Alexandre Boyer

Initiation Strategies for Renal-Replacement Therapy in the Intensive Care Unit

BACKGROUND The timing of renal-replacement therapy in critically ill patients who have acute kidney injury but no potentially life-threatening complication directly related to renal failure is a subject of debate. METHODS In this multicenter randomized trial, we assigned patients with severe acute kidney injury (Kidney Disease: Improving Global Outcomes [KDIGO] classification, stage 3 [stages range from 1 to 3, with higher stages indicating more severe kidney injury]) who required mechanical ventilation, catecholamine infusion, or both and did not have a potentially life-threatening complication directly related to renal failure to either an early or a delayed strategy of renal-replacement therapy. With the early strategy, renal-replacement therapy was started immediately after randomization. With the delayed strategy, renal-replacement therapy was initiated if at least one of the following criteria was met: severe hyperkalemia, metabolic acidosis, pulmonary edema, blood urea nitrogen level higher than 112 mg per deciliter, or oliguria for more than 72 hours after randomization. The primary outcome was overall survival at day 60. RESULTS A total of 620 patients underwent randomization. The Kaplan-Meier estimates of mortality at day 60 did not differ significantly between the early and delayed strategies; 150 deaths occurred among 311 patients in the early-strategy group (48.5%; 95% confidence interval [CI], 42.6 to 53.8), and 153 deaths occurred among 308 patients in the delayed-strategy group (49.7%, 95% CI, 43.8 to 55.0; P=0.79). A total of 151 patients (49%) in the delayed-strategy group did not receive renal-replacement therapy. The rate of catheter-related bloodstream infections was higher in the early-strategy group than in the delayed-strategy group (10% vs. 5%, P=0.03). Diuresis, a marker of improved kidney function, occurred earlier in the delayed-strategy group (P<0.001). CONCLUSIONS In a trial involving critically ill patients with severe acute kidney injury, we found no significant difference with regard to mortality between an early and a delayed strategy for the initiation of renal-replacement therapy. A delayed strategy averted the need for renal-replacement therapy in an appreciable number of patients. (Funded by the French Ministry of Health; ClinicalTrials.gov number, NCT01932190.).

Intrapulmonary percussive ventilation in acute exacerbations of COPD patients with mild respiratory acidosis: a randomized controlled trial [ISRCTN17802078]

IntroductionWe hypothesized that the use of intrapulmonary percussive ventilation (IPV), a technique designed to improve mucus clearance, could prove effective in avoiding further deterioration in patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) with mild respiratory acidosis.MethodsThe study was performed in a medical intensive care unit of a university hospital. Thirty-three patients with exacerbations of COPD with a respiratory frequency ≥ 25/min, a PaCO2 > 45 Torr and 7.35 ≤ pH ≤ 7.38 were included in the study. Patients were randomly assigned to receive either standard treatment (control group) or standard treatment plus IPV (IPV group). The IPV group underwent two daily sessions of 30 minutes performed by a chest physiotherapist through a full face mask. The therapy was considered successful when both worsening of the exacerbation and a decrease in pH to under 7.35, which would have required non-invasive ventilation, were avoided.ResultsThirty minutes of IPV led to a significant decrease in respiratory rate, an increase in PaO2 and a decrease in PaCO2 (p < 0.05). Exacerbation worsened in 6 out of 17 patients in the control group versus 0 out of 16 in the IPV group (p < 0.05). The hospital stay was significantly shorter in the IPV group than in the control group (6.8 ± 1.0 vs. 7.9 ± 1.3 days, p < 0.05).ConclusionIPV is a safe technique and may prevent further deterioration in patients with acute exacerbations of COPD with mild respiratory acidosis.

