CIRCULATORY FAILURE `Shock` David Walker Critical Care Consultant University College London Hospitals Or `what to do with the blood pressure, when you don’t know what to do with the blood pressure`!

Confused elderly lady, limited story, limited PMH, no true diagnosis, BP 80/45 (And the smart ass medical registrar has done everything) Do you: 1.Covertly set off your bleep and leave the ward? 2.Fake illness and go home? 3.Pop to the WC and weep? 4.Do your best – even when you know your best might not be enough? DO NOT CRY IN FRONT OF THE PATIENT Ask yourself - is this blood pressure adequate?

Shock: (Significant tissue oxygen debt (impaired organ oxygenation..or utilisation)... frequently a case of too little, too late! Shock is often defined as a low blood pressure state IMPORTANT shock can exist despite a normal BP A low BP may be compatible with adequate organ perfusion Clinicians often don’t react until the BP falls...

Clinical situation There are two situations in which you might be alerted to a ‘poor circulation’: 1. Low blood pressure is recorded 2. Effects of low flow or perfusion Brain Kidney Acidosis

The golden hour Don`t wait until the morning

Principals Pump (heart) Resistance (vessels) Flow (CO)

It’s the same old story in AAU: Confused elderly lady, limited story, limited PMH, no true diagnosis, BP 80/45 Mean arterial BP (MAP) = systolic + (diastolic x 2) 3 BP 120/80: MAP 93 mmHg = (80 x 2) 3 MAP >65 is a good starting point (but may need to be higher)

PRESSUREFLOWRESISTANCE

Sympathetic response

PRESSURE (Surrogate) FLOW (of interest) RESISTANCE (who knows!) CO = MAP/SVR (this equations has 2 unknowns!) (Significant tissue oxygen debt (impaired organ oxygenation..or utilisation)

Mean Arterial PressureAPACHE II points <504 Blood pressure – It does matter!

Management Confused elderly lady, limited story, limited PMH, no true diagnosis, BP 80/45 Step one – Make the diagnosis  Back to the history (its often all there)  Careful examination  What tests corroborate diagnosis?

1. Cardiac output (low flow shock) 2. Vascular resistance (low resistance) CO SVR CO

LOW BP? OR SIGNS OF LOW PERFUSION

HR increase cold sweaty clammy tachypnoea

Causes: 1. Hypovolaemic 2. Cardiogenic 3. Pulmonary embolus 4. Tension pneumothorax 5. Cardiac tamponade

 Inappropriately dilated  Febrile usually  Large volume pulse & Signs of low organ perfusion

 Septic shock  Anaphylaxis

What can & should we measure? pH and lactate End organ perfusion Scv O2 MAP CVP

SVO2>70% Extraction of Oxygen

Airway Breathing Circulation

SHOCK PRELOADAFTERLOAD PUMP (ENERGY IN) ‘MECHANICS’

pre-load The greater the stretch the greater the force of contraction

underfilled PAWP / CVP BLOOD VOLUME filled ≥3mmHg well-(over)-filled fluid challenge 24 Filling – What is the concept?

What is a fluid challenge Lactate pH Scv O2 BP/Pulse CVP Brain Heart Kidney Resp Reassess

Pulmonary oedema = excess lung water Does not always equal excess vascular water Patient could be volume deplete and have pulmonary oedema CAREFULLY, but remember

RAP is a poor correlate of cardiac output But measure it and watch for changes Careful not to over interpret

Oesophageal Doppler – measures flow a better concept…..

Contractility Afterload Only when the circulating volume optimised - consider:-

Squeeze – (afterload) (vasopressor) Pump – (contractility) (inotrope) CO = MAP/SVR MAP = CO x SVR Drugs Adrenaline Nor- adrenaline

CARDIOGENIC SHOCK Problem – the pump don’t work!  CALL FOR HELP  Oxygen, IVI, monitoring, sit up  GTN (Off loading)  Support the ventricle  Diuresis (CAUTION)

Monitor pressure Monitor filling Monitor stroke volume if able (Clinical, neck lines, swans, Dopplers) NEED TO MONITOR TISSUE PERFUSION (Clinical- skin, brain, kidney and acid) CARDIOGENIC SHOCK Problem – the pump don’t work!

HYPOVOLAEMIC SHOCK Problem – The circulation is empty  CALL FOR HELP  Oxygen,IVI Fluids  Blood cross match  Definitive therapy Remember:  Young healthy people compensate for blood loss well  Haemoglobin not a reliable indicator of blood loss in acute situation

ANAPHYLAXIS Problem – the circulation is inappropriately dilated  STOP offending drug  Call Help, give high flow oxygen  IVI, colloid bolus running  Adrenaline 1mg ( 1ML 1 in 1000) i.m.  Or 100 Mcg i.v. boluses with cardiac monitoring  (Steroid / antihistamine / Mast cell tryptase)

SEPTIC SHOCK Problem - The circulation is inappropriately dilated  CALL FOR HELP  Oxygen, IVI, Fluids  Cultures  Antibiotics  Monitor  Vasopressors Google: surviving sepsis campaign

Pulmonary embolism Problem - Blood can’t get into left side of heart (empty)  Oxygenate, IVI and colloid challenge  Lie flat  Support the right ventricle  Thrombolysis (see BTS guidelines)

Tension Pneumothorax Problem - Heart moved to one side, veins kinked, prevents left sided filling  Call help  Give oxygen, IVI,  ATLS guidelines  Chest drain  CXR is last on your list!

Pericardial tamponade Problem - Pericardial sac filled with fluid & presses on heart and stops it filling  You need help!  Oxygen, IVI - Fill the circulation  Lie flat  Decompression is needed  CXR may not help diagnosis

You are never alone! DO CALL: Registrar / Outreach nurses / ICU  Don’t just treat oliguria with Frusemide  OR confusion with sedatives  Never cry in front of the patient!

QUESTIONS? Happy doctors