Digital Skin Temperature Research Articles

Neurectomy of the Nerve of Henle Associated with Periarterial Sympathectomy for Management of Intractable Raynaud Phenomenon.

In periarterial sympathectomy for intractable Raynaud phenomenon, the extent of adventitectomy and postoperative outcomes and hand perfusion assessment tools remain debatable. The authors evaluated the outcome of neurectomy of the nerve of Henle combined with ulnar tunnel release and periarterial adventitectomy in the treatment of refractory Raynaud phenomenon using objective measurements and patient-reported outcomes. Nineteen patients with 20 affected hands were prospectively enrolled and underwent the proposed procedures from 2015 to 2021. Relevant data, including Michigan Hand Outcomes Questionnaire and 36-Item Short Form health questionnaire scores, were documented for analysis during a 3-year follow-up. The average ingress value of the three measured fingers (index, long, and ring) on indocyanine green angiography increased after surgery ( P = 0.02). The median number of ulcers decreased ( P < 0.001), and the median digital skin temperature increased ( P < 0.001). Questionnaire scores showed improvement in physical aspects, such as overall hand function ( P ≤ 0.001), activities of daily living ( P = 0.001), work performance ( P = 0.02), pain ( P < 0.001), physical function ( P = 0.053), and general health ( P = 0.048), and mental aspects, such as patient satisfaction ( P < 0.001) and mental health ( P = 0.001). The average indocyanine green ingress value of the three measured fingers significantly correlated with the patient-reported outcomes, including overall hand function ( r = 0.46, P = 0.04), work performance ( r = 0.68, P = 0.001), physical function ( r = 0.51, P = 0.02), and patient satisfaction ( r = 0.35, P= 0.03). The proposed surgical procedures provided satisfactory outcomes, both subjectively and objectively, over a follow-up period of up to 3 years. Indocyanine green angiography may provide rapid and quantitative measurements for perioperative hand perfusion assessment. Therapeutic, IV.

Concordance of temperature measurements on preterm and term infants using oesophageal (core), axilla & skin methods in a neonatal intensive care unit

Aimthe aim of this contemporary paper is to investigate agreement between the axilla, core (oesophageal) and skin method of temperature taking. DesignA comparative descriptive design with a non-probability convenience sample used to describe the difference in recorded temperature by each method in preterm and term infants, gestational age from 24 weeks to term +14 days. MethodAll infants born at 24 weeks and term plus 14 days gestation, admitted to NICU and received parental consent were enrolled in the study. Infants were nursed in various thermal environments.Oesophageal temperature was recorded using the InnerSense sensor/feeding tube (Philips Healthcare, axilla by the BD digital thermometer and skin temperature by the Philips skin temperature probe. ConclusionThe results of this study demonstrate that oesophageal and axilla temperature estimates are very similar, with most differences less than 0.5 °C (CC = 0.63). By contrast, a comparison of oesophageal and skin method temperature estimates shows a much weaker agreement (CC = 0.37).This study confirms that oesophageal temperature taken via the Philips InnerSense can be used safely, as it agrees with the axilla method.Infants nursed in the neonatal intensive care environment, especially when preterm or term with PPHN for example, have special requirements for temperature regulation and minimal handling.

Ski-Everest (8848 m) Expedition: Digit Skin Temperature Responses to Cold Immersion May Reflect Susceptibility to Cold Injury

We tested the hypothesis that individual susceptibility to freezing cold injury might be reflected in an attenuated cold-induced vasodilatation (CIVD) response by comparing the CIVD responses of an elite alpinist with a history of freezing cold injury in the feet (case alpinist) with those of an age- and ability- matched noninjured alpinists control group (controls). According to this hypothesis, the vasomotor responses to a CIVD test of the case alpinist would represent a pathophysiological response when compared with the normal physiological response of a noninjured cohort. The case alpinist and the controls in the cohort group conducted a cold water immersion test comprising sequential immersion of a hand and foot for 5 min in 35°C water, followed by a 30-min immersion in 8°C water and a 10-min recovery period in room air. During this test we monitored the finger and toe skin temperatures. The case alpinist had a significantly attenuated CIVD response and a lower skin temperature in all injured and noninjured digits during immersion (∼2°C lower than in the control group) and an attenuated recovery of finger skin temperatures (∼6°C lower than in the control group). The attenuated CIVD response of the case alpinist may reflect a previously unrecognized enhanced susceptibility to frostbite. In addition to the poor vasomotor response observed in the injured toes, he also exhibited a poor vasomotor response in his noninjured fingers. The results of the present study indicate that a test of vasomotor activity during thermal stress may identify individuals predisposed to cold injury.

