Respiratory Drive in Critically Ill Patients. Pathophysiology and Clinical Implications

Vaporidi, Katerina; Akoumianaki, Evangelia; Telias, Irene; Goligher, Ewan C.; Brochard, Laurent; Georgopoulos, Dimitris

doi:10.1164/rccm.201903-0596so

Cited by 187 publications

(265 citation statements)

References 115 publications

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“…Vasoplegia accounts for severe hypoxemia. The normal response to hypoxemia is to increase minute ventilation, primarily by increasing the tidal volume [7] (up to 15-20 ml/ kg), which is associated with a more negative intrathoracic inspiratory pressure. Undetermined factors other than hypoxemia markedly stimulate, in these patients, the respiratory drive.…”

Section: Covid-19 Pneumonia Type Lmentioning

confidence: 99%

COVID-19 pneumonia: different respiratory treatments for different phenotypes?

et al. 2020

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Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19) has spread to almost 100 countries, infected over 10M patients and resulted in 505K deaths worldwide as of 30 th June 2020. The major clinical feature of severe COVID-19 requiring ventilation is acute Respiratory Distress Syndrome (ARDS) with multi-functional failure as a result of a cytokine storm with increased serum levels of cytokines. The pathogenesis of the respiratory failure in COVID-19 is yet unknown, but diffuse alveolar damage with interstitial thickening leading to compromised gas exchange is a plausible mechanism. Hypoxia has been seen in the COVID-19 patients however, patients present with a distinct phenotype. Intracellular levels of NO playing important role in the vasodilation of small vessels. Objectives: To elucidate the intracellular levels of NO inside of RBCs in COVID-19 patients compared with that of healthy control subjects. Methods: We recruited 14 COVID-19 infected cases who had pulmonary involvement of their disease, 4 non-COVID-19 healthy controls (without pulmonary involvement and were not hypoxic) and 2 hypoxic non-COVID-19 patients subjects who presented at the Masih Daneshvari Hospital of Tehran, Iran between March-May 2020. Whole blood samples were harvested from patients and intracellular levels of NO in 1 million red blood cells (RBC) was measured by DAF staining using ow cytometry (FACS Calibour, BD, CA, USA). Results: The Mean orescent of intensity for NO was signi cantly enhanced in COVID-19 patients compared with healthy control subjects (P≤0.05). As a further control for whether hypoxia induced this higher intracellular NO, we evaluated the levels of NO inside RBC of hypoxic patients. No signi cant differences in NO levels were seen between the hypoxic and non-hypoxic control group. Conclusions: This pilot study demonstrates increased levels of intracellular NO in RBCs from COVID-19 patients. Future studies should examine whether intracellular NO would be increased in large number of COVID-19 patients for usage of possible NO therapy in severe patients.

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Section: Covid-19 Pneumonia Type Lmentioning

confidence: 99%

COVID-19 pneumonia: different respiratory treatments for different phenotypes?

et al. 2020

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“…This may be potentially relevant in the context of increasing awareness of the adverse effects of both strong and weak respiratory efforts during mechanical ventilation on patient outcomes. 40 Since monitoring patient inspiratory effort is rarely done in routine because it requires an invasive procedure (esophageal catheter), performing parasternal intercostal ultrasound could be an alternative approach to provide a qualitative estimate of high inspiratory effort.…”

Section: Parasternal Intercostal Muscle Thickening Diaphragm Thickenmentioning

confidence: 99%

Usefulness of Parasternal Intercostal Muscle Ultrasound during Weaning from Mechanical Ventilation

et al. 2020

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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. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

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“…As such, high dP di /dt values reflect high respiratory drive. In healthy subjects, dP di /dt values of 5 cmH 2 O/s are observed during quiet breathing [4]. dP di /dt is often normalized to the maximum P di , but maximum inspiratory maneuvers are rarely feasible in ventilated ICU patients.…”

Section: Inspiratory Effortmentioning

confidence: 99%