Control and Outcome of a Large Outbreak of Colonization and Infection with Glycopeptide- Intermediate Staphylococcus aureus in an Intensive Care Unit

BACKGROUND Glycopeptide-intermediate Staphylococcus aureus (GISA) is emerging as a cause of nosocomial infection and outbreaks of infection and colonization in intensive care units (ICUs). We describe an outbreak of GISA colonization/infection and the ensuing control measures in an ICU and investigate outcomes of the affected patients. METHODS We describe an outbreak of GISA colonization and infection that affected 21 patients in a medical ICU at a tertiary care teaching hospital, as well as the measures taken to eradicate the GISA strain. RESULT Recognition of the outbreak was difficult. Infections, all of which were severe, were diagnosed in 11 of 21 patients. Patient isolation and barrier precautions failed when used alone. Addition of a stringent policy of restricted admissions, twice daily environmental cleaning, and implementation of hand decontamination with a hydroalcoholic solution led to outbreak termination. This was associated with increases in workload, despite a marked decrease in the number of admissions. CONCLUSION This first description of a large outbreak of GISA colonization and infection underlines the importance of routine GISA-strain detection when methicillin-resistant S. aureus is isolated. Outbreak control may be difficult to achieve.

Prognostic impact of high-flow nasal cannula oxygen supply in an ICU patient with pulmonary fibrosis complicated by acute respiratory failure

Dear Editor, Pulmonary fibrosis (PF) complicated by acute respiratory failure (ARF) requiring ventilatory support has a poor prognosis, challenging the opportunity for intensive care unit (ICU) admission [1]. A new device called a high-flow nasal cannula (HFNC) is used increasingly in hypoxemic ARF [2]. We report the case of a patient who was admitted with PF-related ARF and received HFNC oxygen during his ICU stay. A 73-year-old man was admitted to the emergency department with subfebrile ARF in the context of chronic ischemic and valvular myocardiopathy treated routinely with trinitrine, spironolactone, bisoprolol and lisinopril. Amiodarone had been introduced 1 month previously. Oxygen therapy (10 l/min) with a reservoir mask was started, and transthoracic echocardiography rapidly eliminated a cardiac origin of the diffuse alveolo-interstitial infiltrate. Antibiotic treatment was introduced, but he was transferred to the ICU after deterioration of his respiratory status. His respiratory rate fluctuated between 25 and 30 breaths/min despite 15 l/min oxygen therapy. Arterial blood gas analysis revealed a PaO2 of 55 mmHg without respiratory acidosis. HFNC (OptiflowTM system; Fisher and Paykel Healthcare Ltd., Auckland, New Zealand) was introduced with an air/oxygen blender at 40 l/min and 80% FiO2. His PaO2 improved to 82 mmHg. Thoracic computed tomography revealed PF. The recent introduction of amiodarone was considered to be responsible for the PF as no other alternative etiology could be identified. As no improvement was observed after the introduction of 2 mg/kg corticosteroids on day 5 (D5), cyclophosphamide (600 mg/m) was administered on D12. The change in PaO2/FiO2 ratio over time is shown in Fig. 1. It was decided to withhold invasive ventilation on D22, and palliative care was initiated; HFNC oxygen was continued. Cyclophosphamide administration was repeated on D26. Ten days later, his PaO2/FiO2 ratio and radiographic infiltrates had improved so dramatically that the withhold order was cancelled (Fig. 1). HFNC oxygen was stopped. The patient was discharged from the ICU on D46 with 4 l/min nasal oxygen and returned home 2 weeks later. He died 3 months later with homebased palliative care. The prognosis of acute exacerbation of PF is extremely poor, particularly if ventilatory support is required (in-hospital mortality up to 87%) [1]. The few survivors all have a specific (diagnosis [3] or surgical procedure-related ARF [4]) or reversible cause [1]. In other cases, it has been suggested that mechanical ventilation is futile and that palliative care should be initiated promptly [1, 4]. Non-invasive means of providing oxygen can then be proposed until patients with potentially reversible causes of ARF are identified. We report the exceptional case of an elderly patient who improved only 1 month after ICU admission. Oxygen was first provided by noninvasive ventilation, but this was poorly tolerated [2] as was high oxygen supply with a reservoir mask. HFNC promotes comfort (in part by improving the heating and

