A 74-year-old lady with a history of ischaemic heart disease and severe congestive cardiac failure is admitted to the ICU with hypotension and presumed sepsis

A17

A 74-year-old lady with a history of ischaemic heart disease

and severe congestive cardiac failure is admitted to the

ICU with hypotension and presumed sepsis. She is sedated

and ventilated in pressure support mode. On examination

she is confused, BP is 85/35mmHg, HR is 115bpm (sinus

tachycardia), SpO2 is 95% on 60% oxygen. Arterial blood

gas analysis shows a lactate of 4.3mmol/L (39mg/dL).

Which is the BEST guide to the need for further intravenous

fluid replacement?

a. Response of oesophageal Doppler to passive leg raising.
b. Insertion of a pulmonary artery catheter and pulmonary artery
occlusion pressure measurement.
c. Titrate fluid resuscitation against repeated blood lactate
measurements.
d. Assess pulse pressure variation.
e. Urine output measurement.


A

This patient may have hypotension secondary to a variety of causes,

including sepsis and decompensated cardiac failure. 

Pulmonary artery 

occlusion pressure has been shown to be a poor predictor of whether a

fluid bolus will cause an increase in cardiac output (i.e. whether the patient

is volume-responsive). 

Blood lactate is a sensitive marker of shock and

falling levels correlate with improved survival.

 However, this will not

distinguish between cardiogenic shock (where inotropes may be required)

and septic shock (requiring fluids and/or vasopressors). 

Pulse pressure

variation of >13% has been shown to accurately predict response to fluid,

but is only reliable in mechanically ventilated patients without spontaneous

respiratory effort. 

Urine output measurement will again not distinguish

between different causes of shock. 

Passive leg raising autotransfuses

about 300ml of blood into the central circulation. 

If stroke volume

increases significantly (>10% as measured by oesophageal Doppler), this

indicates preload-responsiveness. 

An advantage of this technique is that it

is reversible if no improvement is seen, avoiding worsening pulmonary

oedema in the case of cardiogenic shock.