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Biomedical subjects

F Donati

Publications and source records attributed to F Donati.

195 records · Page 11Linked to original sources
PubMed1983

Long-term succinylcholine infusion during isoflurane anesthesia.

The characteristics of the neuromuscular blockade produced by prolonged succinylcholine infusion were compared in 40 patients anesthetized with either nitrous-oxide-isoflurane (0.75-1.50% inspired) or nitrous-oxide-fentanyl. Neuromuscular transmission was monitored using train-of-four stimulation and the infusion rate was adjusted to keep the first twitch at 10-15% of its control value. Initially, all patients exhibited a depolarizing-type block, and the infusion rates were similar in the isoflurane (61 micrograms . kg-1 . min-1) and fentanyl (57 micrograms . kg-1 . min-1) groups. Tachyphylaxis developed in both groups and correlated well with the onset of non-depolarizing (phase II) block. Both occurred sooner and at a lower cumulative dose in the isoflurane groups. After 90 min, infusion rates were similar in both groups (isoflurane: 107 micrograms . kg-1 . min-1, fentanyl;: 93 micrograms. kg-1 . min-1). After the infusion was stopped, the recovery of the train-of-four ratio was inversely related to the dose and duration of exposure to succinylcholine, and was slower with nitrous-oxide-isoflurane anesthesia. After 10 min of recovery, patients receiving isoflurane exhibited train-of-four ratios of 0.5 or less after 8.5 mg/kg succinylcholine and 103 min. Corresponding figures for fentanyl patients were 13 mg/kg and 171 min. The block in all 13 patients (eight with isoflurane, five with fentanyl) who did not recover spontaneously was antagonized successfully with atropine and neostigmine. It was concluded that with succinylcholine infusion of 90 min or less, isoflurane accelerates the onset of tachyphylaxis and phase II neuromuscular block without affecting succinylcholine requirements. These results, with isoflurane, were similar to those reported previously with enflurane or halothane.

Adult↗
PubMed1983

Potentiation of succinylcholine phase II block with isoflurane.

To determine the effect of isoflurane upon phase II block 20 patients were given succinylcholine by infusion at a rate which maintained the twitch tension of the adductor pollicis muscle at 10% of control for 2 to 4 h. The patients were assigned randomly to either nitrous-oxide-isoflurane (0.75-1.5% inspired) or nitrous-oxide-fentanyl for maintenance of anesthesia, and neuromuscular activity was monitored using train-of-four stimulation. Tachyphylaxis to succinylcholine was observed in both groups but this was followed, in the isoflurane group but not in the fentanyl group, by a decrease in succinylcholine requirement. This decrease was related to the extent of phase II block present. It is concluded that isoflurane potentiates succinylcholine phase II block although the mechanisms involved are not necessarily the same as in the potentiation of nondepolarizing neuromuscular blocking drugs.

Adult↗
PubMed1983

Twitch depression and train-of-four ratio after antagonism of pancuronium with edrophonium, neostigmine, or pyridostigmine.

During N2O-O2-halothane anesthesia pancuronium (3 mg/70 kg) was antagonized with neostigmine (2.5 or 5 mg/70 kg), pyridostigmine (10 or 20 mg/70 kg), or edrophonium (50 or 100 mg/70 kg) in 36 human subjects (6 in each group). Reversal was attempted at 10% spontaneous recovery of muscle twitch, which was measured using train-of-four stimulation. When first twitch tension was less than 70% of the control it was found that for the same tension, the train-of-four ratio was greater with edrophonium than with neostigmine, and greater with neostigmine than with pyridostigmine. It was concluded that the three antagonists have different mechanisms of action. In comparison with neostigmine, edrophonium is more and pyridostigmine is less effective at presynaptic (or fade) receptors.

Adolescent↗
PubMed1982

Effect of enflurane and fentanyl on the clinical characteristics of long-term succinylcholine infusion.

