[Virtual reality in the outpatient: reducing anxiety and fear in venous puncture]. / Realidad virtual en el paciente ambulatorio: reduciendo la ansiedad y el miedo en la punción de vías venosas.

Up to 80% of children admitted to a hospital experience pain, mainly associated with venipuncture. OBJECTIVE: To analyze whether the use of virtual reality (VR) headsets during venipuncture can modify the perception of pain, anxiety, and fear in pediatrics. PATIENTS AND METHOD: Open label, randomized clinical trial. The presence of intellectual, visual, or hearing impairment were considered exclusion criteria. Two anxiety and fear scales were administered before and after the procedure, and the Wong-Baker face pain scale at the end. The following were recorded: number of venipuncture attempts, duration of the procedure, and side effects. RESULTS: 78 patients were included, 38 males and a mean age of 9.63 years. In the intervention group, the mean pain value was 2.87, with a mean difference (MD) of -0.85 compared with the control one (95% confidence interval (CI) -2.02 to 0.33). There was a significant reduction in the level of anxiety and fear, with MDs of -2.59 (95%CI: -3.92 to -1.26) and -0.85 points (95%CI: -1.45 to -0.24), respectively. CONCLUSIONS: the use of VR headsets in venipuncture in hospital daytime care decreases the level of anxiety and fear in children and seems to reduce pain, without adverse effects. The venipuncture procedure has the same success rate and does not increase its duration.

Impact of virtual reality on peri-interventional pain, anxiety and distress in a pediatric oncology outpatient clinic: a randomized controlled trial.

PURPOSE: Pain and anxiety-inducing interventions have a major impact on pediatric patients. Pain reduction by virtual reality (VR) during port and vein punctures is well studied. This study investigates peri-interventional reduction of pain, anxiety and distress using VR compared to the standard of care (SOC) in a pediatric oncology outpatient clinic. METHODS: In a randomized, controlled cross-over design, patients aged 6-18 years experience potentially painful interventions accompanied by VR. Observational instruments include NRS, FPS-r, BAADS, mYPAS-SF, PedsQL and SSKJ3-8R. All patients undergo two observations: SOC (A) and VR (B) in a randomized order. In addition, parents and staff are interviewed. Specific conditions for VR in an outpatient clinic setting derived from interprofessional focus group discussion are being explored. RESULTS: Between July 2021 and December 2022 57 eligible patients were included and randomized to the orders A/B (n = 28) and B/A (n = 29). Thirty-eight patients completed both observations. Characteristics in both groups did not differ significantly. More than half of the patients had no previous experience with VR, 5% decided to discontinue VR prematurely. Peri-interventional pain, anxiety and distress were significantly reduced by VR compared with SOC. 71% of patients and 76% of parents perceived punctures with VR to be more relaxed than previous ones. 95% of patients perceived fun with VR goggles. Detailed questionnaires on individual stress and anxiety were returned from 26 of 38 patients. Focus group discussion with staff yielded evidence for successful implementation of VR in an outpatient clinic. CONCLUSIONS: The present study shows that VR can be used for peri-interventional reduction of pain, anxiety, and distress in the special environment of a pediatric outpatient clinic. Specific conditions must be met for successful implementation. Further studies are needed to identify particularly susceptible patients and to illuminate alternatives for distraction that are feasible to implement with limited resources. TRIAL REGISTRATION NUMBER: (ClinicalTrials.gov ID): NCT06235723; 01/02/2024; retrospectively registered. This study adheres to the standard checklist of CONSORT guidelines.

EMLA cream in burns: A systematic review of safety, analgesic efficacy, and effects on burn pathophysiology.

AIM: Management of procedural pain in burn care is challenging. Lidocaine-prilocaine cream 5%, eutectic mixture of local anesthetics (EMLA®), is a widely used, effective local anesthetic cream approved for normal intact skin, genital mucosa for superficial surgical procedures, and debridement of chronic leg ulcers. This comprehensive review aimed to determine the safety, analgesic efficacy, and effects of EMLA on burn pathophysiology to provide evidence-based clinical recommendations for introducing the topical anesthetic into burn care. METHODS: The PRISMA guidelines were followed for conducting a systematic PubMed search to include all relevant preclinical and clinical studies, according to pre-specified eligibility criteria. RESULTS: Fifteen studies were included in a qualitative synthesis, among which nine were human and six were animal studies. To date, safety and pharmacokinetic data on EMLA application in burns have been limited. Nevertheless, human studies indicated that EMLA is safe and provides adequate procedural-pain relief in adults when applied to smaller burns. Caution should be exercised when using EMLA in younger children, as systemic toxicity, pertaining to prilocaine-induced methemoglobinemia, has been reported owing to overdosing (high doses applied over large burn areas). Furthermore, animal studies demonstrate the potential beneficial effects of EMLA on burn pathophysiology such as anti-inflammatory, decreased capillary permeability to plasma proteins and edema formation, and improved tissue perfusion, which are factors that may impact burn wound progression. CONCLUSION: Current data on EMLA use in the management of procedural pain in small burns are sparse but suggest that EMLA is safe and effective in adults. Further clinical pharmacokinetic studies are warranted, especially for application on larger burn areas.

