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Biomedical subjects

S Reiz

Publications and source records attributed to S Reiz.

At least 37 records · Page 2Linked to original sources
PubMed1990

Systemic, pulmonary and renal haemodynamic effects of large intravenous doses of high and low osmolar contrast media. An investigation in the pig of ratio 1.5 and ratio 3 media.

The central, peripheral and renal haemodynamic effects of intravenous infusion (1 ml/s) of large doses (4 ml/kg body weight) of non-ionic (iohexol) and ionic (metrizoate and ioxaglate) contrast media were studied in 24 anaesthetized pigs. All contrast media showed marked haemodynamic effects with an increase of mean right atrial pressure, mean pulmonary arterial pressure, mean pulmonary occlusion pressure, cardiac output and stroke volume. The response of the pulmonary circulation to contrast media was a fall rather than a rise in pulmonary vascular resistance. No significant changes were detected in the renal circulation after infusion of contrast media.

Animals↗
PubMed1989

Bupivacaine: a safe local anesthetic for wrist blocks.

Seventy-one patients having minor hand surgical procedures under wrist block anesthesia were studied, with the goal of identifying a possible neurotoxic potential of bupivacaine when used according to standard clinical practice. This drug was compared with lidocaine at equipotent analgesic concentrations (bupivacaine: 5 mg/ml; lidocaine: 20 mg/ml) by use of a double-blind randomized protocol. At postoperative follow-up, four (5.6%) patients had new neurologic symptoms. Mechanical factors, e.g., nerve manipulation during surgery, or nerve trauma during performance of the block, were identified in three patients. In the remaining patient, anesthesia was induced with lidocaine, and no cause could be identified. It was concluded that bupivacaine, when used in clinical concentrations, is not associated with an increased incidence of neural complications.

Bupivacaine↗
PubMed1989

Comparison of hemodynamic, electrocardiographic, mechanical, and metabolic indicators of intraoperative myocardial ischemia in vascular surgical patients with coronary artery disease.

To compare mechanical, electrocardiographic, and metabolic indices of myocardial ischemia, the cardiokymogram (CKG), the V5 ECG, left anterior descending coronary artery territory lactate extraction, and pulmonary capillary wedge pressure (PCWP) were measured in 53 vascular surgical patients with coronary artery disease. Measurements were performed preoperatively and at four specific intraanesthetic intervals: after tracheal intubation, before surgery, and 10 and 30 min after incision. Measurements and sampling sequence took 5-7 min, and therapy for the probable cause of ischemia was instituted following completion of this sequence. Myocardial ischemia was defined as type II or III CKG, 0.1 mV or greater horizontal or downsloping depression of V5 ECG ST segment, 0.2 mV or greater elevation of V5 ECG ST segment, or myocardial lactate production. Thirty-nine patients (74%) had a total of 89 episodes of myocardial ischemia. Seventy-four episodes (83%) were detected by the CKG, 31 (44%) were evident on the ECG, and 13 (15%) by evidence of lactate production. The concordance among the indices of myocardial ischemia was poor. Patients with an abnormal preoperative ECG experienced a greater number of ischemic episodes (P less than 0.001). Elevation of PCWP or the presence of A-C or V-waves greater than 5 mmHg above the mean did not individually reflect ischemia reliably. Intraoperative myocardial ischemia is common in vascular surgical patients and is most sensitively detected by ventricular wall motion abnormality.

Aged↗
PubMed1989

Cardiotoxicity of ropivacaine--a new amide local anaesthetic agent.

Anaesthetically equipotent doses of lidocaine, bupivacaine and a new bupivacaine-like local anaesthetic agent, ropivacaine, were injected into the left anterior descending coronary artery of pentobarbital-anaesthetized pigs. The aim was to study the cardiotoxicity of ropivacaine in relation to the two other drugs. A random, crossover, dose response study design was used. The following doses of the drugs were administered: lidocaine (L): 1,2,4,8 and 16 mg, bupivacaine (B): 0.25, 0.5, 1,2 and 4 mg and ropivacaine (R): 0.33, 0.66 1.33, 2.66 and 5.33 mg. Systemic haemodynamics, left ventricular dP/dT and a 12-lead electrocardiogram were recorded continuously during the study period. The drugs depressed cardiac contractility in relation to their local anaesthetic potency on the isolated nerve-4:3:1 (B:R:L). The prolongation of the ECG QRS-interval was regarded as a measure of electrophysiologic toxicity. Comparable prolongation of the QRS-interval was recorded after 2 mg of bupivacaine, 4.5 mg of ropivacaine and 30 mg of lidocaine. Thus, the electrophysiological toxicity ratio was 15:6.7:1 (B:R:L). Provided local anaesthetic potency data can be extrapolated from the isolated nerve preparation to regional anaesthesia in humans, ropivacaine appears to provide a greater margin of safety than bupivacaine, if inadvertently injected into the venous circulation.

