Diagnosis of vascular injuries caused by hand-transmitted vibration

Objective

For a reliable objective diagnosis of vascular injuries in hand-arm vibration syndrome (HAVS), the standardized cold provocation tests—finger skin temperature measurement during hand(s) immersion in cold water (FST test) and finger systolic blood pressure measurement during local cold exposure (FSBP test)—are widely used. In recent years there is a growing controversy regarding the diagnostic value of these tests. The aim of this study was to describe particularly the diagnostic performance of FST and FSBP tests, and also to focus on the problems and uncertainties regarding the test conditions and results, in the laboratory diagnosis of vascular injuries caused by hand-transmitted vibration.

Method

A review of pertinent published English- and Japanese-language articles and conference proceedings (between 1976 and 2006) was conducted.

Results

From the reports with regard to diagnostic significance of the FSBP test, it seems to be an important laboratory test for diagnosing vibration-induced white finger (VWF). On the other hand, despite a large number of research studies with the FST test, there is a lack of data for the standardized FST test, which can confirm the value of it in diagnosing VWF. Moreover, there is no agreement on effective parameter/s to quantify and compare the responses in FST induced by immersion in cold water. While assessing and staging vascular injuries in HAVS, inquiry regarding finger coldness appears to be useful.

Conclusions

As there is no single test with satisfactory diagnostic ability for VWF, at present it is reasonable to use the cold provocation tests as a part of the comprehensive approach to evaluate HAVS patients. In addition to the objective methods, the index of finger coldness may be useful while diagnosing the vascular component of HAVS.

     

Effects of waterproof covering on hand immersion tests using water at 10°C, 12°C and 15°C for diagnosis of hand–arm vibration syndrome

Objectives: To compare effects of waterproof covering on finger skin temperature (FST) and subjective hand pain during immersion tests using cold water at 10°C, 12°C and 15°C. In the (Draft International Standard) of the International Organization for Standardization (ISO/DIS 14835-1), a water temperature of 12°C and use of water covering are proposed. Methods: Six healthy male subjects took part in the immersion tests and immersed both hands into water at 10°C, 12°C and 15°C for 5 min, repeatedly, with waterproof covering (polyethylene gloves) or without (bare hands). The FST data from middle fingers and subjective pain scores for hand pain were analyzed. Furthermore, the test with water at 12°C was repeated to assess the repeatability of the test. Results: The glove and water temperature factors for FST were significant at every minute from 1 min during immersion up to 2 min after recovery, showing higher values for waterproof covering than for bare hands and showing lowest values for water temperature of 10°C and highest for 15°C. The glove and water temperature factors for subjective pain score were significant at the 1-min and 2-min points during immersion, showing lower scores for waterproof covering than for bare hands and showing highest scores for water temperature of 10°C and lowest for 15°C. The results of the first and second tests using water of 12°C showed no systematic difference in FST and hand pain between the tests, with a few exceptions. Conclusions: Subjective pain during the cold immersion test with polyethylene gloves and water at 12°C can be reduced, while the differences in FST between water temperatures of 10°C and 12°C were small or not apparent at some points during immersion and recovery. The test also seems to be suitable for repeatability. Further investigation on hand–arm vibration syndrome (HAVS) patients to validate the use of the immersion test with gloves to obtain sufficient data for diagnostic value is required.     

The diagnostic value of finger systolic blood pressure and cold-provocation testing for the vascular component of hand-arm vibration syndrome in health surveillance

