Noninvasive ventilation for severely acidotic patients in respiratory intermediate care units : Precision medicine in intermediate care units.

BACKGROUND: Severe acidosis can cause noninvasive ventilation (NIV) failure in chronic obstructive pulmonary disease (COPD) patients with acute hypercapnic respiratory failure (AHRF). NIV is therefore contraindicated outside of intensive care units (ICUs) in these patients. Less is known about NIV failure in patients with acute cardiogenic pulmonary edema (ACPE) and obesity hypoventilation syndrome (OHS). Therefore, the objective of the present study was to compare NIV failure rates between patients with severe and non-severe acidosis admitted to a respiratory intermediate care unit (RICU) with AHRF resulting from ACPE, COPD or OHS. METHODS: We prospectively included acidotic patients admitted to seven RICUs, where they were provided NIV as an initial ventilatory support measure. The clinical characteristics, pH evolutions, hospitalization or RICU stay durations and NIV failure rates were compared between patients with a pH ≥ 7.25 and a pH < 7.25. Logistic regression analysis was performed to determine the independent risk factors contributing to NIV failure. RESULTS: We included 969 patients (240 with ACPE, 540 with COPD and 189 with OHS). The baseline rates of severe acidosis were similar among the groups (45 % in the ACPE group, 41 % in the COPD group, and 38 % in the OHS group). Most of the patients with severe acidosis had increased disease severity compared with those with non-severe acidosis: the APACHE II scores were 21 ± 7.2 and 19 ± 5.8 for the ACPE patients (p < 0.05), 20 ± 5.7 and 19 ± 5.1 for the COPD patients (p < 0.01) and 18 ± 5.9 and 17 ± 4.7 for the OHS patients, respectively (NS). The patients with severe acidosis also exhibited worse arterial blood gas parameters: the PaCO2 levels were 87 ± 22 and 70 ± 15 in the ACPE patients (p < 0.001), 87 ± 21 and 76 ± 14 in the COPD patients, and 83 ± 17 and 74 ± 14 in the OHS patients (NS)., respectively Further, the patients with severe acidosis required a longer duration to achieve pH normalization than those with non-severe acidosis (patients with a normalized pH after the first hour: ACPE, 8 % vs. 43 %, p < 0.001; COPD, 11 % vs. 43 %, p < 0.001; and OHS, 13 % vs. 51 %, p < 0.001), and they had longer RICU stays, particularly those in the COPD group (ACPE, 4 ± 3.1 vs. 3.6 ± 2.5, NS; COPD, 5.1 ± 3 vs. 3.6 ± 2.1, p < 0.001; and OHS, 4.3 ± 2.6 vs. 3.7 ± 3.2, NS). The NIV failure rates were similar between the patients with severe and non-severe acidosis in the three disease groups (ACPE, 16 % vs. 12 %; COPD, 7 % vs. 7 %; and OHS, 11 % vs. 4 %). No common predictive factor for NIV failure was identified among the groups. CONCLUSIONS: ACPE, COPD and OHS patients with AHRF and severe acidosis (pH ≤ 7.25) who are admitted to an RICU can be successfully treated with NIV in these units. These results may be used to determine precise RICU admission criteria.

Impact of Early Non-Invasive Ventilation in Amyotrophic Lateral Sclerosis: A multicenter Randomized Controlled Trial.

BACKGROUND AND OBJECTIVE: Forced vital capacity (FVC) less than 50% of predicted is one of the main parameters used for Non-Invasive Ventilation (NIV) initiation in Amyotrophic Lateral Sclerosis (ALS). Recent studies suggest that higher values of FVC could be considered as a threshold. The aim of this study is to evaluate whether early use of NIV improves the prognosis of ALS patients compared with standard initiation. METHODS: This is a randomized, parallel, multicenter, open-label, controlled clinical trial, with recruitment at the ALS outpatient multidisciplinary units of six Spanish hospitals. Patients were included when their FVC reached the 75% threshold and were randomized by computer, stratifying by center in an allocation ratio of 1:1 to Early NIV (FVC below 75%) or Standard NIV (FVC below 50%) initiation. The primary outcome was time to death or tracheostomy.Trial registration number ClinicalTrials.gov: NCT01641965. RESULTS: Between May 2012 and June 2014, 42 patients were randomized to two groups, 20 to Early NIV and 22 to Standard NIV initiation. We found differences in survival in favor of the intervention group: an incidence of mortality (2.68 [1.87-5.50] vs. 3.33 [1.34-4.80] person-months) and a median survival (25.2 vs. 19.4 months), although without reaching statistical significance (p = 0.267). CONCLUSIONS: This trial did not reach the primary endpoint of survival; nevertheless, it is the first Randomized Controlled Trial (RCT) to demonstrate the benefits of early NIV in slowing the decline of respiratory muscle strength and reducing adverse events. Although not all the results reached statistical significance, all the analyzed data favor early NIV. In addition, this study demonstrates good tolerance and compliance with early NIV without quality of sleep impairment. These data reinforce the early respiratory evaluation of ALS patients and NIV initiation with an FVC of around 75%.

