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Biomedical subjects

C Byhahn

Publications and source records attributed to C Byhahn.

At least 37 records · Page 2Linked to original sources

Hemodynamics and gas exchange during carbon dioxide insufflation for totally endoscopic coronary artery bypass grafting.

BACKGROUND: In addition to single-lung ventilation (SLV), positive-pressure CO2 insufflation is mandatory for totally endoscopic coronary artery bypass grafting. Studies on the effects of unilateral CO2 insufflation on hemodynamics produced controversial results, and bilateral insufflation has not been studied to our knowledge. The present study sought to investigate hemodynamics and gas exchange during unilateral and bilateral CO2 insufflation in patients who underwent totally endoscopic coronary artery bypass grafting. METHODS: Eleven hemodynamic and gas exchange variables were monitored during 22 totally endoscopic coronary artery bypass grafting procedures with unilateral (n = 17) or bilateral (n = 5) CO2 insufflation at a pressure of 10 to 12 mm Hg. Data were obtained at baseline with double-lung ventilation, after institution of SLV, during insufflation, after cardiopulmonary bypass during SLV, and after return to double-lung ventilation. RESULTS: Arterial oxygen tension decreased significantly during SLV, whereas the peak inspiratory pressure increased. In addition, central venous pressure and heart rate increased significantly during insufflation, but mean arterial pressure remained unchanged. Although the end-tidal CO2 pressure did not change, arterial carbon dioxide tension increased progressively to a maximum of 44.6 +/- 5.9 mm Hg during unilateral insufflation, and 55.7 +/- 14.6 mm Hg during bilateral insufflation (p < 0.05 versus baseline and between groups). Mixed venous oxygen saturation declined during SLV regardless of CO2 insufflation and recovered to baseline once double-lung ventilation was restarted. Left and right ventricular ejection fractions remained unaltered. No patient required inotropic or vasopressor support. CONCLUSIONS: Carbon dioxide insufflation for totally endoscopic coronary artery bypass grafting with SLV had no adverse effects on hemodynamics. In contrast to a moderate increase of arterial carbon dioxide tension during unilateral insufflation, markedly elevated arterial carbon dioxide tension levels remain a cause of concern during bilateral insufflation.

Adult↗

Mountaineering accidents in the European Alps: have the numbers increased in recent years?

OBJECTIVE: Media reports convey the impression that the incidence of fatal accidents in the European Alps has increased. Because more specific data are lacking, we analyzed available data from the mountain rescue services in Germany, Austria, southern Tirol, Zermatt/Switzerland, and Chamonix/France from 1987 until 1997. METHODS: Information was gathered from the annual reports of the Austrian Mountain Rescue Service, the Swiss Alpine Club Rescue Station in Zermatt, the Mountain Rescue Service of the Southern Tirol Alpine Club, the Mountain Rescue Service of the Bavarian Red Cross, and the Department of Mountain Medicine and Traumatology from the Hospital in Chamonix. RESULTS: Although the total number of rescue missions and injured alpinists increased significantly during the period, the number of fatalities retrieved during such rescue missions showed no significant increase. CONCLUSIONS: Even taking into account the varying definitions of "mountain accident" used in these countries, available data from the analyzed areas of the European Alps do not demonstrate a drastic increase in the number of fatalities. In the future, data concerning mountain accidents in the European Alps should be monitored according to standard definitions and stored by the International Commission for Alpine Rescue.

Accidents↗

Occupational exposure to volatile anaesthetics: epidemiology and approaches to reducing the problem.

Long term occupational exposure to trace concentrations of volatile anaesthetics is thought to have adverse effects on the health of exposed personnel. In contrast with halothane--an agent likely to cause mutagenic effects and proven to be teratogenic--isoflurane and enflurane have not so far been proved to have adverse effects on the health of personnel exposed long term. Data on the newer agents sevoflurane and desflurane are limited. Since possible health hazards from long term exposure to inhalational anaesthetics cannot yet be definitively excluded, many Western countries have established limits for exposure. These usually range from 2 to 10 ppm as a time-weighted average over the time of exposure. A number of investigations have demonstrated that, in operating theatres with modern climate control and waste anaesthetic gas scavenging systems, occupational exposure is unlikely to exceed threshold limits. However, occupational exposure from the use of volatile agents in operating theatres with poor air control--especially during bronchoscopy procedures in paediatric patients--remains a source of concern. This also holds true for both postanaesthesia care units (PACU) and intensive care units (ICU) lacking proper air conditioning and waste gas scavengers. To minimise occupational exposure to volatile anaesthetics, all measures must be taken to provide climate control and properly working scavenging devices, and ensure sufficient personal skill of the anaesthetist, e.g. during inhalational mask induction. Furthermore, low-flow anaesthesia should be used whenever possible. The sole use of intravenous drugs such as propofol instead of volatile agents, were this possible, would eliminate occupational exposure, but may result in environmental pollution by toxic metabolites (e.g. phenol).

