Higher Cortical Facilitation and Serum BDNF Are Associated with Increased Sensitivity to Heat Pain and Reduced Endogenous Pain Inhibition in Healthy Males.

Background: Although the brain-derived neurotrophic factor (BDNF) has been intensively investigated in animal models of chronic pain, its role in human pain processing is less understood. Objective: To study the neurophysiology of BDNF modulation on acute experimental pain, we performed a cross-sectional study. Methods: We recruited 20 healthy male volunteers (19-40 years old) and assessed their serum BDNF levels, quantitative sensory testing, and cortical excitability parameters using transcranial magnetic stimulation. Results: Linear regression models demonstrated that the BDNF (ß = -5.245, P = 0.034) and intracortical facilitation (ß = -3.311, P = 0.034) were inversely correlated with heat pain threshold (adjusted R2 = 44.26). The BDNF (ß = -3.719, P ≤ 0.001) was also inversely correlated with conditioned pain modulation (adjusted R2 = 56.8). Conclusions: Our findings indicate that higher serum BDNF and intracortical facilitation of the primary motor cortex are associated with increased sensitivity to heat pain and high serum BDNF with reduced pain inhibition during noxious heterotopic stimulation.

Postoperative intensive care allocation and mortality in high-risk surgical patients: evidence from a low- and middle-income country cohort.

BACKGROUND: The escalation of surgeries for high-risk patients in Low- and Middle-Income Countries (LMICs) lacks evidence on the positive impact of Intensive Care Unit (ICU) admission and lacks universal criteria for allocation. This study explores the link between postoperative ICU allocation and mortality in high-risk patients within a LMIC. Additionally, it assesses the Ex-Care risk model's utility in guiding postoperative allocation decisions. METHODS: A secondary analysis was conducted in a cohort of high-risk surgical patients from a 800-bed university-affiliated teaching hospital in Southern Brazil (July 2017 to January 2020). Inclusion criteria encompassed 1431 inpatients with Ex-Care Model-assessed all-cause postoperative 30-day mortality risk exceeding 5%. The study compared 30-day mortality outcomes between those allocated to the ICU and the Postanesthetic Care Unit (PACU). Outcomes were also assessed based on Ex-Care risk model classes. RESULTS: Among 1431 high-risk patients, 250 (17.47%) were directed to the ICU, resulting in 28% in-hospital 30-day mortality, compared to 8.9% in the PACU. However, ICU allocation showed no independent effect on mortality (RR = 0.91; 95% CI 0.68‒1.20). Patients in the highest Ex-Care risk class (Class IV) exhibited a substantial association with mortality (RR = 2.11; 95% CI 1.54-2.90) and were more frequently admitted to the ICU (23.3% vs. 13.1%). CONCLUSION: Patients in the highest Ex-Care risk class and those with complications faced elevated mortality risk, irrespective of allocation. Addressing the unmet need for adaptable postoperative care for high-risk patients outside the ICU is crucial in LMICs. Further research is essential to refine criteria and elucidate the utility of risk assessment tools like the Ex-Care model in assisting allocation decisions.

Development of a recovery-room discharge checklist (SAMPE checklist) for safe handover and its comparison with Aldrete and White scoring systems.

BACKGROUND: The postoperative care transition from the postanesthetic recovery room (PACU) to the common ward or even home discharge represents a critical step of the surgical patients' handover. Although some systems have been proposed to measure the ability to discharge after an anesthetic-surgical procedure effectively, there is no consensus defining which variables should necessarily be evaluated by these instruments. The instruments routinely used do not evaluate important domains for discharge and are laborious to fill, which compromises the professionals' adhesion. The objectives are to describe the creation of a new recovery room discharge tool (SAMPE checklist) and determine the degree of agreement of the new tool with two classical scales. METHODS: In a cross-sectional observational study, 997 patients were selected from the general population undergoing a wide range of surgical procedures in a quaternary care hospital. At 90 minutes after leaving the operating room (OR), patients were evaluated and information was collected to fill out the new SAMPE checklist and two other scores (Aldrete and White) to examine the degree of agreement between them. RESULTS: SAMPE checklist has presented a satisfactory agreement with the White score and lower agreement with Aldrete modified score. CONCLUSION: This new instrument, as demonstrated in this study with nearly 1000 patients from different contexts, is easy to apply, has high adhesion potential, and can be considered a new option to formalize the discharge from the recovery room.

Validation of the Brazilian version of the child pain catastrophizing scale and its relationship with a marker of central sensitization.

