Biomedical subjects

F Konrad

Publications and source records attributed to F Konrad.

At least 19 recordsLinked to original sources

PubMed1998

[The effect of total intravenous anesthesia with propofol, alfentanil and vecuronium (TIVA) on bronchial mucosal transport].

PURPOSE: The mucociliary escalator of the lung is an important protective transport system by means of which inhaled particles and microorganisms are removed from the tracheobronchial system. In the present prospective study the effect of total intravenous anaesthesia with propofol, alfentanil, vecuronium, and oxygen-air ventilation on bronchial mucus transport velocity (BTV) was investigated. METHOD: 10 patients undergoing major abdominal surgery were included in the study. In all patients anaesthesia was induced and maintained with propofol, alfentanil, and vecuronium. Ventilation was assisted with a mixture of air and oxygen (FiO2:0.35). The BTV was measured preoperatively in the conscious patients one day before surgery while they received local anaesthesia with 10 ml of 1 percent lidocaine and after the end of the operation during intubation anaesthesia. BTV was determined with a small volume of albumin microspheres labelled with technetium -99m, which was deposited on the dorsal surface at the lower ends of the right and left main bronches via a catheter placed in the inner channel of a fibre-optic bronchoscope [7]. The study was approved by the ethics committee of our hospital. RESULTS: The administered dose of propofol was 3.0 g (1.8-5.5), of alfentanil 26 mg (20-50), and of vecuronium 20 mg (16-34) (median with range). The duration of mechanical ventilation up to the time of measurement was 5 h (3.0-9.5). TIVA produced a decrease of BTV in the right (9.7 vs 4.9 mm/min) and left main bronchus (11.3 mm/min vs 5.3 mm/min). CONCLUSIONS: Total intravenous anaesthesia with propofol, alfentanil, and vecuronium depressed mucociliary flow in patients with healthy lungs. The period for recovery of mucociliary clearance and the possible disadvantage in patients with increased pulmonary risk (e.g. patients with chronic bronchitis and abdominal surgery) should be clarified in further studies.

Adult↗

PubMed1997

[Combination anesthesia and bronchial tranport velocity. Effects of anesthesia with isoflurane, fentanyl, vecuronium and oxygen-nitrous oxide breathing on bronchial mucus transport].

UNLABELLED: The mucociliary escalator of the lung is an important protective transport system by means of which inhaled particles and microorganisms are removed from the tracheobronchial system. In general, it is assumed that anaesthetics inhibit mucociliary clearance [3,5,6,19,27]. In the present prospective study the effect of combination anaesthesia with isoflurane, fentanyl, vecuronium, and nitrous oxide-oxygen mixture on bronchial mucus transport velocity (BTV) was investigated. PATIENTS AND METHODS: 10 patients undergoing major abdominal surgery were included in the study. The study was approved by the ethics committee of our hospital. In all patients anaesthesia was induced with propofol (1-2 mg/kg), fentanyl (0.2-0.3 mg/kg) and vecuronium (0.1 mg/kg). After intubation anaesthesia was maintained with 1.5 MAC isoflurane and repeated doses of fentanyl (0.1-0.2 mg) and vecuronium. Ventilation was assisted with a 2:1 mixture of nitrous oxide and oxygen. The BTV was measured preoperatively in the conscious patients one day before surgery while they received local anaesthesia with 10 ml of 1 percent lidocaine and postoperatively while they received intubation anaesthesia. BTV was determined with a small volume of albumin microspheres labeled with technetium-99m, which was deposited on the dorsal surface at the lower ends of the right and left main bronchi via a catheter placed in the inner channel of a fibre-optic bronchoscope [15]. RESULTS: Table 1 provides information about age, application of anaesthetics and duration of mechanical ventilation of the patients. The preoperative and postoperative BTV values showed no significant differences (Fig. 1). CONCLUSIONS: Combination anaesthesia with isoflurane, fentanyl, vecuronium, and O2:N2O does not influence BTV in patients with healthy lungs.

Adult↗

PubMed1996

[Combined "3-in-1"/sciatic nerve block. Block effectiveness, serum level and side effects using 700 mg mepivacaine 1% without and with adrenaline and prilocaine 1%].

