Edoardo Calderini

Patient-ventilator asynchrony during noninvasive ventilation: the role of expiratory trigger

Objective: Air leaks around the mask are very likely to occur during noninvasive ventilation, in particular when prolonged ventilatory treatment is required. It has been suggested that leaks from the mask may impair the expiratory trigger cycling mechanism when inspiratory pressure support ventilation (PSV) is used. The aim of this study was to compare the short-term effect of two different expiratory cycling mechanisms (time-cycled vs flow-cycled) during noninvasive inspiratory pressure support ventilation (NIPSV) on patient-ventilator synchronisation in severe hypoxemic respiratory failure. Study population: Six patients with acute lung injury (ALI) due to acquired immunodeficiency syndrome (AIDS)-related opportunistic pneumonia were enrolled in the protocol. Intervention: Each subject was first studied during spontaneous breathing with a Venturi oxygen mask (SB) and successively submitted to a randomly assigned 20 ′ conventional flow-cycling (NIPSVfc) or time-cycling inspiratory pressure support ventilation (NIPSVtc). The pre-set parameters were: inspiratory pressure of 10 cm H2O, PEEP of 5 cm H2O for the same inspired oxygen fraction as during SB. A tight fit of the mask was avoided in order to facilitate air leaks around the mask. The esophageal pressure time product (PTPes) and tidal swings (ΔPes) were measured to evaluate the patients respiratory effort. A subjective “comfort score” and the difference between patient and machine respiratory rate [ΔRR(p-v)], calculated on esophageal and airway pressure curves, were used as indices of patient-machine interaction. Results: Air leaks through the mask occurred in five out of six patients. The values of PEEPi (< 1.9 cm H20) excluded significant expiratory muscle activity. NIPSVtc significantly reduced PTPes, ΔPes, and ΔRR(p-v) when compared to NIPSVfc [230 ± 41 (SE) vs 376 ± 72 cm H2O · s · min–1 ; 8 ± 2 vs 13 ± 2 cm H2O; 1 ± 1 vs 9 ± 2 br · min–1; respectively] with a concomitant significant improvement of the “comfort score”. Conclusions: In the presence of air leaks a time-cycled expiratory trigger provides a better patient-machine interaction than a flow-cycled expiratory trigger during NIPSV.

Lung and chest wall mechanics in patients with acquired immunodeficiency syndrome and severe Pneumocystis carinii pneumonia

The aim of this study was to assess the mechanical characteristics of the respiratory system in patients with acquired immune deficiency syndrome (AIDS) and acute respiratory distress syndrome (ARDS) caused by Pneumocystis carinii pneumonia (PCP). In 12 mechanically ventilated patients, total respiratory system mechanics was assessed using the technique of rapid airway occlusion during constant flow inflation, and was partitioned into lung and chest wall components using the oesophageal balloon technique. We measured interrupter resistance (Rint), which mainly reflects airway resistance, additional resistance (deltaR) due to viscoelastic behaviour and time constant inequalities, and static elastance (Est). In addition, the static inflation volume-pressure (V-P) curve was assessed. In eight patients, computed tomography scans were performed within 2 days of the assessment of respiratory mechanics. Compared to values reported in the literature for normal subjects, Est and deltaR were markedly increased in AIDS patients with PCP, whilst Rint exhibited a relatively smaller increase. These changes, which involved only the lung and airways, were mainly due to the reduction of ventilated lung units, but additional factors were involved to cause independent modifications of lung stiffness, airway calibre, and viscoelastic properties. The changes in Rint, deltaR, and Est were similar to those observed in other studies on patients with ARDS of different aetiologies. At variance with common observations in the latter patients, none of the AIDS patients with PCP exhibited an inflection point on the static inflation V-P curve, suggesting little or no alveolar recruitment during lung inflation. This finding could be related to the distinctive histopathology of Pneumocystis carinii pneumonia. Indeed, computed tomography revealed homogeneous diffuse interstitial and alveolar infiltration rather than the dense, dependent opacities observed in other studies on acute respiratory distress syndrome of different aetiologies.

