Biomedical subjects
Publications and source records attributed to D Scheidegger.
Numerous anesthetic techniques and agents have been used for anesthetizing pheochromocytoma patients. However, a comparison based on literature reports is difficult, since most describe only isolated cases. We discuss current anesthetic techniques and a case report of a patient who successfully received a combined propofol-fentanyl anesthesia for pheochromocytoma resection.
An early prognosis may influence the management of severely head-injured patients. Clinical aspects (age, Glasgow Coma Score, pupil reaction) and neuroradiological findings (basal cysternes, midline shift) are the most important facts for prognosis; evoked potentials, stress parameters and the quality of resuscitation also correlate with definitive outcome. Despite a clear correlation between these single factors and outcome, prognosis during the first 48 hours remains too uncertain to justify an influence on initial management.
In-field intensive care reduces lethality and morbidity in severe trauma. We analyze and compare 400 medical helicopter rescue flights in the region of Basel and 325 medical air-rescues in the mountains of Interlaken. The presence of a physician in the helicopter is based on an interventional concept, with clinical diagnosis, monitoring and early intensive in-field care. Compared to the mountains, we find a predominance of road accidents (44%) in the region of Basel, with more head injuries (47.3%) and more polytrauma (19.4%) and thoraxtrauma (20.5%). In the mountains, with a majority of sport accidents (65.5%), pelvis and extremity injuries (73.4%) prevailed. As a consequence of inaccessible accident sites in the mountains, 23% of the rescues had to be performed by winch. An endotracheal intubation was performed in 35.5% of the patients in the Basel region, and in 11.6% in the mountains. Fixation of fractures and hemostasis was performed in both regions in 22% and 12% of the cases. In spite of high rates of severe conditions in both regions (57% in Basel, 17% in the mountains), the low mortality prior to and during air transport (2.5% in the Basel and 2.7% in the Interlaken region) confirms the necessity of the concept of early in-field intensive therapy. This concept allows good analgesia, is save and comfortable for the patients. The presence of a physician in the air rescue team has to be recommended not only for rescues in the plain, but also in the mountains.
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Cardiovascular related deaths still represent about 50% of all demises despite their decreasing incidence in the United States and in Switzerland. About two thirds of these deaths are due to ischemic heart disease in which half of the patients die outside hospital, the majority of them two hours after the first symptoms. Moreover, sudden death is the first symptom of coronary artery disease in 25% of cases. In this country few of these persons receive adequate basic life support (BLS) at the scene because a coordinated plan to teach BLS to the citizen does not yet exist in Switzerland. With the aid of specialized medical societies, the Swiss Red Cross and affiliated organizations, it is proposed to elaborate a plan to teach BLS to the general public in Switzerland on the basis of the future European guidelines for BLS.
Transesophageal echocardiography is a new, semi-invasive technique for the examination of the heart and the aorta. Within 10-15 minutes it is possible to obtain good pictures of the anatomy and function of the heart. Diagnostic indications are native and prosthetic valvular heart disease; the method is particularly suitable for visualization of endocarditic vegetations, evaluation of embolic events or congenital heart disease and assessment of aortic dissection. In the intensive care unit transesophageal echocardiography is a new window to the heart, yielding instantaneous information on cardiac status. For the anesthetist it is the first method to provide perioperative beat to beat analysis of ventricular function.
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Among the adrenergic receptor agonists, epinephrine, at alpha and beta stimulating doses, remains the drug of choice for cardiopulmonary resuscitation. However, alpha adrenergic agonists such as phenylephrine, methoxamine and dopamine (at alpha stimulating doses) result in similar success rates of resuscitation as epinephrine. In the opposite, beta adrenergic agonists, without or with only low alpha stimulating effect, such as isoproterenol or dobutamine are significantly less efficient. There are few data indicating that sodium bicarbonate improves outcome. Moreover it carries the risk of adverse effects. It may be of benefit in case of preexisting metabolic acidosis or during prolonged resuscitation with documented acidosis. Calcium remains indicated in case of hypocalcaemia, hyperkalaemia or calcium channel blocker intoxication. Severe ionized hypocalcaemia can occur after out-of-hospital cardiac arrest.
We studied prospectively 40 critically ill neurosurgical patients who required prolonged mechanical ventilation to determine the current incidence of stress-related gastroduodenal erosions and ulcers, and to assess endoscopically the efficacy of acid-reducing prophylactic treatment. Nineteen patients were randomized to receive ranitidine plus antacids if necessary to maintain gastric pH at greater than or equal to 4. The remaining 21 patients were given no drug prophylaxis. Gastric pH was significantly (p less than .001) higher in the treated group: 78% of pH readings were at greater than or equal to 4 as compared to 32% in the control group. However, after five study days, incidence and severity of stress lesions were similar in the two groups: nine patients in each group had more than five erosions, one treated patient had a gastric ulcer, and one control patient had duodenal ulcerations. No patient experienced clinically relevant upper GI bleeding. The lack of severe stress bleeding and the low ulcer rate contrast with results from earlier reports on similar patient populations. Furthermore, drug prophylaxis had no detectable benefit, as assessed endoscopically. These findings suggest that routine stress lesion prophylaxis may not be necessary in critically ill patients with comparable risk factors.
The helicopter medical team of the Basel University Hospital treated and evacuated 710 patients in 1987/88. 484 were trauma patients (68.2%) and the intensive medical care began on the accident scene in 56% of the cases. We treated 90 thoracic injuries. 58.9% of these patients needed a chest tube which was directly inserted at the emergency place in 41.4% of the cases. An endotracheal intubation was necessary for 83.8% of the patients with in-field insertion of a chest tube and for 33.9% of other injured persons. No iatrogenic complications were observed. The clinical follow-up showed less complications for infield treated patients. We conclude that in-field insertion of chest tubes, if correctly performed, is a safe procedure contributing to diminish the lethality and the morbidity of trauma patients.