UNLABELLED: A high dose of local anaesthetic is necessary for the combined "3-in-1"/sciatic nerve block. Prilocaine is recommended for its low toxicity. However, in some patients prilocaine results in pronounced methaemoglobin formation due to toludine. Little has been known hitherto about the use of high-dose mepivacaine for the combined 3-1/sciatic nerve block. This study was undertaken to compare the use of 700 mg mepivacaine 1% and of 700 mg prilocaine 1%. METHODS: The study was approved by the ethics committee of our hospital. Once their informed consent had been obtained in writing 3 x 20 patients (ASA 1-2) undergoing planned surgery on the foot or ankle joint were enrolled in the study. The patients were randomized to the following three groups on a double-blind basis: group 1,700 mg mepivacaine without epinephrine; group 2,700 mg mepivacaine with 0.2 mg epinephrine (1:350,000); group 3,700 mg prilocaine 1%. Arterial blood samples for determination of local anaesthetic serum levels were collected over a 120-min period. We determined methaemoglobin and oxygen saturation before and 120 min after the blockade and continued these measurements for 6 h in group 3. At 15-min intervals, all patients were questioned about early signs of toxicity. The perioperative monitoring including blood pressure, ECG and pulse oximetry. Data were analysed using ANOVA and Student's t-test, P < 0.05 considered statistically significant. RESULTS: The blocking efficacy did not differ among the groups (groups 1, 2, 3:90%, 95%, 90%). The maximum mepivacaine serum level in group 1 was 3.91 micrograms/ml +/- 0.95 and 2.94 micrograms/ml +/- 0.58 in group 2 (Fig. 2). Over the entire observation period the addition of epinephrine resulted in a significant reduction of the serum level (between 60.3% at t = 15 min and 19.7% at t = 120 min). In the prilocaine group the maximum serum level was 2.07 micrograms/ml +/- 0.56, significantly less than in either mepivacaine group. No patient showed signs or symptoms of local anaesthetic toxicity. In the prilocaine group there was wide variation in methaemoglobin formation among the patient, with a median of 10.1% (Fig. 3, Table 3). Three patients showed a maximum methaemoglobinemia between 16% and 17%. Five patients were still cyanotic after 6 h when they were transferred to the ward. The fractional SaO2 values amounted to 88% (median) with a minimum of 80.3%. CONCLUSION: Both mepivacaine 1% and prilocaine 1% are appropriate local anaesthetics for the combined 3-in-1/sciatic nerve block at a dose of 700 mg. There was no difference in the blocking efficacy. No patient showed clinical signs or symptoms of a local anaesthetic toxicity. Following prilocaine we are sometimes faced with high methaemoglobinemia, which may necessitate prolonged monitoring.

Adult↗

PubMed1996

[The effect of a heat and moisture exchanger (HME) on bronchial mucus transport in a closed inhalation anesthesia system].

UNLABELLED: The administration of dry anaesthetic gases for ventilation leads to morphological changes of the tracheobronchial epithelium that may cause postoperative pulmonary complications. Therefore, additional humidification with a heat and moisture exchanger (HME) is suggested for ventilation during anaesthesia, particularly when using semi-open breathing systems. Recommendations concerning the use of a HME in the semi-closed system are controversial. There are no data in the literature as to whether a HME improves mucociliary transport under these conditions. We therefore studied bronchial mucus transport velocity (BTV) with and without the use of a HME in the semi-closed circle system in humans. PATIENTS AND METHODS: The study was approved by the ethics committee of our hospital. In a prospective, randomised trial a total of 22 patients undergoing major abdominal surgery were investigated. In all patients anaesthesia was induced and maintained with midazolam, fentanyl, and vecuronium. After intubation, a HME (BACT/VIRAL HME, Pharma Systems AB, Sweden) was inserted between the endotracheal tube and ventilation tubing in 11 patients; the other 11 were ventilated without a HME and served as controls. Ventilation was assisted with a fresh flow of 3 in a semi-closed system (Dräger Sulla 808 V with an 8 ISO circle system and Ventilog 2 ventilator, Drägerwek AG, Germany) and a 2:1 mixture of nitrous oxide and oxygen. The fresh gas passed through the soda lime canister. At the end of the operation BTV was measured with a small volume of albumin microspheres labeled with technetium Tc99m, which was deposited on the dorsal surface at the lower ends of the right and left main bronchi via a catheter placed in the inner channel of a fibre-optic bronchoscope. RESULTS: The two groups were comparable with regard to age, sex, preoperative lung function, duration of mechanical ventilation, and dose of anaesthetics. There were no statistically significant differences in the BTVs. DISCUSSION: BTV does not improve with the use of a HME in the semi-closed circle system with a fresh gas flow of 31. With modern anaesthesia machines lower fresh gas flows should be administered, whereby the humidity and temperature of the inspired gases are further increased.

