Phonatory effects of body fluid removal.

Adequate body and vocal fold hydration are believed to be critical to phonation. We hypothesized that body fluid reduction, without dehydration, would increase phonation threshold pressure (P(th)) and be associated with patient-perceived increases in phonatory effort and worsening voice quality. Using a single-subject, full-reversal design, a controlled volume of body fluid was repeatedly removed via ultrafiltration from adults with end stage renal disease (2 women, 4 men, ages 40-85 yrs). Two additional men (ages 81 and 68 yrs) served as placebo and healthy true controls, respectively. P(th), vocal effort and quality, blood pressure, and heart rate were assessed longitudinally. P(th) increased significantly with fluid volume reduction (3-4% of body weight from a hypervolemic to a grossly normovolemic body state) and reversed to baseline with fluid replacement in 4 of 6 treated subjects. Effects were observed with net ultrafiltration rates greater than or equal to 1.0 L/h; these effects were not observed in control subjects. Fluid loss accounted for 31.6% of variance in P(th) and 40.0% of variance in perceived vocal effort. Heart rate, systolic blood pressure, and/or diastolic blood pressure were significantly correlated with P(th) or fluid volume reduction in 6 subjects, including the placebo control (-.70 < or = r < or = -.44). Results indicate that substantial extracellular volume depletion without body dehydration causes voice symptoms, an effect possibly mediated by autonomic nervous control. We propose that mechanisms intrinsic to the vocal fold regulate its water flux and respond to hydration challenges.

Palliative care/hospice and the withdrawal of dialysis.

While the majority of end-stage renal disease (ESRD) patients on dialysis lead satisfying lives, an increasing number are choosing to withdraw from dialysis before death. A partnership between nephrology and palliative care/hospice healthcare teams would seem likely in the care of ESRD patients, yet this is often not the case. In anticipation of increasing participation by palliative care/hospice teams in the care of such patients, this article reviews the decision-making process of withdrawal and the medical care of the patient who withdraws. While withdrawal can be an acceptable choice from a medical, legal, psychiatric, and ethical point of view, it can nonetheless be complex. Profound decisions are often characterized by the need for time to process, and by ambivalence among patient, family and healthcare providers. In addition to caring for the patient and family, the palliative care/hospice team will want to consider the needs of the referring nephrology team as well. A "uremic death" is characterized as painless; however, other symptoms related to the accumulation of toxins and fluid can be anticipated and managed. Pharmacological intervention of uremic symptoms, as well as the pain attendant to other, nonrenal comorbid disease is accomplished with awareness of the impact of renal failure on the excretion of various drugs and their metabolites.

High anion gap metabolic acidosis associated with aminocaproic acid.

OBJECTIVE: To report a case of high anion gap metabolic acidosis related to infusion of aminocaproic acid (ACA) that temporarily corrected during hemodialysis and resolved upon ACA discontinuation. CASE SUMMARY: A 65-year-old white woman with staphylococcal sepsis complicated by acute renal failure was treated with ACA to control a hemorrhagic coagulopathy. After receiving an initial 5-g bolus of ACA, she received a continuous intravenous infusion of 500 mg/h for just over 5 days, then 250 mg/h for a final 12 hours. Immediately after beginning ACA therapy, she developed a severe anion gap metabolic acidosis that briefly improved after hemodialysis. The condition resolved completely only after the discontinuation of ACA and therapy with a systemic alkalinizer. DISCUSSION: ACA is not among the previously identified causes of high anion gap metabolic acidosis. The temporal profile relating anion gap to ACA initiation, hemodialysis treatment, and ACA discontinuation supports causality in this case. The magnitude of increase in the anion gap appears to have been proportional to the dose of ACA. CONCLUSIONS: In patients with renal impairment, ACA administration may produce a dose-related, high anion gap metabolic acidosis that might be reversible during hemodialysis. Insufficient data are available, but when ACA must be used in such patients, a more conservative dosing of ACA should be coupled with close monitoring.

Ambulatory blood pressure and Holter monitoring of emergency physicians before, during, and after a night shift.

