Maria Vargas

Protective mechanical ventilation in the non-injured lung: review and meta-analysis.

Acute respiratory distress syndrome (ARDS) is one of the main causes of mortality in critically ill patients. Injured lungs can be protected by optimum mechanical ventilator settings, using low tidal volume (VT) values and higher positive-end expiratory pressure (PEEP); the benefits of this protective strategy on outcomes have been confirmed in several prospective randomized controlled trials (RCTs). The question is whether healthy lungs need specific protective ventilatory settings when they are at risk of injury. We performed a systematic review of the scientific literature and a meta-analysis regarding the rationale of applying protective ventilatory strategies in patients at risk of ARDS in the perioperative period and in the intensive care unit (ICU).

Tracheostomy procedures in the intensive care unit: an international survey.

IntroductionPercutaneous dilatational tracheostomy (PDT) is one of the most frequent procedures performed in the intensive care unit (ICU). PDT may add potential benefit to clinical management of critically ill patients. Despite this, no clinical guidelines are available. We sought to characterize current practice in this international survey.MethodsAn international survey, endorsed and peer reviewed by European Society of Intensive Care Medicine (ESICM), was carried out from May to October 2013. The questionnaire was accessible from the ESICM website in the ‘survey of the month’ section.Results429 physicians from 59 countries responded to this survey. Single step dilatational tracheostomy was the most used PDT in ICU. Almost 75 % of PDT’s were performed by intensive care physicians. The main indication for PDT was prolonged mechanical ventilation. Tracheostomies were most frequently performed between 7–15 days after ICU admission. Volume control mechanical ventilation, and a combination of sedation, analgesia, neuromuscular blocking agents and fiberoptic bronchoscopy were used. Surgical tracheostomy was mainly performed in ICU by ENT specialists, and was generally chosen when for patients at increased risk for difficult PDT insertion. Bleeding controlled by compression and stoma infection/inflammation were the most common intra-procedural and late complications, respectively. Informed consent for PDT was obtained in only 60 % of cases.ConclusionsThis first international picture of current practices in regard to tracheostomy insertion demonstrates considerable geographic variation in practice, suggesting a need for greater standardization of approaches to tracheostomy insertion.

Management and outcome of mechanically ventilated patients after cardiac arrest

IntroductionThe aim of this study was to describe and compare the changes in ventilator management and complications over time, as well as variables associated with 28-day hospital mortality in patients receiving mechanical ventilation (MV) after cardiac arrest.MethodsWe performed a secondary analysis of three prospective, observational multicenter studies conducted in 1998, 2004 and 2010 in 927 ICUs from 40 countries. We screened 18,302 patients receiving MV for more than 12 hours during a one-month-period. We included 812 patients receiving MV after cardiac arrest. We collected data on demographics, daily ventilator settings, complications during ventilation and outcomes. Multivariate logistic regression analysis was performed to calculate odds ratios, determining which variables within 24 hours of hospital admission were associated with 28-day hospital mortality and occurrence of acute respiratory distress syndrome (ARDS) and pneumonia acquired during ICU stay at 48 hours after admission.ResultsAmong 812 patients, 100 were included from 1998, 239 from 2004 and 473 from 2010. Ventilatory management changed over time, with decreased tidal volumes (VT) (1998: mean 8.9 (standard deviation (SD) 2) ml/kg actual body weight (ABW), 2010: 6.7 (SD 2) ml/kg ABW; 2004: 9 (SD 2.3) ml/kg predicted body weight (PBW), 2010: 7.95 (SD 1.7) ml/kg PBW) and increased positive end-expiratory pressure (PEEP) (1998: mean 3.5 (SD 3), 2010: 6.5 (SD 3); P <0.001). Patients included from 2010 had more sepsis, cardiovascular dysfunction and neurological failure, but 28-day hospital mortality was similar over time (52% in 1998, 57% in 2004 and 52% in 2010). Variables independently associated with 28-day hospital mortality were: older age, PaO2 <60 mmHg, cardiovascular dysfunction and less use of sedative agents. Higher VT, and plateau pressure with lower PEEP were associated with occurrence of ARDS and pneumonia acquired during ICU stay.ConclusionsProtective mechanical ventilation with lower VT and higher PEEP is more commonly used after cardiac arrest. The incidence of pulmonary complications decreased, while other non-respiratory organ failures increased with time. The application of protective mechanical ventilation and the prevention of single and multiple organ failure may be considered to improve outcome in patients after cardiac arrest.

Effects of in-hospital low targeted temperature after out of hospital cardiac arrest: A systematic review with meta-analysis of randomized clinical trials.

