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R Bellomo

Publications and source records attributed to R Bellomo.

At least 19 recordsLinked to original sources
PubMed2006

Renal blood flow in experimental septic acute renal failure.

Reduced renal blood flow (RBF) is considered central to the pathogenesis of septic acute renal failure (ARF). However, no controlled experimental studies have continuously assessed RBF during the development of severe septic ARF. We conducted a sequential animal study in seven female Merino sheep. Flow probes were implanted around the pulmonary and left renal arteries. Two weeks later, systemic hemodynamics and RBF were monitored continuously during a 48-h control period and, after a week, during a 48-h period of hyperdynamic sepsis induced by continuous Escherichia coli infusion. Infusion of E. coli induced hyperdynamic sepsis with significantly increased cardiac output (3.8+/-0.4 vs 9.8+/-1.1 l/min; P<0.05), decreased mean arterial pressure (89.2+/-3.2 vs 64.3+/-5.3 mm Hg; P<0.05), and increased total peripheral conductance (42.8+/-3.5 in controls vs 153.7+/-24.7 ml/min/mm Hg in septic animals; P<0.05). Hyperdynamic sepsis was associated with marked renal vasodilatation (renal conductance: 3.0+/-0.7 vs 11.4+/-3.4 ml/min/mm Hg; P<0.05) and a marked increase in RBF (262.3+/-47.7 vs 757.4+/-250.1 ml/min; P<0.05). Serum creatinine increased over 48 h (73+/-18 vs 305+/- micromol/l; P<0.05) whereas creatinine clearance decreased (95.5+/-25.9 vs 20.1+/-19.3 ml/min; P<0.05). After 24 h, urine output decreased from 1.4 to 0.3 ml/kg/h (P<0.05). Infusion of E. coli induced hyperdynamic sepsis and ARF. Septic ARF in this setting was associated with a marked increase in RBF and with renal vasodilatation.

Acute Kidney Injury↗
PubMed2006

Do we know the optimal dose for renal replacement therapy in the intensive care unit?

Increasing the dose of renal replacement therapy might increase survival in critically ill patients with acute renal failure. For continuous renal replacement therapy (CRRT), a single-center study suggests that increasing urea clearance from 20 ml/kg/h to 35-45 ml/kg/h might increase short-term survival. A further single-center study has now confirmed that the dose of CRRT might be a determinant of outcome. This issue is now being addressed by two large multicenter randomized controlled trials in the United States (the ATN study) and Australia and New Zealand (the RENAL study). The results of these two studies should be available in 2008. Before making any major changes to practice, it seems prudent to wait for the publication of the findings of these two pivotal trials.

Acute Kidney Injury↗
PubMed2006

Effect of an education programme on the utilization of a medical emergency team in a teaching hospital.

BACKGROUND: Medical Emergency Teams (MET) have been developed to identify, review and manage acutely unwell ward patients. Previous studies have suggested that there may be obstacles to the utilization and activation of the MET. AIMS: To determine the effect of a detailed education programme on the rate of utilization of the MET system 3.5 years after its introduction in a University teaching hospital. METHODS: Prospective interventional study involving a detailed programme of education, feedback and decision support for nursing and medical staff given before, during and after implementation of a MET system. We measured the number of MET calls per month for both medical and surgical patients for 109 250 consecutive admissions to the acute care campus of Austin Health from August 2000 to June 2004. RESULTS: Overall activation of the MET increased from 25 calls per month to a peak of 79 calls per month over the study period (average increase of one MET call/month). After standardization for monthly admissions, the increase in MET utilization for surgical patients (increase by 1.13 MET/1000 admissions/month) was 4.9-fold greater than for medical patients (increase by 0.23 MET/1000 admissions/month; P < 0.0001). At the peak level of activity (April 2004), the MET was called to review 8.4% of surgical and 2.7% of medical admissions (P < 0.0001). CONCLUSIONS: There was a progressive increase in the utilization of the MET service in the 3.5 years after implementation, with the rate of uptake 4.9 times greater for surgical than for medical patients. Sustained uptake of the MET system is possible, but increased utilization may take several years to develop. Short-term studies testing the efficacy of the MET system are likely to significantly underestimate its effect on reducing adverse events. Intensive care unit resource adjustments will become necessary to meet increased demand.