BACKGROUND: Occupational stress may affect measured hemodynamic and electrocardiographic variables. Data describing the physiologic effects of work on the emergency physician (EP) are sparse. OBJECTIVE: To determine whether blood pressure (BP) and heart rate variability (HRV) of the EP are affected during a night shift in the ED. METHODS: This prospective study evaluated BP and HRV in attending EPs at an urban academic medical center for a 24-hour period during which a night shift was scheduled. Participants were fitted with an oscillometric ambulatory BP device and a Holter monitor at 1500 hours on the day of a night shift. The monitors were worn continuously before, during, and after a night shift (2300-0700) in the ED and were removed at 1500. Systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), heart rate (HR), measures of HRV, and occurrence of cardiac dysrhythmias were evaluated. Comparisons were made for ED and non-ED awake periods and non-ED sleep periods. RESULTS: Twelve participants completed the study. Eight (67%) subjects were men and 4 (33%) were women. Age ranged from 28 to 40 years (mean 34.1+/-4.1). Results were analyzed using repeated-measures ANOVA. An elevation of mean DBP (5.5 mm Hg+/-4.37; p < 0.05; 95% CI 1-10) during night shift activity was seen. A trend toward elevation of SBP, MAP, and HR was discernible. HRV measures indicated a significant relative increase in sympathetic vs parasympathetic tone and an increase in HR of prework and work compared with postwork. Dysrhythmias observed included sinus tachycardia, sinus bradycardia, sinus pause, atrial premature beats, atrial couplets and triplets, supraventricular tachycardia, and premature ventricular contractions. CONCLUSIONS: The elevation of DBP during a night shift suggests that these patterns of BP variability are activity- or stress-related rather than a result of a true diurnal variation. HRV analysis suggests that sympathetic tone is heightened both before work and during work. The implications of such findings to the health of the EP warrant further investigation.

Reversibility of long-standing urinary tract obstruction requiring long-term dialysis.

Urinary tract obstruction of longer than 4 to 6 weeks' duration is usually said to be irreversible. Older reports of unilateral obstruction have documented return of kidney function after longer periods of obstruction. The duration of bilateral obstruction compatible with return of life-sustaining renal function is poorly defined. We report herein three cases of long-standing urinary tract obstruction leading to apparent dialysis-dependent end-stage renal disease, where relief of obstruction eventually led to discontinuation of dialysis.

A comparison of cutaneous testing and ELISA testing for assessing reactivity to ethylene oxide-human serum albumin in hemodialysis patients with anaphylactic reactions.

In five patients who have experienced anaphylaxis and in 29 patients who have not had such episodes during hemodialysis, we have performed two immunologic studies: cutaneous testing with ethylene oxide-human serum albumin (ETO-HSA) and ELISA for IgE against ETO-HSA. Four of five patients with reactions had positive cutaneous tests, whereas only one nonreactor had a positive skin test (p less than 0.0002). The same four of five patients with reactions also had positive ELISA results, whereas three nonreactors has positive ELISA results (p less than 0.003). In this group of patients, the positive predictive value of cutaneous testing (80%) is somewhat higher than that of ELISA testing (57%). However, the sensitivity, specificity, and negative predictive values are similar. We conclude that cutaneous testing with ETO-HSA probably offers a small advantage over IgE against ETO-HSA as determined by ELISA.

Aging and renal function.

Reflection on the circumstances of the elderly permits one to understand the risk factors for renal disease that are present in that population; to consider what impact impairment of the primary functional capacities of the kidney will have; to structure a diagnostic work-up; and finally, to close the loop by modifying care in order to protect the elderly from renal insufficiency.

Failure of deferoxamine to improve iron overload in chronic hemodialysis patients.

We prospectively studied the in vivo dialytic clearance of iron after deferoxamine (DFO) administration in four stable iron-overloaded chronic hemodialysis patients by quantifying iron concentration in blood entering and leaving the dialyzer and in dialysate after infusions of DFO. No significant arteriovenous iron differences were demonstrated. The mean ratio of venous to arterial iron approached identity at 1.005. All dialysate concentrates used contained large amounts of iron (300-610 micrograms/dl). No changes in efferent versus afferent dialysate iron concentration could be demonstrated. We conclude (a) iron removal during dialysis with DFO was not demonstrated; (b) the dialysate concentrate tested contained large amounts of iron; (c) in view of potentially significant toxicity, and lack of demonstrable therapeutic benefit, caution in prescribing DFO chelation therapy for iron overload is recommended.

Parathyromatosis in hyperparathyroidism.

Recurrent hyperparathyroidism after parathyroidectomy may present a difficult diagnostic problem. A rare etiology is parathyromatosis (multiple nodules of hyperfunctioning parathyroid tissue scattered through the neck and mediastinum) due to spillage of otherwise benign parathyroid tissue during surgery. We present a case of recurrent hyperparathyroidism and parathyromatosis due to tissue spillage during surgical removal of probable double adenomas, a rare cause of primary hyperparathyroidism. Thus, parathyromatosis must be included in the differential diagnosis of recurrent or persistent hyperparathyroidism, distinguished from parathyroid carcinoma by histologic criteria. The surgeon must be careful of parathyroid spillage during surgery, even of benign tumors of the parathyroids.