OBJECTIVE We performed this systematic review to evaluate the effectiveness of in-hospital low targeted temperature in adult patients after out of hospital cardiac arrest on survival and neurologic performance. DATA SOURCE We systematically searched MEDLINE and PUBMED from inception to April 2014. STUDY SELECTION Citations were screened for studies evaluating the effect of in-hospital low targeted temperature in patients following out of hospital cardiac arrest. DATA EXTRACTION We analyzed randomized control trials (RCTs) that included adult patients resuscitated from out of hospital cardiac arrest, reporting mortality at hospital discharge and comparing in-hospital low targeted temperature with a control group. DATA SYNTHESIS This meta-analysis included 6 RCTs and 1418 adult patients. In-hospital low targeted (low T) temperature was associated to a reduction in mortality at hospital discharge and at 6 months when compared with in-hospital targeted and not targeted temperature while there was no reduction in mortality comparing low and high targeted temperature. In patients with initial ventricular fibrillation/ventricular tachycardia rhythm of out of hospital cardiac arrest, low T was associated with a reduction in short and long-term mortality when compared with no targeted temperature while not when compared to high targeted temperature. Low T was associated with good neurologic performance at hospital discharge compared with in-hospital high or not targeted temperature. CONCLUSION In-hospital low targeted temperature (<4 °C) improved short and long-term mortality when compared to no targeted temperature. In contrast, low T did not improve outcome compared with a slightly higher targeted temperature (≈ 36 °C).

Immunomodulatory Effect of Continuous Venovenous Hemofiltration during Sepsis: Preliminary Data

Introduction. Severe sepsis and septic shock are the primary causes of multiple organ dysfunction syndrome (MODS), which is the most frequent cause of death in intensive care unit patients. Many pro- and anti-inflammatory mediators, such as interleukin-6 (IL-6), play a strategic role in septic syndrome. Continuous renal replacement therapy (CRRT) removes in a nonselective way pro- and anti-inflammatory mediators. Objective. To investigate the effects of continuous venovenous hemofiltration (CVVH) as an immunomodulatory treatment of sepsis in a prospective clinical study. Methods. High flux hemofiltration (Qf = 60 ml/Kg/hr) was performed for 72 hr in thirteen critically ill patients suffering from severe sepsis or septic shock with acute renal failure (ARF). IL-6 gene expression was measured by real-time PCR analysis on RNA extracted from peripheral blood mononuclear cell before beginning of treatment (T0) and after 12, 24, 48, and 72 hours (T1–4). Results. Real-time PCR analysis demonstrated in twelve patients IL-6 mRNA reduction after 12 hours of treatment and a progressive increase after 24, 48, and 72 hours. Conclusions. We suggest that an immunomodulatory effect might exist during CVVH performed in critically ill patients with severe sepsis and septic shock. Our data show that the transcriptional activity of IL-6 increases during CVVH.

Percutaneous Dilatational Tracheostomy With a Double-Lumen Endotracheal Tube

OBJECTIVE Gas exchange and airway pressures are markedly altered during percutaneous dilatational tracheostomy (PDT). A double-lumen endotracheal tube (DLET) has been developed for better airway management during PDT. The current study prospectively evaluated the in vivo feasibility, gas exchange, and airway pressures during PDT with DLET compared with a conventional endotracheal tube (ETT). METHODS According to eligibility criteria, patients were divided into a case group (those receiving PDT with DLET) and a control group (those receiving PDT with a conventional ETT). The Ciaglia single-dilator technique was used for PDT in both groups. The primary end point of this study was the feasibility of tracheostomy with DLET. The secondary end points were a comparison of gas exchange, airway pressures, minute volume, and tidal volume before, during, and after PDT performed with DLET and conventional ETT. RESULTS Ten patients meeting the inclusion criteria were assigned to each group. PDTs were performed without difficulties in nine patients in the DLET group and 10 patients in the conventional ETT group. During PDT, gas exchange, airway pressures, and minute ventilation remained more stable in the DLET group and were significantly different from those in the conventional ETT group. CONCLUSIONS PDT with DLET can be performed safely without difficulties limiting the technique. Furthermore, during PDT, the use of the DLET resulted in more stable gas exchange, airway pressures, and ventilation than PDT with a conventional ETT. TRIAL REGISTRY ClinicalTrials.gov; No.: NCT01691222; URL: www.clinicaltrials.gov.

Double lumen endotracheal tube for percutaneous tracheostomy–reply.

BACKGROUND: Percutaneous dilational tracheostomy is normally a bronchoscope-guided procedure. The insertion of a bronchoscope into an endotracheal tube (ETT) affects resistance, flow, and alveolar pressure. To improve airway management and ventilation during percutaneous tracheostomy, we developed a double lumen endotracheal tube (DLET). The aim of this in vitro study was to compare the linear constant of the Rohrer equation (K1), the nonlinear constant of the Rohrer equation (K2), the inspiratory and expiratory airway resistance, and ventilatory and airway pressures using the DLET with different standard sized ETTs. METHODS: A trachea and lung model was used to compare the DLET to ETTs with 7, 7.5, and 8 mm inner diameters with and without a bronchoscope (4.5 mm external diameter), and 4 and 5 mm inner diameter ventilation tubes (F4, F5) of a translaryngeal tracheostomy. For each device, the pressure drop across the device and the Rohrer equation linear constant (K1) and nonlinear constant (K2) were calculated during a continuous flow of 10–90 L/min, the inspiratory and expiratory airway resistance values were calculated during volume controlled mechanical ventilation, and respiratory airway pressure values were calculated during volume and pressure controlled mechanical ventilation. RESULTS: DLET had lower K2, pressure drop, and inspiratory and expiratory airway resistance compared with conventional ETTs plus fiberoptic bronchoscope. Furthermore, during mechanical ventilation, DLET had a lower value of peak pressure, mean pressure, and intrinsic PEEP than the other ETTs plus fiberoptic bronchoscope. CONCLUSIONS: Use of the DLET during percutaneous dilational tracheostomy allows fiberoptic bronchoscopy without imposing excessive airway resistance. Reduced tube resistance during this procedure may confer additional safety in what is well known to be a hazardous procedure.

