VENTILATOR TIPS & TRICKS

1) HYPOXIA

CAUSE / PROBLEM / TREATMENT
¯ VENTILATION / ¯ TV/RR / ­TV and/or ­RR
LOW FiO2 / Not enough O2! / ­ FiO2
V/Q mismatch / Mainstem bronchus intubation
PTX
PE / Find & treat cause
Diffusion impairment / Emphysema
Fibrosis / Pressure control
Shunt (V/Q = 0) / Alveolar collapse/filling
-  Pneumonia
-  ARDS
-  Contusion/haemorrhage
-  CCF
Intracardiac / PEEP

2) NOT VENTILATING?

1)  Disconnect ventilator

2)  Bag & Mask 100% FiO2

3)  Check Patient

  1. ETT position
  2. Tension PTX
  3. Agitation/sedation issue

4)  Check Tube

  1. Suction
  2. Cuff
  3. THEN à Check ventilator

SPECIAL CIRCUMSTANCES

1) ASTHMA – AUTO-PEEP (BREATH STACKING)

Diagnosis

1)  ¯ Sats

2)  ¯ BP

3)  PTX excluded

4)  Exp flow curves (on snazzy ventilators)

Management:

1)  Disconnect ventilator

2)  Connect BVM BUT DON’T VENTILATE

3)  100% FiO2

4)  Allow to exhale ( may take 1-2 mins

5)  Reconnect when:

  1. Finished exhaling
  2. Sats < 90%

2) CLOSED HEAD INJURY

AVOID

1)  ­ ICP

  1. Heavy sedation +/- paralysis (ie avoid cough/strain, may need pressors to maintain MAP)
  2. Elevate head of bed
  3. AVOID PEEP

2)  HYPOXIA

3)  HYPERCARBIA (AIM CO2 = 35mmHg – ie lower end of normal)

4)  HYPER OR HYPOTENSION

5)  HYPER OR HYPOGLYCAEMIA

VENTILATOR MODES:

CONTROL: CMV, IPPV

Breath delivered despite patient effort

MIXED: SIMV

Breathes if patient not breathing

SPONTANEOUS:

PEEP: (= CPAP when strapped to face) – keeps alveoli open

PRESSURE SUPPORT (PS): » BiPAP (ie CPAP + PS)

PEEP = CPAP

Prevents alveolar collapse \ ­ surface area for gas exchange

¯ V/Q mismatch

¯ Shunt

­ Compliance & ¯ WOB

Contraindications:

­ ICP

Hypotension/hypovolaemia

Broncho-pleural fistula

Unilateral lung disease

Start at 10cmH2O and ¯ in increments of 2cmH2O

PEEP > 10cmH2O à need Swan (to correct LAP for PEEP)

PIP & PLATEAU PRESSURE

PIP (PaW) = pressure in upper airway ie air shooting into ETT/trachea/prox bronchi

Pplat = pressure as breath spread to lungs/alveoli

High PIP’s = unlikely to cause damage

High Pplat = can damage lungs

PROBLEMS:

1)  ­ PIP, normal Pplat

  1. Resistance in upper airway
  2. Eg Bronchospasm

2)  ­ PIP, ­ Pplat

  1. Compliance issue
  2. Pneumonia
  3. CCF/oedema
  4. Atelectasis
  5. Auto PEEP
  6. Pleural effusion
  7. PTX
  8. Abso distension

3)  ¯ PIP

  1. = AIRLEAK

PRESSURE CONTROL VENTILATION

Set pressure rather than set TV

Better for:

1)  ¯Compliance of chest wall

  1. as volutrauma (not barotrauma) may cause PTX
  2. eg Asthma, COAD, Abdo distension

2)  Circuit Leak

  1. PTX
  2. Flail
  3. Child – uncuffed tube

Problem: NO GUARANTEED TIDAL VOLUME

Especially if coughing/splinting

\ can get HYPOXIC QUICKLY

\ CONSTANT MONITORING (ie better done in ICU than ED)