Physiologic Effects of High-Flow Nasal Cannula Oxygen in Critical Care Subjects

INTRODUCTION: High-flow nasal cannula (HFNC) can deliver heated and humidified gas (up to 100% oxygen) at a maximum flow of 60 L/min via nasal prongs or cannula. The aim of this study was to assess the short-term physiologic effects of HFNC. Inspiratory muscle effort, gas exchange, dyspnea score, and comfort were evaluated. METHODS: Twelve subjects admitted to the ICU for acute hypoxemic respiratory failure were prospectively included. Four study sessions were performed. The first session consisted of oxygen therapy given through a high-FIO2, non-rebreathing face mask. Recordings were then obtained during periods of HFNC and CPAP at 5 cm H2O in random order, and final measurements were performed during oxygen therapy delivered via a face mask. Each of these 4 periods lasted ∼20 min. RESULTS: Esophageal pressure signals, breathing pattern, gas exchange, comfort, and dyspnea were measured. Compared with the first session, HFNC reduced inspiratory effort (pressure-time product of 156.0 [119.2–194.4] cm H2O × s/min vs 204.2 [149.6–324.7] cm H2O × s/min, P < .01) and breathing frequency (P < .01). No significant differences were observed between HFNC and CPAP for inspiratory effort and breathing frequency. Compared with the first session, PaO2/FIO2 increased significantly with HFNC (167 [157–184] mm Hg vs 156 [110–171] mm Hg, P < .01). CPAP produced significantly greater PaO2/FIO2 improvement than did HFNC. Dyspnea improved with HFNC and CPAP, but this improvement was not significant. Subject comfort was not different across the 4 sessions. CONCLUSIONS: Compared with conventional oxygen therapy, HFNC improved inspiratory effort and oxygenation. In subjects with acute hypoxemic respiratory failure, HFNC is an alternative to conventional oxygen therapy. (ClinicalTrials.gov registration NCT01056952.)

Heat and moisture exchangers in mechanically ventilated intensive care unit patients: a plea for an independent assessment of their performance.

ObjectiveTo determine whether use of a hygroscopic and hydrophobic heat and moisture exchanger (HME) for 7 days without change affects its efficiency in long-term, mechanically ventilated, chronic obstructive pulmonary disease (COPD) patients. DesignProspective, randomized, controlled clinical study comparing two combined HMEs. SettingMedical intensive care unit at a university teaching hospital. PatientsLong-term, mechanically ventilated, COPD patients compared with non-COPD patients. InterventionsIn the first part of the study, COPD patients were studied with the Hygroster HME changed once a week. For the second part, the Hygroster was assessed in non-COPD patients and compared with the Hygrobac HME used in COPD and non-COPD patients for 1 wk without change. Devices could be changed if hygrometric measurements indicated insufficient humidity delivery. Measurements and Main ResultsDaily measurements were recorded for inspired gas temperature and relative and absolute humidity. Ventilatory variables, clinical indicators of efficient humidification, were also recorded. No tracheal tube occlusion occurred. However, contrary to the manufacturer advertisement, the Hygroster experienced surprisingly low values for absolute humidity in both COPD and non-COPD patients. Such events did not occur with the Hygrobac. Absolute humidity with the Hygroster was constantly and significantly lower during the 7-day study period than with the Hygrobac. Absolute humidity measured in COPD patients was identical to that measured in the rest of the study population with both HMEs. ConclusionsManufacturer specifications and bedside measurements of absolute humidity differed considerably for the Hygroster, which in certain instances did not achieve efficient humidification in both COPD and non-COPD patients. This did not occur with the Hygrobac, which performed well throughout the 7-day period in both COPD and non-COPD patients. Our results speak for independent and in vivo evaluation of HMEs.