Critical Illness↗
PubMed2006

Nurses' attitudes to a medical emergency team service in a teaching hospital.

BACKGROUND: Cultural barriers including allegiance to traditional models of ward care and fear of criticism may restrict use of a medical emergency team (MET) service, particularly by nursing staff. A 1-year preparation and education programme was undertaken before implementing the MET at the Austin Hospital, Melbourne, Australia. During the 4 years after introduction of the MET, the programme has continued to inform staff of the benefits of the MET and to overcome barriers restricting its use. OBJECTIVE: To assess whether nurses value the MET service and to determine whether barriers to calling the MET exist in a 400-bed teaching hospital. METHODS: Immediately before hand-over of ward nursing, we conducted a modified personal interview, using a 17-item Likert agreement scale questionnaire. RESULTS: We created a sample of 351 ward nurses and obtained a 100% response rate. This represents 50.9% of the 689 ward nurses employed at the hospital. Most nurses felt that the MET prevented cardiac arrests (91%) and helped manage unwell patients (97%). Few nurses suggested that they restricted MET calls because they feared criticism of their patient care (2%) or criticism that the patient was not sufficiently unwell to need a MET call (10%). 19% of the respondents indicated that MET calls are required because medical management by the doctors has been inadequate; many ascribed this to junior doctors and a lack of knowledge and experience. Despite hospital MET protocol, 72% of nurses suggested that they would call the covering doctor before the MET for a sick ward patient. However, 81% indicated that they would activate the MET if they were unable to contact the covering doctor. In line with hospital MET protocol, 56% suggested that they would make a MET call for a patient they were worried about even if the patient's vital signs were normal. Further, 62% indicated that they would call the MET for a patient who fulfilled MET physiological criteria but did not look unwell. CONCLUSIONS: Nurses in the Austin Hospital value the MET service and appreciate its potential benefits. The major barrier to calling the MET appears to be allegiance to the traditional approach of initially calling parent medical unit doctors, rather than fear of criticism for calling the MET service. A further barrier seems to be underestimation of the clinical significance of the physiological perturbations associated with the presence of MET call criteria.

Adult↗
PubMed2006

Perioperative pulse contour cardiac output analysis in a patient with severe cardiac dysfunction.

We describe a patient with severe left ventricular dysfunction simultaneously monitored with pulse contour cardiac output (PiCCO) analysis, a continuous cardiac output pulmonary artery catheter (continuous COPAC) and intraoperative transoesophageal echocardiography (TOE). There was good agreement between cardiac output (CO) measurements obtained by the three techniques prior to cardiopulmonary bypass (CPB). Agreement of CO measurements following CPB was initially pool; but improved following recalibration of PiCCO. PiCCO-derived global end-diastolic volume index (GEDVI) and cardiac function index (CFI), were assessed as markers of left ventricular preload and myocardial contractility, respectively. GEDVI correlated well with CO in the postoperative period. CFI increased more than two-fold following coronary revascularization and milrinone administration, and there was also a temporal relationship between the CFI and the dose of milrinone in the first 24 hours of treatment. Global end-diastolic volume and cardiac function index may be useful additional measures of left ventricular preload and myocardial contractility in patients with severe left ventricular dysfunction.

Cardiac Output↗
PubMed2006

Effect of low-dose vasopressin infusion on vital organ blood flow in the conscious normal and septic sheep.

