Nicholas Barrett

Renal replacement therapy in critically ill patients with acute kidney injury--when to start.

BACKGROUND Despite the frequent use of renal replacement therapy (RRT) for patients with acute kidney injury (AKI) in the intensive care unit (ICU), there is no accepted consensus on the optimal indications and timing. METHODS The aim of this paper is to identify optimal triggers for RRT in critically ill patients with AKI. RESULTS We examined data from 2 randomized controlled trials, 2 prospective studies and 13 retrospective trials and found large variation in the different parameters and cut-offs for initiation of RRT. No single biochemical parameter was adequate to define the optimal indication and time to commence RRT. Degree of fluid overload, oliguria and associated non-renal organ failure appeared to be more appropriate parameters for initiation of RRT. We propose a clinical algorithm based on regular assessment of the patients condition and trends in these parameters. It is intended to aid the process of deciding when to start RRT in critically ill adult patients with AKI. CONCLUSION Available evidence suggests that the decision when to start RRT in critically ill patients with AKI should be based on trends in the patients severity of illness, presence of oliguria and fluid overload and associated non-renal organ failure rather than specific serum creatinine or urea values.

An international survey

BACKGROUND The last decade has seen an increase in the number of centres able to provide venovenous extracorporeal membrane oxygenation (VV-ECMO) internationally across different health care systems. To support this growth, a variety of staffing arrangements have been adopted depending on local need and availability of resources, both in terms of manpower and finances to safely meet the complex needs of the patient and circuit management. AIM The aim of the survey was to describe current staffing arrangements of care provision for adult patients on VV-ECMO, with a focus on understanding the professional roles and responsibilities of staff managing the circuit in order to inform further discussion around different approaches to staffing. METHODS We conducted a cross-sectional international survey using an electronic questionnaire emailed to 177 worldwide ECMO centres treating adult patients with acute respiratory failure. The survey questions were generated through an internal and external iterative process and assessed for clarity, content and face validity. RESULTS The response rate was 82%. Respondents managed extracorporeal oxygenation for adult respiratory alone (75%) or in combination with adult cardiac (67%), paediatric respiratory (62%) and paediatric cardiac (58%). The specialist nurse to patient ratio was 1:1 in 59% of centres, with 24-h/day presence in 74%. Overall, the specialist nurse provided the 24-h/day management of the circuit, including interventions. Perfusionists were responsible for the technical aspects of circuit management. CONCLUSIONS A specialist nurse with perfusion backup is the staffing arrangement implemented by most centres and likely reflects the most efficient use of the professional competences available. RELEVANCE TO CLINICAL PRACTICE Staffing for adult respiratory extracorporeal support has important implications for the planning of workforce, training and education, quality of service and the number of ECMO beds available.

Prevalence of Venous Thrombosis Following Venovenous Extracorporeal Membrane Oxygenation in Patients With Severe Respiratory Failure.

Objectives:Venovenous extracorporeal membrane oxygenation for patients with severe respiratory failure is increasingly common. There has been a significant change in the population, technology, and approach used for venovenous extracorporeal membrane oxygenation over the last 10 years. The objective of this study is to describe the prevalence of postdecannulation deep vein thrombosis in the cannulated vessel in adults who have received venovenous extracorporeal membrane oxygenation for severe respiratory failure. Design:A single-center, retrospective, observational cohort, electronic note review study. Setting:Tertiary referral university teaching hospital. Patients:Patients commenced on venovenous extracorporeal membrane oxygenation for severe respiratory failure. Interventions:None. Measurements and Main Results:We identified 103 patients commenced on extracorporeal membrane oxygenation with 81 survivors from December 2011 to February 2014. We performed postdecannulation venous Doppler ultrasound in 88.9% of extracorporeal membrane oxygenation survivors. The prevalence of deep vein thrombosis in the cannulated vessel following extracorporeal membrane oxygenation is 8.1/1,000 cannula days in patients who were screened. Conclusions:The prevalence of deep vein thrombosis following decannulation from extracorporeal membrane oxygenation for severe respiratory failure is clinically significant, and routine venous Doppler ultrasound following decannulation is warranted in this population.

