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Biomedical subjects

M Behne

Publications and source records attributed to M Behne.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Inhalation of nitric oxide in severe lung failure].

Despite intensive therapeutic efforts, adult respiratory distress syndrome (ARDS) is still associated with a lethality ranging from 50 to 80%. Besides hypoxemia, fatal outcome is caused by myocardial insufficiency due to a progressive decrease in pulmonary vascular conductance. Inhalation of NO can selectively dilate pulmonary vessels in ventilated lung regions, thus increasing mean pulmonary artery conductance and decreasing venous admixture. This study determines the effects of NO inhalation in patients with severe ARDS on pulmonary gas exchange, haemodynamics and mortality. Twenty surgical patients (mean age 50.3 +/- 9.25 years) with severe ARDS (Murray score 3.4 +/- 0.3) were treated with variable concentrations of NO during mechanical ventilation with continuous positive pressure. Pulmonary artery catheters were used to measure pressures, flow and venous admixture. Mortality with NO inhalation was compared with that of previous ARDS patients (n = 20) who had not received NO. Mean duration of NO inhalation was 120.1 +/- 33.12 hours (n = 20) (range 40 to 254 hours). Mean NO concentration during the first hour of delivery was 18.5 +/- 3.88 ppm. Sixteen patients had FiO2 of 1.0 when NO was started. Within the first hour of NO inhalation, the PaO2/FiO2 ratio increased from 82.1 +/- 10.28 to 124.6 +/- 28.18. Eighteen patients were responders. Mean ventilatory pressure was lowered. Oxygenation improvement was most marked during the first 36 hours and then gradually declined. Despite the significant increase in NO related oxygenation, pulmonary artery pressures did not consistently decrease. Sixteen patients in the NO group died. In the group without NO 15 patients died. Compared with ARDS patients of similar severity not receiving NO, the NO-treated patients had the same lethality. In severe ARDS, oxygenation significantly improves with the initiation of NO inhalation, but this effect declines over time. With NO, FiO2 and ventilatory pressures can be lowered. Whether the theoretically reduced oxygen toxicity and the reduced invasiveness of mechanical ventilation with NO reduces patient mortality must be determined in larger patient groups.

Administration, Inhalation↗
PubMed1998

[Exposure of recovery room personnel to inhalation anesthetics].

Both desflurane and sevoflurane have a favourable blood/gas distribution coefficient. There is concern, however, that environmental contamination is higher when these agents are employed since they must be used in relatively high concentrations. Our study seeks to determine the degree of exposure of recovery room staff to trace amounts of these two agents. Two hundred and seven surgical patients were included in the study. The recovery room studied had a volume of 243 cubic metres. The hourly fresh air supply for this room was 1,845 cubic metres, which results in 7.6 air exchanges per hour without air return. Measurements of trace concentrations of the inhalational agents were taken for 12 days. Concentrations of these anaesthetics were assessed in the recovery room with a real-time infrared spectrometer every 90 seconds. Mean exposure to nitrous oxide in the recovery room was 11.5 +/- 3.97 ppm and to isoflurane 1.4 +/- 0.31 ppm. All measured values were below the standard German threshold values. Trace concentrations of desflurane were 2.8 +/- 0.84 ppm and of sevoflurane 3.2 +/- 0.62 ppm. We conclude that the exposure to the inhalational anaesthetics in the climatised recovery room was low. The threshold values of 100 ppm for nitrous oxide and 10 ppm for isoflurane recommended by German law were not exceeded. When the new volatile anaesthetics are used, exposure of recovery room staff to trace concentrations of these agents is higher, but the concentrations do not exceed the levels allowed applicable German health regulations.

Air Pollutants, Occupational↗
PubMed1998

[Diagnosis of pneumonia in long-term ventilated patients. Value of digital luminescence radiography in comparison with clinical and microbiological monitoring].

