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Biomedical subjects

W Heinrichs

Publications and source records attributed to W Heinrichs.

At least 55 records · Page 3Linked to original sources
PubMed1992

Physician and nursing (personnel) requirements for ICUs. Therapeutic Intervention Scoring System (TISS) versus time requirements for patient care--a comparative study in an interdisciplinary surgical intensive care unit.

OBJECTIVE: To measure total physician manoeuvres and total nursing manoeuvres in intensive care patients and to compare the results with calculated personnel requirements on the basis of TISS scores. DESIGN: Open prospective study. SETTING: Sixty-three ICU patients on two consecutive days. MEASUREMENT: 1. Total physician activities (TPM) in minutes/patient-day; total nursing manoeuvres (TNM) in min/patient-day. 2. TISS Calculation of personnel requirements on the basis of both parameters. RESULTS: TPM averaged at 3.9 hours. No fixed correlation was established between TISS and TPM. TNM averaged 1,073 minutes/patient-day and demonstrated a good correlation with TISS. CONCLUSIONS: Physician activities on a surgical ICU averaged 3.9 hours/patient-day. Nursing manoeuvres average 17.9 hours/patient-day. Individual measurements must be made before calculating personnel requirements on the basis of TISS scores.

Adolescent↗
PubMed1992

[Propofol for sedation during postoperative mechanical ventilation. A comparative study with Lytic Mixture].

Propofol infusion was found to provide excellent sedation and rapid recovery in intensive care. The present study compared Propofol with lytic solution (lytic solution = mixture of 100 mg Pethidine, 50 mg Promethazine and 0.6 mg Dihydroergotamine) during 6 hours of postoperative artificial ventilation. 60 patients after major abdominal surgical procedures were studied with ethical committee approval and informed consent. Patients were randomly allocated to receive either Propofol or lytic solution. We aimed at a sedation level of stage 5 according to the Ramsey score. The mean drug dosages were 3.9 mg/kg/h of Propofol and 4.2 ml/h of lytic solution. Hemodynamic values, blood gases as well as various biochemical measures did not show any difference between the groups. At the end of the sedation period triglyceride concentrations were significantly higher in patients receiving Propofol (166 + 79 mg/dl) compared to the control group (97 + 60 mg/dl). Significant and relevant differences were found for the times of recovery after discontinuation of the sedative. These times were very short in the Propofol group. Furthermore, in view of a longer recovery time after lytic solution in this group the respiratory rate was significantly slower up to the end of the observation period. We conclude that a major advantage of Propofol in the present study was the rapid recovery after 6 hour sedation. Patients gain vigilance rapidly and sufficient spontaneous respiration within minutes. Not at least thanks to these facts patient's safety can be improved in the recovery period.

Abdomen↗
PubMed1992

[Positive end-expiratory pressure (PEEP)].

PEEP has become a widely used ventilatory technique. The beneficial effects of PEEP were first described in asphyctic neonates, and it was later used in the treatment of cardiogenic pulmonary edema. Since the 1970s PEEP has been well established for the treatment of ARDS; the technique is also used for scoring the degree of severity of ARDS. Two mechanisms have been identified to explain pulmonary function and gas exchange following PEEP therapy: increasing FRC and alveolar recruitment. Both factors result in improvement in the ventilation/perfusion ratio with a consequent decrease in the intrapulmonary right-to-left shunt fraction. PEEP should be used in cardiogenic pulmonary edema as well as in ARDS; there are few contraindications. To choose the individual level of PEEP, PEEP should be titrated in 3- to 5-cm increments and its effects on haemodynamic function, pulmonary gas exchange and respiratory mechanics taken into account. In this article the effects of PEEP, its use and abuse are reviewed from a practical point of view.

Contraindications↗
PubMed1992

[Registration and analysis of airway pressure and gas flow in ventilated patients. The "Hyper-DAQ Respiration Mechanics Recorder"].

Respiratory data monitored in ventilated patients commonly consists of monitoring some inspiratory and expiratory pressures and volumes. For a more sophisticated analysis of respiratory mechanics in ventilated patients, a combined hardware and software system is presented that allows for continuous monitoring of airway pressure and gas flow. Gas flow is measured using a pneumotach. The "Hyper-DAQ" is an 8-channel 12-bit analog to a digital converter that can be connected to IBM PCs as well as to Macintosh computers using a standard RS 232 link. A special module consisting of three pressure transducers (airway pressure, differential pressure for a Fleisch head and ambient pressure) and five additional analog inputs is used for recording respiratory data. Once set up, the Hyper-DAQ records all the data in real time, independently of the host system that can query the data via the RS 232 link. The software runs on IBM and compatible PCs, as well as on Macintosh computers. The software simulates a strip-chart recorder and can be controlled by the keyboard and the mouse. We developed special software for the calibration of pressure and flow. Using models of the gas distribution in the lung compliance, resistance and lung time constants can be calculated from the raw data. For special purposes the data can be transferred to spread-sheet software. A mainstream CO2-detector connected to one of the additional analog inputs allows for additional data: alveolar ventilation, series deadspace, etc. The system presented can be recommended in routine work as well as for scientific studies in ventilated patients.

