Pain and respiration: a systematic review

Cyclic sighing in the clinic waiting room may decrease pain: results from a pilot randomized controlled trial

Pain is a common medical experience, and patient access to pain management could be improved with novel intervention formats. Emerging evidence indicates brief, asynchronous, single-session interventions delivered in the clinic waiting room can improve patient outcomes, but only a few treatment modalities have been investigated to date. Breathwork is a promising approach to managing acute clinical pain that could be delivered asynchronously in the clinic waiting room. However, the direct impact of a breathwork intervention (e.g., brief cyclic sighing) on patients' pain and psychological distress (e.g., anxiety and depression symptoms) while waiting in the clinic waiting room remains unexamined. This single-site, pilot, randomized controlled trial examined the impact of a 4-minute, asynchronous, cyclic sighing intervention on participants' acute clinical symptoms in the x-ray waiting room of a walk-in orthopedic clinic relative to a time- and attention-matched injury management control condition. Pain unpleasantness, pain intensity, anxiety symptoms, and depression symptoms were measured in the study. Participants receiving the cyclic sighing intervention reported significantly less pain unpleasantness and pain intensity while waiting for an x-ray relative to controls. Anxiety symptoms and depression symptoms were not found to differ by condition. Results from this RCT indicate a brief, asynchronous, cyclic sighing intervention may be capable of quickly decreasing pain in the waiting room. Continued investigation is now needed to determine if embedding brief, asynchronous, cyclic sighing interventions in clinic waiting rooms has the potential to help people experiencing acute pain feel better faster. CLINICAL TRIAL REGISTRATIONS: NCT06292793.

A Digital Program for Daily Life Management With Endometriosis: Pilot Cohort Study on Symptoms and Quality of Life Among Participants

BACKGROUND

After experiencing symptoms for an average of 7 years before diagnosis, patients with endometriosis are usually left with more questions than answers about managing their symptoms in the absence of a cure. To help women with endometriosis after their diagnosis, we developed a digital program combining user research, evidence-based medicine, and clinical expertise. Structured around cognitive behavioral therapy and the quality of life metrics from the Endometriosis Health Profile score, the program was designed to guide participants for 3 months.

OBJECTIVE

This cohort study was designed to measure the impact of a digital health program on the symptoms and quality of life levels of women with endometriosis.

METHODS

In total, 63% (92/146) of the participants were included in the pilot study, recruited either free of charge through employer health insurance or via individual direct access. A control group of 404 women with endometriosis who did not follow the program, recruited through social media and mailing campaigns, was sampled (n=149, 36.9%) according to initial pain levels to ensure a similar pain profile to participants. Questionnaires assessing quality of life and symptom levels were emailed to both groups at baseline and 3 months. Descriptive statistics and statistical tests were used to analyze intragroup and intergroup differences, with Cohen d measuring effect sizes for significant results.

RESULTS

Over 3 months, participants showed substantial improvements in global symptom burden, general pain level, anxiety, depression, dysmenorrhea, dysuria, chronic fatigue, neuropathic pain, and endo belly. These improvements were significantly different from the control group for global symptom burden (participants: mean -0.7, SD 1.6; controls: mean -0.3, SD 1.3; P=.048; small effect size), anxiety (participants: mean -1.1, SD 2.8; controls: mean 0.2, SD 2.5; P<.001; medium effect size), depression (participants: mean -0.9, SD 2.5; controls: mean 0.0, SD 3.1; P=.04; small effect size), neuropathic pain (participants: mean -1.0, SD 2.7; controls: mean -0.1, SD 2.6; P=.004; small effect size), and endo belly (participants: mean -0.9, SD 2.5; controls: mean -0.3, SD 2.4; P=.03; small effect size). Participants' quality of life improved between baseline and 3 months and significantly differed from that of the control group for the core part of the Endometriosis Health Profile-5 (participants: mean -5.9, SD 21.0; controls: mean 1.0, SD 14.8; P=.03; small effect size) and the EQ-5D (participants: mean 0.1, SD 0.1; controls: mean -0.0, SD 0.1; P=.001; medium effect size). Perceived knowledge of endometriosis was significantly greater at 3 months among participants compared to the control group (P<.001).

CONCLUSIONS

This study's results suggest that a digital health program providing medical and scientific information about endometriosis and multidisciplinary self-management tools may be useful to reduce global symptom burden, anxiety, depression, neuropathic pain, and endo belly while improving knowledge on endometriosis and quality of life among participants.

Diaphragm Fatigue Does Not Impact Breathing Mechanics or Function in People with Chronic Low Back Pain

Background and Objective

The diaphragm is an important respiratory muscle that also plays a crucial role in developing intra-abdominal pressure and assisting in spinal stability. Chronic low back pain (CLBP) is a complex musculoskeletal condition and has been associated with respiratory problems and altered breathing mechanics. The purpose of this comparative cross-sectional study is to investigate whether diaphragm fatigue affects breathing mechanics and function in individuals with CLBP.

Methods

Volunteers were recruited between the ages of 35-65 years old with and without CLBP. Participants performed 30 minutes of exercises intended to fatigue the diaphragm. The following respiratory parameters were measured: Breathing mechanics (chest and abdominal movement and respiratory rate), diaphragm function (forced expiratory volume in 1 second (FEV1) using a handheld spirometer), and diaphragm movement as measured by sub-diaphragm (L1 to diaphragm domes) volume changes at the end of exhalation and inhalation using MRI scans.

Results

A total of 36 participants were recruited (n = 21M; n = 15F), with 18 participants suffering from CLBP (n = 10M; 8F) and 18 participants serving as a comparison group (n = 11M; n = 7F). There were no differences in breathing mechanics, diaphragm function or excursion (volumetrics) between people with and without CLBP after 30 minutes of exercises intended to fatigue the diaphragm.

Conclusion

The lack of differences suggests that the diaphragm, regardless of its fatigue status as a spinal stabilizer, will not relinquish or weaken its function as a breathing muscle, though it may be less effective as a spinal stabilizer. Individuals with chronic or recurrent low back pain might therefore be more susceptible to subsequent pain flare-ups than non-symptomatic individuals. A potential clinical implication of these findings is that incorporating diaphragmatic breathing exercises to enhance diaphragm function may offer an effective treatment option for patients with CLBP.

Effects of cipepofol on breathing patterns, respiratory drive, and inspiratory effort in mechanically ventilated patients

Background

Cipepofol is a highly selective gamma-aminobutyric acid A receptor potentiator. As a new sedative drug, detailed studies on its respiratory effects are further needed. The present study aims to investigate the effects of cipepofol on breathing patterns, respiratory drive, and inspiratory effort in mechanically ventilated patients.

Methods

In this one-arm physiological study, cipepofol was initiated at 0.3 mg/kg/h and increased by 0.1 mg/kg/h every 30 min until reaching 0.8 mg/kg/h. Discontinuation criteria were Richmond Agitation and Sedation Scale (RASS) score ≤ -4 or respiratory rate (RR) < 8 breaths/min or pulse oxygen saturation (SpO2) < 90%. The primary outcomes were changes from baseline in respiratory variables [RR, tidal volume (VT), minute ventilation (Vmin), airway occlusion pressure at 100 msec (P0.1), pressure muscle index (PMI), expiratory occlusion pressure (Pocc)] at 30 min after 0.3 mg/kg/h cipepofol infusion. The secondary outcomes included changes in respiratory variables, cardiorespiratory variables, and RASS scores at rates of cipepofol from 0.3 to 0.8 mg/kg/h.

Results

20 patients were enrolled and all of them completed the cipepofol infusion rate at 0.3 mg/kg/h, achieving RASS score of -2 to +1. For the primary outcomes, there was a significant reduction in VT (390.9, [356.6-511.0] vs. 451.6 [393.5-565.9], p = 0.002), while changes in RR (16.7 ± 2.7 vs. 16.2 ± 3.4, p = 0.465) and Vmin (7.2 ± 1.8 vs. 7.5 ± 1.9, p = 0.154) were not significant. The reductions in P0.1 (p = 0.020), PMI (p = 0.019), and Pocc (p = 0.007) were significant. For secondary outcomes, as the infusion rate of cipepofol increased from 0.3 to 0.8 mg/kg/h, there was a further decrease in VT (p = 0.002) and an increase in RR (p < 0.001), while the change in Vmin (p = 0.430) was not significant. RASS score (p < 0.001) was further decreased.

