Noninvasive ventilation

Endotracheal intubation and mechanical ventilation have traditionally been employed in patients with acute respiratory insufficiency. However, this form of management can have serious adverse effects, mainly infections and barotrauma. Noninvasive ventilation (NIV) has been shown to be an effective alternative, as it reduces both the frequency of complications and cost of care. In fact, NIV is currently the first choice treatment for acute respiratory insufficiency in patients who have chronic obstructive pulmonary disease or who are immunocompromised. It is also commonly applied in patients with asthma, pneumonia, and acute cardiogenic pulmonary edema. Correct indication and training in use of NIV equipment is necessary to ensure success and facilitate patient tolerance.     

Noninvasive pressure support ventilation

In appropriately selected patients, NPPV decreases intubation rate, improves survival, and is cost-effective. Pressure support ventilation is commonly used successfully for NPPV. An issue with the use of pressure support is the ability of the ventilator to detect the end of inhalation in the presence of leaks or in patients with severe airflow obstruction. A concern with portable pressure ventilators is the potential for rebreathing of carbon dioxide. Despite these issues, pressure support ventilation has been used successfully for noninvasive ventilation in thousands of patients with acute respiratory failure.     

Noninvasive ventilation in adult liver transplantation

Noninvasive ventilation (NIV) has proven to be a safe and effective technique in the treatment of respiratory failure complicating various medical and surgical diseases. In recent years, a growing interest has emerged in its adoption for ventilatory assistance in immunocompromised patients, such as those undergoing bone marrow, liver, lung, cardiac, and kidney transplantation. Weaning from the ventilator after liver transplantation can take longer because of unsatisfactory gas exchange during various attempts of T-piece trials. Rapid extubation followed by an immediate NIV application should be considered in this setting to shorten and accelerate the weaning process in those recipients who do not completely fulfill the criteria for safe extubation. By adding the pressure support (PS) mode with a continuous positive end expiratory pressure (PEEP), NIV could prevent the loss of vital capacity and impede severe lung derecruitment following extubation. Clinical experience has shown that properly delivered NIV mostly benefits moderately dyspneic recipients in acute respiratory failure, while it appears less promising and efficient in patients ventilated for extended periods of time. It has proven safe and efficient mainly as (1) a tool to promote an early ventilatory discontinuation and extubation; (2) a prophylactic strategy for preventing postoperative pulmonary complications; and (3) a simple method to start with in cases of acute hypoxic and/or hypercapnic respiratory failure. The improvements in arterial hypoxemia, the decreased ventilatory demand provided with an inspiratory support, as well as the scarcity of hemodynamic repercussions are among the major benefits of this method.     

Noninvasive ventilation options in pediatric myasthenia gravis

A 10-month-old female infant with congenital myasthenic syndrome suffering from acute respiratory failure was supported using face mask positive pressure ventilation until definitive diagnosis and specific treatment was achieved. A 12-year-old girl suffering from seronegative myasthenia gravis was treated by helmet-delivered noninvasive ventilation during recurrent myasthenic episodes. Noninvasive support was really beneficial in the myasthenic crisis with respiratory muscle weakness, whereas a shift to tracheal intubation was necessary when pulmonary infection and multiple atelectasis occurred. The new helmet interface for noninvasive positive pressure ventilation can represent a valuable means of respiratory support in the early phase of respiratory failure in older children.     

Noninvasive ventilation for decompensation of chronic respiratory failure

MASK DELIVERY: Noninvasive ventilation designates ventilation methods which do not use the endotracheal route. Noninvasive ventilation is generally delivered via a facial mask (generally for patients with acute respiratory failure) or a nasal mask (widely used for home-delivery systems). INDICATIONS: Following work conducted by Rideau in the eighties who made the first ventilation trials in patients with myopathy, Meduri then Brochard focused interest on noninvasive ventilation for the management of acute episodes in patients with chronic respiratory failure. Following a simple algorithm, first intention noninvasive ventilation can be used in case of acute decompensation of chronic respiratory failure when the degree of urgency and the patient's status do not require immediate endotracheal ventilation. A WEANING TOOL: In addition to this well recognized indication, recent trials have demonstrated the usefulness of noninvasive ventilation as a weaning tool for patients on conventional endotracheal ventilation.     

