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Prolonged intermittent renal replacement therapy (PIRRT) is a recently defined acute modality for critically ill patients, and in theory combines the superior detoxification and haemodynamic stability of continuous renal replacement therapy (CRRT) with the operational convenience and low cost of intermittent haemodialysis (iHD). We performed a retrospective cohort study for all critically ill adults treated with renal replacement therapy at our centre in Auckland, New Zealand from 1 January 2002 to 31 December 2008. The exposure of interest was modality (PIRRT, CRRT, iHD). Primary and secondary outcomes were patient mortality determined at hospital discharge and 90 days post renal replacement therapy inception, respectively. Co-variates included co-morbidity and baseline illness severity measured by Acute Physiology and Chronic Health Evaluation IV and Sepsis-Related Organ Failure Assessment (SOFA) and time-varying illness severity measured by daily SOFA scores. We used Marginal Structural Modelling to estimate mortality risk adjusting for both time-varying illness severity and modality exposure. A total of 146 patients with 633 treatment-days had sufficient data for modelling. With PIRRT as the reference, the adjusted hazard ratios for patient hospital mortality were 1.31 (0.60 to 2.90) for CRRT and 1.22 (0.21 to 2.29) for iHD. Corresponding estimates for mortality at 90 days were 0.96 (0.39 to 2.36) and 2.22 (0.49 to 10.11), respectively, reflecting the poorer longer-term prognosis of patients still on iHD at hospital discharge with delayed or non-recovery of acute kidney injury. Our study supports the recent increased use of PIRRT, which within limits can be regarded as safe and effective.

Emphysema often affects the lungs in a heterogeneous fashion, and collapse or removal of severely hyperinflated portions of lung can improve overall lung function and symptoms. The role of lung volume reduction (LVR) surgery in selected patients is well established, but that of non-surgical LVR is still being defined. In particular, use of endobronchial LVR is still under development. This case report describes a 48-year-old non-smoker with severe bullous emphysema complicated by acute hypercapnic respiratory failure, who was successfully treated by endobronchial valve placement while intubated in an intensive care unit.

It is unknown whether fluid resuscitation with colloid or crystalloid in patients with severe sepsis or septic shock is associated with an improvement in clinical outcome. This randomized controlled trial determined the feasibility of conducting a large trial testing resuscitation with pentastarch vs normal saline in early septic shock, powered for a difference in mortality.At three Canadian and one New Zealand academic centre, 40 patients with early septic shock defined by at least two systemic inflammatory response syndrome criteria, infectious source, and persistent hypotension afteror= 1 L of crystalloid fluid were recruited. Feasibility measures were patient recruitment, blinding of the study fluids, and acceptability of the goal directed algorithms. Boluses of blinded normal saline or pentastarch (500 mL - maximum 3 L or 28 mL x kg(-1)) were administered within goal directed care for the first 12 hr.Of 161 patients screened, 121 were excluded and 40 patients were enrolled, for a recruitment rate of 0.75 patients/site/month. Only 57% of physicians and 54% of nurses correctly guessed the study fluid (P = 0.46 and P = 0.67, respectively). The goal directed algorithms were acceptable to 97% of physicians.The ability to recruit patients in this pilot randomized controlled trial was below expectations. Blinding of study fluids was adequate, and resuscitation algorithms were acceptable to most physicians. Methods to improve recruitment are required to enhance the feasibility of conducting a multicentre fluid resuscitation trial in early septic shock.

