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Biomedical subjects

P Lotz

Publications and source records attributed to P Lotz.

At least 37 records · Page 2Linked to original sources
PubMed1982

[Delayed use of PEEP for respiratory resuscitation following standardized near-drowning with fresh and saltwater].

Investigations on the delayed use of PEEP following a standardized form of near drowning with 12.5 ml/kg body weight of either fresh or salt water were carried out on 14 anaesthetized and ventilated young pigs. After a 3 min period of apnoea the animals were ventilated with 100% oxygen and with either the same or an increased tidal volume, and a PEEP of 5 cm H2O delayed to 20 min, over a period of 2 h. In both fresh and salt water, initial values of paO2 and AaDO2 were regained by the end of the period of observation when a delayed PEEP was applied. The intrapulmonary right to left shunt, which increased to 40% of the cardiac output, fell by a half within 10 min of beginning PEEP ventilation, initial values being regained at 120 min. During the period of apnoea the arterial partial pressure of carbon dioxide almost doubled, and, when the tidal volume remained unaltered, was still some 20-30% above initial values at the end of 2 h despite the use of PEEP. Normal paCO2 levels were achieved on increasing the tidal volume by a factor of 1.4. The larger tidal volume had no influence on either the degree of shunt or the paO2. The effective compliance, which was considerably reduced after near drowning, increased again with the use of delayed PEEP ventilation. On beginning respiratory resuscitation there was an initial tachycardia and, despite a fall in stroke volume, an increase in mean arterial pressure and cardiac output because of the previous hypoxia. Only minimal cardio circulatory changes, and no change in oxygen availability, occurred secondary to the use of PEEP.

Animals↗
PubMed1981

[Practical-clinical aspects in primary clearing of the upper respiratory tract in newborn (author's transl)].

There are contradictory descriptions in the literature about the methods as well as the sequence of clearing the upper respiratory tract of new-born babies. In order to clarify this problem anatomical, physiological and pathophysiological aspects of the fetal and neonatal respiratory system are described. Intrauterine asphyxia can lead to aspiration of amniotic fluid (containing meconium, squamous epithelium, lanugo hair). During delivery the fetal airway is cleared by compression of the thorax. Through suction of the mouth, throat and nose--in exactly this defined sequence--before birth of the thorax, aspiration of potentially damaging material can be prevented. The particular problem associated with meconium-steined amniotic fluid is described.

Amniotic Fluid↗
PubMed1981

[Substrate and energy metabolism in intensive care patients under long-term mechanical ventilation].

In eight polytraumatized ventilated surgical patients studies on substrate utilization and energy expenditure were performed for six days following trauma, while receiving our routinely administered parenteral diet containing 1 g amino acids/kg/d and 6.4 g carbohydrate/kg/d. The results obtained from this study indicate that we can not meet energy and substrate requirements using this infusion regimen in severely injured intensive care patients. Within the entire period of investigation all patients demonstrated the typical signs of a disturbed posttraumatic metabolism. This fact was underlined by permanently elevated glucose blood levels, low respiratory quotients - indicating mainly fatty acid oxidation - and clearly negative nitrogen balances.

Adolescent↗
PubMed1981

[A clinical study of co2-elimination using a modified bain-system (author's transl)].

Of three groups of anaesthetized and intubated patients (n = 7) under controlled ventilation two received fresh gas flows of 70 ml/kg . min, 100 ml/kg . min and 130 ml/kg . min either in increasing or in decreasing amounts via a Bain circuit, while the third group was ventilated via a conventional semi-closed anaesthesia circuit. Blood gas analyses and cardiovascular parameters were recorded. In one patient temperatures and relative humidities of in- and expired gases were obtained by psychrometry. A modification of the Bain system afforded control of respiratory minute volumes and airway pressures. CO2-elimination proved to be adequate at a fresh gas flow of 130 ml/kg. min. At 100 ml/kg. min it was acceptable still, however pH values were outside normal range. With 70 ml/kg . min mean capillary pCO2 values (42.6 mmHg and 43.2 mmHg) and mean pH values (7.32 and 7.33) in the two respective groups proved a respiratory acidosis. Capillary pO2 was above 100 mmHg in all groups. Temperature and relative humidity of inspired gases were 24 degrees C and 40 per cent, 23 degrees C and 25 per cent, 22 degrees C and 3 per cent at fresh gas flows of 70, 100 and 130 ml/kg . min respectively.

Adult↗
PubMed1981

[Protein and energy metabolism in intensive care patients].

30 intensive-care surgical patients were randomly divided into two groups. Metabolic substrates, nitrogen balance, energy balance, and gaseous exchange were measured. Both groups were investigated under the following conditions: 1. our routinely administered parenteral diet (1.5 g amino acid . kg-1 . d-1 and 7.6 g carbohydrate kg . d-1) 2. an infusion regimen containing an increased amount of carbohydrates, clearly exceeding energy expenditure (1.5 g amino acids . kg-1 . d-1 and 12 g carbohydrate . kg-1 . d-1) and under a two-fold aminod-acid intake (3.0 g . kg-1 . d-1 and 7.6 g carbohydrates . kg-1 . d-1). The energy expenditure of the patients in the two investigated groups averages 3000 kcal . d-1. We can cover this energy expenditure with an increased carbohydrate intake of 12 g . kg-1 . d-1. However, the data observed from the gas exchange measurements--the RQ remained still about 0.9--and urea-nitrogen excretion, suggest that even an excessive administration of carbohydrate does not totally suppress the participation of endogenous fat and protein in the oxidative energy-production process. By administering 3.0 g amino acids . kg-1 . d-1 nitrogen balance can be achieved, but leads to further elevation of BUN levels; while nitrogen excretion is not markedly increased when compared to the patients receiving 1.5 g amino acids . kg-1 . d-1. These results seem to indicate that nearly all of the high amounts of caloric substrates and amino acids are used to meet energy expenditure and nitrogen loss of intensive-care patients in the early period after trauma or severe illness, but they also serve as an additional burden for the extremely stressed metabolism in this situation.

