A 51-year-old male with a history of cirrhosis secondary to Hepatitis C is admitted for the first time with haematemesis. His gastroscopy is complicated by aspiration. He is admitted to ICU ventilated.
The following results were obtained:
Parameter |
Patient Value |
Adult Normal Range |
FiO2 |
0.4 |
|
pH |
7.16* |
7.35 – 7.45 |
pO2 |
109 mmHg (14.1 kPa) |
|
pCO2 |
29.0 mmHg (3.87 kPa)* |
35.0 – 45.0 (4.60 – 6.00) |
SpO2 |
95% |
|
Bicarbonate |
10.0 mmol/L* |
22.0 – 26.0 |
Base Excess |
-17.0 mmol/L* |
-2.0 – +2.0 |
Lactate |
4.5 mmol/L* |
0.5 – 1.6 |
Sodium |
144 mmol/L |
135 – 145 |
Potassium |
4.4 mmol/L |
3.5 – 5.0 |
Chloride |
114 mmol/L* |
95 – 105 |
Glucose |
11.0 mmol/L* |
3.5 – 6.0 |
Parameter |
Patient Value |
Adult Normal Range |
Urea |
17.0 mmol/L* |
3.0 – 8.0 |
Creatinine |
110 µmol/L* |
45 – 90 |
Albumin |
23 g/L* |
35 – 50 |
Protein |
41 g/L* |
60 – 80 |
Total bilirubin |
56 µmol/L* |
< 26 |
Aspartate transferase |
67 U/L* |
< 35 |
Alanine transferase |
101 U/L* |
< 35 |
Alkaline phosphatase |
78 U/L* |
30 – 110 |
g-Glutamyl transferase |
36 U/L |
< 40 |
Calcium (total) |
2.13 mmol/L |
2.12 – 2.62 |
Interpret these results, giving likely reasons for the abnormalities. (40% marks)
UEs: low HCO3 indicates metabolic acidosis, elevated Urea to Cr ratio likely related to GIT bleed (other causes are dehydration, excessive diuretics, high protein diet, steroids), elevated Cr likely due to kidney injury (likely pre-renal, renal causes possible (including hepatorenal syndrome), post-renal causes less likely).
ABG: There is an increased anion gap metabolic acidosis (20).
The delta ratio is 0.57 indicating a mixed high and a normal anion gap metabolic acidosis. High anion gap component likely secondary to shock from hypovolaemia, possibly sepsis from aspiration. Normal anion gap component may reflect saline resuscitation, renal impairment. There is partial respiratory compensation (expect the CO2 to be 23=1.5xHCO3 + 8), which is likely due to mechanical ventilation. There is an increased Aa gradient, presumably because of the aspiration. The elevated lactate may represent shock, liver impairment or treatment with catecholamines. Mildly elevated glucose presumably a stress response.
LFTS: Low albumin could indicate chronic synthetic liver disease or be due to acute sepsis/SIRS or related to volume expansion with non-albumin fluids. Elevated ALT related to hepatocellular injury most likely Hep C plus/minus hypoperfusion related to the haematemesis. Elevated bilirubin likely related to chronic cirrhosis (pre-hepatic causes are possible (including transfusion), and biliary obstruction is less likely as GGT/ALP not elevated).
This college answer is by far the best biochemistry answer CICM examiners have ever written, and should represent some kind of standard for all future examiners' answers. They will all be measured against it.
Let's start with the gas:
Thus, this is an ABG of a patient who is
As for the biochemistry: