Respiratory therapists possess the technical expertise to administer point-of-care lung ultrasound, which is becoming a preferred imaging option at the patient’s bedside — particularly for the critically ill patient.
by Paul Nuccio, MS, RRT, FAARC
The importance of performing diagnostic procedures and therapeutic interventions in the critically ill patient cannot be overemphasized. The availability of these important services must be both timely and accurate. Anything less would be providing patients with sub-optimal care at a time when they need high-quality care the most.
Clinicians who provide critical care services have become quite familiar with the use of the portable chest radiograph to assess a patient’s cardiopulmonary function. There have been numerous studies that question its clinical efficacy, and its apparent usefulness has been waning.1 Once considered to be somewhat of a standard for providing diagnostic information in the ICU, the so-called gold standard for providing both diagnostic and therapeutic services to evaluate lung function now belongs to computed tomography, or CT scanning.2 Although CT scanning does a superb job of helping with diagnostic and therapeutic interventions, in many, if not most hospitals, patients need to be transported away from the ICU in order to undergo testing, thus being transported with a ventilator and significant monitoring equipment as well as personnel, making it often an undesirable or difficult venture.3 The performance of lung ultrasound at the patient’s bedside has begun to be seen as a more preferable option, particularly for the critically ill patient.
Past & Present Practices
Chest radiography has been available since the late 1800’s, with the portable x-ray units following in the early 1900’s. Portable chest x-rays (CXR) can easily help the physician to diagnose certain conditions such as tumors or consolidation. They produce a medium image quality which is usually considered to be acceptable. It does however produce a certain amount of radiation exposure, which can be quite problematic.4
Computed tomography, or CT scanning, was developed in the 1960’s & 1970’s. This scanning technique produces high quality images and can be performed relatively quickly. They too produce radiation exposure to both patients and caregivers,5 and often requires the patient to be transported to a different area of the hospital for studies to be performed, not a simple task when associated with a critically ill patient.2
Other diagnostic testing techniques are also utilized such as spirometry and other pulmonary function testing, bronchoalveolar lavage with bronchoscopy, and arterial blood gas sampling, each having their own sets of benefits and potential complications. Mechanical ventilators have become more complex, providing the clinician with the benefits of enhanced monitoring, both with data and with the graphical analysis of every breath.
In more recent years, respiratory therapists have become involved with the use and performance of esophageal balloon manometry and the creation of pressure-volume curves to help assess lung recruitability. Each of these techniques requires specialized training to ensure that the procedures are carried out both safely and effectively.
The purpose of this article is to focus on a newer technology that has begun being used at the bedside of critically ill patients called lung ultrasound.
Lung Ultrasound at the Bedside
Lung ultrasound is similar to other types of ultrasound procedures where sound waves are generated and used to evaluate certain parts of the body. Since these sound waves are normally not transmitted through structures that are filled with air, such as the lungs, the lung parenchyma is not normally visualized beyond the pleura. However, because certain injuries to the lung creates an abnormal gas/tissue interface, artifacts will be produced. These artifacts make it possible for lung ultrasound to accurately assess lung aeration in patients who have acute lung injury.
Benefits of Using Lung Ultrasound
Many of the conditions that lead to severe shortness of breath, such as pulmonary edema, pleural effusion, pneumothorax, and pneumonia, have very distinct sonographic appearances, enabling both a rapid and accurate bedside identification of the condition.
Compared to the previously mentioned diagnostic tests, lung ultrasound may be made readily available at a moment’s notice right at the patient’s bedside, or at the point of care (POC). It has the ability to be performed at any time of the day or night and can pretty much provide instantaneous results.
Considered to be a non-critical and non-invasive device given that the only contact with a patient is on intact skin, ultrasound machines only require low-level disinfection, unlike other equipment such as fiberoptic bronchoscopes which necessitate high-level disinfection procedures.6
Why Respiratory Therapists?
A thorough understanding of the anatomy of the chest wall and the respiratory system is critical in being able to perform lung ultrasound and interpret its findings. (See Figures 1 & 2). Respiratory therapists are present in the critical care areas of a hospital 24/7. RT’s are known to have superior technical skills and are highly educated in the anatomy and physiology of the cardiopulmonary system. Given that RT’s have not commonly performed such lung ultrasound procedures, questions still arise as to the necessary training requirements, and the type of training formats that will provide the best outcomes. There is currently not a consensus as to the number of supervised procedures an RT would need to perform prior to being deemed competent. However, with the proper training, respiratory therapists have demonstrated the ability to perform these tests with a high degree of competency and accuracy, in some cases after the performance of as few as ten supervised procedures.7
There are now advanced respiratory care programs who have incorporated lung ultrasound into their curriculum, along with other advanced techniques as the profession of Respiratory Care continues to evolve and expand.
A standard training curriculum for educating respiratory therapists or others on the use of bedside lung ultrasound has not been clearly established. There have however, been programs that have been developed that have demonstrated the successful implementation of this technology by previously untrained professionals. Most programs begin with a period of self-study, which may include reading materials and observing video presentations. Having access to a high-fidelity simulation center could further enhance this training, prior to and in addition to live, supervised testing at the bedside.
