In the first 15 minutes…
Triage, Stabilization, and Therapeutic Considerations in Shock
Rebecca Walton, DVM, DACVECC Clinical Assistant Professor of Emergency and Critical Care
ISU-IVS Partners in Progress CE Event April 3, 2019
Shock – definition
• Shock is defined as a state of cellular and tissue hypoxia secondary to: – Reduced tissue perfusion – Decrease in oxygen delivery – Increase in oxygen consumption – Inadequate oxygen utilization
Classification and etiology
• 4 types of shock – Hypovolemic – Distributive – Cardiogenic – Obstructive
https://acls-algorithms.com/rhythms/pulseless-ventricular-tachycardia/
Hypovolemic shock
• Decreased intravascular volume
• 2 main categories – Hemorrhagic – Non-hemorrhagic • Gastrointestinal loss • Renal loss • Third space • Skin loss
Distributive shock
• Characterized by severe peripheral vasodilation
• Underlying etiology – Septic shock – Systemic inflammatory
response syndrome – Neurogenic shock – Anaphylactic shock – Drug/toxin – Endocrine shock
Cardiogenic shock
• Intra-cardiac causes of cardiac pump failure resulting in decreased cardiac output
• Categories – Cardiomyopathic – Arrhythmic – Mechanical
https://www.merckmanuals.com/professional/cardiovascular-disorders/arrhythmias-and-conduction-disorders/atrioventricular-block
Obstructive shock
• Extra-cardiac causes of cardiac pump failure and are associated with decreased right ventricular filling and poor right sided cardiac output
• Categories – Pulmonary – Mechanical
http://www.coolspringsah.com/our-blog/2014/6/18/seriously-scary-gdv
Physiologic variable
Preload - volume
Pump function – Cardiac output
Afterload – systemic vascular resistance
Hypovolemic
Cardiogenic
Distributive
Obstructive
Compensatory mechanisms
• Mobilization of fluid from the interstitial space to the intravascular space
• Activation of the sympathetic nervous system – Increase heart rate/blood pressure
• Activation of the renin-angiotensin aldosterone system – Regulate blood pressure – Fluid retention
• Release of anti-diuretic hormone – Water reabsorption
Stages of shock
• Compensated shock***
• Decompensated shock
• End stage shock
http://www.dogscatspets.org/dogs/pale-gums-in-dogs/pale-gums-dogs-lethargic-causes-treatment-white-gums-dogs/
Stages of shock - compensated
• Compensatory mechanisms – Increased cardiac output – Tachycardia – Fluid retention
Stages of shock - decompensated
• Compensatory mechanisms are overwhelmed
• Hypotension • Pale mucous membranes • Poor pulse quality • Signs of organ dysfunction occur
Stages of shock - end stage
• Irreversible organ damage • Multiple organ failure • Systemic acidemia • Hypotension
Clinical signs
• Compensated shock – Pale mucous membranes – Prolonged CRT – Cold extremities – Tachycardia – Dull mentation – Blood pressure usually NORMAL
Clinical signs
• Decompensated shock – Local tissue beds begin to vasodilate – Vasodilation leads to blood pooling • Maldistribution
– Grey mucous membranes – Bradycardia – Hypotension – Altered mentation
Clinical signs – cats
• Unique challenge – they do not display classic signs of shock like dogs
• Clinical signs – Bradycardia – Hypothermia – Hypotension – **even in the early stages of shock**
Triage
• Triage is derived from the French work trier – Refers to the sorting of all patients for
treatment priority • Triage refers to a systemic evaluation of
body systems and is designed to facilitate identification of the most life threatening problems first
• Patients with life threatening abnormalities require timely intervention
Triage history
• The formal concept of triage began in the late 1700’s when two French surgeons were faced with massive casualties associated with the European wars
Triage systems – human medicine
• Triage systems have been used in people to improve the acuity of triage
• 5 level system – Resuscitation – Emergent – Urgent – Less urgent – Non-urgent
• System is generally based on vital signs and presenting complaints
“Undertriaging”
• ~30% of human patients ‘stable’ on admission with normal vitals deteriorate 2-24 hours after admission
• Triage scoring systems aim to – Predict survival – Determine severity of illness to prioritize
treatment
Triage – veterinary