Optimizing pediatric periprocedural pain management part II-Adjunct therapies to support the use of infiltrative anesthetics.

Pediatric procedure-related pain management is often incompletely understood, inadequately addressed, and critical in influencing a child's lifelong relationship with the larger healthcare community. We present a comprehensive review of infiltrative anesthetics, including a comparison of their mechanisms of action and relative safety and efficacy data to help guide clinical selection. We also describe the multimodal utilization of adjunct therapies-in series and in parallel-to support the optimization of pediatric periprocedural pain management, enhance the patient experience, and provide alternatives to sedation medication and general anesthesia.

Strategies to minimize procedure-related pain and anxiety: lessons from pediatric dermatology.

PURPOSE OF REVIEW: Recent studies have suggested that prolonged or repeated episodes of general anesthesia early in childhood may adversely affect neurodevelopment. This, combined with rising healthcare costs and decreasing access, has sparked interest in performing pediatric procedures in the office setting when possible. It is essential to address the physical and psychological discomfort that often accompany this experience, particularly in children. RECENT FINDINGS: Healthcare providers performing procedures on children can draw from a spectrum of established techniques, new technology, and novel use of medications to decrease peri-procedural pain and anxiety. These techniques include distraction, optimization of local anesthesia, and mild to moderate sedation. SUMMARY: We recommend using a combination of techniques to minimize pain and anxiety to improve safety, decrease healthcare costs, improve patient experience, and prevent childhood trauma and persistent negative perception of the healthcare system.

Cumulative sucrose exposure for repeated procedural pain in preterm neonates and neurodevelopment at 18 months of corrected age: a prospective observational longitudinal study.

INTRODUCTION: Oral sucrose is repeatedly administered to neonates in the neonatal intensive care unit (NICU) to treat pain from commonly performed procedures; however, there is limited evidence on its long-term cumulative effect on neurodevelopment. We examined the association between total sucrose volumes administered to preterm neonates for pain mitigation in the NICU and their neurodevelopment at 18 months of corrected age (CA). METHODS: A prospective longitudinal single-arm observational study that enrolled hospitalised preterm neonates <32 weeks of gestational age at birth and <10 days of life was conducted in four level III NICUs in Canada. Neonates received 0.1 mL of 24% sucrose 2 min prior to all commonly performed painful procedures during their NICU stay. Neurodevelopment was assessed at 18 months of CA using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III). Multiple neonatal and maternal factors known to affect development were adjusted for in the generalised linear model analysis. RESULTS: 172 preterm neonates were enrolled and 118 were included in the analysis at 18 months of CA. The total mean sucrose volume administered/neonate/NICU stay was 5.96 (±5.6) mL, and the mean Bayley-III composite scores were: cognitive 91 (±17), language 86 (±18) and motor 88 (±18). There was no association between Bayley-III scores and the total sucrose volume: cognitive (p=0.57), language (p=0.42) and motor (p=0.70). CONCLUSION: Cumulative sucrose exposure for repeated procedural pain in preterm neonates was neither associated with a delay in neurodevelopment nor neuroprotective effects at 18 months of CA. If sucrose is used, we suggest the minimally effective dose combined with other non-pharmacological interventions with demonstrated effectiveness such as skin-to-skin contact, non-nutritive sucking, facilitated tucking and swaddling. TRIAL REGISTRATION NUMBER: NCT02725814.

Efficacy of intrauterine device procedural analgesics.

ABSTRACT: Nearly half of all pregnancies worldwide are unintended. Intrauterine devices are an effective, long-acting form of pregnancy prevention that require minimal maintenance, and also can be used in patients with menorrhagia. However, they are underused because of pain associated with their insertion. Topical and local anesthesia are good options for reducing procedural pain in select patients. IUD placement falls within the scope of practice for physician associates/assistants (PAs) practicing in family medicine, internal medicine, and women's health. PAs should be aware of these additional analgesia options available to patients in order to increase use of effective contraception.

