Cases in Shock: Choosing Inotropes and Vasopressors

How do we choose the right pressor in shock? Below is a brief discussion of pressors and their properties as well as 4 cases, where we choose the pressor to use, with reasoning.

If I were to use one general guide, it is, that unless we need to increase the heart rate, then NorAdrenaline, can be used in nearly all cases. 

Below are 4 cases to think about. Try them and then scroll down and read on the properties of all these medications.

CASE 1

A 68 yo male is brought to your emergency department in what appears to be septic shock. He has had a recent urine infection. Over the last 24 hours he has become quite febrile and lethargic according to his wife. This morning he felt unwell and felt like he was going to collapse each time he tried to get out of bed.

On arrival he is alert and oriented. He feels unwell. His vitals are as follows:

• Temperature 38.9
• Heart Rate 115 bpm
• Blood Pressure 65/42
• Sats 96% on room air.

The ambulance have given him one litre of Normal Saline and he is on his second Litre.

You make the diagnosis of Septic Shock most likely due to urinary cause and immediately give antibiotics. The second litre of fluids is now in, with no change in blood pressure.. 

Our Approach:

Given that there is no issue with heart rate at the moment, isoprenaline can be removed. We can also assume no cardiac dysfunction, so we can remove inodilators. This leaves us with:

• Adrenaline
• Noradrenaline
• Vassopressin

The drug of choice to start with is NorAdrenaline. Vasopressin may also be used.

CASE 2

In this case we have exactly the same patient as in case 1 with urosepsis, however, the patient has an added history of atrial fibrillation for which he is on Sotalol. At presentation the patient has a heart rate of 28 beats per minute, and it is a junctional rhythm. He also has acute renal failure and potassium of 7.8mmol/l.

How would you treat this patient’s blood pressure and heart rate now?

This was the case of Septic Shock resulting in acute renal failure, which decreased clearance of Sotalol and resulted in the bradycardia.

Our Approach: A first approach may be to start with isoprenaline and see if there is a rapid change in heart rate and thus blood pressure. If improvement in the heart rate occurs, then Noradrenaline may be added if further blood pressure support is needed. An alternative is to simply commence Adrenaline, which will improve both the heart rate and the blood pressure. Beware in the ischaemic patient.

CASE 3

A 65 yo male is brought in by ambulance. He has had chest pain for the previous 3 hours.He is diaphoretic and looks unwell. His BP is 71/50 and he is speaking in single words, with saturations of 90% on a non-rebreather. His chest examination has widespread crepitations.

He has no relevant past medical history.

Hi ECG is shown below:

A probable LAD occlusion is diagnosed and that the patient is in cardiogenic shock. Your hospital doesn’t have a Cath lab and so you decide to thrombolyse. However, you also need to sort out the cardiac failure and the blood pressure.

How would you treat this patients’s cardiogenic shock?

Our Approach: GTN is not an option for managing the ischaemia, due to the cariogenic shock. The patient is placed on CPAP to assist with breathing. The optimal blood pressure management for this patient would have been to start NorAdrenaline and then we could add Dobutamine if needed. Milrinone may be a substitute in patients with known poor ejection fraction ie., known significant heart failure.

CASE 4

A 68 yo patient has been sent to the ED from...