Rosario Urbino

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.

Extracorporeal Co2 removal in hypercapnic patients at risk of noninvasive ventilation failure: a matched cohort study with historical control.

Objectives:To assess efficacy and safety of noninvasive ventilation-plus-extracorporeal Co2 removal in comparison to noninvasive ventilation-only to prevent endotracheal intubation patients with acute hypercapnic respiratory failure at risk of failing noninvasive ventilation. Design:Matched cohort study with historical control. Setting:Two academic Italian ICUs. Patients:Patients treated with noninvasive ventilation for acute hypercapnic respiratory failure due to exacerbation of chronic obstructive pulmonary disease (May 2011 to November 2013). Interventions:Extracorporeal CO2 removal was added to noninvasive ventilation when noninvasive ventilation was at risk of failure (arterial pH ⩽ 7.30 with arterial PCO2 > 20% of baseline, and respiratory rate ≥ 30 breaths/min or use of accessory muscles/paradoxical abdominal movements). The noninvasive ventilation-only group was created applying the genetic matching technique (GenMatch) on a dataset including patients enrolled in two previous studies. Exclusion criteria for both groups were mean arterial pressure less than 60 mm Hg, contraindications to anticoagulation, body weight greater than 120 kg, contraindication to continuation of active treatment, and failure to obtain consent. Measurements and Main Results:Primary endpoint was the cumulative prevalence of endotracheal intubation. Twenty-five patients were included in the noninvasive ventilation-plus-extracorporeal CO2 removal group. The GenMatch identified 21 patients for the noninvasive ventilation-only group. Risk of being intubated was three times higher in patients treated with noninvasive ventilation-only than in patients treated with noninvasive ventilation-plus-extracorporeal CO2 removal (hazard ratio, 0.27; 95% CI, 0.07–0.98; p = 0.047). Intubation rate in noninvasive ventilation-plus-extracorporeal CO2 removal was 12% (95% CI, 2.5–31.2) and in noninvasive ventilation-only was 33% (95% CI, 14.6–57.0), but the difference was not statistically different (p = 0.1495). Thirteen patients (52%) experienced adverse events related to extracorporeal CO2 removal. Bleeding episodes were observed in three patients, and one patient experienced vein perforation. Malfunctioning of the system caused all other adverse events. Conclusions:These data provide the rationale for future randomized clinical trials that are required to validate extracorporeal CO2 removal in patients with hypercapnic respiratory failure and respiratory acidosis nonresponsive to noninvasive ventilation.

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.

Development and validation of a new UPLC-PDA method to quantify linezolid in plasma and in dried plasma spots

Linezolid is an oxazolidinone antibiotic used for the treatment of pneumonia and uncomplicated and complicated skin and soft tissues infections caused by Gram positive bacteria. It is also used as second line agent in multi-drug resistant tuberculosis. Therapeutic drug monitoring (TDM) of linezolid represents a valid tool in clinical practice to optimize therapy, especially in critically ill patients. Spreading of TDM is mainly limited by high costs shipment and lack of laboratories that offer a TDM service. To overcome these problems, the use of dried plasma spots or dried blood spots is increasing. The aim of this work was to develop and validate a new chromatographic method to analyze linezolid in plasma and in dried plasma spots and to evaluate the correlation between the two extraction methods. Linezolid extraction from plasma and from dried plasma spots was obtained using acetonitrile. Quinoxaline was used as internal standard. Analysis was performed by an ultra performance liquid chromatography (UPLC) system coupled with photo diode array (PDA) detector, at 254nm. Both analytical methods were linear (r(2)>0.999) over the calibration range of 30-0.117mg/L. Limit of quantification and limit of detection were 0.117mg/L and 0.058mg/L, respectively. Intra and inter-day precision (R.S.D.%) and accuracy (%) were <15%. Long term stability of linezolid in dried plasma spots showed absence of degradation at room temperature (20-25°C) and at 4°C, for at least one month. Linear regression analysis confirmed that the two methods of extraction have good correlation. Thus they are suited for TDM of linezolid and for pharmacokinetic studies.

