Case in the Spotlight 13: Answers

Venous blood

Ph   7.82 mmHg
pCO2   21  mmHg
pO2   27  mmHg
BE   17
HCO3   35
Lactate  15.7

Na   116
K   2.0
Cl   65
Urea   10
Cr   196 umol/L
Hct   45%
Hb   15.5 g/dL

• Severe metabolic alkalosis – hypokalaemic hypochloraemic
(very high pH, with a high HCO3) 
• Consideration of any compensation with respiratory acidosis (hypoventilation) is not a clinically relevant consideration, however
• the CO2 is low so co-existent respiratory alkalosis is present
• Anion gap = (116+2) – (10+ 75) = 33 = raised anion gap metabolic acidosis -noting raised lactate as most likely cause, consider hypoxia and sepsis as contibutors


Spot diagnosis 1 2016

Severe QT prolongation
This is very likely due to the severe hypokalaemia

Outline the management priorities, including how urgency/prioritisation

The patient needs urgent cardiac monitoring preferable resuscitation area, and urgent potassium replacement

Clinical escalation, getting senior medical and nursing input, +/1 extra resources is warranted

Fluid resuscitation is needed, large bore IV access, probably 2nd IV access.

Normal Saline is a reasonable choice, noting that you will titrate fluid resuscitation to volume status first

The hypokalaemia correction is urgent

The speed of sodium correction is the third consideration

Frequent monitoring of bloods – an arterial line would facilitate monitoring of BP and also frequent blood sampling.

Point of care blood tests will get rapid turnaround of results