Anesthetics, Inhalation↗

Occupational exposure to nitrous oxide and desflurane during ear-nose-throat-surgery.

PURPOSE: To determine occupational exposure of the anesthesiologist and surgeon to nitrous oxide and desflurane during general anesthesia for ear-nose-throat (ENT) surgery in children and adults. METHODS: An observational clinical trial was performed in ten children (C) and ten adults (A). Tracheas were intubated, in adults, with cuffed tubes and in children with uncuffed tubes. The operating room was equipped with modern air conditioning and waste anesthetic gas scavengers. Gas samples were obtained during the operative procedure every 90 sec from the breathing zone of subjects. Time-weighted averages (TWA) over the time of exposure were calculated for nitrous oxide and desflurane. RESULTS: Nitrous oxide TWAs for anesthesiologists were 0.41 +/- 0.23 ppm (A) and 1.20 +/- 0.32 ppm (C, P < 0.0001), and 2.24 +/- 1.93 ppm (A) and 5.30 +/- 0.60 ppm (C, P = 0.0001) for the surgeon who worked close to the patient's airway and thus had higher exposure (P < 0.05 [A], P < 0.0001 [C]). With regard to desflurane, the anesthesiologists' TWAs were 0.02 +/- 0.03 ppm for both adults and children. The surgeon was exposed to 0.21 +/- 0.24 ppm desflurane (A) and 0.30 +/- 0.14 ppm (C, P: n.s.). Although the surgeon's exposure was greater (P < 0.05 [A], P < 0.0001 [C]), the threshold limits of 25 ppm for nitrous oxide and 2 ppm for desflurane recommended by the National Institute of Occupational Safety and Health were not exceeded. CONCLUSIONS: Under modern air conditioning, occupational exposure to inhalational anesthetics is low, and inhalational anesthesia is safe from the standpoint of modern workplace laws and health-care regulations.

Adult↗

[Ciaglia blue rhino: a modified technique for percutaneous dilatation tracheostomy. Technique and early clinical results].

OBJECTIVE: Elective tracheostomy has become an established treatment modality in modern intensive care medicine, and the number of percutaneously performed tracheostomies is steadily increasing. The Ciaglia Blue Rhino (CBR) represents another percutaneous technique in which the tracheostoma is formed by one-step dilation. Our study presents the technique itself and the early clinical experiences. METHODS: In 20 adult patients on long-term ventilation, CBR was done. After puncture of the trachea in typical manner, dilation of the tracheostoma was achieved in one single step by means of a curved dilator with a special hydrophilic coating. Then, the tracheostomy tube was inserted over a curved loading dilator. Practicability and safety were determined as well as gas exchange during the procedure by means of arterial blood gas samples. RESULTS: As a result of the dilator's hydrophilic coating, dilation of the tracheostoma was rapidly achieved within 152 +/- 22 s, virtually free from resistance of the trachea or the cervical tissues. Complications such as bleeding, aspiration or postoperative infection of the stoma were not noted in any of our patients. Fractures of isolated tracheal cartilage rings were seen in 5 patients, however, no therapeutic intervention was necessary. In terms of perioperative gas exchange, pre- and postoperative levels of FiO2, PaO2, PaCO2 and the oxygenation index (PaO2/FiO2) did not change significantly. CONCLUSIONS: Based on our early clinical experience, Ciaglia Blue Rhino represents a new method that may combine the typical advantages of each of the other techniques for percutaneous tracheostomy (i.e. Ciaglia, Griggs, Fantoni) in one single technique. This method is distinguished by a high level of safety and practicability. However, further comparative trials need to be done before a definitive judgement can be made.

