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Biomedical subjects

F Donati

Publications and source records attributed to F Donati.

At least 163 records · Page 9Linked to original sources
PubMed1989

Dose-response relationships for edrophonium and neostigmine as antagonists of moderate and profound atracurium blockade.

To measure the ability of neostigmine and edrophonium to reverse moderate and profound atracurium blockade, dose-response relationships were established for these reversal agents given at 1% and 10% twitch height recovery. Eighty-five ASA I and II adult patients received atracurium, 0.4 mg/kg, during a thiopental-nitrous oxide-enflurane anesthetic. Train-of-four stimulation was applied every 12 seconds, and the force of contraction of the adductor pollicis muscle was recorded. Edrophonium, 0.1, 0.2, 0.4, or 1 mg/kg; neostigmine, 0.005, 0.01, 0.02 or 0.05 mg/kg; or no reversal agent was given when there was either 1% or 10% recovery of the first twitch response. With profound blockade, the slope of the edrophonium dose-response relationship was significantly flatter (P less than 0.05) than that of neostigmine. The dose of neostigmine required to achieve 80% first twitch recovery (ED80) after 10 minutes was 0.013 +/- 0.003 mg/kg (mean +/- SEM) if given at 10% recovery, and 0.032 +/- 0.004 mg/kg if given at 1% recovery. The ED80 for edrophonium was 0.22 +/- 0.04 mg/kg and 1.14 +/- 0.33 mg/kg, respectively. These values corresponded to neostigmine:edrophonium potency ratios of 16.6 +/- 3.5 and 35.3 +/- 8.9 at 90% and 99% blockade respectively (P less than 0.006). We conclude that the relative potency of neostigmine is greater than that of edrophonium for antagonism of profound atracurium blockade.

Atracurium↗
PubMed1988

Cumulative dose-response with infusion: a technique to determine neuromuscular blocking potency of atracurium and vecuronium.

The ability of cumulative dose-response techniques to obtain accurate data is most likely limited by redistribution and elimination of the drug during the study period. Therefore the usefulness of these techniques would be improved by replacing the amount of drug lost. This hypothesis was assessed for the intermediate-duration neuromuscular blockers vecuronium and atracurium, and calculations were made based on a pharmacokinetic model with an effect compartment. Sixty patients received either single doses (SD) (n = 36), cumulative doses (CD) (n = 12), or CD of vecuronium or atracurium with an infusion (CDI) to replace eliminated or redistributed drug (n = 12). The force of contraction of the adductor pollicis muscle in response to train-of-four stimulation was measured and recorded. Linear regressions were obtained between the logit transformation of neuromuscular blockade at the adductor pollicis and log dose. The potencies obtained with all three methods were within 20% of each other. For vecuronium the ED90 was (mean +/- SE) 0.034 +/- 0.002 (SD), 0.037 +/- 0.003 (CD), and 0.036 +/- 0.003 mg/kg (CDI). For atracurium the ED90 was 0.175 +/- 0.009 (SD), 0.206 +/- 0.019 (CD), and 0.179 +/- 0.015 mg/kg (CDI). Calculated values corresponded well with measured values. The calculations predicted that the agreement between single- and cumulative-dose techniques would be improved if (1) the dose increment was increased, (2) the elimination half-life was increased above 20 minutes, or (3) an infusion was added.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Potency of atracurium and vecuronium at the diaphragm and the adductor pollicis muscle.

Train-of-four stimulation was applied to the ulnar and phrenic nerves in 18 adult patients anaesthetized with nitrous oxide and halothane in oxygen. The response of the adductor pollicis and the diaphragm were measured. Incremental doses of atracurium and vecuronium were given, with an infusion to replace drug lost by elimination or distribution. The mean (SEM) doses of atracurium associated with 50% and 90% depression of response to the first stimulation in the train-of-four (ED50 and ED90) were 90 (9) and 133 (10) micrograms kg-1 at the adductor pollicis, and 130 (9) and 245 (17) micrograms kg-1 at the diaphragm, respectively. The mean (SEM) ED50 and ED90 of vecuronium were 25 (2) and 38 (4) micrograms kg-1 at the adductor pollicis and 34 (3) and 58 (5) micrograms kg-1 at the diaphragm, respectively. The mean (SEM) ED50 ratios were 1.56 (0.16) for atracurium and 1.47 (0.16) for vecuronium. ED90 ratios were 1.93 (0.29) and 1.55 (0.17) for atracurium and vecuronium, respectively. It is concluded that both atracurium and vecuronium exhibit a similar degree of sparing of the diaphragm.

Adult↗
PubMed1988

The potency of pancuronium at the adductor pollicis and diaphragm in infants and children.

