This man is clearly in shock and requires simultaneous assessment and resuscitation.

I would assess him using and A, B, C, D approach to identify the most serious problems first.

He will be managed according to the CCrISP algorithm and IV fluids shall be given with high flow oxygen via a non re-breath mask.

A blood gas would provide information regarding his acid-base balance, electrolytes, Hb and lactate which is a direct indicator of shock.

The most likely cause in this scenario is intra-abdominal sepsis and he may well require a laparotomy. I would seek help from my senior colleagues and prepare this man for surgery once stabilised on the ward. I would also inform ITU of this patient and the potential need for a bed following his operation.

Metabolic acidosis occurs when the kidneys are unable to excrete hydrogen ions or increased levels of lactate thus driving the acid-base equation to the right causing an increased respiratory rate to help remove CO2 and reduce the acidity in the body.

Pre-renal causes: hypovolaemia, sepsis or low cardiac output
Intrinsic renal causes: ATN, hypoxia and hypoperfusion, toxin and drug related nephropathy, hepatorenal and abdominal compartment syndrome.
Post renal causes: bladder or ureteric obstruction or blocked catheter

An ECG should be performed and a second sample should be sent to the lab while treatment for hyperkalaemia is started to ensure the initial result was not haemolysed or anomalous.

Calcium gluconate 10-30mls of 10% solution should be given IV to protect the heart and allow for membrane stabilisation.

10 units of Actrapid should be given in a 100mls of 50% dextrose to help drive the potassium into the cells and this can be additionally helped with a 5 mg salbutamol nebuliser.

When the potassium is driven into the cells it is exchanged for hydrogen ions so it is important to be aware that the patient will become acidotic and sodium bicarbonate should be on standby to overcome this metabolic imbalance.