Noninvasive ventilation in a child affected by achondroplasia respiratory difficulty syndrome

Achondroplasia can result in respiratory difficulty in early infancy, from anatomical abnormalities such as mid-facial hypoplasia and/or adenotonsillar hypertrophy, leading to obstructive apnea, or to pathophysiological changes occurring in nasopharyngeal or glossal muscle tone, related to neurological abnormalities (foramen magnum and/or hypoglossal canal problems, hydrocephalus), leading to central apnea. More often, the two respiratory components (central and obstructive) are both evident in mixed apnea. Polysomnographic recording should be used during preoperative and postoperative assessment of achondroplastic children and in the subsequent follow-up to assess the adequacy of continuing home respiratory support, including supplemental oxygen, bilevel positive airway pressure, or assisted ventilation.     

Noninvasive high-frequency percussive ventilation in the prone position after lung transplantation

Noninvasive positive-pressure ventilation (NIV), which represents a consolidated treatment of both acute and chronic respiratory failure, is increasingly being used to maintain spontaneous ventilation in lung transplant patients with impending pulmonary complications. Adding a noninvasive inspiratory support plus positive end-expiratory pressure (PEEP) has proven to be useful in preventing endotracheal mechanical ventilation, airway injury, and infections. Lung recipients with closure of the small airways in the dependent regions may also benefit from the prone position, which is helpful to promote recruitment of nonaerated alveoli and faster healing of consolidated atelectatic areas. In patients with localized or diffuse lung infiltrates, high-frequency percussive ventilation (HFPV), by either an invasive airway or a facial mask, has been adopted as an alternative ventilatory mode to enhance airway opening, limit potential respirator-associated lung injury, and improve mucus clearance. In nonintubated lung recipients at risk for volubarotrauma with conventional mechanical ventilation, it allows oxygen diffusion into the distal airways at lower mean airway pressures while avoiding repetitive cyclical opening and closing of the terminal airways. We summarize the clinical course of 3 patients with post-lung transplantation respiratory complications who were noninvasively ventilated with HFPV in the prone position. Major advantages of this treatment included gradual improvement of spontaneous clearance of bronchial secretions, significant attenuation of graft infiltrates and consolidations, a reduction in the number of bronchoscopies required, a decrease in spontaneous respiratory rate and work of breathing, and a significant improvement in gas exchange. The patients found HFPV with either standard facial mask or total mask interface to be comfortable or only mildly uncomfortable, and after the sessions they felt more restored. HFPV by facial mask in the prone position may be an interesting and attractive alternative to standard NIV, one that is more useful when implemented before full-blown respiratory failure is established.     

Noninvasive positive pressure ventilation in patients with perioperative negative pressure pulmonary edema

Negative pressure pulmonary edema (NPPE) is a noncardiogenic pathological process that is treated with invasive ventilation via a tracheal tube. To investigate the feasibility and safety of noninvasive positive pressure ventilation (NPPV) as an alternative treatment for NPPE, we retrospectively reviewed charts of 15 perioperative NPPE patients. Eight patients were treated by NPPV and 7 were treated by invasive ventilation. Patient characteristics, duration of NPPV, duration of intensive care unit (ICU) stay, and maximum airway pressure were investigated for the NPPV-treated patients. All patients treated by NPPV had a patent airway after complete relief of the airway obstruction and recovered from NPPE symptoms within one postoperative day. Arterial blood gas analysis showed a significant improvement in the PaO₂/FiO₂ ratio from 132 ± 30 mmHg in the operating room to 282 ± 77 mmHg at discontinuation of NPPV. Serious complications, such as ventilator-associated pneumonia or aspiration pneumonia, did not occur, and intubation was not required for any patient. Favorable outcomes in these cases suggest that NPPV could be a feasible and safe alternative for treating NPPE if the patency of the airway is restored.     

Noninvasive carbon dioxide monitoring during one-lung ventilation: end-tidal versus transcutaneous techniques

OBJECTIVE: To compare transcutaneous CO(2) (TCCO(2)) and end-tidal CO(2) (ETCO(2)) monitoring during one-lung ventilation (OLV). DESIGN: Prospective study. SETTING: Operating room of a University Hospital. PARTICIPANTS: Fifteen patients undergoing thoracic surgical procedures in whom one-lung ventilation was deemed necessary. INTERVENTION: TC and ETCO(2) monitors were used simultaneously in the patients and compared with arterial blood gases (ABGs) during 2-lung ventilation and OLV.MEASUREMENTS AND MAIN RESULTS: During 2-lung ventilation (TLV), the ET to PaCO(2) difference was 3.9 +/- 1.6 mmHg, whereas the TC to PaCO(2) difference was 2.5 +/- 0.8 mmHg (p = 0.0049). During OLV, the ET to PaCO(2) difference increased to 5.8 +/- 2.3 mmHg, whereas the TC to PaCO(2) difference was 2.7 +/- 1.4 mmHg (p = 0.0049 for ET to PaCO(2) difference during OLV v TLV and p = 0.0004 for ET to PaCO(2) gradient v TC to PaCO(2) gradient during OLV). During TLV, the difference between the ET and PaCO(2) was < or = 5 mmHg in 13 of 15 patients, whereas the difference between the TC and PaCO(2) was < or = 5 mmHg in 15 of 15 patients (p = not significant). During OLV, the difference between the ET and the PaCO(2) was < or = 5 mmHg in 6 of 15 patients, whereas the difference between the TC and PaCO(2) was < or = 5 mmHg in 14 of 15 patients (p = 0.0052, odds ratio 21.0 for ET v TC techniques and p = 0.02, odds ratio 9.75 for ET to PaCO(2) during TLV v OLV). CONCLUSIONS: During OLV, TCCO(2) monitoring provides a more accurate estimate of PaCO(2) than ET techniques.     

