讲座摘要
ICU中的超声检查   General ultrasound in ICU
E Maury
   讲座课件    
Address correspondence to
  Pr E Maury
  Réanimation Médicale
  Hôpital Saint Antoine
  Paris , France
  E-mail: Eric.maury@sat.aphp.fr
   
Abstract
  Ultrasonic examination is actually considered as a direct prolongation of clinical examination.
  This non invasive imaging procedure is safe, relatively inexpensive, reproducible and can be performed at the bedside.
  Ultrasonographic assessment is actually performed by specialists in gastro enterology; obstetrics, pulmonology, rheumatology.
  Intensivists actually use echocardiography in a more and more extended manner.
  Echocardiography in the ICU environment provides a comprehensive assessment of circulatory function [1-3].
  Recent studies performed in ICU suggest that non cardiologist physician without previous knowledge in ultrasound can become competent in the assessment of these parameters after a limited focused training [4, 5].
   
  Whereas non cardiac echography (ie general ultrasonography) is frequently performed in ICU patients, its appropriation by intensivists has not been largely suggested.
  Although several studies highlight the interest of ultrasound in diagnostic and therapeutic procedures and the great simplicity of this exam [6-10], the feasibility of focused abdominal, renal and venous ultrasound assessment by intensivists has not been intensively studied [11].
  This is surprising since most of the questions asked about a critically ill patients and which can be answered using ultrasonography are solved using a very easy to perform and to learn ultrasound semiology.
  These questions are related to the presence or absence: of pleural effusion, abdominal effusion, bladder distension, obstructive uropathy, deep venous thrombosis…and their response are binary (yes or no).
  As a matter of fact, several questions (is there or not a pleural or an abdominal effusion) are very easy to answer.
  Doelken considers that the basic skill required to detect a pleural effusion could be acquired in minutes [6].
  Whereas critically ill patients require prompt and efficacious care, it is sometimes difficult to have a sonographer immediately available on a 24 hours basis.
  Ultrasonography performed by intensivists could significantly spare time allowing a more prompt and accurate care.
   
  Recent studies suggest that following focused training, naïves physicians could become competent in general ultrasound.
  This type of training combines acquisition of ultrasonographics views (of normal and pathological situations) and demonstration of examination of real patients tutored by a confirmed imaging physician rather than theoretical consideration.
  This relatively short format of training, mainly oriented towards practical aspects of US has already demonstrated to be efficient in the teaching of echocardiography to residents in intensive care [4].
  This training allows becoming competent in the assessment of qualitative rather than quantitative measurement.
  This type of assessment is in fact a binary assessment providing three answers: yes, no, I don’t know.
  In case of inability to answer or for more complicated questions, radiologists should be solicited or tomodensitometry performed.
   
  It is of interest to note that despite the fact that training program delivered is limited, it covers more than 85% of the situations in which ultrasonography is deemed to be of interest in critically ill patients.
  This is in keeping with the assertion that most of the time for critically ill patients, ultrasonography is used to answer to basics questions [6, 7].
   
  Ultrasound can also be used in numerous other situations.
  It has previously been demonstrated that for very basic questions which could be solved by ultrasonography (correct insertion of naso gastric tube or of central venous line), intensivists naives in ultrasonography could become competent to answer to these questions after a focused training of only 2 hours [15, 16].
   
  Some limitation to this point of view must however be emphasised.
  Ultrasonography performed by a non specialist remains safe and efficient because it is not a complete examination but only a tool to answer to a precise focused question asked prior to the US exam.
  We do not perform an ultrasound exam to see “what’s up in this patient”.
  This approach conducted by non ultrasound specialists would lead first to miss difficult to see abnormalities and second to discover ”incidentaloma” which do not interfere with pragmatic care of the patient.
  Although US is indispensable in ICU (general US or echocardiography) and could be done in most of the case by properly trained intensivists, US examinations should not be done systematically but only to answer to a delineated question.
   
  Most of the above discussed examination (pleural, peritoneal, renal) could be performed with an echocardiography machine using a cardiac transthoracic probe.
  This type of equipment is more and more frequently available in ICU.
  Vascular examination requires a different probe (5 to 7.5 MHz).
  Time has therefore come for intensivists to learn general ultrasonography.
  Radiologists, considering the huge demand of imaging modalities in the actual medicine environment (CT Scan MRI), prefer to perform only difficult US examination at the bedside rather than basic ultrasonography such as assessing the presence of a pleural effusion or a bladder overdistension .
   
  The field of limited post traumatic abdominal US exploration  (so called FAST US [Focused Assessment for the Sonography of Trauma] performed by surgeons or emergency physicians demonstrates that focused US training is efficient to provide limited answers [20].
  Whereas FAST is most of the time accurate to detect free fluid effusion the peritoneal space, its weak ability  to detect hollow organ contusion without effusion and retroperitoneal organ injury has been highlighted [21, 22].
   
  General guidelines in echocardiography training recommend around 75 to 150  procedures to be performed before being reliable.
  However accumulating evidence suggests that short (one day) or very short (some hours) training could be sufficient to acquired competence in focused investigation.
  The pivotal question is the number of normal and abnormal examinations to be acquired by the student before he will be able to detect these abnormalities.
  For hemoperitoneum detection during the FAST, the minimum of examinations to perform before being competent is  between 15 and 30 [23, 24].
  Kimura et al observed that 1 hour of lecture with 1 hour of ultrasound training followed by “hands on “training with 5 normal volunteers was sufficient to correctly assess left ventricular function [14].
  Manasia et al in surgical critically ill patients reported that a 10 hours tutorial, non cardiologists intensivists correctly interpreted  limited echocardiography  in 84% of cases [13].
  Hellman et al  suggests that following 20 hours of didactics 20 one-to-one cardiac US evaluations were required but the objectives of this training were mainly more sophisticated [19].
   
