Telemedicine: the slow revolution.

The use of interactive video has been recognized as a means of delivering medical support to isolated areas since the 1950s. The Department of Defense recognized early the capacity of telemedicine to deliver medical care and support to front-line military personnel. In 1989, the Texas Telemedicine Project received grants and support from the then American Telephone and Telegraph Company (now AT&T) and the Meadows Foundation of Dallas, Texas, to establish and evaluate telemedicine delivery in central Texas. That project had 6 connected telemedicine sites: 3 in Austin, Texas, and 3 in Giddings, Texas (a small community 55 miles to the southeast of Austin). The sites in Giddings included a chronic outpatient dialysis facility, an inpatient psychiatric hospital, and the emergency department at Giddings Hospital. Patient contact began in April 1991 and continued through March 1993. During that period, data on the 1500 patient contacts made were recorded. After termination of the Texas Telemedicine Project, AT&T continued to provide the transmission lines, and between 1993 and 1996, another 12,000 patient contacts were made. Approximately 80% were dialysis evaluations and 20% were non-dialysis primary care contacts. The original cost of materials and equipment in the Texas Telemedicine Project exceeded $50,000 per site. Today, a secure Internet connection with full-motion video and wireless data transfer to almost any location in the world is achievable with an iPad. Multiple inexpensive applications with connections for electrocardiogram, otoscope, and stethoscope, among others, make this technology extremely inexpensive and user-friendly. The revolution now is rapidly moving forward, with Medicare reimbursing telemedicine contacts in medically underserved areas. Multiple bills are before Congress to expand Medicare and therefore private insurance payment for this service.

The Birth and Development of Continuous Ambulatory Peritoneal Dialysis.

Peritoneal dialysis has a long and tortuous history. First done in animals in the late 1800s, it became clinically practical in the early 1960s. Peritoneal access was first achieved by intermittent abdominal puncture, and then through the development of a 'permanent access' when Silastic became available. The early design is appropriately named for Dr. Henry Tenckhoff. Successful peritoneal dialysis was performed intermittently with infusion of 2 liters of balanced fluid followed by a dwell time of 30-45 min, which in turn was followed by drainage and new infusion. The procedure was used almost exclusively in the intensive care setting but failed to achieve success when applied on a long-term basis. The new concept of extending the dwell time of the dialysis fluid to allow equilibration between an acceptable blood level of urea and the level of urea in the dialysis fluid remarkably reduced the fluid volume required to control uremic toxins and symptoms. This change also allowed the patient to be disconnected from all devices and freely move about as dialysis took place. It was concluded that an acceptable blood level of urea nitrogen was 70 mg %. Equilibration with dialysis fluid, five 2-liter exchanges for 10 liters per day, would allow the removal of 7,000 mg of urea, the average quantity generated on a diet of a 70-kg person eating 1 g of protein per kg of body weight per day. The procedure was originally called 'equilibrium peritoneal dialysis', but was later changed to 'continuous ambulatory peritoneal dialysis'.

Pharmacokinetics of etoricoxib in patients with renal impairment.

The effect of renal insufficiency on the pharmacokinetics of etoricoxib, a selective inhibitor of cyclooxygenase-2, was examined in 23 patients with varying degrees of renal impairment (12 moderate [creatinine clearance between 30 and 50 mL/min/1.73 m2], 5 severe [creatinine clearance below 30 mL/min/1.73 m2], and 6 with end-stage renal disease requiring hemodialysis) following administration of single 120-mg oral doses of etoricoxib. Even the most severe renal impairment was found to have little effect on etoricoxib pharmacokinetics. The low recovery of etoricoxib in dialysate (less than 6% of the dose) supports that hemodialysis also has little effect on etoricoxib pharmacokinetics, and binding of etoricoxib to plasma proteins was generally unaffected by renal disease. Single doses of etoricoxib were generally well tolerated by patients with renal impairment. Based on pharmacokinetic considerations, dosing adjustments are not necessary for patients with any degree of renal impairment. However, because patients with advanced renal disease (creatinine clearance below 30 mL/min/1.73 m2) are likely to be very sensitive to any further compromise of renal function, and there is no long-term clinical experience in these patients, the use of etoricoxib is not recommended in patients with advanced renal disease.

Acute effects of hemodialysis on nitrite and nitrate: potential cardiovascular implications in dialysis patients.

Cardiovascular mortality in dialysis patients remains a serious problem. It is 10 to 20 times higher than in the general population. No molecular mechanism has been proven to explain this increased mortality, although nitric oxide (NO) has been implicated. The objective of our study was to determine the extent of the removal of the NO congeners nitrite and nitrate from plasma and saliva by hemodialysis, as this might disrupt physiological NO bioactivity and help explain the health disparity in dialysis patients. Blood and saliva were collected at baseline from patients on dialysis and blood was collected as it exited the dialysis unit. Blood and saliva were again collected after 4-5h of dialysis. In the 27 patients on dialysis, baseline plasma nitrite and nitrate by HPLC were 0.21±0.03 and 67.25±14.68 µM, respectively. Blood immediately upon exit from the dialysis unit had 57% less nitrite (0.09±0.03 µM; P=0.0008) and 84% less nitrate (11.04 µM; P=0.0003). After 4-5h of dialysis, new steady-state plasma levels of nitrite and nitrate were significantly lower than baseline, 0.09±0.01 µM (P=0.0002) and 16.72±2.27 µM (P=0.001), respectively. Dialysis also resulted in a significant reduction in salivary nitrite (232.58±75.65 to 25.77±10.88 µM; P=0.01) and nitrate (500.36±154.89 to 95.08±24.64 µM; P=0.01). Chronic and persistent depletion of plasma and salivary nitrite and nitrate probably reduces NO bioavailability and may explain in part the increased cardiovascular mortality in the dialysis patient.