Predicting nocturnal hypoventilation in hypercapnic chronic obstructive pulmonary disease patients undergoing long-term oxygen therapy.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) patients are very sensitive to changes in pulmonary mechanics and central ventilation control during sleep and may develop significant gas exchange alterations with increased hypoxemia and hypercapnia. Oxygen therapy improves nocturnal desaturation but can worsen hypoventilation. OBJECTIVES: To analyze the prevalence of nocturnal hypoventilation (NHV) in hypercapnic COPD patients and to determine predictive factors for this phenomenon. METHODS: This was a prospective multicenter study which enrolled 80 clinically stable COPD patients with hypercapnic respiratory failure who fulfilled the conventional criteria for long-term oxygen therapy (LTOT). All patients had undergone pulmonary function testing, blood gas analysis, and respiratory polygraphy. Arterial blood gas samples were obtained while patients were awake and during sleep. NHV was considered when an increase in PaCO2 >10 mm Hg was observed in any nocturnal arterial blood gas sample as compared to the awake levels. RESULTS: Seventeen patients (21%) developed NHV. NHV was associated with the values of BMI, hemoglobin, hematocrits, DLCO, and PaO2 reached after oxygen administration. In the logistic regression analysis BMI (OR 1.26, 95% CI 1.068-1.481; p = 0.006) and the diurnal increase of PaO2 after O2 (OR 0.89, 95% CI 0.807-0.972; p = 0.010) were the variables that best discriminated with a sensitivity of 82% and a specificity of 78%. CONCLUSIONS: NHV is a relatively common finding in stable hypercapnic COPD patients undergoing LTOT and it is related to a higher BMI and lower PaO2 after oxygen administration.

Central apnea in a sporadic case of Creutzfeldt-Jakob disease with brainstem involvement.

We report a patient with Creutzfeldt-Jakob disease with somnolence as an initial manifestation and sleep apneas as a prominent sign. A respiratory polygraphy revealed the presence of a continuous Cheyne-Stokes pattern both awake and during sleep with central apneas. The neuropathology showed PrP deposition in brainstem involving respiratory nuclei. Central apnea is a rare manifestation of CJD that can be observed from early stages and may be related with PrP deposition in brainstem structures.

Survival benefit of multidisciplinary care in amyotrophic lateral sclerosis in Spain: association with noninvasive mechanical ventilation.

PURPOSE: Multidisciplinary care has become the preferred model of care for patients with amyotrophic lateral sclerosis (ALS). It is assumed that the sum of interventions associated with this approach has a positive effect on survival. The objective of the study was to evaluate the impact of a multidisciplinary care approach on the survival of patients with ALS. PATIENTS AND METHODS: We performed a retrospective review of prospectively collected data in a tertiary referral center in Spain. Participants were patients with definite or probable ALS managed in a multidisciplinary care program. We compared demographic and survival data of patients with definite or probable ALS treated in a referral center without and with implementation of a multidisciplinary care program. We performed time-dependent multivariate survival analysis of the use of noninvasive mechanical ventilation (NIMV) and gastrostomy. RESULTS: We evaluated 398 consecutive patients, of whom 54 were treated by a general neurologist and 344 were treated in the multidisciplinary care clinic. Patients receiving multidisciplinary care were older (62 vs 58 years), tended to have bulbar onset disease (30% vs 17.7%), and were more likely to receive riluzole (88.7% vs 29.6%, p<0.01), NIMV (48.8% vs 29.6%, p>0.001), and nutrition via gastrostomy (32.3% vs 3.7%, p<0.01). Kaplan-Meier analysis showed a 6-month increase in survival (log-rank, 16.03, p<0.001). Application of the Andersen-Gill model showed that the variables associated with reduced mortality were reduced time to NIMV and gastrostomy and the duration of both, thus reflecting compliance. CONCLUSIONS: Multidisciplinary care increased the survival of ALS patients in our study population. Timely use of respiratory support and gastrostomy are fundamental aspects of this benefit.

Outcome of non-invasive domiciliary ventilation in elderly patients.

