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<0.6mmol/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.

Resistance of vascular access catheters for continuous renal replacement therapy: An ex vivo evaluation

Aim

To assess the resistance posed by double-lumen vascular access dialysis catheters at low and high blood flow.

Design

Controlled ex vivo study

Setting

ICU Laboratory of tertiary hospital.

Subjects

Eleven proprietary vascular access catheters for continuous renal replacement therapy. Methods: Heparinized spent red cells diluted in polygeline solution were pumped using the Aquarius hemofiltration machine (Edwards Life Sciences, Sydney, NSW, Australia) and its standard circuit through several vascular access catheters. Blood flow was increased and then decreased in steps of 50 ml/min (50, 150, 200, 250 and 300 ml/min) while catheter outflow and inflow pressures were recorded. The pressure-flow relationship (hydraulic resistance) of each catheter was then calculated. Study catheters were divided into two groups according to their internal diameter (large gauge vs. smaller gauge) or length (long or short). Hydraulic resistances were compared between the groups. Results: Different double lumen catheters posed clearly different resistances to flow. For all groups of catheters, there was a linear relationship between pressure and flow. No statistically significant difference between short and long catheters could be demonstrated (p=0.715). On the other hand, larger gauge catheters (13 Fr or greater) had significantly lower resistances than smaller gauge (<13 Fr) catheters (p=0.0062). Furthermore, all larger gauge catheters had resistances lower than 0.430 mmHg/ml/min, while all smaller gauge catheters had resistances greater than 0.490 mmHg/ml/min. Conclusions: Commercial double-lumen dialysis catheters have variable resistance to blood flow under standard ex vivo conditions. Although both length and internal diameter varied, internal diameter had a dominant effect on resistance. This information might be useful to clinicians in guiding their choice of catheters for clinical use. (Int J Artif Organs 2008; 31: 905–9)

Super High Flux Hemodialysis at High Dialysate Flows: An Ex Vivo Assessment

Background and objectives

The removal of cytokines by standard hemofiltration is limited. Super high flux membranes may significantly improve removal even when used in dialysis mode. We sought to measure cytokine clearance using a large surface super high-flux membrane and a standard hemodialysis setting.

Setting

ICU laboratory of a tertiary institution.

Subjects

Six healthy volunteers.

Methods

Blood form healthy volunteers was incubated for 4 hours with E. coli endotoxin to stimulate cytokine production. Cytokine containing blood was then circulated through a dialysis circuit at 3 different dialysate flow rates. Blood and dialysate were sampled for cytokine and albumin measurements and calculation of clearances.

Results

Super high-flux dialysis achieved high median cytokine clearances (IL-1 clearance of 106 ml/min, IL-6 clearance of 66.8 ml/min, IL-8 clearance of 61.7 ml/min and TNF clearance of 36.1 ml/min). Increasing dialysate flow rate from 300 to 500 ml/min did not significantly increase cytokine clearances. Albumin clearances however were between 2.7 and 5.4 ml/min.

Conclusions

Cytokine dialysis is feasible at high dialysate flow rates yielding high cytokine clearances. Albumin loss, however, is appreciable and may require separate supplementation in the clinical setting.

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.

High Cut-off Point Membranes in Septic Acute Renal Failure: A Systematic Review

Objectives

To review the literature on the experimental, physiological and clinical effects of blood purification with high cut-off (HCO) point membranes in septic acute renal failure (ARF).

Study Design

MEDLINE and PubMed database search combining relevant terms and integrating data from studies on the use of HCO membranes.

Setting and Population

Ex vivo studies of endotoxemia, animal studies of bacteremia and clinical studies using HCO membranes in patients with septic ARF. Selection Criteria for Studies: Original data from primary publications. Interventions: HCO membrane-based hemodialysis, hemodiafiltration or hemofiltration. Outcomes: Plasma cytokine clearance, immunological and physiological effects and safety parameters of HCO membranes.

Results

HCO membranes effectively remove cytokines from blood. Treatment using HCO membranes has beneficial effects on immune cell function and increases survival in animal models of sepsis. Preliminary clinical studies show that HCO membranes decrease plasma cytokine levels and the need for vasopressor therapy. HCO membrane-based blood purification has now been applied in four pilot randomized controlled studies of 70 patients with septic ARF with no reports of serious adverse effects.

Limitations

Because of substantial heterogeneity, no formal quantitative analysis could be performed.

Conclusions

The available evidence on HCO blood purification justifies larger randomized controlled trials in patients with septic ARF.

The Effect of Three Different Miniaturized Blood Purification Devices on Plasma Cytokine Concentration in an Ex Vivo Model of Endotoxinemia

Purpose

A novel type of adsorptive plasma filtering device (ETX-A) capable of removing endotoxin from blood in a single step has recently been developed using nanotechnology.

Methods

In a miniaturized, ex vivo model of extracorporeal circuits, we tested the capacity to reduce plasma cytokine concentration of ETX-A filters in comparison to standard high-flux (HF) filters, high cut-off (HCO) filters and a control. Blood from six healthy volunteers was spiked with endotoxin and then circulated through closed (ETX-A, control) or open (HF, HCO) circuits. Blood flow was set at 16 ml/min and filtration flow at 1 ml/min. Samples for measurement of IL-1ra and IL-6 were taken at baseline and at 4 hours.

Results

Compared to control (703.3 [850.6] pg/mL), in HCO (383.5 [1144.1] pg/mL) and ETX-A (490.1 [683.2] pg/mL) filters, plasma IL-1ra pooled pre- and postfilter concentrations were lower at the end of the experiment (P=0.002; P=0.050, respectively) whereas, in standard HF filters, IL-1ra concentration was higher than control. HCO showed a trend toward a reduced relative increase in IL-6 concentration from commencement to end of experiment compared to control (P=0.07). After pooling end-of-experiment plasma cytokine values of novel blood purification devices, we found HCO + ETX-A superior to H with regard to reduction of IL-1ra (-27.0 [−20.5]% vs. 8.1 [18.9]%; P<01) and IL-6 (-18.0 [38.3]% vs. −1.1 [24.3]%; P=0.050) compared to control.