Adult↗

Translaryngeal tracheostomy: two modified techniques versus the basic technique--early experience in 75 critically ill adults.

OBJECTIVES: Elective tracheostomy is an established procedure in the management of ICU patients on long-term ventilation. In addition, percutaneous tracheostomy techniques are increasingly being used. In 1997, Fantoni's translaryngeal technique (TLT), another minimally invasive procedure, was introduced. While clinical studies of TLT showed that the technique is safe and can be performed rapidly, technical difficulties which sometimes led to prolonged operating times were also noted. Our study compared the basic TLT technique to a modified TLT approach and to TLT performed with the manufacturer's new, improved "Straight Cannula" set. Twenty-five patients were enrolled in each group, and the advantages and disadvantages of the respective techniques were evaluated. SETTING: Surgical ICU of a university hospital. PATIENTS: Seventy-five adult, surgical intensive care patients. MEASUREMENTS AND RESULTS: Average operating times with the modified TLT techniques were significantly shorter, 4 and 5 min respectively, as compared to 11 min for the basic TLT technique. Initially, use of the new, improved TLT set resulted in a complete passage of the tracheal cannula in two patients; uneventful Griggs's tracheostomy was performed instead. Regardless of the technique used, no other perioperative complications were noted and the perioperative gas exchange remained unaffected by the tracheostomy procedure. CONCLUSIONS: The modified TLT procedures are safer and more readily performed than the basic technique. Difficulty in the retrograde passage of the guide wire was seen only occasionally with the modified techniques. Based on our data we conclude that the modified techniques are superior to the basic technique and represent significant progress in TLT.

Adult↗

Translaryngeal tracheostomy in highly unstable patients.

Percutaneous tracheostomy is a widely accepted and commonly performed technique for attaining long-term airway access in critically ill patients. However, severe respiratory failure and coagulopathy are relative contraindications for these procedures. We describe two patients with severe respiratory failure and inhibitor-complicated haemophilia A who underwent elective percutaneous tracheostomy performed translaryngeally, using the new Fantoni technique. Apart from two minor bleeding episodes in the haemophilic patient which were controlled promptly, no other complications occurred. If certain precautions are observed carefully, we believe that translaryngeal tracheostomy is a procedure which is superior to other percutaneous techniques and safe even in patients with severe respiratory failure and coagulopathy.

Contraindications↗

Early percutaneous tracheostomy after median sternotomy.

OBJECTIVE: Tracheostomy offers significant advantages over endotracheal intubation in patients requiring long-term assisted ventilation. However, in patients who have undergone median sternotomy, it is believed that the danger of microbial contamination and consecutive infection of the sternal wound with microbes from the tracheostomy is high when conventional tracheostomy is performed. In contrast, percutaneous techniques are less likely to result in tracheostomy infection and thus bacterial contamination of neighboring structures. Nonetheless, to date there has been no prospective study confirming or disproving this assumption. Our study evaluated outcome after percutaneous tracheostomy in patients with a median sternotomy. METHODS: A total of 144 cardiac surgical patients had elective percutaneous tracheostomy at the bedside until postoperative day 14, with 4 different techniques. Systematic microbiologic monitoring of the sternal and tracheal wounds was used. RESULTS: In 13 patients sternal wound infection was suspected, but was confirmed in only 4 (2.8%) patients who actually showed microbial contamination of the sternum. In 2 of these patients, the identified microbes were not identical to those cultured from the trachea. The other 2 patients had sternal and tracheal cultures positive for methicillin-resistant Staphylococcus aureus. Cross-contamination of the sternotomy with microbes from the patient's airways was therefore ruled out. No patient had clinical signs of tracheostomy infection. Likewise, there were no cases of mediastinitis. CONCLUSIONS: On the basis of our data, we conclude that cross-contamination of the sternal wound with microbes from the trachea is not a problem. Elective percutaneous tracheostomy is safe, even if performed during the first 14 days after median sternotomy.

Analysis of Variance↗

Percutaneous tracheostomy: ciaglia blue rhino versus the basic ciaglia technique of percutaneous dilational tracheostomy.

