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Biomedical subjects

R Chiolero

Publications and source records attributed to R Chiolero.

At least 37 records · Page 2Linked to original sources
PubMed1991

Oxidative metabolism of circulating granulocytes in adult respiratory distress syndrome.

Among the different mechanisms involved, polymorphonuclear leukocytes (PMNs) may play a central role in the pathogenesis of adult respiratory distress syndrome (ARDS). PMNs were evaluated in 15 patients with ARDS, in 21 at risk of developing ARDS (AR), and in 36 controls (C). Spontaneous and opsonized zymosan (OZ), phorbol myristate acetate (PMA), and F-Met-Leu-Phe (F-M-L-P)-stimulated oxygen radical production was measured by luminol- and lucigenin-enhanced chemiluminescence (CL). Spontaneous CL activity of PMNs from ARDS patients was significantly greater than that from the PMN control (luminol CL, 2.8 +/- 0.6 vs. 0.8 +/- 0.1 mV, p less than 0.001; lucigenin CL, 2.0 +/- 0.6 vs. 0.30 +/- 0.04 mV, p less than 0.001), and the CL value from AR patients (luminol CL, 1.3 +/- 0.2 mV, p less than 0.001 vs. C; lucigenin CL, 0.8 +/- 0.1 mV, p less than 0.001 vs. C) was found to be between the ARDS and C patients. The peak of PMA-stimulated CL occurred earlier and it was significantly higher in ARDS patients than in AR patients (p less than 0.05) and controls (p less than 0.001). When the CL response was elicited with F-M-L-P, no difference among the three groups was found. When stimulated with OZ, the peak CL generated by PMNs from ARDS patients was significantly depressed compared with controls (luminol CL, 26.7 +/- 1.8 vs. 40.9 +/- 2.3 mV, p less than 0.01; lucigenin CL, 5.0 +/- 0.4 vs. 7.4 +/- 0.5 mV, p less than 0.005) with a similar result being obtained from AR patients (luminol CL, 32.1 +/- 2.5 mV, p less than 0.01 vs. C). Plasma from ARDS and AR patients showed a defective opsonizing capacity, suggesting in vivo complement consumption in both patient groups. No correlation between the severity of hypoxemia, the cause of ARDS, the outcome, and the different PMN functions could be established. Our results are in agreement with a determinant role of PMNs in the development of ARDS. The opposite metabolic responses may explain both the pulmonary injury and the increased susceptibility to infections observed in patients at risk of or with ARDS.

Acridines↗
PubMed1991

Postoperative arrhythmias and risk factors after open heart surgery.

Cardiac arrhythmias were recorded during 24 hours in 40 consecutive patients requiring open-heart surgery, using continuous Holter monitoring. Most patients developed both supraventricular and ventricular arrhythmias. Complex ventricular arrhythmias were detected in 31 patients (78%) and 2 patients suffered an immediate postoperative myocardial infarction. The following risk factors were considered: age, sex, type of heart disease, preoperative left ventricular ejection fraction, cardiopulmonary bypass and aortic clamping duration, length of anesthesia, dopamine administration, and maximal level of CK and CK-MB. Only dopamine administration, even in low renal dose, was associated with the number and severity of ventricular arrhythmias.

Adult↗
PubMed1991

[Use of benzodiazepines in neurosurgical resuscitation].

Continuous intravenous sedation is often used during the intensive treatment of severe head injury. Hypnotic agents may prevent or treat the brief episodes of intracranial hypertension associated with nociceptive stimuli. However there is yet no clinical data in the literature showing beneficial effects of continuous sedation on intracranial pressure control or outcome in severe head injured patients. Sedation should be primarily administered to allow good conditions for intensive treatment. Benzodiazepines are sedatives with limited systemic side effects. Midazolam is very convenient because its short duration of action allows reasonable recovery time following prolonged administration. The abrupt reversal of sedation by means of specific antagonists may induce significant elevation of cerebral blood flow and intracranial pressure and should be avoided.

Barbiturates↗
PubMed1991

[Clinical use of propofol in neuroanesthesia].