Conclusions

HCO and ETX-A appeared to significantly reduce plasma IL-1ra and, when combined, plasma IL-6 concentration as well. It appears desirable to manufacture full-size blood purification devices using this technology and to explore their effect on cytokine removal.

Fluid Balance Error in Continuous Renal Replacement Therapy: A Technical Note

Background.

The reliability and safety of continuous renal replacement therapy (CRRT) machines have improved, yet there still remains the potential for fluid balance errors to occur during treatment.

Methods.

In vitro testing of two Kimal Hygieia CRRT machines (Plus and Ultima) was performed. Normal saline to simulate the blood circuit and standard bicarbonate-based fluid for replacement were used. All tests were performed in CVVH mode at four ultrafiltration (UF) rates. The testing was based on creation of a voluntary fluid balance error by clamping the line that fills the replacement fluid chamber to stop flow to the (simulated) patient. The time to alarms and fluid balance errors were recorded. The alarms were overridden and the accumulated fluid balance error allowed by the machine was determined.

Results.

The alarm occurred approximately 1 minute after the replacement fluid line was clamped at all UF rates. There was no limit to the number of times the alarm could be overridden and the accumulated negative fluid balance was proportional to the prescribed UF rate. After the replacement fluid chamber was allowed to re-fill, the machine attempted to correct the fluid deficit and consistently delivered excess fluid to generate a positive fluid balance error.

Conclusions.

The Hygieia machines appear designed with appropriate alarm and safety features. However, simulated fluid balance errors raise caution for operators. Clinicians and nurses need to understand the clinical implications of alarm overrides. Fluid balance errors caused by failure to acknowledge and correct replacement fluid failure alarms may cause harm to patients.

Prolonged Daily Intermittent Renal Replacement Therapy in ICU Patients by ICU Nurses and ICU Physicians

Objectives

Prolonged daily intermittent renal replacement therapy (PDIRRT) has been proposed as a new form of treatment for severe acute renal failure (ARF). However, this treatment has so far implied a) full dependence on nephrological input, b) lack of any convective clearance and c) limited purification of dialysate water. The aim of this study was to establish the feasibility and safety of performing PDIRRT in the ICU with a) no nephrological input, b) the addition of some convective clearance with on-line fluid replacement and c) a new advanced water purification system.

Design

Prospective observational study.

Patients

Fourteen patients treated with PDIRRT.

Setting

ICU of tertiary institution.

Interventions

Treatment of patients with severe ARF and critical illness with PDIRRT. Prescription of treatment by ICU physicians. Conduct of treatment by ICU nurses. Use of combined convective and diffusive therapy with on-line generation of fluid replacement, application of a double-filtration water purification system.

Measurements and Main Results

We prospectively collected demographic, biochemical, hemodynamic and clinical data in 14 patients, who received 30 PDIRRT treatments for a cumulative treatment time of 205.4 hours. The mean age was 57.9 ± 16.0. Eight patients were male and 6 female. Their mean APACHE II score was 24.6 ± 5.9 and their SAPS II score was 41.7 ± 18.8. PDIRRT was used after at least 24 hours of initial stabilization with continuous veno-venous hemofiltration (CVVH). Blood flow was kept at 100ml/min dialysate flow at 200 ml/min and convective clearance varied from 21 ml/min to 33 ml/min. All patients were either anuric or oliguric (UO < 400 ml/day). Ten patients were on mechanical ventilation and 11 patients on vasopressor support. Mean treatment session time was 6.9 ± 1.8 hours. The mean pre-PDIRRT urea was 19.2 ± 6.9 mmol/L and the creatinine was 274 ± 116 μmol/L. The mean pre-PDIRRT lactate was 2.95 ± 2.24 mmol/L. Following treatment, all had significantly decreased to 13.2 ± 6.3 mmol/L, 215 ± 95 μmol/L and 2.25 ± 1.61 mmol/L, respectively (p=<0.0001, <0.0001, <0.05). Bicarbonate levels remained stable during treatment (23.0 ± 3.8 mmol/L to 23.1 ± 2.5 mmol/L). Mean norepinephrine dose changed from 8.8 ± 11.9 μg/min to 12.9 ± 27.0 μg/min after treatment (NS). There were no complications of therapy. Patient ICU survival was 71.4%.

Conclusions

PDIRRT with combined diffusive and convective clearance is an efficacious form of renal replacement, which can be safely and effectively conducted by ICU nurses following prescription by ICU physicians without any nephrological involvement and with adequate double filtration water purification.

Role of Technology for the Management of AKI in Critically Ill Patients: From Adoptive Technology to Precision Continuous Renal Replacement Therapy

This paper reports on the continuous renal replacement therapy (CRRT) technology group recommendations and research proposals developed during the 17th Acute Dialysis Quality Initiative Meeting in Asiago, Italy. The group was tasked to address questions related to the impact of technology on acute kidney injury management. We discuss technological aspects of the decision to initiate CRRT and the components of the treatment prescription and delivery, the integration of information technology (IT) on overall patient management, the incorporation of CRRT into other 'non-renal' extracorporeal technologies such as ECMO and ECCO2R and the use of sorbents in sepsis and propose new areas for future research. Instead of reviewing current knowledge, the group focused on developing a renovated research agenda that reflects current and future technological advances, centered on innovations in new equipment, membranes and IT that will permit the integration of patient care and decision-making processes for years to come.

