A 22 year old man is brought in one morning after a standby call. He and his friend have been stabbed with the same knife.

He looks pale and sweaty with HR 140 BP 135/86. There is a single 2cm stab wound just below his xiphisternum. He had good air entry bilaterally and normal heart sounds. He was tender around the stab wound and upper abdomen. There was no external haemorrhage. IV access was obtained and ABGs taken.

He was given 1000ml normal saline and a CXR was performed which looked normal.

ABG result (FiO2 0.85)

pH 7.31
pCO2 4.79
pO2 31.7
BE -7.0
Bic 18.9
Lactate 5.7
Hb 14.3