PURPOSE: Pulmonary infection is one of the most feared complications in patients receiving long-term ventilation. We evaluated prospectively the diagnostic value of daily bedside chest radiography performed as digital luminescence radiography (DLR) in comparison to clinical findings and quantitative microbial culture. MATERIAL AND METHODS: Prospective evaluation of daily bedside chest radiography (DLR) and clinical parameters such as blood count, body temperature, and microbiological monitoring (quantitative culturing, microscopy) of 20 patients receiving long-term ventilation was undertaken. Altogether 325 chest radiographs were evaluated. RESULTS: 96% of the routine radiographs showed abnormal findings. Nosocomial pneumonia was suspected in 31% of all 330 days of observation by means of clinical and microbiological findings. DLR showed correct findings in 80% of this days (right-positive interpretation); a false-positive interpretation was resulted in 16 radiographs. Most common finding in nosocomial pneumonia was an alveolar pattern with air bronchogram. Fever and leucocytosis often precede radiological evidence of pneumonia. CONCLUSION: Daily bedside chest radiography performed as DLR shows abnormal finding in a high percentage. Bedside chest radiograph is in accordance to clinical and microbiological finding of nosocomial pneumonia in 80%.

Adult↗
PubMed1998

[Safety aspects of bronchoalveolar lavage in risk patients in childhood--continuous end-expiratory pCO2 monitoring].

Although bronchoalveolar lavage (BAL) is a useful tool even in childhood pulmonary diseases, only little is known about the problems attendant to its use. Hence, we investigated from a total of 212 rigid bronchoscopy procedures 22 patients of 1-10 years of age. General inhalation anaesthesia was performed and BAL was carried out using a paediatric standardised protocol. BAL volume was adjusted to body weight. Before BAL and 2, 7 and 20 minutes after BAL capillary blood gas, blood pressure, heart rate and SaO2 were measured. Continuously end-tidal PCO2 (ET (PCO2) measurement was done by using a catheter placed in the main stream bronchus. Mean ET PCO2 increased from 39.6 +/- 9.5 mmHg to 45.7 +/- 6.87 mmHg. Concomitantly mean capillary PCO2 increased from 46.68 +/- 10.7 mmHg to 50.1 +/- 10.47 mmHg. Correlation of ET PCO2 compared to cap PCO2 was good (r = 0.89). One patient showed desaturation up to 72% another patient hypercapnia up to 77 mmHg. We conclude that generally speaking BAL is a safe procedure, even in high-risk patients. Complications are minor and of little consequence to the patient. However, severe unforeseen events may occur. Therefore, bronchoscopy and bronchoalveolar lavage should not be performed without availability of an intensive-care unit.

Anesthesia, General↗
PubMed1997

Role of quantitative cultures and microscopic examinations of endotracheal aspirates in the diagnosis of pulmonary infections in ventilated patients.

Endotracheal aspirates (EA) from 20 intubated patients in a surgical intensive care unit (mean ventilation time/patient = 16.5 days) were investigated serially by performing quantitative cultures using growth of 10(5) cfu/mL as a cut-off point. Microscopic examinations were made using Giemsa's stain for polymorphonuclear neutrophils (PMN). The spectrum of pathogens encountered was determined and compared with clinical data to distinguish colonization from infection of the lower respiratory tract. Out of 301 EA cultures, 156 (51.8%) were positive and 145 (48.2%) were below the cut-off point. Counts of PMN were significantly higher in samples which gave positive cultures. Seventy-five different bacterial strains were isolated (64% were Gram-negative bacilli). Seventeen patients (85%) were colonized with Gram-negative bacteria. Nine patients (45%) developed nosocomial pneumonia (NP), five (25%) had no signs of pneumonia, and six (30%) had an uncertain status. Main causative agents for NP were Pseudomonas aeruginosa, Enterobacteriaceae and Staphylococcus aureus. Quantitative EA cultures had a sensitivity of 81.5%, a specificity of 64.8%, a positive predictive value of 55% and a negative predictive value of 87%. Our results suggest that EA quantitative cultures (cut-off value 10(5) cfu/mL), species identification and microscopic examination of EA may help to differentiate tracheobronchial colonization and infection, especially when bronchoscopic techniques are not available.