Incidence, Risk Factors and Outcome Associations of Intra-Abdominal Hypertension in Critically Ill Patients

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are significantly associated with morbidity and mortality. We performed a prospective observational study and applied recently published consensus criteria to measure and describe the incidence of IAH and ACS, identify risk factors for their development and define their association with outcomes. We studied 100 consecutive patients admitted to our general intensive care unit. We recorded relevant demographic, clinical data and maximal (max) and mean intra-abdominal pressure (IAP). We measured and defined IAH and ACS using consensus guidelines. Of our study patients, 42% (by IAPmax) and 38% (by IAPmean) had IAH. Patients with IAH had greater mean body mass index (30.4±9.6 vs 25.4±5.6 kg/m2, P=0.005), Acute Physiology and Chronic Health Evaluation III score (78.2±28.5 vs 65.5±29.2, P=0.03) and central venous pressure (12.8±4.8 vs 9.2±3.5 mmHg, P <0.001), lower abdominal perfusion pressure (67.6±13.5 vs 79.3±17.3 mmHg, P <0.001) and lower filtration gradient (51.2±14.8 vs 71.6±17.7 mmHg; P <0.001). Risk factors associated with IAH were body mass index ≥30 (P <0.001), higher central venous pressure (P <0.001), presence of abdominal infection (P=0.005) and presence of sepsis on admission (P=0.035). Abdominal compartment syndrome developed in 4% of patients. IAP was not associated with an increased risk of mortality after adjusting for other confounders. We conclude that, in a general population of critically ill patients, using consensus guidelines, IAH was common and significantly associated with obesity and sepsis on admission. In a minority of patients, IAH was associated with abdominal compartment syndrome. In this cohort IAH was not associated with an increased risk of mortality.

The acid-base effect of changing citrate solution for regional anticoagulation during continuous veno-venous hemofiltration

PURPOSE

To compare the acid-base balance effects of two different citrate doses for regional citrate anticoagulant (RCA) for continuous veno-venous hemofiltration (CVVH).

METHODS

We used a commercial citrate fluid (citrate concentration: 11 mmol/L) from July 2003 to July 2004 (period A) in 22 patients; then changed to a new citrate fluid (citrate concentration: 14 mmol/L) from July 2004 to Feb 2005 (Period B) in 21 patients. Replacement fluid rate was fixed at 2,000 ml/h. We measured all relevant variables for acid-base analysis according to the Stewart-Figge methodology.

RESULTS

After commencement of RCA-CVVH, there was a change in bicarbonate and base excess (BE) toward acidosis for both fluids. This change was significantly different between period A and B at 6 and 12 hours (pH: p<0.01, BE: p<0.05) with greater decreases with the 11 mmol/L citrate fluid. These changes were mostly secondary to an increase in the strong ion difference (SID) and occurred despite an increased strong ion gap (SIG) (+0.5 mEq/L vs. +1.5 mEq/L; p<0.01) in the higher citrate concentration fluid. Cessation of RCA-CVVH was associated with short-lived differences in bicarbonate and SIG which were similar to those seen on initiation of RCA-CVVH but in the opposite direction.

CONCLUSIONS

A small increase This was partly offset by an increase in SIG, consistent with increased citratemia. Cessation of treatment showed a differential improvement in SIG also consistent with disposal of therapy-associated citrate. These observations might assist clinicians in interpreting acidbase changes during RCA-CVVH.in citrate infusion rate caused an alkalinizing increase in SID.

A pilot randomized controlled comparison of extended daily dialysis with filtration and continuous veno-venous hemofiltration: fluid removal and hemodynamics

OBJECTIVES

Extended intermittent dialytic techniques are increasingly being reported in the treatment of ARF in the ICU but few randomized controlled trials exist. We compared one such technique to a technique of continuous renal replacement therapy with regard to fluid removal and hemodynamics.

METHODS

Sixteen critically ill patients with ARF were enrolled in a randomized controlled trial at the ICU of a tertiary hospital. We randomized eight patients to three consecutive days of treatment with either Extended Daily Dialysis with filtration (EDDf) or Continuous Veno-Venous Hemofiltration (CVVH) and compared fluid removal and hemodynamics during treatment.

RESULTS

A total of 16.6 liters of fluid were removed during EDDf (830 mL/day over 20 treatment days) compared with 15.4 liters (700 ml/day over 22 treatment days) during CVVH. Median fluid removal per day was 1837 mL in the EDDf group compared with 1410 mL per day in the CVVH group, p=0.674. Median hourly fluid removal rate was 252 mL for EDDf and 128 mL for CVVH (p<0.01). Mean arterial pressure in the EDDf group was lower at two hours after starting treatment (76 mmHg vs. 94 mmHg) in the CVVH group; p= 0.031. There was no significant difference between groups for heart rate, CVP and noradrenaline dose at all time intervals measured.

CONCLUSIONS

Adequate prescribed fluid removal was achieved with both techniques. However, as expected, fluid was removed at a faster rate during EDDf. This was initially associated with a lower blood pressure than during CVVH where blood pressure increased.

Beta2-microglobulin removal and plasma albumin levels with high cut-off hemodialysis

PURPOSE

beta2-microglobulin (beta2MG) is pivotal to the pathogenesis of dialysis-related amyloidosis. We compared the effects of high cut-off hemodialysis (HCO-HD) with those of standard high-flux hemodialysis (HF-HD) regarding the concentration and clearance of beta2MG and albumin.

DESIGN

We enrolled ten patients with acute renal failure in a double-blind, cross-over, randomized controlled trial.

PROCEDURES

Each patient received four hours of HCO-HD (estimated in vivo cutoff 50-60 kDa) and four hours of HF-HD (estimated in vivo cutoff 15-20 kDa) in random order. Statistical methods and outcome measures: As data lacked normal distribution, we used nonparametric statistical analysis. Plasma and dialysate concentrations of beta2MG and albumin were measured at baseline and after four hours of each study treatment.