UNLABELLED: Percutaneous dilational tracheostomy (PDT), according to Ciaglia's technique described in 1985, has become the most popular technique for percutaneous tracheostomy and is demonstrably as safe as surgical tracheostomy. In 1999, an extensively modified technique of PDT was introduced, the Ciaglia Blue Rhino (CBR; Cook Critical Care, Bloomington, IL), that consists of one-step dilation by means of a curved dilator with hydrophilic coating. To compare CBR with the basic technique of PDT, we performed a prospective, randomized trial in 50 critically ill adults. Twenty-five of these patients had PDT, and 25 had CBR. Average operating times were <3 min for CBR (range: 50-360 s) and <7 min for PDT (range: 4-20 min; P<0.0001). Tracheostomy was successfully completed in all patients. When CBR was performed, 11 minor, nonlife-threatening complications were noted: nine fractures of tracheal cartilage and two short periods of intraoperative oxygen desaturation. During PDT, seven complications occurred, of which three were potentially life-threatening: two injuries to the posterior tracheal wall, one pneumothorax, two tracheal cartilage fractures (P< 0.05 vs CBR), one case of bleeding, and one short episode of intraoperative oxygen desaturation. Regardless of whether PDT or CBR was performed, oxygenation was not significantly affected, and there was no infection of the tracheostoma. Based on our data, we conclude that new CBR is more practicable than PDT. No life-threatening complications occurred during CBR. IMPLICATIONS: To assess practicability and safety of the Ciaglia Blue Rhino (Cook Critical Care, Bloomington, IL)-an extensively modified technique of percutaneous dilatational tracheostomy-50 critically ill adults on long-term ventilation underwent either new Ciaglia Blue Rhino or percutaneous dilatational tracheostomy in a prospective, randomized clinical trial.

Adult↗

[Exposure of anesthetists to sevoflurane and nitrous oxide during inhalation anesthesia induction in pediatric anesthesia].

Inhalational mask induction with nitrous oxide and sevoflurane in young children is an appropriate alternative to intravenous induction and is considered safe and of rapid onset. Disadvantages of this technique are environmental pollution and occupational exposure to the inhalation agents used. Moreover, the potential health hazards are not yet completely clear. The purpose of the present study was to examine the anaesthesiologist's occupational exposure to nitrous oxide and sevoflurane in paediatric anaesthesia and mask induction. Twenty children underwent inhalational induction with nitrous oxide and sevoflurane in the operating theatre (air exchange rate 20.2/h, anaesthetic waste gas scavenger 40 l/min). Anaesthesia was maintained with the same agents. Air samples were taken from the edge of the anaesthesiologist's mouth continuously every 90 seconds, and trace concentrations of nitrous oxide and sevoflurane were analyzed with a direct reading infrared spectrometer (Brüel & Kjaer 1302, Denmark). Measurements taken during anaesthesia showed an increase in the concentrations of the anaesthetics used, but these were low. The highest mean concentrations occurred during induction (3.35 +/- 4.23 ppm for sevoflurane and 37.09 +/- 11.65 ppm for nitrous oxide). The overall peak levels measured were 6.31 +/- 4.23 ppm for sevoflurane and 68.78 +/- 40.79 ppm for nitrous oxide. Though the induction period was short compared to the whole length of anaesthesia, its impact on the overall waste gas exposure was 46.3% for sevoflurane (nitrous oxide 40.6%). Nonetheless, applicable German health law regulations were never infringed. The trace concentrations measured during inhalational mask induction and maintenance of anaesthesia were very low. With regard to modern workplace laws and health care regulations, gaseous induction in paediatric anaesthesia does not threaten the personnel's health.

Air Pollutants, Occupational↗

[Occupational exposure in the hospital to laughing gas and the new inhalation anesthetics desflurane and sevoflurane].

