Abstract
After giving an account of the principles of pressure measurement in flowing air and a review of the literature on tracheal catheters, the authors describe the construction, the introduction and the function of their own transtracheal catheter. This is a teflon catheter with several side–ports which is introduced into the cervical trachea by a guide technique. After introduction, the catheter is stiffened by the insertion of 2 steel wires. The catheter was studied in model experiments concerning: a) the ability to measure the static pressure in flowing air, and b) the dynamic accuracy of a recording system built up around the catheter.
The results indicated that the intratracheal pressure sensed in exercising horses well reflected the static pressure, and that the dynamic accuracy of the recording system was good to about 60 Hz. The present technique of recording the intratracheal pressure was used on 122 occasions in 69 exercising horses with only one complication referable to the catheter occurring. The transtracheal route of catheterisation may be superior, as catheters introduced by this route do not appear to influence the function of the pharynx and larynx. In contrast, nasotracheal catheters that traverse the larynx, might interfere with the respiratory function. kw|Keywords|k]upper airway obstruction k]frequency response
Sammanfattning
Författarna redogör för principerna vid tryckmätning i strömmande luft och gör en genomgång av litteraturen över tracheal k atetrar. Konstruktion, införande och funktion av deras egen transtracheal kateter beskrivs. Detta är en teflonkateter med ett flertal sidoöppningar. Den förs in i luftstrupen med hjälp av en guideteknik. Efter införandet förstyvas katetern med två metalltrådar. Katetern har studerats i modellförsök med avseende på:
förmåga att mäta det statiska trycket i strömmande luft, och
den dynamiska exaktheten i ett registreringssystem uppbyggt kring katetern.
Resultaten tyder på att det intratracheal a trycket registrerat hos arbetande hästar väl avspeglar det statiska trycket, och att den dynamiska exaktheten hos registreringssystemet var god upp till c:a 60 Hz. Den beskrivna tekniken for intratracheal tryckmätning användes vid 122 tillfällen på 69 hästar under arbete, med en komplikation som kan hänföras till katetern i endast ett fall. Den trans trachea la metoden för kateterisering synes överlägsen, eftersom en kateter införd med denna metod, i motsats till nasotracheala katetrar, ej tycks påverka funktionen i pharynx och larynx.
Full Text
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Acknowledgments
The authors are very grateful to Ann–Marie Löfgren for performing most of the drawings and to Maud Lide for excellent secretarial work.
References
- Benedict RP. Pressure measurement in moving fluids. In: Benedict RP, editor. Fundamentals of Temperature, Pressure, and Flow Measurements. New York: John Wiley and Sons; 1969. pp. 233–261. [Google Scholar]
- Blake WK. Differential pressure measurement. In: Goldstein RJ, editor. Fluid Mechanics Measurements. Hemisphere Publishing Corporation: Washington; 1983. pp. 61–97. [Google Scholar]
- Cook WR. Proc 27th Ann. Conv. Am. Assoc. Equine Pract. 1981. Some observations on form and function of the equine upper airway in health and disease. Part II. The larynx; pp. 355–391. [Google Scholar]
- Derksen FJ, Stick JA, Scott EA, Robinson NE, Slo–combe RF. Effect of laryngeal hemiplegia and la–ryngoplasty on airway flow mechanics in exercising horses. Amer. J. vet. Res. 1986;47:16–20. [PubMed] [Google Scholar]
- Fry DL. Physiologic recording by modern instruments with particular reference to pressure recording. Physiol. Rev. 1960;40:753–788. doi: 10.1152/physrev.1960.40.4.753. [DOI] [PubMed] [Google Scholar]
- Funkquist B, Holm K, Karlsson A, Kvart C, Mo–lander C, Obel Studies on the intratracheal pressure in the exercising horse. J. vet. Med. 1988;A35:424–441. doi: 10.1111/j.1439-0442.1988.tb00055.x. [DOI] [PubMed] [Google Scholar]
- Holm K, Funkquist B, Obel . Clinical method for evaluation of upper airway function. In: Persson SGB, Lindholm A, Jeffcott LB, editors. Equine Exercise Physiology 3. Davis. Califonia: ICEEP Publications; 1991. pp. 449–456. [Google Scholar]
- Jackson AC, Vinegar A. A technique for measuring frequency response of pressure, volume and flow transducers. J. Appl. Physiol. 1979;47:462–467. doi: 10.1152/jappl.1979.47.2.462. [DOI] [PubMed] [Google Scholar]
- Mangseth G: Evaluation of tracheal pressures in the running horse. Proc. 4th Ann. Meet. Assoc. Equine Sports Med. 1984, 74–80.
- Morris EA, Seeherman HJ: The dynamic evaluation of upper respiratory function in the exercising horse. Proc. 34th Ann. Conv. Am. Assoc. Equine Pract. 1988, 159–165.
- Nielan GJ, Rehder RS, Ducharme NG, Hackett RP. Measurement of tracheal static pressure in exercising horses. Vet. Surg. 1992;21:423–428. doi: 10.1111/j.1532-950X.1992.tb00075.x. [DOI] [PubMed] [Google Scholar]
- Roethlisberger-Holm K. Recording of intratracheal pressure in the horse under field conditions as a method for evaluation of upper airway resistance. J. Vet. Med. 1993;A40:516–524. doi: 10.1111/j.1439-0442.1993.tb00660.x. [DOI] [PubMed] [Google Scholar]
- Roethlisberger-Holm K. Tracheal pressure in horses with signs of dorsal displacement of the soft pe–late. In: Robinson NE, editor. Equine exercise physiology 4. 1995. pp. 70–74. [Google Scholar]
- Seldinger SI. Catheter replacement of the needle in percutaneous arteriography. Acta Radiol. 1953;39:368–376. doi: 10.3109/00016925309136722. [DOI] [PubMed] [Google Scholar]
- Shapiro GG, Krovetz LJ. Damped and undamped frequency responses of underdamped catheter manometer systems. Am. Heart J. 1970;80:226–236. doi: 10.1016/0002-8703(70)90172-9. [DOI] [PubMed] [Google Scholar]
- Williams JW, Pascoe JR, Meagher DM, Hornof WJ. Effects of left recurrent laryngeal neurectomy, prosthetic laryngoplasty, and subtotal arytenoi–dectomy on upper airway pressure during maximal exertion. Vet. Surg. 1990;19:136–141. doi: 10.1111/j.1532-950X.1990.tb01155.x. [DOI] [PubMed] [Google Scholar]