BACKGROUND: Hand-arm vibration syndrome (HAVS) is a complex condition with vascular, sensorineural and musculoskeletal components. A number of quantitative tests have been used for assisting in the diagnosis of HAVS and grading disease severity. AIMS: To investigate and compare the diagnostic value of finger systolic blood pressure (FSBP) and rewarming of finger skin temperature (FST) following cold-provocation testing, in the assessment of vascular HAVS. METHODS: Twenty-four individuals with vascular HAVS (Stockholm Workshop stage 2 or 3V) and 22 control subjects underwent FSBP measurements at 30, 15 and 10 degrees C and monitoring of FST following immersion of the hands in water at 15 degrees C for 5 min. RESULTS: There was a significant reduction in median FSBP% in the vascular HAVS group in the change in FSBP from 30 to 15 degrees C adjusted for brachial blood pressure (FSBPC%). There was no difference in the median time for FST to rewarm by 4 degrees C between HAVS cases and controls. The sensitivity and specificity of FSBP to discriminate between the groups varied between 44 and 61% and 91 and 95%, respectively. The sensitivity and specificity for the time for FST to rewarm by 4 degrees C were 71 and 77%. CONCLUSIONS: There is little evidence that the described form of finger rewarming after cold-provocation testing is a useful diagnostic test for vascular HAVS, although it may have some moderate influence in ruling out vascular problems. Based on our data, the FSBP may also have limited use in confirming a positive diagnosis of vibration-induced vascular problems. The higher specificity of the FSBP test suggests it may have some value in ruling out the vascular component of HAVS. The data from this study do not confirm the diagnostic power of FSBP for the vascular component of HAVS reported by a few other investigators.     

Cold-stress tests involving finger skin temperature measurement for evaluation of vascular disorders in hand-arm vibration syndrome: review of the literature

Cold-stress tests are used for evaluating vascular disorders in the hand-arm vibration syndrome, and the value of such tests based on finger skin temperature measurement has been investigated. However, there is a wide difference in the test conditions among countries and researchers. Standardization of the cold-stress tests is currently under discussion within the International Organization for Standardization. We reviewed various aspects of the cold-stress tests involving finger skin temperature measurement, including water temperature, hand immersion time and other test conditions, and evaluated their diagnostic significance. Water temperature varied from 0 degrees C to 15 degrees C and hand immersion time varied from 0.5 min to 20 min. The cold-stress tests are associated with relatively severe suffering, thus, higher temperature of cold water and shorter time of immersion are desirable. To date, however, there has not been sufficient data indicating diagnostic value in a test method involving cold water at around 15 degrees C. Diagnostic value is also influenced by other test conditions, such as room temperature, season, use of ischemia during immersion. For standardization of the cold-stress test involving finger skin temperature measurement, these factors must be considered together with water temperature and immersion time.     

Significance of finger coldness in hand-arm vibration syndrome

Objectives To evaluate the relationship between subjective symptoms of coldness in fingers and peripheral circulation in patients with hand-arm vibration syndrome (HAVS). Methods Thirty-five male patients confirmed to have HAVS as an occupational disease took part in this study. Their mean age was 62 years (SD 5) and all were chain-saw operators exposed to vibration for an average of 25 years. Their annual health examination included the history of their daily habits (smoking, drinking, and therapeutic exercise), report of subjective symptoms such as coldness, numbness and tingling in the fingers, and a physical examination; laboratory tests consisted of skin temperature measurement, and pain and vibration perception under conditions of cold provocation. A frequently used method of cold provocation, immersion of the left hand up to the wrist in water of 10°C for 10 min, was used. Results Finger coldness was classified into 3 groups according to its severity: mild group (n=8), moderate group (n=17) and severe group (n=10). There was no significant difference in age or occupational background between the groups. A significant association was found between finger coldness and prevalence of Raynaud's pheno menon (p<001, χ²). The mean skin temperature was significantly lower with the severity of finger coldness (ANOVA, p<0.05). In the cold provocation test, there was no significant difference between skin temperature and coldness at 5 min and 10 min after immersion, though a difference was observed immediately after immersion. No significant difference was observed in the relationship between finger coldness and vibrotactile threshold before, during or after the cold provocation test. Conclusions The severity of coldness in the fingers is significantly related to skin temperature. The severity of finger coldness reflects the extent of peripheral circulatory vasoconstriction. Coldness in the fingers may be a good warning of potential problems in peripheral, circulatory function.     