Since Althesin was withdrawn from the market, and since Ledingham's report on the inhibitory effect of etomidate on cortisol secretion, anaesthesia in intracranial surgery has lacked an intravenous agent with a pharmacokinetic-dynamic profile making it a suitable alternative to the classic thiopental-isoflurane sequence. Propofol has been used experimentally in neuroanaesthesia for 4 years, and is now ready to be used on a routine basis in neuroanaesthesia. An induction dose of propofol decreases cerebral blood flow (CBF), cerebral metabolic rate for oxygen (CMR02), and intracranial pressure (ICP). Mean arterial pressure (MAP) is only moderately decreased if propofol is given as a mini-infusion instead of being given on a mg/kg basis. The intraoperative dosage is low (50-100 micrograms.kg-1 x min-1) due to the fact that intracerebral surgery is not painful. Recovery can thus be rapid. Propofol is used with the same agents or manoeuvres as those used with the thiopental-isoflurane sequence, i.e. lidocaine, fentanyl, esmolol, mannitol, steroids, hyperventilation and lumbar drainage in order to obtain the most relaxed brain and reduce the mechanical pressure exerted on the brain. Propofol can be used for all intracranial pathologies with may be one exception, when a cerebral aneurysm has to be clipped and vasospasm is present.

Anesthesia, Intravenous↗
PubMed1990

[Flumazenil and peroperative awakening in surgery of scoliosis].

Motor and sensory function must be assessed during surgery of scoliosis so as to avoid possible damage to the spinal cord. The intraoperative awakening by a specific benzodiazepine antagonist, flumazenil, was studied prospectively in 20 patients (mean age 17 years) undergoing surgery for severe scoliosis. Premedication consisted in 0.02 mg.kg-1 atropine and 0.15 mg.kg-1 midazolam. Anaesthesia was induced with a mean dose of 0.42 +/- 0.1 mg.kg-1 midazolam, 1.6 +/- 0.6 micrograms.kg-1 fentanyl and 0.1 mg.kg-1 pancuronium. Maintenance was obtained with a continuous infusion of 0.22 +/- 0.1 mg.kg-1.h-1 midazolam, 66% nitrous oxide in oxygen, and fentanyl (1.6 +/- 0.5 micrograms.kg-1.h-1). Nitrous oxide and midazolam were respectively stopped 10 and 1 min before giving the antagonist (5 micrograms.kg-1 flumazenil) if required (17 out of the 20 patients). Eye opening occurred a mean 42 +/- 32 s after giving the antagonist. At this time, there was a significant increase in mean arterial blood pressure (+ 11 mmHg) and heart rate (+ 7 b.min-1). Thiopentone, 66% nitrous oxide in oxygen and 0.5% halothane were given to re-induce and maintain anaesthesia for completion of the procedure. The day following surgery, 19 patients were unable to remember the period of intraoperative awakening. One patient, although remembering the episode, did not experience any pain or any other disagreement in relation to it. Two patients were given a second dose of flumazenil at extubation so as to improve the quality of their recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Principles of the measurement of energy expenditure].

Numerous methods can be used to assess energy expenditure (EE). The Fick method allows an easy calculation of EE in critically ill patients with Swan-Ganz catheters. Indirect calorimetry can be performed using either closed circuit or open circuit techniques. The latter is accurate when the patient is breathing air or low-FiO2 gaz mixture, but inaccurate at high FiO2. The accuracy of instruments, the presence of a leak-free system and the mathematical manipulations are critical points. Calorimetric studies performed in patients receiving high FiO2 must be interpreted with caution.

Calorimetry↗
PubMed1989

[Ventilatory strategies in the multiple-injured patient].

The main goal of mechanical ventilation in trauma patients is to optimize tissue oxygen delivery. Specific technics are used when indicated, i.e. curarization in shocked patients, hyperventilation in head injured patients with intracranial hypertension, independent lung ventilation in asymmetric lung injury or in bronchopleural fistula, and high frequency ventilation in bronchopleural fistula.

