Positive Pressure Ventilation

edema [5] in adults, there are few reports about its use in this acute setting in children. So far, case series con- stitute the vast majority of the available knowledge in this age group. However, there is an increasing interest in the use of NPPV as a therapeutic tool for children with respiratory distress that is clear from the increasing number of published studies over time (Figure 1); a research of studies on the use of NPPV in children > 1 month of age, published before December 30, 2010 (database: MEDLINE via PubMed; keywords: noninva- sive ventilation, non-invasive ventilation, noninvasive positive pressure ventilation, non-invasive positive pres- sure ventilation, bipap, continuous positive airway pres- sure; age limits: children from 1 month to 18 years old) identified 332 relevant articles, of which 48% were pub- lished during the past 5 years. This concise review is designed to focus on the effectiveness of NPPV in chil- dren > 1 month of age with ARF (excluding patients with neurologic or chronic lung disease).

The first (baseline) transthoracic echocardiography (TTE) was performed after the arrival in the preopera- tive area within 60 min before induction of anesthesia, with the patient awake, un-premedicated and in a partial left lateral position. Ten to fifteen minutes after induc- tion of anaesthesia, intubation and start of intermittent positive pressure ventilation (IPPV), the second echocar- diographic examination was performed also in a partial left lateral position by the same investigator. General an- aesthesia was induced and maintained by infusion of propofol and remifentanil. Rocuronium 0.6 mg kg − 1 was administered before the tracheal intubation. PPV to nor- mocapnia (end-tidal carbon dioxide 4.5–5 kPa) was com- menced with ventilator settings at the discretion of the attending anaesthesiologist. Hypotension, defined as a

External negative-pressure ventilation with tank respirators is very successful in treating patients with chronic obstructive pulmonary disease [6], but there are no data regarding patients with hypoxaemic acute respiratory failure. Recent experimental data suggest that continuous external negative-pressure ventilation (CENPV) may distend lungs in a fundamentally differ- ent manner from CPPV and may result in better oxy- genation and less lung injury at lower transpulmonary pressures [7]. Extrapolation to patients is difficult, and to date only continuous external negative-pressure (CENP) has been applied in three ARDS patients who breathed spontaneously in Emerson tank respirators [8-10]. Furthermore, cuirass [11] or poncho wrap sys- tems [12,13] have been used for CENP during inter- mittent positive-pressure ventilation (IPPV), which resulted in improved cardiac output [11-13]. However, both cuirass and poncho wrap systems decrease chest wall compliance when they are affixed to the body [11-13], and effective ventilation in patients with ARDS has not been reported with either these systems or with tank respirators.

clear distinction in the Neonatal Re- suscitation Program (NRP) guidelines between those who receive short period of positive pressure ventilation (PPV) at birth and those who require prolonged and more extensive resuscitation in terms of the postresuscitation care (PRC) needed. The nature and duration of this PRC may vary signi fi cantly after different degrees of perinatal depres- sion. Although some of these infants can be at high risk for further deterioration, others may be able to receive routine neonatal care. 4,6 Indiscriminate inclu-

the participants. The SIB delivered the lowest number of effective breaths (73.9%). The T-piece resuscitator de- livered the maximum number of effective ventilations (88.9%). This difference was observed as T-piece and AB can be utilized only if the seal is adequate. Finer et al. compared different groups based on level of training for the three devices and detected a difference among groups for the various devices [8]. Other studies do not detect a difference among the groups for any of the de- vices [6,7,13]. In the present study, no correlation was found between qualification of the operator and pres- sures achieved except PEEP while providing manual positive pressure ventilation, but breath-rate per minute and effective breath-rate varied with qualification. This is probably due to the fact that consultants, and residents routinely performed neonatal resuscitation, and thereby were able to perform better than nurses. Twenty-nine (72.5%) of the participants, preferred the T-piece resusci- tator, while four participants preferred the AB and seven participants preferred the SIB.