The effect of low-dose vasopressin (AVP) on vital regional circulations may be clinically relevant but has not been fully described. We sought to determine the effect of low-dose AVP on systemic haemodynamics, coronary, mesenteric and renal circulations in the conscious normal and septic mammal. We studied seven Merino sheep using a prospective randomized cross-over double-blind placebo-controlled animal design. We inserted flow probes around aorta, coronary, mesenteric and renal arteries and, three weeks later, we infused low-dose AVP (0.02 IU/min) or placebo in the normal and septic state induced by intravenous E. coli. In normal sheep, AVP (0.02 IU/min) induced a 17% decrease in mesenteric blood flow (393.0+/-134.9 vs 472.1+/-163.8 ml/min, P<0.05) and a 14% decrease in mesenteric conductance (P<0.05). In septic sheep, AVP decreased heart rate and cardiac output by 28% and 22%, respectively (P<0.05). It also decreased mesenteric blood flow and mesenteric conductance by 23% (flow: 468.5+/-159.7 vs 611.3+/-136.3 ml/min, P<0.05; conductance: 6.3+/-2.7 vs 8.2+/-2.7 ml/min/mmHg; P<0.05). Renal blood flow was unchanged but urine output and creatinine clearance increased (P<0.05). We conclude that low-dose AVP infusion has similar effects in the normal and septic mammalian circulation: bradycardia, decreased cardiac output, decreased mesenteric blood flow and conductance and increased urine output and creatinine clearance. This information is important to clinicians considering its administration in humans.

Animals↗
PubMed2006

Relative adrenal insufficiency in etomidate-naïve patients with septic shock.

A recent study reported that 77% of patients with septic shock had relative adrenal insufficiency. However, all patients were mechanically ventilated and received high-dose inotropes. In addition, at least 24% had prior exposure to etomidate, a drug known to suppress adrenal function. We studied the incidence of relative adrenal insufficiency in etomidate-naïve patients with septic shock by analysing the adrenal response to high-dose short synacthen test in 113 consecutive patients from three university-affiliated intensive care units in Australia. Patients were allocated to three groups according to severity of illness and inclusion criteria of the trial of low dose hydrocortisone supplementation using information from patient records. Of the 113 patients, 98 had septic shock (Group A). The incidence of relative adrenal insufficiency in this subpopulation was 24.5%. Eighty-one per cent of patients with septic shock were mechanically ventilated (Group B). In this group, the incidence of relative adrenal insufficiency was 27.8%. Only 38 of the 98 patients with septic shock (39%) fulfilled inclusion criteria for the steroid supplementation trial (Group C). In this group, the incidence of relative adrenal insufficiency was only 34.2%. In all groups its presence was associated with a higher mortality. We conclude that the incidence of relative adrenal insufficiency in etomidate-naive septic shock patients was lower than observed in the steroid supplementation trial. Further, in those who fulfilled inclusion criteria for the trial, the incidence of relative adrenal insufficiency was half that reported by the trial. Our observations raise concerns about the generalizability of the findings of the above trial to etomidate-naïve patients.

APACHE↗
PubMed2006

Increasing the use of an existing medical emergency team in a teaching hospital.

Cultural barriers in hospital ward staff may limit the use of a Medical Emergency Team (MET) service. In December 2000 the role of the existing Code Blue team in our hospital was expanded to incorporate review of patients fulfilling commonly employed MET criteria. Between January 2001 and June 2003, the average call rate was only 9.8 calls/ 1000 admissions. Anecdotal feedback and a group-administered questionnaire conducted in July 2003 demonstrated a number of obstacles to initiating calls and the system was modified in October 2004. Specifically, emergency response calls were separated into Code Blue calls (for cardiorespiratory arrests) and MET calls (with physiological and worried criteria). Further loud overhead chimes as well as anaesthetist and cardiologist attendance were used only in the case of Code Blue calls (suspected arrests). Finally, the heart rate and respiratory rate criteria for MET service activation were modified. In the 12 months before the intervention (October 2003 to September 2004) there were 817 emergency response calls and 51,963 admissions (15.7 calls/1000 admissions). In the 12 months after the intervention there were 1349 emergency response calls (Code Blue plus MET calls) and 54,593 admissions (24.7 calls/1000 admissions [OR 1.59; 95% CI=1.45-1.73; P<0.0001]). Our findings suggest that increasing the use of an existing service to review patients fulfilling MET criteria requires repeated education and a periodic assessment of site-specific obstacles to utilization.

Chi-Square Distribution↗
PubMed2006

Informed consent for therapy and research in continuous renal replacement therapy: an international survey.

