Cold provocation test results from a 1985 survey of hard-rock miners in Ontario.

L. Cold provocation test results from a 1985 survey of hard-rock miners in Ontario. Scand J Work Environ Health 13 (1987) 343-347. A total of 143 miners, 6 ex-miners, and 42 referents from five mines in northern Ontario were examined with a cold provocation test. The skin temperatures, measured by thermocouples at the tips of the fingers and thumbs were recorded at 5-s intervals throughout the immersion in cold water (IO°C) for 10min and during the recovery period. The finger skin temperature was followed until 99 070 recovery had occurred as compared to the starting temperature. For the referents and the vibration-exposed subjects, the results by separate stage of the Taylor-Pelmear scale for hand-arm vibration syndrome werecompared. There werestatistically significant differences in the mean finger temperature at the 50, 75, 90, and 95 0J0 recovery times between stages 0, 0T/O N, and stages I through 3 combined, as well as significant differences between stages I, 2, and 3. The mean temperature at 10min and the mean hyperemia temperature for eight fingers combined were compared between the miners and referents. There were significant differences in the mean temperature at 10 min and in the hyperemia temperature between the referents and miners in stage ~/ON' as well as between the referents and the miners in stages I through 3 combined. For the worst finger (defined as that with the lowest temperature at 10 min) there was an increasing trend towards a lower hyperemia tem perature and delay in recovery time from stage 0 to stages 2 and 3 combined. Comparison of the positive predictive values of the cold provocation test results for the worst finger supports the use of a staging of blanched fingers based on social and work interference as the grade of severity, rather than the use of a blanching index rating .

Reprint requ ests to: Dr P Pelrnear, Ontario Ministry of Labour , Health and Safety Support Services Branch, 400 University Avenue, Toronto, Ontario M7A IT7 , Canada. tric blanket (heated to 45°C) and covered with a wool overblanket except for the arm to be examined. Thermocouples were applied to the tips of the fingers and thumb with surgical tape and velcro straps, and one was placed in the armpit. When the body temperature measured by the armpit thermocouple was constant at 34-36°C, a sphygmomanometer was placed around the wrist and inflated to 30 mmHg (4 kPa) above the systolic blood pressure, and the hand was immersed in cold water. The water was maintained at a constant temperature of 10°C by thermostat control, and the room temperature for the stud y was maintained at 2o-23°C. The skin temperatures, measured by thermocouples, at the tips of the fingers and thumb were recorded at 5-s intervals throughout the immersion for 10 min and during the recovery period . At 5 min of immersion , the pressure cuff was released . At 10 min, the hand was remo ved from the water and gently dried . The velcro straps were removed and replaced by dry ones. The hand was placed at rest in a hor izont al position . The finger skin temperatures recorded on the tracer chart were followed until they were at 1 0J0 of the starting skin temperature . The opp osite hand was then examined in the same way.