Noninvasive Continuous Positive Airway Pressure in Acute Respiratory Failure: Helmet Versus Facial Mask

OBJECTIVE: Noninvasive continuous positive airway pressure (nCPAP) is applied through different interfaces to treat mild acute respiratory failure (ARF) in infants. Recently a new pediatric helmet was introduced in clinical practice to deliver nCPAP. The objective of this study was to compare the feasibility of the delivery of nCPAP by the pediatric helmet with delivery by a conventional facial mask in infants with ARF. PATIENTS AND METHODS: We conducted a single-center physiologic, randomized, controlled study with a crossover design on 20 consecutive infants with ARF. All patients received nCPAP by helmet and facial mask in random order for 90 minutes. In infants in both trials, nCPAP treatment was preceded by periods of unassisted spontaneous breathing through a Venturi mask. The primary end point was the feasibility of nCPAP administered with the 2 interfaces (helmet and facial mask). Feasibility was evaluated by the number of trial failures defined as the occurrence of 1 of the following: intolerance to the interface; persistent air leak; gas-exchange derangement; or major adverse events. nCPAP application time, number of patients who required sedation, and the type of complications with each interface were also recorded. The secondary end point was gas-exchange improvement. RESULTS: Feasibility of nCPAP delivery was enhanced by the helmet compared with the mask, as indicated by a lower number of trial failures (P < .001), less patient intolerance (P < .001), longer application time (P < .001), and reduced need for patient sedation (P < .001). For both delivery methods, no major patient complications occurred. CONCLUSIONS: The results of this current study revealed that the helmet is a feasible alternative to the facial mask for delivery of nCPAP to infants with mild ARF.

Evolution of Noninvasive Mechanical Ventilation Use: A Cohort Study among Italian PICUs

Objective: To assess how clinical practice of noninvasive ventilation has evolved in the Italian PICUs. Design: National, multicentre, retrospective, observational cohort. Setting: Thirteen Italian medical/surgical PICUs that participated in the Italian PICU Network. Patients: Seven thousand one-hundred eleven admissions of children with 0–16 years old admitted from January 1, 2011, to December 31, 2012. Interventions: None. Measurements and Main Results: Cause of respiratory failure, length and mode of noninvasive ventilation, type of interfaces, incidence of treatment failure, and outcome were recorded. Data were compared with an historical cohort of children enrolled along 6 months from November 1, 2006, to April 30, 2007, over the viral respiratory season. Seven thousand one-hundred eleven PICU admissions were analyzed, and an overall noninvasive ventilation use of 8.8% (n = 630) was observed. Among children who were admitted in the PICU without mechanical ventilation (n = 3,819), noninvasive ventilation was used in 585 patients (15.3%) with a significant increment among the three study years (from 11.6% in 2006 to 18.2% in 2012). In the endotracheally intubated group, 17.2% children received noninvasive ventilation at the end of the weaning process to avoid reintubation: 11.9% in 2006, 15.3% in 2011, and 21.6% in 2012. Noninvasive ventilation failure rate raised from 10% in 2006 to 16.1% in 2012. Conclusions: Noninvasive ventilation is increasingly and successfully used as first respiratory approach in several, but not all, Italian PICUs. The current study shows that noninvasive ventilation represents a feasible and safe technique of ventilatory assistance for the treatment of mild acute respiratory failure. Noninvasive ventilation was used as primary mode of ventilation in children with low respiratory tract infection (mainly in bronchiolitis and pneumonia), in acute on chronic respiratory failure or to prevent reintubation.

Change in pulmonary mechanics and the effect on breathing pattern of high flow oxygen therapy in stable hypercapnic COPD

We studied the effects of high flow oxygen therapy (HFOT) versus non-invasive ventilation (NIV) on inspiratory effort, as assessed by measuring transdiaphragmatic pressure, breathing pattern and gas exchange. Fourteen patients with hypercapnic COPD underwent five 30-min trials: HFOT at two flow rates, both with open and closed mouth, and NIV, applied in random order. After each trial standard oxygen therapy was reinstituted for 10 min. Compared with baseline, HFOT and NIV significantly improved breathing pattern, although to different extents, and reduced inspiratory effort; however, arterial carbon dioxide oxygen tension decreased but not significantly. These results indicate a possible role for HFOT in the long-term management of patients with stable hypercapnic COPD. Trial registration number NCT02363920.