OBJECTIVES: The Pain Catastrophizing Scale-Child version (PCS-C) allows to identify children who are prone to catastrophic thinking. We aimed to adapt the Brazilian version of PCS-C (BPCS-C) to examine scale psychometric properties and factorial structure in children with and without chronic pain. Also, we assessed its correlation with salivary levels of Brain-Derived Neurotrophic factor (BDNF). METHODS: The Brazilian version of PCS-C was modified to adjust it for 7-12 years old children. To assess psychometric properties, 100 children (44 with chronic pain from a tertiary hospital and 56 healthy children from a public school) answered the BPCS-C, the visual analogue pain scale, and questions about pain interference in daily activities. We also collected a salivary sample to measure BDNF. RESULTS: We observed good internal consistency (Cronbach's value = 0.81). Parallel analysis retained 2 factors. Confirmatory factor analysis of our 2-factor model revealed consistent goodness-of-fit (IFI = 0.946) when compared to other models. There was no correlation between visual analogue pain scale and the total BPCS-C score; however, there was an association between pain catastrophizing and difficulty in doing physical activities in school (p = 0.01). BPCS-C total scores were not different between groups. We found a marginal association with BPCS-C (r = 0.27, p = 0.01) and salivary BDNF levels. DISCUSSION: BPCS-C is a valid instrument with consistent psychometric properties. The revised 2-dimension proposed can be used for this population. Children catastrophism is well correlated with physical limitation, but the absence of BPCS-C score differences between groups highlights the necessity of a better understanding about catastrophic thinking in children.

The impact of the incorporation of a feasible postoperative mortality model at the Post-Anaesthestic Care Unit (PACU) on postoperative clinical deterioration: A pragmatic trial with 5,353 patients.

BACKGROUND: Practical use of risk predictive tools and the assessment of their impact on outcome reduction is still a challenge. This pragmatic study of quality improvement (QI) describes the preoperative adoption of a customised postoperative death probability model (SAMPE model) and the evaluation of the impact of a Postoperative Anaesthetic Care Unit (PACU) pathway on the clinical deterioration of high-risk surgical patients. METHODS: A prospective cohort of 2,533 surgical patients compared with 2,820 historical controls after the adoption of a quality improvement (QI) intervention. We carried out quick postoperative high-risk pathways at PACU when the probability of postoperative death exceeded 5%. As outcome measures, we used the number of rapid response team (RRT) calls within 7 and 30 postoperative days, in-hospital mortality, and non-planned Intensive Care Unit (ICU) admission. RESULTS: Not only did the QI succeed in the implementation of a customised risk stratification model, but it also diminished the postoperative deterioration evaluated by RRT calls on very high-risk patients within 30 postoperative days (from 23% before to 14% after the intervention, p = 0.05). We achieved no survival benefits or reduction of non-planned ICU. The small group of high-risk patients (13% of the total) accounted for the highest proportion of RRT calls and postoperative death. CONCLUSION: Employing a risk predictive tool to guide immediate postoperative care may influence postoperative deterioration. It encouraged the design of pragmatic trials focused on feasible, low-technology, and long-term interventions that can be adapted to diverse health systems, especially those that demand more accurate decision making and ask for full engagement in the control of postoperative morbi-mortality.

The Brief Measure of Emotional Preoperative Stress (B-MEPS) as a new predictive tool for postoperative pain: A prospective observational cohort study.

BACKGROUND: Preoperative patients' vulnerabilities such as physical, social, and psychological are implicated in postoperative pain variability. Nevertheless, it is a challenge to analyze a patient's psychological profile in the preoperative period in a practical and consistent way. Thus, we sought to identify if high preoperative emotional stress, evaluated by the Brief Measure of Emotional Preoperative Stress (B-MEPS) scale is associated with higher postoperative pain levels and poor rehabilitation in patients submitted to intermediate or major surgery. Moreover, the possible neurobiological or neurophysiological mechanisms implicated in high preoperative emotional stress, evaluated through preoperative quantitative sensory pain tests and serum biomarkers BDNF and S100B were investigated. METHODS: We conducted a prospective, observational, cohort study of ASA 2 and 3 adult patients undergoing major urologic, gynecologic, proctologic and orthopedic surgeries from March 2017 to March 2018. B-MEPS and Central Sensitivity Inventory were evaluated preoperatively, followed by a sequence of experimental pain tests and serum biomarkers collection. Postoperative evaluation carried out within the first 48 hours after surgery comprehended pain at rest and movement-evoked pain, and the consumption of morphine. Quality-of-Recovery was also evaluated in the 3rd postoperative day. RESULTS: 23 (15%) out of 150 patients included in the study presented high emotional preoperative stress. Variables significantly related to preoperative stress were: previous psychiatric diagnosis and Central Sensitization Inventory result. Mean movement-evoked pain in the first 12 to 48 hours was 95-105% higher than pain at rest. A mixed model for repeated measures showed a sustainable effect of B-MEPS as a movement-evoked pain predictor. Previous pain, cancer surgery, and preoperative pressure pain tolerance were also independent predictors of postoperative pain. Moderate to severe postoperative movement-evoked pain was predictive of poor rehabilitation in 48 hours after surgery. CONCLUSION: We confirmed that a brief screening method of preoperative emotional states could detect individuals prone to experience severe postoperative pain. Specific interventions considering the stress level may be planned in the future to improve perioperative outcomes.