Nonpharmacological Interventions to Mitigate Procedural Pain in the NICU: An Integrative Review.

BACKGROUND: Small infants experience a myriad of stimuli while in the Neonatal Intensive Care Unit (NICU), with many being painful or stressful experiences, although medically necessary. PURPOSE: To determine what is known about nonpharmacological developmental care interventions used in the NICU to mitigate procedural pain of infants born under 32 weeks gestation. SEARCH/STRATEGY: Five electronic databases were searched: Medline, CINAHL, Scopus, Embase and the Cochrane Library. The inclusion criteria were as follows: experimental and nonexperimental studies from all publication years with infants born at less than 32 weeks gestational age; peer-reviewed research articles studying nonpharmacological interventions such as skin-to-skin care, facilitated tucking, nonnutritive sucking, hand hugs, and swaddling; and English language articles. Our search yielded 1435 articles. After the elimination of 736 duplicates, a further 570 were deemed irrelevant based on their abstract/titles. Then, 124 full-text articles were analyzed with our inclusion and exclusion criteria. FINDINGS: Twenty-seven studies were reviewed. Sucrose, facilitated tucking, pacifier, skin-to-skin care, and human milk appeared to lessen pain experienced during heel sticks, suctioning, nasogastric tube insertions, and echocardiograms. All nonpharmacological interventions failed to prove efficacious to adequately manage pain during retinopathy of prematurity (ROP) examinations. IMPLICATIONS FOR PRACTICE: Evidence review demonstrates that healthcare practitioners should use nonpharmacological measures to help prevent pain from day-to-day procedures in the NICU including heel sticks, nasogastric tube insertions, suctioning, echocardiograms, and subcutaneous injections. IMPLICATIONS FOR RESEARCH: Future research is necessary to better understand and measure how pain is manifested by very small premature infants. Specific research on mitigating the pain of examinations for retinopathy of prematurity is also needed.

Investigating visual preferences of clinical mechanical anesthetic vibration: a cross-sectional image survey.

While mechanical vibration lessens discomfort associated with injection site pain (ISP), many local anesthetic injectors (LAIs) do not use vibratory anesthetic devices (VADs). Injector preference of vibration device is influenced by functional concerns, but qualitatively there is an element of adoption that is driven by visual feedback. We sought to capture operator preferences of vibration device design elements to further understand why injectors do not use these devices. We conducted a survey of image preferences among nurses and medical assistants employed at 8 dermatological clinics to investigate barriers to VAD use. Images were electronically modified with features distinct from the original device (a VAD commonly used in clinical practice). Participants rated their likelihood and comfort of use of each VAD represented in the images. Two-sample t-tests were used to compare the rating of the unmodified VAD to each modified VAD within participants. A response rate of 100% was achieved with 35 participants (average age, 38.5 years; 6 (17.1%) male, 29 (82.9%) female). Despite 28 (80%) participants knowing that mechanical vibration reduces ISP, only 16 (45.7%) endorsed ever using mechanical vibration as topical anesthetic. Images modified by pattern, color, and sterility covering were rated significantly lower than the original, unmodified VAD image (plain white VAD), confirming that visual feedback does impact adoption. Through independent comment categorization, aesthetics were found to be important to LAIs. Aesthetic preferences opposing functional concerns may factor into the lack of VAD use. Defining these visual preference barriers to adoption may help promote VAD use during dermatologic procedures.

Optimizing pediatric periprocedural pain management part I-Evolving ethics and topical anesthetics.

Pediatric procedure-related pain management is often incompletely understood, inadequately addressed, and critical in influencing a child's lifelong relationship with the larger health care community. We highlight the evolution of ethics and expectations around optimizing periprocedural pain management as a fundamental human right. We investigate the state-of-the-art of topical anesthetics, reviewing their mechanisms of action and providing comparisons of their relative safety and efficacy data to help guide clinical selection. In total, this two-part review offers a combination of conventional approaches and innovative techniques that should be used multimodally-in series and in parallel-to help optimize pain management and provide alternatives to sedation medication and general anesthesia.

Virtual Reality Distraction for Needle-Related Pain and Distress in Children: A Multicenter Randomized Controlled Trial.

