Influence of intraalveolar oxygen concentration on lung preservation in a rabbit model

We previously reported the use of an inexpensive screening model for lung preservation involving ventilation and perfusion of excised rabbit lungs after their preservation. We now have extended this model by perfusing the preserved lung in cross circulation with an anesthetized rabbit to permit stable reperfusion of the preserved lungs for 60 minutes. With this model we compared the results of lung preservation with the lungs inflated with nitrogen, room air, or 100% oxygen during 24 hours of hypothermic storage. Four groups of animals were studied: group 1, excision and immediate evaluation; group 2, inflation with room air and storage for 24 hours at 10 degrees C; group 3, same as group 2, with 100% oxygen for inflation during storage; group 4, same as group 2, with 100% nitrogen for inflation during storage. Assessment of the ex vivo perfused lung consisted of (1) blood gas analysis of inflow and outflow blood at 10-minute intervals; (2) continuous pulmonary artery and airway pressure monitoring; (3) measurement of pulmonary venous oxygen tension after 1 hour of reperfusion, with inflow oxygen tension adjusted to 15 mm Hg; (4) wet/dry weight ratio. We conclude that the paracorporeal circuit does not, in itself, cause lung injury over a 1-hour period; lungs preserved with nitrogen inflation rapidly became edematous and failed to function on reperfusion. Preservation with 100% oxygen inflation appears superior to inflation with room air.

Acute occupational exposure to antineoplastic agents

Antineoplastic agents may exhibit effects not only in patients therapeutically exposed, but also in health workers who prepare and administer these drugs. Concern to date has focused on long-term health consequences, including adverse reproductive outcomes, altered immunity, and increased cancer risk. The burgeoning use of these drugs for non-malignant illnesses has enlarged the health worker population at risk beyond oncology personnel to include professionals in immunology, rheumatology, nephrology, and dermatology. We report here two cases of hospital workers who experienced acute adverse health effects resulting from occupational exposure to antineoplastic drugs. We believe such acute events are under-reported, and that they demonstrate the need for physician awareness regarding their management.

Sleep in Pierre Robin syndrome

Eight patients (aged 8 to 22 years) with the Pierre Robin syndrome underwent sleep studies. Seven demonstrated significant although minor degrees of increased sleep disturbances and apneas, and less time spent in the rapid-eye-movement (REM) stage of sleep. One patient who had previously undergone mandibular corrective surgery had major sleep abnormalities (central apnea index of 81.7 although an obstructive sleep apnea index of only 1.9). The patients had small mandibles, as demonstrated by lateral cephalometric roentgenography, and mildly increased right ventricular diastolic dimensions, as shown by M-mode echocardiography. Snoring was present in all of these patients and in 13 of 22 patients questioned from our Pierre Robin clinic. We conclude that minor abnormalities in sleep, mandibular size, and right ventricular size persist well into adolescence in the majority of patients with Pierre Robin syndrome. These appear to be clinically insignificant; however, a small percentage of such patients may continue to have major sleep disturbances.

Experimental en bloc double-lung transplantation

A technique of en bloc double-lung transplantation through a median sternotomy has been developed. Hypothermic circulatory arrest was used after surface cooling in 7 puppies (mean weight, 3.1 kg; range, 1.5 to 4.1 kg). A double lung block, consisting of the two lungs, distal trachea, the main pulmonary artery, and a large cuff of left atrium, was removed from weight-matched donors. After the arrest of the circulation by inflow occlusion, bilateral pneumonectomies were performed in the recipient. The donor double-lung block was then implanted with anastomoses at the distal trachea, the posterior left atrium, and the main pulmonary artery. All animals were successfully rewarmed and had excellent hemodynamic function and gas exchange for periods of up to 24 hours. If primate experiments with long-term survival confirm these initial results, this procedure may have a role in the treatment of patients with end-stage respiratory disease but acceptable cardiac function.

Sampling for airborne fluorouracil in a hospital drug preparation area

Fluorouracil content was studied in air samples from a hospital pharmacy work area where a vertical laminar-airflow biological safety cabinet (BSC) vented into the work area was used for the preparation of antineoplastic drugs. The BSC was run 24 hours per day and used approximately 6 hours per day. During one 56-hour period and one 95-hour period, a portable pump delivering room air at 2 L/min was positioned 12 inches outside the BSC. Fluorouracil content in extracts from 0.5-micron Teflon filters housed in the pump was assayed by high-performance liquid chromatography. The assay's lower limit of fluorouracil detection was 0.2 ng/cu m air. In the 56-hour sampling period and the 96-hour sampling periods, 25.4 g and 25 g, respectively, of fluorouracil were prepared. No fluorouracil was detectable in the filter extracts. Use of an appropriate biological safety cabinet in conjunction with good aseptic technique and the recommended procedures for safe handling of antineoplastic drugs may reduce the potential for dispersal of drug into the pharmacy workroom environment.

Determination of ionised calcium by ion selective electrode is not independent of albumin concentration

The relationship of ionised calcium measurement to changes in serum total protein and albumin were studied both in vivo and in vitro. During venostasis serum ionised calcium was determined in 10 control subjects using an Orion SS20 analyser. A slight but significant increase in ionised calcium occurred only after prolonged venostasis (15 min), when gross changes in total protein and albumin were seen. The effect of albumin concentration on serum ionised calcium was studied in vitro by the dialysis technique of Payne. The increase in ionised calcium in 40 sera was 0.0198 mmol/l per 10 g albumin change. We conclude that albumin-related variation in serum ionised calcium determination required such gross changes that correction is rarely necessary in clinical practice. When gross albumin alteration occurs, the appropriate correction for the analyser used should be determined and applied.

Combination therapy with diltiazem and propranolol: precipitation of congestive heart failure

Although congestive heart failure has been reported with the combination of a beta blocker and either verapamil or nifedipine, it has not previously been reported for combination therapy that includes diltiazem. The following case documents the occurrence of clinical congestive failure in a patient with baseline left ventricular dysfunction and severe angina pectoris. Although the patients had tolerated propranolol therapy for years without difficulty, and high-dose diltiazem monotherapy with an excellent clinical response, the combination of diltiazem and propranolol resulted in the development of congestive heart failure. Thus, although generally well tolerated, given the suitable scenario of reduced left ventricular function, the combination of diltiazem and a beta blocker may adversely affect left ventricular performance.