POCUS in perioperative medicine: a North American perspective

Point-of-care ultrasound in pediatric anesthesiology: considerations for training and credentialing

PURPOSE OF REVIEW

To discuss considerations surrounding the use of point-of-care ultrasound (POCUS) in pediatric anesthesiology.

RECENT FINDINGS

POCUS is an indispensable tool in various medical specialties, including pediatric anesthesiology. Credentialing for POCUS should be considered to ensure that practitioners are able to acquire images, interpret them correctly, and use ultrasound to guide procedures safely and effectively. In the absence of formal guidelines for anesthesiology, current practice and oversight varies by institution. In this review, we will explore the significance of POCUS in pediatric anesthesiology, discuss credentialing, and compare the specific requirements and challenges currently associated with using POCUS in pediatric anesthesia.

SUMMARY

Point-of-care ultrasound is being utilized by the pediatric anesthesiologist and has the potential to improve patient assessment, procedure guidance, and decision-making. Guidelines increase standardization and quality assurance procedures help maintain high-quality data. Credentialing standards for POCUS in pediatric anesthesiology are essential to ensure that practitioners have the necessary skills and knowledge to use this technology effectively and safely. Currently, there are no national pediatric POCUS guidelines to base credentialing processes on for pediatric anesthesia practices. Further work directed at establishing pediatric-specific curriculum goals and competency standards are needed to train current and future pediatric anesthesia providers and increase overall acceptance of POCUS use.

Trends in Point of Care Ultrasound Familiarity Among Undergraduate Medical Clerkship Educators

OBJECTIVES

Despite growing use of point of care ultrasound (POCUS), there remains a paucity of data about familiarity with POCUS among educators who dictate curricular content in undergraduate medical education. This paper aims to longitudinally characterize the level of comfort and frequency of POCUS use among faculty involved in undergraduate clerkship education.

METHODS

A web-based cross-sectional survey assessing comfort, frequency of use, and awareness of indications for POCUS among faculty involved in Internal Medicine, Family Medicine, and Surgery undergraduate clerkship education in a single urban academic medical center in 2016 and again in 2022.

RESULTS

A total of 45 responses from 2016 and 30 responses from 2022 are included. The percentage of faculty "not comfortable" with performing POCUS decreased from 78% to 46%, although the overall change in comfort was not statistically significant. Comfort interpreting POCUS images, frequency of POCUS use, and familiarity with the clinical applications of POCUS all improved. Faculty identified multiple barriers to more frequent POCUS use.

CONCLUSIONS

Over a six-year period at one urban, academic medical center, comfort with POCUS and frequency of use have increased slightly but remain low among core faculty responsible for clerkship education. There are still large gaps in knowledge and very few faculty regularly use POCUS, which can be attributed to multiple different barriers.

Anesthesia Considerations for Placenta Accreta Spectrum

Anesthesiologists are critical members of the multidisciplinary team managing patients with suspected placenta accreta spectrum (PAS). Preoperatively, anesthesiologists provide predelivery consultation for patients with suspected PAS where anesthetic modality and invasive monitor placement is discussed. Additionally, anesthesiologists carefully assess patient and surgical risk factors to choose an anesthetic plan and to prepare for massive intraoperative hemorrhage. Postoperatively, the obstetric anesthesiologist hold unique skills to assist with postoperative pain management for cesarean hysterectomy. We review the unique aspects of peripartum care for patients with PAS who undergo cesarean hysterectomy and explain why these responsibilities are critical for achieving successful outcomes for patients with PAS. KEY POINTS: · Anesthesiologists are critical members of the multidisciplinary team planning for patients with suspected placenta accreta spectrum.. · Intraoperative preparation for massive hemorrhage is a key component of anesthetic care for patients with PAS.. · Obstetric anesthesiologists have a unique skill set to manage postpartum pain and postoperative disposition for patients with PAS who undergo cesarean hysterectomy..

Current role and future perspectives of artificial intelligence in echocardiography

Echocardiography is an essential tool in diagnostic cardiology and is fundamental to clinical care. Artificial intelligence (AI) can help health care providers serving as a valuable diagnostic tool for physicians in the field of echocardiography specially on the automation of measurements and interpretation of results. In addition, it can help expand the capabilities of research and discover alternative pathways in medical management specially on prognostication. In this review article, we describe the current role and future perspectives of AI in echocardiography.

Three-Dimensional Imaging of Commonly Performed Peripheral Blocks: Using a Handheld Point-of-Care Ultrasound System

Background

Handheld ultrasound devices have become popular among clinicians due to their affordability and compatibility with tablets and smartphones. Several handheld ultrasound devices have the capability to construct three-dimensional (3D) images using a traditional two-dimensional (2D) ultrasound transducer.

