Critical Care - Most accessed articles

Clinical review: Acid-base abnormalities in the intensive care unit - part II

2004-10-20T00:00:00Z

Acid–base abnormalities are common in the critically ill. The traditional classification of acid–base abnormalities and a modern physico-chemical method of categorizing them will be explored. Specific disorders relating to mortality prediction in the intensive care unit are examined in detail. Lactic acidosis, base excess, and a strong ion gap are highlighted as markers for increased risk of death.

A critique of fluid bolus resuscitation in severe sepsis

Andrew Hilton — 2012-01-25T00:00:00Z

Resuscitation of septic patients by means of one or more fluid boluses is recommended by guidelines from multiple relevant organizations and as a component of surviving sepsis campaigns. The technique is considered a key and life-saving intervention during the initial treatment of severe sepsis in children and adults. Such recommendations, however, are only based on expert opinion and lack adequate experimental or controlled human evidence. Despite these limitations, fluid bolus therapy (20 to 40 ml/kg) is widely practiced and is currently considered a cornerstone of the management of sepsis. In this pointof-view critique, we will argue that such therapy has weak physiological support, has limited experimental support, and is at odds with emerging observational data in several subgroups of critically ill patients or those having major abdominal surgery. Finally, we will argue that this paradigm is now challenged by the findings of a large randomized controlled trial in septic children. In the present article, we contend that the concept of large fluid bolus resuscitation in sepsis needs to be investigated further.

Clinical experience with power injectable peripherally inserted central catheters in intensive care patients

Mauro Pittiruti — 2012-02-04T00:00:00Z

IntroductionIn intensive care units (ICU), peripherally inserted central catheters (PICC) may be an alternative option to standard central venous catheters, particularly in patients with coagulation disorders or at high risk for infection. Some limits of PICCs (such as low flow rates) may be overcome by the use of power-injectable catheters.MethodWe have retrospectively reviewed all the power injectable PICCs inserted in adult and pediatric patients in the ICU during a 12-month period, focusing on the rate of complications at insertion and during maintenance. Results: We have collected 89 power injectable PICCs (in adults and in children), both multiple and single lumen. All insertions were successful. There were no major complications at insertion and no episodes of catheter-related blood stream infection. Non-infective complications during management were not clinically significant. There was one episode of symptomatic thrombosis during the stay in ICU and one episode after transfer of the patient in a non-intensive ward. Conclusions: Power injectable PICCs have many advantages in the ICU: they can be used as multi-purpose central lines for any type of infusion including high flow infusion, for hemodynamic monitoring, and for high-pressure injection of contrast media during radiological procedures. Their insertion is successful in 100% of cases and is not associated with significant risks, even in patients with coagulation disorders. Their maintenance is associated with an extremely low rate of infective and non-infective complications.

Use of renal replacement therapies in special groups of ICU patients

Eric Hoste — 2012-01-19T00:00:00Z

Acute kidney injury (AKI) in ICU patients is typically associated with other severe conditions that require special attention when renal replacement therapy (RRT) is performed. RRT includes a wide range of techniques, each with specific characteristics and implications for use in ICU patients. In the present review we discuss a wide range of conditions that can occur in ICU patients who have AKI, and the implications this has for RRT. Patients at increased risk for bleeding should be treated without anticoagulation or with regional citrate anticoagulation. In patients who are haemodynamically unstable, continuous therapies are most often employed. These therapies allow slow removal of volume and guarantee a stable blood pH. In patients with cerebral oedema, continuous therapy is recommended in order to prevent decreased cerebral blood flow, which will lead to cerebral ischemia. Continuous therapy will also prevent sudden change in serum osmolality with aggravation of cerebral oedema. Patients with hyponatraemia, as in liver failure or decompensated heart failure, require extra attention because a rapid increase of serum sodium concentration can lead to irreversible brain damage through osmotic myelinolysis. Finally, in patients with severe lactic acidosis, RRT can be used as a bridging therapy, awaiting correction of the underlying cause. Especially in ICU patients who have severe AKI, treatment with RRT requires balancing the pros and cons of different options and modalities. Exact and specific guidelines for RRT in these patients are not available for most clinical situations. In the present article we provide an update on the existing evidence.

Weaning from mechanical ventilation

Inmaculada Alía — 2000-02-18T00:00:00Z

Practice guidelines on weaning should be based on the results of several well-designed randomized studies performed over the last decade. One of those studies demonstrated that immediate extubation after successful trials of spontaneous breathing expedites weaning and reduces the duration of mechanical ventilation as compared with a more gradual discontinuation of ventilatory support. Two other studies showed that the ability to breathe spontaneously can be adequately tested by performing a trial with either T-tube or pressure support of 7 cmH2O lasting either 30 or 120 min. In patients with unsuccessful weaning trials, a gradual withdrawal for mechanical ventilation can be attempted while factors responsible for the ventilatory dependence are corrected. Two randomized studies found that, in difficult-to-wean patients, synchronized intermittent mandatory ventilation (SIMV) is the most effective method of weaning.