Koroška 8000 Himalayan expedition: digit responses to cold stress following ascent to Broadpeak (Pakistan, 8051m).

Cold-induced vasodilatation (CIVD) is a peripheral blood flow response, observed in both the hands and feet. Exercise has been shown to enhance the response, specifically by increasing mean skin temperatures (Tsk), in part due to the increased number of CIVD waves. In contrast, hypobaric hypoxia has been suggested to impair digit skin temperature responses, particularly during subsequent hand rewarming following the cold stimulus. This study examined the combined effect of exercise and hypobaric hypoxia on the CIVD response. We compared the CIVD responses in the digits of both the hands and feet of a team of alpinists (N = 5) before and after a 35-day Himalayan expedition to Broadpeak, Pakistan (8051m). Five elite alpinists participated in hand and foot cold water immersion tests 20 days before and immediately upon return from their expedition. The alpinists summited successfully without supplemental oxygen. Post-expedition, all alpinists demonstrated higher minimum Tsk in their hands (pre: 9.9 ± 1.1, post: 10.1 ± 0.7°C, p = 0.031). Four alpinists had either greater CIVD waves, and, consequently, higher mean Tsk in their hands, or higher recovery temperatures (pre: 26.0 ± 5.5°C post: 31.0 ± 4.1°C, p = 0.052), or faster rewarming rate (pre: 2.6 ± 0.5°Cmin-1 post: 3.1 ± 0.4°Cmin-1,p = 0.052). In the feet, the responses varied: 1/5 had higher wave amplitudes and 1/5 had higher passive recovery temperatures, whereas 3/5 had lower mean toe temperatures during cold exposure. The results of the cold stress test suggest after a 35-day Himalayan expedition, alpinists experienced a slight cold adaptation of the hands, but not the feet.

Skin microvascular reactivity in patients with hypothyroidism.

Hypothyroidism is associated with impaired vascular function; however, little is known about its impact on microcirculation. We aimed to determine skin microvascular reactivity in hypothyroidism focusing on endothelial function and the sympathetic response. We measured skin laser Doppler (LD) flux (LDF) on the volar forearm and the finger pulp using LD flowmetry in hypothyroid patients (N = 13) and healthy controls (N = 15). Skin microvascular reactivity was assessed by a three-minute occlusion of the brachial artery, inducing postocclusive reactive hyperaemia (PRH), and by a four-minute local cooling of the hand. An electrocardiogram (ECG), digital artery blood pressure and skin temperature at the measuring sites were recorded. Baseline LDF, the digital artery blood pressure and the heart rate were comparable between patients and controls. On the other hand, patients exhibited significantly longer PRH duration, significantly higher blood pressure during cooling (unpaired t-test, p <0.05) and lower, albeit not significant, LDF in the ipsilateral finger pulp during cooling compared to controls. Unexpectedly, the results of the present study point to an increased vasodilator capacity of skin microcirculation and an apparent increase in sympathetic reactivity after local cooling in hypothyroid patients. Hypothyroidism induces subtle changes of some haemodynamic parameters in skin microcirculation implying altered endothelial function and altered sympathetic reactivity.