Adult↗

PubMed1996

[Mucociliary clearance function and medicamentous modification].

Mucociliary clearance represents a complex self-cleaning mechanism of the lung and is based on the functional unity of ciliated columnar cells and the special viscoelastic properties of the secretion produced in the tracheobronchial system. It has been known for a long time that intubation and mechanical ventilation can impair mucous transport and lead to morphological damage to the tracheobronchial mucosa. Recent studies made it clear, however, that mechanical ventilation during anaesthesia using an appropriate anaesthesiological technique has no deleterious effect on mucus transport in patients with healthy lungs. Ventilated patients in the intensive-care unit frequently have impaired mucus transport, which is associated with the development of retention of secretion and nosocomial pneumonia. In these patients a number of factors combine to form a formidable potential insult to the mucociliary transport mechanism. Numerous drugs can affect mucociliary transport. Beta-mimetics and theophylline, in particular, have a favourable effect on mucociliary transport, whereas the effect of mucolytic agents is controversial.

Adrenergic beta-Agonists↗

PubMed1995

Ultrastructure and mucociliary transport of bronchial respiratory epithelium in intubated patients.

OBJECTIVE: The objective of this study was to investigate whether reduced bronchial mucus transport velocity (BTV) is associated with a loss of cilia or ultrastructural abnormalities of cilia in intubated patients. DESIGN: The patients were studied prospectively in a convenience sample trial. SETTING: The study took place in a university hospital. PATIENTS AND PARTICIPANTS: 29 orally intubated patients in a surgical ICU. INTERVENTIONS: BTV was measured with radiolabeled microspheres in the right and left primary bronchus. Following these measurements, biopsy samples were taken from the bronchi for scanning (SEM) and transmission (TEM) electron-microscopic investigations. MEASUREMENTS AND RESULTS: SEM: Patients with normal or slight impaired BTV (group 1, n = 14: BTV: 8.5 mm/min (3.8-11.5); median with range) showed more cilia on the luminal surface than patients with markedly depressed BTV (p < 0.05) (group 2, n = 15: BTV: 0 (0-2.1)). The difference was statistically significant. The BTV values correlated moderately with the number of cilia on the luminal surface (r = 0.46; p = 0.02). TEM: In group 1, 6.5% (3.9-14.9) of cilia were abnormal (median with range) vs 9.3% (4.9-13.7) in group 2; these differences were not statistically significant. Neither was there any significant correlation between BTV and the frequency of abnormal cilia. CONCLUSIONS: Impaired mucociliary transport in intubated patients is associated with a loss of cilia rather than ultrastructural abnormalities of cilia, which are less relevant.

Adult↗

PubMed1995

[The application of n-acetylcysteine as an antioxidant and mucolytic in mechanical ventilation in intensive care patients. A prospective, randomized, placebo-controlled, double-blind study].