Objectives

The current study aimed to construct 3D images of common peripheral nerve and fascial plane blocks using a handheld ultrasound device with a 2D ultrasound probe.

Methods

A total of 10 patients who were scheduled to receive ultrasound-guided peripheral nerve blocks for outpatient surgery and classified as the American Society of Anesthesiologists physical status I or II with a body mass index of ≤ 30 kg/m² were included in the study. Patients who presented with anatomical variations during the initial ultrasound scanning were excluded.

Results

This study successfully constructed 3D images of 10 peripheral nerve blocks. The average time to complete each 3D scan was less than 5 seconds per attempt, with fascial plane blocks requiring twice the amount of time to complete. All the nerve blocks provided effective postoperative analgesia without complications. The 3D images were successfully captured in all patients.

Conclusions

The 3D images provide clinicians with valuable information on the anatomical boundaries of the injectate that can further direct needle direction and placement of local anesthetic to achieve visual confidence of anesthetic spread.

Perioperative Venous Excess Ultrasound Score (VExUS) to Guide Decongestion in a Dilated Cardiomyopathy Patient Presenting for Urgent Surgery

Venous excess ultrasound score (VExUS) is a recently described ultrasound-based scoring system that quantifies systemic congestion using Doppler flow indices of the hepatic and portal vein in addition to inferior vena cava assessment. There are many potential and emerging applications of this modality. We discuss the case of a severely congested heart failure patient presenting for urgent non-cardiac surgery where VExUS parameters were used to monitor and guide his decongestive therapy postoperatively.

Pre-operative transthoracic echocardiography in ambulatory surgery-A cross-sectional study

BACKGROUND

Cardiac disease and aberrations in central volume status are risk factors for perioperative complications, and should be identified prior to surgery. This study investigated the benefit of transthoracic echocardiography (TTE) for pre-operative identification of cardiac disease and hypovolemia in ambulatory surgery.

METHODS

Ninety-six patients, with a mean age of 63.5 ± 12.2 years and body mass index of 27.0 ± 4.3 kg/m² , scheduled for ambulatory surgery (breast, thyroid, and minor gastrointestinal), were consecutively enrolled in this prospective observational study. Pre-operative comprehensive TTE was performed in order to assess heart failure (HF), asymptomatic left ventricular dysfunction, valvular disease, and aberrations in central volume status.

RESULTS

Pre-operative TTE identified a total of 28 cases of HF, 13 cases of HF with reduced or moderately reduced, ejection fraction (EF), and 15 cases of HF with preserved EF. Furthermore, 46 cases of asymptomatic left ventricular (LV) dysfunction were identified. 44/96 patients were hypovolemic, 16 of whom in severe hypovolemia. Seven cases of previously unknown obstructive valvular or myocardial disease and six cases of right ventricular systolic dysfunction were identified. A total of 24% (23/96) were classified as potential critical hemodynamic findings. The number needed (NNT) to treat for pre-operative TTE in order to find one critical finding was 4.2.

CONCLUSION

In this ambulatory surgical cohort, a high prevalence of pre-operative LV dysfunction and aberrations in volume status was observed. The results demonstrate that pre-operative TTE contributed valuable hemodynamic information. The standard pre-operative assessment for this cohort might need to be revised.

Artificial Intelligence in Echocardiography for Anesthesiologists

Echocardiography is a unique diagnostic tool for intraoperative monitoring and assessment of patients with cardiovascular diseases. However, there are high levels of interoperator variations in echocardiography interpretations that could lead to inaccurate diagnosis and incorrect treatment. Furthermore, anesthesiologists are faced with the additional challenge to interpret echocardiography and make decisions in a limited timeframe from these complex data. The need for an automated, less operator-dependent process that enhances speed and accuracy of echocardiography analysis is crucial for anesthesiologists. Artificial intelligence is playing an increasingly important role in the medical field and could help anesthesiologists analyze complex echocardiographic data while adding increased accuracy and consistency to interpretation. This review aims to summarize practical use of artificial intelligence in echocardiography and discusses potential limitations and challenges in the future for anesthesiologists.

Novel 4W (When-Where-What-What) Approach of Training Point-of-Care Ultrasound (POCUS) Application in Resuscitation With High-Fidelity Simulator

Aim

Point-of-care ultrasound (POCUS) is a valuable tool in anesthesiology used for evaluating and managing cardiopulmonary pathology. Implications of this modality are extensive. Seamless integration into advanced cardiac life support (ACLS) has potential to improve resuscitation outcomes, and there is growing impetus for its implementation during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. However, it remains underutilized largely due to limited training. We use high-fidelity simulation and a novel 4W approach (when to apply POCUS, where to place the ultrasound probe, what images mean, what to do next) to incorporate this technique into resuscitation training. This study aims to evaluate the efficacy of a novel 4W POCUS approach for training anesthesiology residents in the setting of resuscitation.

