measuring-diaphragm-thickness-function-using-point-care

Measuring Diaphragm Thickness and Function Using Point-of-Care Ultrasound

The diaphragm is the main component of the respiratory muscle pump. Diaphragm dysfunction can cause dyspnea and exercise intolerance, and predisposes ...

University of Toronto

Nepean Hospital

What Can We Learn From Monitoring Diaphragm Activity in Infants?

Transvenous Phrenic Nerve Stimulation: A Novel Therapy Gathering Pace.

Phrenic nerve stimulation to protect the diaphragm, lung, and brain during mechanical ventilation.

ICU clinicians rely on bedside physiological measurements to inform many routine clinical decisions. Because deranged physiology is usually associated with poor clinical outcomes, it is tempting to hypothesize that manipulating and intervening on physiological parameters might improve outcomes for patients. However, testing these hypotheses through mathematical models of the relationship between physiology and outcomes presents a number of important methodological challenges. These models reflect the theories of the researcher and can therefore be heavily influenced by one's assumptions and background beliefs. Model building must therefore be approached with great care and forethought, because failure to consider relevant sources of measurement error, confounding, coupling, and time dependency or failure to assess the direction of causality for associations of interest before modeling may give rise to spurious results. This paper outlines the main challenges in analyzing and interpreting these models and offers potential solutions to address these challenges.

Linking Acute Physiology to Outcomes in the ICU: Challenges and Solutions for Research.

Diaphragm neurostimulation consists of placing electrodes directly on or in proximity to the phrenic nerve(s) to elicit diaphragmatic contractions. Since its initial description in the 18th century, indications have shifted from cardiopulmonary resuscitation to long-term ventilatory support. Recently, the technical development of devices for temporary diaphragm neurostimulation has opened up the possibility of a new era for the management of mechanically ventilated patients. Combining positive pressure ventilation with diaphragm neurostimulation offers a potentially promising new approach to the delivery of mechanical ventilation which may benefit multiple organ systems. Maintaining diaphragm contractions during ventilation may attenuate diaphragm atrophy and accelerate weaning from mechanical ventilation. Preventing atelectasis and preserving lung volume can reduce lung stress and strain and improve homogeneity of ventilation, potentially mitigating ventilator-induced lung injury. Furthermore, restoring the thoracoabdominal pressure gradient generated by diaphragm contractions may attenuate the drop in cardiac output induced by positive pressure ventilation. Experimental evidence suggests diaphragm neurostimulation may prevent neuroinflammation associated with mechanical ventilation. This review describes the historical development and evolving approaches to diaphragm neurostimulation during mechanical ventilation and surveys the potential mechanisms of benefit. The review proposes a research agenda and offers perspectives for the future of diaphragm neurostimulation assisted mechanical ventilation for critically ill patients.

Diaphragm Neurostimulation Assisted Ventilation in Critically Ill Patients.

Reply to Fernández.

Proof of Concept for Continuous On-Demand Phrenic Nerve Stimulation to Prevent Diaphragm Disuse during Mechanical Ventilation (STIMULUS): A Phase 1 Clinical Trial.

Diaphragm inactivity during invasive mechanical ventilation leads to diaphragm atrophy and weakness, hemodynamic instability, and ventilatory heterogeneity. Absent respiratory drive and effort can, therefore, worsen injury to both lung and diaphragm and is a major cause of failure to wean. Phrenic nerve stimulation (PNS) can maintain controlled levels of diaphragm activity independent of intrinsic drive and as such may offer a promising approach to achieving lung and diaphragm protective ventilatory targets. Whereas PNS has an established role in the management of chronic respiratory failure, there is emerging interest in how its multisystem putative benefits may be temporarily harnessed in the management of invasively ventilated patients with acute respiratory failure.

Article	Year
What Can We Learn From Monitoring Diaphragm Activity in Infants? Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies\| PubMed ID: 34734896	2021
Transvenous Phrenic Nerve Stimulation: A Novel Therapy Gathering Pace. American journal of respiratory and critical care medicine\| PubMed ID: 35320061	2022
Phrenic nerve stimulation to protect the diaphragm, lung, and brain during mechanical ventilation. Intensive care medicine\| PubMed ID: 35688993	2022
Linking Acute Physiology to Outcomes in the ICU: Challenges and Solutions for Research. American journal of respiratory and critical care medicine\| PubMed ID: 36705985	2023
Diaphragm Neurostimulation Assisted Ventilation in Critically Ill Patients. American journal of respiratory and critical care medicine\| PubMed ID: 36917765	2023
Reply to Fernández. American journal of respiratory and critical care medicine\| PubMed ID: 37159944	2023
Proof of Concept for Continuous On-Demand Phrenic Nerve Stimulation to Prevent Diaphragm Disuse during Mechanical Ventilation (STIMULUS): A Phase 1 Clinical Trial. American journal of respiratory and critical care medicine\| PubMed ID: 37642635	2023
Phrenic Nerve Stimulation for Acute Respiratory Failure. Respiratory care\| PubMed ID: 37875317	2023

Idunn S. Morris

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