Oxygen radicals and oxygen radial mediators are thought to be important components in the development of acute lung injury, sepsis, and multiple organ failure. Injured patients, patients with pulmonary diseases, and multiple trauma patients also showed an elevated lipid peroxidation, indicating increased oxidant stress. N-Acetylcysteine (NAC) has been used as an antioxidant in a wide variety of experiments. NAC has been suggested to act by raising concentrations of cysteine, and hence glutathione, and by scavenging of oxidant species [1, 11, 17, 29]. The present study was designed to investigate whether the application of NAC in intubated patients has an effect on concentrations of reduced glutathione in plasma and bronchoalveolar lavage fluid (BAL) and on the lipid peroxidation products malondialdehyde and conjugated dienes. Because NAC has been widely used as a mucolytic drug for the treatment of lung diseases, the influence on tracheobronchial mucus was studied, too. METHODS. In a randomized, double-blind, placebo-controlled study, a total of 38 long-term ventilated patients of a surgical intensive care unit were investigated. Patients were treated for 5 days with either 3 g NAC/day or placebo. The plasma concentration of reduced glutathione, malondialdehyde, and conjugated dienes were measured on admission and on the 3rd and 5th days of treatment [8, 34, 48]. Additionally, the numbers of tracheobronchial suctionings were registered and chest radiographs were evaluated. A fibre-bronchoscopy was performed on admission and on the 3rd day of treatment. The amount and viscidity of tracheobronchial secretions were examined semiquantitatively, and glutathione levels were measured in the unconcentrated BAL. The study was approved by the ethics committee of the University of Ulm. RESULTS. The two groups were comparable with respect to age, sex, APACHE II score and diagnosis (Table 1). We found no significant differences in reduced glutathione levels in the plasma or in the BAL (Figs. 1, 2). Plasma concentrations of malondialdehyde were similar (Fig. 3). Only the levels of conjugated dienes were significantly higher on the 5th treatment day in the placebo group (Fig. 4). The organ function of the lung (FiO2, PEEP, PaO2), liver (SGOT, bilirubin), and kidney (creatinine) and coagulation parameters (PTT, prothrombin time, platelet count) were similar in the two groups during the time of investigation. We observed no clinically relevant differences in the tracheobronchial mucus (Table 2). CONCLUSION. The present data do not support routine use of NAC in ventilated patients, either as an antioxidant or as a mucolytic agent. Intravenous administration of 3 g NAC/day had no clinically relevant effect on glutathione levels, lipid peroxidation products, tracheobronchial mucus, and clinical condition.

APACHE↗

PubMed1994

[The effect of theophylline on the mucociliary clearance function in ventilated intensive care patients].

Mucociliary clearance represents an important protective mechanism of the upper and lower respiratory tracts whereby inhaled particles and micro-organisms are removed from the tracheobronchial system. In incubated intensive care unit (ICU) patients, impaired ciliary function and mucus transport are associated with pulmonary complications [9]. Some authors have shown that theophylline increases mucus transport in healthy subjects and patients with chronic bronchitis [8, 16, 31, 36]. However, other investigators have found unconvincing or conflicting results [4, 20, 25]. Therefore, we studied the influence of theophylline on bronchial mucus transport velocity (BTV) in ventilated ICU patients. METHODS. The study was approved by the ethnics committee of our hospital. In a placebo-controlled double-blind study, the effect of therapeutic serum concentrations (10-20 micrograms/ml) of theophylline on BTV in ventilated patients in a surgical ICU was investigated. Group 1 (n = 10) served as controls and received placebo. The patients of group 2 (n = 10) were given intravenous infusions of 5 mg/kg body weight theophylline over 20 min, followed by 1 mg/kg per hour. Before administration of theophylline and 1 h after starting the infusion BTV, serum theophylline concentrations, and arterial blood gases were measured. Heart rate and blood pressure were registered every 5 min. In an additional study, the effect of theophylline on BTV at subtherapeutic serum concentrations (5 micrograms/ml) was investigated. BTV was measured with a small volume (0.05-0.08 ml) of albumin microspheres labeled with technetium-99m, which was deposited on the dorsal surface at the lower ends of the right and left main bronchi via a catheter placed in the inner channel of a fibre-optic bronchoscope. The movement of the microspheres towards the trachea was visualised and recorded using a scintillation camera [10]. RESULTS. The theophylline treatment induced a significant improvement in BTV from 3.8 to 7.6 mm/min in the left main bronchus and from 0.5 to 5.4 mm/min in the right, while placebo was inactive. The increase in BTV, however, was associated with an increase in heart rate; in 3 patients the theophylline infusion had to be stopped because of severe tachycardia. Blood gases and blood pressures did not change. Theophylline at subtherapeutic concentrations had no effect on either BTV or heart rate. CONCLUSIONS. Theophylline at therapeutic concentrations improves bronchial mucus transport in intubated ICU patients. The increase in BTV may be associated with severe tachycardia, and therefore routine application cannot be recommended.

Adolescent↗

PubMed1994

Performance characteristics of a novel reusable intermediate-volume low-pressure cuffed endotracheal tube.