Treatment of acute hypoxemic respiratory failure with continuous positive airway pressure delivered by a new pediatric helmet in comparison with a standard full face mask: A prospective pilot study

Objectives: To evaluate the feasibility and efficacy of continuous positive airway pressure delivered by a new pediatric helmet in comparison with a standard facial mask in infants with acute hypoxemic respiratory failure. Design: A single-center prospective case–control study. Setting: Pediatric intensive care unit in a tertiary children hospital. Patients and Interventions: Twenty consecutive infants treated with continuous positive airway pressure by a helmet matched with a control patient treated with continuous positive airway pressure by facial mask and selected by age, weight, PaO2:Fio2, and PaCO2 on pediatric intensive care unit admission. Measurements and Main Results: Feasibility was defined as the incidence of continuous positive airway pressure protocol failure secondary to 1) failure to administer continuous positive airway pressure because of intolerance to the interface; 2) deterioration in gas exchange soon after continuous positive airway pressure institution; and 3) major clinical adverse events such as pneumothorax or any hemodynamic instability related to the continuous positive airway pressure safety system devices failure. Evaluation of feasibility included also the total application time of respiratory treatment, the number of continuous positive airway pressure discontinuations/first 24 hrs. Interface-related complications included air leaks, cutaneous pressure sores, eye irritation, inhalation, and gastric distension. The 20 patients and control subjects had similar matching characteristics. Continuous positive airway pressure delivered by a helmet compared with a facial mask reduced continuous positive airway pressure trial failure rate (p = .02), increased application time (p = .001) with less discontinuations (p = .001), and was not associated with an increased rate of major adverse events, resulting in decreased air leaks (p = .04) and pressure sores (p = .002). Both continuous positive airway pressure systems resulted in early and sustained improvement in oxygenation. Conclusions: The helmet might be considered a viable and safe alternative to a standard facial mask to deliver continuous positive airway pressure in hypoxemic infants in the pediatric intensive care unit setting. In our study, the helmet allowed more prolonged application of continuous positive airway pressure compared with a facial mask, ensuring similar improvement in oxygenation without any adverse events and clinical intolerance.

What are the current indications for noninvasive ventilation in children

Purpose of review The aims of this paper are to examine the physiological rationale for noninvasive respiratory support (NRS) in children older than 1 month with acute respiratory failure, to review clinical available data and to give some practical recommendations for the safe application of NRS. Recent findings NRS is the delivery of ventilatory support without the need for an invasive airway. Two types of NRS are commonly used in the pediatric population: noninvasive continuous positive airway pressure and noninvasive positive pressure ventilation. In general, the evidence to support the use of NRS in children with acute respiratory failure is scarce. However, two randomized studies have been recently published suggesting that noninvasive positive pressure ventilation ameliorates clinical signs and gas exchange while reducing the need for endotracheal intubation. Moreover, noninvasive continuous positive airway pressure and heliox may improve clinical scores and carbon dioxide washout in infants with severe bronchiolitis, without major complications. Data from noncontrolled studies show that NRS unloads the respiratory muscles and that the helmet can be a valid alternative to a facial and/or nasal mask when noninvasive continuous positive airway pressure is administered to children in the early stage of acute respiratory failure. Summary Preliminary clinical data show that NRS is safe and effective in children with acute respiratory failure.