MAIN FINDINGS

We found significantly greater diffusive beta2MG clearances for HCO-HD compared to HF-HD (at the start: 71.8 ml/min vs. 5.1 ml/min; P=0.008 and at the end: 68.8 ml/min vs. 5.7 ml/min; P=0.008). We found a reduction in plasma beta2MG concentrations of -31.6% during HCO-HD compared to an increase by 25.7% during HF-HD; P=0.008. At baseline (HCO-HD: 26.0 g/L vs. HF-HD: 26.5 g/L), and at the end of both treatments, plasma albumin concentrations were comparable (HCO-HD: 25.5 g/L vs. HF-HD: 26.5 g/L; P=0.25). During HCO-HD, albumin clearance was 1.9 ml/min at the start and decreased significantly to 0.8 ml/min at the end; P=0.008. HF-HD had an albumin clearance of 0.01 ml/min.

CONCLUSIONS

HCO-HD was more effective in decreasing plasma beta2MG concentrations than standard HF-HD and did not reduce plasma albumin levels. Further studies of HCO-HD in the treatment of dialysis-related beta2MG accumulation appear warranted.

A pilot randomized controlled crossover study comparing regional heparinization to regional citrate anticoagulation for continuous venovenous hemofiltration

OBJECTIVE

To evaluate the efficacy and safety of a regional heparinization and a regional citrate method of anticoagulation in CVVH.

DESIGN

Randomized controlled cross-over study.

SUBJECTS

Ten critically ill patients with acute renal failure.

SETTING

ICU of tertiary hospital.

INTERVENTION

CVVH was performed with pre-filter fluid replacement at 2000 ml/h and a blood flow rate of 150 ml/min. Regional heparinization was by the administration of heparin pre-filter at 1500 IU/h and protamine post-filter at 15 mg/h. Regional citrate anticoagulation was by means of a citrate-based replacement fluid (14 mmol/L) administered pre-dilution.

RESULTS

We studied nine males and one female. The mean age and APACHE II score were 70.5 and 17 respectively. Median circuit life was 13 hours (IQR 9.28) for the regional heparinization method compared to 17 hours (IQR 12,19.5) for the regional citrate method (p=0.77). There were no episodes of bleeding in either group.

CONCLUSION

Regional heparinization and regional citrate anticoagulation achieve similar circuit life in critically ill patients receiving CVVH.

Fluid balance error in continuous renal replacement therapy: a technical note

BACKGROUND

The reliability and safety of continuous renal replacement therapy (CRRT) machines have improved, yet there still remains the potential for fluid balance errors to occur during treatment.

METHODS

In vitro testing of two Kimal Hygieia CRRT machines (Plus and Ultima) was performed. Normal saline to simulate the blood circuit and standard bicarbonate-based fluid for replacement were used. All tests were performed in CVVH mode at four ultrafiltration (UF) rates. The testing was based on creation of a voluntary fluid balance error by clamping the line that fills the replacement fluid chamber to stop flow to the (simulated) patient. The time to alarms and fluid balance errors were recorded. The alarms were overridden and the accumulated fluid balance error allowed by the machine was determined.

RESULTS

The alarm occurred approximately 1 minute after the replacement fluid line was clamped at all UF rates. There was no limit to the number of times the alarm could be overridden and the accumulated negative fluid balance was proportional to the prescribed UF rate. After the replacement fluid chamber was allowed to re-fill, the machine attempted to correct the fluid deficit and consistently delivered excess fluid to generate a positive fluid balance error.

CONCLUSIONS

The Hygieia machines appear designed with appropriate alarm and safety features. However, simulated fluid balance errors raise caution for operators. Clinicians and nurses need to understand the clinical implications of alarm overrides. Fluid balance errors caused by failure to acknowledge and correct replacement fluid failure alarms may cause harm to patients.

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.

A comparison of two citrate anticoagulation regimens for continuous veno-venous hemofiltration

AIMS

To assess the safety and efficacy of two different commercial citrate containing pre-filter replacement fluids during continuous veno-venous hemofiltration (CVVH) in patients with frequent filter clotting.

SETTING

Four intensive care units.

PATIENTS

Sixty-three critically ill patients with acute renal failure (ARF).

DESIGN

Prospective observational study.

METHODS

We used a commercial citrate fluid (citrate: 11 mmol/L -fluid A) as predilution replacement for CVVH. We then changed to a new commercial citrate fluid (citrate: 14 mmol/L-fluid B) as replacement fluid and performed statistical comparisons. Replacement fluid rate was fixed at 2,000 ml/hour.

RESULTS

Filter life was 12.2 hour with fluid A compared with 17.1 hour with fluid B on average (p=0.0001). Mean post filter ionized calcium concentration was 0.52 mmol/L with fluid A compared with 0.40 mmol/L with fluid B (p<0.0001). Citrate intolerance led to cessation of treatment in one patient with fluid A and one patient with fluid B. Overall ionized calcium levels were higher (A: 1.18 vs B: 1.13 mmol/L; p<0.0001) and bicarbonate was lower (A: 22.4 vs B: 24.5 mmol/L; p<0.0001) during treatment with fluid A. Alkalemia was seen in 10 patients treated with fluid A and 16 patients treated with fluid B (NS).

CONCLUSIONS

We have developed a simple approach to regional citrate anticoagulation for CVVH using a commercial citrate-containing fluid as replacement fluid. Increasing citrate concentration from 11 to 14 mmol/L increased filter life while maintaining relative safety and simplicity.

Management of fluid balance in CRRT: a technical approach

BACKGROUND

The possibility of making fluid balance errors during continuous renal replacement therapy has been identified since the beginning of this modality of treatment. The advent of automated machines has partially overcome this problem. Nevertheless, there are conditions and operation modes in which the potential for fluid balance errors is still present.

OBJECTIVE

To analyse fluid balance management in CRRT therapies across a range of currently marketed machine.