999 patients were treated and evacuated by medical helicopter in the region of Basel between 1986 and 1988. 687 were trauma patients (70.5%) and among them 53.9% were directly treated on the accident scene. Mortality during the stabilization prior to transport (2.6%) and during transport (0.3%) was low. The presence of a physician in the helicopter allows fast and intensive in-field care. All life-saving procedures like endotracheal tubes (36.3%), closed intercostal drainage (7.4% of trauma patients) and cardiovascular reanimation (1.9), even hemostasis, or fixation of fractures are performed. Early in-field intensive care by medical helicopter decreases lethality and mortality and must be recommended by severe trauma.
Between 1986 and 1988, 999 patients were treated on the emergency scene, then transported with the rescue-helicopter in the Basle area. 687 were victims of a trauma (70.5%) and 287 patients were suffering from an acute internal medicine disease. We performed in-field therapy on the accident scene itself in 53.9% of all the cases. According to our scoring system the presence of a physician was absolutely necessary in 56% of all the cases. Air rescue by helicopter allows fast transportation of patients and immediate high quality intensive care. The low mortality rate during treatment before transport (2.6%) and during the transport itself (0.3%) shows that early beginning of medical treatment on the accident scene is connected to better survival chances.
While no firm recommendations are given as to when and in whom invasive monitoring should be employed, the potential risks involved in invasive monitoring are discussed. Every physician in an intensive care unit must perform a risk/benefit analysis regarding the use of invasive monitors. Aspects of these analyses are discussed with a view to assisting decision making in individual cases.
The role of gastric microbial colonization in nosocomial infections and endotoxemia was investigated prospectively in 40 neurosurgical patients requiring mechanical ventilation for greater than 48 h. Each was studied up to 7 d. Swabs from the nose and oropharynx were cultured at admission, and aspirates from the stomach and trachea were cultured daily until enteral alimentation was started. Patients were evaluated every second day for endotoxemia and coagulation activation. Of 153 gastric aspirates, 66.7% contained microorganisms at a mean quantity of 10(7) cfu/ml. Nosocomial pneumonia occurred in 15 patients, septicemia in 5, and meningitis in 1. The stomach was the evident source of infection in only 1 patient with pneumonia. Of 140 plasma samples, 12 (8.6%) from 10 patients showed detectable endotoxin levels, but there was no association between endotoxemia or coagulation activation and the presence of microorganisms in the stomach. The stomach was not an important source for nosocomial infections or endotoxemia, even in patients with high gastric pH.
A transient depression of right ventricule (RV) function following aortocoronary bypass operation is a common event. Occasionally, RV failure may be responsible for postoperative low cardiac output syndrome, cardiogenic shock or intracardiac right-left shunt. Understanding and monitoring of RV function is essential for proper management of patients during and after aortocoronary bypass operation.
Blood ionized and total calcium levels, and pH values were obtained in 12 patients who were being ventilated and given external cardiac massage after having had an out-of-hospital cardiac arrest. On admission they had marked ionized hypocalcemia, with mean ionized calcium levels of 0.67 +/- 0.22 mmol/L, (range, 0.26 to 0.89), but normal total calcium levels. There was a positive correlation between pH and ionized calcium levels (r = 0.71). Of the six patients who were successfully resuscitated, four were discharged and two died; the other six could not be resuscitated and died. By comparison, ionized and total calcium levels obtained within 3 minutes of cardiac arrest were normal in 9 patients who had cardiac arrests in the intensive care unit or during surgery. All were discharged. These data are the first to document the occurrence of severe ionized hypocalcemia after out-of-hospital cardiac arrest. Hypocalcemia appears to be time-dependent and due essentially to extracellular complexing of calcium. Further work is needed to determine whether patients who have out-of-hospital cardiac arrests can benefit from calcium administration.
We found that three tumor patients treated with mouse mAbs have T cells that recognize processed mouse Ig on autologous APC in a class II-restricted fashion, and we have shown that mouse mAbs directed against various cell surface molecules can be used as antigens to focus these T cells on an MHC class II-positive target of choice.
This study describes a general strategy to produce hybrid monoclonal antibodies that are capable of targeting human cytotoxic T lymphocytes (CTL) against any cell carrying the appropriate target antigen. This is done by fusing a HAT-sensitive, G418-resistant anti-T3 hybridoma with immune spleen cells (or with other hybridomas) that produce antibodies against the desired target antigen. In the hybrid hybridomas the reassortment of Ig heavy and light chains results in the production of bifunctional antibody molecules. Because of their double specificity, these antibodies are able to bridge human CTL to target cells and trigger cytotoxic function. We have isolated several stable hybrid hybridomas in which one specificity is against T3 and one either against HLA antigens (class II, DC-1, A3), human Ig (IgM, IgE, kappa), Toxoplasma gondii or an ovary carcinoma-associated antigen. In all of these cases we show that culture supernatants can efficiently and specifically target any CTL clone against any target cell that possesses the relevant surface antigen recognized by the antibody. Furthermore, the killing requires as little as 0.1 ng/ml of antibody, occurs at effector to target ratios comparable to those used in conventional cytotoxic assays and does not affect bystander cells. Nonspecific killing of Fc receptor-positive cells can be avoided using F(ab')2 fragments. As an example, we show that it is possible to change the major histocompatibility complex class and allospecificity of a CTL clone and target CTL against non-major histocompatibility complex antigens such as Ig, parasites and tumor-associated antigens.