Conclusion

Cipepofol demonstrates the capability to achieve RASS score -2 to +1 in mechanically ventilated adult patients. The effect of cipepofol on breathing patterns was a decrease in VT, while changes in RR and Vmin were insignificant. The effect on respiratory drive and inspiratory effort significantly reduced P0.1, PMI, and Pocc.

Clinical trial registration

ClinicalTrials.gov, identifier NCT06287138. https://clinicaltrials.gov/study/NCT06287138.

Exploratory Ultrasound Analysis of the Diaphragm and Respiratory Capacity in Women with Primary Dysmenorrhea: A Cross-Sectional Observational Study

Primary dysmenorrhea (PD) is a common gynecological condition characterized by menstrual pain without underlying pelvic pathology. It has been linked to functional and structural changes in the core musculature, but limited evidence exists regarding its association with diaphragmatic and respiratory mechanics. This study aimed to elaborate on these potential associations by assessing the diaphragmatic structure and respiratory function in women with PD compared to healthy controls, utilizing ultrasound imaging, spirometry and respiratory pressure measurements.

METHODS

An observational, cross-sectional study was conducted with 44 female participants (22 with PD and 22 healthy controls). Diaphragmatic structure was evaluated through ultrasound, measuring the intercostal distance, diaphragmatic thickness, and diaphragmatic excursion at rest and during maximum voluntary contraction. Spirometric assessments included forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), and the FVC/FEV1 ratio, along with measurements of maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP). Group differences were analyzed using Student's t-test and effect sizes were reported with Cohen's d.

RESULTS

No significant differences were observed between the groups in diaphragmatic thickness, diaphragmatic excursion, or global respiratory capacity (p > 0.05). However, women with PD presented a significant reduction in the left intercostal distance both at rest (p = 0.035, d = 0.56) and during contraction (p = 0.039, d = 0.54). No other significant group differences were detected.

CONCLUSIONS

While primary dysmenorrhea does not appear to affect overall diaphragmatic function or respiratory capacity, it is associated with subtle localized changes in the left intercostal dynamics. These findings suggest a potential compensatory mechanical adaptation rather than global respiratory dysfunction. Further longitudinal studies with larger sample sizes are needed to explore the clinical significance of these findings.

Examining the impact of rhythmic breathing and progressive muscle relaxation on acute pain following inguinal hernia repair: a parallel randomized clinical trial

BACKGROUND

Acute postoperative pain is often reported after repair of inguinal hernia and can negatively impact patient satisfaction and clinical outcomes. This includes delayed wound healing, longer hospitalization, and increased health care costs. Non-pharmacological techniques like Progressive Muscle Relaxation (PMR) and Rhythmic Breathing (RB) have been suggested as possible interventions for managing this type of pain. The purpose of this study was to examine the effects of PMR and RB on postoperative pain following repair of inguinal hernia.

METHODS

This parallel randomized controlled trial was conducted to examine 120 patients in the age range of 18 to 75 years with inclusion criteria: Repair of Inguinal Hernia under general anesthesia and no addiction to drugs and narcotics. These patients were randomly assigned to one of three groups: the RB group, PMR group, or the control group (which received standard care). The RB and PMR interventions were administered at 3, 6, 12, and 24 h after surgery. The primary outcome measure was the intensity of pain at the surgical site, assessed using the Visual Analog Scale (VAS). The secondary outcome measure was the amount of rescue analgesic (Pethidine). The one-way analysis of variance, Chi-square, post-hoc test, and repeated measures ANOVA were used for data analysis.

RESULTS

Following the interventions, participants in both the RB and PMR groups exhibited significantly lower levels of acute pain after inguinal hernia repair compared to the control group across all four time periods, except at 12 h postoperatively in the RB group. However, there was no statistically significant difference between the RB and PMR groups. Additionally, the amount of pethidine consumed in the control group was significantly higher compared to the two experimental groups.

CONCLUSIONS

Based on the results, both RB and PMR were found to be effective techniques in reducing patients' pain. Therefore, it is recommended that healthcare team members, particularly nurses, actively learn and teach both RB and PMR.

TRIAL REGISTRATION

Registered in the Iranian registry of clinical trials ( www.irct.ir ) in 31/01/2023 with the following code: IRCT20200206046395N2.

Supraspinal glycinergic neurotransmission in pain: A scoping review of current literature

The neurotransmitter glycine is an agonist at the strychnine-sensitive glycine receptors. In addition, it has recently been discovered to act at two new receptors, the excitatory glycine receptor and metabotropic glycine receptor. Glycine's neurotransmitter roles have been most extensively investigated in the spinal cord, where it is known to play essential roles in pain, itch, and motor function. In contrast, less is known about supraspinal glycinergic functions, and their contributions to pain circuits are largely unrecognized. As glycinergic neurons are absent from cortical regions, a clearer understanding of how supraspinal glycine modulates pain could reveal new pharmacological targets. This review aims to synthesize the published research on glycine's role in the adult brain, highlighting regions where glycine signaling may modulate pain responses. This was achieved through a scoping review methodology identifying several key regions of supraspinal pain circuitry where glycine signaling is involved. Therefore, this review unveils critical research gaps for supraspinal glycine's potential roles in pain and pain-associated responses, encouraging researchers to consider glycinergic neurotransmission more widely when investigating neural mechanisms of pain.

Mindful Breathing as an Adjunctive Approach to Chronic Low Back Pain Management: A Scoping Review

BACKGROUND

Chronic low back pain (CLBP) is a common and challenging condition. This scoping review explores the literature on mindful breathing's role in managing CLBP, either alone or alongside physiotherapy.

METHODS

A thorough database search identified studies on mindful breathing and CLBP. Various study designs, from descriptive to randomized controlled trials, were included.

RESULTS

Reviewed studies suggest that mindful breathing can improve body awareness and patients with CLBP. In a randomized controlled trial both mindful breathing and physiotherapy groups reported significant pain reduction (VAS: -2.7 mindful breathing, VAS: -2.4 physiotherapy) and improved quality of life (SF-36*: +14.9 mindful breathing, SF-36: +21.0 physiotherapy). Yu et al. found that combining mindful breathing with core stability exercises yielded superior outcomes (ORR* = 96.67%) compared to core exercises alone (ORR = 73.33%).

CONCLUSIONS

Mindful breathing holds promise for chronic low back pain management, with studies revealing pain reduction and improved quality of life. Combining it with core stability exercises enhances outcomes. However, standardized protocols are lacking, limiting clinical use. Future research should focus on precise guidelines for integration into practice. Mindful breathing offers a holistic approach to pain management.

An evidence-based breathing exercise intervention for chronic pain management in breast cancer survivors: A phase II randomized controlled trial

OBJECTIVE

Explore the preliminary effects of a breathing exercise (BE) intervention on chronic pain among breast cancer survivors.

METHODS

This two-parallel-arm, open-label pilot randomized controlled trial recruited 72 breast cancer survivors who were randomly allocated to either the control or intervention group (n = 36 each). Both groups received usual care and a pain information booklet, while the intervention group received 4 weeks of additional BE. The primary clinical outcome was measured using the Brief Pain Inventory (BPI), with secondary clinical outcomes measured by the Hospital Anxiety and Depression Scale (HADS), Quality of Life Patient/Cancer Survivor Version in Chinese (QOLCSV-C), and Functional Assessment of Cancer Therapy- Breast (FACT-B) immediately post-intervention and at 4-week follow-up. Both adjusted and unadjusted Generalized Estimating Equation models were utilized to assess the BE's potential effects, with safety assessed through participant self-report.

RESULTS

Sixty-eight participants completed the study. Statistical significance was observed in BPI in both adjusted and unadjusted models at post-intervention and follow-up (p < 0.05). BE demonstrated positive effects on anxiety, depression and quality of life improvement across all measures and timepoints in both adjusted and unadjusted models (p < 0.05). The effect sizes were smaller in the adjusted model. Three mild transient discomforts were reported associated with BE practice including dizziness, tiredness and yawning, without requirement of medical treatment. No severe adverse events occurred.

CONCLUSION

This BE intervention appears effective in alleviating chronic pain, anxiety and depression, and improving quality of life for breast cancer survivors. Fully powered large-scale studies are required to confirm its effects.

