Echocardiography on ICU

A 50 year old female presented with acute kidney injury and sepsis.  She required fluid resuscitation, haemofiltration and cardiovascular support for 2 days, following which she was discharged to the renal ward for on-going haemodialysis. She underwent dialysis every 2-3 days for the next 3 weeks. Whilst on the ward she deteriorated acutely one evening, developing respiratory distress, followed by a respiratory arrest. She was intubated and ventilated transferred to the critical care unit.

A CTPA was negative for pulmonary embolus, but showed large bilateral pleural effusions. Tracheal suctioning was initially clear but later copious blood stained secretions were removed. A bedside cardiac echo performed by the consultant intensivist showed a globally sluggish left ventricle, which was overfilled, and the inferior vena cava measured 3cm also suggesting fluid overload. A trial of furosemide failed and she was aggressively haemofiltered to remove the excess fluid. Troponin was only mildly raised, and not thought to be suggestive of an acute cardiac event. She was extubated 24 hours later, but had two further episodes of flash pulmonary oedema requiring non-invasive ventilatory support whilst haemofiltration was re-commenced for fluid balance reasons. In total twelve litres of fluid were removed, with significant improvement in the patient’s condition. Repeat echocardiography prior to discharge showed an improving left ventricular function and IVC measurement of 2cm with greatly increased compliance.

What is the evidence that focussed echocardiography helps guide decision-making in intensive care?

Katherine Francis

Echocardiography is becoming more popular as an investigation in the intensive care setting, and with the advent of echocardiography training and fellowships for intensivists, the future will see more doctors trained in this skill. This may make it more feasible out of hours to obtain a focussed echocardiogram. The ability to rule out ventricular wall motion abnormalities or pericardial effusions and assess LV function and LV volume status can guide specific treatments or interventions.

Zhang et al1 reported that after only 12 hours of teaching, intensivists successfully performed a focussed TTE in 98%, and correctly interpreted the results in 85%. This led to a change in patient management in 22% of cases, varying from fluid management to vasoactive or inotropic agent choice. In 45% of cases the study provided useful patient information, whilst in only 32% was the study felt to be non-valuable. The mean acquisition study time was 11.2 minutes.

Various other countries have also tried to set up their own accreditation system for echocardiography in Intensive Care, recognising it’s value. In Spain, Ayuela Azcarate et al2 have written a consensus document from their working group in 2013 determining levels of knowledge required and the application of echocardiography. They discuss the need for a structured training process for acquisition of this important skill and the need for accreditation through scientific societies. The Swiss were slightly ahead, Giraud et alreporting in 2009 of their working party panel of experts set up to define competence in critical care ultrasonography. They created a reasonable minimum standard statement in order for proficiency to be achieved.

Price et al in London published a similar document from the WINFOCUS group4, commenting in 2008 on the lack of specific guidelines for ICU physicians wishing to incorporate echocardiography into their clinical practice. They offered guidelines to various British and European societies about building an ICU based echocardiography service, and covered key components of standard adult TTE and TOE studies for the ICU. They advise that training be completed either through a dedicated fellowship/ training scheme or via a staged approach, with peri-resuscitation focused echocardiography representing the entry level. The modular programme is envisaged to be course led with mentor support, to make accreditation achievable within the existing framework of clinical practice.

The idea of extending focused echocardiography from basic peri-arrest ultrasound imaging is not new. The focused use of sonography in trauma (FAST scan) patients in the emergency department has been in use for a number of years and has been extended to include scanning the anterior chest wall looking for pneumothoraces (eFAST). This has been shown to have higher sensitivity and quicker access times compared to CT scanning5. Breitkreutz el al support the addition of focused echocardiography in the peri-resuscitation of patients (FEEL scan), demonstrating with a prospective trial of pre-hospital cardiac arrest and shocked patients. The trial looked for coordinated cardiac motion on the echo, and if found, this was associated with increased survival chances in patients with asystole or PEA rhythms. The use of the FEEL scan altered management in 78% of cases6,7.


 

Lessons learnt

We depend frequently on the rapid assessment of a critically ill patient to guide investigations and plan treatment, with increasing opportunity for bedside testing. Training is an important step, and frequent use of a skill is necessary to maintain competence. Therefore it is unnecessary to train everyone working on the intensive care unit in the use of focused echocardiography. Units should identify key personnel and offer training, as this has been shown to be feasible and beneficial. Other doctors could have a basic understanding of image interpretation. The opportunity to have focused echocardiography available on an Intensive Care Unit or with resuscitation can only help our patients and guide the treatment they receive.


 

References

  1. Zhang LN et al Feasibility of focused transthoracic echocardiography in intensive care unit performed by intensivists. Zhongguo Wei Zhong Bing Ji Jiu Yi Xue. 2012 Dec;24(12):739-41.
  2. Ayuela Azcarate JM, Clau-Terre F et al Consensus document on ultrasound training in Intensive care Medicine. Care process, use of the technique and acquisition of professional skills. Med Intensiva 2013 dec 3 pii:S0210-5691 (13)00158-7.
  3. Giraud R et al Evaluation of practical skills in echocardiography for intensivists. Rev Med Suisse 2009 Dec 9;5(229):2518-21
  4. Price S et al World Interactive Network Focused on Critical Ultrasound ECHO-ICU group. Echocardiography practice, training and accreditation in the intensive care: document for the World Interactive Network Focused on Critical Ultrasound (WINFOCUS). Cardiovasc Ultraosund 2008 Oct 6;6:49.
  5. Kirkpatrick AW, Sirois M, Laupland KB, et al. J Trauma, 2004;57(2):288–95
  6. Breitkreutz R et al. Focused echocardiographic evaluation in life support and peri-resuscitation of emergency patients: a prospective trial Resuscitation 2010 Nov;81(11): 1527-33
  7. Breitkreutz R et al Focused echocardiographic evaluation in resuscitation management: concept of an advanced life support conformed algorithm. Crit care Med 2007 May;35 (5 Suppl):S150-61
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