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Biomedical subjects

J Rathgeber

Publications and source records attributed to J Rathgeber.

At least 19 recordsLinked to original sources

[Frozen shoulder--MRI-verified continuous block of suprascapular nerve].

Suprascapular nerve block may provide sufficient analgesia in painful immobilisation of the shoulder joint. In the following case report a 41 year old male presenting with adhesive capsulitis (frozen shoulder) has been treated successfully by performing continuous delivery of local anesthetics to the suprascapular nerve via catheter. The location of the catheter has been verified using MRI examination. Pain relief was quantified by using visual analog scale (VAS 1 - 10) and showed decretion from VAS 8 - 10 pre treatment to VAS 1 - 2 after insertion of the catheter and throughout five days of intensive physiotherapy, respectively. The technique of catheterization using a nerve stimulator and alternative peripheral nerve blocks are discussed. In summary, continuous suprascapular nerve block offers an advantageous alternative for pain relief in patients with frozen shoulder. It may provide better pain control and earlier discharge in the ambulatory setting than repetetive single dose blocks.

Adult↗

[Measurement of water vapour pressure in the airways of mechanically ventilated patient using different types of humidifiers].

UNLABELLED: AIM OF THE INVESTIGATION: To evaluate the performance of different types of humidifying systems (heat and moisture exchanger, HME, and heated humidifier, HH) in the tracheo bronchial airway system of intubated mechanically ventilated patients. METHODS: A heated and fast responding capacitive sensor with a time constant of 0,23 s was used to measure the water vapor pressure at different locations in the tracheo bronchial airway system of 12 patients after therapeutic bronchoscopy. The sensor was immersed in an airstream of app. 1 ml/s continuously sampled with a bronchoscope in which the working pipe and the handle have been equipped with a heating system to prevent condensation. The sampling positions were 3 cm distal of the bifurcation in the right main bronchus, 2 cm proximal of the bifurcation and at the tube connector respectively. RESULTS: Without any humidifying system there was a dramatic reduction of the climatisation index respectively increase of the pulmonary water loss index, most prominently visible at the tube connector. There were significant differences between different types of HME (Pall BB 100 vs. Medisize Hygrovent S) but no significant differences between the Hygrovent S and the HH Fisher & Paykel 630 set at 34 degrees C. In consideration of applied tidalvolumens between 550 and 950 ml, isothermic saturation has not been reached in close vicinity to the bifurcation. CONCLUSIONS: HME may differ substantially from one type to the other and should not be used as climatisation system without careful consideration of their performance data. Effective HME are equivalent to HH at 34 degrees C and may therefore also be used for long term ventilation.

Adult↗

[Climatization of anesthetic gases using different breathing hose systems].