Clinical utility of biomarkers of endothelial activation in sepsis - a systematic review

Katharine Xing — 2012-01-16T00:00:00Z

IntroductionA strong biologic rationale exists for targeting markers of endothelial cell (EC) activation as clinically informative biomarkers to improve diagnosis, prognostic evaluation or risk-stratification of patients with sepsis. Methods: The objective was to review the literature on the use of markers of EC activation as prognostic biomarkers in sepsis. MEDLINE was searched for publications using the keyword 'sepsis' and any of the identified endothelial-derived biomarkers in any searchable field. All clinical studies evaluating markers reflecting activation of ECs were included. Studies evaluating other exogenous mediators of EC dysfunction and studies of patients with malaria and febrile neutropenia were excluded. Results: Sixty-one studies were identified that fulfilled the inclusion criteria. Overall, published studies report positive correlations between multiple EC-derived molecules and the diagnosis of sepsis, supporting the critical role of EC activation in sepsis. Multiple studies also reported positive associations for mortality and severity of illness, although these results were less consistent than for the presence of sepsis. Very few studies, however, reported thresholds or receiver operating characteristics that would establish these molecules as clinically-relevant biomarkers in sepsis. Conclusions: Multiple endothelial-derived molecules are positively correlated with the presence of sepsis in humans, and variably correlated to other clinically-important outcomes. The clinical utility of these biomarkers is limited by a lack of assay standardization, unknown receiver operating characteristics and lack of validation. Additional large-scale prospective clinical trials will be required to determine the clinical utility of biomarkers of endothelial activation in the management of patients with sepsis.

Acute renal failure - definition, outcome measures, animal models, fluid therapy and information technology needs: the Second International Consensus Conference of the Acute Dialysis Quality Initiative (ADQI) Group

Rinaldo Bellomo — 2004-05-24T00:00:00Z

IntroductionThere is no consensus definition of acute renal failure (ARF) in critically ill patients. More than 30 different definitions have been used in the literature, creating much confusion and making comparisons difficult. Similarly, strong debate exists on the validity and clinical relevance of animal models of ARF; on choices of fluid management and of end-points for trials of new interventions in this field; and on how information technology can be used to assist this process. Accordingly, we sought to review the available evidence, make recommendations and delineate key questions for future studies. Methods: We undertook a systematic review of the literature using Medline and PubMed searches. We determined a list of key questions and convened a 2-day consensus conference to develop summary statements via a series of alternating breakout and plenary sessions. In these sessions, we identified supporting evidence and generated recommendations and/or directions for future research. Results: We found sufficient consensus on 47 questions to allow the development of recommendations. Importantly, we were able to develop a consensus definition for ARF. In some cases it was also possible to issue useful consensus recommendations for future investigations. We present a summary of the findings. (Full versions of the six workgroups' findings are available on the internet at http://www.ADQI.net) Conclusion: Despite limited data, broad areas of consensus exist for the physiological and clinical principles needed to guide the development of consensus recommendations for defining ARF, selection of animal models, methods of monitoring fluid therapy, choice of physiological and clinical end-points for trials, and the possible role of information technology.

Glucocorticoid therapy for trauma - ready for prime time?

Sachin Yende — 2012-01-20T00:00:00Z

Background: The role of stress-dose hydrocortisone in the management of trauma patients is currently unknown.ObjectiveTo test the efficacy of hydrocortisone therapy in trauma patients.DesignMulticenter randomized, double blind, placebo-controlled study.Setting: Seven ICU's in France during November 2006 to August 2009.Subjects: 150 patients with severe trauma who required ICU stay for at least 48 hours were included in the study.Intervention: Patients were randomly assigned to a continuous intravenous infusion of either hydrocortisone (200 mg/d for 5 days, followed by 100 mg on day 6 and 50 mg on day 7) or placebo. The treatment was stopped if patients had an appropriate adrenal response.Outcomes: Hospital-acquired pneumonia within 28 days. Secondary outcomes included the duration of mechanical ventilation, ICU length of stay, hyponatremia, and death. Results: An intention-to-treat (ITT) analysis included 149 patients and the modified ITT analysis included 113 patients with corticosteroid insufficiency. In the ITT analysis, 26 of 73 patients (35.6%) treated with hydrocortisone and 39 of 76 patients (51.3%) receiving placebo developed hospital-acquired pneumonia by day 28 (hazard ratio [HR], 0.51; 95% confidence interval [CI], 0.30-0.83; P = .007). In the modified ITT analysis, 20 of 56 patients (35.7%) in the hydrocortisone group and 31 of 57 patients (54.4%) in the placebo group developed hospital-acquired pneumonia by day 28 (HR, 0.47; 95% CI, 0.25-0.86; P = .01). Mechanical ventilation-free days increased with hydrocortisone use by 4 days (95% CI, 2-7; P = .001) in the ITT analysis and 6 days (95% CI, 2-11; P < .001) in the modified ITT analysis. Hyponatremia was observed in 7 of 76 (9.2%) in the placebo group vs. none in the hydrocortisone group (absolute difference, 9%; 95% CI, 16% to 3%; P = .01). Four of 76 patients (5.3%) in the placebo group and 6 of 73 (8.2%) in the hydrocortisone group died (absolute difference, 3%; 95% CI, 5% to 11%; P = .44). Conclusions: In intubated trauma patients, the use of an intravenous stress-dose of hydrocortisone, compared with placebo, resulted in a decreased risk of hospital-acquired pneumonia.