Influence of waterproof covering on finger skin temperature and hand pain during immersion test for diagnosing hand-arm vibration syndrome

The purpose of this study was to examine the influence of waterproof covering on finger skin temperature (FST) and hand pain during immersion test for diagnosing hand-arm vibration syndrome complying with the proposal of the International Organization for Standardization (ISO/ CD14835-1, 2001) for measurement procedure. Six healthy male subjects took part in the immersion tests and immersed their both hands into water at 12 degrees C for 5 min, repeatedly with two types of waterproof covering (polyethylene and natural rubber gloves) or without hand covering (bare hands) during immersion. The FST data from middle fingers and subjective pain scores for hand pain were analyzed. Statistically significant differences in FST among three conditions were observed showing the highest FST with natural rubber gloves, followed by the FST with polyethylene gloves and the lowest with bare hands. Significant differences in pain score among three conditions were observed during immersion showing the lowest pain score with natural rubber gloves, followed by the pain score with polyethylene gloves and the highest with bare hands. Immersion test with polyethylene gloves instead of bare hands during immersion seems to be suitable for reducing subject suffering.     

A minireview of studies conducted in Japan using finger-skin temperature during cold-stress tests for the diagnosis of hand-arm vibration syndrome

For the diagnosis of the hand-arm vibration syndrome, cold-stress tests using different water temperatures and periods of hand immersion have been investigated in Europe, North America, and Japan. In recent years, peripheral circulation and sensory tests, including finger-skin temperature measurement involving immersion of one hand in cold water at 10 °C for 10 min, have been widely accepted in Japan. On the other hand, standardization of the vascular assessment method is under discussion at the International Organization of Standardization. We reviewed research findings from Japan concerning finger-skin temperature measurement during the cold-stress test, especially factors influencing the test results and the diagnostic significance. For establishment of the cold-stress test for epidemiology studies of the hand-arm vibration syndrome, standardization of the environmental factors influencing the test results and reporting of its sensitivity and specificity are needed. Received: 2 July 1998 / Accepted: 17 January 1999     

Factors influencing autonomic nervous function during cold-water immersion test in patients with hand–arm vibration syndrome

OBJECTIVES: Factors influencing autonomic nervous function in patients with hand-arm vibration syndrome (HAVS) in response to cold-water immersion test with different water temperatures and immersion times were investigated in the summer and winter seasons. METHODS: Fourteen HAVS patients with vibration-induced white finger (VWF) and 14 healthy control subjects individually age-matched to the patients consented in writing and participated in this study. Patients and controls immersed their left hands in water at 10 degrees C for 10 min and at 15 degrees C for 3 min in summer and in winter in a room with temperature maintained at 21+/-1 degrees C. Electrocardiographic (ECG) data were recorded during the test period and the R-R intervals were analyzed with a fast Fourier transformation (FFT) program. Percentage of very low frequency (VLF%; indicator of both sympathetic and parasympathetic nervous function, and function of rennin-angiotensin system), low frequency (LF%; indicator of both sympathetic and parasympathetic nervous function), high frequency (HF%; indicator of parasympathetic nervous function), and LF/HF ratio (indicator of sympathetic nervous function) were calculated. The results by three-way analysis of variance (ANOVA) were reported elsewhere. In the present study, repeated measures ANOVA was used to re-analyze the factors of data measurement time (time factor) and group (group factor), and their interaction for each test method (water at 10 degrees C for 10-min immersion time; water at 15 degrees C for 3-min immersion time) in summer and winter. RESULTS: The HF% of HAVS patients tended to be lower than that of healthy controls throughout the cold-water immersion tests except for during tests involving water at 10 degrees C for 10-min immersion in summer. The group factor for HF% was statistically significant with an exception during the test involving water at 10 degrees C and 10-min immersion time in summer. The time factor for HF% was statistically significant with an exception during the test involving water at 15 degrees C and 3-min immersion time in winter. CONCLUSIONS: The findings of the present study indicated lower cardiac parasympathetic activity in HAVS patients than in healthy controls, especially in winter. The response of the autonomic nervous system to cold stimulation was to some extent more clearly observed during the immersion test with water at 10 degrees C and 10-min immersion time than during the immersion test with water at 15 degrees C and 3-min immersion time. The results revealed by three-way analysis in a previous study were similar to those in the present study with data analysis by repeated measures ANOVA.     

Diagnostic performance of cold provocation test with hands immersion in water at 10°C for 5 min evaluated in vibration-induced white finger patients and matched controls

Purpose  

This study aimed to explore the diagnostic ability of the cold provocation test with hands immersion in water at 10°C for 5 min in diagnosing vibration-induced white finger (VWF).     