This international multicenter randomized controlled trial aimed to compare the effectiveness of virtual reality (VR) distraction with an identical non-VR game in reducing needle-related pain and anxiety in children undergoing venous blood draw. The study involved 304 children aged 5-9 years undergoing a blood draw procedure, randomly allocated to one of three groups: VR distraction, non-VR distraction, and control group (usual care). The distraction task was based on the Multiple Object Tracking (MOT) paradigm, and the game was identical in design and gameplay for both VR and non-VR distraction groups. The primary outcome was self-reported pain intensity using the Faces Pain Scale-Revised (FPS-R). Secondary outcomes included child distress, attention/distraction to the blood draw, and parent and medical staff satisfaction with procedure. Analyses were conducted using analysis of variance and multivariable linear regression models. The results showed that VR distraction and non-VR distraction performed similarly, showing large effect sizes compared with standard care. There was no significant difference between the two types of distraction. The study's findings suggest that VR and non-VR distraction are similarly effective in reducing needle-related pain and anxiety in children undergoing venous blood draw. This is the first well-powered study comparing modern VR distraction with an identical task displayed on a smartphone or monitor screen. The study's results have important implications for using VR in clinical settings and suggest that investing in expensive VR equipment for acute pain management may not be necessary. The study protocol was pre-registered on Open Science Framework at https://osf.io/frsyc.

Efficacy of Lidocaine Spray for Pain Reduction during Colposcopy-Directed Cervical Biopsies: A Randomized Controlled Trial.

Objectives: The objective of this study was to evaluate the efficacy of lidocaine spray in reducing the pain during colposcopy-directed cervical biopsy (CDB). Methods: From December 2017 to February 2019, 312 women undergoing CDBs were enrolled. The participants were randomized to three groups: group 1 (lidocaine spray), in which lidocaine spray was applied thoroughly to the cervix; group 2 (placebo), in which normal saline was applied thoroughly to the cervix; and group 3 (control), in which no anesthetic agent was applied to the cervix. Each woman completed a 10 cm visual analog scale to classify the subjective pain experience at three time points: baseline, immediately after biopsy, and 10 min after the procedure. The primary outcome of this study was the biopsy pain score. Results: The 312 enrolled women were randomly assigned to the three groups, amounting to 104 women per group. The clinical and pathological characteristics of the participants in all groups were comparable. The baseline, the biopsy, and the post-procedure pain scores were comparable among the three groups. There was a significant increase in the pain score from baseline to biopsy and from baseline to post-procedure in each group. The pain-score changes from baseline to biopsy in the lidocaine spray group significantly decreased when compared with the normal saline group (<0.001), and tended to decrease, though not significantly (p = 0.06), when compared with the control group. No complication with the intervention was observed. Conclusions: The application of lidocaine spray to the cervix has the benefit of reducing the pain associated with CDBs by a small amount. However, the intervention is safe and may be considered in nulliparous and/or overly anxious women undergoing the procedure.

Effectiveness and safety of Buzzy device in needle-related procedures for children under twelve years of age: A systematic review and meta-analysis.

BACKGROUND: Pain transcends simple physiology, encompassing biological, emotional, psychological, and social facets. Children show pronounced immediate and enduring responses to pain-related procedures. The aim of this meta-analysis is to investigate the efficacy and safety of the Buzzy device for needle-related procedures in children aged twelve years or younger. METHODS: PubMed, Web of Science, and Embase were searched from inception to July 2023. Only randomized controlled trials utilizing the Buzzy device for needle-related procedures in children under twelve years old were included. Two reviewers independently conducted study selection, data extraction, and risk of bias assessment. Random-effects models were utilized, and analyses were performed using mean differences or standardized mean differences as well as risk ratios. RESULTS: A total of 19 studies were included, involving 2846 participants (Buzzy = 1095, Control = 1751). Compared to no intervention, the Buzzy device significantly reduced pain response [self-report SMD = -1.90 (-2.45, -1.36), parental SMD = -3.04 (-4.09, -1.99), observer SMD = -2.88 (-3.75, -2.02)] and anxiety scores [self-report SMD = -1.97 (-3.05, -0.88), parental SMD = -2.01 (-2.93, -1.08), observer SMD = -1.92 (-2.64, -1.19)]. Compared to virtual reality (VR), the Buzzy device reduced self-reported anxiety levels SMD = -0.47 (-0.77, -0.17), and compared to distraction cards, the Buzzy device reduced parental and observer-reported pain [parental SMD = -0.85 (-1.22, -0.48), observer SMD = -0.70 (-1.00, -0.40)] and anxiety [parental SMD = -0.96 (-1.46, -0.47), observer SMD = -0.91 (-1.40, -0.42)]. Subgroup analysis results showed that procedure type, patient age, measurement scales used, and distance of operation were not the reason of heterogeneity. The summarized first puncture attempt success rate did not differ from other interventions. There were no significant adverse events in the included studies. CONCLUSION: The Buzzy device reduces pain and anxiety in children during needle procedures, ensuring success and safety. Additionally, the effectiveness of the Buzzy device in reducing pain during venipuncture is superior when compared to its effectiveness during intramuscular injections.

