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N Boyce

Publications and source records attributed to N Boyce.

At least 55 records · Page 3Linked to original sources
PubMed1994

A prospective study of continuous hemodiafiltration in the management of severe acute renal failure in critically ill surgical patients.

Severe acute renal failure associated with surgical disease and a highly catabolic state poses a major therapeutic challenge. Treatment by conventional dialysis or arteriovenous hemofiltration suffers from serious shortcomings. The current study assesses the clinical and biochemical impact of a newer approach (continuous hemodiafiltration) in a cohort of 60 critically ill surgical patients with severe renal failure. All patients were studied prospectively and assessed for illness severity. Their biochemical response to therapy was analyzed and their clinical course to either death or hospital discharge documented. The use of continuous hemodiafiltration (CHD) permitted full control of azotemia in all patients (mean steady-state urea concentration: 19.8 mmol/L) and was associated with rapid control of acidemia (mean pretreatment pH: 7.27; mean ph after 24-h treatment: 7.35; p < .001). During the 15,696 h of therapy, there were no treatment-induced episodes of hypotension and/or hypoxemia. All patients were able to receive full-dose enteral (9) or parenteral (51) nutritional support with 1.5 to 2.5 g/kg/day of protein as tolerated. Despite their illness severity (mean APACHE II score: 28.9) and the need for vasopressor support and ventilation in 90% of cases, 21 patients (35%) survived to hospital discharge. We conclude that continuous hemodiafiltration is safe and effective in surgical critically ill patients with acute renal failure, and that it is associated with a low morbidity and an encouraging survival rate.

APACHE↗
PubMed1994

The outcome of critically ill elderly patients with severe acute renal failure treated by continuous hemodiafiltration.

OBJECTIVES: To study the outcome of critically ill elderly patients with severe acute renal failure managed by continuous hemodiafiltration. DESIGN: Prospective study. SETTING: Intensive Care Unit of tertiary institution PATIENTS: Seventy-two consecutive critically ill patients of 65 years or older admitted to the ICU with severe acute renal failure. Seventy similar control patients of age < 65 years. INTERVENTION: Treatment of all patients with continuous hemodiafiltration. MEASUREMENTS AND MAIN RESULTS: Safety and effectiveness of therapy were assessed. Main outcome measures were duration of oliguria, of ICU stay, and hospital stay for survivors, and survival to ICU discharge and to hospital discharge. Mean APACHE II score on admission was 29.8 (95% confidence interval: 28.5 to 31.1) and mean organ failure score prior to initiation of continuous hemodiafiltration was 3.9 (95% confidence interval: 3.6 to 4.2). Sepsis was present in 51 cases (70.8%) and bacteremia or fungemia in 24 (33.3%). Fifty-three (73.6%) required mechanical ventilation for > 3 days. Vasopressor drugs were used in 65 (90.2%). Continuous hemodiafiltration controlled azotemia in all patients and was only associated with minor complications. Thirty-four patients (47.2%) survived to ICU discharge and 30 (41.6%) to hospital discharge. Among survivors, duration of oliguria was 11.6 days (95% confidence interval: 9.1 to 14.1), mean duration of ICU stay 8.6 days (95% confidence interval: 6.1 to 11.) and mean duration of hospital stay 33.1 days (95% confidence interval: 28.8 to 37.4). No statistically significant difference in survival was found when these patients were compared to a control group of similar but younger patients who also received ICU care and continuous hemodiafiltration for the treatment of severe acute renal failure. CONCLUSIONS: A greater than 40% survival was achieved in critically ill elderly patients with severe acute renal failure by the use of continuous hemodiafiltration. These patients had an in hospital survival comparable to that of younger patients. These findings support an aggressive renal replacement approach in such patients and suggest that continuous hemodiafiltration may be ideally suited to their management.

Acute Kidney Injury↗
PubMed1993

Anticoagulant regimens in acute continuous hemodiafiltration: a comparative study.