Laser Doppler imaging of skin blood flow for assessing peripheral vascular impairment in hand-arm vibration syndrome

The objective of this study was to evaluate the usefulness of laser Doppler imaging (LDPI) of the skin blood flow for assessing peripheral vascular impairment in the hand-arm vibration syndrome (HAVS). The subjects were 46 male patients with HAVS, aged 50 to 69 yr, and 31 healthy male volunteers of similar age as controls. A cold provocation test was carried out by immersing a subject's hand on his more severely affected side into cold water at a temperature of 10 degrees C for 10 min. Repeated image scanning of skin blood flow of the index, middle, and ring fingers was performed every 2 min before, during, and after the cold water immersion using a PMI-II laser Doppler perfusion imager. The mean blood perfusion values in the distal phalanx area of the fingers were calculated on each image. The patients suffering from vibration-induced white finger (VWF, n=20) demonstrated significantly lower skin blood perfusion at each interval of the test as compared with those without VWF (n=26) and the controls (p<0.01, ANOVA). The blood perfusions in the HAVS patients were associated with the severity of the symptoms as classified by the Stockholm Workshop scale for vascular staging. When a subject was considered to be positive if any of the tested fingers showing a decreased blood perfusion and/or a delayed recovery pattern, the sensitivity was 80.0%, and the specificity was 84.6% and 93.5% for patients without VWF and the controls, respectively. These results suggest that the LDPI technique could provide detailed and accurate information that may help detect the existence of impaired vascular regulation to cold exposure in the fingers of workers exposed to hand-transmitted vibration.     

Interpretation of the finger skin temperature response to cold provocation

Objectives: To compare alternative methods of interpreting the response of finger skin temperature (FST) to cold provocation for the detection of the abnormal cold response observed in vibration-induced white finger (VWF). Method: The FST response to cold provocation was measured in 36 male subjects: 12 office workers, 12 manual workers and 12 manual workers with symptoms of VWF. The FSTs were monitored continuously on the distal phalanges of all five fingers of a test hand for 2 min before, for 5 min during, and for 10 min following, immersion of the test hand in water at 15 °C. Of the fingers investigated, 147 were reported not to exhibit blanching and 33 were reported to exhibit blanching. Twenty-one alternative methods of interpreting the response of FSTs to cold provocation were assessed. These were grouped as: (1) areas above the response profile (i.e. the area above the curve showing the FSTs as a function of time during cooling and recovery), (2) areas below the response profile, (3) absolute temperatures during and following cold provocation, (4) percentage differences in FSTs, (5) the times taken for FSTs to rise by specified amounts and (6) rates of change of FSTs. Differences in the response to cooling between those fingers reported to blanch and the fingers not reported to blanch were tested, and receiver operating characteristics (ROCs) were used to compare the sensitivity and specificity of the various measures to symptoms of VWF. Results: The areas above the response profile, areas below the response profile, percentage FSTs, absolute FSTs and rates of change of FSTs tended to discriminate between healthy and unhealthy subjects on a group basis. However, some of these methods of interpreting the FST response to cold provocation did not show a high sensitivity or specificity to vascular dysfunction on individual fingers. The area above the response profile, the percentage of initial temperature at the fifth minute of recovery and the maximum temperature during the 10-min recovery period, were found to show the highest sensitivity and specificity to symptoms of vascular dysfunction. Conclusions: The method chosen to interpret the FST response to cold provocation affects the ability of the test to detect an abnormal cold response. The area above the response profile, the percentage of initial temperature at the fifth minute of recovery and the maximum temperature achieved during a 10-min recovery period appear to be the most suitable measures for monitoring vascular function in workers exposed to hand-transmitted vibration. It is suggested that the FST response to cold provocation should be interpreted with respect to the state of initial blood flow. Received: 12 June 2000 / Accepted: 28 December 2000     

First experiences with DIN ISO 14835-1 in the context of vibration-induced white finger disease