OBJECTIVE: To study the approach of health care workers (HCW) to informed consent for therapy and research in the field of continuous renal replacement therapy (CRRT). DESIGN: Administration of questionnaire. SETTING: Two International Courses on Critical Care Nephrology (CCN) held in Vicenza and Melbourne. PARTICIPANTS: Eight hundred and twenty one course participants. RESULTS: We obtained 349 analysable questionnaires (42.5% of participants). Only 22.5% of responders always obtain informed consent for CRRT; 70.3% just inform patients/relatives without seeking consent, 7.1% never obtain informed consent. In ICU patients, informed consent is considered 'good, correct and feasible' for therapy and for research by only 13% and 27% of responders, respectively. Consent for clinical research obtained from the next of kin or legal guardian is considered good, correct and feasible' by 56.3% of respondents, while 39.1% believe that next of kin or legal guardians can not really make informed decisions. Finally, nearly half of responders think that present rules hamper research in ICU. For many questions, significant variability of responses was found according to profession, specialty and origin of responders. CONCLUSIONS: In the field of CRRT, stated practice, beliefs and currently accepted ethical standards vary greatly according to profession, specialty and origin. A significant disagreement between what is widely promoted to be the 'correct' approach and what is currently done is evident.

Attitude of Health Personnel↗
PubMed2006

Acid-base balance during continuous veno-venous hemofiltration: the impact of severe hepatic failure.

BACKGROUND: Continuous renal replacement therapy (CRRT) affects acid-base balance but the influence of severe hepatic failure (SHF) on this effect is unknown. AIM: To assess the effect of SHF on acid-base balance in patients receiving CVVH. DESIGN: Retrospective laboratory investigation. SUBJECTS: Forty patients with SHF and acute renal failure (ARF) treated with CVVH and 42 critically ill patients with severe ARF but no liver disease also treated with CVVH (controls). INTERVENTION: Retrieval of clinical and laboratory data from prospective unit and laboratory databases. METHODS: Quantitative acid-base status assessment using the Stewart-Figge methodology. Comparison of findings between the two groups. RESULTS: Although CVVH had a major effect on acid base balance in both groups, patients with SHF had a higher mean lactate concentrations (4.8 vs. 3.1 mmol/L; p<0.0005), a greater base deficit compared to controls (-1 vs. 4.1 mEq/L; p<0.0001) and a lower PaCO 2 tension (36.8 vs. 42.5 mmHg; p<0.0001), despite the use of bicarbonate replacement fluid. The acidifying effect of hyperlactatemia was slightly worsened by an increased strong ion gap (9.3 vs. 4.9 mEq/L; p<0.0001). It was, however, attenuated by an increased strong ion difference apparent (SIDa) (43.6 vs. 41.9 mEq/L; p<0.05) secondary to hypochloremia (96 vs. 100 mmol/L; p<0.0001) and by hypoalbuminemia, although hypoalbuminemia in SHF patients (26 vs. 23; p<0.005) was less pronounced than in controls. CONCLUSION: The use of CVVH does not fully correct the independent acidifying effect of liver failure on acid-base status. Increased lactate and strong ion gap values maintain a persistent base deficit despite the alkalinizing effects of hypoalbuminemia and hypochloremia. The correction of acidosis in SHF patients may require more intensive CVVH.

Acid-Base Equilibrium↗
PubMed2005

Biologically active contaminants of intravenous saline in PVC packaging: Australasian, European, and North American samples.

We have previously found evidence of contaminants in 0.9% saline packaged in polyvinyl chloride (PVC) for clinical use. For this current study we asked two questions: (1) what are the organic chemical contaminants in solutions packaged in PVC? and (2) do the contaminants vary in bags manufactured in different countries? We studied samples of 0.9% saline packaged in PVC from Australasia, Europe, and North America. We analysed the saline solutions with high-resolution capillary gas chromatography - mass spectrometry. Components of the Australasian and European bags were also analysed using thermodesorption followed by gas chromatography and mass spectrometry. In three pairs of samples we found twenty-four different organic contaminants of the saline solutions. Diethylhexyl phthalate (DEHP) was found in all solutions; the concentrations were greater than 10 microg/l in the Australasian and European samples. All samples contained 2-ethyl hexanol (>50 microg/l), a DEHP breakdown product. The Australasian and North American samples contained cyclohexanone at concentrations of about 1000 microg/l. The cyclohexanone probably originated in joints at the bases of the bags. Both the Australasian and European bags contained t-butyl cyclohexanol (>500 microg/l) and t-butyl cyclohexanone (>50 microg/l). Printing ink on the outside of the bags was the most likely source for both of these contaminants. Several of the contaminants are toxic to animals. Little is known about the toxicity of combinations of contaminants.

