Perioperative hypotension

Hypotension Validation

Hypotension Validation

* Check NIBP monitor - repeat cycle, check cuff size, check manually
* Confirm with palpation of large artery for pulse
If no pulse, manage as for CARDIAC ARREST
* Check Arterial line
Flush
Open to air and quickly confirm zero
Pulsatile waveform
* Independent pulse source - SpO2
* Has ET CO2 level fallen?
Low ETCO2 = Low Cardiac Output or Embolism

Critical Management 1

Critical Management 1

* 1. Increase Inspired OXYGEN
* 2. Is the hypotension EXPECTED?
Is it the result of an anticipated surgical intervention ?
If YES then manage in context of surgical causes
* If UNEXPECTED, quickly check that there are no obvious surgical issues e.g.
Sudden massive blood loss
IVC compression (including obstetrics / laparoscopy)
Femoral shaft reaming etc.
CO2 insufflation
Tourniquet or Vascular Clamp release

Critical Management 2 - Check ECG

Critical Management 2 - Check ECG

* If Asystole / VF or pulseless VT then manage CARDIAC ARREST
* If TACHYARRHYTHMIA (AF/SVT/VT) then
Control rate with Vagal Manouvres / Vagotonic Drugs or Synchronized Cardioversion
Review possible causes including LIGHT ANAESTHESIA
* If SEVERE BRADYCARDIA then
Increase rate with Vagolytic agents (atropine)
Use chronotropic pressors (ephedrine, adrenaline)
Review possible causes including HYPOXIA

Critical Management 3 - Provide circulatory support

Critical Management 3 - Provide circulatory support in presence of normal rhythm

* 1. Volume resuscitation
First priority in context of recent neuraxial block
IV fluids
Posture legs up (if practical)
Consider wide-bore access
* 2. Vasopressors
Especially if GA or unresponsive to volume or limited ability to rapidly infuse fluids
Ephedrine / Metaraminol / Phenylephrine / Noradrenaline / Adrenaline / Vasopressin

Critical Management 4 - Assess CAUSE

Critical Management 4 - Assess CAUSE and provide SPECIFIC treatment

* Consider likely causes of SEVERE HYPOTENSION
Sudden BLOOD LOSS (surgical)
Impaired VENOUS RETURN (surgery / posture / high airway pressures / pneumothorax)
VASODILATION (neuraxial block - assess block height, anaesthetic agents, drug reactions including ANAPHYLAXIS)
EMBOLISM (Air / CO2 / orthopaedic / venous thromboembolism)
CARDIAC DYSRHYTHMIA
CARDIAC Dysfunction
Ischaemia / Infarction
Depressants (anaesthetic agents etc)

Critical Management 5 - Continue to Support Blood Pressure

Critical Management 5 - Continue to Support Blood Pressure

* If still severely hypotensive
Call for assistance
* Review Likely Causes If cause still not determined : Perform Systematic Review of
AIRWAY
o Pressures
o Minute Volume
BREATHING
o CO2 exchange
o Oxygenation
CIRCULATION
o Rhythm
o Ischaemia
o Volume (insert CVC / PAC / TOE)
DRUGS
o Check doses
o agents
* Consider other RARE CAUSES

Non-critical Management 1

Non-critical Management 1

* Validate reading
* Attempt to IDENTIFY CAUSE
* Treat by
CORRECTING CAUSE
DECREASING ANAESTHETIC DEPTH (if GA)
VOLUME (IV or posture)
VASOPRESSORS (if unresponsive to other measures)

Non-critical Management 2 - Common causes

Non-critical Management 2
Identify and Treat COMMON CAUSES of Mild to Moderate Intraoperative Hypotension

* Relative HYPOVOLAEMIA
Neuraxial BLOCK (assess block height), inadequate fluid replacement
* Excessive relative DEPTH of ANAESTHESIA
Volatile agent / IV agent too high
* High AIRWAY PRESSURES
* SURGICAL
Blood Loss
Venous Return Compression
Release of tourniquet or vascular clamp
* Mild RHYTHM disturbance
Nodal rhythm, slow AF

Non-critical Management 3 - Systematic assessment

Non-critical Management 3
If unable to identify a cause at this stage, proceed to a more thorough systematic assessment

* Perform Systematic Review of
AIRWAY
o Pressures / Minute Volume
BREATHING
o CO2 exchange
o Oxygentaion
CIRCULATION
o Rhythm
o Ischaemia
o Volume (insert CVC / PAC / TOE)
DRUGS
o Check doses
o agents
* Consider RARE CAUSES

Rare Causes of Intraoperative Hypotension

Rare Causes of Intraoperative Hypotension

* Anaphylaxis
* Drug Error
* Transfusion Incompatibility
* Acute Mitral Valve Rupture
* Pericardial Tamponade
* Septic Shock
* Adrenocortical Insufficiency