Why PoCUS?

Ultrasound-guidance has been instrumental in changing regional anesthesia from the practice of relatively few experts to a common tool widely used by many anesthesiologists. Ultrasound (US) imaging is now used in virtually all anesthesiology practices in the United States and Canada to guide interventions such as regional anesthesia procedures (both central neuraxial and peripheral nerve blocks) and vascular access. 

Point-of-care applications of ultrasound (PoCUS) relevant to anesthesia practice are in many cases more accurate than traditional imaging modalities and clinical assessment models for a variety of diagnosis. By definition, PoCUS involves a focused or limited exam aimed at answering a well-defined clinical question to guide patient management with the intention of improving patient outcomes. Many view PoCUS today as a 21st century extension of the physical exam performed and interpreted at the bedside by the physician providing patient care. Some of these applications require limited training to become proficient at basic, yet potentially life-saving PoCUS skills.[1,2]  PoCUS for pulmonary assessment of acute respiratory events is superior to chest X-Ray for ruling out pneumothorax[3] and better than fluoroscopy to diagnose hemidiaphragmatic paresis.[4] Lung ultrasound is also an excellent tool to diagnose other lung pathology such as bronchospasm, consolidation, and pulmonary edema.[5]

Focused transthoracic echocardiography (fTTE) is an important tool in the hands of anesthesiologists and critical care physicians to supplement clinical evaluation and optimize cardiopulmonary resuscitation in the perioperative setting.[6,7] Unlike transesophageal echocardiography, fTTE does not require a general anesthetic and therefore can be performed on any patient in the perioperative setting with an exposed chest. Of specific interest to regional anesthesiologists, PoCUS can help diagnose several possible adverse events related to regional anesthesia such as pneumothorax, hemidiaphragmatic paresis, and hemodynamic instability in the setting of spinal/epidural anesthesia.  Other emerging PoCUS applications include: a) airway assessment,[8,9] b) gastric content and aspiration risk evaluation,[10,11] and c) assessment of intracranial pressure.[12]

With the evolving role of the anesthesiologist as a perioperative physician within perioperative surgical home (PSH) initiatives, a number of institutions are starting to incorporate comprehensive US curricula into their residency training,[13,14] with a recent editorial acknowledging the transformative nature of PoCUS for anesthesiologists.[15] Ultrasound has been recommended by the Agency for Healthcare Research and Quality as a key intervention,[16] decreasing the risk of complications and allowing physicians to more quickly determine the cause of life-threatening illness. Despite a rapidly growing interest in PoCUS, especially among junior anesthesiologists and recent graduates, PoCUS has not yet become part of standard curricula of most anesthesia residency programs and is not yet being systematically taught at most large specialty society meetings.  Consequently, the vast majority of currently practicing anesthesiologists have not undergone systematic training in PoCUS.

  

References

  1. Ramsingh D, Rinehart J, Kain Z, Strom S, Canales C, Alexander B, Capatina A, Ma M, Le KV, Cannesson M. Impact assessment of perioperative point-of-care ultrasound training on anesthesiology residents. Anesthesiology 2015. Sep;123(3):670-82.
  2. Skubas NJ. Teaching whole body point-of-care ultrasound: advancing the skills of tomorrow's anesthesiologists. Anesthesiology. 2015 Sep;123(3):499-500.
  3. Monti JD, Younggren B, Blankenship R. Ultrasound detection of pneumothorax with minimally trained sonographers: a preliminary study. J Spec Oper Med 2009;9:43–6.
  4. Cowie B, Kluger R. Evaluation of systolic murmurs using transthoracic echocardiography by anaesthetic trainees. Anaesthesia. 2011 Sept; 66 (9): 785-90.
  5. Zhang et al. Diagnosis of Pneumothorax by Radiography and Ultrasonography: A meta-analysis. CHEST 2011;140:859-866.
  6. Houston, M. Fleet, M. D. Cowan, and N. C. McMillan, “Comparison of ultrasound with fluoroscopy in the assessment of suspected hemidiaphragmatic movement abnormality,”Clinical Radiology, vol. 50, no. 2, pp. 95–98, 1995
  7. Lichtenstein DA, Mezière GA. Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol. Chest. 2008 Jul;134(1):117-25.
  8. Jensen, M.B., Sloth, E., Larsen, K.M., et al. Transthoracic Echocardigraphy for cardiopulmonary monitoring in intensive care. European Journal of Anaesthesiology. 2004 Sep; 21 (9): 700-7.
  9. Bøtker MT, Vang ML, Grøfte T, Sloth E, Frederiksen CA. Routine pre-operative focused ultrasonography by anesthesiologists in patients undergoing urgent surgical procedures. Acta Anaesthesiol Scand. 2014 Aug;58(7):807-14.
  10. Muslu B, Sert H, Kaya A, Demircioglu RI, Gözdemir M, Usta B, Boynukalin KS. Use of sonography for rapid identification of esophageal and tracheal intubations in adult patients. J Ultrasound Med 2011;30:671–6.
  11. Green JS, Tsui BC. Applications of ultrasonography in ENT: airway assessmentand nerve blockade. Anesthesiol Clin. 2010 Sep;28(3):541-53.
  12. Perlas A, Mitsakakis N, Liu L, Cino M, Haldipur N, Davis L, Cubillos J, Chan V. Validation of a mathematical model for ultrasound assessment of gastric volume by gastroscopic examination.  Anesthesia and Analgesia 2013 February; 116(2) 357-363
  13. Van de Putte P, Perlas A. Ultrasound assessment of gastric content and volume.  A systematic review of the literature. British Journal of Anesthesia 2014 July; 113 (1): 12-22.
  14. Rajajee V, Vanaman M, Fletcher JJ, Jacobs TL. Optic nerve ultrasound for the detection of raised intracranial pressure. Neurocritical Care. 2011 Dec: 15(3): 506-15.
  15. Alem, K, Ahn, M. Canesson, Z. Kain. Perioperative medicine and the future of anesthesiology training. ASA Newsletter April 2015. 32-34.
  16. Making Health Care Safer II. January 2015. Agency for Healthcare Research and Quality, Rockville, MD