The characteristics of the neuromuscular block produced by prolonged succinylcholine infusion were compared in 40 patients anaesthetized with either nitrous oxide with enflurane (1-2 per cent inspired) or nitrous oxide and fentanyl. Neuromuscular transmission was monitored using train-of-four stimulation and the infusion rate was adjusted to keep the first twitch at 10-15 per cent of its control value. Initially, all patients, exhibited a depolarizing-type block all twitches of the train-of-four being roughly the same size, and the infusion rates were similar in the enflurane (54 microgram X kg-1/min) and the fentanyl (58 microgram X kg-1/min) groups. Tachyphylaxis developed later in both groups and correlated well with the onset of phase II block (dual block). This occurred sooner and at a lower cumulative dose in the enflurane group. Fourth to first twitch ratios decreased to 50, 25 and 0 per cent in 31, 46 and 59 minutes in the enflurane group, at cumulative succinylcholine doses of 2.2, 3.2 and 4.2 mg X kg-1 respectively. Corresponding figures for the fentanyl group were 52, 73 and 86 minutes, with dose of 3.4, 5.0 and 5.9 mg X kg-1. Infusion rates increased markedly after establishment of dual block, but were similar with enflurane (0.99 mg X kg-1/min) and fentanyl (1.12 mg X kg-1/min). Ten minutes after stopping the infusion fourth to first twitch ratios failed to reach 50 per cent in most patients given enflurane who had received more than 6 mg X kg-1 succinylcholine over more than 90 minutes. Corresponding figures for fentanyl patients were 13 mg x kg-1 and 150 minutes. The block in all 15 patients (9 enflurane, 6 fentanyl) who did not recover spontaneously was successfully antagonized with atropine and neostigmine.

Adult↗
PubMed1982

Antagonism of pancuronium in renal failure: no recurarization.

Neuromuscular transmission was measured using train-of-four stimulation, during and after anaesthesia, in 20 patients with end-stage renal failure. Neuromuscular blockade was provided with pancuronium in single doses of either 3 or 6 mg per 70 kg, and antagonized at 10% recovery with atropine and neostigmine 2.5 mg per 70 kg. Reversal was followed by progressive recovery of muscle twitch in every patient during the 3 h of the study. Recovery was more rapid after the smaller dose of pancuronium and was inversely correlated with the duration of blockade. It is concluded that, when pancuronium is antagonized with neostigmine in patients with renal failure, neuromuscular transmission recovers without evidence of recurarization. However, when large doses of pancuronium are antagonized with neostigmine 2.5 mg, recovery may be insufficient to ensure normal ventilatory function.

Adult↗
PubMed1981

Controlled succinylcholine infusion in a patient receiving echothiophate eye drops.

A 69 year old man receiving echothiophate eye drops for glaucoma was given a controlled infusion of succinylcholine during elective surgery for incisional hernia. Neuromuscular blockade was assessed by the measurement of the force of contraction of the adductor pollicis muscle. Only 9.5 mg succinylcholine were required for tracheal intubation and 1.1 mg/min for maintenance. When the infusion was stopped, recovery of neuromuscular transmission was rapid and uneventful. Plasma cholinesterase activity was 62 per cent below normal, but the enzyme was qualitatively normal. Thus, muscle relaxation can be achieved safely with a succinylcholine infusion in patients with decreased plasma cholinesterase activity if neuromuscular function is closely monitored.

Aged↗
PubMed1976

A descriptive method for automatically analysing uterine forces during labor.

In recent years many authors have considered evaluation of uterine contractility by means of analysis of amniotic fluid pressure variations. The reason for this is the introduction in obstetrical management of equipment for the recording of amniotic fluid pressure variations which is a powerful facility for clinical investigation, particularly, if it is considered that previous research has been based upon clinical evaluations and measurements carried out by extra and intra-uterine manometers. Important results of these studies are the definitions of two labor indices, the Montevideo unit (defined as the sum of the maxima of the pressure signal of all uterine contractions during a time interval of ten minutes) and the Alexandria unit (which also takes into account the duration of the contraction:this unit corresponds to the Montevideo unit multiplied by the mean value of the duration of the considered contractions). It is very difficult, however, in fact almost impossible, to summarize the evaluation of labor as the only indes. Many parameters which characterize the shape, frequency and tone of contraction patterns, may be themselves important and could indicated the presence of pathological elements. At present it is not well known which parameters are useful. Since many different sets of parameters can be chosen to characterize the signal, the first point is to determine which is more important clinically. The aim of this paper is to study a procedure of intrauterine pressure signal analysis, which allows the description of uterine contraction by a set of parameters that is interesting for research purposes during labor and suitable for continuous monitoring. The set of parameters was chosen in order to repeat quantitatively the qualitative analysis which a physician can make by a simple inspection of the pressure signal oscillogram. Visual examination of the tocograph results is a clumsy means for evaluating labor performed by an experienced physician. It may appear that the pressure starts "suddenly" (or not) to increase and rises "quickly" (or "slowly"), then it maintains "high" (or "low") mean values for a "long" (or "short") time, with "smooth" (or "irregular") behaviour, then it decreases "quickly" (or slowly, until "suddenly" (or "smoothly") it reaches its basal level, whd the beginning of another uterine contraction is "long" (or "short", during this time the pressure is "almost" constant (or has a "drift" and/or presents "many irregularities"). Therefore the 25 chosen parameters replace quantitatively the above qualitative evaluations. These parameters are not put forward to indicate directly the presence of pathological facttor, but summarize all the interesting clinical aspects of the contraction waveform for research and monitoring purposes. The parameters are extracted using a pattern recognition algorithm based on a structural representation of the contraction (Tables I, II, V)...

