Cambridge, UK – November 27, 2019 – Directed Systems Ltd today announced U.S. Food and Drug Administration (FDA) 510(k) clearance of Hypotension Decision Assist (HDA)TM, a clinical decision support Software as a Medical Device (SaMD) that is installed upon a medically-rated touch-screen computer.

HDA is indicated to acquire, process and display arterial pressure and other key cardiovascular characteristics of adult patients who are at least eighteen years of age that are undergoing surgery where their arterial pressure is being continuously monitored by a vital-signs monitor. It is indicated for use to assist anesthesia healthcare professionals manage the blood pressure, hemodynamic stability and the cardiovascular system during such surgery.

We are delighted to receive FDA 510(k) clearance of Hypotension Decision Assist (HDA)TM which marks a true milestone for Directed Systems as a business.  Not only does this allow us to now begin marketing and sales of HDA in the United States, but it is tremendous validation of our Product Development to date.”

Mark Leaning, CEO & Founder

The problem of intra-operative hypotension (IOH)

Intra-operative hypotension (IOH) is a common and frequent occurrence in patients undergoing general anesthesia for non-cardiac surgery.  A 2014 study of almost 17,000 anesthetic records revealed that 26% of the surgical patients involved had a peri-operative systolic blood pressure of <80mmHg for >5minutes1

Studies have shown that 30-day mortality was strongly related to time-weighted average intra-operative Mean Arterial Pressure (MAP)2.

The threshold for myocardial injury is a MAP <65mmHg. The threshold for renal injury may be higher, possibly nearer 75mmHg.  A few minutes of a MAP <55mmHg is associated with Acute Kidney Injury and Myocardial Injury and has been demonstrated to increase markedly with prolonged intra-operative hypotension3.

“There does not appear to be any safe duration of a MAP less than 55 mmHg”

Walsh, 2013

About Directed Systems Ltd

Directed Systems Ltd is a fast-moving medical software and data science company based in Cambridge, UK. Our target customers for HDA are the anesthesiologists and hospitals who are concerned about the incidence and cost of post-operative complications of intra-operative hypotension. We develop software that incorporates smart proprietary algorithms to analyze, visualize, predict and interpret real-time physiological signals.

Directed Systems has its US base in Austin, Texas.


  1. Nair et al., “Anesthesia information management sytem-based near real-time decision support to manage intraoperative hypotension and hypertension.” Anesth Analg 2014; 118: 206–214
  2. Mascha EJ, Yang D, Weiss S, Sessler DI. “Intraoperative Mean Arterial Pressure Variability and 30-day Mortality in Patients Having Noncardiac Surgery.” Anesthesiol 2015; 123:79–91
  3. Walsh M, Devereaux PJ, Garg AX, Kurz A, Turan A, Rodseth RN, Cywinski J, Thabane L, Sessler DI. “Relationship between intraoperative mean arterial pressure and clinical outcomes after noncardiac surgery: toward an empirical definition of hypotension.” Anesthesiol 2013; 119: 507–515
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