OBJECTIVE: To compare and contrast different heparin regimens for extracorporeal circuit anticoagulation in patients receiving acute continuous hemodiafiltration (ACHD). DESIGN: Prospective controlled randomized comparisons of the following regimens: 1) Low dose (500 IU/h) pre-filter heparin versus regional anticoagulation in patients on continuous arteriovenous hemodiafiltration (CAVHD) via A-V shunt. 2) Low dose pre-filter heparin versus no anticoagulation in patients receiving CAVHD via femoral cannulae. 3) Low dose pre-filter heparin versus regional anticoagulation in patients on continuous veno-venous hemodiafiltration (CVVHD). 4) An assessment of the consequences of the use of no anticoagulant in patients predicted to be at high risk of hemorrhagic complications on treatment with CVVHD. SETTING: University Teaching Hospital ICU. PATIENTS: 64 ICU patients with acute renal failure. MEASUREMENTS AND MAIN RESULTS: Haemofilter survival during shunt CAVHD was significantly prolonged by the use of regional anticoagulation compared to the use of low dose heparin (mean filter survival: 57.1 h versus 42.9 h; p < 0.05). In CAVHD using femoral cannulae, no significant differences in haemofilter survival were found between anticoagulation with low dose heparin and the use of no anticoagulant (mean filter survival: 55 h versus 52.5 h; NS). During CVVHD, regional anticoagulation compared to low dose heparin produced a trend towards prolonged filter life which was, however, not statistically significant (mean filter survival: 40.5 h versus 31.4 h; NS). In patients assessed to be at high risk of bleeding, CVVHD without anticoagulation provided a mean filter survival of 40.9 h (95% CI 27-54.8 h). CONCLUSIONS: Regional anticoagulation leads to longer filter survival than low dose heparin in shunt CAVHD. A regimen of no anticoagulation during femoral CAVHD leads to a filter life similar to that of low dose heparinization. During CVVHD, regional anticoagulation and low dose heparin are associated with similar filter survival times. In patients assessed to be at high risk of bleeding, treatment with CVVHD without anticoagulation results in adequate filter survival.

Acute Kidney Injury↗
PubMed1993

Acute renal failure in the critically ill: management by continuous veno-venous hemodiafiltration.

The consequences of newer techniques of continuous renal replacement therapy in critically ill patients are not yet fully known. The clinical and biochemical impact of continuous veno-venous hemodiafiltration (CVVHD) was, therefore, prospectively studied in 60 critically ill patients with acute renal failure. Prospective clinical, biochemical, and hematological data were collected from patients receiving CVVHD. Over the initial 24 hours of therapy, CVVHD resulted in a decrease in mean plasma urea from 34.5 mmol/L (95% confidence interval [CI], 29.4 to 39.6) to 25 mmol/L (95% CI, 21.8 to 28.2). With continued CVVHD, the mean plasma urea reached a plateau level of 17.6 mmol/L (95% CI, 15.8 to 19.4) at 72 hours. This degree of azotemia control was achieved with ease and essentially without complications during 8,360 hours of therapy despite the presence of multi-organ failure and the aggressive administration of protein nitrogen (0.25 to 0.35 g/kg/day). No abnormalities of serum electrolytes developed during treatment. Survival to intensive care discharge was 46.6% and to hospital discharge 41.6%, despite a mean Acute Physiology and Chronic Health Evaluation (APACHE) II score at presentation of 27.7. Continuous veno-venous hemodiafiltration offers superior azotemia control and a safe approach to renal replacement therapy in critically ill patients. Its use is associated with a comparatively favorable outcome. CVVHD may be regarded as the treatment of choice in such patients.

Acute Kidney Injury↗
PubMed1993

A prospective comparative study of continuous arteriovenous hemodiafiltration and continuous venovenous hemodiafiltration in critically ill patients.

We have prospectively studied and compared two consecutive groups of critically ill patients treated with either continuous arteriovenous hemodiafiltration (CAVHD) (n = 28) or continuous venovenous hemodiafiltration (CVVHD) (n = 25) to establish the technique of choice. The two groups were comparable in mean age (59 v 58 years), mean Acute Physiology and Chronic Health Evaluation (APACHE) II score (29.6 v 27.4, P = NS), requirements for inotropic drugs, and mean number of failing organs (2.9 v 3.2). CVVHD led to a greater amount of hourly ultrafiltrate (mean, 590 v 424 mL; P < 0.001), but urea and creatinine clearances were not significantly different with the two techniques. Twelve patients survived in the CAVHD group (42.8%) and 13 in the CVVHD group (52%; P = NS). The major advantage for CVVHD use was the substantial decrease in the number of access-related complications (2 v 10; P < 0.025). We conclude that while CVVHD does not offer a significant increase in solute clearance, it significantly minimizes vascular access-related morbidity and should therefore be regarded as the therapeutic modality of choice.

Chi-Square Distribution↗
PubMed1993

Acute continuous hemodiafiltration: a prospective study of 110 patients and a review of the literature.