In one study that evaluated the training requirements specifically for respiratory therapists, the researchers found that after performing only ten ultrasound scans, fewer that 2% required assistance and fewer that 5% were interpreted incorrectly by the respiratory therapist.7
Lung Ultrasound & COVID-19
In several studies that were outlined in a recent editorial, lung ultrasound was shown to be of comparable value to that of computerized tomography (CT), as both a great diagnostic tool as well as a monitoring tool for prognostic disease progression purposes.8 It was also found to be a valuable technology to identify patients who might require Extracorporeal Membrane Oxygenation (ECMO) support. Given the ease of both accessibility and assessibility of lung ultrasound, it can easily be implemented into safety protocols when dealing with patients who may be suffering from COVID-19.
Company & Equipment Support
Since any medical equipment that is used to aid with patient diagnosis and evaluation must possess a high degree of accuracy and reliability, it is important to not only closely evaluate such a device prior to purchase, but also assess the training and support that will be provided by the individual company. One particular company, Philips Healthcare, provides a plethora of educational materials such as videos, enabling the clinician to view specific anatomical abnormalities prior to performing any procedures. One particular system that this company offers is called the Lumify which has various probes, depending on what type of imaging is to be performed. Each of these probes can be connected to hand-held devices, such as a smart tablet or even a smart phone, making these devices quite portable and convenient.
Since respiratory therapists are innately accustomed to providing professional services at the patient’s bedside day and night, and they tend to be quite technologically savvy as well as clinically competent, they can clearly provide value which is measurable by how quickly and accurately they can provide services to the patient and by how quickly the patient can be successfully discharged from the intensive care unit (ICU) and ultimately from the hospital. Providing a diagnostic service right at the point of care, which can be performed immediately around the clock, combined with other monitoring data such as real-time ventilator information and graphics and other available patient monitoring data will likely lead to improved patient outcomes.
Approximately 15-20 years ago the AARC embarked on developing a vision for Respiratory Therapists in 2015 and Beyond. This author can specifically recall listening to lectures on this topic presented by the late Robert Kacmarek, who spoke quite clearly and eloquently about the importance of RT’s and their expanding roles involving advanced monitoring at the bedside of the critically ill patient. In one of the Consensus Conferences that followed, it was stated that “Essential to the care of critically ill patients is a broad knowledge of the various approaches to monitoring. This includes laboratory, radiograph, computed tomography, and magnetic resonance imaging data, and bedside monitoring data.”9 It was the vision of the leaders of our profession that we as RT’s become further educated and more knowledgeable in the care and monitoring of the critically ill patients. Given that the respiratory therapist is at the bedside around the clock, as previously stated, is well-versed in the intricacies of the cardiopulmonary anatomy, and has a technical expertise that is constantly growing, the adoption of POC lung ultrasound is one more tool that we can add tour toolbox to assist with the enhancement of care that our patients deserve.
Paul Nuccio, MS, RRT, FAARC, is a retired director of pulmonary services at Boston’s Brigham & Women’s Hospital and the Dana-Farber Cancer Institute. He was also recently a faculty member for Boise State University’s Respiratory Care Degree Advancement Program. Paul presently works as a consultant and educator.
- Oba Y, Zaza T. Abandoning daily routine chest radiography in the intensive care unit. Meta-analysis. Radiology 2010;255(2):386-395.
- Bouhemad B, et al. Clinical review: Bedside lung ultrasound in critical care practice. Biomed Central Ltd 2007. http://ccforum.com/content/11/1/205.
- Beckmann U, et al. Incidents relating to the intra-hospital transfer of critically ill patients. An analysis of the reports submitted to the Australian Incident Monitoring Study in Intensive Care. Intensive Care Med 2004;30(8):1579-1585.
- Lavine M. The early clinical x-ray in the United States: patient experiences and public perceptions. J Hist Med Allied Sci. 2012 Oct;67(4):587-625. doi: 10.1093/jhmas/jrr047. Epub 2011 Sep 6. PMID: 21896562.
- Mayo JR Aldrich J, Muller NL. Radiation exposure at Chest CT: a statement of the Fleischner Society. Radiology 2003, 228:15-21.
- Rutala WA, Weber DJ. Disinfection and sterilization in health care facilities: what clinicians need to know. Clin Infect Dis 2004, 39:702-709.
- See KC, et al. Lung ultrasound training: curriculum implementation and learning trajectory among respiratory therapists. Intensive Care Med 2016, 42:63-71.
- Skoczynski S, et al. Lung ultrasound may improve COVID-19 safety protocols. J Thoracic Dis 2021;13(5):2698-2704.
- Barnes TA, et al. Competencies Needed by Graduate Respiratory Therapists in 2015 and Beyond. Respir Care 2010;55(5):601-616.
Respiratory Therapists and Lung Ultrasound