BACKGROUND: During general anaesthesia gas climate significantly is improved by performance of low flow techniques. Gas climatisation, however, markedly also will be influenced by the temperature loss at, and corresponding water condensation within the hoses, factors which are related to the technical design and material of the patient hose system. The objective of this prospective study was to investigate 1. how anaesthetic gas climatisation during minimal flow anaesthesia is influenced by the technical design of different breathing hose systems in clinical practice. 2. to investigate, whether a sufficient gas climatisation also can be gained with higher fresh gas flows if that hose system is used, proven beforehand to optimally warming and humidifying the anaesthetic gases. METHODS: Three different systems, a conventional two-limb hosing consisting of smooth silicone hoses, a coaxial hosing, and a hosing consisting of actively heated breathing hoses, attached to a Dräger Cicero EM anaesthesia machine, were used during minimal flow anaesthesia with a fresh gas flow of 0.5 l/min. Gas temperature and absolute humidity were measured at the tapered connection between the inspiratory limb and the breathing system as well as at its connection to the endotracheal tube. The best gas climatisation was observed if heated breathing hoses were used. Thus, using this hosing, additionally gas temperature and humidity in the inspiratory limb were taken at fresh gas flow rates of 1.0, 2.0 and 4.4 l/min respectively. Measurements were performed in all groups at all general anaesthesias lasting at least 45 minutes during the lists of eight different days each. RESULTS: In minimal flow anaesthesia, with all hose systems likewise, generally an absolute humidity between 17 to 30 mgH2O/l is reached at the endotracheal tube's connector during the course of the list. Only in the first cases of the day there was a short delay of 15 to 30 minutes before reaching a humidity of at least 17 mgH2O/l. Only with heated hoses, however, humidity frequently even exceeded 30 mgH2O/l. If conventional or coaxial hosings were used, during minimal flow anaesthesia gas temperatures in an acceptable range between 23 to 30 degrees C were measured at the tube connector. With heated hoses, however, warming of the gases was excellent with gas temperatures between 28 to 32 degrees C. In minimal flow anaesthesia climatisation of the anaesthetic gases proved to be best if heated hoses were used. Thus, using heated hose systems another three trials with increasing fresh gas flow rates of 1.0, 2.0 and 4.4 l/min respectively were performed. Whereas climatisation of the anaesthetic gases still was found to be optimal with a fresh gas flow of 1.0 l/min, the humidity dropped drastically to values lower than 17 mgH2O/l at 2.0 l/min and even down to 10 mgH2O/l at a flow rate of 4.4 l/min. Gas temperatures, however, turned out to be independent of the flow and remained at 28-32 degrees C, even at a flow as high as 4.4 l/min. CONCLUSIONS: Using conventional hose systems and coaxial hosings acceptable, but not optimal climatisation of the anaesthetic gases can be gained if minimal flow anaesthesia is performed. The use of a coaxial hose system seems to lead to improved climatisation in long lasting procedures only. In routine clinical practice, however, conventional and coaxial hose systems are similar in respect to the climatisation of breathing gases. Heated breathing hoses performed markedly better in terms of climatisation of the breathing gas than the coaxial and the conventional hose system. With this hosing not only sufficient but optimal moisture and temperature values are realized. Optimal climatisation, however, only can be gained if low flow anesthetic techniques with fresh gas flows equal or less than 1 l/min are performed. With higher fresh gas flow rates the humidity decreases markedly while high gas temperatures are maintained. (ABSTRACT TRUNCATED)

Aged↗

Comparison of ventilatory and haemodynamic effects of BIPAP and S-IMV/PSV for postoperative short-term ventilation in patients after coronary artery bypass grafting.

The aim of the present multiple cross-over study was to compare the effects of biphasic positive airway pressure (BIPAP) ventilation with synchronized intermittent mandatory ventilation combined with pressure support ventilation (S-IMV/PSV) in sedated and awake patients after coronary artery bypass grafting (CABG) surgery. Twenty-four patients with no evidence of preoperative respiratory dysfunction and an uncomplicated intraoperative course were investigated. The patients were randomly assigned to one of two groups starting with either BIPAP or S-IMV/PSV mode. Haemodynamic measurements and blood gas analyses were performed during sedation with 2.0 mg kg(-1) h(-1) propofol in the primary mode, after switching to the alternative ventilatory mode, and in the primary mode again. The same sequence of measurements was repeated in awake patients who had reached extubation criteria. In awake patients, PSV was performed instead of S-IMV. Statistical analysis of data was performed using non-parametric tests. Inspiratory peak pressure increased significantly during S-IMV/PSV in sedated patients in both groups. Other ventilatory parameters did not differ significantly between BIPAP and S-IMV/PSV in both groups. Similarly, haemodynamic parameters and blood-gas analyses did not vary with the ventilatory mode. Our results demonstrate that BIPAP ventilation has comparable effects on haemodynamics and pulmonary gas exchange compared with S-IMV/PSV and PSV when used for short-term ventilatory support in patients after cardiac surgery.

