Pre-anaesthesia risk assessment routinely covers cardiac history, airway, and general fitness for surgery — but rarely tests autonomic function directly, even though Cardiac Autonomic Neuropathy (CAN) is an established predictor of perioperative cardiovascular instability. For a patient with undiagnosed CAN, that's a risk factor going into theatre that standard pre-op screening simply doesn't catch.

Why CAN matters specifically at the point of anaesthesia

Anaesthesia itself stresses the autonomic nervous system — induction, positioning changes, and intraoperative haemodynamic shifts all depend on intact autonomic reflexes to maintain stable blood pressure and heart rate. In a patient whose autonomic reflexes are already impaired by CAN, that compensatory capacity is reduced, which is precisely why CAN is linked to a higher risk of intraoperative hypotension and cardiovascular instability under anaesthesia.

Who this matters most for

  • Long-duration diabetics scheduled for elective surgery — the population where CAN prevalence is highest, and where it's least likely to have already been diagnosed.
  • Patients undergoing major or prolonged procedures — longer anaesthesia time means more opportunity for autonomic compensation to be tested.
  • Patients with unexplained intraoperative haemodynamic instability in a prior surgery — a history worth investigating rather than attributing to the anaesthetic alone.

A screening test that fits the pre-op window

Pre-surgical screening has to fit into an already-packed pre-anaesthesia workup, which is where NIBRA-CS®'s Short Test is a practical fit: a single passive 5-minute HRV recording, with no active manoeuvres, BP cuff, Valsalva assembly, or handgrip dynamometer required. That matters clinically too — some pre-op patients may not be well positioned to safely perform the Full Test Battery's active manoeuvres, and the Short Test doesn't require them to.

The Short Test produces a 3-page report on HRV status in 5 minutes plus prep time — short enough to add to a same-day pre-anaesthesia assessment without materially extending it. Standardised, scored HRV output gives the anaesthesia team an objective data point rather than a subjective impression.

An objective input, not a standalone decision

A Short Test result doesn't replace clinical judgement — it adds a data point that pre-anaesthesia risk stratification doesn't currently have access to. A reduced HRV result is a reason to plan for closer intraoperative haemodynamic monitoring, involve senior anaesthesia input, or, where the screen suggests it, follow up with the Full Test Battery for a complete Normal / Early / Definite / Severe CAN classification before the surgery date.

See the Short Test protocol, or enquire for your anaesthesia or surgical department

View Tests Supported → Enquire for Your Institution →