Epidemiology of hepatitis C in homosexual men.
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Adult↗
Biomedical subjects
K Lenz
Publications and source records attributed to K Lenz.
[Weaning using continuous-flow CPAP: hemodynamics and gas exchange].
The present study was designed to investigate hemodynamics and gas exchange during weaning from mechanical ventilation (assist/control mode) to spontaneous breathing with continuous high flow (chf)-CPAP, and to study the predictive value of these parameters in respect of longterm success or failure of weaning. Hemodynamic and gas exchange parameters were obtained in 10 patients without severe pulmonary and cerebral dysfunction at -240, -60, -30, and -15 min before, and at +15, +30, +45, +60, +120, +180, +240 min after chf-CPAP. During chf-CPAP significant increases in heart rate/min (92 +/- 17 to 103 +/- 20), cardiac index (3.9 +/- 0.7 to 4.4 +/- 1.0 1/min.m2), respiratory rate/min (15 +/- 1 to 28 +/- 7), PaCO2 (36.7 +/- 3.0 to 41.2 +/- 5.9 torr) and oxygen delivery (12.2 +/- 2.7 to 13.9 +/- 2.3 ml/min.kg) were found. Arterial and pulmonary artery pressures rose only briefly within the first hour. All other parameters changed non-significantly. In the 4 patients who required mechanical ventilation 12 to 34 hours after the end of the study we found a significantly more pronounced increase in heart rate than in those who where weaned successfully (114 +/- 19 vs 89 +/- 9). Increases in heart rate, respiratory rate, cardiac index, PaCO2 and oxygen delivery can therefore be expected during weaning from mechanical ventilation to spontaneous breathing with CPAP. A pronounced increase in heart rate may suggest a weaning failure.
Adult↗
Rapid transition from methadone maintenance to naltrexone.
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Flumazenil↗
Energy metabolism in patients with acute and chronic liver disease.
Energy expenditure and substrate oxidation rate for fat, glucose and protein were evaluated by indirect calorimetry in 20 normal individuals, 35 patients with acute hepatitis and 22 patients with biopsy-proven alcoholic cirrhosis in the postabsorptive state. Measurements were done in the resting state after an overnight fast (10 to 12 hr). Oxygen consumption (ml/min/1.73 m2) in normal subjects, in patients with acute hepatitis and in patients with cirrhosis was 206.5 +/- 4.0 (mean +/- S.E.M.), 216.4 +/- 4.7 and 228.8 +/- 7.1 (p less than 0.05 vs. controls), respectively. When related to body surface area (kcal/min/1.73 m2), resting energy expenditure did not differ between normal subjects (0.98 +/- 0.02), patients with acute hepatitis (1.03 +/- 0.02) and cirrhotic patients (1.06 +/- 0.03). However, when related to 24-hr urinary creatinine excretion as an estimate of lean body mass, energy expenditure was increased in cirrhosis (p less than 0.0001). In cirrhosis an inverse association between the severity of liver disease according to Pugh and oxygen consumption and resting energy expenditure was found. In cirrhotic patients the percentages of total calories derived from fat (86% +/- 5%), carbohydrate (2% +/- 4%) and protein (12% +/- 1%) were different from those of normal controls who metabolized 45% +/- 4%, 38% +/- 4%, 17% +/- 1%, respectively. In acute hepatitis no alterations in metabolism could be found apart from a decreased protein oxidation rate. In conclusion no appreciable changes in energy metabolism exist in acute hepatitis. The pattern of fuel use in cirrhosis resembles that in starvation.(ABSTRACT TRUNCATED AT 250 WORDS)
Acute Disease↗
Energy metabolism in acute and chronic renal failure.
Energy metabolism was measured by indirect calorimetry in 86 patients with various forms of renal failure and in 24 control subjects. In patients with acute renal failure with sepsis, oxygen consumption, carbon dioxide production, and resting energy expenditure were increased (P less than 0.05). In other groups with renal failure (acute renal failure without sepsis, chronic renal failure with conservative treatment or hemodialysis, and severe untreated azotemia) these indices were not different from those of control subjects. Urea nitrogen appearance was decreased in patients with chronic renal failure undergoing conservative treatment, in those with severe untreated azotemia, and in hemodialysis patients (P less than 0.05). We conclude that renal failure has no influence on energy expenditure as long as septicemia is absent. Reduced urea nitrogen appearance rates in chronic renal failure are due to a reduced energy and protein intake. Wasting is a consequence of decreased food intake but not of hypermetabolism in chronic renal failure.
