Respiratory Failure & Respiratory Acidosis

Question 1

37 year-old patient received a high does of morphine post-operatively → dyspnea. now on 60% O2

How CO2 is transported in the blood? write conversion equation

Answer 1

1. Bicarbonate (70%):
2. Carbaminohemoglobin (20%): .
3. Dissolved CO2 (10%)

𝐇𝟐𝐎 + 𝐂𝑶𝟐 ⇔𝑪𝑨 ⇔ 𝑯𝟐 𝑪𝑶𝟑 ⇔ 𝒊𝒏 𝑹𝑩𝑪 ⇔ 𝑯+ + 𝑯𝑪𝑶𝟑 −

HCO3 - → diffuses out to the plasma
H+ → binds to Hb
Cl- → diffuses into the RBC → to maintain cellular balance

Question 2

Why is bicarbonate normal in Resp acidosis caused by morphine?

Answer 2

Compensation takes time

Question 3

Physiological response to hypercarbia? how does morphine act?

Answer 3

Central acidosis → stimulates central chemoreceptors (medulla) → ++ RR to blow off CO2

Binds to Mu receptors in Respiratory centre

Question 3

Causes of respiratory failure

Question 4

Why is PaO2 now normal in this patient?

Answer 4

Patient is on FiO2 is 0.6 = 60%

Question 5

37 year-old patient received a high does of morphine post-operatively → dyspnea. now on 60% O2

Management?

Answer 5

1. A-E: Oxygen, IVF
2. Stop morphine, Start Naloxone
   
   • Dose: 0.4 -2 mg IV initially and repeat every 2-3 min or/and infusion
   • SE: Nausea, vomiting, sweating, tachycardia,
3. Ventilation
4. ITU for Ventilation and Naloxone infusion
5. Treat underlying cause

Question 6

Indications for ITU admission

Answer 6

1. Resp: Ventilation
2. Renal: hemofiltration
3. Cardiac: monitor COP
4. Neurological: Monitor ICP