METHODS

The tests were conducted in vitro, utilizing saline solution for the blood circuit and regular dialysate/reinfusate for the dialysate/reinfusion circuit. The methodology used was based on the voluntary creation of a fluid balance error by altering the correct flow in the circuit of the different machines. Subsequently, the time for alarm occurrence and the threshold value for fluid balance error was evaluated. The alarm was overridden and the overall fluid error allowed by the machine was evaluated. Each machine was tested in conditions of different dialysate/filtrate flow rates and in different simulated treatment modalities.

RESULTS

Fluid balance errors can be easily avoided not only by a correct and careful adherence to the protocols of use of the current CRRT machines, but also by the compliance to prescriptions and programmed controls during therapy. Most importantly, if an alarm appears on the machine, one can try to override it without major problems; major problems may occur when multiple override commands are operated without identifying the problem and solving it adequately.

CONCLUSION

Machines seem to be designed with adequate safety features and accurate alarm systems. However, features and alarms can be manipulated by operators creating the opportunity for serious error. Physicians and nurses involved in prescription and delivery of CRRT should have precise protocols and defined procedures in relation to machine alarms to prevent major clinical problems.

[Long-term intermittent renal replacement therapy at an intensive care unit]

Standard intermittent hemodialysis (IHD) used for the treatment of acute renal failure (ARF) at an intensive care unit has significant biochemical and physiological drawbacks. In the past 20 years, these drawbacks have stimulated the development of continuous renal replacement therapy (CRRT) and its ever-increasing use. However, CRRT is technically complicated and requires 24-hour monitoring. In some clinics, the use of CRRT leads to that each patient is under his/her nurse's surveillance, instead 1 nurse per 2 patients as before; this change has economic consequences and may limit nursing accessibility to other patients. The procedures prolonging intermittent therapy do not require 24-hour monitoring may benefit the treatment of ARF at the intensive care therapy. In this paper the authors call such procedures for continuous intermittent renal replacement therapy. They are characterized by a number of basic principles: (1) the use of modified or standard dialysis apparatuses; (2) the application of diffuse, convection, or both; (3) a certain reduction in the rate of elimination of dissolved substances as compared with IHD; (4) more prolonged treatment: above usual 3 or 4 hours of IHD, but not more than 8-12 hours (hence the term "intermittent"); (5) the use of on-line generation dialysate or substituting fluid. Information on the effectiveness and safety of this procedure is being now compiled.

A pilot study of the effect of altering airway pressure on systolic pulse pressure variation in the systemic and pulmonary arterial circulations

OBJECTIVE

Systolic pressure variation results from cyclical fluctuation in the intra-thoracic pressure associated with mechanical ventilation and has been used as a measure of relative hypovolemia in mechanically ventilated patients. The impact of the magnitude of the tidal volume and airway pressure on systolic pressure variation, however, has not been examined in mechanically ventilated patients.

METHODS

Two patients underwent monitoring following elective cardiac surgery. Tidal volume was randomly varied between 3 and 11 mL/kg over a two minute interval, and the corresponding airway pressure was monitored, as were the effects on the systolic pressure variation of the systemic and pulmonary circulations.

RESULTS

There was a strong correlation between increasing tidal volume and peak airway pressure (p<0.0001). In addition, peak airway pressure strongly correlated with the systolic pressure variation of both the systemic and pulmonary circulations (p<0.0001). The increase in diastolic pulmonary arterial pressure induced by insufflation correlated well with the associated increase in systolic blood pressure (p<0.0001). Similarly, the increase in systolic pulmonary artery pressure (PAP) correlated with the associated decrease in systolic blood pressure induced by insufflation (p<0.0001).

CONCLUSIONS

Systolic pressure variation in the systemic and pulmonary circulations is affected by tidal volume and peak airway pressure. This should be considered when using systolic pressure variation as a marker of intravascular volume status. Our findings regarding the correlations between changes in the pulmonary arterial pressure and the systemic arterial pressure induced by mechanical ventilation are consistent with the proposed physiological mechanisms of systolic pressure variation.

A technique for the determination of systolic pressure variation in the systemic and pulmonary arterial circulations

INTRODUCTION

Systolic pressure variation has previously been used to detect the presence of hypovolemia in mechanically ventilated patients but remains difficult to measure.

METHODS

We describe the application of a commercially available physiological data acquisition system, PowerLab (ADI Instruments Castle Hill, NSW, Australia), to acquire and graphically display simultaneous recordings of the airway pressure, as well as systemic and pulmonary arterial pressures. The technique involves the use of standard pressure transducers to record each pressure reading and has been used to obtain measurements in patients undergoing elective cardiac surgery.

RESULTS

The technique permits calculation of systolic pressure variation of both the systemic and pulmonary arterial pressure waveforms. In addition it is possible to estimate plateau airway pressure and perform expiratory hold maneuvers to determine its constitutive components delta-up and delta-down. Waveforms can be exported into MS-windows Paint and saved in JPEG or bitmap format.

CONCLUSIONS

The technique described will permit future analysis of the factors affecting the systolic pressure variation for the systemic and pulmonary arterial pressure waveforms in the clinical context.

Beta2-microglobulin clearance with super high flux hemodialysis: an ex vivo study

BACKGROUND

Beta2m accumulation induces disease in patients with end-stage renal failure (ESRF). Thus, its removal from patients with ESRF appears desirable. Current dialysis technology, however, has limited effectiveness.

AIMS

To measure beta2m clearance with a novel super high flux membrane.

DESIGN

Ex vivo experimental study.

SETTING

Intensive Care Laboratory of Tertiary institution.

SUBJECTS

Six volunteers.

MEASUREMENTS AND RESULTS

At a blood flow of 300 ml/min, the clearance of beta2-MG increased from 113.5 +/- 38.5 ml/min with a dialysate flow rate of 200 ml/min to 184.8 +/- 61.1 ml/min with a flow rate of 300 ml/min and 195.0 +/- 60.0 ml/min with a 500 ml/min flow rate. The clearance of albumin was 4.5 ml/min with a dialysate flow rate of 200 ml/min, 5.2 ml/min for a flow rate of 300 ml/min and 5.8 ml/min for a flow rate of 500 ml/min.