Adult↗
PubMed1995

[Prevention of myocardial ischemia. Study following aortocoronary bypass operation with the calcium antagonist diltiazem].

The incidence of postoperative myocardial infarction (MI) is proportional to the incidence of myocardial ischaemic episodes. Therefore, the prevention of such episodes is of great clinical importance. METHODS. In 90 patients undergoing coronary artery bypass grafting (CABG), perioperative i.v. treatment with either nitroglycerin (NTG), diltiazem (DIL), or the combination of DIL/NTG was used until arrival in the intensive care unit. Myocardial ischaemic episodes were monitored with an automatic ECG-ST-trend analyser (Marquette 7010). RESULTS. Significantly less ischaemic episodes were seen in the DIL group (6.7%) compared to the NTG group (13.2%) or DIL/NTG group (13.5%). Furthermore, significantly less ischaemic episodes were associated with relevant haemodynamic alterations in the DIL group (58.1%) compared to the NTG (89.1%) or DIL/NTG group (80.0%). Increases in heart rate were markedly reduced in the DIL group. DISCUSSION. DIL results in marked haemodynamic stabilisation during CABG, especially in the period immediately after extra-corporeal circulation. This might serve as an explanation for the significant reduction in ischaemic episodes in the DIL group compared to the other two groups. Therefore, perioperative prevention of myocardial ischaemia with the calcium antagonist DIL seems to be favourable in patients during CABG.

Adult↗
PubMed1995

Role of pericardial constraint for right ventricular function in humans.

STUDY OBJECTIVE: To analyze the extent of pericardial constraint on right ventricular function in humans. PATIENTS AND METHODS: Twenty patients, 59 +/- 2 (mean +/- SEM) years old, undergoing coronary bypass surgery. Right ventricular volumes and pressures were evaluated using a rapid response Swan-Ganz thermodilution catheter. INTERVENTIONS: Parameters were determined before and after pericardiotomy, both before and during increased right ventricular systolic pressure by partial compression of the pulmonary artery (before pulmonary compression: 25 +/- 1 mm Hg; during: 39 +/- 1 mm Hg). RESULTS: Pericardiotomy alone did not significantly affect right ventricular end-diastolic volume (before: 79 +/- 4 mL m-2; after: 78 +/- 3 mL m-2), right ventricular ejection fraction (before: 48 +/- 1%; after: 48 +/- 2%), and right atrial pressure (before: 4.3 +/- 0.8 mm Hg; after: 4.3 +/- 0.7 mm Hg). Before pericardiotomy, the increase in right ventricular afterload significantly increased right atrial pressure (to 5.5 +/- 0.7 mm Hg, p < 0.05) and reduced right ventricular ejection fraction (to 43 +/- 2%, p < 0.01). Right ventricular end-diastolic volume remained unchanged. After pericardiotomy, the increase in right ventricular afterload significantly increased right ventricular end-diastolic volume (to 85 +/- 3 mL m-2, p < 0.01) and also reduced right ventricular ejection fraction (to 42 +/- 2%, p < 0.01), while right atrial pressure was not significantly changed. During increased right ventricular afterload, the right ventricular diastolic pressure-volume relation was shifted rightward. CONCLUSIONS: At normal levels of right ventricular diastolic filling, the pericardium does not exert constraining effects on right ventricular function. However, with increasing levels of right ventricular preload, pericardial constraint significantly influences right ventricular function in humans.

Aged↗
PubMed1995

[Principles of analgesia and sedation].

This lecture outlines the current pharmacological concepts of sedation and analgesia in the critically ill patient requiring intensive care therapy. The primary goal is to sedate such patients so that they tolerate mechanical ventilation, as well as the therapeutic and diagnostic procedures that are routinely performed on an intensive care ward. The pharmacological regimen comprises both anxiolytic and analgesic drugs. So far, no drug combination has been identified as the ideal therapy; the standard deviation of successful analgosedation is large due to an unpredictable individual response. Because the drugs currently used are free of toxic side effects, the selection made is mainly determined by factors relating to pharmacokinetic criteria, such as short half-life of action or a predictable time of elimination. So far, the selection or combination of certain drugs has not been found to influence the patient's outcome in severe disease states such as sepsis, multiple trauma, or neurotrauma. "Good quality" of sedation and analgesia is still judged by its ability to suppress tachycardia, hypertension, hyperventilation or respiratory efforts against mechanical ventilation and the absence of increases in intracranial pressure during therapeutic manoeuvres.