Background Sustained low-efficiency daily dialysis (SLEDD) is an increasingly popular renal replacement therapy for intensive care unit (ICU) patients. SLEDD has been previously reported to provide good solute control and haemodynamic stability. However, continuous renal replacement therapy (CRRT) is considered superior by many ICU practitioners, due first to the large amounts of convective clearance achieved and second to the ability to deliver treatment independently of nephrology services. We report on a program of sustained low-efficiency daily diafiltration (SLEDD-f) delivered autonomously by ICU nursing personnel, and benchmark solute clearance data with recently published reports that have provided dose-outcome relationships for renal replacement therapy in this population. Methods SLEDD-f treatments were delivered using countercurrent dialysate flow at 200 ml/min and on-line haemofiltration at 100 ml/min for 8 h on a daily or at least alternate day basis. All aspects of SLEDD-f were managed by ICU nursing personnel. Clinical parameters, patient outcomes and solute levels were monitored. Kt/V, corrected equivalent renal urea clearance (EKRc) and theoretical Kt/V(B12) were calculated. Results Fifty-six SLEDD-f treatments in 24 critically ill acute renal failure patients were studied. There were no episodes of intradialytic hypotension or other complications. Observed hospital mortality was 46%, not significantly different from the expected mortality as determined from the APACHE II illness severity scoring system. Electrolyte control was excellent. Kt/V per completed treatment was 1.43+/-0.28 (0.96-2.0). Kt/V(B12) per completed treatment was 1.02+/-0.21 (0.6-1.38). EKRc for patients was 35.7+/-6.4 ml/min (25.0-48.2). Conclusion SLEDD-f provides stable renal replacement therapy and good clinical outcomes. Logistic elements of SLEDD-f delivery by ICU nursing personnel are satisfactory. Small solute clearance is adequate by available standards for CRRT and intermittent haemodialysis, and larger solute clearance considerable. SLEDD-f is a viable alternative to CRRT in this setting.

Purpose Randomized, controlled trials of fluid resuscitation in early septic shock face many logistic challenges. We describe the Fluid Resuscitation with 5% albumin versus Normal Saline in Early Septic Shock (PRECISE) pilot trial study design and report feasibility of patient recruitment. Materials and Methods Six Canadian academic centers enrolled adult patients with early suspected septic shock from the emergency department and intensive care unit department. Consent was deferred. Using concealed allocation, participants were randomized to either 5% albumin or 0.9% sodium chloride. Blinded fluid resuscitation started immediately and continued for 7 days in the intensive care unit. Target recruitment was established a priori at 2 patients per site per month. Results Fifty-one patients were enrolled; 50 patients received study fluid. We recruited a median of 2.5 patients (interquartile range [IQR], 1.5-3.0) per site per month into the trial. Median age and Acute Physiology and Chronic Health Evaluation II scores were 64.5 (IQR, 55.0-78.0) and 25.0 (IQR, 20.0-29.0), respectively. Most patients (n = 37 [74.0%]) were enrolled from the emergency department for a median of 1.6 hours (IQR, 0.8-3.5 hours) from their first hypotensive event and received a median of 2.4 L (IQR, 1.5-3.0 L) of resuscitation fluid before inclusion. Consent was deferred for 44 patients (89.8%). Conclusions Patient recruitment into the PRECISE pilot trial met our prespecified feasibility targets, and the PRECISE team is planning the larger trial.

Background Prolonged intermittent renal replacement therapy (PIRRT) is a dialysis modality for critically ill patients that in theory combines the superior detoxification and haemodynamic stability of the continuous renal replacement therapy (CRRT) with the operational convenience, reduced haemorrhagic risk and low cost of conventional intermittent haemodialysis. However, the extent to which PIRRT should replace these other modalities is uncertain because comparative studies of mortality are lacking. We retrospectively examined the mortality data from three general intensive care units (ICUs) in different countries that have switched their predominant therapeutic approach from CRRT to PIRRT. We assessed whether this practice change was associated with a change in mortality rate. Methods Data were analysed from ICUs in New Zealand, Australia and Italy. The study population comprised all patients requiring renal replacement therapy from 1 January 1995 to 31 December 2005 (n = 1347), the period of time spanning the change from CRRT to PIRRT in each unit. Poisson regression models were used to estimate the incident rate ratio (IRR) for death, comparing the periods before and after change to PIRRT in each unit. Estimates were adjusted for patient illness severity (APACHE II score) and for the underlying time trend in mortality rate over time. Results The change from CRRT to PIRRT was not associated with any increase in mortality rate, with an adjusted IRR of 1.02 (0.61-1.71). The IRR was virtually identical in the three ICUs (P-value = 0.63 for the difference in the IRR between ICUs). Conclusions Switching from CRRT to PIRRT was not associated with a change in mortality rate. Pending the results of a randomized trial, our study provides evidence that PIRRT might be equivalent to CRRT in the general ICU patient.

Emphysema often affects the lungs in a heterogeneous fashion, and collapse or removal of severely hyperinflated portions of lung can improve overall lung function and symptoms. The role of lung volume reduction (LVR) surgery in selected patients is well established, but that of non-surgical LVR is still being defined. In particular, use of endobronchial LVR is still under development. This case report describes a 48-year-old non-smoker with severe bullous emphysema complicated by acute hypercapnic respiratory failure, who was successfully treated by endobronchial valve placement while intubated in an intensive care unit.

