High protein intake during continuous hemodiafiltration: impact on amino acids and nitrogen balance.

AIMS: To study the effect of combined continuous veno-venous hemodiafiltration (CVVHDF) and high (2.5 g/kg/day) parenteral amino acid supplementation on nitrogen balance, amino acid losses and azotemic control in a cohort of patients with severe acute renal failure (ARF). METHODS: We administered 2.5 grams/kg/day of amino acids intravenously to seven critically ill patients with ARF. We obtained paired blood and ultrafiltrate (UF) samples (n=20) and calculated amino acid clearances and losses, nitrogen balance, protein catabolic rate and total nitrogen losses. RESULTS: The median total serum amino acid concentration was high at 5.2 mmol/L with particularly high concentrations of ornithine, lysine, and phenylalanine, but a low level of histidine. The median overall amino acid clearance was 18.6 ml/min (range: 12 to 29 ml/min). UF losses as percentage of administered dose were high for tyrosine (53.6%) but low for methionine (3.0%) and arginine (2.3%). A positive nitrogen balance was achieved in 7 (35%) of the 20 study days with an overall median nitrogen balance of -1.8 g/day. Urea levels were maintained at a median of 26.6 mmol/L. CONCLUSIONS: High protein intake increases the serum concentrations of most amino acids. Such protein supplementation, when coupled with CVVHDF achieves a slightly negative overall nitrogen balance in extremely catabolic patients while still allowing adequate azotemic control.

Out of hospital outcome and quality of life in survivors of combined acute multiple organ and renal failure treated with continuous venovenous hemofiltration/hemodiafiltration.

OBJECTIVE: To study the out-of-hospital quality of life and long-term survival of critically ill patients with combined multiple organ failure and acute renal failure treated with continuous renal replacement therapy (CRRT). DESIGN: Study based on responses to postal questionnaire and clinical information obtained during treatment in the intensive care unit (ICU). SETTING: ICUs of two tertiary institutions. PATIENTS: 85 survivors from a pool of 250 patients with combined acute multiple organ and renal failure who were treated with CRRT. METHOD AND RESULTS: Anonymous postal questionnaire based on an activity index, mental function index, and a simplified version of the Nottingham Health Profile. Of the 250 patients, 85 (34%) survived to be discharged from hospital: 57 males (67%) and 28 females (33%), mean age 56.9 years (range 13.4-81). Mean duration of ICU stay was 10.9 days (range 2-52), mean admission Acute Physiology and Chronic Health Evaluation II score was 24.2 (range 15-41), and mean duration of CRRT was 6.2 days (range 1-34). Mean follow-up time was 2.5 years (range 0.1-5.3). Thirty-three of the 85 patients (38.8%) did not reply to the questionnaire; 35 patients (41.7%) were alive at the time of response and 17 (20%) were deceased. Of the 35 responders, 68.5% were satisfied with their present state of health, despite 60.6% stating that their mobility had been affected, with 41.9% being unable to walk more than 200 metres. Most (94.5%) survivors, however, felt that their treatment had been worthwhile, and 91.2% said that they would undergo the same treatment again if necessary. The approximate cost for each year of survival was U.S. $ 50000. CONCLUSIONS: In the majority of patients who survived to be discharged from hospital after combined acute multiple organ and renal failure, the overall state of health and quality of life seemed acceptable. Most patients felt that their treatment was worthwhile and that they would undergo the same treatment again if necessary. Our findings suggest that the cost and effort associated with CRRT and ICU care in these patients are high but broadly comparable to those associated with the care of other serious illnesses. They are also seen as worthwhile by survivors, who consider their life to be of acceptable quality.

Automatic detection of eye movements in REM sleep using the electrooculogram.

An automated method for detecting and counting eye movements using the electrooculogram (EOG) wave form during rapid-eye-movement (REM) sleep is presented. The method is formulated as a sequential decision process with decisions based on slope and amplitude threshold criteria. Signal processing techniques such as digital filtering and smoothing are used to improve the effectiveness of the method. Validation is done by using the method on EOG data from three infants and comparing the automated count of eye movements with the visual counts of human observers. The correlation coefficient between the automated and visual count is greater than 0.9, the first-order regression coefficient close to 1.0, and the zero-order regression coefficient close to 0. We believe that this method will be useful in differentiating between the substates of REM sleep in studies of cardiorespiratory physiology.