Aged↗

[Rapid measurement of water vapor partial pressure at the saturation point with a new hybrid humidity sensor].

A new hybrid humidity sensor comprising a conventional capacitance humidity sensor and a planar heating element is described. Owing to its short response time of only a few milliseconds, its great measuring accuracy, large measuring range, and simplicity in handling, the sensor is suitable for measuring water vapour partial pressure in gases with rapidly changing flow and direction, e.g. in ventilated patients in the fields of anaesthesia and intensive care medicine. The small dimensions permit measurements at almost any location within the ventilation system.

Anesthesia↗

Severe accidental hypothermia: rewarming strategy using a veno-venous bypass system and a convective air warmer.

OBJECTIVE: To study a rewarming strategy for patients with severe accidental hypothermia using a simple veno-venous bypass in combination with a convective air warmer. SETTING: Eighteen beds in a university hospital intensive care unit. PATIENTS: Four adults admitted with a core temperature less than 30 degrees C. Hypothermia was caused by alcoholic intoxication in three patients and by drug overdose in one patient. MEASUREMENTS AND MAIN RESULTS: All patients were rewarmed by a venovenous bypass and in three cases a convective air warmer was also used. At a bypass flow rate of 100-300 ml/min the mean increase in core temperature was 1.15 degrees C/h (Range: 1.1-1.2 degrees C/h). One patient died 2 days after rewarming as a consequence of a reactivated pancreatitis. The other three patients survived without neurological sequelae. CONCLUSION: This rewarming technique seems safe and effective and allowed the controlled rewarming of our patients who suffered from severe accidental hypothermia

Adult↗

Determination of airway humidification in high-frequency oscillatory ventilation using an artificial neonatal lung model. Comparison of a heated humidifier and a heat and moisture exchanger.

OBJECTIVE: Thus far only few data are available on airway humidification during high-frequency oscillatory ventilation (HFOV). Therefore, we studied the performance and efficiency of a heated humidifier (HH) and a heat and moisture exchanger (HME) in HFOV using an artificial lung model. METHODS: Experiments were performed with a pediatric high-frequency oscillatory ventilator. The artificial lung contained a sponge saturated with water to simulate evaporation and was placed in an incubator heated to 37 degrees C to prevent condensation. The airway humidity was measured using a capacitive humidity sensor. The water loss of the lung model was determined gravimetrically. RESULTS: The water loss of the lung model varied between 2.14 and 3.1 g/h during active humidification; it was 2.85 g/h with passive humidification and 7.56 g/h without humidification. The humidity at the tube connector varied between 34. 2 and 42.5 mg/l, depending on the temperature of the HH and the ventilator setting during active humidification, and between 37 and 39.9 mg/l with passive humidification. CONCLUSION: In general, HH and HME are suitable devices for airway humidification in HFOV. The performance of the ventilator was not significantly influenced by the mode of humidification. However, the adequacy of humidification and safety of the HME remains to be demonstrated in clinical practice.

Artificial Organs↗

[Emergency and intensive care medicine as an interdisciplinary training requirement].

While substantial and practical qualification for medical practice within the framework of emergency medical services have to be proven by an advanced training, there are no special training programs for in-hospital emergency situations. As in the emergency room a transparent in-hospital emergency management has to be established including definite competencies to avoid time delays and inadequate treatment due to disputes about competence. Especially surgical intensive care medicine is an interdisciplinary task, requiring the participation of the surgeon as a responsible partner. Thus, the physician working in ICUs needs professional qualification and specialized knowledge as well as marked competence to co-operate. In any case the final clinical responsibility has to be taken over by physicians who not only have performed their internship on a ICU but are highly qualified in the whole range of intensive care medicine including all topics required in advanced intensive care medicine curricula.

Clinical Competence↗

[Causes of failure and dangers in the use of motor driven infusion pumps. Accidental closure of the infusion system].