Anesthesiology↗
PubMed1990

[Maximal turnover rates of glycolysis enzymes and of the citrate cycle of separated granulocytes in the postoperative period].

The human granulocyte is easy to obtain and shows a nearly complete enzymatic equipment. It therefore represents an interesting model for in-vitro studies of metabolic disorders under various clinical conditions. In the presented study, the activities of several enzymes of glycolysis and citric cycle are measured in granulocytes separated from surgical patients (n = 10). Blood samples of 20 to 40 ml were drawn 6.5 +/- 4.8 hours after termination of surgical procedure. All patients were artificially respirated and nourished intravenously according to the results of indirect calorimetry. Hexokinase (HK), pyruvate kinase (PK), lactate dehydrogenase (LDH), and isocitrate dehydrogenase (IDH) were measured photometrically in the cell homogenate. The values were compared to those determined in a group of healthy, not-anesthetized persons, nourished and studied identically (n = 12). In granulocytes separated from patients following major surgery we found increased activities of HK (29.8 vs. 24.1 mU/mg protein in controls), LDH (2,484 vs. 1,868 mU/mg protein, p less than 0.01) and IDH (41.5 vs. 35 mU/mg protein, p less than 0.05), and a reduced activity of PK (1,623 vs. 2,265 mU/mg protein, p less than 0.01). Assuming that the alterations in enzyme activities of isolated granulocytes reflect metabolic alterations of the whole organism to a certain extent, the results can be interpreted as a decreased induction of PK by insulin, an increase of lactate recycling via Cori cycle (LDH), and a stimulated substrate flux in citric cycle (IDH). The separated human granulocyte is recommended as a model of posttraumatic metabolic disorders. It should be taken into consideration for studies leading to further improvement of nutrition during posttraumatic glucose mal-utilization.

Adult↗
PubMed1989

Accuracy of delivered versus preset minute ventilation of portable emergency ventilators.

The accuracy of delivered minute volume (VE) ventilation of portable emergency ventilators (PEV) was evaluated. Five PEV from three manufacturers were adapted to an artificial lung for varying compliance and resistance. Each PEV was tested in the "no airmix" (pure oxygen) and "airmix" (approximately 60% oxygen) setting at different frequencies and VE. Measurement of delivered VE (VEdel) was made using a pneumotachograph and digital integration of the flow values greater than 1 min (maximal error +/- 2%). Maximal inspiratory pressure (Pinsp) was measured with a transducer. Two PEV from one manufacturer produced severe hyperventilation when used at low VE (i.e., in children). Two other PEV from another manufacturer produced less marked hyperventilation, but revealed unexpected hypoventilation during conditions of higher inspiratory pressures (i.e., in adults with reduced compliance). The prototype PEV that was tested also revealed less marked hyperventilation with small decreases (down to -10% of the VE at higher Pinsp values). Further investigation is needed before this prototype goes into production. Manufacturers should redefine predicted values or machine settings or indicate that use of these devices may produce results which are not in accordance with the machine settings. Until adjustments are made, ventilation should be monitored when possible by measurement of end-tidal PCO2 or systemic arterial blood gases.

Adult↗
PubMed1989

[Procedure for calculating various parameters of the metabolism of amino acid mixtures].

For the evaluation of indirect calorimetry, elements are used, which specify the relation between nitrogen (N) excretion and amount of oxidized amino acids (AS/N) and between nitrogen excretion and oxygen-/carbon dioxide-exchange of the corresponding amounts of amino acids (O2/N, CO2/N). These elements are only valid for the amino acid mixture which was used for their determination, and only under the condition of complete combustion of deaminized amino acid skeletons. We developed a computer program, which is able to simulate complete oxidation, maximal gluconeogenesis, and maximal lipogenesis for a given amino acid mixture of any composition. The parameters AS/N, O2/N and CO2/N were calculated by the program for various parenteral amino acid solutions. Range of error was determined exemplarily for the use of standard parameters. The calculations demonstrate errors up to 50% for the calculation of substrate turnover in indirect calorimetry, depending on composition and actual metabolism of amino acid mixtures. As long as these influencing factors are not known in stress metabolism, we recommend to use those elements, which were calculated for the amino acid solution in use, assuming complete combustion.

Amino Acids↗
PubMed1989

[The effect of nifedipine and fentanyl on changes in the circulatory reaction to endotracheal intubation].