Respiratory dysfunction in persistent somatic symptoms: A systematic review of observational studies

OBJECTIVE

This systematic review aims to analyze the existing literature investigating respiratory functioning in people with Persistent Somatic Symptoms (PSS) compared to healthy controls, to identify patterns of respiratory disturbances by symptom or syndrome, and describe any respiratory outcomes consistent across diagnoses.

METHODS

A systematic review following PRISMA guidelines was conducted. A comprehensive search was carried out across five databases (PubMed (NCBI), PsycArticles (Ovid), Web of Science (Core Collection), Embase, and Scopus) using two customised search strings for persistent somatic symptoms and objective respiratory parameters. Title/abstract screening and data extraction were carried out independently by two reviewers. The modified Newcastle-Ottawa Scale was used for quality assessment of the studies. Studies investigating baseline respiratory functioning in adult patients with PSS compared to healthy controls, using at least one objective respiratory were included.

RESULTS

18 studies met the inclusion criteria for the review, with a pooled sample size of n = 3245. Chronic pain conditions were found to be the most prevalent subset of diagnoses of interest, comprising six of the studies. 10 studies included measures of lung capacity, flow and/or volume, nine studies reported measures of ventilation, and four studies investigated respiratory muscle functioning. 13 of the included studies reported significant differences in at least one objective respiratory measure between groups (at rest). Scores on self-reported measures of dysnpea and breathlessness were higher in patients compared to healthy controls, while objective respiratory outcomes were varied.

CONCLUSION

The current systematic review is consistent with previous literature suggesting more pronounced experiences of breathlessness in patients with PSS, and significant disparities between reported dyspnea and objective respiratory outcomes. Research investigating the uncoupling between subjective and objective respiratory outcomes is needed to understand the mechanisms behind breathing disturbances in PSS.

Designing and developing a nature-based virtual reality with heart rate variability biofeedback for surgical anxiety and pain management: evidence from total knee arthroplasty patients

OBJECTIVES

Total knee arthroplasty (TKA) is one of the most common joint surgeries, with over a million procedures performed annually in the US. Over 70% of patients report moderate to high pain and anxiety surrounding TKA surgery, and 96% are discharged with an opioid prescription. This population requires special attention as approximately 90% of TKA patients are older adults and one of the riskiest groups prone to misusing opioids. This study aimed to develop and compare the efficacy of nature-based virtual reality (VR) with heart rate variability biofeedback (HRVBF) to mitigate surgical pain and anxiety.

METHODS

This randomized control trial recruited 30 patients (mean age = 66.3 ± 8.2 years, 23 F, 7 M) undergoing TKA surgery and randomly assigned to a control, 2D video with HRVBF, or VR with HRVBF group. A visual analog scale (VAS) was used to measure pain levels before and after the intervention. In addition, a second VAS and the State-Trait Anxiety Inventory (STAI) were used to measure anxiety before and after the intervention. Electrocardiogram (ECG) was used to continuously measure HRV and respiration rate in preoperative and postoperative settings.

RESULTS

VR and 2D-video with HRVBF decreased pain and anxiety post-intervention compared with the control group, p's <.01. On analyzing physiological signals, both treatment groups showed greater parasympathetic activity levels, and VR with HRVBF reduced pain more than the 2D video, p < .01.

CONCLUSIONS

Nature-based VR and 2D video with HRVBF can mitigate surgical pain and anxiety. However, VR may be more efficacious than 2D video in reducing pain.

Comparing multimodal physiological responses to social and physical pain in healthy participants

Background

Previous physiology-driven pain studies focused on examining the presence or intensity of physical pain. However, people experience various types of pain, including social pain, which induces negative mood; emotional distress; and neural activities associated with physical pain. In particular, comparison of autonomic nervous system (ANS) responses between social and physical pain in healthy adults has not been well demonstrated.

Methods

We explored the ANS responses induced by two types of pain-social pain, associated with a loss of social ties; and physical pain, caused by a pressure cuff-based on multimodal physiological signals. Seventy-three healthy individuals (46 women; mean age = 20.67 ± 3.27 years) participated. Behavioral responses were assessed to determine their sensitivity to pain stimuli. Electrocardiogram, electrodermal activity, photoplethysmogram, respiration, and finger temperature (FT) were measured, and 12 features were extracted from these signals.

Results

Social pain induced increased heart rate (HR) and skin conductance (SC) and decreased blood volume pulse (BVP), pulse transit time (PTT), respiration rate (RR), and FT, suggesting a heterogeneous pattern of sympathetic-parasympathetic coactivation. Moreover, physical pain induced increased heart rate variability (HRV) and SC, decreased BVP and PTT, and resulted in no change in FT, indicating sympathetic-adrenal-medullary activation and peripheral vasoconstriction.

Conclusion

These results suggest that changes in HR, HRV indices, RR, and FT can serve as markers for differentiating physiological responses to social and physical pain stimuli.

Development of an Acute Pain Assessment Tool for Patients in Post-anesthesia Care Units

BACKGROUND

Post-operative pain is a common form of acute pain. Objective pain assessment in post-anesthesia care units after surgery is useful regardless of the patient's condition.

AIMS

This study aimed to develop and evaluate an acute pain assessment tool for patients in post-anesthesia care units.

DESIGN

This was a cross-sectional observational study comprising two stages: scale development and psychometric evaluation.

SETTINGS

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PARTICIPANTS/SUBJECTS

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METHODS

Scale items were developed based on a literature review and content validity by experts. The validity and interrater reliability of the pain scale were evaluated using data from 218 patients admitted to the post-anesthesia care unit at a university hospital. A receiver operating characteristic curve was used to identify the sensitivity and specificity for determining the cutoff point for acute pain.

RESULTS

We developed an objective acute pain scale, called the APA5, which ranges from 0-10 and comprises behavioral (facial and verbal expressions and body movement) and physiological (changes in heart rate and blood pressure) responses. The APA5 is valid and reliable for assessing acute pain in the recovery room. Sensitivity and specificity were acceptable when the cutoff was 2 out of 10 points.

CONCLUSIONS

The APA5 is an easy and simple tool for measuring pain in patients in post-anesthesia care units who have difficulties with self-reporting.

To what degree patient-reported symptoms of central sensitization, kinesiophobia, disability, sleep, and life quality associated with 24-h heart rate variability and actigraphy measurements?

OBJECTIVES

Chronic musculoskeletal pain is associated with decreased parasympathetic and increased sympathetic activity in the autonomic nervous system. The objective of this study was to determine the associations between objective measures of heart rate variability (a measure of autonomic nervous system function), actigraphy (a measure of activity and sleep quality), respiration rates, and subjective patient-reported outcome measures (PROMs) of central sensitization, kinesiophobia, disability, the effect of pain on sleep, and life quality.

METHODS

Thirty-eight study subjects were divided into two subgroups, including low symptoms of central sensitization (n = 18) and high symptoms of central sensitization (n = 20), based on patient-reported scores on the Central Sensitization Inventory (CSI). Heart rate variability (HRV) and actigraphy measurements were carried out simultaneously in 24 h measurement during wakefulness and sleep.

RESULTS

A decrease in HRV during the first 2 h of sleep was stronger in the low CSI subgroup compared to the high CSI subgroup. Otherwise, all other HRV and actigraphy parameters and subjective measures of central sensitization, disability, kinesiophobia, the effect of pain on sleep, and quality of life showed only little associations.

DISCUSSION

The high CSI subgroup reported significantly more severe symptoms of disability, kinesiophobia, sleep, and quality of life compared to the low CSI subgroup. However, there were only small and nonsignificant trend in increased sympathetic nervous system activity and poorer sleep quality on the high central sensitization subgroup. Moreover, very little differences in respiratory rates were found between the groups.