BACKGROUND AND OBJECTIVE: There have been few studies of the occupational exposure of the new volatile anaesthetic agents desflurane and sevoflurane. Because a health risk through long-term exposure to these inhalants cannot as yet be definitely excluded, we undertook to measure the concentrations of these three anaesthetics in different parts of the Frankfurt University Medical Centre. Considering the results the relevance of exposure for surgical and anaesthesia personnel, possible consequences due to laws and possibilities of improvement were shown. METHODS: The concentration of the three anaesthetics was measured during and after 345 procedures under general anaesthesia, using photoacoustic infra-red-spectrometry every 90 sec in the breathing zone of the same operating room personnel or in the recovery room and the intensive care unit. RESULTS: Exposure of personnel in the air-conditioned operating rooms was very low, but in those rooms that were not or inadequately air conditioned was a times very high. The level of the concentrations was also significantly related to the anaesthesia system and the distance of the exposed person to the patient. The concentration of nitrous oxide was below the maximal working-place concentration (MWC) of 100 ppm, but it exceeded the threshold concentration of 0.1 MAC, as laid down in the "Maternal Protection Law" in the surgical intensive care unit and the recovery room. There are no limiting concentrations for desflurane and sevoflurane yet but their concentrations were clearly below the MWC laid down for isoflurane and enflurane. CONCLUSION: In principle the use of inhalation anaesthetics can be considered to be without occupational health risk under the present legally defined standards of air-conditioning and the requirements of a modern occupational protection law. Because of the increased concentrations in the recovery room and intensive care unit pregnant and breast-feeding women should not work in these areas.

Air Conditioning↗

[Tracheostomy in intensive care].

Tracheostomy is one of the oldest surgical procedures and in the past decades has become the method of choice in the management of patients requiring long-term mechanical ventilation. At present, several alternatives exist to conventional surgical tracheostomy, such as the percutaneous dilatational techniques according to Ciaglia (PDT), Griggs (GWDF), and Schachner (Rapitrach). In particular, PDT according to Ciaglia which was introduced in 1985, has been recognized as an equally safe, but less expensive procedure than conventional tracheostomy. Fantoni's translaryngeal percutaneous technique is another new and safe procedure, which was first performed in 1996. Nonetheless, we believe that percutaneous procedures should only be performed by experienced physicians who are well-trained in both endotracheal intubation and mask ventilation. Furthermore, the capacity to perform surgical tracheostomy immediately in case of complications should be given. Only if the contraindications are carefully observed, will these new procedures retain their value and benefit in airway management of long-term ventilated patients.

Critical Care↗

[Percutaneous tracheotomy in intensive care. Practicability and early complications of the translaryngeal Fantoni technique].

Tracheostomy is considered the airway management of choice in long-term ventilated ICU patients. In the last few years, percutaneous dilatational tracheostomy (PDT) has been established as an attractive and safe alternative to conventional open tracheostomy. Recently, there is another percutaneous technique according to Fantoni with translaryngeal airway access (TLT) available. Our study seeks to evaluate TLT in terms of complications and practicability. In 47 patients of our surgical ICU, elective TLT was performed. Mean operative time was 9.8 +/- 10.9 (range 6-27) minutes. Severe complications, such as bleeding, aspiration or infection of the tracheostoma have never been noted. A slight deterioration of arterial oxygen tension occurred in 25 patients intraoperatively, demanding to rise the concentration of inspired oxygen temporarily. However, no patient became hypoxic during the procedure. Since during the procedure gas exchange may worsen, TLT should not be employed in patients whose inspired oxygen concentration exceeds 80%. Despite the fact that severe complications associated with TLT have recently not yet been reported, physicians who perform TLT should be well-trained in the technique of conventional open tracheostomy, too. According to our present data, TLT seems to be an attractive and safe alternative to PDT. Nevertheless, for a definitive evaluation of TLT, further investigations in larger groups of patients and in the long term seem to be necessary.

Critical Care↗

Tracheostomy in cardiosurgical patients: surgical tracheostomy versus ciaglia and fantoni methods.

BACKGROUND: Patients requiring prolonged mechanical ventilation are not uncommon in a cardiosurgical intensive care unit. Elective tracheostomy is considered the airway treatment of choice in these patients. METHODS: To evaluate different techniques for tracheostomy, we prospectively investigated 120 patients who had conventional open (n = 40), minimally invasive percutaneous dilatational (n = 40), or translaryngeal (n = 40) tracheostomy techniques. The main areas of investigation included oxygenation index (partial pressure of arterial oxygen divided by fraction of inspired oxygen), complications, infection, and cost. RESULTS: The oxygenation index decreased in almost every patient, regardless of the technique used, but the extent of decrease was significantly lower in both minimally invasive techniques compared with the conventional method. Overall complication rate was 12.5% both in open tracheostomy and in percutaneous dilatational tracheostomy, whereas no complications occurred in translaryngeal tracheostomy procedures. Bacterial contamination of the tracheostomy site was found in 35% of the open tracheostomies, whereas no infection was seen in percutaneous dilatational or translaryngeal tracheostomies. In terms of costs, PDT ($506) and TLT ($362) were both much cheaper than open tracheostomy ($699). CONCLUSIONS: Percutaneous dilatational and translaryngeal tracheostomies are safe and cost-effective procedures that can be done easily at the patient's bedside and thus are attractive alternatives to conventional surgical tracheostomy in long-term airway access in a cardiosurgical intensive care unit.