UNLABELLED: Recommendations for prevention of hypertension and tachycardia during the induction of anesthesia include the use of fentanyl and antihypertensive drugs and superficial anesthesia of the throat. Nifedipine has been used to treat acute hypertension and in many cases it has proved superior to other antihypertensive drugs. The present study was designed to find whether prophylactic injection of nifedipine alone or in combination with fentanyl can prevent cardiovascular responses during endotracheal intubation. METHODS: A total of 140 female patients (ASA groups I or II) with no history of arterial hypertension were randomly allocated to 7 groups: group K was the control group, in which patients received only saline solution; patients in groups 0,1F; 0,2F; 0,3F received 0.1, 0.2 or 0.3 mg fentanyl, respectively; those in group 1,0N, 1 mg nifedipine; those in group 0,5N + 0,1F, 0.5 mg nifedipine, plus 0.1 mg fentanyl; and those in group 1,0N + 0,1F 1 mg nifedipine plus 0.1 mg fentanyl. Blood pressure and heart rate were measured at 1 min intervals. After estimation of control values the prophylactic drug or combination of drugs was injected. Anesthesia was induced in the conventional manner. Plasma concentrations of epinephrine and norepinephrine were analyzed before intubation and at 5, 30 and 60 min intervals after intubation. Side-effects, especially respiratory depression and arrhythmia, were carefully recorded. RESULTS: In group K only systolic BP increased significantly after intubation. In the other groups the peak systolic blood pressure was not statistically different from the preinjection values. Diastolic BP increased significantly after intubation in all but two groups: in group 0,3F and in group 1,0N + 0,1F there was no significant difference in diastolic BP compared with the control values. The heart rate increased significantly in the control group after intubation as well as in groups 0,1F and 0,2F. In patients receiving 0.3 mg fentanyl there was no change in HR after intubation. Administration of 1 mg nifedipine alone (group 1,0N) or in combination with 0.1 mg fentanyl (group 1,0N + 0,1F) caused tachycardia even before intubation, whereas the combination of 0.5 mg nifedipine and 0.1 mg fentanyl did not result in a significant increase of HR following intubation. In all groups, epinephrine concentrations were significantly lower 5 min after intubation. A return to the control values was observed after 60 min in all groups except group 0,1F. Serum concentrations of norepinephrine were lower 5 min after intubation in all groups and were still low in groups 0,1F , 0,2F, 0,5N+0,1F and 1,0N+0,1F up to 60 min after intubation. Side-effects and adverse effects were checked for in the present study. An increase in heart rate was observed during induction in almost every group. More pronounced changes were recorded in groups 1,0N and 1,0N+ 0,1F receiving 1 mg nifedipine.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1989

[The Oxytron: a new device for administering oxygen in the spontaneously breathing patient].

The Oxytron (Weinmann, Hamburg, FRG) electronic oxygen conserver (patent pending) is a new device designed to deliver precise amounts of oxygen at the optimum point in the breathing cycle via a nasal cannula. In 200 Oxytron the delivered volume of oxygen was 35 +/- 5 ml within 150-200 ms at the beginning of the inspiratory phase of the respiratory cycle. Four different settings are possible: setting 1 provides one insufflation every 4th breath; setting 2 provides one insufflation every 2nd breath; setting 3 provides three insufflations every 4 breaths; and setting 4 provides an insufflation with every breath. These settings provide approx. The equivalent of 1-4 l oxygen per minute on a continuous flow basis. Both clinical experience and literature reports show variations in savings, with an average ratio of approx. 6:1 to 7:1. In the clinical evaluation, the following advantages were found: easy handling, exact oxygen delivery, increased oxygen saving and increased oxygen delivery with increasing respiratory rate. Due to the lack of any alarm system monitoring disconnection or failure of oxygen supply must be considered a disadvantage.

Anesthesia↗
PubMed1989

[Monitoring critically ill patients during transport by helicopter using a patient with abdomen apertum as an example].

Noninvasive continuous monitoring systems are newly emerging as an important means of monitoring during transports in emergency care, e.g. transportation by helicopter. While automatic oscillometric blood pressure monitors have been used in the perioperative area for some time, a similar development can be observed in the field of emergency care and transportation with the availability of light, portable and battery operated systems. For monitoring adequate oxygenation, pulse oximeters have recently been brought into discussion for both the perioperative period and the transport of critically ill patients. In contrast to well-established monitoring techniques during helicopter transports (ECG, inspection, manually measured blood pressure (BP), pulse oximetry reveals an oxygen deficiency due to respiratory and cardiocirculatory problems, enabling precious time to be saved. This concept is illustrated during the helicopter transport of a critically ill patient with abdomen apertum caused by Clostridium perfringens infection. Even with a critical look at the already described mishaps of this method--e.g. overestimation of true O2 saturation (sO2) and additional overestimation caused by Hb-derivatives--pulse oximetry was found to be superior to the established monitoring techniques. Furthermore, oscillometric blood pressure detection was very satisfactory during the 30-min helicopter transport. Based on our results, we believe pulse oximetry and automatic oscillometric BP-measurement to be useful for monitoring during transports in helicopters, thus improving patient safety.