To measure the potency of pancuronium at the diaphragm and adductor pollicis in infants and children, train-of-four stimulation was applied to the ulnar and phrenic nerves under N2O-halothane anesthesia. The force of contraction of the adductor pollicis was measured and compared with the diaphragmatic electromyogram (EMG). Cumulative dose response curves were determined for pancuronium in 18 patients divided equally into three age groups: 0-1 yr, 1-3 yr, and 3-10 yr. The potency of pancuronium at both muscles decreased with increasing age (P less than 0.05), while the adductor pollicis:diaphragm potency ratio remained constant. The mean doses (+/- SEM) required to depress adductor pollicis first twitch responses by 90% (ED90) were 42 +/- 3.3 micrograms/kg in the 0-1-yr group, 47 +/- 4.2 micrograms/kg in the 1-3-yr group, and 62 +/- 4.1 micrograms/kg in the 3-10-yr group. Corresponding figures for the diaphragm were 70 +/- 4.3 micrograms/kg, 81 +/- 5.1 micrograms/kg, and 101 +/- 4.4 micrograms/kg, respectively. The ED90 ratios (diaphragm ED90/adductor pollicis ED90) in the three age groups were 1.69 +/- .07, 1.75 +/- .14, and 1.64 +/- .09, respectively. These results are consistent with similar rates of maturation of the diaphragm and the adductor pollicis muscles in infancy and childhood. Thus, train-of-four monitoring of the adductor pollicis is likely to overestimate the degree of neuromuscular blockade of the diaphragm in pediatric patients.

Aging↗
PubMed1988

Dose-response curves for succinylcholine: single versus cumulative techniques.

This study was performed to determine the potency of succinylcholine using the single-dose technique, and to test the ability of the cumulative dose technique for generating dose-response data. Thirty-eight adult patients received single doses (n = 18), cumulative doses (n = 10), or cumulative doses of succinylcholine with an infusion to replace metabolized drug (n = 10). During opiate-thiopental-nitrous oxide anesthesia the force of contraction of the adductor pollicis in response to train-of-four stimulation was measured and recorded. Linear regressions were obtained between the logit transformation of neuromuscular blockade and log dose. Similar potencies were obtained with single dose and cumulative dose with infusion techniques with an ED90 of 0.27 +/- 0.03 and 0.26 +/- 0.02 mg/kg (mean +/- SEM) respectively. However, cumulative dose without infusion significantly underestimated potency with an ED90 of 0.42 +/- 0.06 mg/kg (P less than 0.05 compared with the other two techniques). It is concluded that cumulative dose techniques can be accurately employed to determine the potency of succinylcholine if an infusion is utilized to compensate for eliminated drug. The data suggest that clinically used doses of succinylcholine (1.0-1.5 mg/kg) are equivalent to 3-5 times the ED90 and may explain the excellent intubating conditions provided by this drug.

Adult↗
PubMed1988

Potency of succinylcholine at the diaphragm and at the adductor pollicis muscle.

To quantify the differential effect of succinylcholine at the diaphragm and the adductor pollicis muscle, 10 patients were studied during halothane-nitrous oxide anesthesia. Train-of-four stimulation was applied to the ulnar and phrenic nerves. The force of contraction and the electromyographic response of the adductor pollicis were measured and compared with the diaphragmatic electromyogram. Then dose-response curves for both muscles were constructed using incremental doses of succinylcholine with an infusion to replace metabolized or redistributing drug. Linear regressions were obtained between the logit transformation of neuromuscular blockade at the adductor pollicis and diaphragm and the logarithm of the dose. The diaphragm was relatively resistant to succinylcholine. At 90% adductor pollicis block, the diaphragm was only (mean +/- SEM) 37 +/- 3% blocked. The diaphragm required 1.8 +/- 0.2 times as much succinylcholine as the adductor pollicis for an identical 90% block. The ED50 and ED90 values for succinylcholine at the diaphragm were 0.23 +/- 0.04 and 0.40 +/- 0.09 mg/kg, respectively. Corresponding values for the adductor pollicis were 0.14 +/- 0.01 and 0.21 +/- 0.02 mg/kg. The data indicate that the degree of adductor pollicis blockade might overestimate the intensity of diaphragmatic paralysis.

Anesthesia, Inhalation↗
PubMed1987

Accelerated onset and delayed recovery of d-tubocurarine blockade with pancuronium in infants and children.