Amino Acids↗
PubMed1980

[Aspects of primary PEEP ventilation for immediate treatment of emergency patients (author's transl)].

PEEP ventilation is frequently used in intensive care patients: its particular effects in the immediate treatment of emergency patients are discussed. In animal experiments different studies were performed using manually operated resuscitators combined with a newly designed PEEP valve. The most important results in neonatal pigs show that the post partum compliances and the neonatal PO2 values were much better after primary PEEP ventilation than after IPPB or 2-phases unfolding inflation. The worst method of respiratory resuscitation is the use of PNPB. In 2 other groups of animals immediate PEEP ventilation was compared to IPPB, after 25 ml of fresh water/kg BW had been instilled into the animals lungs. The PaO2 and AaDO2 values of those animals, treated immediately with PEEP were much better than the corresponding values of the ZEEP group animals. But, the PEEP-treated animals showed a significant reduction of the cardiac output. The article deals further with the results of different authors, as far as PEEP and lung edema, PEEP and CPR, PEEP and shock are concerned. In our opinion, the present clinical and experimental results lead to the following conclusions: The immediate PEEP ventilation at the scene is indicated 1. in neonatal resuscitation - 2. in near drowning - 3. in lung edema - 4. in cardiopulmonary resuscitation. PEEP ventilation should however not exceed 10 cm H2O.

Animals↗
PubMed1979

The influence of different ventilatory patterns on oxygenation and gas exchange after near-drowning.

After positive end-expiratory pressure (PEEP) valves for manually operated resuscitators became available it was of interest to find out whether PEEP should be applied at the scene of accident in nearly drowned patients. In 27 young pigs 25 ml of fresh water/kg body weight was instilled into the lungs via an endotracheal tube. After a period of apnoea (4 min) the pigs were ventilated artificially with 100% oxygen with either 5 cm PEEP or zero end-expiratory pressure (ZEEP). Within the PEEP group the AaDO2 returned to normal within the first 10 min after resuscitation, whereas the AaDO2 did not reach normal values for 2 h in the ZEEP group. The same observations were true for the PO2 values. Although the cardiac output decreased by almost 30% in the PEEP group, mean arterial pressures and heart rates remained unchanged. Lung weights and blood lactate concentrations confirmed that the same degree of water absorption and hypoxia had taken place in both groups. The conclusions from these experiments are that the application of 5 cm PEEP is part of the immediate measures of emergency treatment in nearly drowned victims.

Animals↗
PubMed1978

A new positive end-expiratory pressure valve for manually operated artificial ventilation.

The application of positive end-expiratory pressure (PEEP) as part of artificial ventilation is currently considered a basic provision to provide adequate treatment of critically ill patients in intensive care units. Hitherto only the application of intermittent positive pressure ventilation (IPPV) with an end-expiratory pressure of 0 cm water was possible during manually operated artificial ventilation. A new PEEP valve which can be attached to manually operated resuscitators has been developed in co-operation with industry to meet this need. The technical details and experimental testing of the new valve have been presented in this paper. It may be connected via special adaptors to existing Ambu resuscitators, either for use on adults or on neonates, babies and infants. The valve has the characteristics of normal PEEP devices in that the resistances with various PEEP levels remain relatively independent of the flow and thus presents a true positive end-expiratory pressure rather than just an increase of expiratory resistance. The valve can be connected simply to nearly all types of simple and advanced respirators, such as those used for assisting respiration, physiotherapy etc., as well as being used with manually operated resuscitators.

Adult↗
PubMed1978

[The effects of naloxone on oxygen uptake, pulmonary ventilation and cardiac performance in adult non-anaesthetised persons (author's transl)].

10 normal persons were given 0.4 milligrams of Naloxone intravenously, and the following measurements were taken: oxygen uptake, CO2 production, respiratory quotient, respiratory minute volume, tidal air, dead space, effective dead space, specific ventilation, alveolar O2 partial pressure, end-expiratory CO2 partial pressure, heart rate, systolic and diastolic blood pressure and the Burger Index. Analysis of the results established that administration of Naloxone was followed by a statistically significant, but clinically not relevant, reduction in O2 uptake and CO2 production. Higher doses produced the same results. The findings appear to contradict those observed in anaesthetised patients who are given Naloxone during the postoperative stage. However, closer examination of the results suggests that the so-called tachytrophic effect of Naloxone is attributable to its antagonistic action on the analgesic and sedative effects of opiates rather than to a specific pharmacodynamic property of Naloxone.

Adult↗
PubMed1977

[Respiratory mass spectrometer in the intensive care unit. Possibilities of application (author's transl)].

The respiratory mass spectrometer has now reached such a high degree of technical perfection, that the instrument can be used in the intensive care unit without any problems. Simultaneous and continuous analysis of respiratory and non-respiratory gases is possible. Thus a great amount of informations concerning the respiratory situation of patients can be obtained noninvasively. Simple monitoring of respiratory gases as well as lung function analysis can be performed. Problems in the field of mechanical ventilation can be solved more effectively with the help of the instrument.

Air↗