Computers↗
PubMedDate not supplied

Complications of orthotopic liver transplantation: imaging findings.

Orthotopic liver transplantation has become the major treatment for end-stage chronic liver disease and for severe acute liver failure. Despite the improvement in survival due to advances in organ preservation, improved immunosuppressive therapy agents, and refinement of surgical techniques, there are significant complications after liver transplantation. These complications mainly include biliary strictures, stones, and leakage; arterial and venous stenoses and thromboses; lymphoproliferative disorders; recurrent tumors; hepatitis virus C infection; liver abscesses; right adrenal gland hemorrhage; fluid collections; and hematomas. The diagnosis of acute rejection, one of the most serious complications after liver transplantation, is established with graft biopsy and histologic study. The role of imaging methods consists of excluding the other complications, which can have clinical signs and symptoms similar to those of acute rejection. This pictorial essay describes imaging findings of the various complications after liver transplantation and focuses on their radiologic diagnosis. Knowledge and early recognition of these complications with the most suitable imaging modality are crucial for graft and patient survival.

Humans↗
PubMedDate not supplied

Combination of interventional therapies in hepatocellular carcinoma.

Many interventional techniques aimed at achieving nonsurgical ablation of hepatocellular carcinoma have been developed and clinically tested over the last decade. Percutaneous image-guided therapies such as ethanol injection and radiofrequency thermal ablation provide an effective means for treating hepatocellular carcinoma lesions smaller than 3 cm, but do not ensure successful ablation of larger tumors. In view of the limitations of available interventional therapies, there is currently a focus on a multimodality strategy for the treatment of large hepatocellular carcinomas. Combination of transcatheter arterial chemoembolization and ethanol injection overcomes the weakness of each of the two procedures, enhancing local therapeutic effect and long-term survival. More recently, a new technique for single-session ablation of large hepatocellular carcinoma lesions has been devised by combining transcatheter hepatic arterial balloon occlusion/embolization and radiofrequency treatment. This combined approach substantially increases the thermal necrosis volume that can be created with respect to the conventional radiofrequency technique, as a result of the reduction of heat loss caused by convection. In a pilot multicentric clinical trial performed in 62 patients, successful ablation of hepatocellular carcinoma lesions ranging 3.5-8.5 cm in diameter was achieved in 82% of cases in the absence of major complications. This new technique seems to have the potential to replace other interventional methods for the treatment of large hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Epigastric sensations as an unusual manifestation of adult absence epilepsy.

We report the case of a 39-year-old woman with onset of daily epigastric sensations associated with brief episodes of unresponsive blank stare, which have been interpreted as complex partial seizures with occasional secondary generalisation. Phenytoin as monotherapy and in combination with valproate had not been effective. During video-EEG we recorded typical absences with brief 3 second spike, and slow-wave discharges of up to 5 seconds, which were recognized by the patient herself. All absences were preceded by epigastric sensations. There was no indication of focal epilepsy. Monotherapy with valproate substantially decreased the frequency of the absences. In conclusion, this case is peculiar for several reasons: 1) late onset of absence epilepsy, 2) epigastric sensation at onset of absence seizures, 3) recognition of brief "phantom" absences and 4) presumable adverse effects of phenytoin.

Adult↗