STUDY OBJECTIVES: To analyze the short- and long-term effects of domiciliary non-invasive ventilation (NIV) in the elderly. METHODS: From 1990 to 2005 all patients who initiated NIV at age 75 or older were included in the study. The mean follow-up period was 36 (24) months. Data were obtained from a database record. RESULTS: Forty-three patients, mean age 77 (1.9) years and hypercapnic respiratory failure secondary to restrictive, neuromuscular or hypoventilatory disease were included. The short-term effects included a significant improvement in arterial blood gases and nocturnal desaturations during NIV compared to baseline: PaO(2) increased a mean of 19 mmHg (P<0.0001), PaCO(2) decreased a mean of 16 mmHg (P<0.0001) and nocturnal time with SaO(2)<90% decreased a mean of 72% (P<0.0001). Arterial blood gases while breathing room air also improved significantly at 6 months after NIV initiation. Five patients (11%) discontinued treatment; this group did not differ from patients who continued NIV. Mean compliance was 8.3 (3.1)h/day. In the long-term effects, we observed that the initial improvement of arterial blood gases breathing room air was maintained throughout the followup period. The number of hospital admissions and days of hospital stay decreased significantly (P<0.0001 and 0.001, respectively) after NIV initiation. The poorest survival was observed in ALS patients (median 10.9 (2.3) months) significantly lower than the survival for the other diagnostic groups (median 58.5 (4.8) months), P=0.0013. CONCLUSIONS: NIV is an effective treatment in the elderly. It improves arterial blood gases and nocturnal desaturations, decreases hospital admissions and is associated with long survival. So advanced age should not be considered as an exclusion criteria to prescribe NIV.

Transcutaneous Carbon Dioxide Monitoring in Subjects With Acute Respiratory Failure and Severe Hypercapnia.

BACKGROUND: Transcutaneous carbon dioxide (P(tcCO2)) monitoring is being used increasingly to assess acute respiratory failure. However, there are conflicting findings concerning its reliability when evaluating patients with high levels of P(aCO2). Our study evaluates the accuracy of this method in subjects with respiratory failure according to the severity of hypercapnia. METHODS: We included subjects with respiratory failure, admitted to a respiratory intermediate care unit, who required arterial blood gas analysis. Simultaneously, P(tcCO2) was measured using a digital monitor. Relations between P(aCO2) and P(tcCO2) were assessed by the Pearson correlation coefficient. Bland-Altman analysis was used to test data dispersion, and an analysis of variance test was used to compare the differences between P(aCO2) and the corresponding P(tcCO2) at different levels (level 1, <50 mm Hg; level 2, 50-60 mm Hg; level 3, >60 mm Hg). RESULTS: Eighty-one subjects were analyzed. The main diagnosis was COPD exacerbation (45%). P(tcCO2) correlated well with P(aCO2) (r2 = 0.93, P < .001). Bland-Altman analysis showed a mean P(aCO2) - P(tcCO2) difference of 4.9 ± 4.4 with 95% limits of agreement ranging from -3.6 to 13.4. The difference between variables increased in line with P(aCO2) severity: level 1, 1.7 ± 3.2 mm Hg; level 2, 3.7 ± 2.8; level 3, 6.8 ± 4.7 (analysis of variance, P < .001). CONCLUSIONS: Our study showed an acceptable agreement of P(tcCO2) monitoring with arterial blood gas analysis. However, we should consider that P(tcCO2) underestimates P(aCO2) levels, and its accuracy depends on the level of hypercapnia, so this method would not be suitable for acute patients with severe hypercapnia.

Survival in amyotrophic lateral sclerosis with home mechanical ventilation: the impact of systematic respiratory assessment and bulbar involvement.

STUDY OBJECTIVES: To analyze (1) the impact of a protocol of early respiratory evaluation of the indications for home mechanical ventilation (HMV) in patients with amyotrophic lateral sclerosis (ALS), and (2) the effects of the protocol and of bulbar involvement on the survival of patients receiving noninvasive ventilation (NIV). DESIGN AND SETTING: Retrospective study in a tertiary care referral center. PATIENTS: HMV was indicated in 86 patients with ALS, with 22 patients (25%) presenting with intolerance to treatment associated with bulbar involvement. Treatment with HMV had been initiated in 15 of 64 patients prior to initiating the protocol (group A) and in the remaining 49 patients after protocol initiation (group B). RESULTS: In group A, the majority of patients began treatment with HMV during an acute episode requiring ICU admission (p = 0.001) and tracheal ventilation (p = 0.025), with a lower percentage of patients beginning HMV treatment without respiratory insufficiency (p = 0.013). No significant differences in survival rates were found between groups A and B among patients treated with NIV. Greater survival was observed in group B (p = 0.03) when patients with bulbar involvement were excluded (96%). Patients without bulbar involvement at the start of therapy with NIV presented a significantly better survival rate (p = 0.03). Multivariate analysis showed bulbar involvement to be an independent prognostic factor for survival (relative risk, 1.6; 95% confidence interval, 1.01 to 2.54; p = 0.04). No significant differences in survival were observed between patients with bulbar involvement following treatment with NIV and those with intolerance, except for the subgroup of patients who began NIV treatment with hypercapnia (p = 0.0002). CONCLUSIONS: Early systematic respiratory evaluation in patients with ALS is necessary to improve the results of HMV. Further studies are required to confirm the benefits of NIV treatment in patients with bulbar involvement, especially in the early stages.