[Prioritization project at the Heart Center in Linköping. Unanimity between politicians and physicians when it comes to ranking of fictitious cases].
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Biomedical subjects
Publications and source records attributed to H Rutberg.
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OBJECTIVE: A major assumption in cardiovascular medicine is that Q-waves on the electrocardiogram indicate major myocardial tissue damage. The appearance of a new Q-wave has therefore been considered the most reliable criterion for diagnosis of perioperative myocardial infarction (PMI) in cardiac surgery. In a study, originally intended to evaluate troponin-T as a marker of PMI, analysis of our data aroused the need to address the reliability of Q-wave criteria for diagnosis of PMI. METHODS: In 302 consecutive patients undergoing coronary surgery, Q-wave and other electrocardiogram (ECG) criteria were compared with biochemical markers of myocardial injury and the postoperative course. All ECGs were analysed by a cardiologist blinded to the biochemical analyses and the clinical course. RESULTS: The incidence of positive Q-wave criteria was 8.1%. Combined biochemical (CK-MB > or = 70 microg/l) and Q-wave criteria were found in 1.0%. Patients with new Q-waves did not have CK-MB or troponin-T levels significantly different from those without Q-waves. More than 25% of the Q-waves were associated with plasma troponin-T below the reference level (< 0.2 microg/l) on the fourth postoperative day. Q-wave criteria alone did not influence the postoperative course. In contrast, biochemical markers correlated with clinical outcome. CONCLUSIONS: The majority of Q-waves appearing after coronary surgery were not associated with major myocardial tissue damage, and according to troponin-T one-fourth of the Q-waves were not associated with myocardial necrosis. Furthermore, the appearance of Q-waves had little influence on short term clinical outcome. Therefore, the use of Q-wave criteria as the gold standard for diagnosis of PMI may have to be questioned.
BACKGROUND: Patients with severe postoperative complications consume a great deal of the economic resources for intensive care. Our knowledge of the late outcome and quality of life of these patients is scarce. METHODS: One thousand five hundred twenty-two patients undergoing cardiac operations during 1991 and 1992 were studied, and the 100 patients who needed the most expensive treatment were identified. The patients were retrospectively risk scored (Higgins score), and the clinical outcome was studied. The surviving patients were followed up for 2 years after the operation. Their quality of life and remaining symptoms were assessed. RESULTS: No significant age difference between groups was observed. There were significantly more women, emergency cases, high-risk patients, and postoperative complications in the studied group. Mortality rate during the first postoperative year was significantly higher in the studied group. Later the difference in mortality rate between the groups decreased. At the 2-year follow-up all the 72 surviving patients in the study group had returned home with less physical and psychological symptoms related to their heart disease. CONCLUSIONS: The cost of treating severe complications in the intensive care unit is high. However, the results of the present study indicate that even a very complicated postoperative course is not incompatible with a successful outcome in the long run.
OBJECTIVE: Aiming at elucidating the effects on capillary blood flow and tissue oxygenation of hyperoxemia during cardiopulmonary bypass, we studied skeletal muscle surface oxygen tensions in 10 patients undergoing elective cardiac operations. METHODS: In a prospective investigation each patient was exposed to normoxemia (arterial oxygen tension 75 to 115 mm Hg) and hyperoxemia (arterial oxygen tension > 185 mm Hg, inspired oxygen fraction = 1.00) during normal anesthetized conditions before and after cardiopulmonary bypass, as well as during normothermic and hypothermic continuous-flow bypass. In each state hemodynamic variables and arterial and mixed venous blood gas and acid base values were measured. From these data oxygen transport variables were calculated. Tissue oxygenation was studied with the use of a multiple-point polarographic oxygen microelectrode, known to provide measures of oxygen tensions at the capillary level. The oxygen distribution profile of such a sample is also indicative of capillary blood flow distribution changes. RESULTS: In all patients and at each occasion of the investigation markedly low mean surface oxygen tensions in skeletal muscle were registered. When hyperoxemia was instituted, a significant decrease in these surface oxygen tensions together with an increase in distribution heterogeneity was seen during all stages. Contrary to prebypass, postbypass, and hypothermic bypass, where vascular resistance, oxygen delivery, and oxygen consumption remained similar during hyperoxemia and normoxemia, a significant (p < 0.05) increase in vascular resistance together with a decline in oxygen consumption was seen during hyperoxemic normothermic (35 degrees to 36 degrees C) cardiopulmonary bypass. CONCLUSION: These findings show that the microcirculatory response to hyperoxemia, seen under other circumstances, persists during continuous-flow cardiopulmonary bypass, normothermic as well as hypothermic. If these adverse effects on tissue oxygenation by hyperoxemia can be further verified and shown to be valid for other organs than skeletal muscle, we would suggest that hyperoxemia should be avoided, especially during normothermic cardiopulmonary bypass.