Effects of the Oral Examination on the Equine Temporomandibular Joint

Despite the increasing number of oral examinations performed, reports on temporomandibular joint (TMJ) assessment after the use of full-mouth specula are lacking in the literature. The aim of this study was to investigate whether prolonged application of a full-mouth speculum (60 minutes) would result in alterations in the clinical, thermographic, and synovial fluid (SF) findings. Horses were randomly divided into two groups. In one group, the speculum was kept in place in a closed position (CP group). In the other group, animals remained for 60 minutes with the mouth speculum at full range of aperture (opened position [OP] group). All TMJ joints were evaluated using digital palpation and thermography previous to (baseline values) and 6 hours after the removal of the mouth speculum (M6h). Synovial fluid was collected and analyzed. Six hours after full-mouth speculum use (M6h), pain on digital palpation, skin temperature, and total cell count in the OP group were higher when compared to baseline values. Moreover, pain on digital palpation and total cell count were higher in the OP group when compared to the CP group at M6h. There was no difference in total protein, chondroitin sulfate, hyaluronic acid, and prostaglandin E2 SF concentrations. Based on clinical, thermographic, and SF cell cytological findings, we concluded that TMJs environmental modifications followed the application of a full-opened mouth speculum for 60 minutes. However, these alterations were mild and mainly of inflammatory nature, and there was no indication of an increase in extracellular matrix degradation products in the SF.

Finger and Toe Temperature Responses to Cold After Freezing Cold Injury in Elite Alpinists

To assess whether previous freezing cold injuries (FCI) would affect digit skin temperatures and rewarming rates during a follow-up cold stress test protocol. Nonrandomized control trial. Twenty elite alpinists participated; alpinists with previous FCI requiring digit amputations (injured, INJ: n = 10 total, n = 8 male) were compared with ability-matched, uninjured alpinists (control, CON: n = 10, all male). Digit skin temperature was measured using infrared thermography as an index of peripheral digit perfusion after a cold stress test, which consisted of 30 minutes of immersion in 8°C water. The INJ alpinists' injured toes were warmer (approximately 6%) than their uninjured toes immediately after cold immersion (95% CI, 0.01°C to 1.00°C; P = .05); there were no differences between the rates of rewarming of injured and uninjured toes (INJ, 0.5° ± 0.1°C/min; CON, 0.7° ± 0.3°C/min; P = .16). Although the INJ alpinists had colder injured fingers immediately after the 35°C warm bath compared with their own uninjured fingers (32.2° ± 2.0°C vs 34.5° ± 0.5°C; P = .02), there were no differences observed between the rates of rewarming of injured and uninjured fingers after cold exposure (INJ, 1.1° ± 0.2°C/min; CON, 1.3° ± 0.5°C/min; P = .22). Even after FCI that requires digit amputation, there is no evidence of different tissue rates of rewarming between the injured and uninjured fingers or toes of elite alpinists.

Blinded observer evaluation of distal skin temperature for predicting lateral infraclavicular block success.

Changes in digit skin temperature may be used to predict and determine upper limb nerve block success. We investigated whether a temperature difference between the blocked and the nonblocked hands, simply registered by touching the skin of the 5th and 2nd digit was valid and reliable as a diagnostic test for predicting a successful lateral infraclavicular block. Blinded observers investigated temperature difference between the blocked and the nonblocked hands of 40 patients. Sensitivity, specificity, and predictive values of a positive and a negative test were estimated for evaluating the validity of a temperature difference for predicting a successful lateral infraclavicular block defined by sensory and motor block of all 4 major nerves (musculocutaneous, radial, ulnar, and median nerves). κ statistics of interobserver agreement were used for evaluating the reliability of the test. As a stand-alone test, a temperature difference between the corresponding 2nd and 5th digits of the blocked and the nonblocked hands predicted a successful block with a sensitivity of 92% (95 % confidence interval (CI), 83%-97%) and with a predictive value of a positive test of 95% (CI, 86%-98%). Fleiss κ for multiple observers was 0.74, (CI, 0.61-0.87) for the 5th digit and 0.87 (CI, 0.73-0.998) for the 2nd digit, respectively. We found that a qualitative difference in skin temperature between the blocked and nonblocked hands, measured distally on the 2nd and 5th digits, was a valid and reliable diagnostic test for predicting successful lateral infraclavicular block.