Breathing Right… or Left! The Effects of Unilateral Nostril Breathing on Psychological and Cognitive Wellbeing: A Pilot Study

The impact of controlled breathing on cognitive and affective processing has been recognized since ancient times, giving rise to multiple practices aimed at achieving different psychophysical states, mostly related to mental clarity and focus, stress reduction, and relaxation. Previous scientific research explored the effects of forced unilateral nostril breathing (UNB) on brain activity and emotional and cognitive functions. Some evidence concluded that it had a contralateral effect, while other studies presented controversial results, making it difficult to come to an unambiguous interpretation. Also, a few studies specifically addressed wellbeing. In the present study, we invited a pilot sample of 20 participants to take part in an 8-day training program for breathing, and each person was assigned to either a unilateral right nostril (URNB) or left nostril breathing condition (ULNB). Then, each day, we assessed the participants' wellbeing indices using their moods and mind wandering scales. The results revealed that, after the daily practice, both groups reported improved wellbeing perception. However, the effect was specifically related to the nostril involved. URNB produced more benefits in terms of stress reduction and relaxation, while ULNB significantly and increasingly reduced mind-wandering occurrences over time. Our results suggest that UNB can be effectively used to increase wellbeing in the general population. Additionally, they support the idea that understanding the effects of unilateral breathing on wellbeing and cognition requires a complex interpretive model with multiple brain networks to address bottom-up and top-down processes.

Differences of diaphragmatic muscle contraction between female patients with chronic neck pain and asymptomatic controls: A case-control study based on ultrasonography

BACKGROUND

Recent systematic reviews and meta-analyses show that individuals with chronic neck pain (CNP) have altered respiratory muscle strength and abnormal respiratory mechanics. However, no study has investigated the diaphragmatic function in individuals with CNP compared to asymptomatic peers.

OBJECTIVES

This study aimed to compare the respiratory muscle strength and diaphragmatic function between patients with CNP and asymptomatic controls.

DESIGN

Observational, case-control study.

METHODS

A total of 25 women with CNP and 23 asymptomatic controls participated in this case-control study. The visual analog scale and neck disability index were used to assess the pain and disability characteristics of the CNP group. Maximum inspiratory and expiratory pressures (MIP and MEP) were measured to determine respiratory muscle strengths. The diaphragmatic function (muscle thickness in deep inspiration, Tins; and at the end of calm expiration, Texp; muscle thickness change, ΔT; contraction ratio, CR) were evaluated by two-dimensional ultrasonography.

RESULTS

The MIP (p = 0.001, d = 1.11), ΔT (p = 0.033, d = 0.63), and CR (p = 0.012, d = 0.75) of the diaphragm were found significantly reduced in the CNP group compared to asymptomatic controls whilst MEP, Tins, and Texp of the diaphragm were similar between study groups (p > 0.05). The intensity of neck pain was moderately correlated with MIP (r = -0.48), Tins (r = -0.46), and ΔT (r = -0.42) while NDI (r = -0.42) had a moderate correlation with Tins (p < 0.05).

CONCLUSION

The present findings revealed that women with CNP have altered diaphragmatic function. Thus, screening and targeting diaphragm may improve the rehabilitation process in CNP. However, further experimental studies regarding the efficacy of breathing exercise approaches are needed.

Hypocapnia in women with fibromyalgia

OBJECTIVES

The purpose of this study was to investigate whether people with fibromyalgia (FM) have dysfunctional breathing by examining acid-base balance and comparing it with healthy controls.

METHODS

Thirty-six women diagnosed with FM and 36 healthy controls matched for age and gender participated in this cross-sectional study. To evaluate acid-base balance, arterial blood was sampled from the radial artery. Carbon dioxide, oxygen, bicarbonate, base excess, pH and lactate were analysed for between-group differences. Blood gas analyses were performed stepwise on each individual to detect acid-base disturbance, which was categorized as primary respiratory and possible compensation indicating chronicity. A three-step approach was employed to evaluate pH, carbon dioxide and bicarbonate in this order.

RESULTS

Women with FM had significantly lower carbon dioxide pressure (p = 0.013) and higher lactate (p = 0.038) compared to healthy controls at the group level. There were no significant differences in oxygen pressure, bicarbonate, pH and base excess. Employing a three-step acid-base analysis, 11 individuals in the FM group had a possible renally compensated mild chronic hyperventilation, compared to only 4 among the healthy controls (p = 0.042).

CONCLUSIONS

In this study, we could identify a subgroup of individuals with FM who may be characterized as mild chronic hyperventilators. The results might point to a plausible dysfunctional breathing in some women with FM.

The effect of doxapram on survival and APGAR score in newborn puppies delivered by elective caesarean: A randomized controlled trial

Doxapram is marketed as a respiratory stimulant and is used by some veterinarians to help with neonatal apnoea, especially in puppies delivered by caesarean. There is a lack of consensus as to whether the drug is effective and data on its safety are limited. Doxapram was compared to placebo (saline) in newborn puppies in a randomized, double-blinded clinical trial using two outcome measures: 7-day mortality rate and repeated APGAR score measurements. Higher APGAR scores have been positively correlated with survival and other health outcomes in newborns. Puppies were delivered by caesarean and a baseline APGAR score was measured. This was immediately followed by a randomly allocated intralingual injection of either doxapram or isotonic saline (of the same volume). Injection volumes were determined by the weight of the puppy and each injection was administered within a minute of birth. The mean dose of doxapram administered was 10.65 mg/kg. APGAR scores were measured again at 2, 5, 10 and 20 min. One hundred and seventy-one puppies from 45 elective caesareans were recruited into this study. Five out of 85 puppies died after receiving saline and 7 out of 86 died after receiving doxapram. Adjusting for the baseline APGAR score, the age of the mother and whether the puppy was a brachycephalic breed, there was insufficient evidence to conclude a difference in the odds of 7-day survival for puppies that received doxapram compared to those that received saline (p = .634). Adjusting for the baseline APGAR score, the weight of the mother, the litter size, the mother's parity number, the weight of the puppy and whether the puppy was a brachycephalic breed, there was insufficient evidence to conclude a difference in the probability of a puppy having an APGAR score of ten (the maximum APGAR score) between those that received doxapram compared to those that received saline (p = .631). Being a brachycephalic breed was not associated with an increased odds of 7-day mortality (p = .156) but the effect of the baseline APGAR score on the probability of having an APGAR score of ten was higher for brachycephalic than non-brachycephalic breeds (p = .01). There was insufficient evidence that intralingual doxapram provided an advantage (or disadvantage) compared to intralingual saline when used routinely in puppies delivered by elective caesarean and that were not apnoeic.

Assessment and management of pelvic fractures from high-energy trauma in adults

Pelvic fractures caused by high-energy trauma such as falling from a height or road traffic collisions have a high mortality rate and patients are also at high risk of life-changing injuries. High-energy trauma to the pelvis is associated with major haemorrhage and injuries to the internal pelvic organs. Emergency nurses have a fundamental role in the initial assessment and management of patients, as well as in their ongoing care once the fracture has been stabilised and bleeding is controlled. This article describes the anatomy of the pelvis, discusses the initial assessment and management of patients who have sustained high-energy pelvic trauma, details the complications of pelvic fractures and explains patients' ongoing care in the emergency department.

Objective Measurement of Subjective Pain Perception with Autonomic Body Reactions in Healthy Subjects and Chronic Back Pain Patients: An Experimental Heat Pain Study

Multiple attempts to quantify pain objectively using single measures of physiological body responses have been performed in the past, but the variability across participants reduces the usefulness of such methods. Therefore, this study aims to evaluate whether combining multiple autonomic parameters is more appropriate to quantify the perceived pain intensity of healthy subjects (HSs) and chronic back pain patients (CBPPs) during experimental heat pain stimulation. HS and CBPP received different heat pain stimuli adjusted for individual pain tolerance via a CE-certified thermode. Different sensors measured physiological responses. Machine learning models were trained to evaluate performance in distinguishing pain levels and identify key sensors and features for the classification task. The results show that distinguishing between no and severe pain is significantly easier than discriminating lower pain levels. Electrodermal activity is the best marker for distinguishing between low and high pain levels. However, recursive feature elimination showed that an optimal subset of features for all modalities includes characteristics retrieved from several modalities. Moreover, the study's findings indicate that differences in physiological responses to pain in HS and CBPP remain small.

Interoceptive rhythms in the brain

Sensing internal bodily signals, or interoception, is fundamental to maintain life. However, interoception should not be viewed as an isolated domain, as it interacts with exteroception, cognition and action to ensure the integrity of the organism. Focusing on cardiac, respiratory and gastric rhythms, we review evidence that interoception is anatomically and functionally intertwined with the processing of signals from the external environment. Interactions arise at all stages, from the peripheral transduction of interoceptive signals to sensory processing and cortical integration, in a network that extends beyond core interoceptive regions. Interoceptive rhythms contribute to functions ranging from perceptual detection up to sense of self, or conversely compete with external inputs. Renewed interest in interoception revives long-standing issues on how the brain integrates and coordinates information in distributed regions, by means of oscillatory synchrony, predictive coding or multisensory integration. Considering interoception and exteroception in the same framework paves the way for biological modes of information processing specific to living organisms.