Brain Injuries↗
PubMed1989

Adverse effects of high dose carnitine supplementation of total parenteral nutrition on protein and fat oxidation in the critically ill.

The aim of the present study was to investigate the effects of continuous and acute L-carnitine supplementation of total parenteral nutrition (TPN) on protein and fat oxidation in severe catabolism. A critically ill and severely malnourished male patient received TPN (non protein energy = 41 kcal/kg/day, provided equally as fat and glucose) over 38 days, without L-carnitine for 23 days and with carnitine supplements (15 mg/kg/day) for the following 15 days. Subsequently, he was given carnitine-free enteral nutrition for 60 more days. A four-hour infusion of 100 mg L-carnitine was given on day 11 of each TPN period. Indirect calorimetry was carried out after 11 days of either carnitine-free or supplemented TPN and at the initiation of enteral nutrition. Additional measurements were performed 4 hours and 24 hours after the acute infusions of carnitine. The rate of protein oxidation and the respiratory quotient were found to be higher, and the rate of fat oxidation to be lower, with carnitine-supplemented TPN, than with either carnitine-free TPN or enteral nutrition. Acute infusion of carnitine resulted in an increased rate of protein oxidation and a reduced rate of fat oxidation on both TPN-regimens. These unfavourable effects on protein metabolism may be due to an impairment of fat oxidation by excess amounts of carnitine.

Journal Article↗
PubMed1989

Clinical relevance of L-carnitine-supplemented total parenteral nutrition in postoperative trauma. Metabolic effects of continuous or acute carnitine administration with special reference to fat oxidation and nitrogen utilization.

Carnitine-free total parenteral nutrition (TPN) is claimed to result in a carnitine deficiency with subsequent impairment of fat oxidation. The present study was designed to evaluate the possible benefit of carnitine supplementation on postoperative fat and nitrogen utilization. Sixteen patients undergoing total esophagectomy were evenly randomized and received TPN without or with L-carnitine supplementation (74 mumol.kg-1.d-1) during 11 postoperative days. On day 11, a 4-h infusion of L-carnitine (125 mumol/kg) was performed in both groups. The effect of supplementation was evaluated by indirect calorimetry, N balance, and repeated measurements of plasma lipids and ketone bodies. Irrespective of continuous or acute supplementation, respiratory quotient and fat oxidation were similarly maintained throughout the study in both groups whereas N balance appeared to be more favorable without carnitine. We conclude that carnitine-supplemented TPN does not improve fat oxidation or promote N utilization in the postoperative phase.

Adult↗
PubMed1988

[Effect of L-carnitine supplemented total parenteral nutrition on postoperative lipid and nitrogen utilization].

During episodes of trauma carnitine-free total parenteral nutrition (TPN) may result in a reduction of the total body carnitine pool, leading to a diminished rate of fat oxidation. Sixteen patients undergoing esophagectomy were equally and randomly divided and received isonitrogenous (0.2 gN/kg.day) and isocaloric (35 kcal/kg.day TPN over 11 days without and with L-carnitine supplementation (12 mg/kg.day). Compared with healthy controls, the total body carnitine pool was significantly reduced in both groups prior to the operation. Without supplementation carnitine concentrations were maintained, while daily provision of carnitine resulted in an elevation of total carnitine mainly due to an increase of the free fraction. Without supplementation the cumulative urinary carnitine losses were 11.5 +/- 6.3 mmol corresponding to 15.5% +/- 8.5% of the estimated total body carnitine pool. Patients receiving carnitine revealed a positive carnitine balance in the immediate postoperative phase, 11.1% +/- 19.0% of the infused carnitine being retained. After 11 days of treatment comparable values for respiratory quotient, plasma triglycerides, free fatty acids, ketone bodies, and cumulative nitrogen balance were observed. It is concluded that in the patient population studied here carnitine supplementation during postoperative TPN did not improve fat oxidation or nitrogen balance.

Adult↗
PubMed1988

Hemofiltration clearance of flecainide in a patient with acute renal failure.

