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Biomedical subjects

R B Wagner

Publications and source records attributed to R B Wagner.

At least 37 records · Page 2Linked to original sources

Highlights of the history of nonpenetrating chest trauma.

The basic principles of the pathology, physiology, diagnosis, and management of nonpenetrating chest trauma evolved to a significant degree before World War II. The advances in the past 40 years include more frequent use of endotracheal intubation, improved ventilatory assistance, better control of blood volume, antibiotics, the clinical application of blood-gas studies, diagnostic imaging, and specialized nursing and monitoring in intensive care units. Thus, the improvement in survival is not primarily attributable to operative measures but rather to enhanced supportive measures.

England↗

Pulmonary contusion. Evaluation and classification by computed tomography.

In thoracic trauma, as in all of medicine, diagnosis precedes therapy. Over the past 5 years, we have liberally used chest CT examinations to improve diagnosis in the severely injured patient. This approach has significantly increased our diagnostic yield and permitted early diagnosis and treatment of unsuspected injuries. Confidence in our method of quantitation has helped us to assess the severity of pulmonary parenchymal injuries. Correlation of the CT findings with histologic study has changed our concept of pulmonary contusion from that of interstitial disease to that of pulmonary laceration with blood pneumonia.

Contusions↗

Quantitation and pattern of parenchymal lung injury in blunt chest trauma. Diagnostic and therapeutic implications.

Sixty-nine patients with nonpenetrating pulmonary trauma were studied by chest computed tomography (CT) within 24 hours of admission. The percentage of air-space filling was quantitated and compared with the requirement for ventilatory support. Pulmonary intraalveolar hemorrhage always is gravity dependent originating at the site of injury. Utilizing CT, the patients' pulmonary status was classified into three separate clinicoradiologic groups: Grade I injury (less than 18% air-space filling, no ventilator support required), Grade II injury (18-28% air-space filling, ventilator support sometimes required), and Grade III injury (greater than 28 air-space filling, ventilator support always required). The CT quantitation correlated with clinical functional studies and was useful in the therapeutic management of nonpenetrating lung injury.

Adolescent↗

Classification of parenchymal injuries of the lung.

Pulmonary contusion, implying interstitial and alveolar injury without significant laceration, has been accepted as the primary lung injury in nonpenetrating chest trauma. Computed tomographic (CT) findings were compared with those of chest radiography in 85 consecutive patients with chest trauma in which there was a pulmonary radiodensity consistent with pulmonary contusion or patients with a history of severe chest trauma with normal parenchyma despite rib fractures, hemothorax, pneumothorax, or widened mediastinum. CT was found to be more sensitive than radiography in that 151 abnormalities (excluding rib fractures) were demonstrated on radiographs versus 423 abnormalities on CT scans, and 99 lacerations were seen on CT scans versus five on radiographs. Pulmonary lacerations were classified into four types on the basis of CT findings and mechanism of injury: compression rupture, compression shear, rib penetration, and adhesion tears. In these cases, pulmonary laceration was shown to be an integral component of the mechanism of injury in pulmonary contusion, pulmonary hematoma, pulmonary cyst or pneumatocele, or cavitation in pulmonary contusion.

Adult↗

Free rupture of the ascending aorta: successful resuscitation at a regional trauma center.

After sustaining a free rupture of the intrapericardial ascending aorta secondary to blunt chest trauma, a 27-year-old man underwent successful aortic repair. To our knowledge, this is the first time a patient has ever survived this condition. Pericardial tamponade-together with rapid transport to the hospital and an aggressive surgical approach-was a key to the recovery of effective cardiac function and successful aortic repair. Although the patient succumbed to complications 74 days after surgery, this case illustrates the possibility of longterm survival after free rupture of the ascending aorta. The following report emphasizes the technical feasibility of controlling the perforated aortic root in such cases.

