Treatment of accidental hypothermia with cardiopulmonary bypass: a case report.

This case report describes the successful treatment of severe accidental hypothermia of a 40-year-old woman. At arrival in the operating theatre her rectal temperature was 23 degrees C, her nasal temperature 21 degrees C and her periferal temperature 14 degrees C. The patient presented with a severe respiratory and metabolic acidosis which was corrected during cardiopulmonary bypass (CPB). She was rewarmed to obtain a rectal and nasal temperature of 34 degrees C. After 272 minutes, the patient was weaned successfully from CPB. The patient remained at mild hypothermia (34 degrees C) for 24 hours in the intensive care unit (ICU). The chest X-ray showed some signs of acute respiratory distress syndrome (ARDS) in spite of normal blood gas values. This improved within a few days and, after five days, she was transferred to the nursing department. On the seventh day, the patient was discharged from hospital without physical or neurological complaints.

The open lung concept: effects on right ventricular afterload after cardiac surgery.

BACKGROUND: The open lung concept (OLC) is a method of ventilation intended to maintain end-expiratory lung volume by increased airway pressure. Since this could increase right ventricular afterload, we studied the effect of this method on right ventricular afterload in patients after cardiac surgery. METHODS: We studied 24 stable patients after coronary artery surgery and/or valve surgery with cardiopulmonary bypass. Patients were randomly assigned to OLC or conventional mechanical ventilation (CMV). In the OLC group, recruitment manoeuvres were applied until Pa(o(2))/FI(O(2)) was greater than 50 kPa (reflecting an open lung). This value was maintained by sufficient positive airway pressure. In the CMV group, volume-controlled ventilation was used with a PEEP of 5 cm H(2)O. Cardiac index, right ventricular preload, contractility and afterload were measured with a pulmonary artery thermodilution catheter during the 3-h observation period. Blood gases were monitored continuously. RESULTS: To achieve Pa(O(2))/Fl(O(2)) > 50 kPa, 5.3 (3) (mean, SD) recruitment attempts were performed with a peak pressure of 45.5 (2) cm H(2)O. To keep the lung open, PEEP of 17.0 (3) cm H(2)O was required. Compared with baseline, pulmonary vascular resistance and right ventricular ejection fraction did not change significantly during the observation period in either group. CONCLUSION: No evidence was found that ventilation according to the OLC affects right ventricular afterload.

Isobutylidenediurea degradation by Rhodococcus erythropolis.

A new enzyme (isobutylidenediurea amidinohydrolase) catalyzing the hydrolysis of isobutylidenediurea (a condensation product of urea and isobutyraldehyde widely used as a slow-release nitrogeneous fertilizer) was characterized from a strain of Rhodococcus erythropolis. The enzyme was purified 1,250-fold to apparent homogeneity and shown to hydrolyze the fertilizer to urea and isobutyraldehyde at a molar ratio of 2: 1. No activity was observed with ureido- or other structurally related compounds. Its molecular mass was determined by native polyacrylamide gelelectrophoresis and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry to be 15 kDa (+/-2 kDa) and 16.4 kDa, respectively. Growth of the bacterium in the presence of isobutylidenediurea led to an increased expression of the constitutively synthetized enzyme.

Microbial urea-formaldehyde degradation involves a new enzyme, methylenediurease.

The enzymic mechanism of metabolization of urea-formaldehyde condensation products (methyleneureas; MU) and the fate of the degradation products ammonium, urea and formaldehyde were studied in bacteria isolated from garden soil, which were able to use methyleneureas as the sole source of nitrogen for growth. An organism identified as Ochrobactrum anthropi completely degraded methylenediurea (MDU) and dimethylenetriurea (DMTU) to urea, ammonia, formaldehyde and carbon dioxide. An enzyme designated as methylenediurease (methylenediurea deiminase; MDUase) was responsible for the degradation of both MDU and DMTU as well as higher polymerized MU. Growth on MU as the nitrogen source specifically induced the synthesis of this enzyme, which seems to be located in the periplasm of the bacterium. Under these growth conditions, urease as well as NAD-specific formaldehyde and formiate dehydrogenase were expressed to high levels, efficiently using the products of MU degradation, and high-affinity transport systems for urea and ammonia were synthesized scavenging the environment for these products.

Measurement of arterial pressure after cardiopulmonary bypass with long radial artery catheters.

Radial arterial pressure can significantly underestimate central aortic pressure in the postcardiopulmonary bypass (post-CPB) period. At the study institution, routine monitoring of perioperative arterial pressure in adult patients undergoing cardiac surgery is performed with a long radial artery catheter with the distal end positioned in the subclavian artery. In 68 patients presenting for elective cardiac surgery, both a conventional short radial artery catheter and a contralateral long radial artery catheter were placed. Analysis of radial and subclavian arterial pressures post-CPB in the first 47 patients showed average maximum differences of 7 mm Hg systolic and 4 mm Hg mean. In 15% of patients, the differences were clinically significant (greater than 20 mm Hg systolic and/or greater than 14 mm Hg mean). In 28 patients, central aortic pressure was measured post-CPB, and subclavian artery pressure was found to be an excellent estimator of central aortic pressure. There were no significant complications related to using long radial artery catheters in the 68 patients who were followed prospectively. Monitoring subclavian arterial pressure by percutaneous insertion of a long radial artery catheter provides a reliable estimation of central aortic pressure, even in patients with significant radial artery-to-central aortic pressure gradients post-CPB.