Heat and moisture exchangers (HMEs) and heated humidifiers (HHs) in adult critically ill patients: a systematic review, meta-analysis and meta-regression of randomized controlled trials

BackgroundThe aims of this systematic review and meta-analysis of randomized controlled trials are to evaluate the effects of active heated humidifiers (HHs) and moisture exchangers (HMEs) in preventing artificial airway occlusion and pneumonia, and on mortality in adult critically ill patients. In addition, we planned to perform a meta-regression analysis to evaluate the relationship between the incidence of artificial airway occlusion, pneumonia and mortality and clinical features of adult critically ill patients.MethodsComputerized databases were searched for randomized controlled trials (RCTs) comparing HHs and HMEs and reporting artificial airway occlusion, pneumonia and mortality as predefined outcomes. Relative risk (RR), 95% confidence interval for each outcome and I2 were estimated for each outcome. Furthermore, weighted random-effect meta-regression analysis was performed to test the relationship between the effect size on each considered outcome and covariates.ResultsEighteen RCTs and 2442 adult critically ill patients were included in the analysis. The incidence of artificial airway occlusion (RR = 1.853; 95% CI 0.792–4.338), pneumonia (RR = 932; 95% CI 0.730–1.190) and mortality (RR = 1.023; 95% CI 0.878–1.192) were not different in patients treated with HMEs and HHs. However, in the subgroup analyses the incidence of airway occlusion was higher in HMEs compared with HHs with non-heated wire (RR = 3.776; 95% CI 1.560–9.143). According to the meta-regression, the effect size in the treatment group on artificial airway occlusion was influenced by the percentage of patients with pneumonia (β = -0.058; p = 0.027; favors HMEs in studies with high prevalence of pneumonia), and a trend was observed for an effect of the duration of mechanical ventilation (MV) (β = -0.108; p = 0.054; favors HMEs in studies with longer MV time).ConclusionsIn this meta-analysis we found no superiority of HMEs and HHs, in terms of artificial airway occlusion, pneumonia and mortality. A trend favoring HMEs was observed in studies including a high percentage of patients with pneumonia diagnosis at admission and those with prolonged MV. However, the choice of humidifiers should be made according to the clinical context, trying to avoid possible complications and reaching the appropriate performance at lower costs.

A comparison of videolaryngoscopes for tracheal intubation in predicted difficult airway: A feasibility study

BackgroundVideolaryngoscopy has become increasingly attractive for the routine management of the difficult airway. Glidescope® is well studied in the literature while imago V-Blade® is a recent videolaryngoscope. This is a feasibility study with 1:1 case-control sequential allocation comparing Imago V-Blade ® and Glidescope® in predicted difficult airway settings.MethodsTwo senior anesthesiologists with no clinical experience in video assisted intubation but previously trained in a simulated scenario, performed the endotracheal intubations with Imago V-Blade® and Glidescope®. A third experienced anesthesiologist supervised the procedures. Forty-two patients, 21 for each group, with the presence of predicted difficult airway according to the Italian guideline were included. The primary end point is the feasibility of intubation. The secondary end-points are the success to intubate in the first attempt, the intubation time, the Cormack and Lehane score view, the comparison of the intubation difficulty scale (IDS) score and the need for maneuvers to aid the endotracheal intubation comparing Imago V-Blade® and Glidescope®.ResultsThe intubation was achieved in 100% of cases in both groups. No differences were found in the first-attempt success rate (p = 0.383), intubation time (p = 0.280), Cormack and Lehane score view (p = 0.799) and IDS score (p = 0.252). Statistical differences were found in external laryngeal pressure (p = 0.005), advancement of the blade (p = 0.024) and use of increasing lifting force (p = 0.048).ConclusionsThis feasibility study showed that the intubation with the newly introduced Imago V-Blade® is feasible. Further randomized and/or non-inferiority trials are needed to evaluate the benefit of Imago V-Blade® in this procedure.Trial registrationClinicaltrials.gov NCT02897518. Retrospectively registered 25 August 2016

Unheated or No Humidification Bubble for Long-Term Nasal Low-Flow Oxygen: A Matter of Nasal Mucosa Response or Disease Progression

We have read with great interest the paper by Franchini et al published in CHEST (August 2016), which reported on a randomized clinical trial comparing the effects of dry nasal low-flow oxygen (NLFO) and cold bubble humidified NLFO on nasal mucociliary clearance (MCC), mucus properties, inflammation, and symptoms in subjects with chronic hypoxemia requiring long-term domiciliary oxygen therapy. A few issues come to mind.