Introduction

Many of the technological advancements adopted by our specialty such as the pulse oximeter, capnography, brain function monitoring, and video laryngoscopy have revolutionized patient care and safety and have been adopted by other clinicians involved in acute care. In the recent past, there was heated debate, including in this Newsletter,¹ regarding the impact of ultrasound in increasing patient safety for the placement of central lines and nerve blocks. Similarly, we believe that Portable Point of Care Ultrasound (PPOCUS) which involves the use of handheld, portable, affordable, easy-to-use ultrasound devices to perform point of care ultrasound (POCUS) is an emerging technology that has the potential to improve perioperative patient safety.

PPOCUS is undergoing a revolution similar to what computing technology experienced in the 20th century, an acceleration in the development of portable, efficient, and affordable systems. Ultrasound technology has evolved to the point that portable ultrasound devices can now fit seamlessly in a clinician’s back scrub pocket (Figure 1) at a price point as low as $2000 USD. Furthermore, the imaging capabilities far exceed many of the best ultrasound machines of decades ago.

The revolution in PPOCUS is facilitated not just by the portable nature of the hardware of current pocket-sized ultrasound devices, but also by the software available to support the user and its adoption. Many of the conventional ultrasound devices require rudimentary methods such as USB cables to download and store images. However, the newer PPOCUS devices are now able to directly upload acquired images to the cloud via WiFi or cellular network. This new technological capability can seamlessly be integrated into the Picture and Archiving Communication System (PACS) and patient’s electronic medical record system. PPOCUS studies are able to be de-identified with a single click² in order to maintain patient privacy and confidentiality. However, specific institutional guidelines to protect patient privacy regarding storing this information is variable throughout the US. Nevertheless, this easy integration that meets HIPAA-compliant standards allows for immediate collaboration with other health care providers as well as providing new real-time opportunities for quality assurance of the studies obtained. In addition, some of the handheld devices have novel teleguidance technologies that allow ultrasound experts to guide novice ultrasound users through an ultrasound exam remotely and allow for live image acquisition, interpretation, and feedback.³ Artificial intelligence is expected to further facilitate image acquisition and interpretation, providing real-time clinically relevant capabilities such as the determination of left ventricular function and the presence of pulmonary edema.

Indications and Limitations of PPOCUS

The increased accessibility of PPOCUS devices has allowed for its meaningful use in a variety of patient care situations where perioperative ultrasound may impact patient outcomes.⁴ In our practice at the Massachusetts General Hospital (MGH), we have adopted handheld ultrasound devices within all perioperative domains to make time-sensitive diagnoses, perform serial assessments, and guide important management decisions. Table 1 shows the many indications for the perioperative use of PPOCUS by anesthesia professionals. Table 2 compares PPOCUS with POCUS which highlights many of the advantages and limitations of this technology.

Table 1: Emerging Indications for PPOCUS Use by the Anesthesia Professional

Environments with significant time constraints, production pressure, and limited space (i.e., preoperative bay, for instance after a regional block, preoperative evaluation clinic, OR, OB, PACU, ICU, and floor)

Qualitative assessment using a focused binary decision-making approach sufficient to answer the clinical question (i.e., Is there severely reduced LV function? Yes or No)

Facilitate preoperative evaluation when a preoperative echo is desired but has not been obtained to avoid significant case delays and cancellations associated with obtaining a formal echo study

Confirm clinically significant physical exam findings (i.e., undocumented murmur consistent with aortic stenosis)

Ultrasound guidance of procedures such as IV access, CVC and arterial line placement, regional blocks, thoracentesis, paracentesis, cricothyroidotomy

To perform emergent lifesaving procedures in nonideal conditions (e.g., placing arterial line under the drapes in a crashing patient, on a hospital floor in a patient’s room, or in a non-operating room procedural area)

Differentiating between various types of shock

Quickly ruling out life-threatening pathology (i.e., tamponade, pneumothorax, and pulmonary embolism) in critically unstable patients

Verifying endotracheal vs. esophageal intubation during cardiac arrest when capnography may not be a reliable indicator of endotracheal intubation13

Differentiating PEA vs. pseudo-PEA during cardiopulmonary arrest

Optimizing left and right heart function while avoiding invasive procedures and monitors (i.e., PA line, TEE) and their associated complications

Rapid evaluation and assessment of volume status in critically unstable patients14-16

Assess gastric volume to determine aspiration risk

Evaluation for pulmonary edema or pneumothorax to facilitate optimization in the perioperative period

Table 2: Summary of the similarities and differences of POCUS with portable ultrasound devices (PPOCUS) compared to conventional ultrasound platforms

Characteristic	PPOCUS	Conventional US
Cost	$2,000 to $12,500	$30k to 100k+
Portability/space requirements	Extreme portability/Devices can fit in a scrub pocket and many weigh less than a pound	Not always portable/Devices may weigh up to hundreds of pounds
Bootup time	Seconds	Up to minutes
Time to successful deployment and use	Quick, given extreme portability	Slow, given labor intensive to mobilize
Electrical outlet requirement	No	Some
Quality of imaging	Good enough for binary decision-making	Generally higher quality imaging
EKG synchronization capability	No	Yes
Ability to use in situations where space is limited	Yes	No
Transesophageal echocardiography capability	Not presently	Yes
Potential for disruption to ongoing critical care support (i.e., chest compressions)	Low	High
Wireless and/or 3G integration with the PACS	Some	Some
Allows for quick de-identification of studies to facilitate external collaboration	Yes	No
Teleguidance and AI capability to facilitate data acquisition, interpretation, and collaboration	Many	Limited
Knobology (or the functionality of controls on ultrasound device)	Limited, which may facilitate use by novice users	Extensive, which may complicate use
Ability to use M-mode and color doppler	Yes	Yes
Ability to use PWD, CWD, and TDI	No	Yes
Integration with EMR, PACS	Many	Most

