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Biomedical subjects

H Benzer

Publications and source records attributed to H Benzer.

At least 37 records · Page 2Linked to original sources
PubMed1989

[Biphasic positive airway pressure (BIPAP)--a new form of augmented ventilation].

Two modes of combining spontaneous breathing and mechanical ventilation are already in use: periodic mechanical support always followed by a period of spontaneous breathing (intermittent mandatory ventilation; IMV) and mechanical support of each spontaneous breath (inspiratory assistance; IA). Biphasic positive airway pressure (BIPAP), in contrast, is based on neither of the above mentioned principles. It is rather a mixture of pressure controlled (PC) ventilation and spontaneous breathing, which is unrestricted in each phase of the respiratory cycle. The BIPAP circuit switches between a high (Phi) and a low (Plo) airway pressure level in an adjustable time sequence. At both pressure levels the patient can breathe spontaneously in a continuous positive airway pressure system (CPAP). The volume displacement caused by the difference between Phi and Plo and the BIPAP frequency (F) contribute the mechanical ventilation to total ventilation. Duration of the Phi and the Plo phases can be independently adjusted. Similar to the I:E ratio during controlled ventilation, the phase time ratio (PhTR) is calculated as the ratio between the durations of the two pressure phases. A PhTR greater than 1:1 is called IR-BIPAP. A BIPAP system can be set up either as a continuous flow system, or as a demand valve system. A continuous-flow BIPAP system consists of a high-flow CPAP system, a reservoir bag, and a pneumatically controlled membrane valve in the expiratory limb. A magnetic valve operated by an impulse generator switches between Phi and Plo, controlling the pop-off pressures of the expiratory valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1988

[High frequency ventilation with a conventional respiratory following heart surgery interventions].

This study was designed to compare the effects of Continuous Positive-Pressure Ventilation (CPPV) and, by using the same unmodified conventional ventilator, High-Frequency Positive-Pressure Ventilation (HFPPVkonv). First, CPPV and HFPPVkonv were studied in a lung model with both normal (R = 5 mbar/1/second) and elevated (R = 20 mbar/1/second) resistance. Our results indicate that in HFPPVkonv the large compressible volume of the conventional ventilator did not influence lung model ventilation at normal resistance. The adjusted (300 ml) tidal volume (VT) and the measured volume of actual expiration (270 ml) were about the same (Fig. 1). However, with elevated resistance air trapping occurred. The large compressible volume influenced model ventilation during both CPPV and HFPPVkonv (Fig. 2). As a second step we evaluated the effects of HFPPVkonv on gas exchange, airway pressure, and hemodynamics in 12 patients (aged 43-69) postoperatively after elective cardiac surgery. After a period of stabilization at the intensive care unit every patient was first ventilated with CPPV. The ventilator settings were: VT = 10-12 ml/kg, inspiratory: expiratory ratio (I:E) = 1:2, frequency (F) = 12/min, V = 60 1/min, PEEP = 5 cm, FiO2 = 40%. After 20 min of CPPV baseline measurements were made (series I). Then the initial ventilator settings of CPPV were switched to HFPPVkonv, the conventional ventilator remaining unmodified. The settings were changed as follows: I:E = 1:3, F = 60/min, V = 120 1/min, PEEP = 5 cm, FiO2 = 40%. During 60 min of HFPPVkonv variables were measured first after 20 min (series II) and again after another 40 min (series III). Minute volume had to be doubled after changing from CPPV to HPFFVkonv to achieve eucapnia. As a result of the new ventilatory settings, VT and hold showed a significant decrease (P less than 0.01) (Table 2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Artificial ventilation--where is technology going?].

Artificial ventilation plays an important role in prophylaxis and therapy of failure or malfunction of organ systems. Augmented techniques today are used as first choice methods, rather than controlled modes. Strategies for setup of ventilation parameters are necessary in order to achieve reproducible conditions. Constituent part of these strategies is an integrated monitoring which also reflects the invasiveness of the ventilator setting. Such a parameter can be derived by calculating PEEP times I/E-Ratio times FiO2 and is useful for further therapeutic decisions.