UNLABELLED: Syringe drivers are used in anaesthetics, intensive care and emergency medicine to deliver small volumes of highly potent drugs with continuous, constant and reproducible flow. For early recognition of interruptions of the drug delivery caused by occlusion of the infusion system, an alarm is triggered as soon as the system pressure exceeds a certain limit. The sensitivity of this alarm depends on the flow rate, type-specific cut-off pressure and the elastic parameters of the infusion system. The sudden release of pressure built up in the system after occlusion occurred can cause delivery of an uncontrolled drug bolus and hence an additional hazard. METHODS: Six syringe drivers that are widely used in clinical practice were tested for alarm delay and bolus delivery in the event of an occlusion in the system. First, the alarm pressures at flow rates of 10, 50 and 100 ml/h were measured. Then the alarm delay time and bolus volumes post-occlusion were assessed, using a basic infusion system (syringe + single infusion set). Finally, several alterations to the system like extension, tap battery with germ filters or branching were made and their impact on alarm delay and bolus volume measured. RESULTS: Because of the great differences in alarm pressures between the devices tested, there were marked differences in the alarm delay at same flow rates. Predictably, there was an indirect proportional link between alarm delay and flow rate. Using the basic infusion system, alarm delays between 23 s and 143 min were measured. In two of the tested syringe drivers, a pressure-release mechanism is activated with the pressure alarm, which prevented bolus application. In the other devices, release of the pressure in the occluded system caused boli of 0.5-7 ml. Variations in the actual syringe volume and insertion of a second connection tube had no impact on alarm delay and bolus volume. Tap batteries, parallel running syringe drivers or trapped air in the system, however, caused marked increase in both alarm delay (107%) and bolus volume (+147%). DISCUSSION: Unidentified occlusions of the system cause grave malfunctioning of syringe drivers. While applying highly potent drugs, the discontinuation of drug delivery with subsequent bolus application can cause vital danger to the patient. As a result of the significant time delays in the pressure alarms, the devices tested do not provide sufficient protection against unrecognized system occlusion. Syringe drivers with adjustable alarm pressure can be set close to the actual infusion pressure. A further important point is that one should aim at a reduction in the elastic properties of the infusion set because of the great impact on alarm delay and bolus volume.

Equipment Failure↗

Microbiology of the swine head meat deboning process.

The microbiology of swine head meat was evaluated by comparing the levels of aerobic plate count (APC), coliforms, and Escherichia coli as well as the incidence and levels of Salmonella spp. in swine head meat harvested by either the old or a new improved procedure. Based on 144 samples (72 by each procedure), the levels of APC, coliforms, and E. coli were 4.52 +/- 0.26, 2.37 +/ 0.42, and 2.25 +/ 0.42, and log(10) CFU/g respectively, regardless of the procedure used for harvesting the meat. The incidence (27/22) versus 28/72) and MPN levels (4 to 93 versus 4 to 1100) of Salmonella spp. determined by the Bacteriological Analytical Manual (BAM) methods also were the same for meat obtained using either the old or the new procedure. The BAM method detected a higher incidence of Salmonella spp. (55/144) than other methods, PCR(38/144; BAX, Du Pont) or DNA hybridization (41/144; Gene-Trak). Time of harvesting during the processing day or site of origin of the head meat (check versus tongue versus back of head) had no effect on the incidence of Salmonella spp. The data in this study indicate that the levels of bacteria encountered in swine head meat are a reflection of the harvesting procedures themselves, as well as levels in and around the head and oral cavity of swine.

Animals↗

The influence of controlled mandatory ventilation (CMV), intermittent mandatory ventilation (IMV) and biphasic intermittent positive airway pressure (BIPAP) on duration of intubation and consumption of analgesics and sedatives. A prospective analysis in 596 patients following adult cardiac surgery.

