Management of pregnant women in tertiary maternity hospitals in the Paris area referred to the intensive care unit for acute hypoxaemic respiratory failure related to SARS-CoV-2: which practices for which outcomes?

BACKGROUND: Evidence for the management of pregnant women with acute hypoxaemic respiratory failure (AHRF) is currently lacking. The likelihood of avoiding intubation and the risks of continuing the pregnancy under invasive ventilation remain undetermined. We report the management and outcome of pregnant women with pneumonia related to SARS-CoV-2 admitted to the ICU of tertiary maternity hospitals of the Paris area. METHODS: We studied a retrospective cohort of pregnant women admitted to 15 ICUs with AHRF related to SARS-CoV-2 defined by the need for O2 ≥ 6 L/min, high-flow nasal oxygen (HFNO), non-invasive or invasive ventilation. Trajectories were assessed to determine the need for intubation and the possibility of continuing the pregnancy on invasive ventilation. RESULTS: One hundred and seven pregnant women, 34 (IQR: 30-38) years old, at a gestational age of 27 (IQR: 25-30) weeks were included. Obesity was present in 37/107. Intubation was required in 47/107 (44%). Intubation rate according to respiratory support was 14/19 (74%) for standard O2, 17/36 (47%) for non-invasive ventilation and 16/52 (31%) for HFNO. Factors significantly associated with intubation were pulmonary co-infection: adjusted OR: 3.38 (95% CI 1.31-9.21), HFNO: 0.11 (0.02-0.41) and non-invasive ventilation: 0.20 (0.04-0.80). Forty-six (43%) women were delivered during ICU stay, 39/46 (85%) for maternal pulmonary worsening, 41/46 (89%) at a preterm stage. Fourteen non-intubated women were delivered under regional anaesthesia; 9/14 ultimately required emergency intubation. Four different trajectories were identified: 19 women were delivered within 2 days after ICU admission while not intubated (12 required prolonged intubation), 23 women were delivered within 2 days after intubation, in 11 intubated women pregnancy was continued allowing delivery after ICU discharge in 8/11, 54 women were never intubated (53 were delivered after discharge). Timing of delivery after intubation was mainly dictated by gestational age. One maternal death and one foetal death were recorded. CONCLUSION: In pregnant women with AHRF related to SARS-CoV-2, HFNO and non-invasive mechanical ventilation were associated with a reduced rate of intubation, while pulmonary co-infection was associated with an increased rate. Pregnancy was continued on invasive mechanical ventilation in one-third of intubated women. Study registration retrospectively registered in ClinicalTrials (NCT05193526).

Comparison of high-flow nasal oxygen therapy and non-invasive ventilation in ICU patients with acute respiratory failure and a do-not-intubate orders: a multicentre prospective study OXYPAL.

INTRODUCTION: A palliative approach to intensive care unit (ICU) patients with acute respiratory failure and a do-not-intubate order corresponds to a poorly evaluated target for non-invasive oxygenation treatments. Survival alone should not be the only target; it also matters to avoid discomfort and to restore the patient's quality of life. We aim to conduct a prospective multicentre observational study to analyse clinical practices and their impact on outcomes of palliative high-flow nasal oxygen therapy (HFOT) and non-invasive ventilation (NIV) in ICU patients with do-not-intubate orders. METHODS AND ANALYSIS: This is an investigator-initiated, multicentre prospective observational cohort study comparing the three following strategies of oxygenation: HFOT alone, NIV alternating with HFOT and NIV alternating with standard oxygen in patients admitted in the ICU for acute respiratory failure with a do-not-intubate order. The primary outcome is the hospital survival within 14 days after ICU admission in patients weaned from NIV and HFOT. The sample size was estimated at a minimum of 330 patients divided into three groups according to the oxygenation strategy applied. The analysis takes into account confounding factors by modelling a propensity score. ETHICS AND DISSEMINATION: The study has been approved by the ethics committee and patients will be included after informed consent. The results will be submitted for publication in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT03673631.

Usefulness of Parasternal Intercostal Muscle Ultrasound during Weaning from Mechanical Ventilation.