Effectiveness of Animal-Assisted Activity on Pain Perception and Anxiety of Children Undergoing Intraoral Local Anesthetic Administration.

Purpose: To investigate the impact of animal-assisted activity (AAA) involving a dog (play therapy) on reducing the pain experienced by children during the administration of local anesthetic (LA). Methods: Children between the ages of eight and 12 years who required LA administration were randomized into an AAA group and a control group. Baseline data for the simplified Modified Child Dental Anxiety Scale-Faces version (MCDAS[f]) was recorded, followed by the implementation of either AAA with standard care or standard care alone. The conventional protocol was followed for the administration of LA. Procedural pain was evaluated using both the Faces Pain Scale-Revised (FPS-R) and the Faces, Legs, Activity, Cry, and Consolability Scale (FLACC). All variations in pulse were also recorded. After the procedure, a simplified MCDAS(f) was recorded once again. The data were tabulated and statistically analyzed. Results: The children in the AAA group reported lower pain scores, as measured by FPS-R, compared to the control group (P =0.009). Pain, as observed in the FLACC scores, was also low in the experimental group (P <0.001). A notable reduction in anxiety scores (P <0.001) was observed among children assigned to the AAA group. Conclusion: AAA involving a dog led to a reduction in the pain experienced by children undergoing LA administration, subsequently decreasing anxiety.

The effect of maternal voice and non-nutritional sucking on repeated procedural pain of heel prick in neonates: a quasi-experimental study.

BACKGROUND: Neonates in the neonatal intensive care unit undergo frequent painful procedures. It is essential to reduce pain using safe and feasible methods. PURPOSE: To evaluate the effects of non-nutritional sucking, mother's voice, or non-nutritional sucking combined with mother's voice on repeated procedural pain in hospitalized neonates. METHODS: A quasi-experimental study was conducted in which 141 neonates were selected in a hospital in Changsha, China. Newborns were divided into four groups: non-nutritional sucking (NNS) (n = 35), maternal voice (MV) (n = 35), NNS + MV (n = 34), and control (n = 37) groups. The Preterm Infant Pain Profile-Revised Scale (PIPP-R) was used to assess pain. RESULTS: During the heel prick, the heart rate value and blood oxygen saturation were significantly different between the groups (P < 0.05). Both non-nutritional sucking and maternal voice significantly reduced PIPP-R pain scores of hospitalized newborns (P < 0.05). The pain-relief effect was more robust in the combined group than in other groups. CONCLUSIONS: This study showed that both non-nutritional sucking and the mother's voice alleviated repeated procedural pain in neonates. Therefore, these interventions can be used as alternatives to reduce repeated procedural pain.

Virtual Reality for the Management of Pain and Anxiety for IR Procedures: A Prospective, Randomized, Pilot Study on Digital Sedation.

PURPOSE: To assess the analgesic and anxiolytic effects of virtual reality (VR) augmentation in patients undergoing peripherally inserted central catheter (PICC) placement or fine-needle aspiration thyroid biopsy. MATERIALS AND METHODS: This is a prospective, single-center randomized controlled trial with 107 patients enrolled. Patients were randomly assigned to receive standard of care (SOC) or SOC+VR during PICC or thyroid biopsy procedures. Pain and anxiety were individually measured using the visual analog scale (VAS) before and after the procedure. Vital signs including heart rate and systolic and diastolic blood pressure were recorded. One-way analysis of variance test and Games-Howell post hoc analysis were used to assess effect size and statistical significance between SOC and SOC+VR measures. RESULTS: The PICC cohort consisted of 59 patients (33 in SOC+VR and 26 in SOC), with a median age of 53.1 years (interquartile range [IQR], 38.3-62.7 years). The thyroid biopsy cohort consisted of 48 patients (26 in SOC+VR and 22 in SOC), with a median age of 60.1 years (IQR, 49.0-67.2 years). One-way analysis of individuals undergoing thyroid biopsies with adjunctive VR revealed an effect size of -1.74 points (SE ± 0.71; P = .018) on VAS pain scale when compared with SOC. Analysis of individuals undergoing PICC placements revealed an effect size of -1.60 points (SE ± 0.81; P = .053) on VAS anxiety when compared with SOC. CONCLUSIONS: VR as a nonpharmacologic adjunct reduced some procedure-related pain and anxiety without increasing the procedural duration.