BDNF and serum S100B levels according the spectrum of structural pathology in chronic pain patients.

Central sensitivity syndrome (CSS) consists of adaptive pathophysiological changes associated with neuroplasticity in some chronic pain disorders. It could be grouped in two main conceptual conditions: one includes those chronic pain patients without overt structural pathology such as fibromyalgia, and the other subgroup includes conditions with recognizable structural abnormalities, both somatic (osteoarthritis) and visceral (endometriosis). In order to understand the role of neuromodulators in CCS we aim to determine whether brain-derived neurotrophic factor (BDNF) and S100B are associated to specific chronic pain disorders. Serum BDNF and S100B were measured in chronic pain women with different diagnosis: 88 with osteoarthritis, 36 with endometriosis, 117 with fibromyalgia, 33 with chronic tension type headache and in 41 healthy controls. ANCOVA analysis followed by heteroscedasticity-consistent covariance matrix was performed to evaluate BDNF and S100B levels, adjusted for depression severity, pain levels and use of analgesics according different pathologies. Serum BDNF concentrations were higher and not different in patients with fibromyalgia and headache, the CSS group without structural pathology. In contrast, the concentrations of S100B were higher in patients with osteoarthritis and endometriosis, in comparison to controls, fibromyalgia and tensional headache patients. This study supports the hypothesis that BDNF and S100B neuromodulators present different serum levels according to the background disease associated to the chronic pain. These have the potential to be studied as markers of active disease or treatment evolution.

Derivation and validation of a preoperative risk model for postoperative mortality (SAMPE model): An approach to care stratification.

Ascertaining which patients are at highest risk of poor postoperative outcomes could improve care and enhance safety. This study aimed to construct and validate a propensity index for 30-day postoperative mortality. A retrospective cohort study was conducted at Hospital de Clínicas de Porto Alegre, Brazil, over a period of 3 years. A dataset of 13524 patients was used to develop the model and another dataset of 7254 was used to validate it. The primary outcome was 30-day in-hospital mortality. Overall mortality in the development dataset was 2.31% [n = 311; 95% confidence interval: 2.06-2.56%]. Four variables were significantly associated with outcome: age, ASA class, nature of surgery (urgent/emergency vs elective), and surgical severity (major/intermediate/minor). The index with this set of variables to predict mortality in the validation sample (n = 7253) gave an AUROC = 0.9137, 85.2% sensitivity, and 81.7% specificity. This sensitivity cut-off yielded four classes of death probability: class I, <2%; class II, 2-5%; class III, 5-10%; class IV, >10%. Model application showed that, amongst patients in risk class IV, the odds of death were approximately fivefold higher (odds ratio 5.43, 95% confidence interval: 2.82-10.46) in those admitted to intensive care after a period on the regular ward than in those sent to the intensive care unit directly after surgery. The SAMPE (Anaesthesia and Perioperative Medicine Service) model accurately predicted 30-day postoperative mortality. This model allows identification of high-risk patients and could be used as a practical tool for care stratification and rational postoperative allocation of critical care resources.