Australia↗
PubMed2005

The spectrum of practice in the diagnosis and management of pneumonia in patients requiring mechanical ventilation. Australian and New Zealand practice in intensive care (ANZPIC II).

This study of ventilated patients investigated current clinical practice in 476 episodes of pneumonia (48% community-acquired pneumonia, 24% hospital-acquired pneumonia, 28% ventilator-associated pneumonia) using a prospective survey in 14 intensive care units (ICUs) within Australia and New Zealand. Diagnostic methods and confidence, disease severity, microbiology and antibiotic use were assessed. All pneumonia types had similar mortality (community-acquired pneumonia 33%, hospital-acquired pneumonia 37% and ventilator-associated pneumonia 24%, P=0.15) with no inter-hospital differences (P=0.08-0.91). Bronchoscopy was performed in 26%, its use predicted by admission hospital (one tertiary: OR 9.98, CI 95% 5.11-19.49, P< 0.001; one regional: OR 6.29, CI 95% 3.24-12.20, P<0.001), clinical signs of consolidation (OR 3.72, CI 95% 2.09-6.62, P<0.001) and diagnostic confidence (OR 2.19, CI 95% 1.29-3.72, P=0.004). Bronchoscopy did not predict outcome (P=0.11) or appropriate antibiotic selection (P=0.69). Inappropriate antibiotic prescription was similar for all pneumonia types (11-13%, P=0.12) and hospitals (0-16%, P=0.25). Blood cultures were taken in 51% of cases. For community-acquired pneumonia, 70% received a third generation cephalosporin and 65% a macrolide. Third generation cephalosporins were less frequently used for mild infections (OR 0.38, CI 95% 0.16-0.90, P=0.03), hospital-acquired pneumonia (OR 0.40, CI 95% 0.23-0.72, P<0.01), ventilator-associated pneumonia (OR 0.04, CI 95% 0.02-0.13, P<0.001), suspected aspiration (OR 0.20, CI 95% 0.04-0.92, P=0.04), in one regional (OR 0.26, CI95% 0.07-0.97, P=0.05) and one tertiary hospital (OR 0.14, CI 95% 0.03-0. 73, P=0.02) but were more commonly used in older patients (OR 1.02, CI 95% 1.01-1.03, P=0.01). There is practice variability in bronchoscopy and antibiotic use for pneumonia in Australian and New Zealand ICUs without significant impact on patient outcome, as the prevalence of inappropriate antibiotic prescription is low. There are opportunities for improving microbiological diagnostic work-up for isolation of aetiological pathogens.

Adolescent↗
PubMed2005

Disease risk and mortality prediction in intensive care patients with pneumonia. Australian and New Zealand practice in intensive care (ANZPIC II).

This study of ventilated patients investigated pneumonia risk factors and outcome predictors in 476 episodes of pneumonia (48% community-acquired pneumonia, 24% hospital-acquired pneumonia, 28% ventilator-associated pneumonia) using a prospective survey in 14 intensive care units within Australia and New Zealand. For community acquired pneumonia, mortality increased with immunosuppression (OR 5.32, CI 95% 1.58-1799, P<0.01), clinical signs of consolidation (OR 2.43, CI 95% 1.09-5.44, P=0.03) and Sepsis-Related Organ Failure Assessment (SOFA) scores (OR 1.19, CI 95% 1.08-1.30, P<0.001) but improved if appropriate antibiotic changes were made within three days of intensive care unit admission (OR 0.42, CI 95% 0.20-0.86, P=0.02). For hospital-acquired pneumonia, immunosuppression (OR 6.98, CI 95% 1.16-42.2, P=0.03) and non-metastatic cancer (OR 3.78, CI 95% 1.20-11.93, P=0.02) were the principal mortality predictors. Alcoholism (OR 7.80, CI 95% 1.20-17.50, P<0.001), high SOFA scores (OR 1.44, CI 95% 1.20-1.75, P=0.001) and the isolation of "high risk" organisms including Pseudomonas aeruginosa, Acinetobacter spp, Stenotrophomonas spp and methicillin resistant Staphylococcus aureus (OR 4.79, CI 95% 1.43-16.03, P=0.01), were associated with increased mortality in ventilator-associated pneumonia. The use of non-invasive ventilation was independently protective against mortality for patients with community-acquired and hospital-acquired pneumonia (OR 0.35, CI 95% 0.18-0.68, P=0.002). Mortality was similar for patients requiring both invasive and non-invasive ventilation and non-invasive ventilation alone (21% compared with 20% respectively, P=0.56). Pneumonia risks and mortality predictors in Australian and New Zealand ICUs vary with pneumonia type. A history of alcoholism is a major risk factor for mortality in ventilator-associated pneumonia, greater in magnitude than the mortality effect of immunosuppression in hospital-acquired pneumonia or community-acquired pneumonia. Non-invasive ventilation is associated with reduced ICU mortality. Clinical signs of consolidation worsen, while rationalising antibiotic therapy within three days of ICU admission improves mortality for community-acquired pneumonia patients.