Journal Article↗

In vitro and in vivo antibacterial activities of the fluoroquinolone WIN 49375 (amifloxacin).

WIN 49375 (amifloxacin) is a synthetic antibacterial agent of the quinolone class. It is similar in chemical structure to pefloxacin but differs by containing a methylamino, rather than an ethyl, substituent at the 1-N position. The activity of WIN 49375 in vitro was comparable to those of norfloxacin and pefloxacin against Enterobacteriaceae and generally greater than those of tobramycin and cefotaxime. WIN 49375 was more active in vitro than carbenicillin and mezlocillin against Pseudomonas aeruginosa isolates and showed moderate activity against Staphylococcus aureus, with MICs of less than or equal to 2 micrograms/ml. The in vitro activity of WIN 49375 was not markedly affected by the presence of human serum, the size of the bacterial inoculum, or changes in pH between 6 and 8. Against systemic, gram-negative bacterial infections in mice, WIN 49375 was generally less active than cefotaxime but more active than gentamicin. WIN 49548, the major piperazinyl-N-desmethyl metabolite of WIN 49375, was aa effective as the parent drug against experimental infections in mice when given parenterally. When administered orally, however, this metabolite was less potent than WIN 49375. WIN 49375 was highly active by the oral route, with 50% effective doses within two- to threefold of those obtained with parenteral medication.

Animals↗

Left subclavian artery trauma: in situ vs. rib interspace mobilization for primary anastomosis.

Fifteen autopsy dissections were performed to evaluate the anatomic relationships of the left subclavian artery and primary arterial anastomosis following trauma. The vessel was transected just beyond the origin of the thyrocervical trunk, and the maximal excisable overlapping segment was determined in situ and through the first and second interspaces. By passing the mobilized left axillary artery through the first intercostal space, up to 7.5 cm of a subclavian arterial segment could be resected and primary arterial repair accomplished. The use of the first interspace to gain additional length in primary repair of the left subclavian artery is suggested as an alternative to grafting.

Adult↗

Novel amino-substituted 3-quinolinecarboxylic acid antibacterial agents: synthesis and structure-activity relationships.

A series of novel 3-quinolinecarboxylic acid derivatives have been prepared and their antibacterial activity evaluated. These derivatives are characterized by fluorine attached to the 6-position and substituted amino groups appended to the 1- and 7-positions. Structure-activity relationship studies indicate that antibacterial potency is greatest when the 1-substituent is methylamino and the 7-substituent is either 4-methyl-1-piperazinyl, 16, or 1-piperazinyl, 21. Derivatives 16 and 21, the 1-methylamino analogues of pefloxacin and norfloxacin, respectively, show comparable in vitro and in vivo antibacterial potency to these two known agents. The activity (vs. Escherichia coli Vogel) of 16 (amifloxacin) is the following: in vitro MIC (microgram/mL) = 0.25; in vivo (mice) PD50 (mg/kg) = 1.0 (po), 0.6 (sc).

Anti-Bacterial Agents↗

Middle lobe syndrome.

A review of the major literature dealing with the middle lobe syndrome shows that benign inflammatory disease is the most common etiological factor (62%), with bronchiectasis responsible for at least a quarter of the patients in these series. Early workers indicated that carcinoma rarely originates in the right middle lobe; however, 22% of patients reviewed had malignant tumors as a cause of the syndrome. The original view that bronchial compression was the pathophysiological abnormality leading to development of the syndrome has been rejected by more recent authors. The focus has now turned to the relative isolation of the middle lobe, especially when a complete minor fissure is present. This isolation prevents the aerating effects of collateral ventilation of the upper lobe from reaching the middle lobe and thus impairs the clearing of secretions from the middle lobe bronchus. Bronchoscopy and bronchography are vital in the rational approach to this syndrome. Severe stenosis of the bronchus or tumor can be seen endoscopically in about 40% of patients, and bronchography will demonstrate an anatomical abnormality more than 70% of the time. Both the surgical and the medical approaches to therapy have been endorsed strongly by various authors in the 30 years since the syndrome was described. It now appears that bronchoscopy and, if need be, bronchography should be undertaken to rule out an endobronchial lesion. Timing of these studies will depend on the patient's age, with early examination advocated for the older patient at high risk for lung cancer. If there is reasonable evidence that the process is benign, medical management should be attempted. Lobectomy is performed if malignancy is suspected or if medical therapy fails.