Ultrasound‐guided lateral infraclavicular block evaluated by infrared thermography and distal skin temperature

Brachial plexus blocks cause changes in hand and digit skin temperature. We investigated thermographic patterns after the lateral infraclavicular brachial plexus block. We hypothesised that a successful lateral infraclavicular block could be predicted by increased skin temperature of the 2nd and 5th digits. We performed an ultrasound-guided lateral infraclavicular block in 45 patients undergoing upper limb surgery. The contralateral hand served as control and we obtained infrared thermographic images of both hands before the block and during the following 30 min. We defined areas of interest on the hands and analysed mean skin temperature of each area. Forty patients completed the study. Thirty blocks were successful, six were failures and four were partial failures. Four distinct patterns of skin temperature changes were revealed with highly significant changes in temperature, depending on block success. A simultaneous 1 °C ipsilateral increase in skin temperature of the 2nd and 5th digits predicted a successful block with a positive predictive value of 100%. A 5 °C difference in digit skin temperature compared with the contralateral hand had a positive predictive value of 96%, and a digit skin temperature ≤ 30 °C 30 min after performing the block had a predictive value of 100% for a failed block. Four different thermographic patterns were found. Simultaneous increases in skin temperature of both the 2nd and 5th digits predicted lateral infraclavicular block success with a positive predictive value of 100%. Digit skin temperature ≤ 30 °C 30 min after performing the block indicated block failure.

Open label study of escalating doses of oral treprostinil diethanolamine in patients with systemic sclerosis and digital ischemia: pharmacokinetics and correlation with digital perfusion

IntroductionTreprostinil diethanolamine is an innovative salt form of the prostacyclin analogue, treprostinil sodium, developed as an oral sustained release (SR) osmotic tablet. The availability of a formulation permitting convenient systemic delivery might have applicability to scleroderma vascular complications. We evaluated pharmacokinetics and perfusion in scleroderma patients with digital ischemia following escalating twice-daily doses of treprostinil diethanolamine SR.MethodsScleroderma patients with digital ulcers were enrolled in this dual-center, open-label, phase I pharmacokinetic study. Drug concentrations and perfusion, quantified by laser Doppler imaging, were measured over 12 hours at the 2 mg and 4 mg (or maximally tolerated) doses. Pharmacokinetic parameters were determined from individual plasma concentration versus time profiles using non-compartmental analysis methods. Digital perfusion and skin temperature were modeled as a function of log-transformed drug concentration and other covariates by performing repeated measures analyses using random effects models.ResultsNineteen scleroderma patients (84% female, 53% limited scleroderma) received treprostinil diethanolamine SR with dose titration up to 4 mg twice daily as tolerated. Peak concentrations (mean maximum plasma concentration (Cmax) = 1,176 and 2,107 pg/mL) occurred approximately 3.6 hours after dose administration, and overall exposure (under the plasma concentration-time curve from time 0 to 12 hours post dose (AUC0-12) = 7,187 and 12,992 hr*pg/mL) was linear between the 2 mg and 4 mg doses. Perfusion and digital skin temperature were positively associated with log-transformed plasma concentration at the 4 mg dose (P = 0.015 and P = 0.013, respectively). The most frequent adverse events were similar to those seen with prostacyclin analogues.ConclusionsOral treprostinil diethanolamine was effectively absorbed in patients with scleroderma. Drug administration was temporally associated with improved cutaneous perfusion and temperature. Treprostinil diethanolamine may provide a new therapeutic option for Raynaud's phenomenon and the peripheral vascular disease of scleroderma.Trial RegistrationClinicalTrials.gov NCT00848939.Electronic supplementary materialThe online version of this article (doi:10.1186/ar4216) contains supplementary material, which is available to authorized users.