Amides↗
PubMed1989

Anevac-D, a new system for close scavenging of anesthetic gases in dental practice.

Anevac-D, a new system for close scavenging of anesthetic gases in dental practice is described. It consists of a rubber nose mask surrounded by an outer rigid shell and a chin scavenger. A vacuum in the slot between the nose masks provides scavenging of gases escaping from the inner mask. Gases escaping from the mouth are evacuated mainly by the skin scavenger. The efficiency of this system was assessed in healthy volunteers using argon as a tracer gas. Mass spectrometry was used for measurement of inspired, expired, and scavenged gas concentrations. The scavenging efficiency of the complete system was around 80% and was not affected by poor patient cooperation. It decreased to about 65% when the chin scavenger was removed. The dentist's exposure was measured by sampling of argon in the breathing zone by a Saran system. The average 4-min exposure varied between 90 and 250 ppm depending on system configuration and patient cooperation. Patient acceptance and clinical applicability were judged good. It is concluded that the Anevac-D system provides excellent scavenging properties and exposure levels well within the official recommendations by the Swedish Board of Occupational Safety and Health.

Adolescent↗
PubMed1989

Pharmacokinetics and central haemodynamic effects of doxorubicin and 4'epi-doxorubicin in the pig.

The relationship between the cardiotoxicity and the haemodynamics/pharmacokinetics of clinical concentrations of doxorubicin and 4'epi-doxorubicin was studied. Twelve pigs were randomized to receive i.v. infusions of either drug of 50 mg/m2 over 3.0 min. Aortic, pulmonary arterial, coronary sinus and central venous plasma concentrations of the agents were determined until 180 min after the infusion. The V5 ECG, left ventricular dP/dT, aortic, pulmonary arterial and right atrial pressures were recorded continuously, cardiac output and coronary sinus blood flow were recorded intermittently. No haemodynamic changes were recorded after administration of either drug. Pharmacokinetic data indicated myocardial extraction, followed by myocardial release of both drugs. This release was higher after administration of 4'epi-doxorubicin than after doxorubicin, within the range 2-4 min and 20-40 min after the infusion. The tendency of greater myocardial release of 4'epi-doxorubicin may explain its lower cardiotoxicity.

Animals↗
PubMed1989

Coronary vasomotion during anesthesia.

The incidence of perioperative myocardial ischemia and associated cardiac complications in patients with coronary artery disease (CAD) varies widely, as reported in the literature. Much of the confusion and contradictions surrounding this issue can be attributed to differences in populations studied, study protocols, and techniques employed to diagnose myocardial ischemia and infarction. Data obtained in recent years have indicated that a large proportion of intraoperative myocardial ischemic events are unrelated to hemodynamic aberrations. Coronary vasospasm and blood flow redistribution have both been suggested as important mechanisms for ischemia during anesthesia and surgery in patients with CAD. These findings challenge our concepts of how ischemia might be prevented by maintaining systemic hemodynamics within "normal limits". They also emphasize the importance of establishing new and more sensitive methods to detect myocardial ischemia in the operating room and recovery area. This paper focuses on myocardial ischemia related to coronary vasomotion during anesthesia and surgery.

Anesthesia, General↗
PubMed1988

Cardiopulmonary hemodynamics and pharmacokinetics after hepatic intraarterial infusion of 5-fluorouracil (5-FU). An experimental study in the pig.

Reported 5-FU-induced cardiac side effects may be explained by drug-induced hemodynamic changes and/or by direct myocardial toxicity due to regional drug uptake. This question was studied in 11 animals given constant infusions and 6 animals given bolus 5-FU infusions into the hepatic artery. Six animals, which received normal saline infusion, served as controls. A second aim was to study possible pulmonary drug clearance. Aortic, pulmonary arterial, and coronary sinus plasma 5-FU concentrations were determined during constant and after the bolus infusions of 5-FU. The V5 ECG, aortic, pulmonary arterial, and right atrial pressures were recorded continuously, and cardiac output and coronary sinus blood flow were recorded intermittently in all animals. No significant alterations in hemodynamic variables were seen during constant infusion. After the bolus infusion, an increased arterio-mixed venous oxygen content difference was recorded. Pharmacokinetic data after 3-min infusions indicated pulmonary drug uptake and release; during constant infusions, the data indicated myocardial drug uptake. As there were no alterations in myocardial oxygen demand or supply or in systemic hemodynamics during this myocardial drug uptake, it is likely that the cardiotoxicity is related to the direct effects of the drug on cardiac myocytes.

Animals↗
PubMed1988

Peak torque and OBLA running capacity in male orienteers.

