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Shigehiko Uchino

Publications and source records attributed to Shigehiko Uchino.

At least 19 recordsLinked to original sources

Recent clinical advances in the management of critically ill patients with acute renal failure.

BACKGROUND: Significant progress has been made in the field of renal replacement therapy for critically ill patients with acute renal failure (ARF) over the past few years. This review highlights these developments. METHODS: Recent studies assessing the clinical utility of the RIFLE classification system for the diagnosis of ARF were reviewed. Clinical outcome studies evaluating the effect of continuous renal replacement therapy (CRRT) dose and timing of initiation were assessed. The final review topic was the effect of dialysis modality on the recovery of renal function in ARF patients. CONCLUSIONS: Based on recent clinical studies, the increasing use of the RIFLE criteria is justified, as this approach appears to be a robust method for both the diagnosis of and prognostication in ARF. A large randomized trial involving convective CRRT supports the commonly used prescription of 35 ml/ kg/h in clinical practice. Moreover, numerous recent outcome studies, also largely involving convective CRRT, provide a clinical rationale for the increasingly common clinical practice of earlier initiation. Finally, several recent studies suggest CRRT, relative to conventional hemodialysis, results in a greater rate of renal recovery in ARF patients.

Acute Kidney Injury↗

An assessment of the RIFLE criteria for acute renal failure in hospitalized patients.

OBJECTIVE: The Acute Dialysis Quality Initiative (ADQI) Group published a consensus definition (the RIFLE criteria) for acute renal failure. We sought to assess the ability of the RIFLE criteria to predict mortality in hospital patients. DESIGN: Retrospective single-center study. SETTING: University-affiliated hospital. PATIENTS: All patients admitted to the study hospital between January 2000 and December 2002. Patients were excluded if they were younger than 15 yrs old, were on chronic dialysis, or had kidney transplant or if their length of hospital stay was <24 hrs. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We included 20,126 patients. Mean age was 64 yrs, 14.7% of patients required intensive care unit admission, and hospital mortality was 8.0%. According to the RIFLE criteria, 9.1% of all patients were in the Risk category for acute renal failure, 5.2% were in the Injury category, and 3.7% were in the Failure category. There was an almost linear increase in hospital mortality from Normal to Failure (Normal, 4.4%; Risk, 15.1%; Injury, 29.2%; and Failure, 41.1%). Multivariate logistic regression analysis showed that all RIFLE criteria were significantly predictive factors for hospital mortality, with an almost linear increase in odds ratios from Risk to Failure (odds ratios, Risk 2.5, Injury 5.4, Failure 10.1). CONCLUSIONS: The RIFLE criteria for acute renal failure classified close to 20% of our study patients as having some degrees of acute impairment in renal function and were useful in predicting their hospital mortality.

Acute Kidney Injury↗

The effects of saline or albumin resuscitation on acid-base status and serum electrolytes.

OBJECTIVE: To test whether fluid resuscitation with normal saline or 4% albumin is associated with differential changes in acid-base status and serum electrolytes. DESIGN: Nested cohort study. SETTING: Three general intensive care units. PATIENTS: Six hundred and ninety-one critically ill patients. INTERVENTIONS: Randomization of patients to receive blinded solutions of either 4% human albumin or normal saline for fluid resuscitation. MEASUREMENTS AND MAIN RESULTS: Albumin was given to 339 patients and saline to 352. At baseline, both groups had a similar serum bicarbonate, albumin, and base excess levels. After randomization, bicarbonate and base excess increased significantly and similarly over time (p < .0001). On multivariate analysis, fluid resuscitation with albumin predicted a smaller increase in pH (p = .0051), bicarbonate (p = .034), and base excess (p = .015). The amount of fluid was an independent predictor of pH (p < .0001), serum chloride (p < .0001), calcium (p = .0001), bicarbonate (p = .0002), and base excess (p < .0001) on the first day of treatment. In patients who received >3 L of fluids in the first 24 hrs, albumin administration was associated with a significantly greater increase in serum chloride (p = .0026). Acute Physiology and Chronic Health Evaluation II score and the presence of sepsis also independently predicted changes in several electrolytes and acid-base variables. CONCLUSIONS: When comparing albumin and saline, the choice and amount of resuscitation fluid are independent predictors of acid-base status and serum electrolytes. When large volumes are given, albumin administration leads to a higher chloride concentration. However, overall differences between the types of fluid are minor, whereas the volume of fluid administered is a much stronger predictor of such changes, which are also influenced by illness severity and the passage of time.

