Non-invasive ventilation for frail elderly patients with acute respiratory failure

We describe 3 elderly patients with acute respiratory failure who received respiratory assistance with nasal bi-level positive airway pressure (BiPAP) on the ward. In these patients with poor prognostic factors, non-invasive positive pressure ventilation was preferred as a reasonable alternative to invasive ventilation; indeed, their admission to the intensive care unit for mechanical support was considered inappropriate. Despite the small number of patients and limited experience with the technique, BiPAP is discussed here as a possible treatment for severe respiratory failure when endotracheal ventilation is controversial, especially in frail patients 80 years of age or older, because invasive ventilation is associated with high mortality and morbidity in these patients. Two questions nevertheless need further evaluation in this setting, and are also addressed. The first is technical: can transient non-invasive breathing assistance be delivered on the ward? The second is ethical: is BiPAP a possible alternative when invasive ventilation is considered inappropriate?     

Non-invasive ventilation in immunocompromised patients with acute hypoxemic respiratory failure

The survival rate of immunocompromised patients has improved over the past decades in light of remarkable progress in diagnostic and therapeutic options. Simultaneously, there has been an increase in the number of immunocompromised patients with life threatening complications requiring intensive care unit (ICU) treatment. ICU admission is necessary in up to 15% of patients with acute leukemia and 20% of bone marrow transplantation recipients, and the main reason for ICU referral in this patient population is acute hypoxemic respiratory failure, which is associated with a high mortality rate, particularly in patients requiring endotracheal intubation. The application of non-invasive ventilation (NIV), and thus the avoidance of endotracheal intubation and invasive mechanical ventilation with its side effects, appears therefore of great importance in this patient population. Early trials supported the benefits of NIV in these settings, and the 2011 Canadian guidelines for the use of NIV in critical care settings suggest the use of NIV in immune-compromised patients with a grade 2B recommendation. However, the very encouraging results from initial seminal trials were not confirmed in subsequent observational and randomized clinical studies, questioning the beneficial effect of NIV in immune-compromised patients. Based on these observations, a French group led by Azoulay decided to assess whether early intermittent respiratory support with NIV had a role in reducing the mortality rate of immune-compromised patients with non-hypercapnic hypoxemic respiratory failure developed in less than 72 h, and hence conducted a multicenter randomized controlled trial (RCT) in experienced ICUs in France. This perspective reviews the findings from their RCT in the context of the current critical care landscape, and in light of recent results from other trials focused on the early management of acute hypoxemic respiratory failure.     

Non-invasive ventilation during arm exercise and ground walking in patients with chronic hypercapnic respiratory failure

Background and objective:   People with chronic hypercapnic respiratory failure (HRF) often have a ventilatory limitation to exercise with difficulty performing activities of daily living. Although non-invasive ventilation (NIV) appears to reduce the ventilatory limitation and improve exercise performance in people with severe COPD, the effect of NIV during functional activities such as unsupported arm exercise (UAE) and ground walking in people with chronic HRF is unclear.
Methods:   Seventeen patients with chronic HRF (PaCO₂ 52.1 ± 5.3 mm Hg) performed a series of UAE tests, and 15 patients (PaCO₂ 51.7 ± 3.8 mm Hg) performed a series of endurance shuttle walk tests, with and without NIV in a randomized cross-over design.
Results:   NIV during UAE increased endurance time by a mean of 91 s (95% confidence interval (CI): 10–172, P  = 0.031) and reduced dyspnoea by a mean of 2.3 on the Borg scale (95% CI: 1.0–3.7, P  = 0.002) compared with exercise without NIV. There was a non-significant increase in walking endurance time with NIV during exercise (119 s, 95% CI: −17 to 254, P  = 0.081); however, isotime dyspnoea was unchanged compared with walking without NIV (−1.0, 95% CI: −3.0 to 1.0, P  = 0.29).
Conclusion:   NIV during UAE increased endurance time and reduced dyspnoea compared with exercise without NIV in patients with chronic HRF. Investigation of the role of NIV as an adjunct to UAE training is warranted. In contrast, NIV during ground walking did not improve exercise capacity. However, the pressure support provided may have been inadequate as dyspnoea was not reduced.     

Noninvasive face mask mechanical ventilation in patients with acute hypercapnic respiratory failure

