Design of an instrument for real-time detection of bioaerosols using simultaneous measurement of particle aerodynamic size and intrinsic fluorescence.

A prototype instrument has been constructed to measure individual airborne particles based on their aerodynamic size and their intrinsic fluorescence at selected excitation and emission wavelength bands. The instrument combines features of an aerodynamic particle sizing device with capabilities similar to those of a liquid flow cytometer. The goal of the instrument is to provide real-time data indicative of particle characteristics, and it is especially targeted to respond to bioaerosols from 0.5 to 10 micrometers (aerodynamic diameter) with intrinsic fluorescence exited at a wavelength of 325 nm and emitting from 420 to 580 nm. This size range covers individual airborne bacteria and bacteria clusters, and the fluorescence sensitivity is selected for biological molecules commonly found in cellular systems, for example, reduced nicotinamide adenine dinucleotide phosphate [NAD(P)H] and riboflavin. Initial tests with nebulised Bacillus subtilis var. niger (BG, ATCC 9372) spores have shown that, for both individual spores and spore clumps, a low level of fluorescence is detected from 17% of the particles. This detection percentage is on the same order as previous experiments that have measured viability of about 12% for mechanically dispersed BG spores (Ho and Fisher (1993) Defense Research Establishment Suffield Memorandum 1421) and suggests a need for further investigation into the possible relationship between the detected fluorescence and viability of bacterial spores.

Flow in sequential vein grafts with diamond anastomoses.

Flow in single grafts was compared to flow in sequential grafts with diamond anastomoses to the branches of the right and circumflex coronary arteries. The mean flow was 36 ml/min for single grafts, 51 ml/min for sequential grafts with one diamond anastomosis, and 69 ml/min for sequential grafts with two diamond anastomoses. The flow in two single grafts, 72 ml/min, was significantly more than the flow in sequential grafts with one diamond anastomosis and equalled the flow in sequential grafts with three distal anastomoses. Constructing diamond anastomoses with interrupted sutures did not significantly enhance flows in sequential grafts.

Median sternotomy infection. Management and reconstruction.

Median sternotomy infections are a difficult and potentially lethal problem. Three patients are presented who manifested variations of this clinical problem, and techniques to treat this complication are described. Successful management entails maximum debridement, elimination of mediastinal dead space utilizing omental or pectoralis major muscle flaps, adjunctive systemic antibiotics, closed irrigation systems, and reconstruction of chest wall stability.

Experience with multiple and simultaneous subclavian vein cannulations: safety and versatility.

The utilization of percutaneous catheterization of the subclavian vein has facilitated access to the central venous system and has been a valuable adjunct in the care of critically ill patients. A total of 60 patients in an intensive care setting had concurrent placement of multiple subclavian lines for fluid administration, hyperalimentation, hemodynamic monitoring, cardiac pacing, or hemodialysis over a 5-year period from 1979-84. This was done primarily because these gravely ill patients required a multitude of diagnostic and therapeutic interventions for their clinical management. Ease of applicability, versatility in use, and low morbidity for the patients were noted.

The lucid interval in stroke following carotid endarterectomy.

In 789 carotid endarterectomies, there were 39 neurologic deficits in 543 cases (7.1%) performed with a shunt and nine neurologic deficits in 246 cases (3.7%) performed without a shunt in a community where surgeons were divided and inflexible with regard to the use of shunts. In the cases performed without a shunt, seven of the nine neurologic deficits were preceded by a lucid interval, suggesting that the use of a shunt might have benefitted no more than two cases in this group. The mortality related to deficits following a lucid interval was 44 per cent, whereas the mortality of immediate deficit was 13 per cent. This supports a policy of immediate operation for stroke following a lucid interval.

The use of shunts in patients undergoing bilateral carotid endarterectomies. Help or hindrance.

A retrospective study was undertaken to help assess the influence of shunting or nonshunting in the performance of bilateral, staged carotid endarterectomies. During the years 1969 to 1979, 323 consecutive patients underwent 646 staged, bilateral carotid endarterectomies. The indications included 271 patients (83.5%) with hemispheric and nonhemispheric findings and 52 patients (16.5%) who were asymptomatic. Thirty-six patients had sustained a previous stroke. General endotracheal anesthesia and systemic heparinization were used in all operations. An indwelling shunt was used in 485 (75.1%) endarterectomies whereas 161 operations (24.9%) were done without a shunt, reflecting the surgeons' routine preferences rather than specific criteria of selection. There were 30 (4.6%) neurologic events in 29 patients. Five patients died, representing an operative mortality of 1.5 per cent. Neither carotid occlusion time, interval between operation, nor severity of extracranial occlusive disease correlated significantly with the occurrence of postoperative stroke. An analysis of the neurologic deficits revealed 27 in the shunted group (5.5%) and three in the nonshunted group (1.8%). Results of this study showed that shunting cannot be relied upon to decrease the risk of neurologic deficit and that superior results may be obtained without an indwelling shunt in performing carotid endarterectomy.

Flow in coronary artery bypass grafts to totally and partially occluded left anterior descending coronary arteries.

Flow was determined by electromagnetic flowmeter in vein bypass grafts in 20 patients with a totally occluded left anterior descending (LAD) coronary artery and on 61 patients with a partially occluded LAD. The median flow in LAD grafts was 14.5 ml/min with total LAD occlusion, and 40 ml/min with partial LAD occlusion (p less than 0.001). In cases of total LAD occlusion, the presence of mild or moderate anteroseptal wall dysfunction was associated with more satisfactory flow than was the case with severe anteroseptal wall dysfunction (p less than 0.02). Flows over 25 ml/min were found only when the LAD distal to total occlusion was 1.5 mm or greater. Unsatisfactory flows were consistently found with total LAD occlusion, poor ventricular function, and a distal LAD less than 1.5 mm. Repeat catheterizations to determine an unsatisfactory patency rate under these conditions would be necessary to alter our policy of grafting all suitable vessels beyond a total occlusion.

Control of hemoptysis by bronchial artery embolization.

Control of massive hemoptysis by embolization of bronchial arteries was achieved in two patients with bronchopleural fistula. Both patients would have been prohibitive risks for thoracotomy. The indications, contraindications, and technique of the procedure are presented as well as a review of the literature.

Application of multivariate analysis to the enzyme patterns in the serum of patients undergoing coronary artery operation.

Serial determinations of serum glutamic oxaloacetic transaminase, lactic dehydrogenase, and creatine phosphokinase were performed in 50 consecutive patients undergoing cardiac operation for coronary artery bypass or combined valve replacement and coronary artery bypass. Thirty-seven patients (74%) who demonstrated minimal or no changes on the electrocardiogram manifested a recognizable pattern of distribution of the enzyme sequences. The pattern of these patients served as controls for the detection of abnormal patterns. All other patients were grouped together, regardless of clinical behavior. Perioperative myocardial infarction was established in 5 patients (10%) and resulted in 1 death. The purpose of this study was to apply discriminant analysis to two clinically determined patient groups in order to ascertain whether the three enzyme readings can be used to classify patients into their respective groups. The results suggest that enzyme profiles reflect degrees of myocardial damage that can serve to identify clinical infarction.