Acute Kidney Injury↗
Acute blocking of naloxone-precipitated opiate withdrawal symptoms by methohexitone.
In a double-blind placebo-controlled trial of 18 patients, methohexitone blocked objective signs of opiate withdrawal caused by a bolus injection of naloxone. Furthermore, in continuing the naloxone therapy for 48 hours, no withdrawal signs appeared. Levels of withdrawal distress returned to normal levels within six days. This approach can be regarded as an effective and well tolerated withdrawal therapy with low drop-out rates.
Adult↗
Dopamine infusion in patients with hepatic encephalopathy: plasma levels and haemodynamic changes.
During a constant infusion of dopamine (DA 4.5 micrograms/kg/min), the plasma levels of DA reached at 30 min of infusion were 81 +/- 6.9 ng/ml and 71.6 +/- 14.8 ng/ml in patients with hepatic encephalopathy (HE) and control patients, respectively. In both groups of patients, the plasma levels of DA did not change between 30 and 60 min of continuous DA infusion. The DA infusion was associated with an increase of arterial blood pressure, heart rate and cardiac index. In the patients with HE, the increase in cardiac index was directly correlated with the plasma level of DA (r = 0.843, p less than 0.01). The present results clearly demonstrate that in HE circulating DA does not accumulate during continuous infusion of DA. They further provide evidence that the increase in circulating catecholamines in HE reflects increased release from the sympatho-adrenal system.
Adult↗
["Induced detoxification treatment" of opiate dependent patients--a new therapy concept].
Induced detoxification treatment of opiate addicts by means of naloxone was developed at the intensive care unit of the Department of Psychiatry at the University of Vienna. Two methods were tested 1. Rapid opiate withdrawal by means of a staggered naloxone regimen. 2. Ultrashort opiate detoxification during general anaesthesia using high doses of naloxone. In an open trial 15 patients were treated with staggered doses of naloxone while under tiapride. The various discomforts were satisfactorily reduced, and the detoxification syndrome was limited to 50 hours. In a second open trial 6 patients were administered 10 mg naloxone under general anaesthesia. All naloxone induced withdrawal syndromes can be suppressed by barbiturate anaesthesia. They do not appear even after the effect of the anaesthesia wears off if the patient is kept on a naloxone regimen as long as opiates remain present in the circulatory system. Both methods shorten detoxification treatment and provide smooth transition to a naltrexone maintenance programme.
Adult↗
Prevention of upper gastrointestinal bleeding in long-term ventilated patients. Sucralfate versus ranitidine.
Thirty-two long-term ventilated patients were randomly selected for a study of the efficacy of sucralfate (1 g six times per day via gastric tube) versus ranitidine (six 50-mg to six 100-mg doses per day intravenously) for the prevention of upper gastrointestinal bleeding. The patients of the two treatment groups (each 16) were comparable with respect to diseases precipitating acute respiratory failure and risk factors of bleeding, e.g., renal failure, thrombopenia, coagulopathy, and anticoagulant treatment. Mean duration of mechanical ventilation was 7.4 in sucralfate- and 7.7 days in ranitidine-treated patients. During mechanical ventilation, macroscopically visible bleeding developed in three of the sucralfate-treated (18.7 percent) and seven of the ranitidine-treated (43.7 percent) patients. Until the end of the study, only three of the sucralfate-treated but nine of the ranitidine-treated (56.2 percent) patients bled; the difference between the two treatment groups was at all times significant (p less than 0.05). Packed red blood cells had to be administered to the three bleeding patients in the sucralfate group and to seven bleeding in the ranitidine group. Therefore it seems that sucralfate prevented mostly minor bleeding. The high bleeding rate during ranitidine treatment was presumably due to the high number of pH-nonresponders, as almost 30 percent of the gastric aspirates of this group had a pH less than 5. During treatment no difference was found in positive blood culture specimens and bronchial secretions between the two groups. However, nosocomial pneumonia developed in two ranitidine-treated patients, whereas that complication developed in none of the sucralfate-treated patients. In long-term ventilated patients, sucralfate prevented minor upper gastrointestinal bleeding significantly better than ranitidine. However, this does not imply that major upper gastrointestinal bleeding can be prevented by either sucralfate or ranitidine in these patients.