STUDY OBJECTIVE: To evaluate the performance of the reusable intermediate-volume low-pressure cuffed "Super Safety Yellow" (Willy Rüsch AG, P.O. Box 1620, D-71332 Waiblingen, Germany) endotracheal tube with regard to cuff seal, tube tip position, and incidence of postoperative throat complaints. The "Super Safety Yellow" was compared with the "Super Safety Clear" (W. Rüsch AG), the "lo-pro (Mallinckrodt Laboratories, Cornamady, Athlone County, Ireland), and the "red rubber" (W. Rüsch AG) tubes. METHODS: Two hundred adult patients scheduled for minor surgery under standardized general anaesthesia were allocated to one of these tubes. Past-cuff leakage (indicator; orally instilled 0.2% indigocarmine) as well as intratracheal tube tip position (degree of being centred) were assessed by fibre-optic tracheoscopy. The semi-standardized interviews for the recording of postoperative sore throat were performed in double-blind fashion once a day, starting on the day of operation till p.o. day 3. STATISTICS: chi 2-test; significance: P < 0.05. MAIN RESULTS: A past-cuff leakage was found in three "red rubber" tubes. There were significant differences in tube tip position with the "Super Safety Clear" being best, and the "Super Safety Yellow" being worst centred (P = 0.010). The incidence of postoperative throat complaints showed a nonsignificant tendency in favour of the PVC-tubes. A significant number of such complaints were observed in women (P = 0.0004) and in obese patients (P = 0.011). By contrast, this incidence did not significantly differ with age, tracheal cross-sectional shape, tube tip position, use of atropine, and duration of intubation. CONCLUSION: Although resembling the "red rubber" tube in the incidence of postoperative throat complaints, the "Super Safety Yellow" may be an alternative to the currently used disposable tubes in anaesthesia. Its performance is comparable with regard to cuff seal and intra-cuff pressure. Additionally, it helps in reducing PVC waste and may lessen costs.

Adult↗

PubMed1994

Mucociliary transport in ICU patients.

OBJECTIVES: The objectives of this study were to determine the bronchial mucus transport velocities in ventilated ICU patients and to study the possible role of impaired mucus transport in the development of retention of secretion and pneumonia. DESIGN: The patients were studied prospectively in a convenience sample trial. SETTING: The study took place at a university hospital. PATIENTS: Thirty-two ventilated patients in a surgical ICU were included in the study. The study was approved by the Ethics Committee of the University of Ulm. INTERVENTIONS: Bronchial mucus transport velocity (BTV) was measured with a small volume of technetium 99m-labeled albumin microspheres within the first 3 days of mechanical ventilation. The radiolabeled bolus was deposited at the distal end of the right and left main bronchus via flexible bronchoscopy. The movement of the microspheres toward the trachea was visualized and recorded using a scintillation camera. After determination of BTV, the patients were examined daily for 4 days to record pulmonary complications (defined as retention of secretion and nosocomial pneumonia). MAIN MEASUREMENTS AND RESULTS: The median BTV in the right primary bronchus was 0.8 mm/min and in the left it was 1.4 mm/min. In nine patients both radioactive drops remained at the application site. In 14 patients, a total of 19 pulmonary complications occurred (10 times retention of secretion, 9 times pneumonia). Patients with pulmonary complications had statistically significant lower BTV compared with patients without pulmonary complications; in the left bronchus 0 (0 to 6.5) mm/min (median with range) vs 3.5 (0 to 10.5) mm/min (p < 0.01) and in the right bronchus 0 (0 to 3.0) mm/min vs 4.7 (0 to 11.7) mm/min (p < 0.01). CONCLUSIONS: Ventilated patients in the ICU frequently have impaired mucus transport, which is associated with the development of retention of secretion and pneumonia.

Adult↗

PubMed1993

Studies on drug monitoring in thrice and once daily treatment with aminoglycosides.

