Microbial resistance: what is to be done? Information from the panel of experts

This document represents the recommendations of a panel of Spanish experts on antibiotic use and resistance. In a Task Force, under the auspices of the Spanish Ministry of Health and Consumer Affairs that took place in 1994 in Madrid, the members were gravely concerned about the national increase in antibiotic resistance. They analysed the development, evolution and spread of antibiotic resistance among community-acquired human bacterial pathogens in Spain, its relation with antibiotic consumption, and they proposed future surveillance strategies for monitoring the patterns of antibiotic use and consumption. Success will require a collective action among the producers (pharmaceutical industry), prescribers (doctors, veterinarians), dispensers (pharmacists), and consumers (patients). Two similar documents have been recently published by the American Society of Microbiology and the World Health Organization showing the global concern about this topic.     

Cyanosis and multiple pulmonary nodules

Though thyroid hormone abnormalities have been identified in many cardiac conditions, the role of thyroid hormones in congestive heart failure has not been well defined. In a population of patients with advanced heart failure, a reduction in triiodothyronine (T3) with an increase in reverse T3 was identified in many patients, with an abnormally low ratio of T3/reverse T3 being the strongest predictor of mortality. Normalization of thyroid indices appeared to be necessary for prolonged survival to occur. To address the concern of T3 administration possibility exacerbating a hypermetabolic state, basal metabolic rate was measured in a group of advanced heart failure patients and was found to be generally within the normal range. A preliminary safety study of short-term intravenous T3 administration (bolus +/- 6 h infusion, total dose 0.15-2.7 micrograms/kg) was then performed in 23 patients under hemodynamic and electrocardiographic monitoring. There were neither adverse events nor substantial hemodynamic changes, but some patients had an increase in cardiac output, consistent with a peripheral vasodilatory effect. With this foundation, further investigation into the possible role of T3 and its analogs in congestive heart failure therapy may be pursued.     

Neurogenic pulmonary edema in fatal and nonfatal head injuries

Impaired pulmonary function is a frequent but poorly understood complication of acute head injury (HI). A potential early contributor to the pulmonary dysfunction seen in HI patients is neurogenic pulmonary edema (NPE). We hypothesized that NPE would occur early after HI and that it would have a continuum of clinical severity depending on the severity of the HI and associated intracranial hypertension. A large autopsy data base and inpatient HI data base were used to search for cases of NPE. Patients in the autopsy data base were stratified according to injury type and whether they died at the scene or within 96 hours of injury. There were significant (p < 0.0001, analysis of variance) elevations in lung weights in patients dying at the scene and within 96 hours from HI, compared with those dying from other noncentral nervous system injuries. No other organs studied showed significant weight increases. The incidence of NPE in isolated HI patients dying at the scene was 32%. In patients with isolated HI dying within 96 hours, the incidence of NPE was 50%. We found an inverse correlation (r = 0.62; p < 0.0014) between the initial cerebral perfusion pressure and the PaO2/FIO2 ratio despite a normal-appearing chest x-ray film. We conclude that NPE occurs frequently in HI patients. The process of edema formation begins early in the clinical course and is isolated to the lung.(ABSTRACT TRUNCATED AT 250 WORDS)     

Alveolar rhabdomyosarcoma involving the heart. An echocardiographic, angiographic and pathologic study

A 12-year-old girl, who had had an above-knee amputation of the left leg for a soft tissue sarcoma six years prior to this admission, presented with syncope, angina, and signs of aortic stenosis. Echocardiography demonstrated a mass arising from the interventricular septum with obstruction of the left ventricular outflow tract and aortic valve. Cardiac catheterization and angiography confirmed these findings. At operation, a tumor was found involving the interventricular septum. Histologically, it was an alveolar rhabdomyosarcoma, and it appeared similar to the previous tumor. The patient was treated by partial surgical resection, cytotoxic drugs and localized radiation therapy and has been followed by serial echocardiography.     

Primary retinal degeneration: evidence of normal phagocytosis in the retinal pigment epithelium

In rats with primary retinal degeneration, lens extraction combined with total retinal detachment provided a model for injection of a tracer of colloidal carbon into the subretinal space. Electron microscopy and acid phosphatase cytochemistry were subsequently used to analyze the ingestion of tracer by the retinal pigment epithelium. It was found that the attachment, ingestion, and digestion phases of the phagocytic process were apparently preserved. From this evidence it is suggested that there is no lack of phagocytic power in the retinal pigment epithelium of affected rat strains.     