Adolescent↗
PubMed2005

Predictors of physician confidence to diagnose pneumonia and determine illness severity in ventilated patients. Australian and New Zealand practice in intensive care (ANZPIC II).

The manner in which elements of clinical history, physical examination and investigations influence subjectively assessed illness severity and outcome prediction is poorly understood. This study investigates the relationship between clinician and objectively assessed illness severity and the factors influencing clinician's diagnostic confidence and illness severity rating for ventilated patients with suspected pneumonia in the intensive care unit (ICU). A prospective study of fourteen ICUs included all ventilated admissions with a clinical diagnosis of pneumonia. Data collection included pneumonia type - community-acquired (CAP), hospital-acquired (HAP) and ventilator-associated (VAP), clinician determined illness severity (CDIS), diagnostic methods, clinical diagnostic confidence (CDC), microbiological isolates and antibiotic use. For 476 episodes of pneumonia (48% CAP, 24% HAP, 28% VAP), CDC was greatest for CAP (64% CAP, 50% HAP and 49% VAP, P<0.01) or when pneumonia was considered "life-threatening" (84% high CDC, 13% medium CDC and 3% low CDC, P<0. 001). "Life-threatening" pneumonia was predicted by worsening gas exchange (OR 4.8, CI 95% 2.3-10.2, P<0.001), clinical signs of consolidation (OR 2.0, CI 95% 1.2-3.2, P<0.01) and the Sepsis-Related Organ Failure Assessment (SOFA) Score (OR 1.1, CI 95% 1.1-1.2, P<0.001). Diagnostic confidence increased with CDIS (OR 16.3, CI 95% 8.4-31.4, P<0.001), definite pathogen isolation (OR 3.3, CI 95% 2.0-5.6) and clinical signs of consolidation (OR 2.1, CI 95% 1.3-3.3, P=0.001). Although the CDIS, SOFA Score and the Simplified Acute Physiologic Score (SAPS II) were all associated with mortality, the SAPS II Score was the best predictor of mortality (P = 0. 02). Diagnostic confidence for pneumonia is moderate but increases with more classical presentations. A small set of clinical parameters influence subjective assessment. Objective assessment using SAPS II Scoring is a better predictor of mortality.

Adolescent↗
PubMed2005

Commercial low-citrate anticoagulation haemofiltration in high risk patients with frequent filter clotting.