The effect of age on the onset and duration of action of a d-tubocurarine (DTC) neuromuscular blockade with and without pancuronium priming in children was examined. Sixty ASA physical status I or II patients in three age ranges (0-1 yr, 1-3 yr and 3-10 yr) were anaesthetized with thiopentone, halothane and nitrous oxide. Each patient received either a single paralyzing dose of DTC 0.4 mg.kg-1, or DTC 0.36 mg.kg-1 preceded three minutes earlier by pancuronium 0.007 mg.kg-1. Evoked force of contraction of the adductor pollicis was measured using train-of-four stimulation applied every 12 sec. Time to 90 per cent first twitch depression after a single dose of DTC increased with increasing age (r = 0.65, p less than 0.01), and was 1.6 min (SEM +/- 0.3) in the 0-1 yr group, 1.9 +/- 0.3 min (1-3 yr), and 5.2 +/- 1.2 min (3-10 yr). Time to ten per cent spontaneous recovery after single dose DTC was shorter in older individuals (r = 0.40, p less than 0.05), being 36.4 +/- 5.1 min in infants 0-1 yr, 30.6 +/- 4.6 min (1-3 yr), and 24.0 +/- 2.7 min (3-10 yr). Priming with pancuronium accelerated the onset significantly in all age groups with 90 per cent T1 depression occurring at 0.7 +/- 0.1 min (0-1 yr), 0.9 +/- 0.1 min (1-3 yr), and 2.1 +/- 0.6 min (3-10 yr). However, priming delayed recovery, especially in infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1987

Neostigmine, pyridostigmine and edrophonium as antagonists of deep pancuronium blockade.

To compare the ability of equipotent doses of neostigmine, pyridostigmine and edrophonium to antagonize intense pancuronium neuromuscular blockade, one hundred and twenty ASA physical status I or II patients scheduled for elective surgery received 0.06 mg.kg-1 pancuronium during a thiopentone nitrous oxide-enflurane anaesthetic. Train-of-four stimulation was applied every 12 s and the force of contraction of the adductor pollicis muscle was recorded. In the first 60 patients, spontaneous recovery was allowed until ten per cent of initial first twitch height. Then neostigmine (0.005, 0.01, 0.02 or 0.05 mg.kg-1), pyridostigmine (0.02, 0.04, 0.1 or 0.2 mg.kg-1), or edrophonium (0.1, 0.2, 0.4 or 1 mg.kg-1) was injected by random allocation. Dose-response relationships were established from the measurement of first twitch height (T1) ten minutes later. From these, neostigmine, 0.04 and 0.08 mg.kg-1 was found to be equipotent to pyridostigmine, 0.2 and 0.38 mg.kg-1, and edrophonium, 0.54 and 1.15 mg.kg-1, respectively. These doses were given by random allocation to the next 60 patients, but at one per cent spontaneous recovery. Neostigmine, 0.04 mg.kg-1, produced a T1 of 73 +/- 4 per cent (mean +/- SEM), and a train-of-four ratio (TOF) of 39 +/- 3 per cent. This was significantly greater than with pyridostigmine, 0.2 mg.kg-1 (T1 = 50 +/- 6 per cent; TOF = 25 +/- 3 per cent), and edrophonium, 0.54 mg.kg-1 (T1 = 54 +/- 3 per cent; TOF = 17 +/- 2 per cent).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Comparison of atracurium and succinylcholine for electroconvulsive therapy in a patient with atypical plasma cholinesterase.

Succinylcholine 2-5 mg or atracurium 10-15 mg were given on five separate occasions to a 24-year-old, 64 kg woman homozygous for atypical plasma cholinesterase who was undergoing electroconvulsive therapy (ECT). Atracurium blockade was reversed with atropine, 0.6 mg and edrophonium, 35 mg. Train-of-four stimulation was applied to the ulnar nerve and the force of contraction of the adductor pollicis muscle was recorded. Doses producing 90 per cent first twitch blockade were 2.5 and 15 mg for succinylcholine and atracurium respectively. The onset of action was 6 min for both relaxants, and time to 90 per cent first twitch recovery was 20 min for succinylcholine and 16 min for the atracurium-edrophonium combination. It is concluded that the use of atracurium in these patients does not offer marked advantages over small doses of succinylcholine.

Adult↗
PubMed1987

Onset and recovery of atracurium and suxamethonium-induced neuromuscular blockade with simultaneous train-of-four and single twitch stimulation.