Mechanically assisted intermittent positive-pressure ventilation effectively provides ventilatory support in patients with respiratory failure but it requires placing an artificial airway. We have previously reported our successful experience delivering mechanical ventilation via a face mask (FMMV) rather than with an endotracheal tube in a pilot study of patients with acute respiratory failure. The present investigation evaluated an additional 18 patients with hypercapnic respiratory failure to determine the efficacy of FMMV in a more homogeneous group and to determine factors predicting its success. FMMV was successful in avoiding intubation in 13 of the 18 patients. A significant initial improvement in PCO2 (greater than 16 percent decrease) and in pH (from less than 7.30 to greater than 7.30) predicted success. The five patients who failed on FMMV required endotracheal intubation because of inability to improve gas exchange (three patients), apnea due to sedatives (one patient), and management of secretions (one patient). FMMV was generally well accepted with only two patients withdrawn because of intolerance of the mask. The mean duration of FMMV was 25 h. Complications were seen in only two patients (11 percent): aspiration (one patient) and mild skin necrosis (one patient). Seven patients entered the study by meeting entrance criteria after an unsuccessful extubation attempt and therefore received both forms of mechanical ventilation. All but one patient avoided reintubation, and the face mask proved to be as effective as the endotracheal tube as a conduit for delivering the mechanical tidal volume and improving gas exchange. Our findings indicate that FMMV is a viable option for short-term (one to four days) ventilatory support of patients with hypercapnic respiratory failure and insufficiency.     

Noninvasive ventilation for acute respiratory failure: a prospective randomised placebo-controlled trial.

The aim of the present study was to clarify whether the known effects of noninvasive positive-pressure ventilation (NPPV) in patients with respiratory failure are real or due to placebo effects and whether early application of NPPV in the emergency department leads to rapid improvement of the patients condition and outcome. A prospective randomised placebo-controlled study was conducted in 20 patients with severe acute respiratory failure (ARF) secondary to an acute exacerbation of chronic obstructive pulmonary disease (COPD) or acute pulmonary oedema, not improving under conventional medical therapy and on the edge of intubation. Patients received either conventional medical therapy plus two-level NPPV (hi-level NPPV) or conventional medical therapy plus "placebo" NPPV. The main outcome measures involved the need for endotracheal intubation in the bi-level NPPV arm and in the placebo arm after crossing over to active NPPV. Morbidity, length of stay, mortality and the effect of the ventilatory mode on clinical, arterial-blood gas parameters, and the sternocleidomastoid muscles electromyogram (EMG) activity were also measured. The 10 patients in the active NPPV group rapidly improved and none needed intubation. Placebo NPPV resulted in no change in the clinical condition of patients that continued to worsen and the 10 patients were crossed over to active NPPV. Three patients were intubated. No differences in terms of morbidity, length of stay or mortality between the two groups were observed. Active NPPV (but not placebo NPPV) led to a rapid and significant improvement in the clinical parameters, pH and the carbon dioxide tension in arterial blood and to a decrease in respiratory frequency and sternocleidomastoid EMG activity. Early application of bi-level noninvasive positive-pressure ventilation in patients with severe acute respiratory failure, due to chronic obstructive pulmonary disease and acute pulmonary oedema, leads to a rapid improvement in clinical status and blood gases. Noninvasive positive-pressure ventilation had no placebo effect.     

Noninvasive vs conventional mechanical ventilation in acute respiratory failure: a multicenter, randomized controlled trial

STUDY OBJECTIVE: Noninvasive mechanical ventilation (NIMV) is beneficial for patients with acute respiratory failure (ARF) when added to medical treatment. However, its role as an alternative to conventional mechanical ventilation (CMV) remains controversial. Our aim was to compare the efficacy and resource consumption of NIMV against CMV in patients with ARF. DESIGN: A randomized, multicenter, controlled trial. SETTING: Seven multipurpose ICUs. PATIENTS: Sixty-four patients with ARF from various causes who fulfilled criteria for mechanical ventilation. INTERVENTION: The noninvasive group received ventilation through a face mask in pressure-support mode plus positive end-expiratory pressure; the conventional group received ventilation through a tracheal tube. MEASUREMENTS AND RESULTS: Avoidance of intubation, mortality, and consumption of resources were the outcome variables. Thirty-one patients were assigned to the noninvasive group, and 33 were assigned to the conventional group. In the noninvasive group, 58% patients were intubated, vs 100% in the conventional group (relative risk reduction, 43%; p < 0.001). Stratification by type of ARF gave similar results. In the ICU, death occurred in 23% and 39% (p = 0.09) and complications occurred in 52% and 70% (p = 0.07) in the noninvasive and conventional groups, respectively. There were no differences in length of stay. The Therapeutic Intervention Score System-28, but not the direct nursing activity time, was lower in the noninvasive group during the first 3 days. CONCLUSIONS: NIMV reduces the need for intubation and therapeutic intervention in patients with ARF from different causes. There is a nonsignificant trend of reduction in ICUs and hospital mortality together with fewer complications during ICU stay.     

