Blood pressure control in dialysis patients: importance of the lag phenomenon

Failure by the world dialysis community to understand and use the dry-weight method of blood pressure (BP) control has resulted in an increasing incidence of treatment-resistant hypertension, which remains the principal cause of cardiovascular morbidity and mortality. This failure may in part be because the relationship between the extracellular volume (ECV) and BP is not simple and linear, but complex, because of a lag of several weeks between the normalization of the time-averaged ECV and the decrease in BP. Another cause for this failure may be the unwillingness to taper and stop all antihypertensive medications during the transition from hypertension to normotension. In this report, we describe in detail the lag phenomenon, document its presence during treatment in other populations, and describe how this knowledge is used in the application of the dry-weight method of drug-free BP control in the dialysis population.     

Effect of electrode location in great cardiac vein on the ventricular defibrillation threshold

This study tested the hypothesis that the DFT could be lowered by delivering a weak auxiliary shock in conjunction with a stronger primary shock with the auxiliary shock electrode near the cardiac region where the primary shock electric field is weakest. This hypothesis was tested by determining the DFTs with the auxiliary shock delivered from different locations within the great cardiac vein (GCV). In 15 dogs, catheters with defibrillation electrodes were placed transvenously in the RV apex, the SVC, and the GCV. An active can electrode and the SVC electrodes were electrically coupled to serve as a return electrode for the RV and GCV electrodes. DFTs were determined for a primary shock through the RV electrode with and without a subsequent auxiliary shock of lower amplitude through the GCV electrode. The leading edge voltage and current at DFT were significantly lowered by addition of the auxiliary shock (17% and 19% decreased, respectively), but energy was not changed. The animals were divided into three groups according to the location of the GCV electrode. The leading edge voltage, current, and total delivered energy at the DFT were significantly lower in animals with the GCV electrode near the apex (22%, 24%, and 13% reduction, respectively) compared with those where the GCV electrode was positioned away from apex (8%, 10% reduction and 18% increase, respectively, P < 0.001). Application of an auxiliary shock to the apical region, near the region where previous studies have indicated that the RV primary shock has its weakest effects, caused the greatest decrease in DFT.     

Design and preliminary evaluation of an expert system for platelet request evaluation

In spite of growing awareness of the potential risks associated with transfusion, the number of platelet units transfused in the United States continues to increase each year. There is a growing interest in ensuring that all transfusions are administered for appropriate reasons. Prospective review of requests for transfusions has been used to accomplish this goal. Although successful in reducing the number of inappropriate transfusions, this review method requires great time commitments by blood bank personnel and physicians. A knowledge-based system (ESPRE) that aids hospital blood bank personnel in the review of requests for platelet transfusions has been developed. The system automatically obtains most of the required patient data via a direct link to the hospital's main laboratory computers. The system generates a printed report that includes a list of patient-specific data, a list of the conditions for which a transfusion would be appropriate for the particular patient (given the clinical condition), and the conclusions drawn by the system. During a preliminary clinical evaluation of ESPRE, 73 randomly selected platelet transfusion requests were evaluated for approval by laboratory personnel and ESPRE. Overall, ESPRE would have approved 71 of the requests and laboratory staff would have approved 72. Forty-four percent of the requests would have been approved for the same reasons given by the staff. There were only three disagreements on final approval between ESPRE and blood bank personnel. This computerized expert system is a promising approach to the prospective review of all platelet transfusions.     

Patient-related blood drives

Ten patient-related blood drives were evaluated and compared to five other blood drives. The patient-related blood drives were easier to organize, more fruitful, and more satisfying for the donors and workers. The authors suggest a role for patient-related blood drives in the present recruitment system and discuss how hospitals and blood centers can coordinate their efforts to have this type of blood drive. Finally, it is suggested that patient-related blood drives can increase recruitment, especially in large metropolitan areas that suffer from chronic blood shortages.     

Hepatitis A virus infections associated with clotting factor concentrate in the United States

BACKGROUND: Two cases of hepatitis A among persons exposed to the same lot of solvent/detergent-treated antihemophilic factor VIII concentrate were reported to a surveillance system. An investigation was conducted to find additional cases and determine the source of infection. STUDY DESIGN AND METHODS: A seroprevalence study was conducted among persons with exposure to the suspect lot for serologic evidence of recent infection with hepatitis A virus (HAV). RESULTS: Six cases of recent HAV infection were discovered: four of the patients had been infused with material from the suspect lot of factor VIII, and two had received infusions of factor IX concentrate made from plasma pools common to the suspect factor VIII lot. HAV was identified in one of the plasma pools, in the factor VIII product, and in serum or stool from two factor VIII recipients and one factor IX recipient. The genetics sequence of the virus in the plasma pool, the factor VIII lot, and the factor VIII recipients were identical, while that of the virus in the factor IX recipient differed by a single base. CONCLUSION: These data document the transmission of HAV by a factor VIII concentrate and implicate factor IX products manufactured from a common source-plasma pool.     

Prodromal Herpes Zoster Mimicking Odontalgia - A Diagnostic Challenge

Herpes zoster (shingles) is caused by reactivation of the latent varicella zoster virus which is present due to an earlier varicella infection (chicken-pox). Herpes Zoster is a less common and endemic disease than varicella, although factors causing reactivation are still not well known, but it occurs in older and/or immunocompromised individuals. Involvement of C3, T5, L1, L2 and first division of trigeminal nerve are the most frequently encountered whereas the involvement of second and third division of trigeminal nerve is rarely seen. During the prodromal stage, the only presenting symptom may be odontalgia, which may prove to be a diagnostic challenge for the dentist, since many diseases can cause orofacial pain, and the diagnosis must be properly established before final treatment. Here we present a case of herpes zoster involving the second division of trigeminal nerve masquerading as odontalgia. The difficulties in diagnosis and management are discussed.