  Intensivists without knowledge in ultrasonography can correctly interpret limited general ultrasonography  after a concise focused training.
  The implementation of such a protocol spares time in patient care.
  However the learning curve and the potential therapeutic impact of such a formation remain to be determined.
   
   
References
1. Vieillard-Baron A., Charron C, Chergui K et al.(2006) Bedside echocardiographic evaluation of hemodynamics in sepsis: is a qualitative evaluation sufficient? Intensive Care Med  32:  1547-52.
2. Vieillard-Baron A.,Prin S, Chergui K et al (2003) Hemodynamic instability in sepsis: bedside assessment by Doppler echocardiography. Am J Respir Crit Care Med. 168. 1270-6.
3. Vieillard-Baron A, Slama M, Cholley B et al.(2008) Echocardiography in the intensive care unit: from evolution to revolution? Intensive Care Med 34 243-9.
4. Vignon P, Dugard A, Abraham J et al.(2007) Focused training for goal-oriented hand-held echocardiography performed by noncardiologist residents in the intensive care unit. Intensive Care Med. 33 1795-9.
5. Charron C, Prat G, Caille V et al (2007) Validation of a skills assessment scoring system for transesophageal echocardiographic monitoring of hemodynamics. Intensive Care Med. 33 1712-8.
6. Doelken, P. and C. Strange, Chest ultrasound for "Dummies". Chest, 2003. 123(2): p. 332-3.
7. Beaulieu, Y. and P.E. Marik, Bedside ultrasonography in the ICU: part 2. Chest, 2005. 128(3): p. 1766-81.
8. Lichtenstein, D., et al., Comparative diagnostic performances of auscultation, chest radiography, and lung ultrasonography in acute respiratory distress syndrome. Anesthesiology, 2004. 100(1): p. 9-15.
9. Slama, M., et al., Improvement of internal jugular vein cannulation using an ultrasound-guided technique. Intensive Care Med, 1997. 23(8): p. 916-9.
10. Vargas, F., et al., A postural change test improves the prediction of a radiological maxillary sinusitis by ultrasonography in mechanically ventilated patients. Intensive Care Med, 2007. 33(8): p. 1474-8.
11. Lichtenstein, D. and O. Axler, Intensive use of general ultrasound in the intensive care unit. Prospective study of 150 consecutive patients. Intensive Care Med, 1993. 19(6): p. 353-5.
12. Vignon, P., et al., Hand-held echocardiography with Doppler capability for the assessment of critically-ill patients: is it reliable? Intensive Care Med, 2004. 30(4): p. 718-23.
13. Manasia, A.R., et al., Feasibility and potential clinical utility of goal-directed transthoracic echocardiography performed by noncardiologist intensivists using a small hand-carried device (SonoHeart) in critically ill patients. J Cardiothorac Vasc Anesth, 2005. 19(2): p. 155-9.
14. Kimura, B.J., et al., Usefulness of a hand-held ultrasound device for bedside examination of left ventricular function. Am J Cardiol, 2002. 90(9): p. 1038-9.
15. Vigneau, C., et al., Sonography as an alternative to radiography for nasogastric feeding tube location. Intensive Care Med, 2005. 31(11): p. 1570-2.
16. Maury, E., et al., Ultrasonic examination: an alternative to chest radiography after central venous catheter insertion? Am J Respir Crit Care Med, 2001. 164(3): p. 403-5.
17. Vignon, P., et al., Echocardiographic assessment of pulmonary artery occlusion pressure in ventilated patients: a transoesophageal study. Crit Care, 2008. 12(1): p. R18.
18. Slasky, B.S., D. Auerbach, and M.L. Skolnick, Value of portable real-time ultrasound in the ICU. Crit Care Med, 1983. 11(3): p. 160-4.
19. Hellmann, D.B., et al., The rate at which residents learn to use hand-held echocardiography at the bedside. Am J Med, 2005. 118(9): p. 1010-8.
20. Boulanger, B.R., et al., Utilization of FAST (Focused Assessment with Sonography for Trauma) in 1999: results of a survey of North American trauma centers. Am Surg, 2000. 66(11): p. 1049-55.
21. Miller, M.T., et al., Not so FAST. J Trauma, 2003. 54(1): p. 52-9; discussion 59-60.
22. Poletti, P.A., et al., Blunt abdominal trauma: should US be used to detect both free fluid and organ injuries? Radiology, 2003. 227(1): p. 95-103.
23. Jang, T., et al., Residents should not independently perform focused abdominal sonography for trauma after 10 training examinations. J Ultrasound Med, 2004. 23(6): p. 793-7.
24. Shackford, S.R., et al., Focused abdominal sonogram for trauma: the learning curve of nonradiologist clinicians in detecting hemoperitoneum. J Trauma, 1999. 46(4): p. 553-62; discussion 562-4.
25. Marik, P.E. and P. Mayo, Certification and training in critical care ultrasound. Intensive Care Med, 2008. 34(2): p. 215-7.
26. Poelaert, J. and P. Mayo, Education and evaluation of knowledge and skills in echocardiography: how should we organize? Intensive Care Med, 2007. 33(10): p. 1684-6.
27. Schacherer, D., et al., Abdominal ultrasound in the intensive care unit: a 3-year survey on 400 patients. Intensive Care Med, 2007. 33(5): p. 841-4.
 
 
第二届中法危重病医学研讨会 暨 上海重症医学论坛 （2009年12月 中国 上海）
       
 
版权所有© 2006－2009，中国病理生理学会危重病医学专业委员会 Chinese Society of Critical Care Medicine