Use of an Electromagnetic Device Compared With Chest X-ray to Confirm Nasogastric Feeding Tube Position in Critical Care.

BACKGROUND Insertion of nasogastric feeding tubes (NGTs) is common in critical care. However, misplacement is frequent and can carry a significant morbidity. Current methods to confirm position of NGTs are not reliable in this setting. We retrospectively compared the position of NGTs using an electromagnetically guided nasogastric tube (e-NGT) with that demonstrated by chest x-ray (CXR), the proportion of lung placements avoided, and the time taken to establish enteral feeding. METHODS This was a retrospective, observational study undertaken in a tertiary referral, adult intensive care unit between February 2006 and November 2013. Patients were included if they had a radiologically confirmed NGT. All CXRs were independently reviewed by an intensivist to determine position, and a subset of patients had their e-NGT image independently reviewed for quality control. Statistical analysis was in the form of sensitivity and specificity and descriptive where indicated. RESULTS In total, 121 NGT placements in 113 patients were analyzed. We found a sensitivity of 98% (95% confidence interval [CI], 93.9%-99.7%) and a specificity of 100% (95% CI, 48.0%-100.0%) when using the e-NGT compared with CXR. In the subset of 51 independently reviewed e-NGT images, 9 lung placements were avoided. The mean (SD) time from e-NGT placement to CXR was 185 (264.4) minutes and to feeding was 404 (77.8) minutes. CONCLUSION When placed by a dedicated team, e-NGT allowed immediate detection of tube misplacement. As such, if used as the sole method for determining NGT position, e-NGTs minimize feeding delay and the need for multiple CXRs with subsequent cost savings.

Electromagnetic Sensor-Guided Enteral Access Systems: A Literature Review.

Enteral feeding is the nutritional support of choice for acutely ill patients with functional gastrointestinal tracts who are unable to swallow. Several benefits including reduced mortality and length of hospital stay have been associated with early initiation of enteral feeding. However, misplacement of conventional nasoenteric tubes is relatively common and can result in complications including pneumothorax. In addition, the need to confirm the position by X-ray can delay the start of using the tube. Eliminating these delays can help patients start feeding, and minimise the adverse impact on initiating hydration and medication. The purpose of this review was to critically examine whether electromagnetic sensor-guided enteral access systems (EMS-EAS) can help overcome the challenges of conventional nasoenteric feeding tube placement and confirmation. The Royal Society of Medicine’s library performed two searches on Medline (1946–March 2014) and Embase (1947–March 2014) covering all papers on Cortrak or electromagnetic or magnetic guidance systems for feeding tubes in adults. Results from the literature search found an agreement between the radiographic and EMS-EAS confirmation of placement. EMS-EAS virtually eliminated the risk of misplacement and pneumothorax was not reported. In addition, studies showed a small decrease in the number of X-rays with EMS-EAS and a reduced average time to start feeding compared with blind placement. This review suggests that EMS-EAS reduces several complications associated with the misplacement of nasoenteric feeding tubes, and that there could be considerable improvements in mortality, morbidity, patient experience and cost if EMS-EAS is used instead of conventional methods.