• Used to describe the sorting of animals in the emergency department or general practice based on medical priority – Sickest treated first
• Rapid, accurate triage is essential
Secondary survey
• Evaluates systems from the primary survey in more depth – Thoracic auscultation – Additional assessments • Abdominal palpation
– Performed at a slower pace – Nose to tail physical exam
Triage exam
• On arrival to the hospital this triage assessment should be performed
• TRIAGE EXAM SHOULD BE PERFORMED ON EVERY PATIENT
• Brief history – Signalment – Presenting complaint
• Triage exam
Other conditions that warrant immediate evaluation even if the triage exam deems the patient stable
– Severe pain – Recent toxin ingestion – Signs of intoxication – Recent seizures – Trauma – Active bleeding
– Hyperthermia/hypothermia – Open wounds – Fractures – Burns – Dystocia
Other
Triage – cardiovascular
• Purpose – Identify poor tissue perfusion and decreased
tissue oxygen delivery
• Without rapid identification of inadequate tissue perfusion – Critical tissue hypoxia – Multiple organ dysfunction – Death
Triage - cardiovascular• Heart rate • Pulse quality – Femoral/Dorsal pedal
• Temperature – Rectal and extremities
• MM/CRT
• ECG
• Doppler Blood Pressure
Normals: • Heart rate
• Dog: 60-120 • Cat: 160-220
• Temperature • 99.5 – 102.5 F
• Mucous membranes • Pink
• Capillary refill time • 1-2 seconds
Alterations in sympathetic tone • Volume deficit • Oxygen deficit • Pain/anxiety = stress • Cardiac dysfunction
Triage - cardiovascular• HR • Pulse Quality – Femoral/Dorsal pedal
• Temperature – Rectal and extremities
• MM/CRT
• ECG
• Doppler Blood Pressure
Normals: • HR
• Dog: 60-120 • Cat: 160-220
• Temp • 99.5 – 102.5
• MM • Pink
• CRT • 1-2 seconds
Alterations in sympathetic tone • Volume deficit • Oxygen deficit • Pain/anxiety = stress • Cardiac dysfunction
Tachycardic rule-outs • Type
• Sinus vs. supraventricular vs. ventricular tachycardia
• Cause • Hypovolemia • Hypoxemia • Anemia • Cardiac disease • Pain/anxiety/stress/drugs
Triage - cardiovascular• HR • Pulse Quality – Femoral/Dorsal pedal
• Temperature – Rectal and extremities
• MM/CRT
• ECG
• Doppler Blood Pressure
Normals: • Heart rate
• Dog: 60-120 • Cat: 160-220
• Temperature • 99.5 – 102.5 F
• Mucous membranes • Pink
• Capillary refill time • 1-2 seconds
Alterations in sympathetic tone • Volume deficit • Oxygen deficit • Pain/anxiety = stress • Cardiac dysfunction
Bradycardic goodness • Associated with normal cardiac output
• Normothermia, normotension • Increases with stimulation • Resting sinus arrhythmia
Bradycardic badness • Associated with ! cardiac output
• Hypothermia, hypotension • Unable to increase HR with sympathetic
stimulation • Associated with high BP, dull mentation
(Cushing reflex)
Pulse quality
• Pulse quality – Location
• Femoral + " systolic 60 mmHg • Dorsal pedal + " systolic 90 mmHg
– Width: systolic – diastolic pressure
Normal Thready
Indirect BP measurement
• Doppler – More sensitive measure of systolic pressure • Correlates more with MAP in cats
– Preferred method in patients with low blood pressure/ arrhythmias
• Oscillometric – More sensitive measure of mean pressure – Preferred method in anesthetized patients
Triage - cardiovascular
• Shock Index (SI) – SI = heart Rate (HR) / systolic blood pressure
(BP)
• Advantages – Sensitive marker of compensatory shock • Detect perfusion deficits despite normal HR, BP
– SI > 0.9 • Differentiate dogs in hemorrhagic shock from
stable dogs
Cardiac auscultation
• Arrhythmias – Can be associated with systemic or cardiac
disease
http://cal.vet.upenn.edu/projects/anestecg/Basics/Arrhythm/vfl100fr.htm
Cardiac auscultation
• Murmurs – Indication of
turbulent blood flow – Commonly
associated with • Valvular disease • Stenosis • Altered blood
viscosity • Congenital
abnormalities
http://vetmed.ucdavis.edu/vmth/small_animal/cardio_kittleson/cases/Echocardiograms/Echo%20I/echo_1.htm
Cardiac auscultation
• Muffled heart sounds – Effusion • Pericardial • Pleural
– Mass
http://www.stritch.luc.edu/lumen/MedEd/Radio/curriculum/Medicine/Pericardial_effusion2.htm
Mucous membrane color
• Cyanosis – Indicates severe hypoxemia – Definition: greater than 5 g/dL of desaturated
