By T. M. Gibson (introduced by J. Ernsting). R.A.F. Institute of Aviation Medicine, Farnborough, Hants
Pipers contend that playing the bagpipes is extremely strenuous. Cases have been experienced by piping teachers of neophytes fainting while trying to play the pipes. Watson (1972) suggested that hypocapnia caused the faintness. He reported expired CO2 tensions (PE. c02) of 13.7—26-6 torr, pulmonary ventilations (VE) of 15-30 1. min-1, peak expiratory pressures of 30-40 torr and respiratory frequency (f) of 30 breaths min-1; 48 1. of air were required to inﬂate the bag in 30 sec. These ﬁgures seemed a little inappropriate and so the experiment has been repeated.
Measurements have been made in one standing subject (an experienced, professional piper) playing a set of pipes ﬁtted with competition (i.e. hardest to blow) reeds. The blowpipe was replaced by a mouth-piece attached to a section of ﬂexible hose containing a pneumotachograph, a pressure-tapping and a mass-spectrometer sample port. Measurements were made of expiratory pressure (VE), peak expiratory ﬂow (f). and end tidal Pco2 (PET. co2) with and without the drones and while playing various sustained notes. Oxygen consumption was estimated from measurements of VE and of mixed PE. 02 and PE. C02.
Inﬂation of the pipes from an empty bag to steady-state playing consistently took 10 sec. and required a volume of 51. Peak ﬂows during inflation averaged 160 1. min-1 on the ﬁrst breath and fell to a steady 60 1. min-1 by the fifth breath. The expiratory pressure required for low notes (about 55 torr) was less than that required for high notes (66 torr). During steady-state playing the pressure in the bag was kept as high as, or higher than, the pressure required to play the high notes, and values up to 73 torr were recorded. The increased intrathoracic pressure during delivery of gas to the bag was maintained for an average total of 36 sec/min. Mean VE was 22.01. (BTPS) min-1 and f averaged 21 breathsmin-1. PET C02 fell to a steady level of 21.3 torr and oxygen consumption was 0.75 1. (s.t.p.d.) min-1.
The oxygen consumption of 0.751. min-1 represents an increase in oxygen uptake by the respiratory and postural muscles over resting values; it is clear therefore that a major factor limiting continuous playing time will be respiratory fatigue. In addition, high intrathoracic pressures combined with lowered PET C02 are likely to produce fainting in inexperienced performers (see Howard, Leathart, Dornhorst & Sharpey-Schafer, 1951). Watson is probably correct in suggesting that experienced pipers have adapted to the respiratory demands of playing the instrument. However, piping may produce greater intrathoracic pressures (and hence cardiovascular strain) than previously recognised.
• The technical assistance given by Dr. J. Ernsting and Mr. W. J. Tonkins is gratefully appreciated.
Howard, P., Leathart, G. L., Dornhorst, A. C. & Sharpey-Schafer, E. P. (1951).Brit. Med. J. no. 4728; pp. 382-384.
Watson, A. W. S. (1972). J. Physiol. 227, 3P-4P.
• This article first appeared in the December 1982 Piping Times.