OBJECTIVES: To investigate at what time the peak level should be determined under conventional thrice daily (t.i.d.) administration of the aminoglycoside netilmicin and to study its serum concentrations under once daily (od) treatment to define the required daily dose and to gain information about convenient drug monitoring. DESIGN: The design of the study was a consecutive sample trial. SETTING: The study took place in a university hospital. PATIENTS: 41 intubated patients of a surgical ICU who received netilmicin as a short-term infusion over 30 min for life-threatening infections were included in the study. INTERVENTIONS: In 21 patients netilmicin was administered t.i.d. The virtual peak levels which had been determined by pharmacokinetic dosage calculation were compared with the serum concentrations obtained directly after the administration as well as after 15, 30, 60 and 180 min. In 20 patients the netilmicin serum concentrations during od treatment were determined directly before and immediately after the application as well as 0.5, 1, 3, 7 and 12 h later. To achieve a virtual peak level of 25 mg/l and a trough level of 0.5 mg/l individual adjustment of the dosage based on pharmacokinetic calculations was performed. MEASUREMENTS AND RESULTS: In t.i.d. treatment the serum concentration measured after 30 min was closest to the virtual peak level; therefore, this is the best time to determine the peak level. In od treatment the required daily dose was 7.86 mg/kg body weight (median) in patients with normal renal function. During od dosing the trough level was extremely important in drug monitoring, whereas determination of the high peak level was of doubtful value. CONCLUSIONS: The peak level should be determined during t.i.d. administration at 30 min. In od treatment the initial daily dose should be 7 mg/kg body weight; in drug monitoring the trough level is very important.

Adolescent↗

PubMed1993

[A comparison of different endotracheal tubes. Tracheal cuff seal, peak centering and the incidence of postoperative sore throat].

UNLABELLED: The study objective was to evaluate cuff seal, tube tip position and incidence of postoperative sore throat in three different endotracheal tubes: the reusable Rüsch "red rubber" tube (low-volume, high-pressure cuff) and the disposable Rüsch "Super Safety Clear" and Mallinckrodt "lo-pro" tubes (both high-volume, low-pressure cuffs). METHODS: In a prospective randomized trial, 150 consecutive patients scheduled for minor orthopaedic surgery under standardized general anaesthesia, including standardized cuff pressure control, were allocated to one of the three types of endotracheal tube. Leakage and intratracheal tube tip position were investigated by means of fiberoptic tracheoscopy via the endotracheal tube, preceded by pharyngeal instillation of indigocarmine. The semi-standardized interviews for the recording of postoperative sore throat were performed once a day under double-blind conditions from the day of operation to postoperative day 3. Statistical independence testing was based on the chi 2-test, significance was assumed at P < 0.05. MAIN RESULTS: A past-cuff leakage of the pharyngeally instilled dye was found in three patients with "red rubber" tubes. In all of these cases the tracheal cross section deviated markedly from circular. The tips of the "Super Safety Clear" tubes tended to be better centred (P = 0.099). Bad tip position, however, had little influence on postoperative throat complaints (P = 0.394). The differences in incidence of postoperative throat complaints between the "red rubber" (48.9%), "Super Safety Clear" (35.6%) and "lo-pro" tubes (34.1%) did not reach the 5% level (P = 0.288). Such complaints, however, were significantly more frequent in females and in obese patients who exceeded their Broca weights by more than 25%. By contrast, postoperative throat complaints did not vary statistically significantly by age group, tracheal cross-sectional shape, use of atropine or duration of intubation. CONCLUSION: Despite the economic (usable up to 100 times) and ecological (less PVC waste) advantages of the rubber tube, the disposable tubes with high-volume, low-pressure cuffs tended to be superior regarding cuff seal, tube tip position and incidence of postoperative throat complaints. Nevertheless, the continued use of "red rubber" type reusable tubes may be justified in cases where the tube has to stay in place for only a short time.

Adult↗

PubMed1992

Measurement of mucociliary transport velocity in ventilated patients. Short-term effect of general anesthesia on mucociliary transport.