Central or Peripheral Catheters for Initial Venous Access of ICU Patients: A Randomized Controlled Trial

Objectives:The vast majority of ICU patients require some form of venous access. There are no evidenced-based guidelines concerning the use of either central or peripheral venous catheters, despite very different complications. It remains unknown which to insert in ICU patients. We investigated the rate of catheter-related insertion or maintenance complications in two strategies: one favoring the central venous catheters and the other peripheral venous catheters. Design:Multicenter, controlled, parallel-group, open-label randomized trial. Setting:Three French ICUs. Patients:Adult ICU patients with equal central or peripheral venous access requirement. Intervention:Patients were randomized to receive central venous catheters or peripheral venous catheters as initial venous access. Measurements and Results:The primary endpoint was the rate of major catheter-related complications within 28 days. Secondary endpoints were the rate of minor catheter-related complications and a composite score-assessing staff utilization and time spent to manage catheter insertions. Analysis was intention to treat. We randomly assigned 135 patients to receive a central venous catheter and 128 patients to receive a peripheral venous catheter. Major catheter-related complications were greater in the peripheral venous catheter than in the central venous catheter group (133 vs 87, respectively, p = 0.02) although none of those was life threatening. Minor catheter-related complications were 201 with central venous catheters and 248 with peripheral venous catheters (p = 0.06). 46% (60/128) patients were managed throughout their ICU stay with peripheral venous catheters only. There were significantly more peripheral venous catheter-related complications per patient in patients managed solely with peripheral venous catheter than in patients that received peripheral venous catheter and at least one central venous catheter: 1.92 (121/63) versus 1.13 (226/200), p < 0.005. There was no difference in central venous catheter-related complications per patient between patients initially randomized to peripheral venous catheters but subsequently crossed-over to central venous catheter and patients randomized to the central venous catheter group. Kaplan–Meier estimates of survival probability did not differ between the two groups. Conclusion:In ICU patients with equal central or peripheral venous access requirement, central venous catheters should preferably be inserted: a strategy associated with less major complications.

Long-term mechanical ventilation with hygroscopic heat and moisture exchangers used for 48 hours: a prospective clinical, hygrometric, and bacteriologic study.

ObjectiveTo determine whether use of a hygroscopic heat and moisture exchanger (HME) for 48 hrs without change affects its efficiency and the level of bacterial colonization in long-term mechanically ventilated medical intensive care unit patients. DesignProspective, randomized clinical study evaluating two hygroscopic HMEs. SettingMedical intensive care unit at a university teaching hospital. PatientsLong-term mechanically ventilated medical intensive care unit patients, including chronic obstructive pulmonary disease patients. InterventionsPatients were randomly allocated to one of the two HMEs studied (Hygrolife and EdithFlex) and changed every 48 hrs. Devices in both groups could be changed if hygrometric measurements indicated insufficient humidity delivery. Measurements and Main ResultsDaily measurements of inspired gas temperature and relative and absolute humidity. In addition, cultures of tracheal aspirations and both patient and ventilator sides of the device were performed after 48 hrs of use. Ventilatory variables and clinical indicators of efficient humidification were also recorded. Prolonged use of both HMEs was safe and efficient (no tracheal tube occlusion occurred). Mean duration of mechanical ventilation was 20 days. Both clinical indicators and hygrometric measurements showed that both devices performed well during 48 hrs. Absolute humidity with EdithFlex was significantly higher on day 0 and day 1 than with Hygrolife. Absolute humidity measured in chronic obstructive pulmonary disease patients was identical to that measured in the rest of the study population. Tracheal colonization and HME colonization were similar with both HMEs. Bacterial contamination of the ventilator side of both devices was markedly low. ConclusionsThese two purely hygroscopic HMEs provided safe and efficient humidification during a 48-hr period of use in long-term mechanically ventilated medical intensive care unit patients, including chronic obstructive pulmonary disease patients. In addition, they maintained ventilatory circuits clean, despite the absence of filtering media. The cost of mechanical ventilation is consequently reduced.