Efficacy of Rho kinase inhibitor fasudil in secondary Raynaud's phenomenon

The RhoA/Rho kinase pathway plays a pivotal role in cold-induced vasoconstriction, vascular smooth muscle cells function, and vascular homeostasis. This study evaluates the efficacy of fasudil, a RhoA/Rho kinase inhibitor, to reverse cold-induced vasospasm in patients with Raynaud's phenomenon (RP) secondary to systemic sclerosis (SSc; scleroderma). This is a single-center, double-blind, placebo-controlled, randomized, 3-period crossover study of oral fasudil (40 mg or 80 mg) or placebo administered 2 hours before a standardized cold challenge. The fall in skin temperature after the cold challenge and time to recover 50% and 70% of prechallenge digital skin temperature were used as primary outcomes. Digital blood flow assessed by laser Doppler, time to minimum skin temperature, and rate of skin cooling were also measured. A total of 17 patients with SSc and RP completed the study. After the cold challenge, skin temperatures and the average time (minutes) to recover 50% (7.9 minutes for placebo, 7.5 minutes for fasudil 40 mg, and 8.2 minutes for fasudil 80 mg; P = 0.791) and 70% (18.2 minutes for placebo, 15.0 minutes for fasudil 40 mg, and 17.1 minutes for fasudil 80 mg; P = 0.654) of prechallenge skin temperature were not significantly different across the 3 groups. The digital blood flow measurements were higher in fasudil-treated groups than placebo, but differences were not significant (P = 0.693). Fasudil administered at a single oral dose of 40 mg or 80 mg was not associated with significant benefit in terms of the skin temperature recovery time and the digital blood flow after the cold challenge.

Steal in Hemodialysis Patients Depends on Type of Vascular Access

To study incidence and severity of steal phenomena in hemodialysis patients and to investigate possible methods for its detection. A questionnaire was composed based on a literature search. A subgroup of patients having steal as identified by the questionnaire was studied using physical examination, arterial blood pressure, skin temperature, digital oxygenation, grip strength and plethysmography. Contralateral arms served as controls. A cold hand was present in 50% of the patients with a brachiocephalic (BC) arteriovenous fistula (AVF, n = 28) compared to 25% of prosthetic forearm loops (loop, n = 27) and 12% of the radiocephalic (RC, n = 65, p < 0.05) fistulas. Diabetics were at risk for steal (p < 0.001). Intensity of steal was not related to magnitude of access flow. Digital skin temperatures and grip strength were lower in steal hands (p < 0.02). Manual compression of the AVF normalised low digital pressures in steal hands (106 +/- 33 vs 154 +/- 25 mmHg, p < 0.001, contralateral side 155 +/- 21 mmHg). Mild to moderate steal symptoms are common in a hemodialysis patient. Individuals with a BC are at a higher risk for developing complaints associated with reduced hand circulation compared to patients with a RC or loop. Low finger pressures in the presence of steal symptoms are usually reversible.

Stress reactivity and family relationships in the development and treatment of endometriosis

To examine stress physiology and facts of family functioning associated with development and course of endometriosis symptoms. Clinical case data and literature review. Private practice in hospital-affiliated medical office. One woman with endometriosis, her parents, and a nonsymptomatic volunteer. Measures of physiologic and neural reactivity with biofeedback and neurofeedback equipment during family history interview and while sitting quietly. Electroencephalography (EEG), digital skin temperature (DST), electrodermal response (EDR), and electromyography (EMG); facts of family history; contact with family. Endometriosis symptoms were associated with DST, EDR, EMG, and EEG measures indicating prolonged stress reactions for the symptomatic woman and her parents. Facts of family history and relationships for three generations set the stage for stress reactions. Striking differences are evident in the physiology, family history, and contact with family of the nonsymptomatic woman. Differences warrant further study, a larger sample, and additional measures using hormone assay to establish connections between stress reactions in the family, endometriosis symptoms, and response to treatment. Further research will document changes in physiology and in symptoms that accompany interruption of stress reactions with self-regulation training and family systems psychotherapy.

Efficacy and tolerability of a selective α2C‐adrenergic receptor blocker in recovery from cold‐induced vasospasm in scleroderma patients: A single‐center, double‐blind, placebo‐controlled, randomized crossover study