Objectives: In order to establish an international standard of cold provocation test in the assessment of vibration-induced white finger (VWF) disease, an ISO-working group tentatively created the DIN ISO 14835-1. Based on this new standard, previously existing testing conditions had to be modified. Since a comparison of current and previous evaluation procedures is necessary for both the individual assessment and the performance of metaanalyses, the revision and validation of criteria for the examination of the cold provocation tests are appropriate and necessary. Methods: Twenty-one individuals suffering from VWF disease whose disorder was accepted as an occupational disease underwent the cold provocation test on two successive days following a 2- and a 5-min-long exposure to the cold. As a benchmark for classification as ‘normal’ or ‘pathological’, the 15-min mark after a 2-min-long exposure was chosen. A skin temperature of 28°C was selected for discrimination between ‘non-pathological’ (at least 28°C) and ‘pathological’ test results. Results: It could be shown, that exposures to cold water (12°C) over 2 and 5 min lead to similar rewarming profiles, who differ in median systematically by 1°C. A modification of the former classification rule should be considered. After a 5 min exposure, the classification criterion can be based on the temperature assessments measured after 20 min; alternatively the cut point can be reduced from 28 to 27°C while maintaining the previous assessment time of t=15 min. Conclusions: The shown results represent the first attempt of modifying the previous classification criteria of the cold provocation test within the scope of the VWF disease. In view of the described problems of the study design there is no doubt that continuing modifications and their validation on the base of larger collectives groups are necessary.     

Studies of the propriety of the items adopted for the special health examination of vibration hazards at present (author's transl)

Skin temperature, vibratory sense, nail press test and pain sense are customarily used as the items in the special health examination for finding vibration hazards at present. These items are measured under the condition of room temperature at 20 to 23 degrees c and after 10-minute immersion in cold water at 5 degrees C or 10 degrees C. In this report, the propriety of these items was investigated on the basis of measurements in 274 healthy chain saw operators and 294 healthy bush cutter operators. The 10-minute immersion test in cold water at 10 degrees C was adopted in this experiment. The results obtained are as follows: Skin temperatures of the chain saw and bush cutter operators did not show any significant difference by age under the condition at the room temperature, but the recovery in the subjects in the twenties was faster than in the other. Skin temperatures at the 10th minute after the 10-minute immersion test in cold water at 10 degrees C showed very wide deviations among the subjects. Vibratory senses of the aged subjects markedly lowered in comparison with those of the younger subjects. Recovery of vibratory sense after the immersion in cold water showed a tendency which is faster than that of the skin temperature. Correlation between the skin temperature and the vibratory sense at the 10th minute after the immersion was statistically significant. Most of the subjects showed the recovery time within 2 sec with the nail press test under the condition of the room temperature and at the 10th minute after the immersion. Above 95% of subjects complained pain sense with one gram weight at the measurement under the all conditions except immediately after the 10-minute immersion test. From the above results, it should be considered that the value of these measurement may be dominated by the age of the subjects and that the immersion test in cold water to the tests of vibratory sense and pain sense may not have important role in the diagnosis of vibration hazards.     

The analysis of sensitivity, specificity, positive predictive value and negative predictive value of cold provocation thermography in the objective diagnosis of the hand-arm vibration syndrome

The diagnosis of digital artery vasospasm in the hand-arm vibration syndrome (HAVS) is clinically based, and the need for an accurate objective test to support the diagnosis has been highlighted. This study aims to analyse the potential of cold provocation thermography (CPT) to fulfill this role. CPT was performed on two groups of subjects: 10 controls and 21 patients with Raynaud's phenomenon (RP) secondary to HAVS. After taking a pre-cooling image, patients donned latex gloves and immersed their hands in water at a temperature of 5 degrees C for 1 min. The patients removed their hands from the water and discarded the gloves, and further images were taken every 30 s for 10 min. On each image, the temperatures of the tip and base were analysed for each digit. The sensitivity, specificity, positive and negative predictive values for fingertip temperatures only, fingertip and fingerbase temperatures combined, and fingertip temperature, fingerbase temperature and temperature gradient combined were determined. Patients with RP secondary to HAVS demonstrated significantly lower finger tip and base temperatures and lower digital temperature gradients at all time intervals when compared with controls (P < 0.01, Student's t-test). CPT has good sensitivity, specificity, positive predictive value and negative predictive value; it strongly supports the clinical diagnosis of digital vasospasm.     