Validation of the Brazilian version of the child pain catastrophizing scale and its relationship with a marker of central sensitization

Abstract Objectives The Pain Catastrophizing Scale-Child version (PCS-C) allows to identify children who are prone to catastrophic thinking. We aimed to adapt the Brazilian version of PCS-C (BPCS-C) to examine scale psychometric properties and factorial structure in children with and without chronic pain. Also, we assessed its correlation with salivary levels of Brain-Derived Neurotrophic factor (BDNF). Methods The Brazilian version of PCS-C was modified to adjust it for 7-12 years old children. To assess psychometric properties, 100 children (44 with chronic pain from a tertiary hospital and 56 healthy children from a public school) answered the BPCS-C, the visual analogue pain scale, and questions about pain interference in daily activities. We also collected a salivary sample to measure BDNF. Results We observed good internal consistency (Cronbach's value = 0.81). Parallel analysis retained 2 factors. Confirmatory factor analysis of our 2-factor model revealed consistent goodness-of-fit (IFI = 0.946) when compared to other models. There was no correlation between visual analogue pain scale and the total BPCS-C score; however, there was an association between pain catastrophizing and difficulty in doing physical activities in school (p= 0.01). BPCS-C total scores were not different between groups. We found a marginal association with BPCS-C (r= 0.27, p= 0.01) and salivary BDNF levels. Discussion BPCS-C is a valid instrument with consistent psychometric properties. The revised 2-dimension proposed can be used for this population. Children catastrophism is well correlated with physical limitation, but the absence of BPCS-C score differences between groups highlights the necessity of a better understanding about catastrophic thinking in children.

Preoperative transcranial direct current stimulation: Exploration of a novel strategy to enhance neuroplasticity before surgery to control postoperative pain. A randomized sham-controlled study.

BACKGROUND: An imbalance in the excitatory/inhibitory systems in the pain networks may explain the persistent chronic pain after hallux valgus surgery. Thus, to contra-regulate this dysfunction, the use of transcranial direct current stimulation (tDCS) becomes attractive. OBJECTIVE: We tested the hypothesis that two preoperative active(a)-tDCS sessions compared with sham(s)-tDCS could improve the postoperative pain [as indexed by Visual Analogue Scale (VAS) at rest and during walking (primary outcomes)]. To assess their effect on the change in the Numerical Pain Scale (NPS0-10) during Conditioned Pain Modulation (CPM-task), disability related to pain (DRP) and analgesic consumption (secondary outcomes). Also, we assessed if the brain derived neurotrophic factor (BDNF) in the cerebral spinal fluid (CSF) after tDCS could predict the intervention's effect on the DRP. METHODS: It is a prospective, double blind, sham-controlled, randomized single center, 40 women (18-70 years-old) who had undergone hallux valgus surgery were randomized to receive two sessions (20 minutes each) of anodal a-tDCS or s-tDCS on the primary motor cortex at night and in the morning before the surgery. To assess the DRP was used the Brazilian Profile of Chronic Pain: Screen (B-PCP:S). RESULTS: A-tDCS group showed lower scores on VAS at rest and during walking (P<0.001). At rest, the difference between groups was 2.13cm (95%CI = 1.59 to 2.68) while during walking was 1.67cm (95%CI = 1.05 to 2.28). A-tDCS, when compared to s-tDCS reduced analgesic doses in 73.25% (P<0.001), produced a greater reduction in B-PCP:S (mean difference of 9.41 points, 95%CI = 0.63 to 18.21) and higher function of descending pain modulatory system (DPMS) during CPM-task. CONCLUSION: A-tDCS improves postoperative pain, the DRP and the function of DPMS. Also, the CSF BDNF after a-tDCS predicted the improvement in the DRP. In overall, these findings suggest that a-tDCS effects may be mediated by top-down regulatory mechanisms associated with the inhibitory cortical control. TRIAL REGISTRATION: ClinicalTrials.gov NCT02360462.

Combined neuromodulatory interventions in acute experimental pain: assessment of melatonin and non-invasive brain stimulation.