Analgesia↗
PubMed1994

Respiratory effects and tolerability of Mr 2264 Cl. A new opiate partial agonist in comparison with morphine and placebo.

In this double-blind, randomised, placebo-controlled cross-over study the respiratory effects of M(r) 2264 Cl 2 x 5 mg i.v., a new partial opiate receptor agonist, were investigated and compared with the respiratory effects of morphine 2 x 10 mg i.v. and placebo. As primary end-points, the slope of the rebreathing curve (dV'/dPCO2ET) and V55 (ventilation at PCO2ET = 55 mm Hg) were determined by Read's rebreathing method. The incidence of adverse events was also documented and compared. The respiratory depression after the intravenous administration of 5 mg and 10 mg M(r) 2264 Cl was comparable to the decreased sensitivity of the respiratory centre after the 20 mg morphine i.v. In contrast to morphine, a ceiling effect of M(r) 2264 Cl was found. The tolerability of M(r) 2264 Cl was comparable to that of morphine.

Adult↗
PubMed1994

Prolongation of the QT-interval during induction of anesthesia in patients with coronary artery disease.

During induction of anesthesia in 60 patients undergoing coronary artery bypass grafting (CABG), we measured the QT-interval (QTI) in the ECG, heart rate (HR) and mean arterial pressure (MAP). Based on the HR, we corrected the QT-interval (QTcI). Prior to induction, six patients (10%) already had abnormal prolongation of QTcI (> or = 440 ms). After injection of fentanyl and vecuronium, the QTcI increased significantly (P < 0.01); to a far lesser extent after injection of hypnotics (i.e. etomidate, midazolam or propofol). Orotracheal intubation caused significant shortening of QTcI (P < 0.01). HR decreased markedly after injection of fentanyl. MAP decreased, however, only after injection of hypnotics. In the immediate post intubation period, HR and MAP increased significantly. The various hypnotics produced no significant difference in HR and QTcI at any measurement point. MAP changed only after injection of hypnotics. The decrease of HR and MAP during induction of anesthesia is thought to result from a corresponding reduction of adrenosympathetic stimulation. We believe that QTcI is similarly influenced.

Anesthesia, Intravenous↗
PubMed1994

Droperidol causes a dose-dependent prolongation of the QT interval.

To further investigate possible prolongation of the frequency-corrected QT interval (QTc interval) after administration of droperidol (DRO), we studied 40 surgical patients who were randomly assigned to one of three groups, receiving an intravenous (IV) injection of either 0.1 mg/kg (Group 1, n = 10), 0.175 mg/kg (Group 2, n = 10), or 0.25 mg/kg (Group 3, n = 20) of DRO at induction of anesthesia. The QTc interval, heart rate, and arterial pressure were registered before and 1, 2, 3, 4, 5, 7.5, and 10 min after the respective dose injection. Significant prolongations of the median QTc interval were found in patients from all groups, ranging from 37 ms (8.0%) in Group 1, to 44 ms (10.6%) in Group 2, to 59 ms (14.9%) in Group 3, when compared with control. The heart rate showed a significant increase in all groups. Mean arterial pressure (MAP) was slightly but significantly decreased in Groups 1 and 3. Prolongation of the QTc interval is a predictable and dose-dependent side effect after injection of high-dose DRO.

Blood Pressure↗
PubMed1994

[Effectiveness of preventing hypotension with H1/H2 antagonists before protamine administration].