Acid-Base Equilibrium↗

The epidemiology of acute renal failure in the world.

PURPOSE OF REVIEW: The aim of this article is to describe our current understanding of the epidemiology of acute renal failure, especially in severe cases requiring renal replacement therapy. Some data from an international observational study (the Beginning and Ending Supportive Therapy (BEST) for the kidney study) are also presented. RECENT FINDINGS: Multiple epidemiological studies for acute renal failure have been conducted in different populations using various criteria and reported a wide range of incidence and mortality. In several multicenter studies reporting the incidence of renal replacement therapy requirement in a general intensive care unit population, however, renal replacement therapy requirement and hospital mortality was quite similar among the studies, approximately 4% and 60%, respectively. In North and South America, nephrologists typically manage acute renal failure patients with intermittent renal replacement therapy. On the other hand, in Asia, Australia and Europe, intensivists are commonly responsible for managing these patients with continuous renal replacement therapy. SUMMARY: Although the epidemiology of acute renal failure is varied among regions and centers, the average incidence of renal replacement therapy requirement and hospital mortality in critical illness are similar in multicenter studies. Continuous renal replacement therapy is gaining popularity and intensivists are becoming responsible for managing patients with it. More studies are needed to understand acute renal failure epidemiology worldwide. To conduct such studies, consensus criteria for acute renal failure and a well performed acute renal failure-specific severity score will be required.

Acute Kidney Injury↗

Pulmonary artery catheter versus pulse contour analysis: a prospective epidemiological study.

INTRODUCTION: The choice of invasive systemic haemodynamic monitoring in critically ill patients remains controversial as no multicentre comparative clinical data exist. Accordingly, we sought to study and compare the features and outcomes of patients who receive haemodynamic monitoring with either the pulmonary artery catheter (PAC) or pulse contour cardiac output (PiCCO) technology. METHODS: We conducted a prospective multicentre, multinational epidemiological study in a cohort of 331 critically ill patients who received haemodynamic monitoring by PAC or PiCCO according to physician preference in intensive care units (ICUs) of eight hospitals in four countries. We collected data on haemodynamics, demographic features, daily fluid balance, mechanical ventilation days, ICU days, hospital days, and hospital mortality. We statistically compared the two techniques. RESULTS: Three hundred and forty-two catheters (PiCCO 192 and PAC 150) were inserted in 331 patients. On direct comparison, patients with PAC were older (68 versus 64 years of age; p = 0.0037), were given inotropic drugs more frequently (37.3% versus 13%; p < 0.0001), and had a lower cardiac index (2.6 versus 3.2 litres/minute per square meter; p < 0.0001). Mean daily fluid balance was significantly greater during PiCCO monitoring (+659 versus +350 ml/day; p = 0.017) and mechanical ventilation-free days were fewer (12 for PiCCO versus 21 for PAC; p = 0.045). However, after multiple regression analysis, we found no significant effect of monitoring technique on mean daily fluid balance, mechanical ventilation-free days, ICU-free days, or hospital mortality. A secondary multiple logistic regression analysis for hospital mortality which included mean daily fluid balance showed that positive fluid balance was a significant predictor of hospital mortality (odds ratio = 1.0002 for each ml/day; p = 0.0073). CONCLUSION: On direct comparison, the use of PiCCO was associated with a greater positive fluid balance and fewer ventilator-free days. After correction for confounding factors, the choice of monitoring did not influence major outcomes, whereas a positive fluid balance was a significant independent predictor of outcome. Future studies may best be targeted at understanding the effect of pursuing different fluid balance regimens rather than monitoring techniques per se.

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Acute renal failure in critically ill patients: a multinational, multicenter study.

