Chiara Faggiano

Tidal volume lower than 6 ml/kg enhances lung protection: role of extracorporeal carbon dioxide removal.

Background:Tidal hyperinflation may occur in patients with acute respiratory distress syndrome who are ventilated with a tidal volume (VT) of 6 ml/kg of predicted body weight develop a plateau pressure (PPLAT) of 28 ≤ PPLAT ≤ 30 cm H2O. The authors verified whether VT lower than 6 ml/kg may enhance lung protection and that consequent respiratory acidosis may be managed by extracorporeal carbon dioxide removal. Methods:PPLAT, lung morphology computed tomography, and pulmonary inflammatory cytokines (bronchoalveolar lavage) were assessed in 32 patients ventilated with a VT of 6 ml/kg. Data are provided as mean ± SD or median and interquartile (25th and 75th percentile) range. In patients with 28 ≤ PPLAT ≤ 30 cm H2O (n = 10), VT was reduced from 6.3 ± 0.2 to 4.2 ± 0.3 ml/kg, and PPLAT decreased from 29.1 ± 1.2 to 25.0 ± 1.2 cm H2O (P < 0.001); consequent respiratory acidosis (Paco2 from 48.4 ± 8.7 to 73.6 ± 11.1 mmHg and pH from 7.36 ± 0.03 to 7.20 ± 0.02; P < 0.001) was managed by extracorporeal carbon dioxide removal. Lung function, morphology, and pulmonary inflammatory cytokines were also assessed after 72 h. Results:Extracorporeal assist normalized Paco2 (50.4 ± 8.2 mmHg) and pH (7.32 ± 0.03) and allowed use of VT lower than 6 ml/kg for 144 (84–168) h. The improvement of morphological markers of lung protection and the reduction of pulmonary cytokines concentration (P < 0.01) were observed after 72 h of ventilation with VT lower than 6 ml/kg. No patient-related complications were observed. Conclusions:VT lower than 6 ml/Kg enhanced lung protection. Respiratory acidosis consequent to low VT ventilation was safely and efficiently managed by extracorporeal carbon dioxide removal.

Early vs late tracheotomy for prevention of pneumonia in mechanically ventilated adult ICU patients: a randomized controlled trial.

CONTEXT Tracheotomy is used to replace endotracheal intubation in patients requiring prolonged ventilation; however, there is considerable variability in the time considered optimal for performing tracheotomy. This is of clinical importance because timing is a key criterion for performing a tracheotomy and patients who receive one require a large amount of health care resources. OBJECTIVE To determine the effectiveness of early tracheotomy (after 6-8 days of laryngeal intubation) compared with late tracheotomy (after 13-15 days of laryngeal intubation) in reducing the incidence of pneumonia and increasing the number of ventilator-free and intensive care unit (ICU)-free days. DESIGN, SETTING, AND PATIENTS Randomized controlled trial performed in 12 Italian ICUs from June 2004 to June 2008 of 600 adult patients enrolled without lung infection, who had been ventilated for 24 hours, had a Simplified Acute Physiology Score II between 35 and 65, and had a sequential organ failure assessment score of 5 or greater. INTERVENTION Patients who had worsening of respiratory conditions, unchanged or worse sequential organ failure assessment score, and no pneumonia 48 hours after inclusion were randomized to early tracheotomy (n = 209; 145 received tracheotomy) or late tracheotomy (n = 210; 119 received tracheotomy). MAIN OUTCOME MEASURES The primary endpoint was incidence of ventilator-associated pneumonia; secondary endpoints during the 28 days immediately following randomization were number of ventilator-free days, number of ICU-free days, and number of patients in each group who were still alive. RESULTS Ventilator-associated pneumonia was observed in 30 patients in the early tracheotomy group (14%; 95% confidence interval [CI], 10%-19%) and in 44 patients in the late tracheotomy group (21%; 95% CI, 15%-26%) (P = .07). During the 28 days immediately following randomization, the hazard ratio of developing ventilator-associated pneumonia was 0.66 (95% CI, 0.42-1.04), remaining connected to the ventilator was 0.70 (95% CI, 0.56-0.87), remaining in the ICU was 0.73 (95% CI, 0.55-0.97), and dying was 0.80 (95% CI, 0.56-1.15). CONCLUSION Among mechanically ventilated adult ICU patients, early tracheotomy compared with late tracheotomy did not result in statistically significant improvement in incidence of ventilator-associated pneumonia. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00262431.

Accuracy of plateau pressure and stress index to identify injurious ventilation in patients with acute respiratory distress syndrome.