Phosphate-binding effects of sucralfate in patients with chronic renal failure.

Sucralfate has been reported to reduce serum phosphate concentration in patients with chronic renal failure. To evaluate whether sucralfate could be used to treat hyperphosphatemia secondary to chronic renal failure and whether this treatment resulted in a reduced exposure to aluminum, an open-label crossover study was designed to determine the efficacy, relative potency, safety, and cost of sucralfate v aluminum hydroxide. Of the 21 hemodialysis patients completing both phases of the crossover study, serum phosphate could be maintained below 4.5 mg/dL (1.45 mmol/L) in 16 with sucralfate and in 14 with aluminum hydroxide. The 16 patients controlled on sucralfate consumed 1,694 +/- 190 mg/d of aluminum to maintain a serum phosphate concentration of 3.91 +/- 0.17 mg/dL (1.27 +/- 0.05 mmol/L) compared with the 14 patients controlled on aluminum hydroxide with an aluminum intake of 2,678 +/- 294 mg/d (P less than 0.025) and a serum phosphate concentration of 3.94 +/- 0.13 mg/dL (1.27 +/- 0.04 mmol/L). Thus sucralfate was an effective, albeit expensive, alternative to aluminum hydroxide for the treatment of hyperphosphatemia associated with chronic renal failure. Although the difference in aluminum intake was significant, use of sucralfate did not result in lower serum aluminum concentrations.

Acidotic alterations in oxidative metabolism influencing rat renal slice ammoniagenesis.

We believe that two findings are interconnected and help to comprehend a major mechanism behind the regulation of renal ammonia production during acidosis. First, slices from acidotic compared to control and alkalotic rats produce more ammonia from glutamine. Second, inhibition of renal oxidative metabolism at various points by metabolic inhibitors augments slice ammoniagenesis. Based on this, our purpose was to determine whether enhanced renal ammoniagenesis during acidosis could occur through the same mechanism as the metabolic inhibitors. However, metabolic inhibitors (malonate; arsenite; 2,4-dinitrophenol) usually decrease while acidosis increases slice gluconeogenesis. There is one known exception. Fluorocitrate, which blocks citrate metabolism, simulates the acidotic condition by enhancing both ammonia and glucose production. Accordingly, a block of oxidative metabolism if located prior to citrate oxidation in the tricarboxylic acid cycle could theoretically augment ammoniagenesis during acidosis. Lactate, is a major renal fuel whose oxidative metabolism would be blocked by fluorocitrate. There, we concentrated on the effects of acidosis on lactate as well as glutamine metabolism. Lactate decarboxylation decreases in the face of increased glucose production during acidosis, and lactate inhibition of glutamine decarboxylation decreases in slices from acidotic rats. Also, we found lesser oxygen consumption in the presence of lactate by kidney slices from acidotic rats compared to control and alkalotic rats. We postulate that relatively less incorporation of lactate into the TCA cycle, causing decreased citrate formation and citrate oxidation during acidosis, contributes, at least in part, to acidotic adaptation of ammoniagenesis.

Reagent strip glucose monitoring methods in chronic hemodialysis.

Reagent strip blood glucose testing methods have not been extensively validated in dialysis patients, a serious omission as thousands of diabetic patients are now entering dialysis. Severe anemia and uremia are potentially confounding variables that might impair those testing methods. Various methods were tested pre- and postdialysis, and compared with standard laboratory results. In general, strip methods (SM) underestimated laboratory results by approximately 15%. Extremes of blood urea nitrogen, hematocrit, or blood glucose levels did not affect this reliability. Such methods appear to be suitable for use in chronic hemodialysis patients.

Severe anaphylactoid reactions to cuprammonium cellulose hemodialyzers.

Twenty-one severe reactions to hemodialysis occurred in approximately 260,000 dialysis treatments at three centers within a 10 1/2-year period. Reactions typically appeared within minutes of initiating dialysis, and were characterized by cardiopulmonary, mucocutaneous, and/or gastrointestinal tract symptoms highly suggestive of anaphylaxis. Four respiratory arrests and one death resulted. Analysis of dialyzer use patterns and of each patient's dialyzer exposure history strongly implicated hollow-fiber dialyzers made of cuprammonium cellulose (CC) as a cause of these reactions. No obvious factors could be found to identify predisposed patients. Less than optimal rinsing of the CC hollow-fiber dialyzers prior to use may have been responsible for some, but not all, of these reactions.