Results and discussion
The mean values of the skin temperature measurements of the referents and miners, grouped as stage O+OT/O N an d stages 1-3 of the Tay lor -Pel mear  scale, were compared (table 2). The differences between the gro ups were significa nt for the temperature at IO min of immersion (T ID) and for the temperature at the time of hyperemia (Til) (P < 0.002). In add ition, the differences between the gro ups were significan t (P < 0.002) for the length of the 50, 75, 90, and 95 0J0 recovery times. Likewise, between stages I, 2, an d 3 the re were significant differences fo r T IO an d T u (ta ble 3) and for the 75, 90, and 95 0J0 reco very times (table 3).
During the cold provocation, three distinct skin temperature respo nse curves were ob served which were term ed A , 8, an d C (figure I). The temperature fo r curve typ e A did no t go below II°C . Fo r cur ve type C it went below II°C and rema ined there throughout the cold pro vocation. For curve type B the temperature went below 11 0 bu t progressively rose with or witho ut a hyperemic peak . It can be noted fro m ta ble 4 that curve type A was th e mo st common fo r all th e groups but the mean of T 10 was progressively lower from stag e 0 to stage 2 of the Tay lor-Pelmea r sca le. Curve type C could be fou nd in every group, bu t it was in-  a Ts = ski n tem peratu re at 5 min of co ld provocation, TH=s ki n tem perature at the time of hyperem ia, Tw =skin tem peratu re at 10 min of cold provo catio n. b Tim e need ed for th e sk in te m perature aft er th e cold prov ocation to rec over to 50, 75, 90, and 95 % of th e te m peratu re bef ore t he provo cat ion. e Diff eren ces betw een the group s at T,o and TH wer e sign ifi cant (all P values < 0.0002).
d Diff erences between the gro ups w ere sign ific ant (all P values < 0.002). a Ts = skin te mperature at 5 min of co ld pro voc at io n, TH= skin tem perat ure at the t ime of hyperemi a, Tw = skin tempe ratu re at 10 min of col d provocatio n. b Time needed for the skin tem perature after the co ld provocati on to recov er to 50, 75, 90, and 95 % of th e temp erature before th e prov ocation . C Differen ces were sig nif icant between sta ges 1, 2, and 3 (all P valu es <0.0002). d Differen ces were signi f ic ant between st ages 1, 2, and 3 (all P values <0.005).
dicative of lat ent, as well as act ual , vasospastic disease and was more frequently ass ociated with the exposed subjects.
A finger blan ching ind ex rat ing (1, 3, and 6 for blanc hing of the dista l interphala ngeal, middl e interphalang eal, and metacarpophalangea l joints of the fingers, respectively) was used for all th e miners in stages I through 3 of the Taylor-P elmear scale. This rating , when compared with the stage grading, could not differentiate stage 2 from stage 3. Tab le 5 compares th e mean of the Tfj and T IO of the min ers with different ratings. Both the T IO a nd Tfj decrea sed as the finger blan ching ind ex ratings increased , and significant d ifferences were noted bet ween ratings 0 and 3,0 and 6, and I and 6. Th e recovery times increa sed with the index ratings (table 5) at 75, 90, and 95 It /o Table 4. Mean of the sk in temperatures of the min ers in Taylor-Pelmear sta ges 0, OriON' 1, and 2 of t he hand-arm vibration syndrome and the reference gro up aft er 10 min of cold provocati on (T1O) acco rdi ng to the type of response curve -All digits except the thumbs inc luded. a Type A =temperature did not go below 11' C, type B =temperature went below 11' C but progre ssively rose with or wit hou t a hyperemi c peak, ty pe C =temperature went below 11' C and remained t here.
Tabl e 5. Result s of the cold prov ocati on test of t he mine rs in Taylor-Pelrnear stages 1-3 of the hand-arm vibrati on syndrome accord ing to th eir finger blanchin g inde x rating -All digits except th e t humbs inclu ded.
---- of the met acarpophal angea l j oi nt. b Time needed for t he sk in temperat ure afte r the cold provocati on to recover to 50, 75, 90, and 95 % of the temp erature before the provoca tion .
c T 5 =skin tempe rature aft er 5 min of co.d provocation , TH=sk in tem peratu re at the t ime of hyperem ia, T lO =skin tempe ratu re aft er 10 m in of cold provo catio n. d Diff erences wer e signi ficant bet w een ratings 0-3, 0-6, and 1-6 (all P valu es < 0.05). e Diff erences were signi fica nt bet w een rati ngs 0-3 and between 0-6 (all P values < 0.02).
of skin temperature recovery, and the differences were significant between the 0 and 3 and the 0 and 6 rat ings.
The result s of the cold pro vocat ion test, grouped by the Taylor-Pelmear stage of hand-arm vibration syndr om e and by the finger blanching ind ex rat ing, were fur ther ana lyzed with reference to th e wor st finger, defined as th at with the lowest T lO • Th e mean temperatures for the worst finger ar e compared in ta ble 6 by stage, an d a progressive lower ing of temperat ures for T lO and T fj can be noted by stage . Included in table 6 are reference means for temperatur es by stag e, derived by rounding the figur es to the near est 0.5°C and inco rpor atin g appro pr iate limits to different iate the stages. Ta ble 7 simila rly shows the mean temp eratures and reference mean s for skin temperatur e at the 50 a nd 75 070 recove ry time s. Th e mea n temper atur es a nd reference mean s for the worst finger with respect to the extent of finger blan chin g (ie, th e blan chin g index) were determ ined and are sho wn in table 8, along with the mean skin temperatures fo r th e 50 and 75 % recovery tim es. It can be seen th at there was a progressive decrease in temperature fo r T lO and Tfj, but the increases in recovery time s were less co nsistent. 6 Table 6. Result s for th e " worst" finge r, ie, that with th e low est temp eratu re at 10 min o f col d provoc ation (T lO ), of the m iners (grouped by Taylor  Th e reference means by the Ta ylor -Pelmea r sta ge of the hand -arm vibration syndrome and by the finger blanching ind ex were used to determine the sensitivity and specificity o f th e cold provocation test. The sensitivity refers to th e proportion of individuals with the hand-arm vibratio n synd ro me, according to the Tay- Table 7. Tim e needed afte r co ld pro vo c at ion fo r 50 and 75 % recovery of the skin temperature recorded before t he tes t o f th e miners (gro uped by the Tayl or -Pelmear s tag e of hand -arm vibr ati on synd rome) and the reference group, as we ll as the ref a 0 = no blanch ing , 1 = blanch ing o f t he d is tal interphalangeal jo i nt, 3 = blanc hing of t he m idd le inte rphalangeal joi nt, 6 = blan ch ing of th e m et ac arpo phalangea l joint . b Skin temperature at the tim e of hyp er em ia . C Derived by rounding the figu res to t he neares t 0.5°C and incorpo ratin g appr o pr iat e limits to d iffere nt iate th e vari ous st age s. Table 9. Valid ity of t he col d provo cat ion test by sta ges 1 and 2 + 3 of th e Tayl o r-Pelmear sc ale fo r th e hand -arm vi bra tion syn dro me . Table 10. Val id it y of t he co ld provocat io n tes t by t he finger blanc hin g index ratings 1 and 3 + 6."    table 9 and by finger blanching  index in table 10. The comparisons are made both for the exposed workers and for all the workers combined. It shows that the cold provocation test is sensitive and specific enough to verify vasospastic disease, as well as finger blanching. However, the positive predictive values for grouping by stage (36-46 % for immersion reference temperatures, 42-63 % for recovery times) are somewhat better than grouping by blanching index (26-33 % for immersion reference temperature and 37-54 % for recovery times) .

Conclusions
The cold provocation test, as described and used in this investigation, has proved to be a feasible and practical test for use in field surveys of vibration-exposed workers.
In assessments of the results of a cold provocation test, the THand T IO of the worker's worst finger and the times at 50 and 75 % of skin temperature recovery should be compared with reference means. The test results will help to confirm the diagnosis of Raynaud's phenomenon and the verification of the stage of the hand-arm vibration syndrome. Since the positive predictive value of the cold provocation test is lower with the blanching index, grading the severity of the handarm vibration syndrome by such means as the Taylor-Pelmear scale used in the present study is preferable.