One hundred ten critically ill patients with acute renal failure receiving acute continuous hemodiafiltration (ACHD) in our intensive care unit were studied prospectively. Acute continuous hemodiafiltration consisted either of continuous arteriovenous hemodiafiltration or of continuous veno-venous hemodiafiltration, and was used for 17,817 hours (mean duration of patient treatment, 161.9 hours), resulting in a fall from a mean pre-ACHD urea of 35.7 mmol/L to a plateau value of 16.8 mmol/L at 72 hours of treatment. The mean urea clearance achieved was 24.9 mL/min. Eighty of these patients (72.7%) were receiving artificial ventilation at the time of ACHD and 45 (40.9%) had more than four failing organs. The mean APACHE II score was 27.7. Despite the degree of illness severity, 42 patients (32.2%) survived to discharge from hospital. The use of ACHD was associated with hemodynamic stability, rapid normalization of electrolytes, and the ability to freely administer drugs, blood, and/or blood products. It also allowed for maintenance of an aggressive, nitrogen-rich, nutritional regimen. Support of these critically ill patients with acute renal failure using ACHD was achieved safely and without the employment of additional dialysis-trained nursing staff. Our own experience and a review of the available literature strongly suggest that the advantages associated with the use of ACHD therapies are clinically significant and support the view that ACHD is a modality of renal replacement most suited to critically ill patients with acute renal failure.

Acute Kidney Injury↗
PubMed1993

Continuous veno-venous hemofiltration with dialysis removes cytokines from the circulation of septic patients.

OBJECTIVE: To determine whether continuous veno-venous hemofiltration with dialysis leads to extraction of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) from the circulation of critically ill patients with sepsis and acute renal failure and to quantitate the clearance and removal rates of these cytokines and their effect on serum cytokine concentrations. DESIGN: Prospective, controlled study of TNF-alpha IL-1 beta extraction by continuous veno-venous hemofiltration with dialysis in patients with septic acute renal failure. SETTING: Intensive care unit of a tertiary institution. PATIENTS: Eighteen critically ill patients with sepsis and acute renal failure. Control group of six patients experiencing an acute illness while undergoing chronic hemodialysis. INTERVENTIONS: Collection of blood samples before continuous veno-venous hemofiltration with hemodialysis. Simultaneous collection of prefilter blood and ultradiafiltrate after 4 and 24 hrs of treatment. MEASUREMENTS AND MAIN RESULTS: TNF-alpha and IL-1 beta concentrations were measured in blood and ultradiafiltrate. Their clearances and daily extraction were calculated and compared with a control group. TNF-alpha was detected in 66.6% of serum samples of patients with septic acute renal failure; IL-1 beta was detected in 55% of patients' sera samples. Both TNF-alpha and IL-1 beta were cleared by the hemofilter during continuous veno-venous hemofiltration with dialysis. The mean clearance for TNF-alpha was 30.7 L/day (95% confidence interval 22.4 to 39) with a daily mean excretion of 14.1 micrograms (95% confidence interval 1.7 to 26.5). Mean IL-1 beta clearance was 36.1 L/day (95% confidence interval 25.4 to 46.8) equivalent to a mean daily IL-1 beta excretion of 1 microgram (95% confidence interval 0.9 to 1.1). No measurable concentrations of TNF-alpha or IL-1 beta were found in the serum or ultrafiltrate specimens of control patients. CONCLUSIONS: These findings demonstrate that continuous veno-venous hemofiltration with dialysis can remove both TNF-alpha and IL-1 beta from the circulation of septic, critically ill patients. This cytokine extraction may prove to be of benefit in attenuating the progression of multiple organ dysfunction in patients with sepsis-associated renal failure, who are receiving continuous veno-venous hemofiltration with dialysis. This potential benefit of existing hemofiltration therapies supports their preferential implementation in patients with renal failure associated with severe sepsis. These observations may stimulate the modification of filtration membrane design seeking to specifically augment the clearance from the circulation of a variety of such cytokines.

Acute Kidney Injury↗
PubMed1993

A comparison of conventional dialytic therapy and acute continuous hemodiafiltration in the management of acute renal failure in the critically ill.

