Tuesday, November 12, 2013

1912-2001: Dr. Martin Wright x

If you were a respiratory therapist during the 1960s, 70, 80s and even the 1990s you probably heard of the name:  Wright.  You may not know a first name, or even the person, but you were familiar with his products:  the Wright Respirometer and the Wright Peak Flow Meter.

And even while his products have made their way to the dark side of shelves in the back of supply rooms, or simply faded into oblivion, his product line has been refined and re-introduced into the market by other names, or padded into other products, with their users having little knowledge of where they came from, nor who introduced them to the marketplace for us to use.  

His name is Basil Martin Wright.  He was a bio-engineer who had a flare for inventing things that measured inspiratory and expiratory flow.  The need for such devices developed during the 1950s when improved anesthetics and pain relievers allowed physicians to perform routine surgeries, particularly abdominal surgeries.  

Wright Respirometer
The need developed for a machine that would breathe for patients.  This was one of the main reasons for the invention of the positive pressure ventilators as you can see here.  On these old ventilators there needed to be some mechanism for measuring the volumes of inspiration and expiration, or tidal volumes, of patients.  This is where the Wright Spirometer comes into play.  

Although this is not how Wright came to invent his devices.  In 1949 he joined the Medical Research Council's for pneumoconiosis, a lung disease caused by inhaling mineral dust.  He realized the unit "lacked the mechanisms of monitoring and studying lung capacity of patients.  So it was for this council that, in 1959, he invented the Wright Peak Flow Meter, the first device for measuring peak expiratory flow (PEF).  This made studies of lung function possible and lead to a greater understanding of lung disease." (1, page 11)

Case for Wrights Spirometer
Such devices also allow the physician to assess the progress of the patient over time.  As the patient gets better, the PEF will get higher, and if the patient gets sicker the PEF may become lower.  The first peak flow meters were large and cumbersome, but in 1974 Wright invented a simpler, cheaper, portable device that could easily be used by the patient at home as a tool to monitor the progress of his disease.  I wrote about the history of the peak flow meter in this post  (1, page 11)

Today peak flow meters are made by a variety of manufacturers, are for single patient use, and are easy to use.  Most asthma experts recommend all asthmatics have one at home, and they blow into it every day at the same time, and to write down their highest number.  This number is referred to as the patient's personal best.  Then the patient makes some simple calculations, and as the PEF starts to drop to a certain point, a plan can be devises what to do and whether the doctor should be called, or whether to simply get to the emergency room, or call 911.  I wrote about the peak flow meter in this post.  

Basil Martin Wright 
In 1957 he started working for the National Institute for Medical Research in London, focusing on creating a similar device to allow anesthesiologists to monitor the tital volumes of patients under the power of anesthetics and pain relievers.  This was important because such medicine has the power to knock out the respiratory drive, and measuring tidal volumes is a great way to measure loss of drive to breath.  

The devices were used to help the anesthesiologist know if prolonged assistance with breathing was indicated, or if the patient required assistance with breathing by use of a mechanical ventilator.  The device was ultimately used by respiratory therapists to monitor the tidal volumes on patients with neuromuscular disorders, or to monitor the progress or regression of patients on mechanical ventilation.  We used to use the Wrights Respirometer daily as part of our weaning screen.  Today the measurements are made by the microprocessor on the ventilator.  

  1. World Almanac Library, "Cutting Edge Medicine:  Machines in Medicine," 2007, Arcturus Publishing Limited, page 11

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