BACKGROUND: The assessment of diaphragm function with diaphragm ultrasound seems to bring important clinical information to describe diaphragm work and weakness. When the diaphragm is weak, extradiaphragmatic muscles may play an important role, but whether ultrasound can also assess their activity and function is unknown. This study aimed to (1) evaluate the feasibility of measuring the thickening of the parasternal intercostal and investigate the responsiveness of this muscle to assisted ventilation; and (2) evaluate whether a combined evaluation of the parasternal and the diaphragm could predict failure of a spontaneous breathing trial. METHODS: First, an exploratory evaluation of the parasternal in 23 healthy subjects. Second, the responsiveness of parasternal to several pressure support levels were studied in 16 patients. Last, parasternal activity was compared in presence or absence of diaphragm dysfunction (assessed by magnetic stimulation of the phrenic nerves and ultrasound) and in case of success/failure of a spontaneous breathing trial in 54 patients. RESULTS: The parasternal was easily accessible in all patients. The interobserver reproducibility was good (intraclass correlation coefficient, 0.77 (95% CI, 0.53 to 0.89). There was a progressive decrease in parasternal muscle thickening fraction with increasing levels of pressure support (Spearman ρ = -0.61 [95% CI, -0.74 to -0.44]; P < 0.0001) and an inverse correlation between parasternal muscle thickening fraction and the pressure generating capacity of the diaphragm (Spearman ρ = -0.79 [95% CI, -0.87 to -0.66]; P < 0.0001). The parasternal muscle thickening fraction was higher in patients with diaphragm dysfunction: 17% (10 to 25) versus 5% (3 to 8), P < 0.0001. The pressure generating capacity of the diaphragm, the diaphragm thickening fraction and the parasternal thickening fraction similarly predicted failure or the spontaneous breathing trial. CONCLUSIONS: Ultrasound assessment of the parasternal intercostal muscle is feasible in the intensive care unit and provides novel information regarding the respiratory capacity load balance.

Adjusting ventilator settings to relieve dyspnoea modifies brain activity in critically ill patients: an electroencephalogram pilot study.

Dyspnoea is frequent and distressing in patients receiving mechanical ventilation, but it is often not properly evaluated by caregivers. Electroencephalographic signatures of dyspnoea have been identified experimentally in healthy subjects. We hypothesized that adjusting ventilator settings to relieve dyspnoea in MV patients would induce EEG changes. This was a first-of-its-kind observational study in a convenience population of 12 dyspnoeic, mechanically ventilated patients for whom a decision to adjust the ventilator settings was taken by the physician in charge (adjustments of pressure support, slope, or trigger). Pre- and post-ventilator adjustment electroencephalogram recordings were processed using covariance matrix statistical classifiers and pre-inspiratory potentials. The pre-ventilator adjustment median dyspnoea visual analogue scale was 3.0 (interquartile range: 2.5-4.0; minimum-maximum: 1-5) and decreased by (median) 3.0 post-ventilator adjustment. Statistical classifiers adequately detected electroencephalographic changes in 8 cases (area under the curve ≥0.7). Previously present pre-inspiratory potentials disappeared in 7 cases post-ventilator adjustment. Dyspnoea improvement was consistent with electroencephalographic changes in 9 cases. Adjusting ventilator settings to relieve dyspnoea produced detectable changes in brain activity. This paves the way for studies aimed at determining whether monitoring respiratory-related electroencephalographic activity can improve outcomes in critically ill patients under mechanical ventilation.

Postoperative outcomes of frequent exacerbator patients with Chronic Obstructive Pulmonary Disease after resection of Non-Small Cells Lung Cancer.

