Following laparotomy for haemoperitoneum, a patient is transferred to ICU.
Blood biochemistry and arterial blood gas analysis on admission to ICU are as follows:
|
Test |
Value |
Normal Range |
|
Sodium* |
147 mmol/L |
135 – 145 |
|
Potassium |
3.6 mmol/L |
3.2 – 4.5 |
|
Chloride* |
124 mmol/L |
100 – 110 |
|
Haemoglobin* |
106 G/L |
115 – 155 |
|
pH |
7.32 |
7.35 – 7.45 |
|
pCO2* |
32.4 mmHg (4.3 kPa) |
35 – 45 (4.6 – 5.9) |
|
pO2* |
63 mmHg (8.4 kPa) |
80 – 110 (10.5 – 14.5) |
|
Bicarbonate* |
16.0 mmol/L |
24 – 32 |
|
Standard Base Excess* |
-9.0 mmol/L |
-2.0 – +2.0 |
a) Describe the acid-base status.
b) What is the likely cause of this disturbance?
c) What is the underlying biochemical mechanism?
a) Describe the acid-base status.
Normal anion gap metabolic acidosis with appropriate respiratory compensation
b) What is the likely cause of this disturbance?
Resuscitation with large volume saline infusion.
c) What is the underlying biochemical mechanism?
ECF dilution by fluid with strong ion difference of zero
This question is identical to Question 6.3 from the first paper of 2013.