Child, Preschool↗

Antibacterial activities, nephrotoxicity, and ototoxicity of a new aminoglycoside, Win 42122-2.

Win 42122-2 is a new aminoglycoside antibiotic obtained from a mutant strain of Micromonospora purpurea. In vitro and in vivo comparisons of Win 42122-2 with gentamicin and amikacin revealed that Win 42122-2 generally was less active than gentamicin against Pseudomonas and many Enterobacteriacae, especially Klebsiella and indole-negative Proteus. Against most gentamicin-susceptible isolates, Win 42122-2 was more active than amikacin. Gentamicin-resistant clinical isolates were usually resistant to Win 42122-2, although it was active against certain gentamicin-resistant organisms, depending upon the aminoglycoside-modifying enzymes harbored by the organism. However, Win 42122-2 was markedly less toxic than gentamicin in subacute nephrotoxicity studies in rats, ototoxicity experiments in guinea pigs, and ataxia determinations in cats. This series of antibacterial determinations and toxicity evaluations indicated that the reduced toxicity of the antibiotic may be sufficient to provide an improved therapeutic ratio over gentamicin and other aminoglycosides, even though Win 42122-2 is less potent than gentamicin against some bacteria.

Amikacin↗

Liver hernia diagnosed by liver scan and confirmed by angiography.

A right-sided diaphragmatic hernia contining a portion of liver is presented. The diagnosis was made by liver scan and confirmed by selective angiography. The clinical and radiologic findings are discussed. The arteriogram of the herniated liver is the first angiographic demonstration of this entity.

Angiography↗

Active pulmonary hemorrhage localized by selective pulmonary angiography.

Massive hemoptysis in a young woman with negative chest film findings is presented. By using selective pulmonary artery angiography during active pulmonary bleeding, the following findings were demonstrated: (1) intraparenchymal hemorrhage, (2) clearing of blood from the lung and bronchial tree by coughing, (3) early filling of the inferior pulmonary vein. Following lobectomy, specimen angiography suggests the presence of a small arteriovenous fistula. This experience demonstrates that selective pulmonary arteriography may be a useful adjunct in the management of selected patients with massive hemoptysis of obscure etiology.

Adult↗

Pulmonary hyperinflation. A form of barotrauma during mechanical ventilation.

Barotrauma has been used to describe several specific complications related to mechanical ventilation. These include tension lung cyst, pneumothorax, pneumomediastinum, pneumoperitoneum, and subcutaneous emphysema. Pulmonary hyperinflation, another such complication, occurred in 6 patients, being fatal in 3. Two pathophysiologic mechanisms are discussed. The simpler, and well-recognized, ball-valve airway obstruction allows inspiration of air delivered by the mechanical ventilator but prevents expiration. A more complex circumstance exists when pulmonary contusion or infiltration produces differential lung compliances. This allows extreme hyperinflation of areas of normal lung during attempts to ventilate abnormal lung of low compliance. This mechanism is particularly evident when positive end-expiratory pressure (PEEP) is used in an attempt to open collapsed ventilatory units. Functional complications of lung hyperinflation include decreased alveolar ventilation and compression effects on adjacent structures. Interference with and shifts of regional lung perfusion may worsen gas exchange. Proper treatment includes airway clearance by bronchoscopy, the judicious use of bronchodilators, the discontinuance of PEEP, and adjustments of mechanical ventilators to prevent high airway pressures.

Adult↗