Methods

Our approach teaches learners when and where to implement POCUS, how to interpret their findings, and how to apply these findings in a clinical setting. Learners apply this method in high-fidelity simulation to diagnose and treat cardiopulmonary pathologies. Assessments were administered before and after training to evaluate efficacy.

Results

Post-test improvements were appreciated across all residency classes (n = 23), with achieved significance of P < 0.001 in the first-year clinical anesthesia class (CA-1) and P = 0.02 in the second-year clinical anesthesia class (CA-2). Performance was further subdivided into five categories: resuscitation integration, lung ultrasound, transthoracic echo, disease recognition, and treatment. Post-test scores also improved in each category, with lung ultrasound being the most significant improvement (P = 0.04).

Conclusions

Our initial data demonstrate the effectiveness of this approach to POCUS training. Performance is improved and learners are more likely to use POCUS in the future. The application of this method to larger sample sizes is an appropriate next step to demonstrate its utility.

Focus on PoCUS or hocus pocus? Integrating point-of-care ultrasound into residency and clinical practice

Point-of care ultrasound (PoCUS) is a new clinical diagnostic paradigm that plays an instrumental role in the ongoing anesthesiologist’s evolving role towards a perioperative physician. Currently, there are few approved curricula that incorporate a PoCUS program into anesthesia residency. This article examines relevant PoCUS applications for anesthesiologists, presents an overview of existing international guidelines for education and training, and reflects on the need for specialty-wide standards. We present a possible framework, that could offer a first move towards a structured PoCUS pathway for Belgian anesthesia residents and facilitate its incorporation into national anesthesia practice.

Point-of-Care Ultrasound Before and After Transfemoral Transcatheter Aortic Valve Implantation

Objective

Surgical aortic valve replacement requires a comprehensive transoesophageal echocardiography (TEE) assessment before and after the intervention by cardiac anaesthesiologists. For patients undergoing transfemoral transcatheter aortic valve implantation (TF-TAVI), TEE is not routinely used. We started using transthoracic echocardiography (TTE) as a diagnostic and monitoring modality during TF-TAVI procedures. The aim of this study is to examine the usefulness of TTE before and after TF-TAVI. We hypothesised that TTE can serve as a screening tool in TF-TAVI patients and help rule out significant paravalvular leaks (PVLs), and serve as a monitoring tool.

Methods

A retrospective, observational study of 24 patients who underwent TF-TAVI with perioperative TTE over a 3-month period was conducted. Intraoperatively, two TTE examinations were performed. The first was a baseline pre-procedural TTE examination after anaesthetic induction, and the second was performed after TAVI valve implantation. Both pre- and post-procedural examinations included five focused TTE views. PVLs were graded as none, non-significant (trace or mild) or significant (moderate or severe).

Results

The average age and median body mass index of the patients were 82 years and 28.5 kg m⁻², respectively. The average time recorded for the pre- and post-TAVI TTE examinations were approximately 4 and 5.5 min, respectively. Non-significant PVL was detected in 6 (25%) patients, and no leak was detected in 18 (75%) patients.

Conclusion

A focused TTE examination was found to be a useful adjunct during TF-TAVI for a cardiac anaesthesiologist in the absence of TEE, and useful in ruling out significant PVLs.

Perioperative Point-of-Care Ultrasound

This clinical focus review targets all anesthesiologists and seeks to highlight the following aspects of perioperative point-of-care ultrasound: clinical utility, technology advancements, training/certification, education, reporting/billing, and limitations.

Point-of-Care Ultrasound for Obstructive Sleep Apnea Screening: Are We There Yet? A Systematic Review and Meta-analysis

BACKGROUND

Perioperative diagnosis of obstructive sleep apnea (OSA) has important resource implications as screening questionnaires are overly sensitive, and sleep studies are expensive and time-consuming. Ultrasound (US) is a portable, noninvasive tool potentially useful for airway evaluation and OSA screening in the perioperative period. The objective of this systematic review was to evaluate the correlation of surface US with OSA diagnosis and to determine whether a point-of-care ultrasound (PoCUS) for OSA screening may help with improved screening in perioperative period.

METHODS

A search of all electronic databases including Medline, Embase, and Cochrane Database of Systematic Reviews was conducted from database inception to September 2017. Inclusion criteria were observational cohort studies and randomized controlled trials of known or suspected OSA patients undergoing surface US assessment. Article screening, data extraction, and summarization were conducted by 2 independent reviewers with ability to resolve conflict with supervising authors. Diagnostic properties and association between US parameters (index test) and OSA diagnosis using sleep study (reference standard) were evaluated. The US parameters were divided into airway and nonairway parameters. A random-effects meta-analysis was planned, wherever applicable.