OBJECTIVE: To compare and contrast the clinical outcomes in critically ill patients with acute renal failure managed with either acute continuous hemodiafiltration or conventional dialytic therapies. DESIGN: Retrospective review of the medical records of 167 consecutive cases of acute renal failure treated at a single center (July 1982-July 1991). Scoring for illness severity (APACHE II, number of failing organs) and assessment of outcome in terms of biochemical control of azotemia, ARF therapy-related morbidity, and overall morbidity and mortality. SETTING: Tertiary institution. PATIENTS: 167 consecutive critically ill patients with multiorgan failure and acute renal failure. MEASUREMENTS AND MAIN RESULTS: 84 patients received conventional dialytic therapy (CDT) (1982-1988) and 83 acute continuous hemodiafiltration (ACHD) (1988-1991). The etiology of ARF and illness severity indices were similar in both groups (organ failure scores: CDT 3.9 vs. ACHD 4.1; NS). All patients were critically ill, with more severely ill patients within the ACHD groups (mean APACHE II score: CDT 25.8 vs. ACHD 28.1; p < .01). There were no significant differences in pretreatment serum creatinine, glucose, bicarbonate and phosphate, white cell and platelet counts, incidence of disseminated intravascular coagulation, prevalence of sepsis, or evidence of pulmonary and/or peripheral edema. Overall survival was 29.8% for the CDT groups and 41% for the ACHD group (NS). When patients were stratified by severity of illness, survival in those with 2 to 4 failing organs was significantly greater in the ACHD group (CDT 31.1% vs. ACHD 53.8%; p < .025). Similarly, overall survival in patients with intermediate APACHE II scores (24 to 29) was significantly better in those treated with ACHD (CDT 12.5% vs. ACHD 46.4%; p < .025). During the course of ARF, in comparison to CDT, ACHD was associated with greater overall reductions in serum creatinine, and in phosphate and plasma urea, and an increased net nutritional intake. CONCLUSIONS: ACHD provided biochemical and outcome indicator advantages over conventional dialytic therapy. In patients with 2 to 4 failing organs or an intermediate APACHE II score (24 to 29) a significant survival advantage was demonstrated for ACHD over CDT. Although this study is a retrospective analysis, with all the inherent limitations of such studies, it suggests that ACHD is the treatment of choice for ARF in the critically ill, with maximum benefits seen in those with 2 to 4 failing organs and/or intermediate APACHE II scores.

Acute Kidney Injury↗
PubMed1993

Change and opportunity in ambulatory care.

Non-inpatient care is assuming greater importance within the Australian health system. The management of the delivery of health services is becoming a responsibility of clinicians. Clinicians, nurses, managers and academics need to come together to advance these issues. This paper outlines the thinking at Monash Medical Centre, a new 747-bed tertiary hospital situated in the south-eastern suburbs of Melbourne.

Continuity of Patient Care↗
PubMed1992

Use of continuous haemodiafiltration: an approach to the management of acute renal failure in the critically ill.

We have prospectively investigated the effect of a flexible approach to the management of acute renal failure in critically ill patients based on continuous haemodiafiltration (CHD). Fifty critically ill patients (mean APACHE II score 28.1, range 18-37), with a mean age of 59.5 years, were treated with continuous arteriovenous haemodiafiltration (CAVHD) and/or continuous venovenous haemodiafiltration (CVVHD). CHD achieved excellent haemodynamic stability and control of azotaemia in all patients and permitted aggressive parenteral nutrition. The mean blood urea concentration fell from 33.9 mmol/l (95% confidence interval, CI, 29.1-38.7) to a plateau of 17 mmol/l (95% CI 14.3-19.7) after 72 h of therapy despite persistent anuria and the parenteral administration of 0.3 g/kday of protein nitrogen (mean urea clearance: 24.2 ml/min; 95% CI 22.9-25.5). No supplemental dialytic therapy was required during the 9,485 h of treatment. All clinically significant complications related to vascular access (14%). Twenty-two patients (44%) survived to be discharged from the ICU. CHD is relatively safe and effective in the management of acute renal failure in the critically ill.

Acute Kidney Injury↗
PubMed1992

Management of acute renal failure in the critically ill with continuous venovenous hemodiafiltration.

Continuous venovenous hemodiafiltration (CVVHD) has been increasingly utilized for renal replacement therapy in the critically ill. We report details of a prospective study of CVVHD in 12 critically ill patients (7 males, 5 females; mean age 60 years, range 30-72 years; Apache II score mean 27.4, range 21-35) with oligoanuric acute renal failure supported on CVVHD. Vascular access was obtained via double lumen subclavian or femoral cannulae. The mean pretreatment urea was 35.9 mM/L and the mean pretreatment creatinine was 559 microM/L. After 24 h of treatment on CVVHD these fell to a urea mean of 20.3 mM/L and a creatinine mean of 298 microM/L and remained stable at these values for the duration of CVVHD. The mean net ultrafiltrate volume was 551 mL/h, with a urea clearance mean of 26.6 mL/min and a creatinine clearance mean of 23.7 mL/min. There were no complications related to use of the blood pump module or extracorporeal circuit. Excellent hemodynamic stability, control of fluid and electrolyte balance, and azotaemia control were maintained while on CVVHD. Technique survival was 100%. Patient survival was 42%. We conclude that CVVHD is a safe, effective, and durable therapy for the treatment of acute renal failure in the critically ill and that it offers outstanding metabolic control and cardiovascular stability.