Transcranial direct current stimulation (tDCS) and melatonin can effectively treat pain. Given their potentially complementary mechanisms of action, their combination could have a synergistic effect. Thus, we tested the hypothesis that compared to the control condition and melatonin alone, tDCS combined with melatonin would have a greater effect on pain modulatory effect, as assessed by quantitative sensory testing (QST) and by the pain level during the Conditioned Pain Modulation (CPM)-task. Furthermore, the combined treatment would have a greater cortical excitability effect as indicated by the transcranial magnetic stimulation (TMS) and on the serum BDNF level. Healthy males (n = 20), (aged 18-40 years), in a blinded, placebo-controlled, crossover, clinical trial, were randomized into three groups: sublingual melatonin (0.25 mg/kg) + a-tDCS, melatonin (0.25 mg/kg) + sham-(s)-tDCS, or sublingual placebo+sham-(s)-tDCS. Anodal stimulation (2 mA, 20 min) was applied over the primary motor cortex. There was a significant difference in the heat pain threshold (°C) for melatonin+a-tDCS vs. placebo+s-tDCS (mean difference: 4.86, 95% confidence interval [CI]: 0.9 to 8.63) and melatonin+s-tDCS vs. placebo+s-tDCS (mean: 5.16, 95% CI: 0.84 to 8.36). There was no difference between melatonin+s-tDCS and melatonin+a-tDCS (mean difference: 0.29, 95% CI: -3.72 to 4.23). The mean change from the baseline on amplitude of motor evocate potential (MEP) was significantly higher in the melatonin+a-tDCS (-19.96% ± 5.2) compared with melatonin+s-tDCS group (-1.36% ± 5.35) and with placebo+s-tDCS group (3.61% ± 10.48), respectively (p < 0.05 for both comparisons). While melatonin alone or combined with a-tDCS did not significantly affect CPM task result, and serum BDNF level. The melatonin effectively reduced pain; however, its association with a-tDCS did not present an additional modulatory effect on acute induced pain.

Anesthesia preoperative evaluation clinic (APEC) restructuring plan for improving the quality of surgical patient flow

Introduction: Anesthesia preoperative evaluation clinics (APECs) are useful for high-risk surgical patient care, as they improve perioperative outcomes and optimize patient care flow. At Hospital de Clínicas de Porto Alegre, APEC assesses 20% of all patients undergoing surgery, showing the importance of implementing strategies to improve outpatient clinic efficiency by prioritizing high-risk patients. Methods: Using a specific quality management tool for process improvement (PDCA, which stands for Plan/Do/Check/Act), new protocols were developed for patient referral and preoperative evaluation. Clinical staff was trained in the new routines, and an electronic screening system for patient referral was adopted. Data on patient profiles, referring surgical specialties, type of surgery, and waiting times for appointment and surgical procedure were compared before and after the intervention. Results: APEC performed 1,286 appointments between 2013 and 2016, including 733 pre-intervention and 553 post-intervention. There was a significant decrease in the appointments for patients undergoing minor surgery and an increase in the appointments for those undergoing major surgery. The waiting time between referral to APEC and first APEC appointment reduced from 46 to 16 days. In addition, there was an increase in vascular, orthopedic, and urology referrals, as well as a reduction in ophthalmology and general surgery referrals. Conclusions: The PDCA method assisted with conceiving, executing, and monitoring the implemented strategies for changing the profile of patients evaluated at APEC. The major challenge is to measure the long-term impact of this intervention and expand care through specific strategies for surgical specialties and procedures.(AU)

A Phase II, Randomized, Double-Blind, Placebo Controlled, Dose-Response Trial of the Melatonin Effect on the Pain Threshold of Healthy Subjects.

BACKGROUND: Previous studies have suggested that melatonin may produce antinociception through peripheral and central mechanisms. Based on the preliminary encouraging results of studies of the effects of melatonin on pain modulation, the important question has been raised of whether there is a dose relationship in humans of melatonin on pain modulation. OBJECTIVE: The objective was to evaluate the analgesic dose response of the effects of melatonin on pressure and heat pain threshold and tolerance and the sedative effects. METHODS: Sixty-one healthy subjects aged 19 to 47 y were randomized into one of four groups: placebo, 0.05 mg/kg sublingual melatonin, 0.15 mg/kg sublingual melatonin or 0.25 mg/kg sublingual melatonin. We determine the pressure pain threshold (PPT) and the pressure pain tolerance (PPTo). Quantitative sensory testing (QST) was used to measure the heat pain threshold (HPT) and the heat pain tolerance (HPTo). Sedation was assessed with a visual analogue scale and bispectral analysis. RESULTS: Serum plasma melatonin levels were directly proportional to the melatonin doses given to each subject. We observed a significant effect associated with dose group. Post hoc analysis indicated significant differences between the placebo vs. the intermediate (0.15 mg/kg) and the highest (0.25 mg/kg) melatonin doses for all pain threshold and sedation level tests. A linear regression model indicated a significant association between the serum melatonin concentrations and changes in pain threshold and pain tolerance (R(2)  = 0.492 for HPT, R(2)  = 0.538 for PPT, R(2)  = 0.558 for HPTo and R(2)  = 0.584 for PPTo). CONCLUSIONS: The present data indicate that sublingual melatonin exerts well-defined dose-dependent antinociceptive activity. There is a correlation between the plasma melatonin drug concentration and acute changes in the pain threshold. These results provide additional support for the investigation of melatonin as an analgesic agent. Brazilian Clinical Trials Registry (ReBec): (U1111-1123-5109). IRB: Research Ethics Committee at the Hospital de Clínicas de Porto Alegre.