Critical Care↗
PubMed1985

[Continuous arteriovenous hemofiltration in interstitial pulmonary edema].

In a retrospective study 40 ICU patients, all underwent Continuous Arteriovenous Hemofiltration (CAVH) for acute pulmonary, acute renal insufficiency or both, were evaluated for lung function parameters and fluid balance. It could be shown that a group of patients suffering from pulmonary insufficiency and with a history of major trauma or obstetric complications mainly benefits from fluid control by means of CAVH, while diuretics were unable to perform the desired action.

Acute Kidney Injury↗
PubMed1985

[Effect of high-frequency ventilation on intracranial pressure].

The influence of respiratory frequency, tidal volume, inspiratory flow and ratio of inspiratory/expiratory time on ventilator-related intracranial pressure (ICP) fluctuations was studied in six patients with severe brain trauma. ICP fluctuations were found to be markedly reduced at frequencies of 20/min and usually eliminated at 30/min. We found an exponential correlation between ICP fluctuations and respiratory frequency, but there was no correlation between tidal volume and ICP. Central venous pressure amplitudes were found to be in linear correlation with respiratory frequency and tidal volumes as well. The amplitude of respiratory ICP fluctuations correlates with the length of expiratory time. Our findings demonstrate that artificial ventilation without ventilator-related fluctuations in ICP ("brain-protective" ventilation) may be performed by conventional volume-constant, time-cycled ventilators. To assess the therapeutic relevance of eliminating respirator-related fluctuations of the ICP course in brain-injured patients, we suggest that frequencies of 25-30/min and tidal volumes of 6-9 ml/kg body weight should be used.

Brain Injuries↗
PubMed1984

Intraoperative application of high-frequency ventilation.

High-frequency pulsation (HFP), a modified high-frequency jet ventilation (HFJV) technique, was applied intraoperatively as an alternative to conventional inter mittent positive-pressure ventilation in 16 patients undergoing major thoracic operations. Gas exchange and hemodynamic stability were maintained at a frequency of 300 cycle/min. Surgical maneuvers were easier because the lungs were almost completely immobilized.

Adult↗
PubMed1984

Improvement of cardiac preservation by preoperative high insulin supply.

Therapeutic administration of high doses of insulin achieves a shifting of metabolism to glycogenesis and glycolysis. The result is an accumulation of the myocardial glycogen stores and an improvement of glucose utilization as well. If on that basis an increased anaerobic provision of adenosine triphosphate will be maintained in the myocardium during ischemia, the myocardial cell viability during aortic cross-clamping will be saved as well. Thus a preventive insulin supply will preserve the heart from ischemic damage. Twenty patients undergoing mitral valve replacement were investigated in two randomized groups. One group received insulin (1 U/kg/hr) together with a 33% glucose infusion (0.5 gm/kg/h) and potassium (0.25 mEq/kg/hr) from the onset of anesthesia until aortic cross-clamping. The control group received Ringer's lactate at the same infusion rate. After an average ischemic time of 26 minutes, an excised papillary muscle tip was immediately plunged into liquid nitrogen and the content of adenosine triphosphate, adenosine diphosphate, and creatine phosphate was determined. The adenosine triphosphate/diphosphate quotient and the energy charge potential were calculated. The mean adenosine triphosphate content in the insulin group was 7.43 mumol/gm wet weight and was significantly (p less than 0.01) higher than that of the control group (4.28 mumol/gm). The mean ADP content was 1.43 mumol/gm in the insulin group versus 1.81 mumol/gm in the control group. The mean creatine phosphate content was again significantly (p less than 0.05) higher in the insulin group (6.70 mumol/gm) than in the control group (5.30 mumol/gm). Also, the mean adenosine triphosphate/diphosphate quotient (insulin group, 5.19; control group, 2.36) and the mean energy charge potential (insulin group, 0.919; control group, 0.851) were significantly (p less than 0.01) higher in the insulin group. It is concluded that the preventive application of high doses of insulin leads to an augmented myocardial adenosine triphosphate provision and a maintained cellular energy charge during coronary ischemia. As a result, ischemic tolerance is enhanced and myocardial protection is improved.