Quetiapine in refractory hyperactive and mixed intensive care delirium: a case series

IntroductionDelirium affects up to 80% of patients admitted to intensive care units (ICUs) and contributes to increased morbidity and mortality. Haloperidol is the gold standard for treatment, although quetiapine has been successfully used in the management of delirium.MethodsWe conducted a retrospective study of patients admitted to the ICU between February 2008 and May 2010 who were prescribed quetiapine by the attending clinician. Data collected included demographics, history of drug and/or alcohol dependence, ICU and hospital length of stay, length of mechanical ventilation and the duration of treatment with sedatives and medications for delirium. The daily dose of quetiapine was recorded. Hyperactive or mixed delirium was identified by a validated chart review and a Richmond Agitation Sedation Scale (RASS) score persistently greater than 1 for 48 hours despite therapy.ResultsSeventeen patients were included. Delirium onset occurred after a median of five days. Patients were being given at least four agents for delirium prior to the introduction of quetiapine, and they had a median RASS score of 3. Quetiapine was initiated at a 25 mg daily dose and titrated to a median daily dose of 50 mg. The median duration of delirium prior to quetiapine therapy was 15 days. Quetiapine commencement was associated with a reduction in the need for other medications (within 0 to 6 days) and resolution of delirium within a median of four days. Adverse events included somnolence and transient hypotension.ConclusionsThis case series provides an initial effort to explore a possible role for quetiapine in the management of refractory hyperactive and mixed ICU delirium.

Assessment of regional lung mechanics with electrical impedance tomography can determine the requirement for ECMO in patients with severe ARDS

Dear Editor, Patients with severe acute respiratory distress syndrome (ARDS) may require extracorporeal oxygenation (ECMO) as a rescue treatment of refractory hypoxaemia. However, it remains unclear how mechanical ventilation can be optimised to reverse hypoxaemia and maximise lung protection in patients considered for or receiving ECMO [1]. In particular, mechanical ventilation during ECMO [2] may lead to over-distension and under-recruitment, depending on the degree of heterogeneity of regional compliances [3–5]. We wish to describe—using two illustrative cases of patients with severe ARDS with a similar Lung Injury Score, referred to our institution for ECMO—how assessment of regional changes in compliance using electrical impedance tomography (EIT) may assist in the ventilatory strategy prior to or during ECMO. Both patients underwent a recruitment manoeuvre (RM) using a stepwise incremental and decremental positive end-expiratory pressure (PEEP) trial. At each step of PEEP we performed an inspiratory and expiratory occlusion manoeuvre to calculate static respiratory system compliance (Crs) and the global and regional (dorsal and ventral) compliance using EIT (CEIT). CEIT was calculated as the change in impedance (DZ) between the inspiratory and expiratory occlusion manoeuvres of the global or regional signal divided by the static driving airway pressure [(DZi-DZe)/Pplat-PEEP] [6] and normalised for baseline compliance. Regional recruitability was defined as an increase in CEIT and end-expiratory lung volume (EELV) after PEEP trial. Following a RM we identified one patient with potentially recruitable lungs [R] and one with no lung recruitability [NR]. [R] (versus [NR]) had a pre-ECMO PaO2/FiO2 of 66.8 mmHg (versus 68 mmHg), Crs of 14.7 mL/cmH2O (versus 5 mL/cmH2O) and PaCO2 of 79.3 mmHg (versus 68.1 mmHg). Both patients received ECMO with pump flow of 4.7 L/min (versus 5 L/ min) and sweep gas flow of 6 L/min (versus 8 L/min). Crs increased from 14.7 to 25.0 mL/cmH2O (versus 5.0–5.5 mL/ cmH2O); PaO2 and PaCO2 changed post-RM by 19.7 % (versus -5.0 %) and 6.4 % (versus -8.3 %), respectively. The ‘best PEEP’ corresponding to the highest global CEIT was 10 cmH2O (versus 2 cmH2O). At a regional level, however, for [R], the best regional CEIT was at PEEP of 8 cmH2O for the ventral regions (V) and 22 cmH2O for the dorsal regions (D) (versus

A Retrospective Observational Case Series of Low-Flow Venovenous Extracorporeal Carbon Dioxide Removal Use in Patients with Respiratory Failure.

