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D Zaric

Publications and source records attributed to D Zaric.

16 recordsLinked to original sources
PubMed1996

The effect of continuous epidural infusion of ropivacaine (0.1%, 0.2% and 0.3%) on nerve conduction velocity and postural control in volunteers.

BACKGROUND: Continuous epidural infusions of local anaesthetics have become increasingly popular in postoperative pain treatment, especially as they permit early mobilisation. Ropivacaine is a promising new agent which induces more pronounced sensory than motor blockade. This study was focused on the influence of continuous epidural infusion of ropivacaine on impulse conduction in large nerves (by measurement of F and H latencies), and on the subjects' ability to maintain postural control during mobilisation. METHODS: Healthy male volunteers received 0.1%, 0.2% or 0.3% ropivacaine, and bupivacaine 0.25% was used as reference. A bolus epidural injection of 10 ml of the drug, at L2/3 level, was followed by continuous infusion at 10 ml/h for 21 h. Motor blockade was assessed by mechanical measurements of force during big toe flexion and by recording of F latency. Sensory blockade was monitored by pin-prick and Thermotest methods, and by H latency recording. The subjects' ability to perform a postural test was evaluated by posturography. RESULTS: The F and H latencies became prolonged/abolished dose-dependently. With ropivacaine, F latency recovered significantly later than motor function (P = 0.0002), and H latency recovered later than normal pin-prick perception (P = 0.0006). However, the duration of partial blockade of thermoperception was comparable to that of H latency prolongation. Posturographically, the subjects receiving 0.1% ropivacaine differed significantly from all others (P < 0.001) in that they were able to maintain postural control during the infusion. The recovery period after termination of infusion was significantly shorter with ropivacaine than with bupivacaine for all measured variables. CONCLUSION: Recovery of postural control with 0.2% and 0.3% ropivacaine is significantly faster than with bupivacaine 0.25%. H latency recording allows detection of epidural blockade intensity that does not prevent subjects from performing postural tests.

Adult↗
PubMed1995

Pharmacokinetics of ropivacaine and bupivacaine during 21 hours of continuous epidural infusion in healthy male volunteers.

The aim of the present study was to evaluate the pharmacokinetics of ropivacaine and to compare the results with those of bupivacaine during prolonged epidural infusion. Ropivacaine 1, 2, or 3 mg/mL (0.1%, 0.2%, or 0.3%), bupivacaine 2.5 mg/mL (0.25%), or placebo (sodium chloride 0.9%) was given randomly and in a double-blind manner to five parallel treatment groups (37 healthy volunteers) as a continuous epidural infusion for 21 h. A 10-mL epidural bolus dose was first given, and the epidural infusion was started immediately afterward. The subjects received 10 mL/h corresponding to infusion rates of 10, 20, or 30 mg/h ropivacaine and 25 mg/h bupivacaine, respectively. Peripheral blood samples for measurements of ropivacaine or bupivacaine were taken during a 25-h period. The total plasma concentration increased continuously but seemed to reach a plateau (C5-10h) after approximately 5 h infusion, remaining fairly constant up to approximately 10 h after the start of administration. The C5-10h values were proportional to the dose of ropivacaine and were estimated as 0.3, 0.6, and 0.9 mg/L, and for bupivacaine as 0.7 mg/L. During the subsequent infusion the plasma concentration increased, with maximum plasma levels at the end of the infusion and with corresponding values of 0.4, 0.9, 1.2, and 0.9 mg/L. The highest individual plasma concentration was 1.7 mg/L (20 mg/h), and no patient showed signs of toxic systemic plasma levels. The free concentrations also increased continuously during the infusion. The free fraction was independent of the dose (6.1% for ropivacaine and 4.8% for bupivacaine).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

F response and H reflex for monitoring nerve block during epidural analgesia with ropivacaine.