Adult↗

[No contamination of medical personnel by desflurane and nitrous oxide inhalation anesthetics during surgical interventions in ophthalmology].

BACKGROUND: Possible health hazards from chronical exposure to inhalational anesthetics cannot definitively be excluded. PATIENTS AND METHODS: Trace concentrations of nitrous oxide and desflurane were continuously every 90 seconds determined in the breathing zone of both ophthalmologist and anesthesiologist during strabism surgery in 20 children by a infrared spectrometer. RESULTS: During anesthesia, the surgeon was exposed to the inhalational agents used, but concentrations were well within the legal limits. CONCLUSIONS: Despite minor occupational exposure of the operating room staff during the operative procedures, inhalational anesthesia in ophthalmologic operative procedures can be considered safe from the standpoint of modern work place laws and health care regulations.

Air Pollutants, Occupational↗

Percutaneous tracheostomy: a clinical comparison of dilatational (Ciaglia) and translaryngeal (Fantoni) techniques.

UNLABELLED: A number of percutaneous procedures for tracheostomy have been established within the last few years, among them a new technique by Fantoni using a translaryngeal approach for cannula placement. To compare the new translaryngeal tracheostomy (TLT) to the common percutaneous dilatational technique (PDT), we prospectively studied 90 patients who required elective tracheostomy. Tracheostomy was performed according to either the Ciaglia or the Fantoni technique in 45 patients at bedside. The overall complication rate was 11.1% (n = 5) in PDT, including aspiration of blood (n = 4) and severe bleeding requiring surgical intervention (n = 1). During TLT, there were technical difficulties involving guidewire placement in 31.1% (n = 14), and one patient required conversion to PDT. No other complications were noted in TLT. Regardless of the technique used, the postoperative PaO2/FIO2 ratio was slightly lower than preoperatively (P was not significant). When PDT and TLT were compared, the postoperative PaO2/FIO2 ratio was significantly lower in PDT than in TLT (P < 0.05), whereas the preoperative levels did not vary significantly between PDT and TLT. During TLT, the PaCO2 increased significantly, whereas it remained stable throughout PDT. No infection of the tracheostoma was noted in either the PDT or the TLT. We therefore consider both the PDT and the TLT equally safe and attractive techniques for establishing long-term airway access in critically ill patients. IMPLICATIONS: Elective tracheostomy is a widely accepted procedure for gaining long-term airway access. Two techniques for percutaneous tracheostomy-the established Ciaglia method and the new translaryngeal Fantoni technique-were prospectively studied for perioperative complications and practicability in 90 critically ill-patients.

Aged↗

[Ventricular rupture after blunt thoracic trauma].

In a collision with a motor-car, a pedestrian suffered multiple injuries and a blunt trauma to the thorax. Immediately after the accident, the patient was haemodynamically instable and needed resuscitation several times, without lasting success. The coroner's office found that cardiac tamponade from a ruptured right ventricle was the cause of death. The incidence of ventricular rupture due to blunt trauma in motor-car accidents is about 10 to 15%. Since definite treatment is not possible at the site of the accident, the patient must be taken immediately to a cardio-surgical hospital after initial stabilization. Unfortunately, preclinical diagnosis of ventricular rupture is difficult. In this context, the increasing availability in ambulances of a 12-channel ECG, a highly sensitive diagnostic tool, represents significant progress. Cases like the one described above should be discussed at mortality conferences of pathologists, coroners and emergency physicians to increase awareness of this problem. Only if the possibility of cardiac rupture is considered and ruled out early in cases of massive multiple injuries with haemodynamic instabilities, will decrease the apallingly high lethality figures.

Adult↗