OPC-28326 is a selective alpha-adrenergic antagonist with preferential binding to the alpha(2C)-adrenergic receptor (alpha(2C)-AR) subtype. This study observed the effect of OPC-28326 on skin temperature and digital blood flow following an acute cold challenge in patients with Raynaud's phenomenon secondary to scleroderma. The study was designed as a single-center, double-blind, placebo-controlled, randomized, 3-period crossover study of OPC-28326 (oral doses of 10 mg or 40 mg) or placebo. The primary outcome measures were the time to recover 50% and 70% of the fall (induced by cold challenge) in baseline digital skin temperature. Twelve of 13 enrolled patients completed the study. The mean time to achieve 50% and 70% recovery of the change in prechallenge digital skin temperature was shorter after the OPC-28326 40-mg dose than after placebo (50% recovery at 5.8 minutes versus 10.0 minutes [P = 0.02]; 70% recovery at 13.8 minutes versus 19.5 minutes [P = 0.01]). These recovery times tended to be shorter in the 10 mg OPC-28326 group as well, but the difference versus placebo was not significant (50% recovery at 9.0 minutes versus 10.0 minutes [P = 0.65]; 70% recovery at 15.3 minutes versus 19.5 minutes [P = 0.07]). Total digital blood flow tended to be lower prior to the cold challenge and after administration of 40 mg OPC-28326, as compared with that after placebo, but the difference was not significant. Symptoms that were potentially drug-related were reported more frequently with 40 mg OPC-28326 than with 10 mg OPC-28326 or with placebo, but none were serious or sustained. OPC-28326 at doses of 10 mg and 40 mg was well tolerated during this study. The shorter time to skin temperature recovery after 40 mg OPC-28326 suggests that selective alpha(2C)-AR blockade improves digital skin perfusion during recovery from cooling in patients with Raynaud's phenomenon secondary to scleroderma.

Behavioural treatment of post-traumatic and vibration-induced digital cold sensitivity.

Cold sensitivity is a common problem after all types of hand injuries. The aim of the present study was to assess possible effects of treatment by Pavlovian conditioning, a behavioural treatment method for digital cold sensitivity where whole body cold exposure becomes associated with warm hands. Eighteen hand-injured patients and nine patients with vibration-induced problems in their hands completed the treatment. Questionnaires and questions, assessment of perception of touch/pressure and skin temperatures after cold provocation, was made before and after the completed period of treatment and after 6 and 12 months. The results indicated subjective improvement in the hand-injured group in contrast to a lack of response in the vibration group. An increased digital skin temperature after treatment was noted for the vibration-exposed group only, which however did not persist at 6 and 12 months' follow-up.

Context-dependent effects of steroid chemosignals on human physiology and mood

We examined the physiological and psychological effects of nanomolar amounts of steroids applied directly under the nose (Δ4,16-androstadien-3-one and 1,3,5,(10),16-estratetraen-3-ol). These potential human chemosignals were not consciously discernible in a strong-odor carrier (clove oil and propylene glycol). In a double-blind, within-subject, repeated-measures experiment with 65 subjects, we demonstrated that both steroids produced sustained changes in digit skin temperature and palmar skin conductance (an indicator of sympathetic nervous system tone) while the subjects were completing psychological questionnaires or reading. These effects, however, did not follow the sex-stereotyped pattern predicted by a sex attractant function. Both androstadienone and estratetraenol raised the skin temperature of men's hands and lowered it in women. Likewise, each steroid increased skin conductance, with a significantly greater effect on women than men. Women's responses were observed only in the sessions run by the male tester, an effect that may or may not be solely attributable to tester sex. Men's responses, in contrast, were not affected by this difference in socioexperimental condition. Similarly, women experienced an immediate increase in positive mood only in the presence of the male tester, while men's responses were unaffected by this socioexperimental context. One source of this sex difference may be the fact that the majority of women were in the late follicular phase of their menstrual cycle. Although it is premature to classify these steroids as pheromones, our data suggest that they function as chemosignals that modulate autonomic nervous system tone as well as psychological state.