RESULTS

Of the initial 3865 screened articles, 21 studies (7 airway and 14 nonairway) evaluating 3339 patients were included. Majority of studies were conducted in the general population (49%), respirology (23%), and sleep clinics (12%). No study evaluated the use of US for OSA in perioperative setting. Majority of included studies had low risk of bias for reference standard and flow and timing. Airway US parameters having moderate-good correlation with moderate-severe OSA were distance between lingual arteries (DLAs > 30 mm; sensitivity, 0.67; specificity, 0.59; 1 study/66 patients); mean resting tongue thickness (>60 mm; sensitivity, 0.85; specificity, 0.59; 1 study/66 patients); tongue base thickness during Muller maneuver (MM; sensitivity, 0.59; specificity, 0.78; 1 study/66 patients); and a combination of neck circumference and retropalatal (RP) diameter shortening during MM (sensitivity, 1.0; specificity, 0.65; 1 study/104 patients). Nonairway US parameters having a low-moderate correlation with moderate-severe OSA were carotid intimal thickness (pooled correlation coefficient, 0.444; 95% confidence interval [CI], 0.320-0.553; P value = .000, 8 studies/727 patients) and plaque presence (sensitivity, 0.24-0.75; specificity, 0.13-1.0; 4 studies/1183 patients).

CONCLUSIONS

We found that a number of airway and nonairway parameters were identified with moderate to good correlation with OSA diagnosis in the general population. In future studies, it remains to be seen whether PoCUS screening for a combination of these parameters can address the pitfalls of OSA screening questionnaires.

Learning curve of ultrasound measurement of subglottic diameter for endotracheal tube selection in pediatric patients

BACKGROUND

Endotracheal tube size can be predicted according to ultrasound measurement of subglottic airway diameter. The learning curve for this method is not yet established. The aim was to evaluate the learning curve of anesthesiology residents in ultrasound measurement of subglottic airway diameter for prediction of endotracheal tube size using cumulative sum analysis.

METHODS

Sixteen anesthesiology residents measured transverse subglottic airway diameter in children undergoing general anesthesia with cuffed endotracheal intubation. Each resident performed 30 ultrasound examinations. Primary outcome was the successful prediction of endotracheal tube size according to ultrasound measurement. Cumulative sum analysis was performed with acceptable and unacceptable failure rates set as 20 and 40%, respectively.

RESULTS

Ten out of 16 residents (62.5%) were deemed successful as they were able to pass lower decision boundary, whereas six residents' CUSUM scores were between the decisions lines deeming them indeterminate. The overall success rate for determining the correct endotracheal tube size was 77.5%. Median number of attempts to cross lower decision boundary was 29 with minimum of 18 and maximum of 29 attempts among successful residents.

CONCLUSION

Learning curves constructed with cumulative sum analysis in this study showed that only 62.5% of residents were able to correctly predict cuffed endotracheal tube size with 80% success rate. Considerable variability in achieving competency necessitates objective follow-up of individual improvement.

Current concepts of perioperative monitoring in high-risk surgical patients: a review

A substantial number of patients are at high-risk of intra- or post-operative complications or both. Most perioperative deaths are represented by patients who present insufficient physiological reserve to meet the demands of major surgery. Recognition and management of critical high-risk surgical patients require dedicated and effective teams, capable of preventing, recognize, start treatment with adequate support in time to refer patients to the satisfactory ICU level provision. The main task for health-care planners and managers is to identify and reduce this severe risk and to encourage patient’s safety practices. Inadequate tissue perfusion and decreased cellular oxygenation due to hypovolemia, heart dysfunction, reduced cardiovascular reserve, and concomitant diseases are the most common causes of perioperative complications. Hemodynamic, respiratory and careful sequential monitoring have become essential aspects of the clinical practice both for surgeons and intensivists. New monitoring techniques have changed significantly over the past few years and are now able to rapidly identify shock states earlier, define the etiology, and monitor the response to different therapies. Many of these techniques are now minimally invasive or non-invasive. Advanced hemodynamic and respiratory monitoring combines invasive, non-invasive monitoring skills. Non-invasive ultrasound has emerged during the last years as an essential operative and perioperative evaluation tool, and its use is now rapidly growing. Perioperative management guided by appropriate sequential clinical evaluation combined with respiratory and hemodynamic monitoring is an established tool to help clinicians to identify those patients at higher risk in the attempt to reduce the complications rate and potentially improve patient outcomes. This review aims to provide an update of currently available standard concepts and evolving technologies of the various respiratory and hemodynamic monitoring systems for the high-risk surgical patients, highlighting their potential usefulness when integrated with careful clinical evaluation.