The effect of a single epidural injection of ropivacaine on the motor and sensory function controlled from the L5/S1 level was investigated in 28 male volunteers. Concentrations of 1%, 0.75%, or 0.5% ropivacaine, 20 mL, administered at the L2/3 level were studied. Motor function was assessed quantitatively (measurement of muscle force by mechano-transducers), and sensory function by the pinprick method. In addition, F response and H reflex, tests which measure the conduction velocity in the central parts of peripheral nerves, were used. Epidural ropivacaine caused dose-dependent prolongation of the latencies of both these variables. F response latency recovered significantly later than motor function measured by mechano-transducers in the two lower concentration groups. H reflex latency recovered significantly later than sensory function assessed by the pinprick method in all three concentration groups. The time needed for recovery of F and H latencies was not significantly longer than the time from epidural injection to mobilization. At the time when the subjects could go through the mobilization procedure, 12 of 28 subjects were not completely recovered. In 5 of these 12 subjects, the H reflex latency was persistently prolonged at the end of the investigation, long after the subjects felt "normal" again. On follow-up recordings 5 mo later, the baseline latency had been regained in all five subjects. We conclude that F response and H reflex latencies are good indicators of the inhibition of nerve impulse conduction induced by epidural analgesia.

Adult↗
PubMed1993

Blockade of the abdominal muscles measured by EMG during lumbar epidural analgesia with ropivacaine--a double-blind study.

A single shot of 20 ml of 1%, 0.75% or 0.5% ropivacaine was administered epidurally (at L2/3 level) to 30 volunteers, in a double-blind manner. The blockade of the rectus abdominis muscle was measured quantitatively by registration of the average rectified electromyographic signal (AREMG) at the T7, T9 and T11 motor segmental levels and with a qualitative test for blockade of the rectus abdominis muscle (the so-called RAM test). The maximal cranial spread of analgesia, evaluated by the pin-prick method, was not significantly different for the three concentrations (T8-T10 dermatome; median value). The intensity of motor blockade, measured by the AREMG method, increased progressively from the T7 segment and caudally with all three concentrations. The blockade was partial (i.e. 85-25% of baseline AREMG activity was present at its maximum) in all subjects. When the effect of the three concentrations of ropivacaine was compared at the same segmental level, the intensity and duration of maximal motor blockade seemed to be dose-dependent, but the difference was not statistically significant. The total duration of motor blockade was shorter with the 0.5% solution than with the higher concentrations. The AREMG method gave a more exact and graded picture of blockade of the rectus abdominis muscle than the RAM test. The duration of sensory blockade did not outlast motor blockade at any level. In half of our subjects the maximal spread of sensory blockade was either equal to or higher than the spread of partial motor block. In the other half, this relationship was reversed--the maximal cranial level of partial motor block was 1-4 segments higher than the maximal level of analgesia.

Abdominal Muscles↗
PubMed1991

Sensory and motor blockade during epidural analgesia with 1%, 0.75%, and 0.5% ropivacaine--a double-blind study.

Levels of sensory (pinprick) and somatic motor blockade were measured in a double-blind study of 30 volunteers given single epidural injections of 1%, 0.75%, and 0.5% ropivacaine. Onset of analgesia was rapid with all concentrations (7-10 min). Maximal levels of analgesia were established 60 min after injection, with no significant differences in the maximal median cephalad spread. Duration of analgesia at the T-12 level and total duration were significantly longer with 1% and 0.75% than with 0.5% ropivacaine. Motor blockade was assessed by a quantitative method (measurements of isometric muscle force) and a qualitative method (modified Bromage scale). Onset of motor blockade measured by the quantitative method was significantly slower with 0.5% ropivacaine than with the higher concentrations. Maximal muscle weakness occurred 1-1.5 h after injection with all three concentrations. With increase in ropivacaine dose from 100 to 200 mg, the intensity and duration of motor blockade increased. Muscles involved in knee extension were blocked most, those of plantar flexion least. Recovery of motor function, assessed by the above-mentioned quantitative method, occurred simultaneously with the recovery of pinprick perception. Motor blockade registered by Bromage scale showed a slower onset for 0.5% ropivacaine than for the higher concentrations. Mean durations of grade 1 and 2 block were longest for the 1% solution. Motor blockade described by the Bromage scale showed only the first part of the regression phase. Full recovery of muscle strength (Bromage scale = 0) was attained 1.5-2.5 h earlier than assessed by the quantitative method. No adverse effects were registered.

