ultrasound in undifferentiated shock

Ultrasound in Undifferentiated Shock

Dr James Wheeler BSC (Hons) MBBS FACEM DDU (General)

Emergency Physician SCGH

What we will cover• What is point of care ultrasound

� SCGH ED US Service

• Shock� Definitions / Causes / Treatments

• How US may be used to investigate a patient with undifferentiated shock� Some ultrasound protocols� Limitations of US examination� Some examples of sonographic findings in particular causes of shock

• What we won’t cover:� How to perform an ultrasound� Detailed interpretation of ultrasound

Point of Care / Bedside Ultrasound• Use of US at the patients bedside to answer

specific clinical questions and assist in clinical diagnosis and management � Also help guide certain procedural treatments

(IV access, pericardiocentesis etc…)

• Advantages:� Bedside (no transfer out of dept.)� Can be accessed immediately� Nil radiation� Functional imaging (CO, PAP...)� Assessment can be adapted to fit clinical

assessment & sonographic findings

• Limitations:� Training / experience and operator dependent� Sometimes difficult to obtain certain views

(sonographic windows) in critically unwell / unprepared patients

SCGH ED US Service• Established 2005

• Internationally regarded (thanks to Ass Prof James Rippey)

• 6 DDU FACEM’s (General and Emergency), 1 Fellow, 1 Registrar� DDU = 2 years supervised US training, primary and secondary exams� One consultant rostered for EDUS 0800-1800 weekdays (afterhours as per our

rostering)

• Skills of US examination are now becoming an essential part of critical care training� Other members of the ED, and other critical care, staff have varying levels of

training and experience in critical care and procedural ultrasound

SCGH ED Service: What do we do?Diagnostic Procedural Critical Care

• Abdominal • Reproductive systems• Vascular (some)• Musculo-skeletal (some)• Cardiac• Lung• Ocular• Masses

• Vascular access (PVC, CVC, arterial)

• Effusion drainage (joint, pleural, pericardial, ascitic)

• Abscess drainage• Nerve blocks• Foreign body removal

• Cardiac arrest• Major trauma (EFAST)• Chest pain• Collapse• Shortness of breath• Sepsis (?source ?fluids

or inotropes)• Pregnancy related

abdominal pain• Undifferentiated shock

…and Education / Teaching!

Shock• Hypotension Defn:

� SBP < 90mmHg� Shock Index (HR/SBP) probably better indicator of potential shock (N 0.5-0.8, SI > 1 ?Shock)

• Shock Defn:� Life–threatening condition of circulatory failure resulting in inadequate tissue

perfusion, cellular hypoxia and END ORGAN DYSFUNCTION (confusion, renal failure, hepatic failure….)

• Undifferentiated Shock:� Shock is recognised, but the cause is unclear

Undifferentiated shock• Relatively common in ED

• Important predictor of mortality

• Different subtypes of shock require different management (that may be life-saving if done in a timely fashion)

Shock – CausesCause ExampleHypovolaemia Haemorrhage (trauma, AAA, ectopic)

GI Loss (gastroenteritis)Renal Loss (DKA)Reduced intake

Cardiogenic AMICardiomyopathyValvular failureVentricular aneurysm / rupture

Obstructive Tension PTXTamponadeMassive PEHCMAtrial myxoma

Distributive SepsisAnaphylaxisNeurogenicToxicological

Evidence – US in Shock• Overall very good agreement (90 – 100%) between the US diagnosis (~20mins post

arrival) and final diagnosis (k = 0.71 – 0.9) 1, 2, 3

• Changes in Mx:� Decreases physician diagnostic uncertainty� Increased patients with transferred from ED with a definitive diagnosis � 24.6% of patients had a significant change in the use of IV fluids, vasoactive agents, or

blood products. 2� Major diagnostic imaging (30.5%), consultation (13.6%), and emergency department

disposition (11.9%) 2

Patients evaluated with POCUS had less time on vasopressors and showed trends toward fewer days in the ICU and decreased morbidity

• Unpublished

• April 2016

• 45 patients (22 had US, 23 did not) in ICU (Portland USA)