Acute Kidney Injury↗
PubMed1992

Acute continuous hemofiltration with dialysis: effect on insulin concentrations and glycemic control in critically ill patients.

OBJECTIVES: To quantitate insulin losses and glucose absorption during acute continuous hemofiltration with dialysis and to assess the clinical importance of these changes. DESIGN: Prospective collection of serum and ultradiafiltrate fluid in patients receiving acute continuous hemofiltration with dialysis. Measurements of serum and ultradiafiltrate insulin and glucose concentrations. Calculations of insulin excretion and glucose absorption. Correlation of findings with patient outcome. SETTING: University medical center. PATIENTS: Sixteen ICU patients with acute renal failure. MEASUREMENTS AND MAIN RESULTS: The mean serum glucose concentration before acute continuous hemofiltration with dialysis was 178 mg/dL (9.9 mmol/L) (95% confidence interval 112 to 244 mg/dL [6.2 to 13.6 mmol/L]), increasing to 257 mg/dL (14.3 mmol/L) (95% confidence interval 167 to 347 mg/dL [9.3 to 19.3 mmol/L]) after 4 hrs of acute continuous hemofiltration with dialysis, and stabilizing at 207 mg/dL (11.5 mmol/L) (95% confidence interval 160 to 254 mg/dL [8.9 to 14.1 mmol/L]) at 24 hrs. Mean plasma insulin concentration before acute continuous hemofiltration with dialysis was 34.4 mU/L (95% confidence interval 8.6 to 60.2 mU/L), increasing to 54.4 mU/L at 4 hrs (95% confidence interval 25 to 83.8 mU/L; NS). There was no significant decrease in mean insulin concentration across the filter (51.8 mU/L before filtration vs. 51.9 mU/L after filtration). Insulin was detected in the ultradiafiltrate but its overall mean clearance rate was only 6.2 mL/min, with mean daily losses of 689 mU/day (95% confidence interval 325 to 1053 mU/day). During acute continuous hemofiltration with dialysis, glucose absorption through the filter averaged 134 g/day (95% confidence interval 96.2 to 171.8 g/day). Plasma insulin concentrations were significantly (p < .05) lower in survivors than nonsurvivors (51.7 vs. 123.6 mU/L). CONCLUSIONS: Significant glucose absorption occurs during acute continuous hemofiltration with dialysis and is coupled with minor insulin losses (< 1 U/day) through the filter. These events do not appear to have major clinical impact. A low plasma insulin concentration is associated with diminished mortality rates in this group of patients.

Acute Kidney Injury↗
PubMed1991

Continuous arteriovenous haemodiafiltration in the critically ill: influence on major nutrient balances.

The impact of continuous arteriovenous haemodiafiltration (CAVHD) on nitrogen, lipid and carbohydrate balance was studied in 9 parenterally fed critically ill patients with acute renal failure. The effects on carbohydrate delivery of varying dialysate glucose concentrations or flow rates were also investigated. The total daily nitrogen loss was a mean of 24.1 g (95% CI 20.9-27.3 g/24 h) with non-urea nitrogen losses of 7.6 g (95% CI 5.6-9.6 g/24 h). Glucose delivery was a mean 5.8 g/h with a dialysate glucose concentration of 1.5% and a flow rate of 1 l/h (95% CI 4.5-7.0 g/h). Carbohydrate delivery increased with increased dialysate glucose concentration (mean 11.4 g/h with 2.5% glucose: 95% CI 9.6-13.1 g/h; mean 14.9 g/h with a 4.25% concentration: 95% CI 10.9-19; and with increased dialysate flow rates (mean 9.6 g/h, 95% CI 6.8-12.4 g/h, using 2 l/h of 1.5% glucose). Only trace amounts of cholesterol and/or triglycerides were detected in occasional ultradiafiltrate samples. CAVHD has an important impact on nitrogen and carbohydrate balance, but not on lipid status. Knowledge of these interactions is crucial for the rational planning of nutritional strategies in the critically ill.

Acute Kidney Injury↗