Noninvasive ventilation for pediatric patients including those under 1-year-old undergoing liver transplantation.

Pulmonary complications are an important cause of the mortality associated with liver transplantation. The efficacy of noninvasive ventilation (NIV) in pediatric patients following transplantation is unknown. The purpose of this retrospective study is to investigate the effects of NIV for pediatric patients undergoing liver transplantation. Of 102 pediatric patients who underwent liver transplantation, 15 patients (aged 73 months; range 2.5-179) were supported by NIV because of atelectasis, hypercapnia, hypoxemia, pneumonia, massive effusion, or postextubation ventilatory support. Of 15 patients, 5 were under the age of 1 year (range 2.5-12 months). Of the 15 patients, 7 had required multiple intubations before NIV treatment because of pulmonary complications. NIV treatment was administered to 6 patients because of hypercapnia. Partial pressure of arterial carbon dioxide (PaCO(2)) levels improved from 56.9 (95% confidence interval [CI]: 48.4-65.4) to 41.5 (95% CI: 36.8-46.2) mmHg (P = .028) within 2 days. NIV treatment was very effective for patients with atelectasis with and without other pulmonary complications. Mean inspiratory positive pressure (IPAP) was 7.2 (95% CI: 6.0-8.3) cm H(2)O and expiratory positive pressure (EPAP) was 3.5 (95% CI: 3.2-3.9) cm of H(2)O. Mean duration of NIV was 18.5 (95% CI: 8.6-28.4) days. IPAP and EPAP levels were closely and significantly correlated with height (IPAP: r = .65, P = .016; EPAP: r = .77, P = .004). A total of 13 patients recovered and 2 patients died. However, no patient died of respiratory complications. In conclusion, NIV is effective in pediatric patients undergoing liver transplantation with subsequent pulmonary complications. The IPAP and EPAP levels may be predicted by the height of the patient.     

Noninvasive proportional assist ventilation may be useful in weaning patients who failed spontaneous breathing trial

BackgroundEndotracheal mechanical ventilation (ETMV) is accompanied with a high morbidity and mortality in intensive care unit (ICU) patients. The aim of this prospective randomized controlled study was to evaluate the effectiveness of noninvasive proportional assist ventilation (PAV) as a method of weaning in patients who could not tolerate spontaneous breathing trial (SBT).Patients and methodsAmong 112 patients presented with acute respiratory failure (ARF) admitted to Zagazig university surgical ICU, 42 patients of them failed a 2 h-SBT after they met simple criteria for weaning. Conventional invasive synchronized intermittent mandatory ventilation (SIMV) was used as the control weaning technique in 21 patients (SIMV group), and noninvasive PAV was applied immediately after extubation in the remaining 21 patients (PAV group).ResultsThere was no significant difference regarding the main clinical, functional characteristics, and the physiologic parameters of the two weaning groups at the time of their admission. Gas exchange at 1-h post-randomisation was significantly improved in both groups. The duration of ventilatory support was significantly shorter in the PAV group (12.8 + 8.3 days vs 22.3 + 13.3 days in the conventional group; P < 0.05). Weaning success was significantly higher in the PAV group (18 patients“85%” vs 11 patients “52 %” in the conventional group P < 0.05). ICU survival was higher, while, reintubation rate was lower in PAV (three patients “14%” vs 10 patients “47%” in the conventional group; P < 0.05). The rate of tracheostomy was significantly lower in the PAV group (one patient “4%” vs seven patients “33%” in the conventional group; P < 0.05). The incidence of VAP was higher in the conventional group (eight patients “38%” vs one patient “4%”in the PAV group; P < 0.05).ConclusionNoninvasive PAV could be considered as an effective and safe method of weaning in patients who cannot tolerate 2 h-SBT.