Practical experience with more than 60,000 closed circuit anesthesias. Traditional and future implications of the closed circuit concept.

In a twelve year period, over 60,000 anesthesias were administered using a completely closed anesthesia system. Our results show that even in these days, when the cost of anesthetic gasses and vapours are small compared to the total cost of operative medical treatment, a substantial reduction in cost is still possible by using Closed Circuit Anesthesia (CCA). During normal anesthetic practice using semi open or semi closed anesthesia systems 70% to 95% of the anesthetic gases and vapours are wasted, though this medical contribution to the environmental pollution with halogenated hydrocarbons is small compared to industrial and domestic output, we have a firm ideological standpoint in this matter, and we believe that also from this point of view we should minimise our "anesthetic wastes" as much as possible. Probably the most important reason to use CCA however is the optimal conditioning of the inspired gasses, and the increased monitoring possibilities. New promising anesthesia machines are under development, which will be able to administer CCA in a completely automatic fashion, this in contrast to the classic manually controlled and ventilated CCA systems.

Lung volume measurement during closed circuit anesthesia.

Lung volume measurement can be of interest to anesthesists as well as respiratory physicians, both as a diagnostic tool and as a way to monitor the effect of respiratory therapy (for instance PEEP ventilation). Several methods exist to measure lung volume. Only two of them can be applied easily during mechanical ventilation. The wash-in wash-out of insoluble inert gas can be used in non-rebreathing (semi open) systems, or the equilibration of an inert insoluble gas which can be used in completely closed systems. In our department a completely closed anesthesia system has been developed which is particularly well suited for the equilibration method of lung volume measurement. Just like the wash-out method, the equilibration method can give information about the uniformity of ventilation-distribution within the lung.

Transplantable canine glioma model for use in experimental neuro-oncology.

The need for a large animal tumor model in experimental neuro-oncology led us to re-evaluate and to modify the transplantable canine glioma of Wodinsky and Walker. Successive passages of the original tumor brei were made in purebred beagles, from beagle to mongrel, and between various mongrel strains until an intracerebral injection of 0.1 cc on Days 1 to 3 of life produced a 93% incidence of tumor take in all breeds. The mean survival was 13.5 +/- 1.9 days after injection (range, 10 to 19 days) in 10 litters. The tumor was invariably fatal and possessed many of the histological characteristics of human glioblastoma (i.e., capillary proliferation, pseudopallisading, frequent mitotic figures, and multinucleated giant cells). The animals were large enough to be scanned on the Pfizer 450 scanner, and the tumors were visualized in vivo as typical "ring" lesions after the injection of contrast agent. Intravital staining with Evans blue outlined the areas of contrast enhancement observed in the same tumors by computed tomography. The apparent defect in the blood-brain barrier could be explained in part by the absence of endothelial tight junctions on electron microscopy. Stability in the histology and activity of the tumor could be demonstrated after more than 14 months of storage at -70 degrees C. The transplantable canine glioma model has many advantages including low cost, reproducible morphology, a short survival time, and relative safety for the investigator. The large size of the animal preparation allows the use of complex surgical instrumentation and radiographic study, as well as repeated sampling of cerebrospinal and other fluids.

Calculated recovery rates in severe head trauma.

In a series of 120 head-injured patients, recovery rates (rr) were calculated separately on the basis of either Glasgow come scale (GCS) scores or Maryland coma scale (MCS) scores; the latter contains the three variables of the GCS, excludes unevaluable responses, and provides more information concerning the status of brain stem reflexes and motor lateralization. The early (Day 3/4 vs. Day 1) and late (Day 8/14 vs. Day 1) recovery rates from the two scales generally agree (r = 0.76; r = 0.79), but in 39 of 94 patients the MCSrr and GCSrr disagreed by more than 10%. When the MCSrr was greater than the GCSrr, it more accurately reflected a favorable outcome. Graphic representations of clinical courses through serial plots of raw scores were more reliable when unaffected by intubation, sedation, swollen eyelids, casts, etc.; this was more often achieved with serial plots of MCS scores, which are graded as percentages of testable function. Final outcomes (good/disabled vs. vegetative/dead) were well predicted by Day 1 MCS scores above or below 35% (chi 2 = 27.63; p less than 0.001) and Day 1 GCS scores above or below 7 (chi 2 = 23.21; P less than 0.001). However, in 57 very sick patients (Day 1 GCS less than or equal to 7), the GCS did no better than chance (26 good, 31 bad outcomes), whereas 20 of 26 patients with a Day 1 MCS score of less than or equal to 35% had bad outcomes. In patients with severe multiple injuries, the Maryland coma scale may provide a more sensitive index of clinical course; a Day 1 MCS raw score of less than or equal to 35% is of grave prognostic significance.