1 | 4 ABSTRACTS

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INDUCTION OF PULMONARY VASOSPASM BY HAND IMMERSION IN COIl) WATER IN PATIENTS WITH RAYNAUD ' S PHENOHENON

P,J. Fahey, M.D., W. Barr, H,D., A, Carvey.

Department of HedicJne, Loyola Univers i ty S t r i t c h School of t iedicine, ltaywood, I l l i n o i s 60153

In t roduc t ion : In a previous study we noted acute decreases in the lung d i f f u s i n g capaci ty for carbon monoxide (DLCO) following induct ion of d l g f t a l vase - spasm with cold p res su re s t imulu% and hypothesized tha t t h i s was due to spasm occurtng in tile pulmonary vaseu la tu re s imul taneous ly with the d i g i t a l a r t e r f e s (1). ttowever, we tlad no d i r e c t measurement of p u l - monary vascu la r p re s su re or r e s i s t a n c e to document vasospasm. Changes in DLCO can occur due to changes in tile s ize of the pulmonary membrane (Pm) as well as the volume of blood in t i le pulmonary c a p i l l a r i e s (Ve). If the decrease in DICe was due to spasm in the pulmonary c a p i l l a r i e s we would predict tha t V c should decrease while D m would be unaI tered . The purpose of tiae present study was to measure DLCO~ V c and D m before and following induction of d i g i t a l Raynaud's vasospasm. Decreases in DLCO assoc ia ted with a decrease V c would implicate pulmonary vase - spasm aePnmpanlng d i g i t a l vasospasm. In a subgroup of p a t i e n t s we a l so at tempted to determine If pre- t reatment with n l f ed fp ine could block the acute de- c reases in bl.CO induced by cold p resse r t e s t i n g .

Hethod~: Five heal thy non-smoking laboratory personnel served as c o n t r o l s . The study group con- s i s t e d of nine non-smoking subjects all of whom regu la r ly developed symmetrical d l g l t a t blanching typica l of Raynaud's vasospasm following exposure to cold. l~n:" volumes, exp i ra to ry flow r a t e s and DLCO were measured at base l ine and 60 minutes a f t e r both hands were immersed ill 15=C water for a period of 2 minutes , Determination of V c and D m was performed using tile equation of Roughten where:

1 l ] bl.CO b m OV c

By measuring DLCO us ing two inspi red oxygen con- c e n t r a t t o n s (20Z and 90Z) paired values for DLCO and 0 are obtained. This permits determinat ion of the value for V c and D m us ing the method of Cotes (3). In four s u b j e c t s who demonstrated decreases in DLCO a f t e r cold p r e s s e r s t imulus the study was repeated on a separa te day, however, 30 minutes pr ior to cold p resse r s t imulus 1Omg of n t f e d l p i n e ~ts adminis tered s u b t t n g u a l l y .

Resul t s : Control s u b j e c t s developed erythemea of the d i g i t s following cold p resse r s t imulus but no blanching. All Raynaud's sub jec t s promptly devel - oped discomfort in the hand and d i g i t a l bhmching. Lung volumes and expi ra tory flow ra t e s did not change s i g n i f i c a n t l y in e i t h e r group. Control sub- J e c t s did not show s i g n i f i c a n t changes in DLCO, V e or D m. llowever, each sub jec t with Raynaud's vase- spasm demonstrated s i g n i f i c a n t decreases in DLCO a f t e r 60 minutes (Fig 1) (24.4 z 6.6 vs 19.g z 6.1 ml/min/mmttg p<O.Ol), The acute decrease in ~LCO was due to a s i g n i f i c a n t decrease in Vc (54 ± 20 VS

39 ± 10m], p<.O5) while D m was unchanged 52 ± 17 vs 5I ± 20ml/min). In the four sub jec t s who were t e s ted 45 minutes following 1Omg of subl tngual n i fedp tne , acute decreases in DLCO were again noted, The magnitude of the change was s i m i l a r to t e s t i n g done without n t f e d i p t n e .

Conclusion: The reduct ion in DLCO following cold p resse r s t imulus in p a t i e n t s with Raynaud's phe- nomenon is due to an acute decrease in Vc, c o n s i s - ten t with the development of pulmonary vasospasm due to an acute reduct ion in the s i ze or number of pulmonary c a p i l l a r i e s , Pretreatment with n l f e d ip lne f a i l ed to prevent a s i g n i f i c a n t dec l ine in DLCO which again was assoc ia ted with a decrease in V c. These f ind ings ind ica te the pulmonary v e s s e l s do undergo spasm following cold p resse r t e s t i n g and tha t the decrease in V c p e r s i s t s for at l e a s t 60 minutes, even a f t e r d i g i t a l spasm is no longer evident . ~Hfedipine, a t t h i s dosage, does not pre- vent th~s vasospasm, tlechantsms respons ib le for Raynnud's phenomenon of the lung remain unc lea r .

Tabl e I

Basel ine Post n l f ed tp ine

PLCO (ml/mtn/mmllg) 23.6"-10.6 20.9~9.6 V c (ml) 62"27 43"_12 D m (ml/min/mrallg 39"-19 52±34

40"

= 30- o E

° 2 20-

10,

RAYNAUDS

Pie Post CaM Pff=~of T~t

80"

eo. O ~

~ 4 0 '

2 0 ' Pre POSt

Cold Presser Test

Changes in DLCO and Vc 60 min. following cold presser test.

1. Fahey PJ, Utell HI, Condemf JJ , et a l . Raynaud's Phenomenoll of tile Lung. Am J lied. 19841 76:263-269.

2, Roughton FJW, Fors ter RE. The r e l a t i v e im- portance of d i f f u s i o n and chemical reac t ion r a t e s in determining the ra te of exchange of gases in tile human lung. J Appl Physiol . 1957; 11:290.

3. Cotes JE. Lung Function. BlaekweI1 Scient l£ie Publicat ion, London, England 1975 ~ pages 253-259.