CONTEXT: Although acute renal failure (ARF) is believed to be common in the setting of critical illness and is associated with a high risk of death, little is known about its epidemiology and outcome or how these vary in different regions of the world. OBJECTIVES: To determine the period prevalence of ARF in intensive care unit (ICU) patients in multiple countries; to characterize differences in etiology, illness severity, and clinical practice; and to determine the impact of these differences on patient outcomes. DESIGN, SETTING, AND PATIENTS: Prospective observational study of ICU patients who either were treated with renal replacement therapy (RRT) or fulfilled at least 1 of the predefined criteria for ARF from September 2000 to December 2001 at 54 hospitals in 23 countries. MAIN OUTCOME MEASURES: Occurrence of ARF, factors contributing to etiology, illness severity, treatment, need for renal support after hospital discharge, and hospital mortality. RESULTS: Of 29 269 critically ill patients admitted during the study period, 1738 (5.7%; 95% confidence interval [CI], 5.5%-6.0%) had ARF during their ICU stay, including 1260 who were treated with RRT. The most common contributing factor to ARF was septic shock (47.5%; 95% CI, 45.2%-49.5%). Approximately 30% of patients had preadmission renal dysfunction. Overall hospital mortality was 60.3% (95% CI, 58.0%-62.6%). Dialysis dependence at hospital discharge was 13.8% (95% CI, 11.2%-16.3%) for survivors. Independent risk factors for hospital mortality included use of vasopressors (odds ratio [OR], 1.95; 95% CI, 1.50-2.55; P<.001), mechanical ventilation (OR, 2.11; 95% CI, 1.58-2.82; P<.001), septic shock (OR, 1.36; 95% CI, 1.03-1.79; P = .03), cardiogenic shock (OR, 1.41; 95% CI, 1.05-1.90; P = .02), and hepatorenal syndrome (OR, 1.87; 95% CI, 1.07-3.28; P = .03). CONCLUSION: In this multinational study, the period prevalence of ARF requiring RRT in the ICU was between 5% and 6% and was associated with a high hospital mortality rate.

Acute Kidney Injury↗

A quantitative analysis of the acidosis of cardiac arrest: a prospective observational study.

INTRODUCTION: Metabolic acidosis is common in patients with cardiac arrest and is conventionally considered to be essentially due to hyperlactatemia. However, hyperlactatemia alone fails to explain the cause of metabolic acidosis. Recently, the Stewart-Figge methodology has been found to be useful in explaining and quantifying acid-base changes in various clinical situations. This novel quantitative methodology might also provide useful insight into the factors responsible for the acidosis of cardiac arrest. We proposed that hyperlactatemia is not the sole cause of cardiac arrest acidosis and that other factors participate significantly in its development. METHODS: One hundred and five patients with out-of-hospital cardiac arrest and 28 patients with minor injuries (comparison group) who were admitted to the Emergency Department of a tertiary hospital in Tokyo were prospectively included in this study. Serum sodium, potassium, ionized calcium, magnesium, chloride, lactate, albumin, phosphate and blood gases were measured as soon as feasible upon arrival to the emergency department and were later analyzed using the Stewart-Figge methodology. RESULTS: Patients with cardiac arrest had a severe metabolic acidosis (standard base excess -19.1 versus -1.5; P < 0.0001) compared with the control patients. They were also hyperkalemic, hypochloremic, hyperlactatemic and hyperphosphatemic. Anion gap and strong ion gap were also higher in cardiac arrest patients. With the comparison group as a reference, lactate was found to be the strongest determinant of acidosis (-11.8 meq/l), followed by strong ion gap (-7.3 meq/l) and phosphate (-2.9 meq/l). This metabolic acidosis was attenuated by the alkalinizing effect of hypochloremia (+4.6 meq/l), hyperkalemia (+3.6 meq/l) and hypoalbuminemia (+3.5 meq/l). CONCLUSION: The cause of metabolic acidosis in patients with out-of-hospital cardiac arrest is complex and is not due to hyperlactatemia alone. Furthermore, compensating changes occur spontaneously, attenuating its severity.

Acidosis↗

External validation of severity scoring systems for acute renal failure using a multinational database.