Adult↗
PubMed1988

Postoperative cerebrovascular accidents in general surgery.

In a prospective study of postoperative complications, strokes occurred in 6 out of 2463 patients (0.2%) who underwent non-cardiac, non-carotid artery surgery. The patients who experienced cerebrovascular accidents, including three cases of transient ischemic attack, were significantly older than the rest of the group (mean age 79 years versus 65 years) and had manifestations of atherosclerosis in at least one organ preoperatively. Significant predictors of risk for postoperative cerebrovascular accidents were previous cerebrovascular disease, heart disease, peripheral vascular disease, and hypertension. Cerebrovascular accidents occurred late in the postoperative period, 5-26 days after surgery, and were not directly related to surgery and anesthesia. They were more frequent after acute than after elective operations. Precipitating factors for some of the stroke incidents were rapid atrial fibrillation and postoperative dehydration.

Adult↗
PubMed1987

[Sleep apnea].

Explore the source record for details and available documents.

Humans↗
PubMed1986

Perivascular axillary block VII: the effect of a supplementary dose of 20 ml mepivacaine 1% with adrenaline to patients with incomplete sensory blockade.

Perivascular axillary blockade was performed on 233 patients with the aid of a catheter technique. All patients received a primary injection of 50 ml of mepivacaine 1% with adrenaline. Sensory blockade was evaluated 20, 30 and 40 min after injection, and a complete sensory blockade was found in 90 (39%), 131 (57%) and 146 (63%), respectively. The blockade effect of a supplementary perivascular injection of 20 ml of the same agent was investigated on the remaining 87 blockades, which could be divided into three categories: blockades which at 20 min showed lack of analgesia in several cutaneous segments of the hand (34 patients); blockades which at 30 min showed a total lack of sensory blockade within a limited area (29 patients); and blockades which at 40 min showed signs of blockade of all cutaneous segments, but one or several segments were not blocked with an intensity compatible with surgery (24 patients). Blockades of categories 1 and 2 were at 20 and 30 min, respectively, randomly allocated to control or to perivascular supplementation groups, while blockades of category 3 all had supplementation at 40 min. Sensory blockade was reevaluated 10 and 20 min after group allocation, and it was found that perivascular supplementation had no significant effect on the sensory blockade in category 1 and 2, while 68% of the blockades in category 3 improved to a complete blockade.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Halothane hepatitis in a prospective study of postoperative complications.

In a prospective study comprising 2609 consecutive surgical patients, of whom 1166 were anesthetized with halothane, four cases of hepatitis were encountered. The incidence of hepatitis among those who received halothane was 1:292 in our material. The high incidence may be explained by the recognition of milder forms of hepatitis and by the selection of the series (over 40 years). Serum alanine aminotransferase should be investigated in all patients with postoperative pyrexia of unknown origin if mild forms of halothane hepatitis are to be discovered. The patient's history should be carefully examined for previous postoperative pyrexia of unknown origin following halothane anesthesia, in which case other anesthetics should be chosen.

Aged↗
PubMed1982

Capillary microscopy of the nail fold in patients with psoriasis and psoriatic arthritis.

The Capillary characteristics of the nail fold area were examined and compared by capillary microscopy in 31 patients with psoriasis (PS) and 34 patients with psoriatic arthritis (PA). 70 healthy persons served as controls. Significantly shorter mean capillary loop lengths and characteristic morphological capillary changes were found both in patients with PS and in patients with PA as compared to the controls. The number of hemorrhages and sluggishness of blood flow was more pronounced in both groups of patients as compared to the control group, but only significantly so in patients with PA. The only significant difference between the PS and the PA groups was a higher subpapillary plexus visibility (SPV) index in the latter. It is concluded that most of the capillary changes demonstrable in patients with PA are clinical manifestations of PS. The difference in the SPV index, however, warrants a follow-up study to elucidate whether patients with PS and a high SPV index are likely to develop arthritis.

Arthritis↗
PubMed1981

Capillary microscopy of the nailfold in psoriatic and rheumatoid arthritis.

