Prevalence and time-course of diaphragmatic dysfunction following lung resection: A repeated ultrasonic assessment

Exploring ultrasonographic diaphragmatic function in perioperative anesthesia setting: A comprehensive narrative review

The ultrasound study of diaphragm function represents a valid method that has been extensively studied in recent decades in various fields, especially in intensive care, emergency, and pulmonology settings. Diaphragmatic function is pivotal in these contexts due to its crucial role in respiratory mechanics, ventilation support strategies, and overall patient respiratory outcomes. Dysfunction or weakness of the diaphragm can lead to respiratory failure, ventilatory insufficiency, and prolonged mechanical ventilation, making its assessment essential for patient management and prognosis in critical care and emergency medicine. While several studies have focused on diaphragmatic functionality in the context of intensive care, there has been limited attention within the field of anesthesia. The ultrasound aids in assessing diaphragmatic dysfunction (DD) by measuring muscle mass and contractility and their potential variations over time. Recent advancements in ultrasound imaging allow clinicians to evaluate diaphragm function and monitor it during mechanical ventilation more easily. In the context of anesthesia, early studies have shed light on the patho-physiological mechanisms of diaphragm function during general anesthesia. In contrast, more recent research has centered on evaluating diaphragmatic functionality at various phases of general anesthesia and by comparing diverse types of procedures or anatomical position during surgery. The objectives of this current review are to highlight the use of diaphragm ultrasound for the evaluation of diaphragmatic function during perioperative anesthesia and surgery. Specifically, we aim to examine the effects of anesthetic agents, surgical techniques, and anatomical positioning on diaphragmatic function. We explore how ultrasound aids in assessing DD by measuring muscle mass and contractility, as well as their potential variations over time. Additionally, we will discuss recent advancements in ultrasound imaging that allow clinicians to evaluate diaphragm function and monitor it during mechanical ventilation more easily.

Ultrasound assessment of diaphragmatic dysfunction in non-critically ill patients: relevant indicators and update

Diaphragm dysfunction (DD) can be classified as mild, resulting in diaphragmatic weakness, or severe, resulting in diaphragmatic paralysis. Various factors such as prolonged mechanical ventilation, surgical trauma, and inflammation can cause diaphragmatic injury, leading to negative outcomes for patients, including extended bed rest and increased risk of pulmonary complications. Therefore, it is crucial to protect and monitor diaphragmatic function. Impaired diaphragmatic function directly impacts ventilation, as the diaphragm is the primary muscle involved in inhalation. Even unilateral DD can cause ventilation abnormalities, which in turn lead to impaired gas exchange, this makes weaning from mechanical ventilation challenging and contributes to a higher incidence of ventilator-induced diaphragm dysfunction and prolonged ICU stays. However, there is insufficient research on DD in non-ICU patients, and DD can occur in all phases of the perioperative period. Furthermore, the current literature lacks standardized ultrasound indicators and diagnostic criteria for assessing diaphragmatic dysfunction. As a result, the full potential of diaphragmatic ultrasound parameters in quickly and accurately assessing diaphragmatic function and guiding diagnostic and therapeutic decisions has not been realized.

Perioperative Diaphragm Dysfunction

Diaphragm Dysfunction (DD) is a respiratory disorder with multiple causes. Although both unilateral and bilateral DD could ultimately lead to respiratory failure, the former is more common. Increasing research has recently delved into perioperative diaphragm protection. It has been established that DD promotes atelectasis development by affecting lung and chest wall mechanics. Diaphragm function must be specifically assessed for clinicians to optimally select an anesthetic approach, prepare for adequate monitoring, and implement the perioperative plan. Recent technological advancements, including dynamic MRI, ultrasound, and esophageal manometry, have critically aided disease diagnosis and management. In this context, it is noteworthy that therapeutic approaches for DD vary depending on its etiology and include various interventions, either noninvasive or invasive, aimed at promoting diaphragm recruitment. This review aims to unravel alternative anesthetic and operative strategies that minimize postoperative dysfunction by elucidating the identification of patients at a higher risk of DD and procedures that could cause postoperative DD, facilitating the recognition and avoidance of anesthetic and surgical interventions likely to impair diaphragmatic function.

Changes in diaphragmatic ultrasonography findings and their association with postoperative complications in children undergoing pulmonary resection: A single-centre, prospective, observational study

BACKGROUND

Few studies have investigated the changes in diaphragmatic function and their association with postoperative pulmonary complications (PPCs) in paediatric patients after lung resection.

OBJECTIVE

This study aimed to evaluate diaphragmatic function using ultrasound after lung resection and its influence on PCCs in children.

DESIGN

Prospective observational study.

SETTING

A tertiary children's hospital.

PATIENTS

Children aged 6 years or less who were scheduled for video-assisted thoracoscopic lung resection.

INTERVENTION

Ultrasonographic measurements of diaphragmatic excursion (DE) and thickening fraction (TF) were performed for three epochs: before anaesthesia induction (T0), 1 h postoperatively (T1) and 24 h postoperatively (T2). The thickening fraction is calculated from the thickness of the diaphragm at end expiration and end inspiration at each time point. DE T1 /DE T0 , DE T2 /DE T0 , TF T1 /TF T0 and TF T2 /TF T0 (%) were calculated. The incidence of PCCs was also determined.

MAIN OUTCOME MEASURES

The primary outcomes were changes in diaphragmatic excursion and thickening fraction over time, from T0 to T2. The secondary outcomes were the association between ultrasound parameters of diaphragm function and the occurrence of early PPCs within 3 days.

RESULTS

Data from 74 children were analysed. On the operated side, both diaphragmatic excursion and thickening fraction decreased at T1 and recovered slightly at T2, and were significantly lower than the T0 values. Children with PPCs had significantly lower DE T2 /DE T0 and TF T2 /TF T0 scores on the operated side than those without PPCs. According to the receiver operating characteristic analysis, the DE T2 /DE T0 (< 61.1%) on the operated side was associated with PPCs with an area under the curve of 0.764.

CONCLUSIONS

Peri-operative diaphragmatic function assessed by ultrasonography changed after lung resection in children. The diaphragmatic excursion and thickening fraction decreased postoperatively, and a prolonged decrease in diaphragmatic excursion was associated with pulmonary complications after lung surgery in children.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov, NCT04400370.