OBJECTIVE: Several different severity scoring systems specific to acute renal failure have been proposed. However, most validation studies of these scoring systems were conducted in a single center or in a small number of centers, often the same ones used for their development. Therefore, it is not known whether such severity scoring systems may be widely applied. DESIGN: Prospective clinical investigation. SETTING: Intensive care units. PATIENTS: One thousand seven hundred and forty-two intensive care unit patients with acute renal failure who were either treated with renal replacement therapy or fulfilled predefined criteria. INTERVENTIONS: Demographic and clinical information and outcomes were measured. MEASUREMENTS AND MAIN RESULTS: Scores for four acute renal failure-specific scoring systems and two general scoring systems (Simplified Acute Physiology Score II and Sequential Organ Failure Assessment) were calculated, and their discrimination and calibration were tested with receiver operating characteristic curves and Hosmer-Lemeshow goodness-of fit-tests. For the receiver operating characteristic curves, blood lactate levels were also used as a reference. All scores had an area under the receiver operating characteristic curve <0.7 (Mehta 0.670, Liano 0.698, Chertow 0.610, Paganini 0.643, Simplified Acute Physiology Score II 0.645, Sequential Organ Failure Assessment 0.675, lactate 0.639). For scores that can calculate predicted mortality, the Hosmer-Lemeshow goodness-of-fit test showed poor calibration. CONCLUSIONS: None of the scoring systems tested had a high level of discrimination or calibration to predict mortality for patients with acute renal failure when tested in a broad cohort of patients from multiple countries. A large, multiple-center database might be needed to improve the discrimination and calibration of acute renal failure scoring system.

Acute Kidney Injury↗

Hidden evidence to the West: multicentre, randomised, controlled trials in sepsis and systemic inflammatory response syndrome in Japanese journals.

OBJECTIVE: To assess multicentre, randomised, controlled trials (MC-RCTs) of systemic inflammatory response syndrome (SIRS) and sepsis conducted in Japan, published in Japanese and not available to English-language medical databases. DESIGN: Methodological review. SUBJECTS: All Japanese RCTs relevant to SIRS and sepsis. INTERVENTION: Identification of manuscripts using a Japanese electronic library. Critical analysis of methodology and reporting quality using a modified Methodological Quality Assessment Score and the CONSORT group check list. MEASUREMENTS AND RESULTS: Three MC-RCTs were identified. In the first, 147 patients with septic shock were randomised to methylprednisolone (1000 mg i.v.) or placebo. In the second, 221 patients were randomised to 0.20 mg/kg per h or 0.004 mg/kg per h of sivelestat for acute lung injury with SIRS. In the third, 504 patients were randomised to immunoglobulin (5 g for 3 days) or to a control group. The average methodological quality score was higher than that of equivalent Western trials. The reporting quality (CONSORT checklist) was comparable to Western studies published during the same period. CONCLUSIONS: Despite sound methodology and quality, the information obtained from relatively large Japanese critical care trials is not widely available to English-speaking investigators and therefore might be ignored in meta-analyses.

Anti-Inflammatory Agents↗

Early and exclusive use of norepinephrine in septic shock.

BACKGROUND: The timing and use of norepinephrine (noradrenaline) (NE) in septic shock remain a matter of controversy. AIM: To study the outcome of septic patients treated with early and exclusive NE. SETTING: Tertiary Intensive Care Unit. PATIENTS: 142 patients with septic shock. INTERVENTION: Exclusive NE infusion within 24 hours of admission to ICU. METHODS AND MAIN RESULTS: Retrospective analysis of data from a unit database identified 142 patients. Their median admission simplified acute physiology score (SAPS II) score was 46 [38, 56] with 98 (69%) receiving mechanical ventilation. Mean arterial pressure (MAP) at the start of NE infusion was 60 [58, 68]mmHg. NE infusion was started at a median of 1.3 [0.3, 5.0]h after ICU admission. Restoration and maintenance of target MAP was achieved initially in all patients and, in 61.3%, within 30 min. The median peak dose of NE was 0.28 [0.14, 0.61]microg/(kg min) and the duration of infusion was 88 [42, 175]h. SAPS II predicted mortality was 40.8%, however, only 34.5% (P = 0.27) died. Among the most severely ill patients (SAPS II score >56) actual mortality was 50.0% versus 74.7% predicted (P = 0.07). CONCLUSIONS: Early and exclusive use of NE in hyperdynamic septic shock achieved a stable MAP >75 mmHg in all patients. Survival compared favorably with that predicted by illness severity scores.

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Electrolyte mass balance during CVVH: lactate vs. bicarbonate-buffered replacement fluids.

