Introduction

Diagnostic Point-of-Care Ultrasound

Point-of-care ultrasound (POCUS) is defined as the use of ultrasound at the bedside to answer a specific diagnostic question or guide performance of an invasive procedure. POCUS guidance for bedside procedures (‘procedural POCUS’) has become standard of care for many procedures,^1-3 and diagnostic POCUS use can improve accuracy and clinical decision-making which has been endorsed by the Society of Hospital Medicine and the American College of Phsycians.^4-9

There is extensive literature to support the use of diagnostic POCUS to supplement the physical exam. Internal medicine residents were 6 times more sensitive at detecting high central venous pressure (CVP)  with a pocket US than with the standard neck vein exam.¹⁰ First year medical students are better at diagnosing heart failure with a pocket US than cardiology fellows using the standard physical exam.¹¹ POCUS assessment for DVT has shown 99% agreement with formal radiology US while reducing time to diagnosis by 2 hours.¹²  Doctors at the front lines can now make more accurate bedside assessments which expedite appropriate care of patients. Given the totality of the literature, the cardiology and radiology national societies have endorsed diagnostic POCUS.^13,14

Point-of-care US is not meant to replace formal diagnostic US. Instead training focuses on accurately assessing a small number of well-defined and clinically significant pathologies that have been shown to be accurate and reproducible by general internists. For instance cardiac POCUS in hospital medicine is restricted to recognizing reduced ejection fraction (EF), pericardial effusions, right heart strain, and estimating CVP. Diagnosis of other conditions like valvular disease or diastolic dysfunction is outside the domain of POCUS.

Course Objectives

Most POCUS curriculums are taught by emergency or critical care physicians, but this curriculum is specifically tailored to the hospital medicine patient population. There are many POCUS potential applications, but we have been broken down the highest yield skills by organ system, so you can select the areas most relevant to your practice. Upon completion of each video series, learners will be able to

• • Understand when to use point-of-care ultrasound
  • Recognize the limitations of POCUS sensitivity and specificity
  • Become competent in image interpretation
  • Appropriately integrate ultrasound into clinical management
  • Encourage a life-long learning of POCUS and quality improvement.

Certification vs Credentialing

Credentialing (privileging) for diagnostic point-of-care ultrasound (POCUS) is determined by each individual hospital. There is no national credentialling program nor standards for internal medicine. POCUS falls into a nebulous zone of hospital privileging. If POCUS is considered an extension of the physical exam, then any hospitalist credentialed to perform a history and physical can also perform POCUS in that hospital. If POCUS is considered to be  more invasive or risky, like a procedure, then additional privileging requirements may be needed. The Society of Hospital Medicine POCUS guidelines leave it up to each individual institution to determine their preference.¹⁵

Certification of Competency

Certification refers to a process that ensures a doctor is competent to perform POCUS independently with out supervision. Documentation of certification can aid the credentialing process above. Certification can occur externally through organizations like Society of Hospital Medicine. External certification process often cost > $2,000. You can also get certified internally at your own institution via your Director of POCUS. All certification pathways should share similar criteria:

1. 1. Completion of a series of videos or lectures to provide a knowledge base that emphasizes
      • Fundamentals
      • Image interpretation
      • Clinical case integration
   2. Completion of hands on training that emphasizes
      • Image acquisition
   3. Completion of an image portfolio that emphasizes
      • Practice optimizing image acquisition
      • Verify correct image interpretation
      • Practice clinical case integration on real patients
   4. Summative assessment that ensures competency of the above domains

The field of emergency medicine has clearly defined their POCUS applications and the amount of training required for competency.¹⁶ Internal medicine is in early of stages of this process, though there are discrepancies among some of the early recommendations.^17-19 I recommend the following applications for hospital medicine based my personal experience which mirrors the curriculums from the American College of Physicians Foundational Skills Course and the Society of Hospital Medicine Certificate of Completion.

Central Venous Pressure Exam (10 patients)

• • • Jugular venous pressure
    • Inferior vena cava with CVP 0-5mmHg
    • Inferior vena cava with CVP 5-10mmHg
    • Inferior vena cava with CVP 10-20

Pulmonary (10 patients)

• • • A lines
    • B lines
    • Pleural effusion
    • Consolidation
    • Lung sliding (including M mode)
    • Lack of lung sliding (including M mode)

Cardiac (25 patients)

• • • Normal Heart
      • Parasternal long axis
      • Parasternal short axis
      • Apical 4 chamber
      • Subxiphoid
    • At least 1 of all of the following patholgoies
      • Hyperdynamic EF > 65%
      • Moderately reduced EF 30%-50%
      • Severely reduced EF < 30%
      • Pericardial effusion
      • Right ventricular strain

Abdomen (10 patients)

• • • Normal FAST exam (3 views)
    • Small volume ascites
    • Large volume ascites
    • Normal kidneys (short and long axis)
    • Hydronephrosis
    • Bladder distension

Deep Vein Thrombosis (10 patients)

• • • Normal lower extremity DVT Exam
      • Saphenous vein
      • Deep formal vein branch
      • Popliteal vein
    • Abnormal DVT exam with non-compressible thrombus

Musculoskeletal (10 patients)

• • • Normal subcutaneous tissue
    • Normal suprapatellar bursa
    • Edema
    • Abscess
    • Large joint effusion

Prior to Certification of Competency

A critical step in POCUS skill development is practicing on real patients during the image portfolio phase. It takes months, if not years, of deliberate practice to become competent at POCUS. Prior to competency during this pre-entrustment phase, you should not make major management decisions based on your POCUS exams.

You are not sensitive enough to rule out pathology. If you are considering canceling an echo because the heart “looks ok,” you should stick with your original instinct of ordering a formal echo to confirm your assessment. You exams lack the specificity to make high stakes decisions. If you think you see a deep vein thrombosis (DVT), instead of immediately starting anticoagulation, you should expedite formal  DVT ultrasound to confirm your findings. The power of POCUS in this early phase is recognizing potentially life threatening disease like tamponade and then expediting formal cardiology evaluation. 

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References