Pseudomonas aeruginosa acquisition on an intensive care unit: relationship between antibiotic selective pressure and patients' environment

IntroductionThe purpose of this study was to investigate the relationship among Pseudomonas aeruginosa acquisition on the intensive care unit (ICU), environmental contamination and antibiotic selective pressure against P. aeruginosa.MethodsAn open, prospective cohort study was carried out in a 16-bed medical ICU where P. aeruginosa was endemic. Over a six-month period, all patients without P. aeruginosa on admission and with a length of stay >72 h were included. Throat, nasal, rectal, sputum and urine samples were taken on admission and at weekly intervals and screened for P. aeruginosa. All antibiotic treatments were recorded daily. Environmental analysis included weekly tap water specimen culture and the presence of other patients colonized with P. aeruginosa.ResultsA total of 126 patients were included, comprising 1,345 patient-days. Antibiotics were given to 106 patients (antibiotic selective pressure for P. aeruginosa in 39). P. aeruginosa was acquired by 20 patients (16%) and was isolated from 164/536 environmental samples (31%). Two conditions were independently associated with P. aeruginosa acquisition by multivariate analysis: (i) patients receiving ≥3 days of antibiotic selective pressure together with at least one colonized patient on the same ward on the previous day (odds ratio (OR) = 10.3 ((% confidence interval (CI): 1.8 to 57.4); P = 0.01); and (ii) presence of an invasive device (OR = 7.7 (95% CI: 2.3 to 25.7); P = 0.001).ConclusionsSpecific interaction between both patient colonization pressure and selective antibiotic pressure is the most relevant factor for P. aeruginosa acquisition on an ICU. This suggests that combined efforts are needed against both factors to decrease colonization with P. aeruginosa.

Ethanol Lock and Risk of Hemodialysis Catheter Infection in Critically Ill Patients. A Randomized Controlled Trial

RATIONALE Ethanol rapidly eradicated experimental biofilm. Clinical studies of ethanol lock to prevent catheter-related infections (CRIs) suggest preventive efficacy. No such studies have been done in intensive care units (ICU). OBJECTIVES To determine whether ethanol lock decreases the risk of major CRI in patients with short-term dialysis catheters (DCs). METHODS A randomized, double-blind, placebo-controlled trial was performed in 16 ICUs in seven university hospitals and one general hospital in France between June 2009 and December 2011. Adults with insertion of a nontunneled, nonantimicrobial-impregnated double-lumen DC for an expected duration greater than 48 hours, to perform renal-replacement therapy or plasma exchange, were randomly allocated (1:1) to receive a 2-minute catheter lock with either 60% wt/wt ethanol solution (ethanol group) or 0.9% saline solution (control group) at the end of DC insertion and after each renal-replacement therapy or plasma exchange session. The main outcome was major CRI defined as either catheter-related clinical sepsis without bloodstream infection or catheter-related bloodstream infection during the ICU stay. MEASUREMENTS AND MAIN RESULTS The intent-to-treat analysis included 1,460 patients (2,172 catheters, 12,944 catheter-days, and 8,442 study locks). Median DC duration was 4 days (interquartile range, 2-8) and was similar in both groups. Major CRI incidence did not differ between the ethanol and control groups (3.83 vs. 2.64 per 1,000 catheter-days, respectively; hazard ratio, 1.55; 95% confidence interval, 0.83-2.87; P = 0.17). No significant differences occurred for catheter colonization (P = 0.57) or catheter-related bloodstream infection (P = 0.99). CONCLUSIONS A 2-minute ethanol lock does not decrease the frequency of infection of DCs in ICU patients. Clinical trial registered with www.clinicaltrials.gov (NCT 00875069).