transluminal coronary angioplasty (PTCA) is a significant problem, requiring repeat dilation in about one-third of all treated patients. Various clinical and procedure-related predictors have been proposed. Between 1983 and 1987, 257 patients underwent 322 procedures, where 380 stenoses were attempted. Indications were: stable angina pectoris 73%, unstable angina pectoris 22%, other indication 5%. The primary success rate was defined as a less than 50% remaining postprocedure stenosis. FINDINGS: Repeat angiograms were done for 88% of the initially successful cases, either six months after PTCA or if there was a clinical recurrence. Restenosis was defined as a recurrence of a more than 50% diameter stenosis. The restenosis rate was 33% and was significantly higher (p less than 0.05) for unstable (46%) than for stable angina pectoris (29%). There was a nonsignificant tendency to a higher restenosis rate in the left anterior descending artery than in the other coronary vessels. IMPLICATIONS: The increased restenosis rate seen after PTCA for unstable angina pectoris could be caused by a higher activity in systems affecting the proliferative processes in the smooth muscle cells of the arterial wall, which is thought to form the pathophysiologic basis for restenosis after PTCA.

Adult↗
PubMed1991

Prehospital thrombolysis in suspected acute myocardial infarction: results from the TEAHAT Study.

In a randomized, double-blind study, rt-PA vs. placebo treatment in early suspected acute myocardial infarction (AMI) was evaluated in patients both in hospital and prehospitally. The inclusion criteria were as follows: (a) age less than 75 years; and (b) chest pain indicative of AMI, of no longer than 2.75 h duration before first examination. In the prehospital setting a mobile coronary-care unit, accompanied by a cardiologist, was sent out by the ambulance services to 350 patients, of whom 205 (59%) were classified as non-eligible when examined by the cardiologist. Of the 145 patients who fulfilled the inclusion criteria, 44 were excluded due to contraindications to thrombolytic treatment. Thus 101 patients were randomized to blinded treatment outside hospital. The median time interval between onset of pain and treatment was 75 min, 45 min less than for those subjects who were randomized in hospital. The prevalence of confirmed AMI was 42% in the prehospital group, compared to 66% in the hospital group. Bleeding and cardiac complications for prehospital treatment were few, and similar to those for hospital treatment. In conclusion, prehospital thrombolysis was feasible, and delay times prior to treatment were significantly reduced. However, the specificity and diagnostic accuracy were lower than those achieved with in-hospital therapy.

Aged↗
PubMed1990

Buccal nitroglycerin decreases ischemic pain during coronary angioplasty: a double-blind, randomized, placebo-controlled study.

Nitroglycerin (NTG) has the potential to reduce myocardial ischemia during percutaneous transluminal coronary angioplasty (PTCA). Buccal administration of NTG offers practical advantages compared to intravenous or intracoronary administration. In a double-blind, randomized, placebo-controlled study, 100 patients were given 5 mg of buccal NTG or placebo during PTCA. A scoring system for ischemic pain during balloon inflation was defined as pain intensity (0 to 5) multiplied by duration of pain after balloon deflation (1 = 0 to 30 seconds, 2 = 30 to 60 seconds, 3 = 60 to 120 seconds, 4 = greater than 120 seconds but subsiding, and 5 = until next inflation). Fourteen patients were excluded: 12 for vagal reaction (eight NTG and four placebo; p greater than 0.05) requiring atropine, making buccal absorption unreliable, and two for inability to dilate. Eighteen patients (nine NTG and nine placebo) had no pain during balloon inflation. Sixty-eight patients (32 NTG and 36 placebo) had ischemic pain with a pain score (mean +/- SD) of 4.8 +/- 3.8 for the NTG group versus 7.1 +/- 4.8 for the placebo group (p = 0.03). We conclude that buccal NTG significantly decreases myocardial ischemia during PTCA.

Administration, Buccal↗
PubMed1988

Contralateral routing of signals in unilateral hearing impairment. A better method of fitting.

Unilaterally severely hearing impaired persons, who may experience substantial communication problems in situations of high acoustic demands, would in theory benefit from contralateral routing of signals (CROS). However, reports of failure because of too much disturbing noise and distortion have been common. The reason for a low success rate in CROS, though, is an inappropriate fitting procedure, due to lack of understanding of the basic principle of CROS among both patients and audiologists. The precondition for success in CROS is an accurate description of the individual hearing deficit and a correctly balanced adjustment of the CROS aid through testing under sound field conditions, combined with a comprehensive follow-up.

Adult↗