Chronic obstructive pulmonary disease (COPD) is a risk factor of post-operative complications after lung cancer resection. The influence of the "frequent exacerbator (FE)" phenotype (at least three exacerbations per year) is unknown. Postoperative outcomes of frequent exacerbators (POFE) was a prospective observational study of patients with COPD undergoing lung resection for cancer. The inclusion criteria were: age >40 years, FEV1/FVC <70%, non-urgent surgery for lung cancer, filled out self-questionnaires. The primary outcome was assessment of postoperative pulmonary complications (purulent tracheobronchitis, atelectasis, pneumonia, acute respiratory failure, need of mechanical ventilation). Secondary outcomes encompassed the prevalence of the FE phenotype and its impact on postoperative complications. A total of 682 patients were screened from June 2014 to October 2015. 93 patients with COPD were included, 21 (23%) were FE. Postoperative tracheobronchitis, atelectasis pneumonia or respiratory failure (isolated or associated) occurred in 47%, 48%, 26%, and 38% of patients, respectively. Non-invasive and invasive mechanical ventilation were necessary in 4 (4%) and 22 (23%) patients. Purulent tracheobronchitis, pneumonia and hypercapnia (this last requiring noninvasive mechanical ventilation) were more frequent in FE (p = 0.043, 0.042, 0.015); however the number of patients wth at least one respiratory complication was not different (76% vs. 52%, p = 0.056). In all patients, multivariate logistic regression identified two independent factors of postoperative respiratory complications: male sex (OR 10.6 [95% CI 1.97-57.6], p = 0.006) and the FE phenotype (OR 6.33 [1.04-38.39], p = 0.045). Occurrence of postoperative complications in patients with COPD is high. FE phenotype is an independent risk factor.

Ultrasound evaluation of diaphragm function in mechanically ventilated patients: comparison to phrenic stimulation and prognostic implications.

RATIONALE: In intensive care unit (ICU) patients, diaphragm dysfunction is associated with adverse clinical outcomes. Ultrasound measurements of diaphragm thickness, excursion (EXdi) and thickening fraction (TFdi) are putative estimators of diaphragm function, but have never been compared with phrenic nerve stimulation. Our aim was to describe the relationship between these variables and diaphragm function evaluated using the change in endotracheal pressure after phrenic nerve stimulation (Ptr,stim), and to compare their prognostic value. METHODS: Between November 2014 and June 2015, Ptr,stim and ultrasound variables were measured in mechanically ventilated patients <24 hours after intubation ('initiation of mechanical ventilation (MV)', under assist-control ventilation, ACV) and at the time of switch to pressure support ventilation ('switch to PSV'), and compared using Spearman's correlation and receiver operating characteristic curve analysis. Diaphragm dysfunction was defined as Ptr,stim <11 cm H2O. RESULTS: 112 patients were included. At initiation of MV, Ptr,stim was not correlated to diaphragm thickness (p=0.28), EXdi (p=0.66) or TFdi (p=0.80). At switch to PSV, TFdi and EXdi were respectively very strongly and moderately correlated to Ptr,stim, (r=0.87, p<0.001 and 0.45, p=0.001), but diaphragm thickness was not (p=0.45). A TFdi <29% could reliably identify diaphragm dysfunction (sensitivity and specificity of 85% and 88%), but diaphragm thickness and EXdi could not. This value was associated with increased duration of ICU stay and MV, and mortality. CONCLUSIONS: Under ACV, diaphragm thickness, EXdi and TFdi were uncorrelated to Ptr,stim. Under PSV, TFdi was strongly correlated to diaphragm strength and both were predictors of remaining length of MV and ICU and hospital death.

When Breathing Interferes with Cognition: Experimental Inspiratory Loading Alters Timed Up-and-Go Test in Normal Humans.

Human breathing stems from automatic brainstem neural processes. It can also be operated by cortico-subcortical networks, especially when breathing becomes uncomfortable because of external or internal inspiratory loads. How the "irruption of breathing into consciousness" interacts with cognition remains unclear, but a case report in a patient with defective automatic breathing (Ondine's curse syndrome) has shown that there was a cognitive cost of breathing when the respiratory cortical networks were engaged. In a pilot study of putative breathing-cognition interactions, the present study relied on a randomized design to test the hypothesis that experimentally loaded breathing in 28 young healthy subjects would have a negative impact on cognition as tested by "timed up-and-go" test (TUG) and its imagery version (iTUG). Progressive inspiratory threshold loading resulted in slower TUG and iTUG performance. Participants consistently imagined themselves faster than they actually were. However, progressive inspiratory loading slowed iTUG more than TUG, a finding that is unexpected with regard to the known effects of dual tasking on TUG and iTUG (slower TUG but stable iTUG). Insofar as the cortical networks engaged in response to inspiratory loading are also activated during complex locomotor tasks requiring cognitive inputs, we infer that competition for cortical resources may account for the breathing-cognition interference that is evidenced here.