OBJECTIVE: To compare the effect of lactate vs. bicarbonate-buffered replacement fluids on electrolyte mass balance during isovolemic continuous veno-venous hemofiltration (CVVH). DESIGN: Randomized controlled study with double cross over. SETTING: Intensive care unit of a tertiary university hospital. PATIENTS AND PARTICIPANTS: Eight patients with acute renal failure (ARF). INTERVENTIONS: Isovolemic CVVH (2L/hr of replacement fluid) was performed in random order with either bicarbonate or lactate-buffered replacement fluid delivered pre-filter. MEASUREMENTS AND RESULTS: Sodium, potassium, chloride, magnesium, and phosphate, were measured in each sample. There was a mass gain of sodium, which was similar under both conditions (bicarbonate: 23.3+/-4.9 mmol/hr, lactate: 22.7+/-3.5 mmol/hr). Mass chloride gains occurred with bicarbonate-buffered replacement fluid only (12.8+/-5.3 mmol/hr), while there was an overall net loss of chloride with lactate fluids (-2.5+/-5.2 mmol/hr), resulting in a significant difference in chloride mass balance (p<0.0001). Magnesium mass balance was negative with bicarbonate buffer only (-0.6+/-0.2 mmol/hr) and also differed significantly from that obtained with lactate fluids (-0.1+/-0.2 mmol/hr, p<0.0001). Phosphate losses (bicarbonate: -1.7+/-0.7 mmol/hr, lactate: -1.7+/-0.5 mmol/hr) were equivalent with both buffers. Potassium mass balance was neutral. CONCLUSIONS: Mass balance during isovolemic CVVH is significantly affected by the type of replacement fluid administered prefilter. Isovolemic CVVH is not isonatremic and the use of bicarbonate-buffered fluid results in a significant accumulation of chloride and a loss of magnesium.

Acute Kidney Injury↗

Prospective controlled trial of effect of medical emergency team on postoperative morbidity and mortality rates.

OBJECTIVE: To determine whether the introduction of an intensive care unit-based medical emergency team, responding to hospital-wide preset criteria of physiologic instability, would decrease the rate of predefined adverse outcomes in patients having major surgery. DESIGN: Prospective, controlled before-and-after trial. SETTING: University-affiliated hospital. PATIENTS: Consecutive patients admitted to hospital for major surgery during a 4-month control phase and during a 4-month intervention phase. INTERVENTIONS: Introduction of a hospital-wide intensive care unit-based medical emergency team to evaluate and treat in-patients deemed at risk of developing an adverse outcome by nursing, paramedical, and/or medical staff. MEASUREMENTS AND MAIN RESULTS: We measured incidence of serious adverse events, mortality after major surgery, and mean duration of hospital stay. There were 1,369 operations in 1,116 patients during the control period and 1,313 in 1,067 patients during the medical emergency team intervention period. In the control period, there were 336 adverse outcomes in 190 patients (301 outcomes/1,000 surgical admissions), which decreased to 136 in 105 patients (127 outcomes/1,000 surgical admissions) during the intervention period (relative risk reduction, 57.8%; p <.0001). These changes were due to significant decreases in the number of cases of respiratory failure (relative risk reduction, 79.1%; p <.0001), stroke (relative risk reduction, 78.2%; p =.0026), severe sepsis (relative risk reduction, 74.3%; p =.0044), and acute renal failure requiring renal replacement therapy (relative risk reduction, 88.5%; p <.0001). Emergency intensive care unit admissions were also reduced (relative risk reduction, 44.4%; p =.001). The introduction of the medical emergency team was also associated with a significant decrease in the number of postoperative deaths (relative risk reduction, 36.6%; p =.0178). Duration of hospital stay after major surgery decreased from a mean of 23.8 days to 19.8 days (p =.0092). CONCLUSIONS: The introduction of an intensive care unit-based medical emergency team in a teaching hospital was associated with a reduced incidence of postoperative adverse outcomes, postoperative mortality rate, and mean duration of hospital stay.

Adult↗

Diuretics and mortality in acute renal failure.