hemoglobin • Correlates to an SpO2 of 75% • PaO2 40 mmHg
– SEVERE hypoxemia – Immediate intervention
required • Oxygen therapy • Intubation
http://www.caninepulmonaryfibrosis.ulg.ac.be/about-ipf/
Mucous membrane color
• Pallor – Severe vasoconstriction • Increased sympathetic
outflow associated with shock states • Leads to peripheral
vasoconstriction
– Anemia
https://www.google.com/search?biw=1205&bih=801&tbm=isch&sa=1&ei=JFWeXOWnI43aswWshKrYCg&q=blood+loss+raas+activation&oq=blood+loss+raas+activation
Mucous membrane color
• Injected/red mucous membranes – Decreased cellular oxygen utilization • Cyanide
– Severe vasodilation
Mucous membrane color
• Petechiation/ecchymosis – Coagulopathy – Thrombocytopenia – Thrombocytopathia
https://www.google.com/search?biw=1205&bih=801&tbm=isch&sa=1&ei=plWeXMf7KYXwsQXJ77mICA&q=dog+petechiation&oq=dog+petechiation
Capillary refill time
• Assessment of perfusion – Blanch mucous membranes
• Slow refill " high arteriolar tone – VASOCONSTRICTION
• Rapid refill " low arteriolar tone – VASODILATION
• Slow refill time – Low cardiac output
• Rapid refill time – Distributive shock – Sepsis/SIRS
Triage -respiratory
• Evaluation should be focused on determining the presence or absence of – Hypoxemia – Hypoventilation
• Assessment of respiratory rate and effort • Airway patency should be assessed – Obstruction - exaggerated effort – Lower respiratory disease – prolonged
expiration
Triage - respiratory
• Rate • Effort • Localization
Normals: • RR
• Dog: 10-12bpm • Cat: 10-30 bpm
• SpO2
Tachypnea
normal SpO2 low SpO2
Pain/anxiety Hyperthermia Metabolic acidosis CNS disease
Parenchymal disease Pleural space disease Airway
Pulse oximetry
• Surrogate marker of PaO2
– Hgb saturation with oxygen is directly correlated with SpO2
• Provides no marker of oxygen delivery • Tends to underestimate when > 90% and
overestimate when < 80%
Feline respiratory evaluation
• Unique feline considerations • Clinical signs
– Increased respiratory rate/effort – Open mouth breathing
• Minor manipulations may result in decompensation – Physical exam – Intravenous catheter placement
• May benefit from being placed immediately in oxygen
• Sedation
Pulmonary auscultation
• Fine crackles – Associated with opening and closing of collapsing
alveoli – Usually due to fluid in the alveoli – Common causes:
• Pulmonary edema • Contusions • Pneumonia
• Coarse crackles (rhonchi) – Large airway disease – **always listen over
trachea
https://www.google.com/search?biw=1205&bih=801&tbm=isch&sa=1&ei=slWeXPKkLoiWsgWquajoDw&q=dog+radiograph+alveolar+pattern&oq=dog+radiograph+alveolar+pattern
Pulmonary auscultation
• Increased bronchial sounds – Increased movement
through large airways – Causes
• Panting • Bronchial disease
• Dull lung sounds – Commonly associated
with pleural space disease
http://www.aecrockford.com/ef-digital-radiology/
Pulmonary auscultation
• Wheezes – Squeaking/high pitched whistling noise – Associated with air movement through
narrowed airway – Common causes • Asthma • Tracheal narrowing/mass
http://www.thetiger-club.com/feline-asthma/
Triage - neurologic
• Modified Glasgow Coma Scale (MGCS) – Motor activity – Brainstem reflexes
• Pupil size • Pupillary light reflex
– Level of consciousness • Consciousness most reliable measurement
Triage - urologic
• Acute kidney injury or urinary obstruction can lead to: – Metabolic acidosis – Hyperkalemia – Cardiac arrhythmias – Death
Triage - urologic
• Is bladder palpable and expressible? • FAST scan to aid visualization – Intact bladder does not rule out bladder
rupture
Abdomen
• Quick abdominal palpation – Pain – Distention • Organomegaly • Effusion • Gastric dilation
Triage • The triage exam should be performed in any patient
presenting to the emergency department/general practice
• Goal of triage exam: identify shock states and patient with poor tissue perfusion
• Identify those requiring immediate intervention • Triage systems
– Cardiovascular – Respiratory – Neurologic – Urologic
• Secondary survey and “tip of nose to tip of tail” physical exam should be performed once primary survey is complete and patient is stable
Diagnostics