BACKGROUND: In this study, we describe postoperative monitoring, pharmacologic therapy, and hemodynamic responses in patients receiving Hemopump support after postcardiotomy heart failure. METHODS: The Hemopump was used in 24 patients with severe left ventricular dysfunction after coronary artery bypass grafting. RESULTS: Fourteen patients (58%) were weaned from the Hemopump. Low to moderate doses of a combination of catecholamines, phosphodiesterase inhibitors, vasodilators, and vasoconstrictors were required to optimize Hemopump function and left ventricular unloading. Mean arterial blood pressure, mixed venous oxygen saturation, and urinary output were the most important therapy guidelines. CONCLUSIONS: Together with our clinical protocol, the Hemopump effectively unloaded the failing ventricle while maintaining vital-organ perfusion. Doses of vasoactive drugs could be kept low. This approach to treatment provides good conditions for recovery of the stunned myocardium.
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The aim of this study was to assess the influence of five amino-amide local anesthetic agents on the production of oxygen metabolites in the human polymorphonuclear leukocyte (PMNL), both intra- and extracellularly. Ropivacaine, a new long-acting amino-amide local anaesthetic agent, bupivacaine, lidocaine, mepivacaine and prilocaine in concentrations 1-5 micrograms.ml-1 up to 500-1000 micrograms.ml-1 were compared to an untreated control. PMNLs were isolated from heparinized blood (healthy adult volunteers). Cells were incubated with the various local anaesthetics (37 degrees C, 30 min), then placed in a Biolumat (luminol-amplified chemiluminescence) and stimulated by formyl-methionyl-leucyl-phenylalanine (FMLP), phorbol myristate acetate (PMA) or ionomycin. Horseradish peroxidase (HRP) was added to discriminate between an intra- or extracellular response. In general, a decrease in chemiluminescence-response was seen with higher concentrations (500-1000 micrograms.ml-1) of the various local anaesthetics. Lidocaine showed a decrease even at lower concentrations. A marked increase in intracellular response for prilocaine 1000 micrograms.ml-1 (3894 mumol.l-1) accompanied by a reduction in extracellular response, using FMLP +/- HRP as a stimuli, was noted. Ropivacaine 1000 micrograms.ml-1 (3216 mumol-l-1) showed a decrease both intra- and extracellularly that was similar to, and even somewhat more pronounced than lidocaine 1000 micrograms.ml-1 (3692 mumol.l-1), when using PMA with or without HRP as the stimuli.
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Six subjects susceptible to malignant hyperthermia (MHS) and seven control subjects exercised for 4 min at 120% of their calculated maximal oxygen uptake on a bicycle ergometer. Mean (SEM) muscle pH, measured with a needle-tipped electrode in the vastus lateralis muscle, decreased from a resting value of 7.16 (0.04) to 6.78 (0.04) after exercise in the control group, and from 7.15 (0.05) to 6.56 (0.05) in the MHS group (P less than 0.01 compared with control group). A further decrease in muscle pH to 6.68 (0.06) by 5 min after exercise occurred in the control group, followed by incomplete recovery to 7.06 (0.04) 30 min after exercise. In the MHS group, however, muscle pH decreased to 6.45 (0.05) 5 min after exercise before recovering slowly to only 6.64 (0.07) after 30 min (P less than 0.01 compared with control group). There was no difference in muscle temperature, venous pH or venous lactate concentrations between the two groups. The results show that there is abnormal recovery of muscle pH after short-duration, high-intensity exercise in MHS subjects.