Helmet Ventilation for Acute Respiratory Failure and Nasal Skin Breakdown in Neuromuscular Disorders

Noninvasive ventilation (NIV) has been widely used to decrease the complications associated with tracheal intubation in mechanically ventilated patients with neuromuscular diseases in acute respiratory failure. However, nasal ulcerations might occur when masks are used as an interface. Helmet ventilation is a possible option in this case. We describe two patients with acute respiratory failure due to Duchenne muscular dystrophy who developed nasal bridge skin necrosis during NIV. Helmet pressure support ventilation caused significant patient-ventilator asynchrony, leading to NIV intolerance. Thus, biphasic positive airway pressure delivered by helmet was applied, which improved gas exchange and patient-ventilator interaction, allowing successful NIV.

A(H1N1)pdm09 hemagglutinin D222G and D222N variants are frequently harbored by patients requiring extracorporeal membrane oxygenation and advanced respiratory assistance for severe A(H1N1)pdm09 infection

In patients with A(H1N1)pdm09 infection, severe lung involvement requiring admission to intensive care units (ICU) has been reported. Mutations at the hemagglutinin (HA) receptor binding site (RBS) have been associated with increased virulence and disease severity, representing a potential marker of critical illness.

Pharmacokinetics of high dosage of linezolid in two morbidly obese patients

Sir, Obesity represents a major burden on healthcare as an independent risk factor for mortality in infected patients and its association with comorbidities. Adequate antimicrobial exposure is essential for treatment success, but there are few published data on the pharmacokinetics (PK) of antibiotics in obesity. Furthermore, the degree of alteration depends on several factors: degree of obesity, comorbidities and pharmacological characteristics of the drugs. In addition, the volume of distribution (V) may vary according to the amount of adipose tissue and the lipophilic properties of the antibiotic, resulting in lower serum concentrations. Linezolid is active against Gram-positive bacteria used for skin and lung infections and is a highly lipophilic molecule with a high rate of penetration into tissues. Canut et al. proposed as a PK index predictive of efficacy an AUC/MIC .100 (where AUC1⁄4area under the antimicrobial concentration–time curve for 24 h). The achievement of a Cmin ≥2 mg/L and/or AUC24 .160–200 mg.h/L was proposed as a theoretical threshold to ensure efficacy. Data reported so far show significantly lower concentrations with standard doses of linezolid in obese patients. We report here the main PK parameters in two morbidly obese patients, as defined by BMI, receiving a higher dosage of linezolid. Patient 1 was a male ,50 years old with a BMI of 72 kg/m admitted to the ICU for community-acquired pneumonia with severe sepsis. He had hypoxaemic respiratory failure and later developed methicillin-resistant Staphylococcus epidermidis bloodstream infection (BSI) with a linezolid MIC of 2 mg/L. Patient 2 was a male .60 years old with a BMI of 66 kg/m and acute hypercapnic respiratory failure, admitted to the ICU with a diagnosis of healthcare-associated pneumonia and septic shock. Bronchoalveolar lavage identified an MRSA with a linezolid MIC of 1 mg/L. Plasma concentrations of linezolid were studied at steadystate with a dose of 600 mg every 8 h intravenously by 1 h infusion. The AUC of daily (AUC0 – 24) plasma concentrations was calculated with blood samples collected before (time 0) and at 2, 4, 6 and 8 h after intravenous administration. The Cmin was defined as the concentration before the administration and the maximum plasma concentration (Cmax) as the concentration at the end of the infusion. Linezolid was determined in plasma by a UPLC–photodiode array method. PK data were analysed using Kinetica software (Thermo Scientific, Waltham, MA, USA). AUC0–24 was calculated as 3×AUC0–8. Informed consent was waived due to the clinical need for monitoring plasma levels. The main linezolid PK parameters for Patient 1 were as follows: Cmax 4.83 mg/L, Cmin 0.88 mg/L, AUC0 – 24 55.05 mg.h/L, half-life (t1/2) 3.01 h, clearance (CL) 32.70 L/h, V 141.6 L and 0.51 L/kg, AUC/MIC (MIC1⁄41 mg/L) 55.05 and AUC/MIC (MIC1⁄42 mg/L) 27.52. The main linezolid PK parameters for Patient 2 were as follows: Cmax 15.54 mg/L, Cmin 11.89 mg/L, AUC0 – 24 335.69 mg.h/L, t1/2 10.39 h, CL 5.40 L/h, V 80.98 L and 0.45 L/kg, AUC/MIC (MIC1⁄41 mg/L) 335.69 and AUC/MIC (MIC1⁄42 mg/L) 167.50. See Figure 1. There were satisfactory Cmax and Cmin only in Patient 2, whereas in Patient 1 there was an increased CL and reduced AUC. Since the PK/pharmacodynamic parameter of importance for linezolid activity is the AUC/MIC ratio, assessing changes in AUC exposure by body size is of paramount importance. Only Patient 2 had satisfactory values of AUC and AUC/MIC. Furthermore, since linezolid PK is not related to renal function, the creatinine clearance values of .120 and 40 mL/min in Patients 1 and 2, respectively, are not helpful in understanding the alteration of plasma clearance. Moreover, the observation of higher V (141.6 and 80.9 L in Patients 1 and 2, respectively, when compared with healthy volunteers (52 L) confirms the suggestion of a relationship between weight and V in determining a significant decrease of plasma exposure. Taken together, these data suggest that linezolid PK may be strongly influenced by the degree of obesity and standard doses are not sufficient, further noting that linezolid undergoes slow non-enzymatic oxidation mediated by ubiquitous reactive species in vivo.