BDNF as an effect modifier for gender effects on pain thresholds in healthy subjects.

BDNF is an important marker of neuronal plasticity. It has also been associated with pain processing. Increased BDNF levels are observed in chronic pain syndromes. In order to understand the role of BDNF associated with other factors such as gender on experimental pain we aimed to determine whether experimental heat or pressure pain threshold is correlated with brain derived neurotrophic factor (BDNF) level, gender and age. Heat pain threshold and pressure pain threshold were measured in 49 healthy volunteers (27 females). The multivariate linear regression models (on heat and pressure pain thresholds) revealed a significant effect of gender (p=0.001 for both models), serum BDNF (p<0.004 for both models) and interaction between BDNF and gender (<0.001 for both models). In fact, when adjusting for BDNF levels and age, heat and pressure pain thresholds were significantly reduced in women as compared to men (p<0.001 for both models). These effects were not observed when gender was analyzed alone. These finding suggests that experimental heat and pressure pain threshold is gender-related and BDNF dependent. In fact BDNF has a facilitatory effect on pain threshold in females but has an opposite effect in males; supporting the notion that BDNF is an effect modifier of the gender effects on pain threshold in healthy subjects.

Validation of a Brazilian quantitative sensory testing (QST) device for the diagnosis of small fiber neuropathies.

Quantitative sensory testing (QST) is defined as the determination of thresholds for sensory perception under controlled stimulus. Our aim was to validate a new QST device for Brazilian sample. In 20 healthy adults, thermoalgesic thresholds were assessed using a QST prototype (Heat Pain Stimulator-1.1.10; Brazil). A 30 × 30 mm(2) thermode with a 1°C/s stimulus change rate were applied. Thresholds of three consecutive stimuli were averaged in two different sessions separated by at least two weeks. Additionally long thermal heat pain stimulus was performed. To evaluate the consistency of our method we also analyzed 11 patients with small fiber neuropathy. Results showed good reproducibility of thermal perception thresholds in normal individuals and plausible abnormal thresholds in patients. We conclude that our QST device is reliable when analyzing the nociceptive pathway in controls and patients.

Validation of a Brazilian quantitative sensory testing (QST) device for the diagnosis of small fiber neuropathies / Validação de um aparelho brasileiro de teste de quantificação sensitiva brasileiro para o diagnóstico de neuropatia de fibras finas

Quantitative sensory testing (QST) is defined as the determination of thresholds for sensory perception under controlled stimulus. Our aim was to validate a new QST device for Brazilian sample. In 20 healthy adults, thermoalgesic thresholds were assessed using a QST prototype (Heat Pain Stimulator-1.1.10; Brazil). A 30 × 30 mm² thermode with a 1°C/s stimulus change rate were applied. Thresholds of three consecutive stimuli were averaged in two different sessions separated by at least two weeks. Additionally long thermal heat pain stimulus was performed. To evaluate the consistency of our method we also analyzed 11 patients with small fiber neuropathy. Results showed good reproducibility of thermal perception thresholds in normal individuals and plausible abnormal thresholds in patients. We conclude that our QST device is reliable when analyzing the nociceptive pathway in controls and patients.

Teste de quantificação sensitiva (TQS) significa determinação de limiares de percepção sensitiva frente a um estímulo de intensidade controlada. Nosso objetivo foi validar um novo equipamento de TQS adaptado à população brasileira. Em 20 adultos saudáveis, limiares termoalgésicos foram avaliados, utilizando um aparelho protótipo do TQS (Heat Pain Stimulator-1.1.10; Brazil). Foi utilizado um termodo de 30 × 30 mm², com estímulo térmico de 1°C/s. A média dos limiares de três estímulos consecutivos foi obtida em duas sessões diferentes, separadas por pelo menos 2 semanas. Adicionalmente, foram aplicados estímulos térmicos dolorosos de longa duração. Para avaliar a consistência do nosso método, foram também analisados 11 pacientes com neuropatia de fibras finas. Os resultados mostraram boa reprodutibilidade dos limiares de percepção nos indivíduos saudáveis, assim como limiares anormais nos pacientes. Em conclusão, nosso aparelho de TQS apresentou boa confiabilidade ao analisar a via nociceptiva de controles e pacientes.