• During placement of the intravenous catheter blood drawn: – Minimum database • PCV/TS • Glucose • Azo • Lactate • Blood smear • Venous blood gas
Diagnostics
• Minimum database • PCV/TS • Blood glucose • Lactate
• Blood gas • Ventilation • Electrolyte/acid-base status • Perfusion (lactate, BE)
• Imaging (second tier) • Thoracic/abdominal imaging
Diagnostics
• PCV/TS hold clues… – TS < 6.0 g/dL • Suggestive of acute hemorrhage • PCV nadir doesn’t occur for 24-48 hour
Blood lactate
• Lactate is the product of anaerobic metabolism
• Occurs with inadequate tissue oxygen delivery
• Prognostic indicator • Goal directed therapy
https://lactateplusmeter.com/
FAST scan
• AFAST • TFAST
Assess for free fluid, air, intact bladder (urinary and gallbladder)
FAST scan compared to CT • Excellent agreement for detection
of fluid • Poor agreement for detection of
air
FAST scan – air/fluid check
Abdominal • Diaphragmatic-hepatic
Thoracic • Bilateral chest tube site views • Pericardial site view • Diaphragmatic-hepatic (subxiphoid)
view • Absence of glide sign--
pneumothorax
• Hepato-renal • Cysto-colic• Spleno-renal
Monitoring tissue perfusion and oxygenation
• Well perfused patient possesses: – UOP > 1 ml/kg/hr – MAP 70-120 mmHg – Normal temperature – Normal heart rate and rhythm – Pink mucous membranes – CRT < 2 seconds
Resuscitation end points
• Physical exam parameters – Heart rate – Pulse quality – CRT – Extremity temperature – Mentation
• Normalization of blood pressure • Normalization of lactate • Urine output
Treatment of shock states
• Hypovolemic
• Distributive
• Cardiogenic
• Obstructive
Improve preload – fluid bolus
Improve afterload – fluid bolus/vasopressors
Improve contractility – positive inotrope
Relieve obstruction – trocharization/ pericardiocentesis
Improve preload
• Rapid administration of intravenous fluids to restore effective circulating volume
• Vascular access – Speed of volume administration is
proportional to the catheter lumen and inversely proportional to length • Short • Large bore
Improve preload – fluid type
• Replacement crystalloids – Lactated ringers – Normosol R
• Shock dose – 90 mL/kg (dog) 60 mL/kg (cat)
– Give in 10 ml/kg increments and reassess • Rapid redistribution into the extracellular space
– 25% remains in the intravascular space after 30 minutes
• Hypertonic saline – Small volume 3-5 mL/kg over 10 minutes
Blood volume
Improve preload – fluid type
• Blood component therapy – Often used during resuscitation
• Used for acute blood loss that is unresponsive to fluid therapy alone
• Components – Fresh whole blood – Packed red cells – Plasma
• Maintain HCT > 25%
Improve afterload
• Fluid therapy – Can aid in restoring circulating volume in
situations of vasodilation
Improve afterload
• Vasopressor therapy – Catecholamines • Norepinephrine • Epinephrine
– Vasopressin
Improve contractility
• Positive inotropy – Pimobendan • Inodilator • Inhibit phosphodiesterase III • Increased calcium availability • Oral ONLY
– Dobutamine • Beta-1 agonist • Improve contractility
https://www.1800petmeds.com/Vetmedin+%28pimobendan%29-prod10980.html
Relieve obstruction
• Gastric dilatation and volvulus – Gastric decompression • Trocharization • Orogastric intubation
• Pericardial effusion – Pericardiocentesis
Fluid therapy
• KEY POINT – Fluid will help in almost all etiologies of
shock – EXCEPT cardiogenic shock – Fluid administration WILL be harmful to dogs
with cardiogenic shock – ALWAYS try to ensure dogs are not in
cardiogenic shock
Oxygen therapy
• Provide flow-by • Place in sternal recumbency (if possible)
• PaO2 increases by 17.4 mmHg
Pain management
• Address hemodynamic status FIRST! • Selection – Reversible, titratable – Remember side effects
• Common drugs – Opioids • Fentanyl " CRI • Hydromorphone " bolus, possible emesis/
panting
Stabilization endpoints
• Maintain blood pressure and perfusion • Pink MM, CRT 1-2 seconds • Strong peripheral pulses • Normal HR • Doppler BP maintained above 100 mmHg
• Maintain oxygenation • Maintain SpO2 above 94%
• Maintain ventilation
Conclusions
• Triage with additional data – Blood pressure – SpO2 – ECG – +/-FAST – PCV/TS/blood gas
• Stabilize – IVF – Oxygen support – Pain control
Serially Examine