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Biomedical subjects

J Eckart

Publications and source records attributed to J Eckart.

At least 19 recordsLinked to original sources
PubMed1995

Time constant/volume relationship of passive expiration in mechanically ventilated ARDS patients.

Since the adult respiratory distress syndrome (ARDS) lung is known to be inhomogeneous, one could expect an uneven distribution of expiratory time constant during uninterrupted mechanical ventilation. We investigated the time constant/volume relationship of passive expiration, and their modification by external resistive elements. In 12 paralysed intubated ARDS patients, we determined the expiratory time constant (tau E) as a function of the expired volume (VE) during uninterrupted mechanical ventilation. Mean expiratory time was 2.9 +/- 0.3 s (+/- SD). VE was divided into five equal volume slices (portions) and a mean tau E calculated from the expiratory tidal volume/flow curve for each slice. The mean values of tau E for each volume slice did not differ significantly throughout expiration, averaging 690 +/- 218 ms (mean +/- SD of five slices and 12 patients). We show that the flow-dependent resistance of the endotracheal tube (RETT) is mainly responsible for the observed time constant homogeneity. We conclude that in ARDS patients during uninterrupted mechanical ventilation the time constants of passive expiration are markedly modified by the flow-dependent resistance of the endotracheal tube (RETT), and also by the external resistance of tubing and ventilator (REX). RETT and REX render tau E about three times larger than the time constant of the patient's respiratory system alone.

Adult↗
PubMed1993

[Can administration of trasylol in reduced Hammersmith dosage with simultaneous transfusion of autologous blood meet the requirements of open heart surgery?].

PROBLEM: The general positive effect of the proteinase inhibitor trasylol on blood loss and transfusion demand in cardiac surgery has been demonstrated in several placebo-controlled studies. Given the possibility of cardiac and renal side effects associated with a high dose of trasylol (Hammersmith dosage: 6 x 10(6) kallikrein inactivator units KIU), the question of a dose reduction was raised. METHODS: Being designed as a randomized double-blind comparative group study, the investigation included 120 patients with elective primary cardiac surgery from November 1990 to April 1992. One characteristic aspect of this study was the combined administration of trasylol and autologous blood transfusions. To compare the efficacy and safety of different doses of trasylol, two groups, each with 60 patients, were created: the former with the full Hammersmith dose (high dose group = HD group), the latter with half of the Hammersmith dose (los dose group = LD group). A placebo group had to be excluded for ethical reasons. RESULTS: The trasylol plasma levels showed a good dose correlation for the complete interval. The intra-operative bleeding tendency, as judged by the surgeons in charge, did not show any statistical significant difference between the HD group and the LD group. As to the post-operative blood loss via thoracic drainage, the early collection periods did not show any difference between both study groups. Starting at 6 hours post-operatively, the drainage losses showed a tendency towards lower volumes in the HD group. This difference was statistically significant for the time period "6-12 hours post-operatively". The analysis of the post-operative complications did not show any difference. SUMMARY: In this study with a high percentage of autologous blood transfusions, a lower dose of trasylol seemed to be nearly as effective as a full Hammersmith dose. However, such a reduced dose did not demonstrate any advantage regarding the complication rate in comparison with the conventional high dose.

Aprotinin↗
PubMed1992

[Initial experiences with rigid angled optical systems as intubation aids in difficult intubation].

Referring to a classification by Cormack, difficult laryngoscopy of Grade 3 (only the epiglottis or a part of it can be seen) was simulated in 16 patients by lowering the blade of the laryngoscope, so that the epiglottis was pushed down and thus covered up the vocal cords. The object of the study was to test whether a newly developed rigid endoscope is a useful tool during intubation in cases of laryngoscopical view Grade 3. After simulation of Grade 3 as mentioned above, using a clip, an angle optic was fixed to the vertical part of the blade, so that the movement of the optic in the sagittal level was still possible. If an improvement of the laryngoscopical view was possible, the tracheal tube was inserted via the nasal route until the top of the tube could be seen in the oropharynx. The tracheal tube was inserted into the trachea, under endoscopic control. With this new method, naso-tracheal intubation under endoscopic control in all 16 patients was successful, without affecting the pharynx and the vocal cords.

Endoscopes↗
PubMed1992

Intrinsic PEEP monitored in the ventilated ARDS patient with a mathematical method.