OBJECTIVES: The objectives of this study were to evaluate a method for measuring BTV in ventilated patients and to study the short-term effect of general anesthesia with midazolam, Fentanyl, pancuronium and O2:N2O on BTV. DESIGN: The study included phantom measurements on a bronchoscopy model and the determination of BTV in patients in a convenience sample trial. SETTING: The study took place in a university hospital. PATIENTS: Fourteen patients undergoing major abdominal surgery with planned postoperative mechanical ventilation were included in the study. All patients gave their written informed consent to participate in the study. INTERVENTIONS: Bronchial mucus transport velocity was measured with a small volume (0.05 to 0.08 ml) of technetium 99m-labeled albumin microspheres with an activity of 3 MBq. The radiolabeled bolus was deposited on the dorsal mucosal surface at the distal end of the right and left main bronchus via flexible bronchoscopy. The movement of the microspheres toward the trachea was visualized and recorded using a scintillation camera; quantitative evaluation utilized the condensed image. MAIN MEASUREMENTS AND RESULTS: The technique was validated in a bronchoscopy model and in an intubated patient by moving a radioactive drop in a catheter through the main bronchi at velocities from 0 to 20 mm/min. The velocities determined by the image processing technique correlated well with the data by the model and patient determination (right bronchus, r = 1.0; left bronchus, r = 1.0). In seven ventilated patients, mechanical irritation by the fiberscope produced no significant effect on BTV. The BTV was measured preoperatively in seven conscious patients one day before surgery while they received local anesthesia with 10 ml of 1 percent lidocaine and postoperatively while they received intubation anesthesia. The preoperative and postoperative BTV values showed no significant differences (10.5; 5.7 to 13.7 mm/min; vs 9.7 (3.7 to 15.3) (median with range). CONCLUSION: By this method, bronchial transport velocity can be determined in a relatively short time in ventilated patients. General anesthesia with midazolam, Fentanyl, pancuronium and O2:N2O does not influence BTV.

Adult↗

PubMed1992

New approaches in the diagnosis of pneumonia in ICU patients.

The following clinical criteria can be used for the diagnosis of pneumonia in ventilated patients: 1. New infiltrates on chest X-ray. 2. Purulent tracheal secretions (TS). 3. Positive bacteriological finding in TS. 4. Temperature over 38.5 degrees C. 5. Leucocyte count over 12,000/mm 3. 6. Characteristic auscultatory findings. 7. Impaired gas exchange. When the first three criteria are fulfilled and a further two criteria are positive, a respiratory tract infection is highly probable and therapy with antibiotics justified. When fewer criteria are fulfilled, or in cases in which specific criteria cannot be applied, for example, patients with the acute respiratory distress syndrome (ARDS), a lung contusion, or an infection located elsewhere, invasive bronchoscopic diagnosis by protected specimen brush (PSB) or bronchoalveolar lavage (BAL) is indicated. The PSB method is characterised by very good specificity, though a not so high sensitivity. Compared to the PSB method, the BAL method has a lower specificity but is more sensitive. Pre-conditions for the successful application of both methods include correct technical handling as well as close co-operation between the intensive care physician and the microbiology laboratory.

Bronchoscopy↗

PubMed1992

[Bronchoscopy for initial care following severe thoracic trauma--basically indicated?].

UNLABELLED: The study objective was to determine the usefulness of routine early (within 24 h after admission) and late (on the 3rd posttraumatic day) flexible fiberoptic bronchoscopy in patients with severe chest trauma. METHODS: By history, physical examination, and radiologic findings, we identified 15 consecutive patients, all of whom were anaesthetized, orally intubated, and mechanically ventilated. There was no change in ventilation, including FIO2, for bronchoscopy. The patients had continuous cardiovascular monitoring and peripheral pulse oximetry. The bronchoscope was inserted through a tight-fitting side port at the endotracheal tube connector. Pulse rate, mean arterial pressure, and arterial blood gases were recorded before, 1 min after, and 10 min after bronchoscopy, as were intracranial pressure (ICP) in 7 patients with an ICP probe (early bronchoscopy only) and the duration of the examination. Statistical significance was tested by means of the Wilcoxon test for correlating samples. Significance was assumed at P less than 0.05 in a two-sided test. RESULTS: Early bronchoscopy revealed two bronchial avulsions, two aspirations, and ruled out one suspected aspiration. Late bronchoscopy showed plugging of at least 3 segmental bronchi by clots in 4 patients, none of whom was able to expectorate effectively. In general, changes in the observed vital parameters were minimal. There was a significant but clinically irrelevant increase in mean pulse rate before and 1 min after early bronchoscopy. DISCUSSION: We conclude that bronchoscopy should always be considered in patients with severe chest trauma, the decision being based on typical radiological findings as well as clinical signs and symptoms. Given the proper indication, bronchoscopy supplies valuable information at minimal risk to the patient.

Adult↗

PubMed1992

[The elimination of carboxyhemoglobin--gender-specific and circadian effects].