Efficacy of manual therapy and pelvic floor exercises for pain reduction in primary dysmenorrhea: A prospective observational study

BACKGROUND

Primary dysmenorrhea represents one of the most common causes of pelvic and low back pain. Pharmacological treatment can present some side effects, and non-pharmacological treatments should be considered to improve the symptoms of primary dysmenorrhea. The aim of this study was to evaluate the efficacy of manual therapy (MT), pelvic floor exercises (PFE), and their combination (MT + PFE) to improve clinical outcomes and pain sensitivity in women with primary dysmenorrhea.

METHODS

A prospective observational study was conducted. Thirty females (age 25.0 ± 6.1 y) with history of primary dysmenorrhea participated to 8 sessions of 60 min of either MT, PFE or MT + PFE, twice per week. They participated to the different treatments according to the different services offered by the school of physiotherapy. A 0-10 numeric rating scale (NRS) was administered to assess subjective pain, while short-form 36 (SF-36) was used to evaluate quality of life. The pressure pain threshold (PPT) was assessed with a portable algometer on different pelvic and lumbar areas.

RESULTS

Independently from the treatment, significant improvements were reported for general pain NRS (p < 0.001; pη2 = 0.511), as well as most the domains of the SF-36, although the general health domain did not reach statistical significance (p = 0.613; pη2 = 0.010). PPT revealed a general improvement in all tested body areas, although on the quadratus lumborum, the PFE treatment did not induce a significant improvement compared to the MT and MT + PFE protocols (p = 0.039).

CONCLUSIONS

These findings highlight the importance of proposing physiotherapy treatments to females with primary dysmenorrhea to improve symptoms, with manual therapy combined with active pelvic floor exercise providing the best outcomes including an improvement of lumbar pain thresholds.

Expiratory-gated Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) does not Further Augment Heart Rate Variability During Slow Breathing at 0.1 Hz

As cardiac vagal control is a hallmark of good health and self-regulatory capacity, researchers are seeking ways to increase vagally mediated heart rate variability (vmHRV) in an accessible and non-invasive way. Findings with transcutaneous auricular vagus nerve stimulation (taVNS) have been disappointing in this respect, as its effects on vmHRV are inconsistent at best. It has been speculated that combining taVNS with other established ways to increase vmHRV may produce synergistic effects. To test this idea, the present study combined taVNS with slow breathing in a cross-over design. A total of 22 participants took part in two sessions of breathing at 6 breaths/min: once combined with taVNS, and once combined with sham stimulation. Electrical stimulation (100 Hz, 400 µs) was applied during expiration, either to the tragus and cavum conchae (taVNS) or to the earlobe (sham). ECG was recorded during baseline, 20-minutes of stimulation, and the recovery period. Frequentist and Bayesian analyses showed no effect of taVNS (in comparison to sham stimulation) on the root mean square of successive differences between normal heartbeats, mean inter-beat interval, or spectral power of heart rate variability at a breathing frequency of 0.1 Hz. These findings suggest that expiratory-gated taVNS combined with the stimulation parameters examined here does not produce acute effects on vmHRV during slow breathing.

Acute dyspnea in the emergency department: a clinical review

Acute dyspnea represents one of the most frequent symptoms leading to emergency room evaluation. Its significant prognostic value warrants a careful evaluation. The differential diagnosis of dyspnea is complex due to the lack of specificity and the loose association between its intensity and the severity of the underlying pathological condition. The initial assessment of dyspnea calls for prompt diagnostic evaluation and identification of optimal monitoring strategy and provides information useful to allocate the patient to the most appropriate setting of care. In recent years, accumulating evidence indicated that lung ultrasound, along with echocardiography, represents the first rapid and non-invasive line of assessment that accurately differentiates heart, lung or extra-pulmonary involvement in patients with dyspnea. Moreover, non-invasive respiratory support modalities such as high-flow nasal oxygen and continuous positive airway pressure have aroused major clinical interest, in light of their efficacy and practicality to treat patients with dyspnea requiring ventilatory support, without using invasive mechanical ventilation. This clinical review is focused on the pathophysiology of acute dyspnea, on its clinical presentation and evaluation, including ultrasound-based diagnostic workup, and on available non-invasive modalities of respiratory support that may be required in patients with acute dyspnea secondary or associated with respiratory failure.

Frequency and risk factors for failed weaning from supplemental oxygen therapy after general anesthesia at a postanesthesia care unit: a retrospective cohort study

BACKGROUND

Patients are administered supplemental oxygen upon emergence from general anesthesia against the risk of hypoxia. However, few studies have assessed the weaning from supplemental oxygen therapy. This study investigated the frequency and risk factors of failure to discontinue supplemental oxygen at a postanesthesia care unit (PACU).

METHODS

This retrospective cohort study was conducted in a tertiary hospital. We reviewed the medical records of adult patients admitted to the PACU after general anesthesia for elective surgery between January 2022 and November 2022. The primary endpoint was the frequency of failed weaning from supplemental oxygen therapy at PACU. A failed weaning was defined as oxygen saturation (SpO2) < 92% after discontinuing oxygen administration. The rate of failed discontinuation of supplemental oxygen at the PACU was assessed. Demographics, intraoperative, and postoperative factors were explored to determine potential associations with failed weaning from supplemental oxygen therapy using logistic regression analysis.

RESULTS

We analyzed 12,109 patients. We identified 842 cases of failed weaning from supplemental oxygen therapy, with a frequency of 1:14 (95% confidence interval [CI], 1:15-1:13). Risk factors that showed the strongest associations with failed weaning included postoperative hypothermia (odds ratio [OR], 5.42; 95% CI, 4.40-6.68; P < 0.001), major abdominal surgery (OR, 4.04; 95% CI, 3.29-4.99; P < 0.001), and preoperative SpO2 < 92% in room air (OR, 3.15; 95% CI, 2.09-4.64; P < 0.001).

CONCLUSION

In the analysis of more than 12,000 general anesthetics, an overall risk of failed weaning from supplemental oxygen therapy of 1:14 was observed. The identified risk factors may help determine the discontinuation of supplemental oxygen administration at PACU.

TRIAL REGISTRATION

Not applicable.

Hierarchical Classification Strategy for Mitigating the Impact of The Presence of Pain in fNIRS-based BCIs

Brain computer interfaces (BCIs) can find applications in assistive systems for patients who experience conditions that impede their motor abilities. A BCI uses signals acquired from the brain to control external devices. As physical pain influences cortical signals, the presence of pain can negatively impact the performance of the BCI. In this work, we propose a strategy to mitigate this negative impact. Cortical signals are acquired from test subjects while they performed two mental arithmetic tasks, in the presence and the absence of painful stimuli. The task of the BCI is to reliably classify the two mental arithmetic tasks from the cortical recordings, irrespective of the presence or the absence of pain. We propose to do this classification, hierarchically, in two levels. In the first level, the data is classified into those captured in the presence and the absence of pain. Depending on the results of the classification from the first level, in the second level, the BCI performs the classification of tasks using a classifier trained either in the presence or the absence of pain. A 1-dimensional convolutional neural network (1D-CNN) is used for classification at both levels. It is observed that using this hierarchical strategy, the BCI is able to classify the tasks with an accuracy greater than 90%, irrespective of the presence or the absence of pain. Given that the presence of physical pain has shown previously to reduce the classification accuracy of a BCI to almost chance levels, this mitigation strategy will be a significant step towards enhancing the performance of BCIs when they are used in assistive systems for patients.