Adolescent↗
Continuous naloxone administration suppresses opiate withdrawal symptoms in human opiate addicts during detoxification treatment.
In a small clinical trial, a new therapeutic approach was studied, whether naloxone, in high dosage over a prolonged period of time, will attenuate withdrawal symptoms in acute opiate detoxification. Six opiate addicts, satisfying DSM III-R criteria of opiate dependence, were given 10 mg naloxone under short barbiturate anaesthesia, followed by repeated doses of 0.4 mg/h naloxone for at least 72 h. Acute onset of withdrawal symptoms brought about a high dose of naloxone could be suppressed by the short barbiturate anaesthetic; neither continuous supply nor cessation of the naloxone regimen after 96 h caused any severe withdrawal symptoms. Morphine and naloxone measurements in blood at the start of naloxone therapy enabled pharmacokinetic explanations for this paradoxical action of naloxone to be excluded.
Adult↗
Assessment of oxygen-consumption by use of reverse Fick-principle and indirect calorimetry in critically ill patients.
Oxygen consumption was measured simultaneously by the reverse Fick-principle (V02FICK) and by indirect calorimetry ("Metabolic Measurement Cart Horizon") (V02MMC) in 31 critically ill patients; 24 men and 7 women. Seventeen patients were breathing spontaneously, 14 patients were on mechanical ventilation. The fractional inspiratory oxygen concentration (FI02) in ventilated patients ranged from 0.21 to 0.4 (mean 0.302). Total oxygen consumption as measured by indirect calorimetry was 286.7 +/- 59.7 ml/min (mean +/- SD), and measured by reverse Fick-principle 258.9 +/- 52.2 ml/min (mean +/- SD). The coefficient of correlation between the two methods was r = 0.873. The absolute difference of oxygen consumption between reverse Fick-method and indirect calorimetry was 11.3%. Regression analysis according to Theil revealed a similar regression between spontaneously breathing and mechanically ventilated patients for the studied FI02 values below 0.4. It is concluded that indirect calorimetry is a reliable method for measuring oxygen consumption in spontaneously breathing as well as mechanically ventilated critically ill patients.
Journal Article↗
Beneficial effect of 8-ornithin vasopressin on renal dysfunction in decompensated cirrhosis.
In nine patients with decompensated alcoholic cirrhosis of the liver and impaired renal function the effect of 8-ornithin vasopressin (ornipressin) on renal function and haemodynamic parameters was studied. Ornipressin was infused at a dose of 6 IU/h over a period of four hours. During ornipressin infusion an improvement of renal function was achieved as indicated by an increase of creatinine clearance (76 (15)%; p less than 0.01), urine volume (108 (29)%; p less than 0.05) and sodium excretion (168 (30)%; p less than 0.05). The hyperdynamic circulation of hepatic failure, as characterised by increased cardiac index and heart rate as well as decreased systemic vascular resistance was reversed to a nearly normal circulatory state during ornipressin infusion. The raised noradrenaline plasma concentration (1.74 (0.31) ng/ml) and plasma renin activity (13.5 (3.9) ng/ml/h) were lowered during ornipressin infusion to 0.87 (0.21) ng/ml and 5.9 (2.1) ng/ml/h, respectively (p less than 0.01). The efficacy of a vasoconstrictor agent in reverting a hyperdynamic state and improving renal function provides evidence for the substantial role of accumulation of vasodilator substances and subsequent activation of sympathetic nervous system and renin-angiotensin-axis in the pathogenesis of renal dysfunction in hepatic failure. Values are expressed as mean (SE).
Female↗
Opiate detoxification under general anesthesia by large doses of naloxone.
For opiate detoxification 6 volunteer opiate addicts were intravenously administered 10 mg naloxone within one hour while under barbiturate anesthesia. During administration of naloxone none of the patients demonstrated significant changes in the hemodynamic parameters of heart rate, mean arterial pressure, cardiac index, peripheral resistance or in the oxygen saturation. After patients awoke from anesthesia, they experienced no or only minimal withdrawal symptoms. Possible explanations for the suppression of withdrawal symptoms are discussed.
Adult↗
Phenylalanine and tyrosine metabolism in renal failure: dipeptides as tyrosine source.