To test whether a reduction in air temperature within the clinical range [37 degrees C to 30, 100% relative humidity (RH)] altered mucus transport velocity (MTV) and ciliary beat frequency (CBF) in an in vitro ovine tracheal model.Controlled laboratory study.University research laboratory.Farm-reared sheep.Tracheae were mounted flat in an organ bath. Krebs Henseleit bathed the serosal surface and air at 100% (RH) was passed over the mucosal surface at 4 l/min. Cilial beat frequency (CBF) was measured photo-electrically and mucus transport velocity (MTV) by timing movement. After 2 h at 37 degrees C (100% RH) the tissue was either maintained with those settings (controls), or the air temperature reduced to 34 degrees C or 30 degrees C. Tissue was taken for histology before and after each experiment.CBF was 19.8+/-2.7 beats/s and MTV 5.7+/-2.6 mm/min in tissue exposed to air at 37 degrees C. Cilial activity continued for up to 6 h in the controls but mucus transport was more fragile. Reduction of the air temperature to either 34 degrees C or 30 degrees C led to a decrease in both CBF and MTV and, frequently, total mucociliary failure. There was a reduction in epithelial mucous cell numbers in all preparations. Tissues exposed to low temperature had additional abnormal histology.Delivery of inspired gas at 30 degrees C, or even 34 degrees C, with 100% RH may not be sufficient to prevent epithelial damage occurring during 6 h exposure.

The optimal level of inspired heat and humidity for patients receiving long-term mechanical ventilation is still the subject of debate. Many laboratory studies examining surrogate markers for optimal humidity suggest that inspired gas should be at body temperature and fully saturated. The aim of this study was to determine the inspired gas condition that was thermodynamically neutral to the airway of intubated patients, and also examine the contribution of the endotracheal tube to airway heat and water balance.Prospective, block-randomized, observational study.General adult intensive care unit of a metropolitan teaching hospital.Ten adult patients requiring intermittent positive pressure ventilation for nonpulmonary reasons.Each patient was given four different gas conditions--30 degrees C, 30 mg/L; 34 degrees C, 38 mg/L; 37 degrees C, 44 mg/L; and 40 degrees C, 50 mg/L--to breathe in random order.Inspired and expired gas temperature and humidity, and the temperature gradient down the endotracheal tube, were measured and the inspired gas condition that gave thermodynamic neutrality was determined. This was found to be gas at body temperature, saturated. Airway workload and airway water loss increased linearly as the inspired gas departed from this condition, at approximately 1.4 kJ/hr/ degrees C and 0.5 mL/hr/ degrees C, respectively. The endotracheal tube contributed very little to heat and water exchange.Inspired gas at body temperature and saturated is thermodynamically neutral to the intubated airway, and thus may be considered the optimal condition for ventilation lasting more than a few hours.

To review the available literature on the relationship between the humidity and temperature of inspired gas and airway mucosal function.International computerized databases and published indices, experts in the field, conference proceedings, bibliographies.Two hundred articles/texts on respiratory tract physiology and humidification were reviewed. Seventeen articles were selected from 40 articles for inclusion in the published data verification of the model. Selection was by independent reviewers. Extraction was by consensus, and was based on finding sufficient data.A relationship exists between inspired gas humidity and temperature, exposure time to a given humidity level, and mucosal function. This relationship can be modeled and represented as an inspired humidity magnitude vs. exposure time map. The model is predictive of mucosal function and can be partially verified by the available literature. It predicts that if inspired humidity deviates from an optimal level, a progressive mucosal dysfunction begins. The greater the humidity deviation, the faster the mucosal dysfunction progresses.A model for the relationship between airway mucosal dysfunction and the combination of the humidity of inspired gas and the duration over which the airway mucosa is exposed to that humidity is proposed. This model suggests that there is an optimal temperature and humidity above which, and below which, there is impaired mucosal function. This optimal level of temperature and humidity is core temperature and 100% relative humidity. However, existing data are only sufficient to test this model for gas conditions below core temperature and 100% relative humidity. These data concur with the model in that region. No studies have yet looked at this relationship beyond 24 hrs. Longer exposure times to any given level of inspired humidity and inspired gas temperatures and humidities above core temperature and 100% relative humidity need to be studied to fully verify the proposed model.