Sports Performance and Breathing Rate: What Is the Connection? A Narrative Review on Breathing Strategies

Breathing is a natural and necessary process for humans. At the same time, the respiratory pace and frequency can vary so much, depending on the status of the subject. Specifically, in sports, breathing can have the effect of limiting performance from a physiological point of view, or, on the other hand, breathing can regulate the psychological status of the athletes. Therefore, the aim of this narrative review is to focus on the literature about the physiological and psychological aspects of breathing pace in sports performance, merging these two aspects because they are usually considered split, in order to create a new integrated vision of breathing and sports performance. Voluntary breathing can be divided into a slow or fast pace (VSB and VFB, respectively), and their effects on both the physiological and psychological parameters are very different. VSB can benefit athletes in a variety of ways, not just physically but mentally as well. It can help improve cardiovascular fitness, reduce stress and anxiety, and improve overall health and well-being, allowing athletes to maintain focus and concentration during training and competition. VFB is normal during physical training and competition, but away from training, if it is not voluntary, it can cause feelings of anxiety, panic, dizziness, and lightheadedness and trigger a stress response in the body, affecting the athlete's quality of life. In summary, the role of breathing in the performance of athletes should be considered, although no definitive data are available. The connection between breathing and sports performance is still unclear, but athletes can obtain benefits in focus and concentration using slow breathing strategies.

Protocol of identical exercise programs with and without specific breathing techniques for the treatment of chronic non-specific low back pain: randomized feasibility trial with two-month follow-up

BACKGROUND

Chronic low back pain (CLBP) is a leading cause of disability globally. Exercise therapies are one of the commonly prescribed treatment options for CLBP. The specific exercise therapies for CLBP most commonly target movement dysfunction, but seldom brain-based pain modulation. Exercise therapies with specific breathing techniques (SBTs) have been shown to influence and enhance brain-based structural and functional pain modulation.

AIMS AND OBJECTIVES

To assess the feasibility of the SBTs protocol, eligibility criteria, randomization, and dropout rates. To quantify the changes in patient outcome measures and choose the most relevant measure for larger-scale study. To quantify self-adherence levels to home exercise and monitor and record possible pain medication and other treatment modality usage, and adverse events during exercise.

DESIGN

A parallel randomised analyst-blinded feasibility trial with two-month follow-up.

OUTCOME MEASURES

Feasibility related to aims and objectives. Multiple pain- and health-related patient-reported outcome measures of pain intensity, disability, central sensitization, anxiety, kinesiophobia, catastrophising, self-efficacy, sleep quality, quality of life, and health and well-being status. Exercise adherence, pain medication and other treatment modality usage, and possible adverse events related to exercises will be monitored and recorded.

METHODS

Thirty participants will be randomized to movement control exercise with SBTs (15 subjects in experimental group) or movement control exercise without SBTs (15 subjects in control group) in private chiropractic practice setting with two-month follow-up. Trial registration number; NCT05268822.

DISCUSSION

The clinical difference in effectiveness between practically identical exercise programs in uniform study settings with or without SBTs has not been studied before. This study aims to inform feasibility and help determine whether progression to a full-scale trial is worthwhile.

Multiple sensor theory in airway mechanosensory units

Two conventional doctrines govern airway mechanosensory interpretation: One-Sensor Theory (OST) and Line-Labeled Theory (LLT). In OST, one afferent fiber connects to a single sensor. In LLT, a different type of sensor sends signals via its specific line to a particular brain region to evoke its reflex. Thus, airway slowly adapting receptors (SARs) inhibit breathing and rapidly adapting receptors (RARs) stimulate breathing. However, recent studies show many different mechanosensors connect to a single afferent fiber (Multiple-Sensor Theory, MST). That is, SARs and RARs may send different types of information through the same afferent pathway, indicating different information has been integrated at the sensory unit level. Thus, a sensory unit is not merely a transducer (textbook concept), but also a processor. MST is a conceptual shift. Data generated over last eight decades under OST require re-interpretation.

A systematic review of neurophysiological sensing for the assessment of acute pain

Pain is a complex and personal experience that presents diverse measurement challenges. Different sensing technologies can be used as a surrogate measure of pain to overcome these challenges. The objective of this review is to summarise and synthesise the published literature to: (a) identify relevant non-invasive physiological sensing technologies that can be used for the assessment of human pain, (b) describe the analytical tools used in artificial intelligence (AI) to decode pain data collected from sensing technologies, and (c) describe the main implications in the application of these technologies. A literature search was conducted in July 2022 to query PubMed, Web of Sciences, and Scopus. Papers published between January 2013 and July 2022 are considered. Forty-eight studies are included in this literature review. Two main sensing technologies (neurological and physiological) are identified in the literature. The sensing technologies and their modality (unimodal or multimodal) are presented. The literature provided numerous examples of how different analytical tools in AI have been applied to decode pain. This review identifies different non-invasive sensing technologies, their analytical tools, and the implications for their use. There are significant opportunities to leverage multimodal sensing and deep learning to improve accuracy of pain monitoring systems. This review also identifies the need for analyses and datasets that explore the inclusion of neural and physiological information together. Finally, challenges and opportunities for designing better systems for pain assessment are also presented.

Non-Invasive Objective Markers to Measure Pain: A Direction to Develop a Pain Device - A Narrative Review

Objective

To review the literature regarding non-invasive objective measurements of pain. Measuring pain is of uttermost importance, but it can be an inconvenient task, especially in terms of the interpretation of patient's information. Reiterating, there is no "standard" that provides the physician with a method to objectively quantify this problem of patient's pain. For assessing the pain, physician relies solely on unidimensional assessment tools or questionnaire-based pain assessment. Although pain is a subjective experience of the patient, but there is a need to measure pain sometimes in the individuals who cannot communicate their quality and severity of pain.

Material and Methods

The articles from PubMed and Google Scholar without any year and age limit were searched in the current narrative review. A total of 16 markers were searched and their relation to pain was studied.

Results

Studies have shown that these markers change in relation to pain and it can be considered a valuable tool for pain measurement but there are multiple factors like psychological and emotional factors which affect these markers.

Conclusion

There is lack of evidence to show which marker can be used for measuring pain accurately. This narrative review is an attempt to look into the various pain-related markers that can be used and it calls for further studies including clinical trials with different diseases and taking into accounts different factors affecting pain to give an accurate measurement of pain.

Live and Recorded Music Interventions to Reduce Postoperative Pain: Protocol for a Nonrandomized Controlled Trial

BACKGROUND

Postoperative patients who were previously engaged in the live musical intervention Meaningful Music in Healthcare reported significantly reduced perception of pain than patients without the intervention. This encouraging finding indicates a potential for postsurgical musical interventions to have a place in standard care as therapeutic pain relief. However, live music is logistically complex in hospital settings, and previous studies have reported the more cost-effective recorded music to serve as a similar pain-reducing function in postsurgical patients. Moreover, little is known about the potential underlying physiological mechanisms that may be responsible for the reduced pain perceived by patients after the live music intervention.

OBJECTIVE

The primary objective is to see whether a live music intervention can significantly lower perceived postoperative pain compared to a recorded music intervention and do-nothing control. The secondary objective is to explore the neuroinflammatory underpinnings of postoperative pain and the potential role of a music intervention in mitigating neuroinflammation.

METHODS

This intervention study will compare subjective postsurgical pain ratings among 3 groups: live music intervention, recorded music intervention, and standard care control. The design will take the form of an on-off nonrandomized controlled trial. Adult patients undergoing elective surgery will be invited to participate. The intervention is a daily music session of up to 30 minutes for a maximum of 5 days. The live music intervention group is visited by professional musicians once a day for 15 minutes and will be asked to interact. The recorded music active control intervention group receives 15 minutes of preselected music over headphones. The do-nothing group receives typical postsurgical care that does not include music.

RESULTS

At study completion, we will have an empirical indication of whether live music or recorded music has a significant impact on postoperative perceived pain. We hypothesize that the live music intervention will have more impact than recorded music but that both will reduce the perceived pain more than care-as-usual. We will moreover have the preliminary evidence of the physiological underpinnings responsible for reducing the perceived pain during a music intervention, from which hypotheses for future research may be derived.

CONCLUSIONS

Live music can provide relief from pain experienced by patients recovering from surgery; however, it is not known to what degree live music improves the patients' pain experience than the logistically simpler alternative of recorded music. Upon completion, this study will be able to statistically compare live versus recorded music. This study will moreover be able to provide insight into the neurophysiological mechanisms involved in reduced pain perception as a result of postoperative music listening.

TRIAL REGISTRATION

The Netherlands Central Commission on Human Research NL76900.042.21; https://www.toetsingonline.nl/to/ccmo_search.nsf/fABRpop?readform&unids=F2CA4A88E6040A45C1258791001AEA44.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/40034.