The isokinetic (30, 60, 120 and 180 degrees s-1) peak torque of m. quadriceps femoris and m. triceps surae, and the running velocity at the onset of blood lactate accumulation (VOBLA) were determined at three different occasions (November, April and September) during a year in 15 male élite orienteers. The amount and type of training for each individual was also registered. At the first test (November) there was no significant intra-individual correlation between peak torque of m. quadriceps and m. triceps surae. A negative correlation was found between VOBLA and peak torque of m. quadriceps at the lower velocities of angular motion, but not at the higher. The peak torque of m. triceps surae increased during the training period and decreased during the competition period back to the original level. Over the whole year the peak torque of m. quadriceps increased while no changes could be demonstrated within the two periods of the study. The running velocity at the onset of blood lactate accumulation increased during both training and competition periods. The changes in VOBLA were negatively associated with the changes in peak torque of m. quadriceps at 180 degrees s-1 during the training period. During the competition period the changes in VOBLA were, for the majority of the orienteers, negatively correlated to the ratio of quality:quantity running, i.e. to a high content of forest running.

Adult↗
PubMed1987

Effects of prenalterol on central hemodynamics and myocardial metabolism in experimental propoxyphene-induced shock.

The hemodynamic and cardiometabolic effects of prenalterol were evaluated in propoxyphene-induced circulatory shock in 10 pentobarbital-anesthetized pigs. Circulatory shock (i.e. a systolic arterial blood pressure below 60 mmHg (8 kPa) and/or a cardiac index of less than 2.0 1 X min-1 X m-2) was induced by intravenous propoxyphene chloride 15 mg X min-1. Circulatory shock occurred after 26 +/- 3 mg X kg-1 of propoxyphene. During continuous infusion of propoxyphene, consecutive doses of prenalterol 0.5, 1.0, 2.0 and 4.0 mg i.v. were injected with an interval between increments of 8 min. The maximum effect of prenalterol was seen following the 2 mg dose. Increases were observed in mean arterial blood pressure, cardiac index, stroke volume index, left ventricular stroke work index, right ventricular stroke work index, maximum rate of rise of ventricular pressure, and total body oxygen consumption. Decreases were observed in pulmonary artery occlusion pressure, mean right atrial pressure and systemic vascular resistance, whereas heart rate and pulmonary vascular resistance remained unchanged. The cardiometabolic parameters: coronary sinus flow, coronary vascular resistance, myocardial oxygen consumption and extraction, remained low. Due to profound vasodilation, normal perfusion pressures were not reestablished. In conclusion, prenalterol improved cardiac performance by a significant positive inotropic action. However, pure inotropic stimulation was not sufficient to counteract the circulatory shock state during severe propoxyphene intoxication.

Animals↗
PubMed1987

Cardiovascular effects of pentobarbital in pigs, and the lack of response to naloxone in pentobarbital induced circulatory failure.

The hemodynamic effects of pentobarbital were tested in an experimental model used for cardiovascular research. Anesthesia was induced with an i.v. bolus and maintained with a continuous infusion of pentobarbital. The cardiovascular performance was then evaluated at various pentobarbital plasma concentrations ranging from 25 to 100 mg X l-1. Optimal experimental conditions were found at plasma pentobarbital concentrations within the range 40-60 mg X l-1, as the animals were well anesthetized with intact hemodynamics or ECG. The method of continuous pentobarbital administration seems advantageous for experimental research. Circulatory impairment following pentobarbital overdose was not affected by naloxone.

Animals↗
PubMed1987

Increased monoamine metabolite concentrations and cholinesterase activities in cerebrospinal fluid of patients with acute stroke.

Twenty-one patients with acute brain infarction, 8 with transient ischemic attack and 20 controls were investigated for lumbar cerebrospinal fluid (CSF) monoamine metabolites and cholinesterases. The diseased patients were lumbar punctured on 2 occasions, mean Days 1 (0-3) and 5 (3-9) after debut of symptoms. Monoamine concentrations were determined by reverse phase liquid chromatography with electrochemical detection and the cholinergic enzymes were measured photometrically. Increased concentrations of 3-methoxytyramine (3-MT), homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HI-AA) and increased activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in lumbar cerebrospinal fluid was found in patients with acute brain infarction when compared to control values, while the levels of 3-methoxy-4-hydroxyphenylglycol (MHPG) were not altered. No change of any neurotransmitter metabolite concentration/enzyme activity were found between Day 1 and Day 5 in the diseased patients. These data suggest an increased release of these neurotransmitter markers from necrotic brain areas into the cerebrospinal fluid and/or altered barriers between blood, brain and CSF and/or a dysfunction of the arachnoid villi to clear substances from the CSF. We therefore concluded that CSF neurotransmitters may be useful as specific brain markers in acute stroke.