Effect of photobiomodulation therapy on pain perception during anesthetic puncture of dental local anesthesia: A systematic review.

BACKGROUND: Local anesthetic puncture is often related to the experience of pain. This study aimed to systematically analyze the literature on changes in pain perception during the anesthetic puncture of dental local anesthesia after Photobiomodulation Therapy (PBMT). MATERIAL AND METHODS: An electronic search was performed in eight primary databases (Embase, LILACS, BBO, LIVIVO, MedLine via PubMed, SciELO, Scopus, and Web of Science) and three additional ones (EASY, Google Scholar, and OATD) to partially capture the "gray literature". The PICO strategy was used to identify randomized clinical trials evaluating the analgesic effect of PBMT in the anesthetic puncture site of dental local anesthesia compared to placebo or control groups, without restrictions on publication language and year. Two reviewers extracted the data and assessed the individual risk of bias of the eligible studies using the Cochrane Collaboration Risk of Bias Tool version 2.0. RESULTS: The electronic search found 3,485 records, of which eight met the eligibility criteria and were included in the qualitative synthesis. The studies were published from 2011 to 2022. None of the included studies had a low risk of bias. PBMT groups showed no significant difference in pain scores compared to placebo and control groups of most studies. CONCLUSION: Based on a low to very low certainty of evidence, PBMT seems to have no effect on pain perception during anesthetic puncture in patients undergoing dental local anesthesia.

Evaluation of thermal shock therapy for reducing pain during intense pulsed light therapy: An intrapatient randomized controlled study.

BACKGROUND: Intense pulsed light (IPL) is used for the treatment and improvement of various skin issues. However, patients often experience local skin burning and pain after IPL treatment. Cooling and analgesic measures are indispensable. AIMS: To investigate the clinical effect of thermal shock therapy on pain relief and reduction of adverse reactions during IPL therapy. PATIENTS/METHODS: A total of 60 female patients with facial photoaging who received IPL therapy were enrolled in the study. As a comparative split-face study, one side of the face was randomly selected as the control side. The other side was given thermal shock therapy before and after the IPL treatment immediately as analgesic side. The visual analog scale (VAS) was used to evaluate the pain degree of the patients. The telephone follow-ups regarding the occurrence of adverse reactions were conducted respectively on the 2nd day, 7th day, and 1 month after treatment. RESULTS: The VAS score and skin temperature of analgesia side was lower than that of control side at different stages of treatment. In terms of adverse reactions, the incidence of transient facial redness on the analgesic side was lower than that on the control side. Two patients showed slight secondary pigmentation on the control side, and the other patients showed no other adverse reactions on both sides. CONCLUSIONS: Thermal shock therapy assisted IPL therapy can reduce skin temperature during treatment, effectively relieve patients' pain, reduce the occurrence of adverse reactions caused by heat injury, and improve patients' comfort level.

Repetitive neonatal procedural pain affects stress-induced plasma corticosterone increase in young adult females but not in male rats.

Exposure to repetitive painful procedures in the neonatal intensive care unit results in long-lasting effects, especially visible after a "second hit" in adulthood. As the nociceptive system and the hypothalamic-pituitary-adrenal (HPA) axis interact and are vulnerable in early life, repetitive painful procedures in neonates may affect later-life HPA axis reactivity. The first aim of the present study was to investigate the effects of repetitive neonatal procedural pain on plasma corticosterone levels after mild acute stress (MAS) in young adult rats. Second, the study examined if MAS acts as a "second hit" and affects mechanical sensitivity. Fifty-two rats were either needle pricked four times a day, disturbed, or left undisturbed during the first neonatal week. At 8 weeks, the animals were subjected to MAS, and plasma was collected before (t0), after MAS (t20), and at recovery (t60). Corticosterone levels were analyzed using an enzyme-linked immunosorbent assay, and mechanical sensitivity was assessed with von Frey filaments. Results demonstrate that repetitive neonatal procedural pain reduces stress-induced plasma corticosterone increase after MAS only in young adult females and not in males. Furthermore, MAS does not affect mechanical sensitivity in young adult rats. Altogether, the results suggest an age- and sex-dependent effect of repetitive neonatal procedural pain on HPA axis reprogramming.