Adenine Nucleotides↗
PubMed1984

[Intensive medicine--and what follows? Psychosocial follow-up study of former intensive care patients].

Intensive care medicine enables the organic survival of many seriously ill patients; however, long continuing of disease and trauma itself and the addition of life supporting therapy can remain and make social readjustment difficult. In order to obtain data on the outcome of former intensive care patients we re-examined all patients for three consecutive years who had been discharged from a multidisciplinary ICU. The patients and relatives were interviewed to elucidate changes in personality, behaviour and handicaps. These data were tested on the basis of several hypotheses. 182 patients were tested. The death rate varied for the three different years between 27% up to 37% per reexamined year. 22%-32% of the former patients reported being seriously, 69%-78% reported being moderately disabled. The suicidal tendency is equal to the standard population, although dying and death become a central theme (39%). Due to the drug consumption the health status got worse in 35% of the former patients. Despite severe psychological and physical handicaps 97% were convinced of the necessity of an ICU.

Adolescent↗
PubMed1983

[A model for standardized treatment and therapeutic evaluation of severe ARDS. PIF and AaDO2 quotient with a demand-adapting respirator and a conventional respirator during ARDS].

In order to achieve a uniform, easy to teach and to manage respiratory management in severe adult respiratory distress syndrome (ARDS) a combined treatment--called "step by step scheme"--was settled. It was aimed towards a regulation of the arterial blood oxygen tension at levels between 90 and 130 mmHg and this was achieved by combination of PEEP and IRV in order to minimize the inspiratory fraction of oxygen. Nine patients underwent this schedule and Benzer's AaDO2 quotient as an estimation of lung function as well as PIF (PEEP X I:E X FiO2) as quantifying parameter for the "strength" of the respirator are calculated. AaDO2 Quotient showed no statistically significant differences but PIF performed a clearly marked day of maximum respiratory support during the clinical course. This seems to be a confirmation that a variable defined by therapeutic procedures may also be an estimation of a certain degree of sickness as a pure diagnostic parameter. In plotting AaDO2 quotient versus PIF characteristically formed loops result. These loops give some evidence about the interactions between improving or worsening ARDS and properly adjusted therapeutic efforts by means of a respirator. The diagram may be also helpful in deciding conventional respirator settings or weaning procedures and show marks, where one might consider to treat by new techniques like High Frequency Ventilation, extracorporeal devices or arteriovenous hemofiltration.

Adult↗
PubMed1983

[High frequency pulsation (HFP) enabling tracheo-broncheal suctioning without interrupting mechanical ventilation].

A new technique of tracheo-broncheal suctioning is presented which enables constant artificial ventilation with high frequency pulsation (HFP), a modification of high frequency ventilation. Beyond that the high frequency pulsation method permits ventilation of the patient with adjusted end-expiratory pressure. This technique prevents the decrease of arterial oxygen pressure which is usually seen in patients who are disconnected for some time from the respirator as well as during the suction procedure and during periods of decreased end-expiratory pressures.

Blood Gas Analysis↗
PubMed1982

[Intraoperative application of forced diffusion-ventilation (FDV)].

Forced diffusion ventilation (FDV), a modified high frequency jet ventilation (HFJV), was applied intraoperatively (mean duration: 126 min) in 14 patients (7 thoracic, 7 major abdominal surgery patients). Sufficient gas exchange could be achieved with extremely low tidal volumes (10-30 ml) at frequencies up to 1500/min. This resulted in an almost complete immobilization of the lungs allowing an excellent surgical exposure.

Abdomen↗