Early initiation of low-dose corticosteroid therapy in the management of septic shock: a retrospective observational study

Hey Yun Park — 2012-01-07T00:00:00Z

IntroductionThe use of low-dose steroid therapy in the management of septic shock has been extensively studied. However, the association between the timing of low-dose steroid therapy and the outcome has not been evaluated. Therefore, we evaluated whether early initiation of low-dose steroid therapy is associated with mortality in patients with septic shock. Methods: We retrospectively analyzed the clinical data of 178 patients who received low-dose corticosteroid therapy for septic shock between January 2008 and December 2009. Time-dependent Cox regression models were used to adjust for potential confounding factors in the association between the time to initiation of low-dose corticosteroid therapy and in-hospital mortality. Results: The study population consisted of 107 men and 71 women with a median age of 66 (interquartile range, 54-71) years. The 28-day mortality was 44% and low-dose corticosteroid therapy was initiated within a median of 8.5 (3.8-19.1) hours after onset of septic shock-related hypotension. Median time to initiation of low-dose corticosteroid therapy was significantly shorter in survivors than in non-survivors (6.5 hours vs. 10.4 hours; P = 0.0135). The mortality rates increased significantly with increasing quintiles of time to initiation of low-dose corticosteroid therapy (P = 0.0107 for trend). Other factors associated with 28-day mortality were higher Simplified Acute Physiology Score (SAPS) 3 (P < 0.0001) and Sequential Organ Failure Assessment (SOFA) scores (P = 0.0007), dose of vasopressor at the time of initiation of low-dose corticosteroid therapy (P < 0.0001), need for mechanical ventilation (P = 0.0001) and renal replacement therapy (P < 0.0001), while the impaired adrenal reserve did not affect 28-day mortality (81% vs. 82%; P = 0.8679). After adjusting for potential confounding factors, the time to initiation of low-dose corticosteroid therapy was still significantly associated with in-hospital mortality (adjusted OR 1.025, 95% CI 1.007-1.044, P = 0.0075). The early therapy group (administered within 6 hours after the onset of septic shock, n = 66) had a 37% lower mortality rate than the late therapy group (administered after 6 hours after the onset of septic shock, n = 112) (32% vs. 51%, P = 0.0132). Conclusions: Early initiation of low-dose corticosteroid therapy was significantly associated with decreased mortality.

Alkaline phosphatase for treatment of sepsis-induced acute kidney injury: a prospective randomized double-blind placebo-controlled trial

Peter Pickkers — 2012-01-23T00:00:00Z

IntroductionTo evaluate whether AP treatment improves renal function in sepsis-induced acute kidney injury (AKI) a prospective, double-blind, randomized, placebo-controlled study in critically ill patients with severe sepsis or septic shock with evidence of AKI was performed. Methods: Thirty-six adult patients with severe sepsis or septic shock according to Systemic Inflammatory Response Syndrome criteria and renal injury defined according to the AKI Network criteria were included. Dialysis intervention was standardized according to Acute Dialysis Quality Initiative consensus. Intravenous infusion of alkaline phosphatase (bolus injection of 67.5U/kg body weight followed by continuous infusion of 132.5U/kg/24h for 48 hours, or placebo) starting within 48 hours of AKI onset and followed up to 28 days post-treatment. The primary outcome variable was progress in renal function variables (endogenous creatinine clearance, requirement and duration of renal replacement therapy, RRT) after 28 days. The secondary outcome variables included changes in circulating inflammatory mediators, urinary excretion of biomarkers of tubular injury, and safety. Results: There was a significant (p=0.02) difference in favor of AP treatment relative to controls for the primary outcome variable. Individual renal parameters showed that endogenous creatinine clearance (baseline to day 28) was significantly higher in the treated group relative to placebo (from 50+/-27 to 108+/-73mL/min (mean+/-SEM) for the AP group; and from 40+/-37 to 65+/-30mL/min for placebo; p=0.01). Reductions in RRT requirement and duration did not reach significance. The results in renal parameters were supported by significantly more pronounced reductions in the systemic markers C-reactive protein, Interleukin 6, LPS-binding protein, and in the urinary excretion of Kidney Injury Molecule-1 and Interleukin-18 in AP-treated patients relative to placebo. The Drug Safety Monitoring Board did not raise any issues throughout the trial. Conclusions: The improvements in renal function suggest alkaline phosphatase is a promising new treatment for patients with severe sepsis or septic shock with AKI.