Combined effect of transcutaneous auricular vagus nerve stimulation and 0.1 Hz slow-paced breathing on working memory

Background

Previous research has found that transcutaneous auricular vagus nerve stimulation (taVNS) can improve working memory (WM) performance. It has also been shown that 0.1 Hz slow-paced breathing (SPB, i.e., breathing at a rate of approximately 6 breaths/min) can significantly influence physical state and cognitive function via changes in autonomic afferent activity. In the present study, we investigated the synergistic effects of taVNS and SPB on WM performance.

Methods

A total of 96 healthy people participated in this within-subjects experiment involving four conditions, namely taVNS, SPB, combined taVNS with SPB (taVNS + SPB), and sham. Each participant underwent each intervention for 30 min and WM was compared pre- and post-intervention using the spatial and digit n-back tasks in a random order four times. Permutation-based analysis of variance was used to assess the interaction between time and intervention.

Results

For the spatial 3-back task, a significant interaction between time and intervention was found for the accuracy rate of matching trials (mACC, p = 0.03). Post hoc analysis suggested that both taVNS and taVNS + SPB improved WM performance, however, no significant difference was found in the SPB or sham groups.

Conclusion

This study has replicated the effects of taVNS on WM performance reported in previous studies. However, the synergistic effects of combined taVNS and SPB warrant further research.

The Validity of Vital Signs for Pain Assessment in critically Ill Adults: A Narrative Review

OBJECTIVES

Pain assessment in the intensive care unit (ICU) is challenging because many patients are unable to self-report or exhibit pain-related behaviors. In such situations, vital signs (VS) through continuous monitoring are alternative cues for pain assessment. This review aimed to describe the reliability and validity of VS for ICU pain assessment.

DESIGN

Narrative review of the literature.

DATA SOURCES

Medline, Embase, CINAHL, Cochrane.

REVIEW/ANALYSIS METHODS

A narrative review was conducted with a comprehensive search in four databases. Search terms included VS, pain assessment, and ICU.

RESULTS

Out of 1,359 results, 30 studies from 17 countries were included. Heart rate, blood pressure, and respiratory rate were most used for ICU pain assessment. Assessments were performed at rest before procedures, during nociceptive and non-nociceptive procedures, and after procedures. Increases in respiratory rate were clinically significant by more than 25% during nociceptive procedures (e.g., endotracheal suctioning, turning) compared with rest/pre-procedures in five studies. Correlations of VS with self-reported pain (reference standard measure) and behavioral pain scores (alternative measure) were absent or weak.

CONCLUSIONS

VS are not valid indicators for ICU pain assessment. Increases of respiratory rate may be a cue for the detection of pain. However, fluctuations in respiratory rate can be influenced by opioids or controlled ventilation mode. Our results dissuade the use of VS for pain assessment because of the lack of association with ICU pain reference standards. Other physiologic measures of pain in critically ill adults should be explored.

Measuring pain and nociception: Through the glasses of a computational scientist. Transdisciplinary overview of methods

In a healthy state, pain plays an important role in natural biofeedback loops and helps to detect and prevent potentially harmful stimuli and situations. However, pain can become chronic and as such a pathological condition, losing its informative and adaptive function. Efficient pain treatment remains a largely unmet clinical need. One promising route to improve the characterization of pain, and with that the potential for more effective pain therapies, is the integration of different data modalities through cutting edge computational methods. Using these methods, multiscale, complex, and network models of pain signaling can be created and utilized for the benefit of patients. Such models require collaborative work of experts from different research domains such as medicine, biology, physiology, psychology as well as mathematics and data science. Efficient work of collaborative teams requires developing of a common language and common level of understanding as a prerequisite. One of ways to meet this need is to provide easy to comprehend overviews of certain topics within the pain research domain. Here, we propose such an overview on the topic of pain assessment in humans for computational researchers. Quantifications related to pain are necessary for building computational models. However, as defined by the International Association of the Study of Pain (IASP), pain is a sensory and emotional experience and thus, it cannot be measured and quantified objectively. This results in a need for clear distinctions between nociception, pain and correlates of pain. Therefore, here we review methods to assess pain as a percept and nociception as a biological basis for this percept in humans, with the goal of creating a roadmap of modelling options.

Deep breathing alleviates propofol-induced pain: a prospective, randomized, single-blind study

PURPOSE

Propofol is commonly used to induce general anesthesia; however, the pain caused during propofol injection is a disadvantage. This study aimed to assess whether deep breathing attenuates propofol injection pain.

METHODS

This prospective, single-blind, randomized controlled study included 200 patients who were scheduled to undergo elective surgery under general anesthesia and randomly and equally divided them into group D and group C. The observers were not blinded to the pain-relieving modality, but each patient was blinded. Group D patients were requested to repeatedly take deep breaths throughout general anesthesia induction with propofol. Group C patients were requested to breathe in the usual manner. The intensity of propofol injection pain was evaluated using the visual analog scale (VAS). Furthermore, we recorded the patients' pain expressions, including grimace or hand-withdrawal, and the recalled pain measured using a VAS in the post-anesthetic care units (PACU).

RESULTS

Compared with patients in group C, those in group D showed significantly reduced VAS scores for propofol injection pain (20 [interquartile range (IQR): 0-48] vs. 37 [IQR 9-65], P = 0.017) and recalled pain in the PACU (16 [IQR 0-32] vs. 26 [IQR 0.5-51], P = 0.031). Further, the grimace incidence was significantly lower in group D (18%) than in group C (45%) (P < 0.001). There was no significant difference in the incidence of pain at induction, recalled pain, or hand-withdrawal.

CONCLUSIONS

Deep breathing could be an easy, safe, and inexpensive method for reducing pain during propofol injection.

Conscious connected breathing with breath retention intervention in adults with chronic low back pain: protocol for a randomized controlled pilot study

BACKGROUND

Chronic pain is a major source of human suffering, and chronic low back pain (cLBP) is among the most prevalent, costly, and disabling of pain conditions. Due to the significant personal and societal burden and the complex and recurring nature of cLBP, self-management approaches that can be practiced at home are highly relevant to develop and test. The respiratory system is one of the most integrated systems of the body, and breathing is bidirectionally related with stress, emotion, and pain. Thus, the widespread physiological and psychological impact of breathing practices and breathwork interventions hold substantial promise as possible self-management strategies for chronic pain. The primary aim of the current randomized pilot study is to test the feasibility and acceptability of a conscious connected breathing with breath retention intervention compared to a sham control condition.

METHODS

The rationale and procedures for testing a 5-day conscious connected breathing with breath retention intervention, compared to a deep breathing sham control intervention, in 24 adults (18-65 years) with cLBP is described. Both interventions will be delivered using standardized audio recordings and practiced over 5 days (two times in-person and three times at-home), and both are described as Breathing and Attention Training to reduce possible expectancy and placebo effects common in pain research. The primary outcomes for this study are feasibility and acceptability. Feasibility will be evaluated by determining rates of participant recruitment, adherence, retention, and study assessment completion, and acceptability will be evaluated by assessing participants' satisfaction and helpfulness of the intervention. We will also measure other clinical pain, psychological, behavioral, and physiological variables that are planned to be included in a follow-up randomized controlled trial.

DISCUSSION

This will be the first study to examine the effects of a conscious connected breathing with breath retention intervention for individuals with chronic pain. The successful completion of this smaller-scale pilot study will provide data regarding the feasibility and acceptability to conduct a subsequent trial testing the efficacy of this breathing self-management practice for adults with cLBP.

TRIAL REGISTRATION

Clinicaltrials.gov, identifier NCT04740710 . Registered on 5 February 2021.

