Lecture 5

Question 1

Reasons for intubation?

Answer 1

1. MAINTAIN patent upper airway
2. PROTECT lower resp tract
3. TRACHEOBRONCHIAL TOILET (enable suctioning)
4. SUPPORT ventilation (if pt sedated/paralysed/resp mm’s need a rest)

Question 2

Side effects of ventilation

Answer 2

D.A.I.T.S

1. D - deadspace increased
2. A - airway resistance (tube longer+narrower)
3. I - infection (higher risk of nosocomial pneumonia)
4. T - trauma (foreign body being inserted (stenosis/fistula)
5. S - secretion movement impaired (this also increases airway resistance; occurs bc can’t expectorate sputum; can’t generate cough d/t open glottis)

Question 3

Pulmonary Effects of Mech Ventilation

Answer 3

1. Reduced compliance in lung (d/t monotonous breathing -therefore less sighs - less stretch - less surfactant
2. Reduced FRC - body position; address with CPAP/PEEP to recruit more alveoli - in mech ventilated - air goes anteriorly (path of least resistance) to non dependent; in normal awake pts - air goes posteriorly to dependent regions
3. Barotrauma (damage d/t pressure; shearing forces from opening and closing alveoli)
4. Volutrauma (damage d/t volume
5. O2 toxicity

Question 4

Why is CPAP used in mech ventilated pts?

Answer 4

To increase the alveoli recruited/address SA loss/reduced FRC

Question 5

Cardiovascular effects of mech ventilation

Answer 5

SPONTANEOUS breathing - the sucking in effect increases venous return

POSITIVE PRESSURE breathing - the positive pressure squeezes the the venous channels and reduces venous return - therefore reduces BP and Q

Question 6

Respiratory effects of mech ventilation

Answer 6

SIGNIFICANT when >48hrs of mech ventilation

• dec diaphragm strength
• dec resp mm endurance
• mm deconditioning

When < 48 hrs:

• rest and repair mm’s
• normalisation of ABGs

Question 7

ICU - effects on other systems? MS, CVS, psycho

Answer 7

MS - deconditioning (mm wasting, bone demineralization, joint stiffening)
CVS - reduced BV, Hb
Psycho - sleep deprivation, anxiety

Question 8

How can physiotherapy techniques minimize the complications of ventilation?

Answer 8

• frequently change position
• encourage spontaneous breathing/coughing
• early rehab

Question 9

What are the BENEFITS of mechanical ventilation?

Answer 9

• reduces the work of breathing
• optimises gas exchange
• avoids respiratory complications
• hastens lung recovery