Noninvasive positive pressure ventilation (NPPV) refers to the delivery of mechanical ventilation to the lungs using techniques that do not require an endotracheal intubation. In the past decade NPPV has gained wide acceptance and is now used more frequently after development of portable ventilators, new modes of ventilation and other equipments. This article will provide a comprehensive overview of the current stage of NPPV in acute and chronic settings. It will appraise the evidence based efficacy of NPPV in patients who presented with acute exacerbation of chronic hypercapneic respiratory failure. The main focus of discussion in this article is to provide detailed knowledge regarding choosing appropriate ventilators and interfaces, selecting appropriate patients and initiating NPPV and their weaning.

Case presentation: We describe the case of a patient with Chronic Obstructive Pulmonary Disease (COPD), from whom we recorded EAdi during four different ventilatory conditions: 1) invasive mechanical ventilation, 2) spontaneous breathing trial (SBT), 3) unassisted spontaneous breathing, and 4) Noninvasive Positive Pressure Ventilation (NPPV). The patient had been intubated due to an exacerbation of COPD, and after four days of mechanical ventilation, she passed the SBT and was extubated. Clinical signs of respiratory distress were present immediately after extubation, and EAdi increased compared to values obtained during mechanical ventilation. As we started NPPV, EAdi decreased substantially, indicating muscle unloading promoted by NPPV, and we used the EAdi signal to monitor respiratory effort during NPPV. Over the next three days, she was on NPPV for most of the time, with short periods of spontaneous breathing. EAdi remained considerably lower during NPPV than during spontaneous breathing, until the third day, when the difference was no longer clinically significant. She was then weaned from NPPV and discharged from the ICU a few days later.

dyspnea, and impaired quality of life. Nocturnal noninvasive positive pressure ventila- tion (NPPV) can theoretically rest overloaded respiratory muscles, prevent nocturnal hypoventilation, and reset central respiratory drive in patients with hypercapnia. The use of NPPV in late-stage COPD appears logical to change this inexorable course, to alleviate symptoms, and to improve quality of life. While NPPV has a definite role in the management of acute hypercapnic respiratory failure, 4 its role in the management

When the analysis was performed in the 3 predesignated BW categories, the overall rates of BPD and BPD/death were significantly lower in the 500- to 750-g BW category for infants treated with SNIPPV (Table 3). Logistic regres- sion analyses adjusting for center, BW, GA, small for GA, race, gender, antena- tal steroids, Apgar scores at 1 and 5 minutes, RDS, surfactant use, postna- tal steroids, late-onset sepsis, PDA, se- vere IVH, PVL, birth year, and duration of CPAP and/or mechanical ventilation showed that infants treated with SNIPPV in the 500- to 750-g BW weight category were significantly less likely to develop BPD (odds ratio [OR]: 0.29 [95% confidence interval (CI): 0.11–0.76]; P ⫽ .01) or BPD/ death (OR: 0.30 [95% CI: 0.11– 0.79]; P ⫽ .01), overall (Table 4). There were no significant differences be- tween the SNIPPV and no-SNIPPV groups in BPD or BPD/death noted in the other BW categories.

more commonly studied ventilated COPD obstructed patients could be applied to obstructed asthmatic patients as well. A common problem with NPPV is leaks from the mask that may impair the expiratory trigger or flow cycling when inspiratory pressure support ventilation is used. In the presence of air leaks, modern ventilators do not decrease inspiratory flow due to leak compensation. As there is no decrease in flow, the ventilator will not cycle to expiration. This leads to prolonged inspiratory time and patient–ventilator asynchrony. An alternative way to flow cycling is time cycling. Limiting inspiratory time independent of air leaks allows a shorter inspiratory time. We usually set the inspiratory time to 1 to 1.3 s. However, this should be adjusted on an individual basis, and at times shorter inspiratory times are needed in severely obstructed patients. Modern ventilators allow adjust- able flow cycling that, in case of leak, can also be time limited. This is probably the ideal way for expiratory trigger in noninvasive ventilation.