Effects of dexmedetomidine and propofol on patient-ventilator interaction in difficult-to-wean, mechanically ventilated patients: a prospective, open-label, randomised, multicentre study

BackgroundDexmedetomidine can be used for sedation of mechanically ventilated patients and has minor respiratory effects. The aim of this study was to compare the incidence of patient-ventilator dyssynchronies during sedation with dexmedetomidine or propofol.MethodsWe conducted a multicentre, prospective, open-label, randomised clinical trial, comparing dexmedetomidine with standard propofol sedation at three intensive care units of university hospitals in Italy. Twenty difficult-to-wean patients for whom the first weaning trial had failed and who were on pressure support ventilation were randomised to receive sedation with either dexmedetomidine or propofol at a similar level of sedation (Richmond Agitation-Sedation Scale [RASS] score +1 to −2). The asynchrony index (AI) was calculated using tracings of airflow, airway pressure and electrical activity of the diaphragm sampled at 0, 0.5, 1, 2, 6, 12, 18 and 24 h.ResultsThe mean AI was lower with dexmedetomidine than with propofol from 2 h onwards, although the two groups significantly differed only at 12 h (2.68 % vs 9.10 %, p < 0.05). No further difference was observed at 18 and 24 h.ConclusionsWhen sedation with propofol and dexmedetomidine was compared at similar RASS scores of patients in whom first weaning trial had failed, the AI was lower with dexmedetomidine than with propofol, and this difference was statistically significant at 12 h. These results suggest that sedation with dexmedetomidine may offer some advantages in terms of patient-ventilator synchrony.

Combination antifungal treatment of pseudomembranous tracheobronchial invasive aspergillosis: a case report.

Invasive aspergillosis (IA) is increasingly recognized in the intensive care unit (ICU), and new risk factors associated with respiratory colonization or infection by Aspergillus spp. include steroid treatment and chronic lung obstructive disease [1, 2]. In a review of 289 autopsies in the ICU, IA was the leading cause of Goldman class I discrepancy (a missed major diagnosis with major impact on patient management and survival) [3]. The epidemiology of IA indicates an increasing number of infections in immunosuppressed patients/individuals undergoing transplantation of bone marrow, hematopoietic stem cells, or organ transplantations, and those receiving intensive chemotherapy or other immunosuppressive treatments. A broad group of patients who are admitted to ICU also have some form of immunosupppression and may be susceptible to invasive mould infections. For various reasons, figures about the true incidence of IA in ICU are difficult to generate. The most important reason is the difficulty encountered in making a definite diagnosis of IA (lack of sensitivity and specificity with regard to culture and radiology) [4]. Recently, galactomannan (GM) in bronchoalveolar lavage (BAL) fluid appears to be a promising tool for early diagnosis in non-neutropenic critically ill patients and has been associated in proven cases with sensitivity and specificity of 88 and 87%, respectively [5]. Pseudomembranous and obstructive Aspergillus tracheobronchitis are still considered to have a fatal outcome and have been reported in a wide variety of patients [6]. There has been only one report in a patient with diabetes which was treated by deoxycholate amphotericin B (AmB) and subsequent addition of oral itraconazole [7]. In this paper, we report a pseudomembranous and obstructive tracheobronchitis in a diabetic patient successfully treated with caspofungin and AmB.