We aimed to describe the use of venovenous extracorporeal carbon dioxide removal (ECCO2R) in patients with hypercapnic respiratory failure. We performed a retrospective case note review of patients admitted to our tertiary regional intensive care unit and commenced on ECCO2R from August 2013 to February 2015. Fourteen patients received ECCO2R. Demographic data, physiologic data (including pH and partial pressure of carbon dioxide in arterial blood [PaCO2]) when starting ECCO2R (t = 0), at 4 hourly intervals for the first 24 hours, then at 24 hour intervals until cessation of ECCO2R, and overall outcome were recorded. Patients are reported separately depending on whether the indication for ECCO2R was an exacerbation of chronic obstructive pulmonary disease (COPD; n = 5), or acute respiratory distress syndrome (ARDS) and persisting hypercapnoea (n = 9). Patients were managed with ECCO2R (Hemolung, ALung Inc, Pittsburgh, PA). Median duration of ECCO2R was 5 days. Four complications related to ECCO2R were reported, none resulting in serious adverse outcomes. Ten patients were discharged from intensive care unit (ICU) alive. A statistically significant improvement in pH (p = 0.012) was demonstrated. Our observational series of ECCO2R shows that this technique can be safely used to achieve therapeutic goals in patients requiring lung protection, and in COPD, in line with current publications in this area.

Justification for Chest Physiotherapy during Ultra‐Protective Lung Ventilation and Extra‐Corporeal Membrane Oxygenation: A Case Study

BACKGROUND AND PURPOSE This case report describes the chest physiotherapy (CPT) intervention provided to a 32-year old man with severe respiratory failure undergoing extra-corporeal membrane oxygenation (ECMO) support and ultra-protective ventilatory strategy. Low tidal volume ventilation when used in patients with extremely low dynamic respiratory compliance may predispose the patient to secretion retention, and the role of CPT in this setting is unclear. METHOD The method used is a single subject case report. Written consent obtained from patients representative. SUMMARY Secretion clearance in this patient was initially limited to suctioning; however, after developing major airway occlusion secondary to impacted secretions, he received intensive CPT consisting of positioning, ventilator hyperinflation, expiratory chest wall shaking and suctioning. After 13 days of two to three times daily CPT, the patient weaned from ECMO support. DISCUSSION Regular CPT may have facilitated secretion clearance and lung recovery in this patient. Future research should investigate the optimal CPT techniques for patients with sub-dead space tidal ventilation and extremely low dynamic respiratory compliance during ECMO with ultra-protective ventilatory strategy (UPVS).

Levosimendan: A retrospective single-center case series

PURPOSE The purpose of this study is to describe the effect of levosimendan (without loading dose) on hemodynamics, inotropes/vasopressors, and mortality in acute heart failure (AHF). MATERIALS AND METHODS Patients who received levosimendan for AHF were analyzed. Levosimendan dose, hemodynamic data, inotrope/vasopressor requirements, and fluid balance before commencement, at conclusion of, and 24 hours after levosimendan were collected. Mortality is also reported. RESULTS Eighty-seven patients were analyzed. The mean levosimendan dose (without loading) was 0.096 μg/kg per minute (±0.014), and mean duration, 26 (±7.2) hours. There was no change in heart rate (start, post, and 24 hours post) (92 [±19], 92 [±26], and 92 [±15]) or mean arterial pressure (69 [±10], 72 [±8], and 72 [±10] mm Hg, respectively). There was a significant reduction in median dobutamine from 7.27 to 0 μg/kg per minute and noradrenaline from 0.20 to 0.1 μg/kg per minute before and 24 hours after. There was a significant increase in both mean cardiac index from 2.38 ± 0.0.72 to 2.98 ± 0.0.77 L/min per square meter and in markers of perfusion: base excess from -2.77 to 0.39 mmol/L, and lactate from 2.1 to 1.4 mmol/L before and 24 hours after infusion. Survival was 53%. CONCLUSIONS Levosimendan, without a loading dose, improved cardiac index and perfusion while allowing a reduction in inotropic/vasopressor requirements in patients with AHF.