CONCLUSIONS

High levels of beta2m clearance can be achieved with a super high flux membrane while albumin losses remain limited.

Prolonged intermittent renal replacement therapy in the intensive care unit

OBJECTIVE

To present a review on the use of prolonged intermittent renal replacement therapy in the intensive care patient.

DATA SOURCES

Articles and abstracts reporting the use of renal replacement therapy.

SUMMARY OF REVIEW

Standard intermittent haemodialysis (IHD) has significant shortcomings in the treatment of the acute renal failure (ARF) of critical illness. These shortcomings include haemodynamic instability, the need to remove excess fluid over a short period of time, the episodic nature of small solute control, the limited ability to achieve middle molecular weight solute control and the episodic nature of acid-base control. Over the last 20 years, these limitations have stimulated the evolution and increased application of continuous renal replacement therapy (CRRT) which provides major biochemical, biological and physiological advantages compared with IHD, although it remains unclear as to whether such advantages translate into a survival advantage. However, CRRT is technically demanding, requires supervision 24 hr per day and is often associated with the need for continuous anticoagulation, which, in some patients, might be undesirable. In some institutions, CRRT changes the nurse to patient ratio from 1:2 to 1:1, an alteration which has cost implications and might affect resource availability for other patients. Accordingly, techniques which prolong the duration of intermittent therapy and avoid the need for 24 hr treatment may offer "best value" in the management of ARF in the intensive care unit (ICU). These techniques will be referred to as prolonged intermittent renal replacement therapies (PIRRT) in this article. They are characterised by several fundamental principles: 1. Use of a modified or standard dialysis machines, 2. Use of diffusion, convection or any combination of the two, 3. Application of a decreased intensity of solute removal compared with IHD, 4. Extended duration of treatment beyond the typical 3 or 4 hr of standard IHD (hence the term prolonged) but not beyond an 8-12 hr period (hence the term intermittent) and 5. Use of "on-line" generation of dialysate or replacement fluid from tap water.

CONCLUSIONS

Information is now being obtained on the efficacy and safety of PIRRT in the ICU. Several units in Australia have started applying this technology to patient care. It is now important that critical care physicians and nurses become familiar with its principles and practice.

The effect of circuit "down-time" on uraemic control during continuous veno-venous haemofiltration

OBJECTIVE

The term continuous veno-venous haemofiltration (CVVH) suggests a treatment without interruption. However, interruptions do occur and the duration of the haemofiltration circuit "down-time" may influence uraemic control. We conducted a prospective study to ascertain the percentage of operative "down-time" for CVVH in our intensive care unit and to test the hypothesis that it significantly affected uraemic control.

PATIENTS AND METHODS

Prospective data measuring the time spent off the filter in ten patients receiving CVVH were collected. Continuous veno-venous haemofiltration was performed at 2 litres per hour of ultrafiltration. Anticoagulation was maintained using unfractionated heparin administered pre-filter and infused at a rate to achieve a systemic APTT varying between 30-45 seconds. The circuit functional life was documented for each CVVH circuit as progressive cumulative hours of operation. The time off treatment was calculated for each 24-hour period. These data were then correlated with the change in plasma urea and creatinine concentrations for each 24-hour cycle. The APTT, INR, haemoglobin and platelet count were measured and levels were correlated with the filter duration.

RESULTS

Ninety three days of CVVH treatment were assessed in 4 female and 6 male patients. The mean circuit "down-time" in these patients for this period was 22% or 5.27 hours per day. The most common cause of circuit "down-time" was circuit clotting, followed by a need for radiological procedures, time spent in the operating theatre and catheter malfunction requiring replacement. There was a strong correlation between circuit "down-time" and increase in plasma urea (p = 0.0017) and creatinine (p = 0.0451) concentrations. Circuit "down-time" was also inversely correlated with the platelet count (p = 0.0048) but not significantly correlated with the APTT, INR or haemoglobin values.

CONCLUSIONS

In our study the average daily duration of an interruption in CVVH (i.e. circuit "down-time") represented > 20% of the potential operative time. There was a strong correlation between time without treatment and solute control during CVVH. The percentage of "down-time" may be a useful marker of operative quality during CVVH.

Super high flux hemofiltration: a new technique for cytokine removal

OBJECTIVE

To test whether hemofiltration using a hemofilter with large pores (super high flux hemofiltration) achieves effective cytokine removal.

DESIGN

: Ex vivo study.

SETTING

Laboratory of an intensive care unit in a tertiary hospital.

PATIENTS AND PARTICIPANTS

Five healthy volunteers.

INTERVENTIONS

Blood was spiked with 1 mg of endotoxin and then circulated through a closed hemofiltration circuit with a large pore polyamide super high flux hemofilter (nominal cut-off point: 100 kDa). Hemofiltration was conducted at 1 l/h or 6 l/h of ultrafiltrate flow. Samples were taken from the arterial, venous and ultrafiltration sampling ports.

MEASUREMENTS AND RESULTS

Sieving coefficients (SC) above 0.6 were achieved for interleukin (IL)-1beta, IL-6 and IL-10 and SCs above 0.3 were achieved for IL-8 and TNF-alpha at 1 l/h. SCs of all cytokines (except IL-1) were reduced when the ultrafiltration rate was increased from 1 l/h to 6 l/h ( p<0.01), but cytokine clearances still increased ( p<0.01). The highest SC for albumin was 0.1 at 1 l/h and fell to 0.01 at 6 l/h. No adsorption of cytokines and albumin was observed.

CONCLUSION

High volume ultrafiltration using a super high flux filter achieved cytokine clearances comparable to, or greater than, those currently achieved for urea during standard continuous renal replacement therapy.