Continuous Positive Airway Pressure With Helmet Versus Mask in Infants With Bronchiolitis: An RCT

BACKGROUND: Noninvasive continuous positive airway pressure (CPAP) is usually applied with a nasal or facial mask to treat mild acute respiratory failure (ARF) in infants. A pediatric helmet has now been introduced in clinical practice to deliver CPAP. This study compared treatment failure rates during CPAP delivered by helmet or facial mask in infants with respiratory syncytial virus-induced ARF. METHODS: In this multicenter randomized controlled trial, 30 infants with respiratory syncytial virus-induced ARF were randomized to receive CPAP by helmet (n = 17) or facial mask (n = 13). The primary endpoint was treatment failure rate (defined as due to intolerance or need for intubation). Secondary outcomes were CPAP application time, number of patients requiring sedation, and complications with each interface. RESULTS: Compared with the facial mask, CPAP by helmet had a lower treatment failure rate due to intolerance (3/17 [17%] vs 7/13 [54%], P = .009), and fewer infants required sedation (6/17 [35%] vs 13/13 [100%], P = .023); the intubation rates were similar. In successfully treated patients, CPAP resulted in better gas exchange and breathing pattern with both interfaces. No major complications due to the interfaces occurred, but CPAP by mask had higher rates of cutaneous sores and leaks. CONCLUSIONS: These findings confirm that CPAP delivered by helmet is better tolerated than CPAP delivered by facial mask and requires less sedation. In addition, it is safe to use and free from adverse events, even in a prolonged clinical setting.

Ventilator-associated pneumonia in an Italian pediatric intensive care unit: a prospective study.

BackgroundThis study was undertaken to determine the prevalence, risk factors and outcomes associated with ventilator-associated pneumonia (VAP) in a European pediatric intensive care unit (PICU).MethodsA total of 451 children who had been mechanically ventilated in the PICU for ≥48 hours during a 3-year period were enrolled in this prospective study.ResultsIn comparison with children without VAP, 30 children (6.6%) who developed VAP had a longer PICU stay (P=0.0001) and hospital stay (P=0.0001), and a higher mortality rate (P=0.04). Logistic regression analysis showed that the need for re-intubation (P=0.0001), the presence of tracheostomy (P=0.04), and enteral feeding (P=0.02) were independent risk factors for VAP.ConclusionsA relevant proportion of intubated children develop VAP, which is closely related to invasive procedures. As VAP is associated with increased medical costs and death, multicenter studies are urgently needed to improve the therapeutic approach to VAP and VAP prevention.

EMpowerment of PArents in THe Intensive Care Questionnaire: Translation and Validation in Italian PICUs

Objectives: To translate and validate the EMpowerment of PArents in THe Intensive Care questionnaire to measure parent satisfaction and experiences in Italian PICUs. Design: Prospective, multicenter study. Setting: Four medical/surgical Italian PICUs in three tertiary hospitals. Patients: Families of children, 0–16 years old, admitted to the PICUs were invited to participate. Inclusion criteria were PICU length of stay greater than 24 hours and good comprehension of Italian language by parents/guardians. Exclusion criteria were readmission within 6 months and parents of a child who died in the PICU. Interventions: Distribution, at PICU discharge, of the EMpowerment of PArents in THe Intensive Care questionnaire with 65 items divided into five domains and a six-point rating scale: 1 “ certainly no” to 6 “certainly yes.” Measurements and Main Results: Back and forward translations of the EMpowerment of PArents in THe Intensive Care questionnaire between Dutch (original version) and Italian languages were deployed. Cultural adaptation of the instrument was confirmed by a consultation with a representative parent group (n = 10). Totally, 150 of 190 parents (79%) participated in the study. On item level, 12 statements scored a mean below 5.0. The Cronbach’s &agr;, measured for internal consistency, on domain level was between 0.67 and 0.96. Congruent validity was measured by correlating the five domains with four gold standard satisfaction measures and showed adequate correlations (rs, 0.41–0.71; p < 0.05). No significant differences occurred in the nondifferential validity testing between three children’s characteristics and the domains; excepting parents with a child for a surgical and planned admission were more satisfied on information and organization issues. Conclusions: The Italian version of the EMpowerment of PArents in THe Intensive Care questionnaire has satisfactory reliability and validity estimates and seems to be appropriate for Italian PICU setting. It is an important instrument providing benchmark data to be used in the process of quality improvement toward the development of a family-centered care philosophy within Italian PICUs.