Abbreviatons: Artificial Intelligence (AI), Continuous Wave Doppler (CWD), Electronic Medical Record (EMR), Picture Archiving and Communication System (PACS), Pulse Wave Doppler (PWD), Tissue Doppler Imaging (TDI), ultrasound (US)

Facilitating Adoption and Competency for PPOCUS

Widespread adoption of a new technology like ultrasound can be daunting due to lack of familiarity, formal training, or a conditioned reliance on formal services staffed by cardiologists and cardiac anesthesiologists. Surveys of anesthesiologists have revealed the fear of missed diagnoses and the lack of formal training or certification as important barriers to the adoption of focused TTE in their practice.⁵ Understandably there are many who may be concerned about the medical/legal ramifications of “nonexperts” performing PPOCUS. This is a valid concern for both users and hospital administrators. However, it is reassuring that the known malpractice lawsuits to date have related not to the misdiagnosis and misinterpretation of POCUS, but rather to the entire lack or delay in the use of POCUS.^6–8

At MGH, PPOCUS was initially employed by ultrasound enthusiasts who were looking to be self-reliant in evaluating and rescuing their own patients before things “spiraled out of control.” Anesthesia professionals who were PPOCUS enthusiasts increasingly began to respond to “anesthesia stats” and emergencies in a variety of clinical arenas in which we practice, and PPOCUS demonstrated its utility to others by answering clinically important questions in a rapid time frame. PPOCUS was shown to be instrumental in the rapid assessments of acute conditions, allowing patients to be rescued even before our formal rescue echo service could be fully mobilized, which helped to facilitate its adoption in the department. Further support for PPOCUS was achieved in our department after it demonstrated its utility in avoiding unnecessary transfer of patients to higher levels of care such as the ICU, resulting in better utilization of limited hospital resources with the rapid identification of reversible causes of deterioration gleaned by clinicians using it.

One of the major advantages of PPOCUS is that it can be readily used by all, without a significant amount of training. Prior studies suggest that physicians with limited prior ultrasonographic experience can gain proficiency in focused ultrasound with limited training, such as a 1-day workshop and as few as 20 practice scans.^9,10 Of note, the American College of Chest Physicians (ACCP) requires 20 TTE studies to earn the certificate of completion for POCUS. The American College of Emergency Physicians (ACEP) requires a minimum of 25 studies per imaging application. Similarly, the Society of Point of Care Ultrasound recommends a minimum of 25 studies for certification in POCUS. Similar competencies might be developed for PPOCUS.

Recommendations and strategies to facilitate PPOCUS Use

Our PPOCUS philosophy is that “anyone can do it”—not just cardiac anesthesiologists and cardiologists. Our educational strategy has been to target clinicians that are interested in implementing this technology in their daily practice and subsequently champion its use throughout the department. PPOCUS is ideal for ultrasound education because the “activation energy” required to teach novice users ultrasound skills, and for novice users to practice those skills, is significantly reduced due to the extreme portability, affordability, and ease of use.

At the MGH, we have found that PPOCUS has helped to facilitate ultrasound training of over 40 anesthesia professionals over the last 6 months without requiring significant departmental support and a formalized structured training program. While we have formal training modules available, we do not initially require their use so as to avoid dissuading the learners before they’ve had enough hands-on training with an expert to develop some self-confidence and enthusiasm applying the new skill in clinical practice.
Enthusiastic novice users often find their own interesting resources (i.e., YouTube, podcasts, websites, etc.) to facilitate their self-learning, independently practice on our high fidelity TTE simulator, and perform a minimum of 5–10 studies one-on-one with an expert user until they are able to adequately perform a limited study on their own. Most achieve competence in obtaining the standard cardiopulmonary views (parasternal long axis, parasternal short axis, apical four-chamber view, subcostal four-chamber view, IVC view, and lung ultrasound) within 20 studies that are performed in a short period of time (within a month). We attempt to facilitate access to portable ultrasound devices so that learners can sustain the momentum necessary to achieve rapid growth of their POCUS skills. Interestingly, many of the clinicians most receptive to learning PPOCUS are early in their anesthesia training (i.e., CA-1). We hope that the junior anesthesia trainees will go on to train both the current and the next generation of anesthesia professionals so that our entire department will become experts in POCUS.

Conclusion

The incorporation of PPOCUS into perioperative care seems inevitable given its potential to enhance patient safety. It is therefore important to consider the optimal means of incorporating this technology into clinical practice and ensuring that it is used correctly by building appropriate training curriculums. For example, early targets for implementation might include integration into simulation training, emergency manuals, residency training programs, and perioperative domains where feasible. Our specialty, which has been a pioneer in patient safety should promote proficiency in PPOCUS similar to the field of emergency medicine over a decade ago.^11,12 Anesthesia professionals should embrace and innovate its use as a new paradigm for patient safety and education in perioperative medicine.

 

Dr. Lindsay is a resident in the Department of Anesthesia, Critical Care, and Pain Medicine at the Massachusetts General Hospital, Boston, MA.

Dr. Gibson is a resident in the Department of Anesthesia, Critical Care, and Pain Medicine at the Massachusetts General Hospital, Boston, MA.

Dr. Bittner is an associate professor in the Department of Anesthesia, Critical Care and Pain Medicine at the Massachusetts General Hospital, Boston, MA. He is an associate editor of the APSF Newsletter.

Dr. Chang is the assistant program director of the Critical Care Anesthesiology Fellowship and a member of the faculty in the Department of Anesthesia, Critical Care and Pain Medicine at the Massachusetts General Hospital, Boston, MA.

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The authors do not have any disclosures.

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