The Use of Preoperative Noninvasive Vascular Studies for the Evaluation of Radial Artery Conduits for Coronary Artery Bypass Grafting

Background: The increased use of the radial artery for coronary artery bypass conduits has heightened the awareness of potential resultant hand ischemia. The Allen test and subsequent modifications have been used to evaluate the patency of the superficial palmar arch (SPA). The purpose of this study was to determine if changes in blood flow patterns of the SPA assessed by the modified Allen test parallel changes in blood pressures of the first and second digits following radial artery occlusion. Methods: Continuous-wave Doppler ultrasound and photoplethysmography (PPG) were used to evaluate blood flow in the SPA and first and second digits, respectively, before and after manual occlusion of the radial artery in 60 extremities. A second continuouswave Doppler probe was used to ensure complete occlusion of the radial artery. Digit skin temperature was controlled between 36° and 37.5°0. A reduction of &gt;20 mmHg in blood pressure was arbitrarily chosen to reflect a clinically significant change in digit arterial pressure. Results: Six of the 60 extremities (10%) studied showed a decrease in the audible Doppler signal over the SPA following radial artery occlusion. Reduction in digit arterial pressure following radial artery occlusion occurred in 13 of 60 extremities (21.7%). Digit arterial pressure reductions ranged from 20 to 58 mmHg (mean ±SD, 35.2 ±12.8 mmHg), demonstrating a 40% decrease in digital pressure. Changes in SPA flow did not parallel digital pressure changes following occlusion of the radial artery. Conclusion: Continuous-wave Doppler ultrasound of the SPA following radial artery compression alone does not accurately predict digit ischemia. Digit arterial pressure measurement of the first and second digits of upper extremities offers a relatively simple and objective method for evaluation of potential ischemic complications following radial artery harvest. This finding is important because many physicians only use a modified Allen test with radial artery compression to assess potential digit ischemia.

Cocaine effects on digital blood flow and diffusing capacity for carbon monoxide among chronic cocaine users

To determine the acute effects of intravenous (i.v.) cocaine on primarily digital skin blood flow and diffusion capacity for carbon monoxide (CO), and secondarily on subjective and cardiovascular measures. A double-blind, Latin-square, placebo-controlled, dose-response study was conducted in an inpatient general clinical research center and clinical pharmacology unit of a university teaching hospital. Twelve adult males with histories of illicit drug use including i.v. cocaine received 0, 25, and 50 mg of i.v. cocaine given as 1-minute infusions, on 3 consecutive test days. Digital cutaneous blood flow was determined via laser doppler flowmetry and skin temperature. Diffusing capacity for carbon monoxide (DCO) was measured with standard techniques. Subjective responses were measured by oral report of a numerical ranking of strength of drug effect. Heart rate and blood pressure responses were measured by electronic sphygmomanometer. A maximal decrease in skin blood flow occurred at 2 to 3 minutes after infusion, and was not distinguished among drug conditions. Blood flow returned to baseline more rapidly after placebo than after cocaine: 7 minutes (placebo), 35 minutes (25 mg cocaine), 50 minutes (50 mg cocaine). Skin temperature decreased by 1.25 degrees C after placebo and by 2.75 and 3.25 degrees C after 25 and 50 mg of cocaine, respectively. DCO changed by -1.02 (mean) +/- 0.25 (standard deviation), 0.16 +/- 1.22, and 0.21 +/- 1.63 ml/min/mm Hg following placebo, 25, and 50 mg of cocaine, respectively. Typical subjective, chronotropic, and pressor responses to cocaine were demonstrated, and these occurred in close temporal relationship to digital blood flow and skin temperature responses. The digital cutaneous circulation is highly sensitive to vasoconstrictor effects of cocaine. Pulmonary blood volume tends to be preserved after i.v. cocaine. Subjective effects and cardiovascular responses occur in concert with peripheral blood flow changes. The peripheral vasoconstrictor effects have implications for cocaine users with concurrent vasospastic or vasculopathic disorders.

Digital skin temperature and biofeedback.

The present study simultaneously compared the skin temperature of the index and the little fingers during hand warming using biofeedback. There was a 5-min. baseline recording followed by a 10-min. session during which subjects attempted to increase skin temperature using the index finger with biofeedback in the form of lights and sound. Analysis showed no significant differences between the temperatures of the index and of the little fingers, but there was a significant increase in temperature during the session for both sites.

Correlation of Photoplethysmography, Doppler Velocimetry, Digital Blood Pressure and Skin Temperature in the Hand Under Conditions of Warming

Correlation of Photoplethysmography, Doppler Velocimetry, Digital Blood Pressure and Skin Temperature in the Hand Under Conditions of Warming