Forestomach acidosis in six New World camelids

Forestomach acidosis was diagnosed in 2 llamas and 4 alpacas. All were young, group-housed, sexually intact males. Clinical signs included forestomach atony, lethargy, ataxia, diarrhea, and tachycardia. Forestomach distention was observed in only 1 llama. Clinicopathologic abnormalities included low forestomach fluid pH, hyperchloremia, hypokalemia, and metabolic acidosis. Although camelids differ from domestic ruminants in typical management practices and behavioral, anatomic, and physiologic characteristics, they are, nonetheless, susceptible to forestomach acidosis. Gastric fluid analysis was essential for an accurate diagnosis. Four of 6 camelids recovered after PO and IV treatment with alkalinizing agents and fluids, antibiotics, and thiamine.     

Intraclass correlation estimates in a school-based smoking prevention study. Outcome and mediating variables, by sex and ethnicity

Most school-based smoking prevention studies employ designs in which schools or classrooms are assigned to different treatment conditions while observations are made on individual students. This design requires that the treatment effect be assessed against the between-school variance. However, the between-school variance is usually larger than the variance that would be obtained if students were individually randomized to different conditions. Consequently, the power of the test for a treatment effect is reduced, and it becomes difficult to detect important treatment effects. To assess the potential loss of power or to calculate appropriate sample sizes, investigators need good estimates of the intraclass correlations for the variables of interest. The authors calculated intraclass correlations for some common outcome variables in a school-based smoking prevention study, using a three-level model-i.e., students nested within classrooms and classrooms nested within schools. The authors present the intraclass correlation estimates for the entire data set, as well as separately by sex and ethnicity. They also illustrate the use of these estimates in the planning of future studies.     

Platelet and neutrophil distributions in pump oxygenator circuits. III. Influence of nitric oxide gas infusion

The authors used quantitative gamma scintigraphy to evaluate the influence of nitric oxide gas on platelet and neutrophil deposition in Cobe Duo microporous oxygenators during cardiopulmonary bypass (CPB). The effects of nitric oxide gas on circulating platelet and neutrophil counts and platelet function also were assessed. Animals were prepared by standard methods. Cells were harvested, labeled (111 In platelet and 99mTc neutrophil), infused, and recirculated. Nitric oxide gas, a guanylate cyclase pathway promoter, was infused int he Duo gas port at 500 ppm (t = 0-60 min), increased to 1,000 (t = 60-80 min), and stopped (final, 10 min). Images were taken at 10-15 min intervals during CPB. Standard isotope image corrections were made. No differences between nitric oxide gas and control experiments were observed for flow, pressure, hematocrit, or replacement volume. Nitric oxide gas infusion significantly (p < 0.05) reduced both platelet adherence to the oxygenator and in vitro platelet aggregation. Neutrophil adhesion tended to be lower, and circulating platelet and neutrophil counts tended to be higher with nitric oxide gas infusion. Results of in vitro aggregometry studies using rabbit platelets indicate that the class V phosphodiesterase inhibitor zaprinast can strongly enhance the inhibitory effects of nitric oxide. The authors conclude nitric oxide gas is a promising platelet sparing agent in the setting of CPB.     

Complications resulting from saphenous vein patch graft after carotid endarterectomy

OBJECTIVE: Reducing surgical risks to the minimum in carotid endarterectomy has become crucial, especially with the results of recent clinical trials extending indications to asymptomatic patients. The use of the saphenous vein patch graft (SVPG) has been suggested to reduce early postoperative thrombosis and cerebral infarct as well as late recurrent stenosis. However, the exact risks and complications involved in this technique are not known. METHODS: During a 23-year period (1972-1994), 2888 carotid endarterectomies with SVPG for primary carotid stenosis were performed by the Neurosurgical Cerebrovascular Service at the Mayo Clinic. The data from all patients were retrospectively analyzed, emphasizing postoperative complications related to SVPG. RESULTS: There were five postoperative vein ruptures (0.17%), four cases of aneurysm formation, and three cases of deep infection necessitating surgical intervention. The vein patch ruptured in one male patient and four female patients (mean age, 69 yr). All ruptures occurred within 4 days of the primary operation, including two during the first 24 hours. All patients with rupture underwent emergency surgery and were found to have intact suture lines and tears in the middle of the grafts. Two patients recovered without deficits, one suffered major disability, and the other two died. Aneurysm of the patch developed in two male patients and two female patients (mean age, 71 yr). All of the patients developed painless pulsatile neck masses 1 to 9 years after the initial surgery; two also had recurrent ischemic symptoms. All of the patients with aneurysms underwent surgical correction without consequences. CONCLUSION: Although the benefit of routine use of SVPG in carotid endarterectomy is still the focus of debate, this analysis showed that its use adds a small but definite risk of serious complications related to inherent weakness of the venous tissue. If a surgeon chooses to use a patch graft, our recommendation is for use of a synthetic material rather than vein.