BACKGROUND: This prospective randomized study was undertaken to evaluate the effects of prophylactic administration of H1/H2 receptor blockers on histamine release and hemodynamic changes after administration of protamine in two groups of patients (n = 20) undergoing elective coronary artery bypass graft surgery. PATIENTS AND METHODS: Group 1 (n = 10) patients were pretreated intravenously with 1 mg/kg ranitidine and 0.1 mg/kg dimetinden 15 min before termination of the extracorporeal circulation; group 2 patients (n = 10) received no medication. After termination of the extracorporeal circulation, heparin was neutralized by administration of 350 U/kg protamine, injected during 4 min via a peripheral vein. Hemodynamic measurements were carried out before the administration of protamine and at 1-min intervals up to 10 min after the injection. Before administration of protamine and 2, 4, 6, 8, and 10 min thereafter, plasma histamine levels were measured using central venous blood samples. RESULTS: In group 1 patients, who were treated prophylactically with H1/H2 receptor blockers, the plasma histamine concentration was 0.21 +/- 0.15 ng/ml (mean +/- SD) and reached a peak value of 0.30 +/- 0.17 ng/ml within 4 min. In group 2 patients, the plasma histamine concentration increased from 0.17 +/- 0.15 to 0.26 +/- 0.24 ng/ml after 10 min. The hemodynamic reactions were comparable in both groups (group 1: decrease in systolic arterial pressure from 118 +/- 16 to 104 +/- 15 mm Hg; group 2: from 111 +/- 19 to 108 +/- 21 mm Hg; differences statistically not significant). The Spearman rank correlation revealed no statistically significant relationship between the slight plasma histamine release and clinically severe decreases of blood pressure that were observed in single patients. CONCLUSION: Histamine release appears unlikely as the mechanism of protamine-induced hypotension. Therefore, general prophylaxis using H1/H2 receptor antagonists does not seem to be justified and cannot be recommended.

Aged↗
PubMed1993

[Comparative study of blood and infusion heaters at various flow-through rates].

BACKGROUND: Transfusions of refrigerator-temperature blood, particularly when given very quickly, may induce severe hypothermia. In Germany, blood warmers used to avoid this danger mainly operate with dry heat. MATERIAL AND METHODS: In the current study we compared the Fenwal BW-5 (Travenol), the Biotest BW 385 and BW 385L (Biegler) and the DW 1220 (American Pharmaseal) at different flow rates of packed cells and Ringer Lactate solution, respectively. RESULTS: Up to flow rates of about 30 ml/min higher transfusion temperatures were reached by the Biotest BW 385L than by other warmers. Above flow rates of about 60 up to about 100 ml/min only the Fenwal BW-5 reached a transfusion temperature higher than 30 degrees C. CONCLUSIONS: For routine transfusions and infusions the Biotest BW 385L is the most suitable warmer. If a massive transfusion is necessary, it is recommendable to use two or three Fenwal BW-5 or to apply other technologies.

Blood Flow Velocity↗
PubMed1993

[ST segment changes in the ECG. Anesthesia induction with propofol, etomidate or midazolam in patients with coronary heart disease].

Induction of anaesthesia with propofol and fentanyl can lead to marked reductions in mean arterial pressure (MAP) and heart rate (HR). Thus, the application of propofol in patients with severely reduced coronary artery perfusion is controversial. METHODS. The study group consisted of 60 patients undergoing coronary artery bypass grafting (CABG). Anaesthesia was induced over 30 s with propofol (P 1.5 mg/kg), etomidate (E 0.3 mg/kg), or midazolam (M 0.15 mg/kg) following a bolus dose of fentanyl (5 micrograms/kg). Vecuronium was used as a muscle relaxant. During induction we continuously measured MAP and HR and recorded the occurrence of myocardial ischaemia using an automatic ST-segment analyser (Marquette 7010). ST-segment deviations of more than 1 mm in leads II and V5 were interpreted as significant signs of myocardial ischaemia. RESULTS. All groups showed reductions in MAP and HR on induction that were marked in the P group. Intubation caused elevation of MAP and HR to pre-induction levels (HR: all groups) or slightly above (MAP: E, M). Four patients in the P group and 3 in each other group showed significant ST-segment deviation prior to induction. In the P group these deviations disappeared in 2 patients after injection while they remained unchanged in the M group. In the E group injection had no effect on the ischaemic ECG changes but produced another case of significant ST-segment deviation. Laryngoscopy and intubation produced no further significant ST-segment deviation in either group. DISCUSSION. Induction is a critical phase of anaesthesia, especially in patients with limited coronary reserve. Induction agents should alleviate the stress response while causing minimal haemodynamic changes. Despite marked reductions in MAP in the P group, the number of patients with ischaemic ECG changes was cut by half. Their number was unchanged or even raised in the other groups. After application of P, with an alleged reduction of coronary perfusion, a compensational reduction in myocardial oxygen consumption may occur.