Chronic heart failure (CHF) has been shown to be associated with an increased incidence of sleep-disordered breathing. Whether treatment with noninvasive positive- pressure ventilation (NPPV), including continuous positive airway pressure, bi-level positive airway pressure and adaptive servo-ventilation, improves clinical outcomes of CHF patients is still debated. 2,832 CHF patients were enrolled in our analysis. NPPV was significantly associated with improvement in left ventricular ejection fraction (39.39% vs. 34.24%; WMD, 5.06; 95% CI, 3.30-6.81; P < 0.00001) and plasma brain natriuretic peptide level (268.23 pg/ml vs. 455.55 pg/ml; WMD, -105.66; 95% CI, [-169.19]-[-42.13]; P = 0.001). However, NPPV did not reduce all-cause mortality (0.26% vs. 0.24%; OR, 1.13; 95% CI, 0.93-1.37; P = 0.22) or re-hospitalization rate (57.86% vs. 59.38%; OR, 0.47; 95% CI, 0.19-1.19; P = 0.02) as compared with conventional therapy. Despite no benefits on hard endpoints, NPPV may improve cardiac function of CHF patients. These data highlight the important role of NPPV in the therapy of CHF.

Results: A 100% response rate was obtained. In the Delivery Room, sustained lung inflation was performed in 74. 8% of centres, and 89.2% used NCPAP. For ELGANs who need invasive MV, conventional MV was the most used strategy. Volume-targeted ventilation and High-frequency oscillatory ventilation (HFOV) were considered as primary mode in < 30% of centres. Among non-invasive strategies, NCPAP was the most utilized, followed by BiPAP, High- flow nasal cannula and nasal intermittent positive pressure ventilation. Nurses more commonly recorded in the nursing charts the ventilator ’ s setting parameters rather than measured ones. HFOV and non-invasive ventilation were the most quoted aspects of neonatal ventilation felt as to be improved.

In neonatal acute respiratory distress syndrome (ARDS)- like lung disorders different therapeutic approaches have been introduced in the last years. These include mechani- cal ventilation strategies as well as exogenous surfactant administration. Various animal studies have focussed this topic and different regimes have been introduced into clinical practice although large clinical trials have not been performed yet [1-3]. As shown in experimental stud- ies, the open lung concept (OLC) as an alternative venti- lation strategy, improves gas exchange and reduces ventilator-induced lung injury in models of secondary surfactant deficiency [4,5]. These effects were seen while applying the OLC during high-frequency oscillatory venti- lation an positive pressure ventilation [4]. Furthermore, histology and biochemical analyses of bronchoalveolar lavage specimen showed reduced signs of lung injury and pulmonary inflammation in OLC ventilated animals [5]. However, respiratory failure in term neonates is often accompanied by secondary surfactant deficiency, contrib- uting to impairment of lung function in these infants. Thus, exogenous surfactant administration in neonatal ARDS-like lung injury is a clinically well established treat- ment option [1,6,7]. Even in meconium aspiration syn- drome, leading to severe inflammatory-induced lung failure, exogenous surfactant administration is part of therapeutic concepts [8]. Experimentally, the restoration of pulmonary function and gas exchange as well as the amelioration of pulmonary inflammatory processes has been shown [9]. Nevertheless, it has not been extensively investigated whether surfactant therapy in neonatal ARDS attains different effects on gas exchange, lung function, surfactant homoeostasis or pulmonary inflammatory processes compared to the OLC without surfactant replacement, although these effects may lead to differ- ences in short and long term pulmonary outcome follow- ing neonatal ARDS. Furthermore, there is still no consensus on ventilation strategy in these infants in com- bination or without surfactant administration until now [10].

(CPAP) or noninvasive positive pressure ventilation (NPPV), for the management of patients with blunt chest trauma has not been established [5,6]. Although the safety of both CPAP and NPPV has been assessed in a number of observational studies in patients with blunt thoracic injuries [7-10], the evidence regarding the use of NIV in this setting is inconsistent [6]. Data derived from large multicenter trials evaluating NIV use in hypoxemic patients is not generalizable to these patients, as these trials included few trauma patients [11]. Two recent guidelines have offered a “ no recommendation ” or a “low-grade recommendation” for the use of NIV in blunt chest trauma [12,13]. However, these guidelines do not include the totality of the available data for this clinical condition.