• Assessed fluid responsiveness (resp change in IVC diameter, LVOT VTI after SLR)

• Results:� 38% reduction in time on vasopressor (p = 0.038)� Trends to reduction in hours on ventilators and

days in ICU (see next slide)� Calculated savings of ~$20,000 / patient

Impact of POCUS on therapyPOCUS group

Control group p-value

Total hours on vasopressors

36.43 58.57 0.038

Hours to 50% wean off vasopressors

22.24 40.66 0.0952

Total hours on ventilator 68.3 133.67 0.283Days in ICU 4.41 6.67 0.2

US in Undifferentiated Shock• Many different target-directed US exams developed to determine cause/s of

shock

• At SCGH ED often tailored / focused US examination to answer clinical questions relevant to the clinical assessment of the patient

• Note: US also useful in guiding treatment procedures and monitoring response to treatment in this patient group

US Protocols for Shock Assessment:The image part with relationship ID rId2 was not found in the file.

Rapid Ultrasound in Shock (RUSH)

Rapid Ultrasound in Shock (RUSH)The image part with relationship ID rId2 was not found in the file.

BestViews

Rapid Ultrasound in Shock (RUSH)The image part with relationship ID rId2 was not found in the file.

Rapid Ultrasound in Shock (RUSH)The image part with relationship ID rId2 was not found in the file.

Hypovalaemia Shock

• Haemorrhage – Ruptured AAA / Ectopic Pregnancy / Solid organ injury / Thoracic injury• GI Loss – Gastroenteritis• Renal loss – DKA• Reduced Intake

Hypovolaemia - IVC Collapse / Variability

Hypovolaemia - IVC Collapse / Variability

Hypovalemia - IP Free Fluid / Haemorrhage

Hypovalemia - IP Free Fluid / Haemorrhage

Hypovolaemia – Ruptured Ectopic Pregnancy

Hypovolaemia – AAA (?signs of rupture)

Hypovolaemia – AAA (?signs of rupture)

Aortic Dissection

Aortic Dissection

Cardiogenic Shock

• AMI• Acute valvular dysfunction• Ventricular aneurysm• Cardiac rupture• Cardiomyopathy (acute or chronic)

Cardiogenic – LV Contractility

Cardiogenic – LV Contractility

Cardiogenic - AMI – RWM AbN

Cardiogenic - AMI – RWM AbN

Cardiogenic – Pulmonary Oedema

Cardiogenic - APO & Pleural Effusions

Cardiogenic - APO & Pleural Effusions

Obstructive Shock

• Massive or Sub-Massive PE• Cardiac Tamponade• Tension PTX

Obstructive – PE

Obstructive – PE - RV Dilatation

Obstructive – PE - RV Dilatation

Obstructive – PE - RV Dilatation / Contractility

Obstructive – PE - RV Dilatation / Contractility

Obstructive – PE / Tamponade:IVC Fixed Distension

DVT

Obstructive – Pericardial Tamponade (Subcostal)

Obstructive – Pericardial Tamponade (PLX)

Obstructive – Pericardial Effusion (PLX)

Obstructive – ??Pericardial Effusion

Obstructive - ?Tension Pneumothorax

Lung Contact Point

Thoracic Aortic Aneurysm with Tamponade

Distributive Shock

• Sepsis (?source)• Anaphylaxis• High Spinal Injury• Toxicological Vasoplegia

Distributive – Intraperitoneal Gas & Fluid

Distributive – ?Sepsis Source

References:

1. Ghane et al. Accuracy of Rapid Ultrasound in Shock (RUSH) Exam for Diagnosis of Shock in Critically Ill Patients. J Emerg Trauma Shock. 2015 Jan-Mar;8(1):5-10.

2. Shokoohi et al. Bedside Ultrasound Reduces Diagnostic Uncertainty and Guides Resuscitation in Patients With Undifferentiated Hypotension. Crit Care Med. 2015 Dec;43(12):2562-9

3. Volpicelli et al. Point-of-care multiorgan ultrasonography for the evaluation of undifferentiated hypotension in the emergency department. Intensive Care Med (2013) 39:1290–1298