Aged↗
PubMed1991

[Characteristics of the QT interval in the ECG following reconstructive surgery of the common carotid artery].

In 40 patients undergoing thrombendarterectomy of the common carotid artery, the frequency-corrected QT interval in the ECG, as well as the serum sodium, potassium and total calcium were studied. Examination took place preoperatively 1.-3. hour postoperative and the 1. and 5. day postoperative. In 13 patients, pathological prolongation of QT interval (greater than 440 msec) was already found pre-operatively. Postoperative significant QT interval prolongations could not be found in any patient, independent of the site of operation or pre-operative findings. The total serum calcium concentration was postoperatively significantly reduced (P less than 0.01). There was no correlation between the reduced total serum calcium and the QT interval in the ECG. The findings contradict the assumption that clinically relevant reduction of the autonomous cardial innervation is frequent in patients undergoing thromboendarterectomy of the common carotid artery.

Aged↗
PubMed1991

[Thiamine deficiency as a cause of life threatening lactic acidosis in total parenteral nutrition].

Two patients aged 37 and 44 years developed life-threatening lactic acidosis following abdominal surgery and a period of about 3 weeks of total parenteral nutrition. Septicaemia and hypoxia were excluded as possible causes. Conventional treatment including high doses of buffer agents was unsuccessful. Thiamine (vitamin B1) depletion was suspected as the cause of the metabolic acidosis, and two doses of 400 mg thiamine were given. In both patients, the lactic acidosis improved immediately, and it disappeared following the second dose of thiamine. Both patients were subsequently discharged as symptom-free. As part of the pyruvate-dehydrogenase (PDH) complex, thiamine was capable of improving the life-threatening situation.

Acid-Base Equilibrium↗
PubMed1991

[The effect of flumazenil on alfentanyl-induced respiratory depression].

Use of the benzodiazepine antagonist flumazenil may inhibit the effects of benzodiazepines in a competitive manner. The only known partially agonistic effect of flumazenil is a weak anticonvulsive action at high doses. However, reports have claimed that flumazenil reduces the MAC of isoflurane in animal studies. Other reports have found that antagonizing midazolam-induced sedation or anesthesia by flumazenil led to an increase in respiratory depression. The aim of this study was to examine whether flumazenil i.v. increases fentanyl-induced respiratory depression. METHODS. In two separate sessions, ten healthy young volunteers were given either 0.0027 mg/kg fentanyl alone or 0.0027 mg/kg and 1 mg flumazenil i.v. over 4 min each time. The CO2 rebreathing method was used to determine the ventilatory response. RESULTS. Fentanyl alone brought about a significant reduction in CO2 response, characterized by a shift to the right and a decrease in the slope of the rebreathing curve (from 1.95 +/- 0.76 l.min-1.mmHg-1 to 0.86 +/- 0.53 l.min-1.mmHg-1). The infusion of additional flumazenil caused similarly significant respiratory depression (from 2.21 +/- 1.0 l.min-1.mmHg-1 to 0.77 +/- 0.38 l.min-1.mmHg-1). In both groups changes persisted for at least 120 min. No statistically significant differences between the two groups could be detected. CONCLUSION. Flumazenil does not enhance fentanyl-induced respiratory depression. Flumazenil's weak, partially agonistic action is therefore of no clinical importance.

Adult↗