Determinants of prolonged mechanical ventilation in patients with chronic obstructive pulmonary diseases and acute hypercapnic respiratory failure

BACKGROUND: The aim of the present study was to identify early risk factors for prolonged mechanical ventilation (PMV) in chronic obstructive pulmonary disease (COPD) patients admitted to respiratory intensive care units (RICU) for acute hypercapnic respiratory failure. METHODS: PMV was defined as invasive ventilation lasting longer than 7 days. Between January 1, 2000 and December 31, 2005, epidemiological and clinical data on RICU admission day were retrospectively analyzed for eligible patients. Univariate and multiple stepwise logistic regression analyses were used for statistical analysis. RESULTS: A total of 152 patients were eligible for evaluation during the 6-year study period and their mean age was 63+/-12 years. Fifty-one patients died before day 7 after the onset of MV (early death group). Of the remaining 101 patients who survived until day 7, 56 had been weaned successfully (non-PMV group) and 45 continued to receive MV (PMV group). Logistic regression analysis showed that age above 65 (OR=1.98, 95% CI=0.96-4.17, P=0.011), a pH of 7.30 or less measured 12 h after ventilation (OR=2.09, 95% CI=1.17-5.64, P=0.002), an APACHE II score above 20 (OR=3.25, 95% CI=1.58-7.10, P<0.001), development of non-respiratory organ failure (OR=4.67, 95% CI=1.54-9.71, P<0.001), and the presence of shock (OR=4.71, 95% CI=2.14-10.09, P<0.001) were independently associated with PMV. The presence of two factors predicted PMV with a sensitivity of 86% and a specificity of 94%. CONCLUSION: Age, APACHE II score, refractory acidosis, presence of non-respiratory organ failure, and shock on RICU admission day were early determinants of PMV in patients with COPD and acute hypercapnic respiratory failure.     

Non-invasive ventilation in the management of acute respiratory failure in Pakistan

Data were collected from hospital records on all patients who received non-invasive ventilation (NIV) during the period 1999-2000. Patients were treated with NIV if they had type I or type II respiratory failure or if they had respiratory distress with a respiratory rate above 30/min. A total of 68 patients (35 males) were studied. NIV was applied using a Respironics Bi-PAP device mostly on a high-dependency unit (HDU). A successful outcome with NIV was achieved in 70% (26/37) of patients with type II failure, 65% (11/17) patients with type I failure and 64% (9/14) patients with respiratory distress. Of the 16 patients considered to be inappropriate for invasive ventilation on admission, eight were treated successfully with NIV. NIV can be applied successfully in developing countries.     

Non-invasive ventilation in acute respiratory insufficiency

Non invasive mechanical ventilation represents all the techniques of mechanical ventilation not using endotracheal connection to the respirator. Non invasive mechanical ventilation is essentially represented nowadays by facial (generally used for acute respiratory failure) and nasal ventilation (widely used for long term mechanical ventilation at home). Following in France the first studies of Rideau in the '80 in patients with chronic respiratory failure secondary to muscular dystrophy, Meduri, then Brochard demonstrated the interest of non invasive mechanical ventilation in the management of acute on chronic respiratory failure. A simple algorithm is thus able to recommend in first attempt use of non invasive mechanical ventilation in acute on chronic respiratory failure except if the patient presents in a severe respiratory status imposing in first line endotracheal ventilation. In parallel, more recent studies have demonstrated the interest of that technique in immediate ventilatory link in the spectrum of weaning of endotracheal mechanical ventilation. In hypoxic acute respiratory failure, non invasive mechanical ventilation remains controversial and seems to be better indicated in moderate to severe respiratory status.     

Non-invasive pressure support ventilation in patients with respiratory failure due to severe acute cardiogenic pulmonary edema

BACKGROUND: Recent studies suggest the use of non-invasive pressure support ventilation (NIPSV) in patients with acute cardiogenic pulmonary edema (ACPE). However, it remains unclear whether all patients with ACPE benefit from NIPSV. OBJECTIVES: To investigate short-term effects of NIPSV on respiratory, hemodynamic and oxygenation parameters in patients with respiratory failure due to severe ACPE and to identify factors predicting the need for intubation and in-hospital mortality. METHODS: In a prospective, uncontrolled, open study, 28 patients admitted with signs and symptoms of severe respiratory distress due to ACPE were given NIPSV in addition to standardized pharmacological treatment. Physiological parameters were obtained before and after NIPSV, and intubation rate and in-hospital mortality were recorded. RESULTS: NIPSV increased arterial oxygenation from paO2 54.2 +/- 12.4 to 76.9 +/- 12.6 mm Hg (p = 0.0001) and decreased respiratory frequency from 40.1 +/- 8.2 to 22.4 +/- 4.9 breaths/min (p = 0.0001). Significant improvements were also noted for heart rate, blood pressure and the paO2/FiO2 ratio. Four patients (14%) required intubation despite NIPSV. Patients who required intubation had lower paCO2 levels (p = 0.0002), lower serum bicarbonate concentrations (p = 0.04) and lower systolic blood pressure (p = 0.045) than patients who were successfully treated with NIPSV. Eight patients (28.5%) died during hospitalization. In patients with a paCO2 < or =35 mm Hg on admission, the in-hospital mortality was 87%, but in patients with a paCO2 >35 mm Hg the in-hospital mortality was 6%. CONCLUSIONS: NIPSV improves oxygenation and alleviates respiratory distress in patients with respiratory failure due to severe ACPE. However, a subgroup of patients with hypocapnia on admission might have a poor prognosis, with a higher risk of intubation and in-hospital mortality.