Anaesthesia and analgesia for the trauma patient Flashcards
When triaging a trauma patient, what factors will you focus on?
What modalites will you use to assess a patient and what values are important here?
Focus on major body systems assessment: Heart rate, respiratory rate, thoracic auscultation, peripheral pulse quality, mentation, pupil size, PLR, temperature etc. [Ignore things not of immediate consequence to the animal].
Pulse oximetry: Values less than 95% may indicate hypoxaemia (corresponding to a partial pressure of oxygen [PaO2] < 80 mmHg)
ECG: Haemodynamically unstable animals may develop arrhythmias
Blood pressure monitoring: Doppler or oscillometric monitoring to determine the presence of hypovolaemic shock and need for fluid resuscitation. [Doppler blood pressure measurement** < 80-90 mm Hg** may represent shock in both cats and dogs].
POCUS, blood gass analysis (EPOC), PCV/TS
What are the inital steps with a trauma patient?
- triage (assess parameters)
- supplemental oxygen, and low stess
- analgesia
What analgesia should be used with trauma patients?
What should be avoided, why?
- Methadone or fentanyl: full mu agonists
- Ketamine: NMDA receptor antagonist
- Paracetamol: can be used as an adjunct
[Avoid NSAIDs and alpha-2 agonists in patients with cardiovascular instability]
[Consider giving IM opioid if vascular access not easily and rapidly obtained]
What are the key aspects of vascular access in trauma cases?
Gain vascular access as soon as possible:
* Ideally place two peripheral catheters
* Widest bore possible
* Avoid injured limbs!
* [Other options in patients with injured limbs: intraosseous, jugular (pink or green), auricular]
What are the aims of stabilisation of a trauma patient?
- To provide analgesia
- Improve haemodynamics
- Improve ventilation
- Improve oxygen carrying capacity.
- Mitigate the effects of anaesthetic drugs on body systems - Reduce the risk to the patient
Want to improve blood pressure, oxygen saturation
If you have a trauma case that is haemorrhaging what are the principles of stabalisation?
Fluid resuscitation (hypotensive resuscitation - aim for o blood pressure a little low to stop bleeding), consider need for transfusion, consider body bandage for haemabdomen if cost concerns, give tranexamic acid (TXA).
What are the principles of stabilistion for trauma cases with head trauma?
Monitor and maintain blood pressure (CPP = MAP – ICP), provide supplemental oxygen, take steps to improve ventilation, consider hypertonic saline or mannitol
What are the principles of Stabilisation in haemothorax/pneumothroax trauma cases?
Thoracocentesis to allow lung expansion and improve saturation, supplement oxygen.
What are the principles of stabilisation in fracture cases
Splint or bandage as appropriate (need lots of analgesia and don’t try to reduce in conscious patient though).
What premedication should you use with trauma cases?
What other medication can you give pre-operatively?
Opioid IV / Opioid + benzodiazepine IV
+/- ketamine IV (can cause respiratory depression on induction)
+/- alfaxalone [fractious cat] IM (off licence)
* Avoid acepromazine and alpha-2 agonists in patients with cardiovascular instability
other:
* Anti-emetics [e.g. maropitant, ondansetron]
* Gastroprotectants [e.g. omeprazole]
* Antibiotics [e.g. cefouroxime, amoxiclav]
* Adjunctive analgesia [paracetamol, ketamine CRI etc.]
What is the mechanism of action of pre-oxygenation? why is this helpful
Replaces the nitrogen portion of the Functional residual capacity with oxygen, Acts as a reservoir of oxygen in the lungs which increases the time to desaturation at induction, allows for more time to intubate before animal desaturates
preoxygenate for 3-5 mins
What can you use for induction of a trauma patient?
- Propofol, alfaxalone, ketamine [consider co-induction with midazolam, ketamine, fentanyl]
- Administer slowly to effect [animals with poor cardiac output will have a slower induction time with injectable agents]
- May need very low dose [may be possible to intubate with just premed in very compromised patients!]
- Elevate the head, secure the airway rapidly [remember that in an emergency patients may have a full stomach and increased intrabdominal pressure]
What is important in head trauma cases with induction and intubation?
In head trauma patients ensure adequate depth of anaesthesia before attempting intubation and ensure lidocaine spray has contacted the larynx in cats [coughing causes a sudden increase in ICP]
what can you do differently if you need assess to the mandible or mixilla during surgery?
Trans-mylohyoid or phayngostomy intubation
what are the benefits of using local anaesthesia during surgery?
provides analgesia, reduce sympathetic stimulation intraoperatively, reduces MAC and dose requirements, provides post-operative analgesia.
bupivicaine is longer acting up to 8hours
what are the key aspects of surgery for diagphragmatic hernias?
Keep in sternal for as much of the anaesthetic time as possible, desaturation can occur rapidly when positioned in dorsal recumbency, elevate the thorax, instigate IPPV
How should you ventilate an animal with pneumothorax?
IPPV at low volumes and pressures (don’t want too much pressure in the chest)
and drain to allow reinflation of the lungs and increase tidal volume
How should you ventilate with haemorrhage and hypotention?
IPPV, especially PEEP can exacerbate hypotension by decreasing venous return and cardiac output
therefore IPPV, with light pressure and tolerate some hypercapnia
What are the principles of ventilation in head trama?
- Maintain EtCO2 30-35mmHg if possible and avoid permissive hypercapnia (including in patients with concurrent pulmonary or intrathoracic lesions)
- Hypercapnia and acidosis lead to vasodilation and a potential increase in ICP
- Hypocapnia should also be avoided though as it causes vasoconstriction and reduced perfusion.
[Other considerations: elevate head, avoid jugular catheters, sampling, other forms of compression etc.]
What the A-a gradient be used for?
indicate the origin of hypoxaemia
A - Elevated = gas exchange
A - Normal = ventilation
What are the considerations with temperature and head trauma?
Hypothermia is often a negative prognostic indicator, along with coagulopathy and acidosis
Active cooling in traumatic brain injury reduces cerebral metabolism and blood flow but is controversial in people
However, care with active rewarming
What are the stratergies for managing hypotention in trauma cases while under anaesthetic?
In what cases can you tolerate hypotension?
- Reduce inhalation agent
- Try PIVA if needed
- IVFT boluses
- Consider anticholinergics if bradycardic
- Consider vassopressors (e.g. ephedrine, noradrenaline etc.)
Permissive hypotension in bleeding patients (MAP ~50mmHg)? [NOT in TBI]