The nailfold capillaries of 35 patients with psoriatic arthritis and 30 with rheumatoid arthritis were studied by capillary microscopy and the findings compared. Seventy healthy subjects served as controls. The pronounced subpapillary plexus visibility, greater number of vessels and their elongation are indicative of rheumatoid arthritis, while shorter, fewer capillaries and especially characteristic psoriatic capillaries, when present, suggest psoriatic arthritis. Sluggish blood flow, higher number of hemorrhages and higher subpappillary plexus visibility are common to both patient groups as opposed to the controls.

Arthritis↗
PubMedDate not supplied

The effect of continuous lumbar epidural infusion of ropivacaine (0.1%, 0.2%, and 0.3%) and 0.25% bupivacaine on sensory and motor block in volunteers: a double-blind study.

BACKGROUND AND OBJECTIVES: In animal studies, ropivacaine has shown more pronounced sensory block than motor block, which makes it an interesting drug for postoperative pain relief. The aim of this study was to investigate the dose response of sensory and motor block during continuous epidural infusion of 0.1, 0.2, or 0.3% ropivacaine in volunteers in a double-blind manner. Bupivacaine 0.25% and isotonic saline were used as reference and control, respectively. METHODS: Each treatment group consisted of eight healthy men. After a bolus dose of 10 mL at the L2-L3 interspace, the solution in question was infused at 10 mL/h for 21 hours. Sensory block was evaluated by the pinprick, light touch, and Thermotest methods. Motor block was measured by the Bromage scale, by average rectified electromyography in abdominal muscles, and by mechanical measurement of isometric muscle force in the lower extremities. Mobilization of the subjects was attempted throughout the investigation. RESULTS: The number of blocked dermatomes (evaluated by pinprick) with 0.1% ropivacaine was significantly smaller than with the other test solutions (P = .002-.0008). Motor block was minimal with 0.1% ropivacaine, so that all subjects could be mobilized; it was moderate with 0.2 and 0.3% ropivacaine and most intense with 0.25% bupivacaine. The regression phase was significantly shorter with all three concentrations of ropivacaine than with bupivacaine (P < .01). CONCLUSIONS: Ropivacaine 0.1% produced limited analgesia and minimal motor block, so that ambulation was possible throughout the investigation. With 0.2 and 0.3% ropivacaine, analgesia was more extensive, and motor block was considered moderate. Ropivacaine 0.2% should be evaluated for future postoperative pain treatment.

Adult↗
PubMedDate not supplied

Evaluation of epidural sensory block by thermal stimulation, laser stimulation, and recording of somatosensory evoked potentials.

BACKGROUND AND OBJECTIVES: The existence of differential sensory block during epidural analgesia has been confirmed by some authors and disputed by others. This study attempts to elucidate this issue by using quantitative methods for evaluation of sensory block. METHODS: A single epidural injection of 20 mL 0.5% bupivacaine with epinephrine was administered at the L1-T12 level in 11 male volunteers. Sensory block was evaluated by two qualitative (pinprick and light touch) and two quantitative methods (thermal stimulation with Thermotest [Somedic, Stockholm, Sweden] and argon laser stimulation). For measurement of motor block in the lower extremities and in the rectus abdominis muscle, quantitative methods were used. Sensory block was also assessed by somatosensory evoked potentials recorded during electrical and laser stimulation at the most cranial analgesic dermatome (loss of sharpness in pinprick perception) and the anesthetic dermatome L2 (loss of light touch perception). RESULTS: The zone of anesthesia was smaller than the zone of any other investigated variable. The cranial spread of analgesia and motor block was lower than that of laser-assessed block. Partial block of laser perception and thermal perception lasted longer than analgesia and motor block. No consistent segmental or temporal differences were found between the Thermotest and laser methods. During epidural block, prolongation of latencies and reduction in amplitudes of somatosensory evoked potentials produced at the most cranial analgesic dermatome did not differ significantly from those produced at the anesthetic dermatome. CONCLUSIONS: No differential block of small nerve fibers was found during epidural analgesia by Thermotest and argon laser stimulation. Recording of somatosensory evoked potentials did not demonstrate significant difference between responses from the sites with most superficial and with most intense sensory block.

Adult↗