OBJECTIVE: According to recent research, diuretics may increase mortality in acute renal failure patients. The administration of diuretics in such patients has been discouraged. Our objective was to determine the impact of diuretics on the mortality rate of critically ill patients with acute renal failure. DESIGN: Prospective, multiple-center, multinational epidemiologic study. SETTING: Intensive care units from 54 centers and 23 countries. PATIENTS: Patients were 1,743 consecutive patients who either were treated with renal replacement therapy or fulfilled predefined criteria for acute renal failure. INTERVENTIONS: Three distinct multivariate models were developed to assess the relationship between diuretic use and subsequent mortality: a) a propensity score adjusted multivariate model containing terms previously identified to be important predictors of outcome; b) a new propensity score adjusted multivariate model; and c) a multivariate model developed using standard methods, compensating for collinearity. MEASUREMENTS AND MAIN RESULTS: Approximately 70% of patients were treated with diuretics at study inclusion. Mean age was 68 and mean Simplified Acute Physiology Score II was 47. Severe sepsis/septic shock (43.8%), major surgery (39.1), low cardiac output (29.7), and hypovolemia (28.2%) were the most common conditions associated with the development of acute renal failure. Furosemide was the most common diuretic used (98.3%). Combination therapy was used in 98 patients only. In all three models, diuretic use was not associated with a significantly increased risk of mortality. CONCLUSIONS: Diuretics are commonly prescribed in critically ill patients with acute renal failure, and their use is not associated with higher mortality. There is full equipoise for a randomized controlled trial of diuretics in critically ill patients with renal dysfunction.

Acute Kidney Injury↗

A prospective before-and-after trial of a medical emergency team.

OBJECTIVE: To determine the effect on cardiac arrests and overall hospital mortality of an intensive care-based medical emergency team. DESIGN AND SETTING: Prospective before-and-after trial in a tertiary referral hospital. PATIENTS: Consecutive patients admitted to hospital during a 4-month "before" period (May-August 1999) (n = 21 090) and a 4-month intervention period (November 2000 -February 2001) (n = 20 921). MAIN OUTCOME MEASURES: Number of cardiac arrests, number of patients dying after cardiac arrest, number of postcardiac-arrest bed-days and overall number of in-hospital deaths. RESULTS: There were 63 cardiac arrests in the "before" period and 22 in the intervention period (relative risk reduction, RRR: 65%; P < 0.001). Thirty-seven deaths were attributed to cardiac arrests in the "before" period and 16 in the intervention period (RRR: 56%; P = 0.005). Survivors of cardiac arrest in the "before" period required 163 ICU bed-days versus 33 in the intervention period (RRR: 80%; P < 0.001), and 1353 hospital bed-days versus 159 in the intervention period (RRR: 88%; P < 0.001). There were 302 deaths in the "before" period and 222 in the intervention period (RRR: 26%; P = 0.004). CONCLUSIONS: The incidence of in-hospital cardiac arrest and death following cardiac arrest, bed occupancy related to cardiac arrest, and overall in-hospital mortality decreased after introducing an intensive care-based medical emergency team.

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Solute mass balance during isovolaemic high volume haemofiltration.

OBJECTIVE: To evaluate the effect of changing the amount of pre-dilution replacement fluid on the sieving coefficient (SC) and mass transfer of small solutes during isovolaemic high-volume haemofiltration (HVHF). DESIGN AND SETTING: Prospective interventional study in the intensive care unit of a tertiary university hospital. PATIENTS: Eight patients with septic shock. INTERVENTIONS: Isovolaemic HVHF (6 l/h of replacement fluid) was performed. The proportion of replacement fluid delivered in pre-filter was altered to progressively decrease it from 6 to 0 l/h. Samples were simultaneously taken from the "pre-filter", "post-filter" and ultrafiltrate (UF) sampling ports. MEASUREMENTS AND RESULTS: Sodium, potassium, chloride, total calcium, total magnesium, phosphate, total CO(2), urea, creatinine and glucose concentrations were measured in each sample. The sieving coefficients of chloride, total CO(2), phosphate, urea and glucose were higher than 1 in most pre-dilution states. The sieving coefficients of sodium, potassium, calcium, magnesium, total CO(2) and urea decreased significantly with decreasing pre-dilution fluid rate. The sieving coefficients of chloride and glucose increased with decreasing pre-dilution fluid rate. There was a significant mass gain of sodium and glucose under all pre-dilution conditions. Mass chloride gains decreased with decreasing pre-dilution rates and changed into chloride loss during 6 l/h of post-dilution. Decreasing pre-dilution improved urea and creatinine mass removal. CONCLUSIONS: Small solute SC and mass transfer during isovolaemic HVHF are significantly affected by the proportion of replacement fluid administered pre-filter. Isovolaemic HVHF is neither isonatraemic nor isochloraemic.

Adult↗

Acid-base status of critically ill patients with acute renal failure: analysis based on Stewart-Figge methodology.