Single twitch and train-of-four stimulation were applied at 0.08 Hz to each ulnar nerve and the force of contraction of the adductor pollicis was recorded during onset of and recovery from neuromuscular blockade by suxamethonium 1 mg kg-1 or atracurium 0.4 mg kg-1. Times to 90% first twitch blockade of train-of-four were (mean +/- SEM) 0.82 +/- 0.08 and 1.98 +/- 0.18 min for suxamethonium and atracurium, respectively, compared with times to 90% single twitch blockade of 1.00 +/- 0.07 and 3.35 +/- 0.37 min, respectively (P less than 0.05 in both cases). Apparent onset time also depended on how long train-of-four stimulation had been applied before injection of atracurium. The mode of stimulation had little effect on time to 10% recovery. The results are consistent with stimulation-induced augmentation in muscle blood flow, which increased delivery of the drug to the neuromuscular junction.

Adolescent↗
PubMed1987

Dose-response curves for edrophonium, neostigmine, and pyridostigmine after pancuronium and d-tubocurarine.

To determine the potencies of neostigmine, pyridostigmine, and edrophonium in reversing pancuronium and d-tubocurarine blockade, dose-response curves were established for first twitch height recovery and train-of-four ratio. One hundred and twenty ASA physical status I or II patients scheduled for elective surgery received either 0.06 mg/kg pancuronium or 0.36 mg/kg d-tubocurarine during a thiopental-nitrous oxide-enflurane anesthetic. Train-of-four stimulation was applied every 12 s, and the force of contraction of the adductor pollicis muscle was recorded. When first twitch height had recovered spontaneously to 10% of its initial value, neostigmine (0.005, 0.01, 0.02 or 0.05 mg/kg), pyridostigmine (0.02, 0.04, 0.1, or 0.2 mg/kg), or edrophonium (0.1, 0.2, 0.4 or 1 mg/kg) was injected by random allocation. Recovery was measured 10 min after the injection of the antagonist. First twitch ED50's were 0.013, 0.085, and 0.17 mg/kg after pancuronium, and 0.017, 0.11, and 0.27 mg/kg after d-tubocurarine, for neostigmine, pyridostigmine, and edrophonium, respectively. The ED50 for pyridostigmine and edrophonium obtained after d-tubocurarine was significantly larger (P less than 0.05) than that after pancuronium. The train-of-four dose-response curves were significantly flatter for edrophonium than for the other two agents, indicating a greater ability of edrophonium to antagonize fade at low doses. It is concluded that the potency of reversal agents may be different for different relaxants, and that potency ratios might depend upon the end-point chosen as full neuromuscular recovery.

Adult↗
PubMed1987

[Radiological changes in the nasal and paranasal cavities of patients having undergone laryngectomy].

A greater incidence of nasal sinus lesions is revealed in patients operated for laryngectomy than in healthy subjects. The radiographs of the paranasal sinuses of 49 patients laryngectomized for laryngeal cancer and 71 smokers, over 40, were compared. Thirty-six (73.5%) of the operated patients showed a reduction in the lucency of the sinuses (opacities, sinusitis, mucocele) and 21 (42.9%) inferior concha hypertrophy. In the control group 23 (32.4%) and 12 (16.9%) cases had the same lesions. Chi2 statistical analysis was performed on both groups. The results show a significant increase in lesions of the nasal sinuses in the group of operated patients. The reduction in the air flow through the nose and the sinus cavities during breathing seems to be the pathogenic mechanism responsible for such findings.

Adult↗
PubMed1986

Onset of pancuronium and d-tubocurarine blockade with priming.

The synergistic effect of pancuronium bromide (PCB) and d-tubocurarine (DTC) on the onset time of neuromuscular blockade was tested in 108 ASA physical status I and II adults anaesthetized with thiopentone, nitrous oxide and halothane. Either saline or a small (priming) dose (DTC, 0.04 mg X kg-1, or PCB, 0.007 mg X kg-1) was administered 3 min before a paralyzing dose of either DTC or PCB. The total dose of relaxant was equivalent to DTC, 0.4 mg X kg-1, or PCB, 0.07 mg X kg-1. Neuromuscular activity was measured using train-of-four stimulation applied every 12 s. Time to 50 per cent first twitch blockade was 63 +/- 4.6 s (mean +/- SEM) with DTC and 88 +/- 5.2 s with PCB (p less than 0.002). Times to 90 per cent blockade were not different between the two drugs (161 +/- 20 s and 141 +/- 21 s respectively). Priming a DTC blockade with either DTC or PCB or priming a PCB blockade with PCB produced an acceleration of less than 10 s at all levels of blockade. Compared with PCB alone, priming PCB blockade with DTC reduced the time to 50 per cent blockade to 71 +/- 4.5 s (p less than 0.02) and to 90 per cent blockade to 111 +/- 8 s (p less than 0.05). Priming did not affect the duration of action significantly, except in the case of PCB priming of DTC, where duration was increased from 39 +/- 4.4 to 57 +/- 4 min (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