Cold-provocation testing for the vascular component of hand-arm vibration syndrome in health surveillance

The aim was to investigate whether the use of infra-red thermography (I-R) and measurement of temperature gradients along the finger could improve the diagnostic accuracy of cold-provocation testing (15 degrees C for 5 min) in vascular hand-arm vibration syndrome (HAVS). Twenty-one controls and 33 individuals with stages 2/3V HAVS were studied. The standard measurement of time to rewarm by 4 degrees C (T4 degrees C) and temperature gradients between the finger tip, base and middle (measured using I-R) were calculated. Receiver Operating Characteristics (ROC) analysis to distinguish between the two groups revealed that for T4 degrees C the area under the ROC curve was not statistically significantly different from 0.5 (0.64 95% confidence interval 0.49-0.76). The difference between the tip and middle portion of the finger during the sixth minute of recovery was the most promising gradient with an area of 0.76 (95% confidence interval 0.62-0.87), and sensitivity and specificity of 57.6% and 85.7% respectively. However, this was not significantly different from that for the time to rewarm by 4 degrees C. In conclusion, the cold-provocation test used in this study does not appear to discriminate between individuals with stage 2/3V HAVS and controls and this is not improved by the measurement of temperature gradients along the fingers using I-R.     

Normative data for vascular and neurological tests of the hand-arm vibration syndrome

OBJECTIVES: To assist occupational health professionals to interpret the results of standardised tests for components of the hand-arm vibration syndrome by presenting data for healthy subjects and identifying the effects of some of the confounding variables. METHOD: Thermal thresholds, vibrotactile thresholds, the finger skin temperature (FST) response to cold provocation and percentage finger systolic blood pressures (%FSBP) were measured by standardised procedures. Normative data were obtained for healthy men of working age (17-62 years) during 237 experimental sessions encompassing ten different studies. Hot thermal thresholds and cold thermal thresholds were assessed independently with 38 subjects; 152 measurements of both hot and cold thresholds were made. Vibrotactile thresholds were measured at several locations on 81 subjects, giving a total of 216 measurements at 125 Hz and at 31.5 Hz. The FST response to cold provocation at 15 degrees C was monitored by thermocouples throughout a 2-min settling period, a 5-min immersion period and a 10-min recovery period. A total of 302 measurements was made on 70 subjects. The %FSBPs were measured in four test fingers and one reference finger by strain-gauge plethysmography. Measurements were made on 97 subjects. A total of 351 measurements was made at 15 degrees C, with 341 measurements at 10 degrees C. RESULTS: Normative data and some example normal limits are presented from the current data set and from data presented in other studies. Age was found to influence thermal thresholds, vibrotactile thresholds and the FST response to cold provocation; older subjects exhibited deteriorated vascular and neurological function. Room temperature was found to influence %FSBPs and the FST response to cold provocation; warmer environments resulted in improved vascular response to cold. Outdoor temperature had a small effect on the FST response to cold provocation and on the vibrotactile thresholds. Thermal thresholds showed some influence of smoking habits and of the FST measured prior to testing. For all four tests, any differences between measurement locations were small and there were no differences between left-handed and right-handed subjects. CONCLUSIONS: The current data can assist occupational health professionals to interpret the results of the standardised tests. Comparison with the current data is considered valid for men of working age. Age and room temperature should be recognised as being capable of causing changes in neurological and vascular function.     

A critique of a UK standardized test of finger rewarming after cold provocation in the diagnosis and staging of hand-arm vibration syndrome