This study assessed the safety and efficacy of a commercial low-citrate concentration-based pre-filter replacement fluid during continuous veno-venous haemofiltration (CVVH) in patients with frequent filter clotting and high risk of bleeding. We used a commercial low-citrate fluid as pre-dilution replacement fluid during CVVH (citrate: 11 mmol/l (33 meq/l), sodium: 140 mmol/l, chloride: 108 mmol/l and potassium: 1 mmol/l). A calcium and magnesium infusion was delivered separately by central line for the maintenance of serum ionized calcium (Cai) and total magnesium (Mg). In this prospective observational study, 30 patients, 124 filters and 1,515 treatment-hours were observed. Median filter life of citrate CVVH was 9.5 hours. Filter life in the 48 hours prior to citrate CVVH was also observed. In the patients on prior non-anticoagulant CVVH (n=14) filter life increased significantly with citrate (9.5 hours vs 5 hours; P<0.0001). In patients on prior heparin CVVH (n = 15), filter life was similar with citrate (10 hours vs 8 hours; P = 0.68). However, in patients with prior early/frequent filter clotting despite heparin (n = 11) filter life increased significantly (10 hours vs 7 hours; P=0.038). Of 411 serum Cai measurements, none showed a Cai < 0.85 mmol/l and, of 84 observations, none showed a serum Mg<0. 6 mmol/l. One patient with sepsis and shock needed to cease citrate CVVH because of progressive ionized hypocalcaemia and increasing anion gap. No other adverse effects were observed. In selected patients, CVVH with a commercial low-citrate concentration solution as pre-filter replacement fluid and a simultaneous calcium and magnesium infusion protocol appears generally safe. Filter life was acceptable and superior to that achieved with previous treatment.

Acute Kidney Injury↗
PubMed2005

A technique for the measurement of renal ATP in a large animal model of septic shock.

BACKGROUND: The mechanisms responsible for acute renal failure in sepsis are not understood. Measurement of tissue ATP might help to understand this process but, in the large animal, it is hampered by major technical difficulties. OBJECTIVE: To develop a technique to monitor ATP in the kidney of a large mammal during the induction of septic shock and then circulatory arrest. METHODS: Implantation of a custom-made phosphorus coil around the left kidney. Induction of septic shock by intravenous E. coli administration. Acquisition of 31 P magnetic resonance (MR) spectroscopic data at 3-tesla before and during septic shock over several hours. Induction of euthanasia and measurement of the same 31 P signal immediately and thirty minutes after circulatory arrest. RESULTS: Clear reproducible 31 P MR spectra were obtained before and after the induction of septic shock and euthanasia. They indicated limited changes in ATP during septic shock. An expected rapid and dramatic decrease in ATP occurred with euthanasia. CONCLUSIONS: It is possible to sequentially monitor renal bioenergetics in a large mammal during septic shock using an implanted custom-made phosphorus coil and 3-tesla MR technology. This technique offers a novel approach to the investigation of septic renal failure.

Acute Kidney Injury↗
PubMed2005

Low-dose citrate continuous veno-venous hemofiltration (CVVH) and acid-base balance.

OBJECTIVE: To evaluate the acid-base effect of low-dose regional citrate anticoagulation (RCA) during continuous veno-venous hemofiltration (CVVH). DESIGN: Prospective observational study. SETTING: ICUs of tertiary public and private hospitals. SUBJECTS: Thirty critically ill patients with acute renal failure at risk of bleeding or with a major contraindication to heparin-CVVH and/or short filter life. METHODS: We used a commercial citrate-based fluid (11 mmol/L, sodium: 140 mmol/L, chloride: 108 mmol/L and 1 mol/L of potassium) as pre-dilution replacement fluid during CVVH. Further potassium was added according to serum potassium levels. We measured all relevant variables for acid-base analysis according to the Stewart-Figge methodology. RESULTS: Before treatment, study patients had a slight metabolic acidosis, which worsened over 6 hours of RCA-CVVH (pH from 7.39 to 7.38, p < 0.005; bicarbonate from 23.2 to 21.6 mmol/L, p < 0.0001 and base excess from -2.0 to -3.0 mEq/L, p < 0.0001) due to a significant increase in SIG (from 5.8 to 6.6 mEq/L, p < 0.05) and a decrease in SIDa (from 37.5 to 36.6 mEq/L, p < 0.05). These acidifying effects were attenuated by hypoalbuminemia and a decrease in lactate (from 1.48 to 1.34 mmol/L, p < 0.005) and did not lead to progressive acidosis. On cessation of treatment, this acidifying effect rapidly self-corrected within six hours. CONCLUSIONS: Low dose RCA-CVVH induces a mild acidosis secondary to an increased strong ion gap and decreased SIDa which fully self-corrects at cessation of therapy. Clinicians need to be aware of these effects to correctly interpret changes in acid-base status in such patients.

Acid-Base Equilibrium↗