INTRODUCTION: The aim of the present study is to understand the nature of acid-base disorders in critically ill patients with acute renal failure (ARF) using the biophysical principles described by Stewart and Figge. A retrospective controlled study was carried out in the intensive care unit of a tertiary hospital. MATERIALS AND METHODS: Forty patients with ARF, 40 patients matched for Acute Physiology and Chronic Health Evaluation II score (matched control group), and 60 consecutive critically ill patients without ARF (intensive care unit control group) participated. The study involved the retrieval of biochemical data from computerized records, quantitative biophysical analysis using the Stewart-Figge methodology, and statistical comparison between the three groups. We measured serum sodium, potassium, magnesium, chloride, bicarbonate, phosphate, ionized calcium, albumin, lactate and arterial blood gases. RESULTS: Intensive care unit patients with ARF had a mild acidemia (mean pH 7.30 +/- 0.13) secondary to metabolic acidosis with a mean base excess of -7.5 +/- 7.2 mEq/l. However, one-half of these patients had a normal anion gap. Quantitative acid-base assessment (Stewart-Figge methodology) revealed unique multiple metabolic acid-base processes compared with controls, which contributed to the overall acidosis. The processes included the acidifying effect of high levels of unmeasured anions (13.4 +/- 5.5 mEq/l) and hyperphosphatemia (2.08 +/- 0.92 mEq/l), and the alkalinizing effect of hypoalbuminemia (22.6 +/- 6.3 g/l). CONCLUSIONS: The typical acid-base picture of ARF of critical illness is metabolic acidosis. This acidosis is the result of the balance between the acidifying effect of increased unmeasured anions and hyperphosphatemia and the lesser alkalinizing effect of hypoalbuminemia.

Acid-Base Equilibrium↗

Norepinephrine for hypotensive vasodilatation after cardiac surgery: impact on renal function.

OBJECTIVES: Norepinephrine use in patients after cardiac surgery is controversial because of the fear that norepinephrine might decrease kidney function through regional vasoconstriction. Accordingly, we studied the renal effects of norepinephrine use for hypotensive vasodilatation after cardiac surgery. DESIGN AND SETTING: Retrospective controlled study in the cardiothoracic ICU of tertiary hospital. PATIENTS. 100 cardiac surgery patients with post-operative hypotensive vasodilatation and 100 control cardiac surgery patients. INTERVENTION: Treatment of hypotension (MAP<70 mmHg) with continuous norepinephrine infusion. MEASUREMENTS AND RESULTS: We collected data on demographic and surgical characteristics, haemodynamics, serum creatinine and mortality. Just after surgery the norepinephrine group had a significantly higher mean central venous pressure, lower mean arterial pressure, and lower systemic vascular resistance index with a similarly elevated mean cardiac index. Despite norepinephrine administration at a mean peak dose of 7.3+/-6.4 micro g/min the mean post-operative change in creatinine was not different between two groups on days 0, 2 or 4 after surgery. CONCLUSIONS: Norepinephrine does not increase post-operative serum creatinine concentrations in patients with hypotensive vasodilatation after cardiac surgery. Concerns related to its potential adverse effects on the kidney function in this setting appear unjustified.

Aged↗

Continuous is not continuous: the incidence and impact of circuit "down-time" on uraemic control during continuous veno-venous haemofiltration.

OBJECTIVE: There is little information on the duration of time that patients spend off therapy (down-time) during continuous veno-venous haemofiltration (CVVH) and the effect of this treatment free time on azotaemic control. DESIGN AND SETTING: Prospective observational study in the ICU of tertiary hospital. PATIENTS AND PARTICIPANTS: 48 critically ill patients treated with CVVH at 2 l/h of ultrafiltration. INTERVENTIONS: Prospective collection of demographic and biochemical data. MEASUREMENTS AND RESULTS: Two hundred and sixty-six filters were observed. Start and end times were collected for each filter. Creatinine and urea were measured daily and percentage of reduction of these two solutes was calculated (%Delta creatinine and urea). The median period when CVVH was not applied to a patient (down-time) was 3 h per day. There was a significant inverse correlation between down-time and %Delta creatinine and urea over each 24-h time cycle. On average at least 16 h per day of CVVH was required to maintain creatinine and urea concentration for each 24-h cycle. CONCLUSIONS: "Continuous" therapy is not truly continuous. Down-time adversely affects azotaemic control. Physicians prescribing CRRT should be aware of the consequences of such down-time on the quality and quantity of renal replacement therapy delivered.

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