We investigated sex-specific and circadian variations of carboxyhemoglobin (COHb) elimination in healthy volunteers. COHb elimination follows an exponential function with a baseline found in nonsmoking women at 1.72% and in nonsmoking men at 1.79% COHb saturation. During the day, the elimination half-life time (t1/2), determined by eleven hourly samples after stopping smoking was significantly (Wilcoxon-test, p less than .01) shorter in women (3.2 +/- .4 hours, mean +/- standard deviation, n = 7) than in men (4.5 +/- 0.4, n = 6). During the night, too, t1/2 calculated from 2-point measurements after the smoking halt was significantly (Wilcoxon-test, p less than .05) shorter in women (4.3 +/- 1.1, n = 4) than in men (8.0 +/- 1.6, n = 5). In men, t1/2 during the night was significantly longer (p less than .01, Wilcoxon-test) than during the day. The day/night difference may be caused by reduced alveolar ventilation during sleep. Less muscle mass and, therefore, less myoglobin as a depot for carbon monoxide may account for the shorter half-life time of carboxyhemoglobin in women. We conclude that these variations of COHb-elimination should be taken into account when a smoking halt is advised, for instance, preoperatively.

Carboxyhemoglobin↗

PubMed1991

[Carbomonoxyhemoglobin and methemoglobin in patients with and without a smoking history during ambulatory anesthesia. Consequences for the use of pulse oximetry].

Carboxyhemoglobin (COHb) and methemoglobin (MetHb) in venous blood were determined by oximetry in 1000 non-hospitalised preoperative patients. 370 of them were smokers (S), 630 non-smokers (NS). In addition, in five S we compared the oxygen saturation measured by pulse oximetry (SaO2, p) with that measured by in vitro oximetry (SaO2) and that calculated with reference to COHb (SaO2,korr). MetHb (0.66 +/- 0.21%, mean +/- standard deviation) was found to be of no relevance. COHb in S (5.12 +/- 2.25%, maximum 12.4%) was significantly higher than in NS (1.82 +/- 0.3%, range 0.9%-4.0%) and is therefore of importance in S for the oxygen transport and for the interpretation of SaO2, p, which overestimated SaO2 at a COHb level of 4.4 +/- 0.7% by 4.5 +/- 0.9%. The difference between SaO2, korr (calculated according to Forstner) differed from SaO2 by 0.66 +/- 0.5% only. We conclude that there is an indication for in vitro oximetry in non hospitalised smokers or cases of unknown smoking history. If oximetry is not available, both a reduction of O2-binding hemoglobin and an overestimation of SaO2 by pulse oximetry in an order of ten per cent should be taken into account. To compensate for dyshemoglobin fractions, pulse oximetry using more than two wavelengths is desirable.

Ambulatory Care↗

PubMed1991

[Pneumonia prevention in long-term mechanically ventilated patients: selective skin decontamination according to Stoutenbeek or prevention of colonization according to Unertl? A prospective randomized comparison of both treatments].

In a prospective randomised study, the effects of two different colonisation prophylaxis techniques on colonisation and pulmonary infection were investigated in 40 critically ill patients with long-term ventilatory support (greater than or equal to 4 days). 20 patients were selectively decontaminated with 4 x 100 g polymyxin E, 4 x 80 mg tobramycin and 4 x 500 mg amphotericin B, administered through the gastric tube and with an antimicrobial sticky paste in the oropharynx (group I). 20 patients received 50 mg of polymyxin B and 80 mg of gentamicin dissolved in 10 ml of 0.9% saline at 6 h intervals into nose, oropharynx and stomach as well as 300 mg of amphotericin B in the oropharynx only (group II). All patients received cefotaxime systemically in the first 3 days. In group I gram-negative aerobic bacteria in the pharynx decreased from 35% to 0%, in group II from 40% to 10% and in the rectum from 80% to 61% (10% in the second week) in Group I and from 100% to 73% (33% in the second week) in group II. The decrease in gram-negative microorganisms was accompanied by an increase in the frequency of Staphylococcus epidermidis. In group I, two patients developed pneumonia and two patients urinary tract infections, in group II two patients suffered from pneumonia and 3 patients urinary tract infections. Both regimes are effective methods of prophylaxis for lowering colonisation with gram-negative aerobic bacteria and the frequency of pneumonia in patients requiring long-term mechanical ventilation. A possible selection of gram-positive bacteria must be appropriately monitored.

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