Several lines of evidence suggest that tyrosine formation is impaired in renal failure. The concentration of tyrosine is decreased and the phenylalanine/tyrosine ratio is increased in plasma and in skeletal muscle cells. After an oral or intravenous load, the rise of plasma phenylalanine is augmented, the clearance is decreased, oxidation is diminished and the corresponding rise of plasma tyrosine level is blunted. Tyrosine elimination and oxidation are not altered in uremia. The defect in tyrosine formation may be especially important in uremic patients on a low protein diet supplemented with tyrosine-free essential amino acid preparations and in subjects on artificial nutritional support. Thus, tyrosine should be regarded as a conditionally essential amino acid in renal failure and should be supplied exogenously, at least in these patient groups. Oral tyrosine supplementation was shown to replete plasma and intracellular pools and improve nitrogen balance in chronic renal failure patients on a low protein diet. However, because of poor solubility in aqueous solutions, tyrosine cannot be included in the free form in amino acid solutions for parenteral nutrition. To circumvent stability or solubility problems, tyrosine containing dipeptides and/or N-acetyl-tyrosine may serve as tyrosine sources for parenteral supply. Renal failure does not affect alanyl-tyrosine hydrolysis, and there is an immediate increase of plasma tyrosine concentration after peptide infusion. Elimination and hydrolysis of glycine-tyrosine is retarded in renal failure, but the clearance exceeds clinically relevant infusion rates. After infusion of N-acetyl-tyrosine, no increase in plasma tyrosine is seen, and the half-life N-acetyl-tyrosine is grossly prolonged in uremia.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Improvement of hepatic encephalopathy treated with flumazenil.
The effects of the benzodiazepine antagonist flumazenil were studied in 20 episodes of hepatic encephalopathy (HE) in 17 patients with acute (n = 9) or chronic (n = 8) liver failure who had not responded to conventional therapy. Patients with a history of benzodiazepine intake were excluded. Changes in HE stage, in Glasgow coma scale, and in somatosensory evoked potentials were measured. In 12 of 20 episodes HE stage improved. The response to treatment occurred rapidly (within 3-60 min). In 8 of these 12 episodes HE worsened 0.5-4 h after treatment. In 5 of the 8 episodes that did not respond to flumazenil patients had clinical evidence of brain oedema. Flumazenil may be valuable in the treatment of HE in acute and chronic liver failure.
Acute Disease↗
Influence of fluid replacement on extravascular lung water (EVLW) in patients with diabetic ketoacidosis.
Fluid replacement is a major issue in the treatment of patients with diabetic ketoacidosis. During this therapy, development of pulmonary edema has been reported and attributed to an increase in pulmonary microvascular pressure and a decrease in colloid-osmotic pressure (COP). Because clinically apparent pulmonary edema is associated with an increase in extravascular lung water (EVLW) and impairment of pulmonary gas exchange, we studied the effect of fluid replacement on EVLW, COP, pulmonary hemodynamics and gas exchange parameters in 8 patients with diabetic ketoacidosis (blood glucose greater than 300 mg/dl, pH less than 7.1). EVLW was estimated by the thermal-dye technique. All variables were successively determined upon admission (A), after initial fluid replacement (IFR), when glucose had fallen below 180 mg/dl, after 8 h of intravenous glucose treatment (G), and after 24 h of total parenteral nutrition (TPN). Despite a total net fluid intake of 6.0 +/- 1.61, a significant decrease (p less than 0.001) in COP from 29.6 +/- 5.5 at A to 18.8 +/- 2.2 mmHg after TPE and a significant increase (p less than 0.001) in PCWP from 4 +/- 2 at A to 10 +/- 3 mmHg after TPE, EVLW remained almost unchanged. EVLW was 5.1 +/- 2.8 at A, 5.3 +/- 2.1 after IFR, 4.8 +/- 1.4 after G, and 5.3 +/- 1.7 ml/kg after TPN. However, PaO2 decreased from 137 +/- 17 at A to 87 +/- 10 mmHg after TPE (p less than 0.001), while Qs/Qt increased significantly (p less than 0.05). The alterations in gas exchange may be indicative of pulmonary dysfunction but as they were not associated with accumulation of EVLW, they may as well reflect the compensation of metabolic derangements in diabetic ketoacidosis.
Adult↗
Naloxone treatment for opiate withdrawal syndrome.
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Humans↗
Effect of flumazenil in hepatic encephalopathy.
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Adult↗