Background:Guidelines suggest a plateau pressure (PPLAT) of 30 cm H2O or less for patients with acute respiratory distress syndrome, but ventilation may still be injurious despite adhering to this guideline. The shape of the curve plotting airway pressure versus time (STRESS INDEX) may identify injurious ventilation. The authors assessed accuracy of PPLAT and STRESS INDEX to identify morphological indexes of injurious ventilation. Methods:Indexes of lung aeration (computerized tomography) associated with injurious ventilation were used as a “reference standard.” Threshold values of PPLAT and STRESS INDEX were determined assessing the receiver-operating characteristics (“training set,” N = 30). Accuracy of these values was assessed in a second group of patients (“validation set,” N = 20). PPLAT and STRESS INDEX were partitioned between respiratory system (Pplat,Rs and STRESS INDEX,RS) and lung (PPLAT,L and STRESS INDEX,L; esophageal pressure; “physiological set,” N = 50). Results:Sensitivity and specificity of PPLAT of greater than 30 cm H2O were 0.06 (95% CI, 0.002–0.30) and 1.0 (95% CI, 0.87–1.00). PPLAT of greater than 25 cm H2O and a STRESS INDEX of greater than 1.05 best identified morphological markers of injurious ventilation. Sensitivity and specificity of these values were 0.75 (95% CI, 0.35–0.97) and 0.75 (95% CI, 0.43–0.95) for PPLAT greater than 25 cm H2O versus 0.88 (95% CI, 0.47–1.00) and 0.50 (95% CI, 0.21–0.79) for STRESS INDEX greater than 1.05. Pplat,Rs did not correlate with PPLAT,L (R2 = 0.0099); STRESS INDEX,RS and STRESS INDEX,L were correlated (R2 = 0.762). Conclusions:The best threshold values for discriminating morphological indexes associated with injurious ventilation were Pplat,Rs greater than 25 cm H2O and STRESS INDEX,RS greater than 1.05. Although a substantial discrepancy between Pplat,Rs and PPLAT,L occurs, STRESS INDEX,RS reflects STRESS INDEX,L.

Extracorporeal membrane oxygenation in adult patients with acute respiratory distress syndrome.

Purpose of reviewTo examine the role of extracorporeal membrane oxygenation (ECMO) as potential therapeutic option for severe cases of acute respiratory distress syndrome (ARDS). Recent findingsThe use of ECMO to treat acute respiratory failure dramatically increased. Factors that may explain this increase in the use of ECMO are H1N1 pandemic influenza, results of recent clinical trials and not lastly the technological development and consequently the commercial pressure of the industry. Under these circumstances, clinicians urgently need clinical trials and formal indication, contraindication and rules for implementation to provide reproducible results. SummaryGuidelines from the Extracorporeal Life Support Organization still indicate ECMO for acute severe pulmonary failure potentially reversible and unresponsive to conventional management. The new definition of ARDS (Berlin definition) addresses clinicians to the best treatment options in respect of the severity of illness and allocates ECMO as a potential therapeutic option for patients with severe ARDS and a P/F ratio lower than 100 and proposed that the indication of ECMO may be shifted from the treatment of choice for refractory hypoxemia to the treatment of choice to minimize ventilator-induced lung injury.

Tracheostomy in Mechanical Ventilation

Airway access for mechanical ventilation (MV) can be provided either by orotracheal intubation (OTI) or tracheostomy tube. During episodes of acute respiratory failure, patients are commonly ventilated through an orotracheal tube that represents an easy and rapid initial placement of the airway device. OTI avoids acute surgical complications such as bleeding, nerve and posterior tracheal wall injury, and late complications such as wound infection and tracheal lumen stenosis that may emerge due to tracheostomy tube placement. Tracheostomy is often considered when MV is expected to be applied for prolonged periods or for the improvement of respiratory status, as this approach provides airway protection, facilitates access for secretion removal, improves patient comfort, and promotes progression of care in and outside the intensive care unit (ICU). The aim of this review is to assess the frequency and performance of different surgical or percutaneous dilational tracheostomy and timing and safety procedures associated with the use of fiberoptic bronchoscopy and ultrasounds. Moreover, we analyzed the performance based on National European surveys to assess the current tracheostomy practice in ICUs.

Ventilatory Management During Normothermic Ex Vivo Lung Perfusion: Effects on Clinical Outcomes.

Background During ex vivo lung perfusion (EVLP), fixed ventilator settings and monitoring of compliance are used to prevent ventilator-induced lung injury (VILI). Analysis of the airway pressure-time curve (stress index) has been proposed to assess the presence of VILI. We tested whether currently proposed ventilator settings expose lungs to VILI during EVLP and whether the stress index could identify VILI better than compliance. Methods Flow, volume, and airway opening pressure were collected continuously during EVLP. Durations of mechanical ventilation, intensive care unit (ICU) and hospital lengths of stay were recorded in lung recipients. Results Fourteen lungs underwent EVLP and were transplanted. In 5 lungs, 95 ± 2% of the stress index values were within the 0.95 to 1.05 range (protected); in the remaining nine lungs, 69 ± 1% of the values were greater than 1.05 and 15 ± 3% were less than 0.95 (nonprotected). There was a significant (P < 0.05) increase in cytokine concentrations after 4 hours of EVLP in the nonprotected lungs. Durations of mechanical ventilation, ICU, and hospital lengths of stay were shorter in recipients of protected than that of nonprotected lungs (P < 0.05). There was no correlation between compliance during EVLP and duration of mechanical ventilation or ICU and hospital lengths of stay in recipients, but the stress index during EVLP was significantly correlated with the duration of mechanical ventilation and with ICU and hospital lengths of stay (P < 0.05). Conclusions This small, preliminary study shows that ventilator settings currently proposed for EVLP may expose lungs to VILI. Use of the stress index to personalize ventilator settings needs to be tested in further clinical studies.

Protective Mechanical Ventilation in Brain Dead Organ Donors

Mechanical ventilation is the procedure to assist or replace spontaneous breathing in all clinical conditions where the function of the lungs to remove carbon dioxide and supply oxygen is compromised. Originally developed to manage the respiratory consequences of anesthesia [1], the use of mechanical ventilation to manage patients with acute respiratory failure during the 1952 epidemic of poliomyelitis in Copenhagen decreased mortality from 80 to 40 % [2]. Since then mechanical ventilation became a mainstay for patients with acute respiratory failure, including patients with severe brain injury and brain dead subjects who may become potential organ donors.