The aim of the study was the determination of the influence of ventilation modes on the consumption of analgesics and sedatives, duration of intubation and pulmonary gas exchange. Assist/controlled mandatory ventilation (S-CMV, 123 patients), synchronized intermittent mandatory ventilation (S-IMV, 431 patients) and biphasic positive airway pressure ventilation (BIPAP, 42 patients) were compared in a prospective, controlled, open clinical trial over an 18-month period. Five hundred and ninety-six adult patients with normal pulmonary function before surgery and uneventful course following coronary artery bypass graft surgery were studied. Patients ventilated with BIPAP had a significantly shorter mean duration of intubation (10.1 h, P < 0.05) than patients treated with S-IMV (14.7 h) and S-CMV (13.2 h). In the S-CMV group, 39.9% of the patients required single or multiple doses of midazolam, but only 13.5% in the S-IMV group and 9.5% in the BIPAP group. The mean total amount of midazolam administered to these patients was significantly higher in the S-CMV group (8.8 mg) than in the S-IMV group (6.6 mg, P < 0.05) and in the BIPAP group (4.3 mg, P < 0.05). The consumption of pethidine and piritramide did not differ between S-CMV and S-IMV, but was significantly lower during BIPAP (P < 0.05). After extubation the patients' PaCO2 was highest in the S-CMV group. We conclude that ventilatory support with BIPAP reduces the consumption of analgesics and sedatives, and the duration of intubation. The possibility of unrestricted spontaneous breathing in all phases of the respiratory cycle is considered to be the reason. BIPAP seems to be an alternative to S-CMV and S-IMV in short-term ventilated patient.

Analgesics↗

Prevention of patient bacterial contamination of anaesthesia-circle-systems: a clinical study of the contamination risk and performance of different heat and moisture exchangers with electret filter (HMEF).

The microbiological contamination of 250 breathing system tubes after use in anaesthesia circle systems with reduced fresh gas flow was investigated. The lungs of 50 patients were ventilated without any filtering device between the endotracheal tube and the Y-piece. A total of 51, 49 and 100 patients, respectively, were given different types of heat and moisture exchanger with electret filters (HMEF). With no filtering device the tubing system was contaminated by microorganisms originating from the patient's tracheal secretion in 13% of the patients. In contrast, no bacterial migration into the tubing system was detected when any of the investigated HMEF-devices were used. We therefore conclude that heat and moisture exchangers with electret filters prevent contamination of the anaesthesia breathing system with microorganisms from the patients airways.

Adult↗

Airway humidification in mechanically ventilated neonates and infants: a comparative study of a heat and moisture exchanger vs. a heated humidifier using a new fast-response capacitive humidity sensor.

OBJECTIVE: To study the efficiency of a heated humidifier and a heat and moisture exchanger in mechanically ventilated neonates and infants. DESIGN: Prospective, controlled, clinical study. SETTING: University pediatric intensive care unit. PATIENTS: Forty neonates and infants who needed mechanical ventilation were enrolled in the study. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A heat and moisture exchanger and active airway humidification were alternately used in the same patients to exclude interindividual differences in airway humidification. Airway humidity was measured by a new fast-response capacitive humidity sensor which measures airway humidity with an acquisition rate of 20 Hz throughout the respiratory cycle. The humidity sensor was placed at the endotracheal tube adapter. Measurements were done at the beginning and at the end of three consecutive sessions of passive, active, and again passive airway humidification, each session lasting 6 hrs. There was no significant difference between mean inspiratory airway humidity with the heated humidifier (33.8 +/- 2.9 mg/L) and with the heat and moisture exchanger (34.0 +/- 2.6 mg/L). Moreover, the mode of airway humidification did not significantly influence body temperature or PCO2. No serious side effects such as endotracheal tube occlusion were observed. CONCLUSIONS: Passive airway humidification by a heat and moisture exchanger is effective in mechanically ventilated neonates and infants over a 6-hr period. However, the performance and safety of a heat and moisture exchanger in prolonged mechanical ventilation remain to be proven.

Costs and Cost Analysis↗