BACKGROUND: Accurate diagnosis and staging of hand-arm vibration syndrome (HAVS) is important in health surveillance of vibration-exposed workers and the substantial number of related medico-legal cases. The measurement of the rewarming rate of fingers after cold provocation to the hands (CPT) has been suggested as a useful test in diagnosing HAVS. AIM: To investigate the diagnostic value of a standardized version of the CPT test using a 15 degrees C cold challenge for 5 min applied in the recent compensation assessment of UK miners. METHODS: Analysis of a subset of UK miners assessed at our unit, together with data from a small repeatability study of the standardized CPT in normal subjects. RESULTS: Rewarming time in the CPT was significantly lower in those subjects classified as vascular Stockholm stage 0 compared with Stockholm stages 1-3 combined, but did not discriminate between the stages of abnormality. Using the suggested cut-off in the CPT test, the sensitivity and specificity were calculated as 43 and 78%, respectively. Receiver operator characteristic analysis suggested that the rewarming time of highest accuracy gave a sensitivity of 66% and specificity of 59%. In 10 miners who reported unilateral hand blanching, there was no significant difference in CPT measurements between blanching and non-blanching hands. Repeat CPT measurements in normal subjects suggested mean differences of 52 and 107 s for each hand, and the Bland-Altman coefficient of repeatability was approximately 600 s for all fingers. CONCLUSION: Single application of this standardized CPT test may have limited value in diagnosing the vascular component of HAVS in an individual.     

Finger thermometry in the assessment of subjects with vibration-induced white finger

The measurement of finger skin temperature (FST) is one of the most commonly used methods for evaluating the response of the digital vessels to cold stimulation. In well-controlled experiments a significant correlation has been observed between FST and digital blood flow over a wide range of water temperatures. On the contrary, FST in air is considered an inadequate index of digital skin circulation since, at a given ambient temperature, FST depends not only on the rate of blood flow through the digit but also on environmental conditions. Despite these limitations, FST recording after a cooling procedure has been used in surveys of vibration-induced white finger (VWF), and a delayed finger rewarming time has been proposed as an indicator of digital vasospasm in workers with VWF. Finger skin thermometry can differentiate between VWF groups and healthy groups, but it is unsuitable for diagnosing Raynaud's phenomenon on an individual basis. The thermometric method has good specificity but its sensitivity is lower than that of plethysmographic techniques. FST after cold provocation may be considered a useful screening test in field studies, while more sensitive methods should be employed to confirm VWF symptoms in individuals objectively, especially for insurance compensation purposes.     

Changes in the forearm tcPO2 following the cold water immersion test

The purpose of this study is to apply changes in forearm transcutaneous PO2 (tcPO2) during the cold water immersion test (5 degrees C, for 10 min) to the diagnosis of vibration syndrome. Forearm tcPO2 in healthy controls increased gradually up to 3 min after the start of the cold water immersion and decreased thereafter. It returned to almost the same level before immersion 5 min after the start. In the workers using vibrating tools manifesting Raynaud's phenomenon, forearm tcPO2 also increased up to 3 min after the start as in healthy controls, but no change was observed thereafter. The difference between the level of forearm tcPO2 at 3 min and that at 10 min after the start of the immersion (Forearm tcPO2 recovery index, newly devised by authors) in workers using vibrating tools was significantly lower than that in healthy controls. Therefore, investigation of changes in forearm tcPO2 following the cold water immersion test is considered to be a useful objective item which can contribute to the diagnosis of vibration syndrome.     

A 4 degrees C-1 min method of cold water immersion test for peripheral circulatory function in fingers]

To assess the validity of a new simplified cold water immersion test (4 degrees C-1 min method) for peripheral circulatory function, comparison was made with the conventional method (10 degrees C-10 min method). These two different methods of cold immersion test were applied to 23 patients with vibration disease and 24 healthy men. Observation was made on finger skin temperature by a thermistor and complaints in the hand by a 5-step self-reported scale method every minute during the test. The patterns of recovery of skin temperature after cold immersion in each group were similar in both methods. Pain in the hand in the 4 degrees C-1 min method was less than that in the 10 degrees C-10 min method. The recovery rate at 5 min in the patients with Raynaud's phenomenon was lower than that in those without Raynaud's phenomenon in the 4 degrees C-1 min method (p < 0.01). However, no significant differences were noted in 10 degrees C-10 min method. The results suggest that the new method is feasible in detecting the response of vasodilation after immersion. In the recovery rate at 5 min after immersion, near values of the sensitivity and specificity were observed between 50% cut-off values in the 4 degrees C-1 min method and 30% value in the 10 degrees C-10 min method. Thus, the 4 degrees C-1 min method is considered to be more useful to evaluate the physiological response after cold immersion than the 10 degrees C-10 min method.