Abdomen↗
PubMed1988

[Assessment of fluid content of the lung by thoracic radiography. Comparison of extravascular lung water measurement and results of radiological estimation methods].

Extravascular lung water (EVLW) was determined with the thermal-dye double-indicator method (119 individual measurements) in 23 patients in an intensive-care unit, and the results were compared with estimates made from largely standardized portable chest X-ray films, using the staging method of Sibbald as well as that of Halperin. There was a significant correlation with the measured EVLW for both methods. Radiologically "normal" films corresponded to a mean EVLW value of 8.4 ml/kg body-weight. Radiologically judged adjacent stages did not in all cases compare with corresponding measured EVLW values. But when EVLW values were clearly abnormal, the X-ray films always demonstrated massive interstitial or alveolar infiltrations. Measurement of EVLW enables one accurately to judge the fluid contents of the lung and is superior to the assessment of the chest X-ray film.

Adult↗
PubMed1988

[An on-line computer procedure for the analysis of pressure-volume relations in ventilated intensive care patients].

The inspiratory pressure-volume relationship (PV curve) describes elastic and viscous attributes of the respiratory system. The most frequently considered parameter is the quasi-static compliance, which has been used for evaluating optimal positive end-expiratory pressure (PEEP) in the treatment of patients with adult respiratory distress syndrome (ARDS). According to Falke and others, this method has not fulfilled its purpose. Since certain effects of PEEP ventilation such as the recruitment of lung areas on the one hand and the overdilatation of opened areas on the other may be reflected in different courses of parts of the PV curve, the consideration of discrete points on this curve may aid in developing mechanical criteria for the evaluation and control of artificial ventilation. Depending on lung elasticity, resistance, and tidal volume, the PV curve has a characteristic shape: initially it increases progressively until a certain airway pressure is reached, then it turns to a regressive incline. As irregularities of the PV curve due to oscillations of the respiratory gases cannot be avoided in practice, certain points (e.g. the inflection point) cannot be determined directly on the basis of the measured sample pairs. Therefore, we developed an on-line analysis of the PV curve, applying a polynomial function by least-square-fit procedure. The transthoracic pressure gradient was measured at the endotracheal tube by a Statham transducer. Inspiratory flow was measured using a Fleisch pneumotachograph with a differential pressure transducer. The flow-pressure signals were registered with a personal computer including an analog/digital interface board. Sample time was set for 10 ms.(ABSTRACT TRUNCATED AT 250 WORDS)

Critical Care↗
PubMed1988

[Changes in pulmonary hemodynamics, gas exchange and extravascular lung fluid in esophageal resection].

Postoperative convalescence after esophagectomy is frequently complicated by pulmonary insufficiency and a high mortality rate. The literature and our own observations suggest that pathological changes actually begin during the operative procedure; we therefore studied 11 male patients during and after esophageal surgery by monitoring heart rate, systemic and pulmonary arterial pressures, cardiac output, extravascular lung water (EVLW), cardiac index, and systemic (TPR) and pulmonary vascular resistance (PVR). Blood samples were taken for analysis of epinephrine, norepinephrine, serotonin, and arterial and mixed-venous blood gases. The changes were found to be most marked during esophageal resection: PaO2 decreased from 217 to 147 mmHg while PaCO2 increased, i.e. pulmonary gas exchange was disturbed (Fig. 4). PVR (Fig. 3) and mean pulmonary arterial pressure (MPAP) (Fig. 2) increased after esophagectomy. Norepinephrine, but not epinephrine (Fig. 6), increased continuously until the end of the operation. EVLW was slightly elevated at approximately 9 ml/kg body weight before operation and did not change during surgery. Six patients who developed severe pulmonary complications showed lung water retention up to 18 ml/kg body weight on the 4th postoperative day (Fig. 5). Compression of the heart and lungs as well as injury of the vagus nerve during esophagectomy may provoke increased MPAP, PVR, and disorders of pulmonary gas exchange. Furthermore, the non-respiratory function of the lung must be taken into consideration: the lung is known to have clearance activities for various endogenous substances such as norepinephrine, serotonin, some prostaglandins, and bradykinin. Most of these substances may provoke vasoconstriction followed by disturbances of microvascular permeability and gas exchange in the lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