Acute Disease↗
PubMed1987

Fatigue and endurance of lower extremity muscles in relation to running velocity at OBLA in male orienteers.

At three occasions during a year, the ratio of contractional work (output)/integrated electromyographic activity (input), that is, CW/iEMG, was measured during repetitive maximum isokinetic manoeuvres for m. quadriceps and m. triceps surae in male elite orienteers. Running velocity at the onset of blood lactate accumulation (VOBLA), which was considered as a measure of running performance, and maximal oxygen uptake (VO2max) were analysed at each test. Type and amount of training were continuously registered. For m. quadriceps there was a decline in CW/iEMG during the first 30 manoeuvres, followed by an unchanged plateau level. In contrast, m. triceps surae showed a plateau level of virtually unaltered CW/iEMG ratio from the start to the end of the experiment. The differences might be explained by structural causes, but also by local muscle adaptation to training. The plateau level of CW/iEMG of m. quadriceps was positively correlated to VO2max. An increase in the plateau level of CW/iEMG was found for both tested muscle groups after the winter training period (mainly low intensity road running) when both VOBLA and VO2OBLA increased. During the competition period (mainly high intensity forest running), the whole group increased while some orienteers lowered their VOBLA. During this period, no changes in the plateau level of CW/iEMG of any muscle group or in VO2OBLA occurred. The changes in the plateau level of CW/iEMG might express local muscle adaptations to changes in running technique and aerobic/anaerobic demands during low intensity road running versus high intensity forest running.

Adult↗
PubMed1987

Postoperative confusion after anesthesia in elderly patients with femoral neck fractures.

Fifty-seven patients, all over the age of 64, with femoral neck fracture were randomized to receive epidural or halothane anesthesia to see if the anesthetic technique influenced the incidence of postoperative confusion. All patients were lucid on admission. Using the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-III) as criteria for confusion, we found that 44% of the patients developed confusion that correlated closely to a history of mental depression (P less than 0.01) and to the use of drugs with anticholinergic effect (P less than 0.005). There was no difference in the incidence of confusion between the two anesthetic groups. In patients given halothane, however, early postoperative hypoxemia was associated with confusion (P less than 0.05). Patients with confusion had significantly more postoperative complications and almost four times longer hospitalization times. It is concluded that anticholinergic medication and a history of mental depression are predominant risk factors for development of postoperative confusion and in this respect are more important than the anesthetic technique.

Aged↗
PubMed1986

Superoxide dismutase and catalase reduce infarct size in a porcine myocardial occlusion-reperfusion model.

We investigated if superoxide dismutase and catalase could reduce myocardial infarct size in an open chest occlusion-reperfusion model. Thirty pigs were used for the experiment. The left anterior descending artery was ligated for 60 min followed by a 5 h reperfusion period. After randomisation and blinding the two enzymes or placebo were injected into the left atrium as a bolus immediately before and at the end of the occlusion and as a continuous infusion over the first hour of the reperfusion period. The total dose for each enzyme was 8 mg/kg bw. Tetrazolium staining was used to determine infarct size. The study code was not broken until all calculations and exclusions had been made. Nine animals died from intractable ventricular fibrillation, most commonly during the occlusion. Another three were excluded for technical reasons. We found that superoxide dismutase and catalase reduced infarct size in relation to myocardium at risk from a mean of 89% to 63% (P less than 0.01). Initial plasma half life for the two enzymes after the bolus infusions were calculated to be 30 min.

Animals↗
PubMed1986

Influence of isoflurane on renal and intestinal vascular responses to stress.

Renal and intestinal vasoconstrictor responses elicited by either hypothalamic defence alarm area activation or stimulation of somatic and visceral afferents were studied in 17 cats. In part I, the circulatory adjustments during 2% (end-tidal) isoflurane plus 70% nitrous oxide in oxygen were compared with a medium-dose fentanyl in 70% nitrous oxide-oxygen sequence which was supplemented by diazepam. In part II, three end-tidal concentrations of isoflurane (1.4%, 2% and 3%) plus nitrous oxide in oxygen were evaluated before and after pre-treatment with droperidol 200 micrograms kg-1. During fentanyl-diazepam anaesthesia, intense vasoconstrictor responses with associated decreases in renal and intestinal blood flows were observed. Isoflurane 2% counteracted this reflex vasoconstriction, particularly in the renal vascular bed. The pressor and vasoconstrictor responses were suppressed by isoflurane in a dose-dependent fashion. After the administration of droperidol, the vascular beds were unaffected by noxious stimulation. It is concluded that isoflurane blunts stress-related vasoconstriction in a dose-dependent fashion, especially in the renal, but also in the intestinal, circulation. Droperidol adds to the vasodilatory effect of isoflurane.

Animals↗