Cytokine removal with a large pore cellulose triacetate filter: an ex vivo study

OBJECTIVE

To test the hypothesis that hemofiltration using a new large pore cellulose triacetate hemofilter can achieve effective ultrafiltration of cytokines.

DESIGN

Ex-vivo study.

SETTING

Laboratory of Intensive Care Unit in tertiary hospital.

SUBJECTS

Six healthy volunteers.

INTERVENTIONS

Blood from 6 volunteers was incubated for 4 hours with 1 mg of endotoxin and then circulated through a closed hemofiltration circuit with a large pore cellulose triacetate hemofilter (nominal cut-off point: 60 kilodaltons). Hemofiltration was conducted at 1 L/h or 6 L/h of ultrafiltrate (UF) flow at the start of extra-corporeal circulation, and after 2 and 4 hours. Samples were taken from the arterial, venous and UF sampling ports.

MEASUREMENTS AND MAIN RESULTS

IL-Ibeta, IL-6, IL-8, IL-10, TNFalpha, and albumin were measured. Sieving coefficients (SC) above 0.6 were achieved for IL-Ibeta and IL-6 and SCs above 0.3 were achieved for IL-8 and TNF-alpha at 1 L/h. Sieving coefficients of all cytokines (except IL-10, p=0.22) were reduced when the ultrafiltration rate was increased from IL/h to 6 L/h (p<0.01), but the increase in ultrafiltration rate resulted in an overall increase in the clearance of all cytokines (p<0.001). The highest SC for albumin was 0.07 at 4 hours at 1 L/h, and fell to 0.01 at 6 L/h. The SCs for IL-8 fell at 4 hours (p<0.01), but the SCs for other cytokines did not change. No adsorption of cytokines and albumin was observed.

CONCLUSION

High volume hemofiltration (HVHF) using a new large pore cellulose triacetate filter achieved cytokine clearances greater than those reported with currently available hemo filters.

Extracorporeal blood purification therapy for sepsis and systemic inflammation: its biological rationale

EBPTs represent a promising new approach to the adjuvant treatment of severe sepsis, septic shock and MODS. Their technology is rapidly evolving and pilot animal and human studies are now taking place to prepare the territory for the first large randomized controlled trial. The rationale for EBPT is reasonable and the initial data are encouraging. The correct technology and molecular targeting, however, are still being explored. Once the best technology has been determined, it is likely that phase II and phase III trials will be performed to test the hypothesis that these therapies can indeed alter mortality in severe inflammatory multiorgan dysfunction.

High-volume haemofiltration in human septic shock

OBJECTIVE

To evaluate whether high volume haemofiltration improves haemodynamics and affects serum cytokine and complement concentrations in human septic shock.

DESIGN AND SETTING

Randomized cross-over clinical trial in a tertiary intensive care unit.

PATIENTS

Eleven patients with septic shock and multi-organ failure.

INTERVENTIONS

Patients were assigned to either 8 h of high-volume haemofiltration (HVHF; 6 l/h) or 8 h of standard continuous veno-venous haemofiltration (CVVH; 1 l/h) in random order.

MEASUREMENTS AND MAIN RESULTS

We measured changes in haemodynamic variables, dose of norepinephrine required to maintain a mean arterial pressure greater than 70 mmHg and plasma concentrations of complement anaphylatoxins and several cytokines. An 8-h period of HVHF was associated with a greater reduction in norepinephrine requirements than a similar period of CVVH (median reduction: 10.5 vs. 1.0 microg/min; p = 0.01; median percentage reduction: 68 vs. 7%; p = 0.02). Both therapies were associated with a temporary reduction (p < 0.01) in the plasma concentration of C3a, C5a, and interleukin 10 within 2 h of initiation. HVHF was associated with a greater reduction in the area under the curve for C3a and C5a (p < 0.01). The concentration of the measured soluble mediators in the ultrafiltrate was negligible.

CONCLUSIONS

HVHF decreases vasopressor requirements in human septic shock and affects anaphylatoxin levels differently than standard CVVH.

Continuous veno-venous hemofiltration without anticoagulation in high-risk patients

OBJECTIVE

To study the safety and operative efficacy of continuous veno-venous hemofiltration (CVVH) without anticoagulation in patients at high risk of bleeding.

DESIGN

Prospective cohort study and comparison to control group.

SETTING

Tertiary, multidisciplinary intensive care unit.

PATIENTS

Forty hemofiltration circuits in 12 patients with severe acute renal failure (ARF) deemed at high risk of bleeding. Forty control circuits in 14 patients treated with low-dose pre-filter heparin infusion.

INTERVENTIONS

CVVH at 21/h of pump-controlled ultrafiltration without anticoagulation or saline flush in patients at high risk of bleeding. Collection of data at the bedside.

MEASUREMENTS AND MAIN RESULTS

Mean circuit life was 32 h (95% CI: 20-44.4) in patients receiving CVVH without anticoagulation. Forty-three per cent of filters lasted longer than 30 h. Circuit lifespan did not correlate with international normalized ratio (INR), activated partial thromboplastin time (APTT) or platelet count. There were no bleeding complications and azotemic control was not compromised by lack of circuit anticoagulation with a mean serum urea of 16.0 mmol/l (95% CI: 14.9-18.1) during treatment. A control group of consecutive similarly ill patients not at high risk of bleeding received low-dose pre-filter heparin (mean dose 716 IU; 95% CI: 647-785). Their mean filter life was 19.5 h (95% CI: 14.2-23.8), significantly shorter than in the study patients (p = 0.017).

CONCLUSIONS

Critically ill patients at high risk of bleeding who require continuous renal replacement therapy (CRRT) can be safely managed without circuit anticoagulation. This strategy minimizes bleeding risks and is associated with an acceptable filter life. CRRT without anticoagulation should be strongly considered in high-risk patients.