Flecainide, a new antiarrhythmic drug, has been shown not no be removed to a significant extent by hemodialysis or peritoneal dialysis, in spite of a high renal clearance. Its systemic and hemofiltrate clearances, measured in a patient under continuous hemofiltration, were 402 and 19.7 ml/min respectively. The clearance ratio of less than 5% makes the contribution of hemofiltration to the elimination of flecainide clinically negligible.

Acute Kidney Injury↗
PubMed1988

Intravenous infusion of a medium-chain triglyceride-enriched lipid emulsion.

There has been much interest in the parenteral use of medium-chain triglycerides (MCT) as a noncarbohydrate energy source. This study examines the effects of infusion iv into postabsorptive normal subjects with three doses (0.5, 1.0, 1.5 g/kg.15 h) of an emulsion containing 56% MCT and 44% long-chain triglyceride (LCT) and comparing its metabolic effect with infusions of normal saline (NS) and an emulsion containing LCT alone. There were significant increases in serum beta-hydroxybutyrate and acetoacetate 5 and 15 h after the start of the MCT-LCT infusions. Increases were seen only after 15 h of NS, while none was observed during LCT alone. Triglycerides were increased in a dose-related fashion with MCT-LCT and were increased even further with LCT alone. Glycerol increased in a dose-related fashion both during the MCT-LCT and LCT infusion beginning immediately (0.5 h) after the start of the infusion. With NS infusion, glycerol increased significantly only after 15 h of infusion. The MCT-LCT mixture and the highest LCT dose resulted in a significant (12%) increase in oxygen consumption after 5 h of infusion. There was no difference in oral glucose tolerance between the various infusions. Infusion of MCT results in significant ketogenesis and more study is needed to determine its clinical utility.

Acetoacetates↗
PubMed1988

Changes in CSF pressure after mannitol in patients with and without elevated CSF pressure.

In view of the current concern that rapid infusion of mannitol might initially aggravate intracranial hypertension, the effects of a mannitol infusion on lumbar cerebrospinal fluid pressure (CSFP) were investigated in 49 patients. The studies were performed when the patients were under general anesthesia prior to elective craniotomy for tumor resection or intracerebral aneurysm clipping. The patients were divided into two groups: 24 patients with normal CSFP (Group I, mean CSFP 10.5 mm Hg) and 25 with raised CSFP (Group II, mean CSFP 20.8 mm Hg). Measurements of CSFP, mean arterial blood pressure (MABP), and central venous pressure (CVP) were made serially during and after the infusion of 20% mannitol (1 gm.kg-1 infused over a 10-minute interval). In both groups, mannitol infusion provoked a fall in MABP and an increase in CVP. An immediate decrease [corrected] in CSFP was observed in Group II, whereas CSFP increased transiently but significantly in Group I. Analysis of the arterial and venous driving pressures which contribute to CSFP suggests that the transient increase in CSFP after mannitol in Group I was partly due to the increase in CVP. The presence of intracranial hypertension may thus alter the CSFP response to arterial and venous pressure changes. Cerebral blood volume (CBV) was measured in dogs in a separate study analogous to the human protocol. The CBV increased approximately 25% over control values after mannitol infusion both in the normal animals and in those with CSFP raised by an epidural balloon. The response of the CSFP to mannitol infusion differed between both groups in a fashion similar to that observed in the human subjects. Thus, differences in CBV changes after mannitol do not account for the difference in CSFP response between normal subjects and those with raised CSFP.

Animals↗
PubMed1987

Accelerated idioventricular rhythm during flexible fiberoptic bronchoscopy.

We report the case of a patient who developed severe hypoxemia and an unusual arrhythmia, accelerated idioventricular rhythm, during flexible fiberoptic bronchoscopy. Coronary artery disease was subsequently suspected despite an unremarkable history and physical examination, and confirmed by a thallium 201 imaging. The appearance of accelerated idioventricular rhythm during fiberoptic bronchoscopy should raise the possibility of underlying coronary artery disease.

Aged↗
PubMed1987

Myocardial injury after electrical burns: short and long term study.