Under mechanical volume-controlled ventilation, the intensive care patient can develop intrinsic positive end-expiratory pressure (iPEEP); that is, the passive expiration is terminated by the following inspiration before the alveolar pressure comes to its physical equilibrium value. We present a mathematical method to estimate this alveolar dynamic iPEEP breath by breath, without the need of a maneuver. We tested it in paralyzed patients ventilated for adult respiratory distress syndrome after multiple trauma and/or sepsis, and we compared the results obtained with the new mathematical method with those from the occlusion method introduced by Pepe and Marini. The results agreed well (median difference of 0.8 mbar in 201 investigations in 12 patients). However, the mathematically determined values, representing dynamic iPEEP, are systematically slightly smaller than those measured by the occlusion maneuver. A variation of expiratory time suggests that this difference might be due to mechanical time-constant inhomogeneity, viscoelastic processes, or other mechanisms showing time dependence.

Adult↗
PubMed1990

[Energy requirements of surgically treated, injured and infected patients].

There is always a distinct increase in energy expenditure in postoperative, posttraumatic and septic patients. In order to predict this increase in energy expenditure an enormous number of formulas have been developed. However, the problem with all these formulas is that they cannot sufficiently take into account the peculiarities of the underlying disease, the general and nutritional condition or the varying influence of the phase of disease. Furthermore, all these patients continuously show a considerable change in body weight which can be attributed to a shifting of the water balance. In all of these cases any calculation of energy expenditure based on body weight will inevitably be incorrect. Therefore, it is recommended that predicting formulas only be used as orienting guidelines in all uncomplicated postoperative or posttraumatic courses. In patients with multiple injuries or septic complications the real energy expenditure should be measured by indirect calorimetry in order to adapt energy intake during enteral or parenteral nutrition to the very different metabolic situations.

Burns↗
PubMed1989

[Distribution and elimination of medium- and long-chain fatty acids of a fat emulsion in lipoproteins of severely injured patients following bolus injection].

A fat emulsion containing 20% fat as medium chain triglycerides (MCT) and long chain triglycerides (LCT) (1:1) was injected as a bolus in an amount of 0.2g fat per kg body weight to six patients, three to five days after a serious injury. Triglyceride concentrations increased within two min in lipoprotein fractions d less than 0.95 g/ml (Chylomicrons), d less than 1.006 g/ml (VLDL), d less than 1.063 g/ml (LDL) and d less than 1.21 g/ml (HDL). Sixty minutes after injection triglyceride concentrations had again reached preexperimental values in all lipoprotein fractions. Cholesterol values did not change. According to the composition of the fat emulsion, linoleic acid content increased in triglycerides of all lipoprotein fractions, whereas octanoic and decanoic acid did so only in triglyceride-rich lipoproteins (d less than 1.006). Half-life values of elimination of octanoic acid (3.3 min) and decanoic acid (3.9 min) in triglycerides of lipoprotein fraction d less than 1.006 were nearly half as short as that of long chain fatty acids (linoleic acid, 6.4 min; oleic acid, 6.5 min; palmitic acid, 7.5 min). Thus in contrast to LCT, MCT are only found in triglyceride-rich lipoproteins (d less than 1.006) and are also eliminated more rapidly.

Fat Emulsions, Intravenous↗
PubMed1989

Indications for combined high frequency ventilation in clinical use.

A retrospective study of 20 surgical intensive care unit patients is reported. They were ventilated with continuous positive pressure ventilation (CPPV) and then switched to combined high frequency ventilation (CHFV). To find why there were variable responses to CHFV, the data of 20 patients were retrospectively evaluated with respect to respiratory index (RI), compliance (C) and extravascular lung water (EVLW). The results suggest that the indication line for CHFV was a C value greater than 45 ml/cmH2O and an EVLW value greater than 15 ml/kg BW.

Adult↗
PubMed1989

[Side effects and complications of parenteral nutrition].

Despite increasing advances in total parenteral nutrition, a lot of partly serious side effects have been seen. This includes among other things the lactic acidosis after high amounts of carbohydrates or the deficiency and excessive expenditure respectively, of thiamine in carbohydrate metabolism. Metabolic changes in bone system, especially with long term parenteral nutrition are reported by american groups. Cholestasis is often caused by intravenous feeding. In patients with malnutrition a carefully balanced supply of calories and phosphate should be offered. Without misuse of TPN, the rate of complications is very low.

Acid-Base Equilibrium↗