A prospective study of thromboelastography (TEG) and filter life during continuous veno-venous hemofiltration

Anticoagulants are commonly used to prolong circuit life during continuous hemofiltration. However, a clear correlation between routinely performed blood coagulability tests and circuit life has not been demonstrated. This lack of correlation may derive from the limited ability of such tests to describe the likelihood of in vivo clotting. We hypothesized that thromboelastography (TEG), which derives its variables from a closer reproduction of in vivo coagulation, would significantly correlate with filter life. Accordingly, we conducted a prospective pilot study of the correlation between filter life and TEG-derived variables in 21 hemofilters used in 6 critically ill patients admitted to a tertiary intensive care unit. It involved the performance of TEG during steady state anticoagulation, measurement of circuit life, and of routine coagulation variables. The results showed that the mean circuit life was 20.7+/-4.0 h despite an average aPTT of 67.7+/-12.8 s and a mean heparin dose of 472.5+/-96.2 IU/h. The mean INR was 1.4+/-1 and the mean platelet count was 118+/-16 x 10(3)/mm3. Although several TEG variables correlated with heparin dose (p < 0.03), no correlation was found between any of the routine coagulation variables or any of the TEG variables and circuit life. In conclusion, no significant correlation between TEG derived variables or routinely measured coagulation variables and circuit life could be demonstrated. These findings suggest that such tests are not useful indicators of circuit anticoagulation adequacy and that factors other than blood coagulability may play a role in circuit failure.

Problems associated with nursing staff shortage: an analysis of the first 3600 incident reports submitted to the Australian Incident Monitoring Study (AIMS-ICU)

Although many studies have attempted to define appropriate nursing staff levels, allocation and patient dependency, minimal data is available on the effect of nursing staff shortage (NSS) on quality of care provided in intensive care. This study aimed to identify incidents associated with staff shortage as reported to the Australian Incident Monitoring Study-ICU (AIMS-ICU) project and to assess their estimated effect on patient outcome. A search of narrative keywords and contributing factors identified 89 nursing staff shortage incidents (NSS-INCIDENTS) and 373 incidents involving nursing staff shortage contributing factors (NSS-CF). NSS resulted from inappropriate rostering for current patient load (81%) and inability to respond to increased unit activity (19%). Most frequent associated incidents included problems with: drug administration/documentation (47), patient supervision (20), set-up of ventilators/equipment (16), and accidental extubation (14). Undesirable patient outcomes included: major physiological change (22%), patient/relative dissatisfaction (12%), and physical injury (3%). This study suggests that inadequate staffing results in incidents and compromised patient safety.

Australian Incident Monitoring Study in intensive care: local unit review meetings and report management

The Australian Incident Monitoring Study in the intensive care unit (AIMS-ICU) is a national study established through nursing and medical collaboration to develop, introduce and evaluate an anonymous voluntary incident reporting system. To ensure incident monitoring results in improved patient safety, it is essential that reported incidents are followed up regularly. Local unit review meetings are an effective forum for discussion and review of reports amongst a wide group of practitioners from the intensive care unit (ICU). All staff should be invited to participate in order to suggest preventative strategies, report on incident follow up and explore national study findings. Ongoing momentum of the project is assisted by highlighting its positive contributions to patient care and safety via newsletters, poster displays and targeted correspondence. New staff require orientation to the reporting system and assurance regarding safety of data. The emphasis must focus on the system, not the individual.

The Australian Incident Monitoring Study in Intensive Care: AIMS-ICU. The development and evaluation of an incident reporting system in intensive care

Intensive care units are complex, dynamic patient management environments. Incidents and accidents can be caused by human error, by problems inherent in complex systems, or by a combination of these. Study objectives were to develop and evaluate an incident reporting system. A report form was designed eliciting a description of the incident, contextual information and contributing factors. Staff group sessions using open-ended questions, observations in the workplace and a review of earlier narratives were used to develop the report form. Three intensive care units participated in a two-month evaluation study. Feedback questionnaires were used to assess staff attitudes and understanding, project design and organization. These demonstrated a positive attitude and good understanding by more than 90% participants. Errors in communication, technique, problem recognition and charting were the predisposing factors most commonly chosen in the 128 incidents reported. It was concluded that incident monitoring may be a suitable technique for improving patient safety in intensive care.

The Australian Incident Monitoring Study in Intensive Care: AIMS-ICU. An analysis of the first year of reporting

The AIMS-ICU project is a national study set up to develop, introduce and evaluate an anonymous voluntary incident reporting system for intensive care. ICU staff members reported events which could have reduced, or did reduce, the safety margin for the patient. Seven ICUs contributed 536 reports, which identified 610 incidents involving the airway (20%), procedures (23%), drugs (28%), patient environment (21%), and ICU management (9%). Incidents were detected most frequently by rechecking the patient or the equipment, or by prior experience. No ill effects or only minor ones were experienced by most patients (short-term 76%, long-term 92%) as a result of the incident. Multiple contributing factors were identified, 33% system-based and 66% human factor-based. Incident monitoring promises to be a useful technique for improving patient safety in the ICU, when sufficient data have been collected to allow analysis of sets of incidents in defined "clinical situations".

Adverse incident reporting in intensive care

This prospective, observational, anonymous incident reporting study aimed to identify and correct factors leading to reduced patient safety in intensive care. An incident was any event which caused or had the potential to cause harm to the patient, but included problems in policy or procedure. Reports were discussed at monthly meetings. Of 390 incidents, 106 occasioned "actual" harm and 284 "potential" harm. There was one death, 86 severe complications and 88 complications of minor severity. Most were transient but the effects of 24 lasted up to a week. Most incidents affected cardiovascular and respiratory systems. Incident categories involved drugs, equipment, management or procedures. Incident causes were knowledge-based, rule-based, technical, slip/lapse, no error or unclassifiable. The study has identified some human and equipment performance problems in our intensive care unit. Correction of these should lead to a reduction in the future incidence of those events and hence an increased level of patient safety.