Miscellaneous cardiac abnormalities can occur after electrical burns. The long term outcomes are still unknown. We studied 10 patients, 9 of whom suffered high-voltage electrocution, and one of whom was struck by lightning. Serial electrocardiograms (ECG) and serum MB creatine phosphokinase isoenzyme (MB-CPK) activities were obtained during their stay in hospital. ECG and thallium 201 cardiac scintigraphy at rest, as well as echocardiograms were obtained in all patients 4 to 48 months after discharge. In hospital, 9 patients showed one or more abnormal findings at physical examination (4 cases), ECG (8 cases), MB-CPK (1 case). At long term follow-up, 5 patients had one or more myocardial functions or conduction abnormalities, with or without symptoms. One patient had compensated heart failure. Nine patients were asymptomatic. Abnormal ECG findings persisted in 3 patients. Three cardiac scans showed evidence of regional myocardial hypoperfusion. Decreases in left ventricular indices measured by echocardiogram were found in 3 patients. We conclude that high-voltage electrocution is associated with a high incidence of cardiac abnormalities, which may persist. Long term evaluation, requiring cardiac T1 201 scintigraphy and echocardiogram, may be justified.

Adult↗
PubMed1986

Effects of cholinergic stimulation and antagonism on plasma insulin concentration in lean and obese human subjects.

The effect of cholinomimetic stimulation by infusion of edrophonium chloride or muscarinic blockade by infusion of atropine sulfate on insulin and GIP secretion was studied in normal lean subjects during eu- and hyperglycemia. Cholinomimetic stimulation led to a slight non-significant increase and muscarinic blockade to a slight, non-significant suppression of both GIP and insulin. No modification of the insulin secretion pattern was observed under either condition during hyperglycemia. The effect of atropine infusion on fasting plasma insulin and GIP was subsequently studied in 11 obese patients and 10 lean subjects. Muscarinic antagonism by atropine led to a transient non-significant suppression of GIP and insulin in lean subjects, but to a significant, sustained suppression of these hormones in obese patients. Insulin and GIP levels were however, not suppressed to control values after atropine administration in obese patients. A positive correlation was found between fasting plasma insulin and maximal suppression of insulin attained during the 30 min following administration of atropine. It is concluded that part of the hyperinsulinemia observed in human obesity is under the control of the parasympathetic nervous system. An abnormal balance between sympathetic inhibitory and parasympathetic stimulatory tones on insulin secretion, as observed in the VMH lesioned rat, might be present in human obesity.

Adult↗
PubMed1986

Comparison of thermogenic effect of fructose and glucose in normal humans.

After nutrient ingestion there is an increase in energy expenditure that has been referred to as dietary-induced thermogenesis. In the present study we have employed indirect calorimetry to compare the increment in energy expenditure after the ingestion of 75 g of glucose or fructose in 17 healthy volunteers. During the 4 h after glucose ingestion the plasma insulin concentration increased by 33 +/- 4 microU/ml and this was associated with a significant increase in carbohydrate oxidation and decrement in lipid oxidation. Energy expenditure increased by 0.08 +/- 0.01 kcal/min. When fructose was ingested, the plasma insulin concentration increased by only 8 +/- 2 microU/ml vs. glucose. Nonetheless, the increments in carbohydrate oxidation and decrement in lipid oxidation were significantly greater than with glucose. The increment in energy expenditure was also greater with fructose. When the mean increment in plasma insulin concentration after fructose was reproduced using the insulin clamp technique, the increase in carbohydrate oxidation and decrement in lipid oxidation were markedly reduced compared with the fructose-ingestion study; energy expenditure failed to increase above basal levels. To examine the role of the adrenergic nervous system in fructose-induced thermogenesis, fructose ingestion was also performed during beta-adrenergic blockade with propranolol. The increase in energy expenditure during fructose plus propranolol was lower than with fructose ingestion alone. These results indicate that the stimulation of thermogenesis after carbohydrate ingestion is related to an augmentation of cellular metabolism and is not dependent on an increase in the plasma insulin concentration per se.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