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1. In eight healthy volunteers we compared leg blood flow, as determined in a calf segment by strain-gauge plethysmography, with the flow measured by a constant-rate infusion of Indocyanine Green dye into the femoral artery. The representativeness of the calf segment was evaluated by complementary measurements with additional strain gauges attached around the proximal and distal crural and the distal thigh segments (n = 6). Furthermore, we investigated the influence of the catheterization procedure and a simulated vascular puncture, as well as repeated venous occlusions, on blood flow and on arterial and femoral venous substrate concentrations and blood gases (n = 8). 2. The leg blood flow measured by dye dilution was 0.31 +/- 0.03 litre/min (mean +/- SEM). The blood flow in the calf segments was 14.8 +/- 1.6 ml min-1 litre-1 and no difference between the legs was observed. Extended to the whole leg the plethysmographic blood flow was 0.17 +/- 0.01 litre/min and thus lower (43 +/- 7%, P less than 0.001) than the flow determined by the indicator-dilution method. Blood flow in the legs was not influenced by catheterization or sham punctures of the vessels or by repeated venous occlusions. 3. The concentrations of glucose, lactate and glycerol, as well as blood gas variables, in arterial and femoral venous blood did not change during the study or decreased so slightly (pH and lactate) that the arteriovenous difference was not influenced. 4. We conclude that the blood flow of the total leg cannot be satisfactorily estimated from strain-gauge plethysmography of a single calf segment.(ABSTRACT TRUNCATED AT 250 WORDS)
The metabolic effects of the local administration of propranolol were determined in seven patients undergoing cholecystectomy. Measurements were carried out in the early postoperative period before and after infusion of 2 mg of intraarterial propranolol into the femoral artery of one leg using the other leg as control. Blood flow and arterio-venous concentration differences for oxygen, glucose, lactate, alanine, glycerol and total FFAs were determined. Uptake and release of FFAs were determined by using a tracer technique. The statistical analyses were based on differences between the test and the control leg in changes following the blockade. Glycerol release was significantly more suppressed in the test leg than in the control leg. No difference between the legs was seen in the uptake of oxygen, FFA and glucose or the release of lactate and alanine. The arterial concentration of propranolol was 6.07 +/- 0.72 ng ml-1 (mean +/- SEM). This study indicates that a local beta-blockade by intra-arterial propranolol infusion after surgery slightly reduces the postoperative lipolysis in leg tissues but does not influence or only marginally influences leg blood flow and oxygen uptake or the exchange of glucose, lactate and alanine after moderate surgical trauma.
Thirty-seven women undergoing elective cholecystectomy were randomised into two groups, receiving either lumbar epidural morphine (group L) or epidural morphine via the thoracic route (group T). The effect on pain relief was assessed by a visual analogue scale and included both resting pain and 'provoked' pain. Respiratory parameters (PEF, FEVI and FVC) were also studied. The patients were investigated preoperatively, and 4, 6, 12 and 24 hours after the start of surgery. No significant difference was observed between the groups concerning pain relief or respiratory performance. We conclude that after cholecystectomy lumbar epidural morphine is as effective as thoracic epidural morphine in relieving postoperative pain.
Ten malignant hyperthermia susceptible (MHS) subjects were investigated, all of them positive in in vitro tests. As a control group 12 healthy subjects were investigated. The investigation was done in a blind fashion during strictly standardized conditions. Electromechanical delay of contraction and half contraction time to tetanus were faster (P less than 0.05) while half relaxation time was shorter in the MHS subjects (P less than 0.05). Skin and intramuscular temperature were significantly higher in the MHS subjects (P less than 0.05). This indicates that MHS subjects differ in various skeletal muscle characteristics during "normal" conditions. Further studies to define the temperature level at which the test of muscle function is most discriminating are needed before it can be used for diagnostic purposes.
A patient who developed an epidural haematoma with multifactorial aetiology (bleeding diathesis, ankylosing spondylitis, chronic alcoholism and acute pancreatitis) after epidural analgesia for pain relief is described. Our conclusion is that adequate laboratory screening of blood coagulation, including platelet count, should be carried out in this category of patient before attempted epidural blockade, the risks of which must be weighed against the benefits. The block should be allowed to wear off intermittently and repeated neurological assessment performed if an epidural catheter is used for repeated injections or for a continuous infusion of local anaesthetic. Neuroradiological examination should be carried out promptly if an epidural haematoma is suspected and surgical decompression performed without delay if the diagnosis is confirmed.