Several theoretical concerns have been proposed with NIV in addition to the inherent risk of barotrauma from all types of positive pressure ventilation. With elevated intrathoracic pressure, increased resistance to ven- tricular ejection occurs. This is probably of little con- sequence in the normal heart, but in a failing myocardium, an increased workload can decrease car- diac output. For example, in atrial fibrillation treated with CPAP, a decline in left ventricular ejection fraction (LVEF), especially in the setting of low systemic vascular resistance (SVR), occurs. 14 This suggests that the hemo- dynamic impact of NIV in ADHF may be significant. Table 4

Noninvasive positive pressure ventilation (NPPV) ther- apy has been reported to improve not only dyspnea and respiratory distress caused by cardiogenic pulmonary edema but also cardiovascular hemodynamics [1]. Namely, NPPV therapy is beneficial for both the respiratory and hemodynamic functions of patients with heart failure. In Japan, NPPV therapy is recommended for patients with acute heart failure who do not respond to oxygen therapy as a therapy categorized to class I in treatment recommen- dation and to A in evidence level [2]. These facts lead us to conjecture that NPPV therapy is potentially effective for patients presenting with symptoms that are attributable to the insufficient long-term management of pulmonary con- gestion/edema (for example, dyspnea at rest, intense fatig- ability, orthopnea, and paroxysmal nocturnal dyspnea). Nevertheless, NPPV therapy has not become established as a therapeutic modality for CHF because conventional medical devices for NPPV therapy are difficult to use for a long period due to their problems (for example, cumbersome operability of the devices and poor patient adherence).

Figure 4 Tidal hyperaeration during pressure support ventilation (PSV), biphasic positive pressure ventilation + spontaneous breaths (BI- PAP+SB mean ), controlled (BIPAP+SB controlled ) and spontaneous (BIPAP+SB spont ) breath cycles. Calculations were performed for different lung zones from ventral to dorsal (1 = ventral, 2 = mid-ventral, 3 = mid-dorsal, and 4 = dorsal) at lungs apex, hilum, and base using dynamic computed tomography. The contributions of BIPAP+SB spont and BIPAP+SB controlled to BIPAP+SB mean were weighted by their respective rates (weighted mean). Bars and vertical lines represent means and standard deviations, respectively. * P < 0.05 vs. PSV; † P < 0.05 vs. BIPAP+SB controlled .

In victims of submersion who have been apneic, positive pressure ventilation.. of the lungs should not be discontinued.[r]

The degree of lung damage in VILI can be linked to the amount of energy transferred from the mechanical ventilator to the respiratory system within a given timeframe, a construct known as mechanical power. There are several ways of calculating mechanical power, from simple formulas to highly complex equations. All have distinct benefits and shortcomings; some compute static mechanical energy and resistive pressure, while others disregard these parameters. Regardless of the way in which mechanical power is calculated, it is worth stres- sing that not all alveolar units will be exposed to it. Therefore, efforts should focus on nor- malizing mechanical power to the lung surface area amenable to ventilation. The recognition that mechanical power may reflect a conjunction of parameters which can pre- dispose to VILI is an important step toward better care of critically ill patients.

Methods: Multi-center open label randomized controlled trial of 150 patients having survived an admission with noninvasive ventilatory treatment of acute hypercapnic respiratory failure due chronic obstructive pulmonary disease. The included patients are randomized to usual care or to continuing the acute noninvasive ventilation as a long-term therapy, both with a one-year follow-up period. The primary endpoint is time to death or repeat acute hypercapnic respiratory failure; secondary endpoints are one-year mortality, number of readmissions and repeat acute hypercapnic respiratory failure, exacerbations, dyspnea, quality of life, sleep quality, lung function, and arterial gases. Discussion: Though previous studies of long-term noninvasive ventilation have shown conflicting results, we believe the treatment can reduce mortality and readmissions when applied in patients with previous need of acute ventilatory support, regardless of persistent hypercapnia.