Hypocapnia attenuates local skin thermal perception to innocuous warm and cool stimuli in normothermic resting humans

When one is exposed to a stressful situation in their daily life, a common response is hyperventilation. Although the physiological significance of stress-induced hyperventilation remains uncertain, this response may blunt perception of the stress-inducing stimulus. This study examined the effects of voluntary hyperventilation and resultant hypocapnia on the local skin thermal detection threshold in normothermic resting humans. Local skin thermal detection thresholds were measured in 15 young adults (three females) under three breathing conditions: 1) spontaneous breathing (Control trial), 2) voluntary hypocapnic hyperventilation (HH trial), and 3) voluntary normocapnic hyperventilation (NH trial). Local skin thermal detection thresholds were measured using thermostimulators containing a Peltier element that were attached to the forearm and forehead. The temperature of the probe was initially equilibrated to the skin temperature, then gradually increased or decreased at a constant rate (±0.1 °C/s) until the participants felt warmth or coolness. The difference between the initial skin temperature and the local skin temperature at which the participant noticed warmth/coolness was assessed as an index of the local skin warm/cool detection threshold. Local detection of warm and cool stimuli did not differ between the Control and NH trials, but it was blunted in the HH trial as compared with the Control and NH trials, except for detection of warm stimuli on the forearm. These findings suggest that hyperventilation-induced hypocapnia, not hyperventilation per se, attenuates local skin thermal perception, though changes in responses to warm stimuli may not be clearly perceived at some skin areas (e.g., forearm).

Effects of extremity trauma on physiological responses to hemorrhage in conscious rats

Although physiological responses to hemorrhage are well-studied, hemorrhage is often accompanied by trauma, and it remains unclear how injury affects these responses. This study examined effects of extremity trauma on cardiorespiratory responses and survival to moderate (37%; H-37) or severe (50%; H-50) hemorrhage in rats. Transmitter and carotid catheter implantation and extremity trauma (fibular fracture and muscle injury) were conducted 2 wk, 24 h, and 90 min, respectively, before conscious hemorrhage. Mean arterial pressure (MAP) and heart rate (HR; via telemetry), and respiration rate (RR), minute volume (MV), and tidal volume (TV; via plethysmography) were measured throughout the 25 min hemorrhage and remainder of the 4 h observation period. There were four groups: 1) H-37, no trauma (NT; n = 17); 2) H-37, extremity trauma (T, n = 18); 3) H-50, NT (n = 20); and 4) H-50, T (n = 20). For H-37, during and after hemorrhage, T increased HR (P ≤ 0.031) and MV (P ≤ 0.048) compared with NT rats. During H-50, T increased HR (0.041) and MV (P = 0.043). After hemorrhage, T increased MV (P = 0.008) but decreased HR (P = 0.007) and MAP (P = 0.039). All cardiorespiratory differences between T and NT groups were intermittent. Importantly, both survival time (159.8 ± 78.2 min vs. 211.9 ± 60.3 min; P = 0.022; mean ± SD) and percent survival (45% vs. 80%; P = 0.048) were less in T versus NT rats after H-50. Trauma interacts with physiological systems in a complex manner and no single cardiorespiratory measure was sufficiently altered to indicate that it alone could account for increased mortality after H-50.NEW & NOTEWORTHY In both civilian and military settings, severe hemorrhage rarely occurs in the absence of tissue trauma, yet many animal models for the study of hemorrhage do not include significant tissue trauma. This study using conscious unrestrained rats clearly demonstrates that extremity trauma worsens the probability of survival after a severe hemorrhage. Although no single cardiorespiratory factor accounted for the increased mortality, multiple modest time-related cardiorespiratory responses to the trauma were observed suggesting that their combined dysfunction may have contributed to the reduced survival.

Breathing Exercises for Pain Management in Cancer Survivors: A Systematic Review

OBJECTIVES

Unmanaged pain significantly affects cancer survivors' quality of life. Nurses should play a significant role in pain management through non-pharmacological interventions. This review aims to explore the efficacy and safety of breathing exercises for pain management in all cancer survivors.

DESIGN

A systematic review.

DATA SOURCES

Thirteen databases, including PubMed, EMBase, CENTRAL, MEDLINE, CINAHL, JBI, Science Direct, Scopus, SocINDEX, Web of Science, PsycINFO, CNKI, and Wan Fang, were searched from inception to May, 2021.

REVIEW/ANALYSIS METHODS

Studies that focused on the efficacy of breathing exercises for pain management, regardless of the age of the cancer survivors, were included. Cochrane tools were used for the quality appraisal of the included studies. Because of the limited number of studies, descriptive data analysis was used to summarize the results.

RESULTS

Ten studies were included. Slow pursed lip breathing showed benefits for post-surgical pain. Contradictory findings were identified in the Enhanced Recovery After Surgery for post-surgical pain. Slow deep breathing and Hey-Hu regular breathing techniques were effective for pain management in pediatric cancer patients. The Active Cycle of Breathing Technique and five-minute mindful breathing did not have any statistically significant effects on pain relief. Quality of life was measured in three studies, with some improvement. Only one study addressed adverse events and reported that no adverse events occurred.

CONCLUSIONS

Breathing exercises may be a promising approach to pain relief in cancer survivors. However, more rigorously designed studies are required to establish the evidence.

Can Exercise Affect the Pain Characteristics in Patients with Fibromyalgia? A Randomized Controlled Trial

Exercise is often recommended for fibromyalgia. The aim of this study was to investigate the possible influence and change in the pain characteristics of fibromyalgia patients when breathing exercises were added to their exercise program. A total of 106 patients were included and randomly divided into two groups. Τhe first group of patients followed a program of active exercises up to the limits of pain, lasting 30 min with a repetition of two times a week. Patients of the second group followed the same program with the addition of diaphragmatic breaths when they reached the pain limit. The patients completed three questionnaires: the Fibromyalgia Rapid Screening Tool (FiRST), the Brief Pain Inventory (BPI), and the Pain Quality Assessment Scale (PQAS)-once at the beginning, once again after three weeks of exercise, and again 3 months since the beginning of the program. Independent t-tests for the mean total change scores in pain scales demonstrated that for the second group there was a greater improvement in all pain scales, except for the PQAS Deep Pain subscale (p = 0.38). In conclusion, both groups showed significant improvement in all characteristics of the pain scales; however, the improvement of the second group was significantly higher.

Automatic detection of pain using machine learning

Pain is one of the most common symptoms reported by individuals presenting to hospitals and clinics and is associated with significant disability and economic impacts; however, the ability to quantify and monitor pain is modest and typically accomplished through subjective self-report. Since pain is associated with stereotypical physiological alterations, there is potential for non-invasive, objective pain measurements through biosensors coupled with machine learning algorithms. In the current study, a physiological dataset associated with acute pain induction in healthy adults was leveraged to develop an algorithm capable of detecting pain in real-time and in natural field environments. Forty-one human subjects were exposed to acute pain through the cold pressor test while being monitored using electrocardiography. A series of respiratory and heart rate variability features in the time, frequency, and nonlinear domains were calculated and used to develop logistic regression classifiers of pain for two scenarios: (1) laboratory/clinical use with an F1 score of 81.9% and (2) field/ambulatory use with an F1 score of 79.4%. The resulting pain algorithms could be leveraged to quantify acute pain using data from a range of sources, such as ECG data in clinical settings or pulse plethysmography data in a growing number of consumer wearables. Given the high prevalence of pain worldwide and the lack of objective methods to quantify it, this approach has the potential to identify and better mitigate individual pain.

Pain is reduced by transcutaneous cervical vagus nerve stimulation and correlated with cardiorespiratory variability measures in the context of opioid withdrawal

Over 100,000 individuals in the United States lost their lives secondary to drug overdose in 2021, with opioid use disorder (OUD) being a leading cause. Pain is an important component of opioid withdrawal, which can complicate recovery from OUD. This study's objectives were to assess the effects of transcutaneous cervical vagus nerve stimulation (tcVNS), a technique shown to reduce sympathetic arousal in other populations, on pain during acute opioid withdrawal and to study pain's relationships with objective cardiorespiratory markers. Twenty patients with OUD underwent opioid withdrawal while participating in a two-hour protocol. The protocol involved opioid cues to induce opioid craving and neutral conditions for control purposes. Adhering to a double-blind design, patients were randomly assigned to receive active tcVNS (n = 9) or sham stimulation (n = 11) throughout the protocol. At the beginning and end of the protocol, patients' pain levels were assessed using the numerical rating scale (0-10 scale) for pain (NRS Pain). During the protocol, electrocardiogram and respiratory effort signals were measured, from which heart rate variability (HRV) and respiration pattern variability (RPV) were extracted. Pre- to post- changes (denoted with a Δ) were computed for all measures. Δ NRS Pain scores were lower (P = 0.045) for the active group (mean ± standard deviation: -0.8 ± 2.4) compared to the sham group (0.9 ± 1.0). A positive correlation existed between Δ NRS pain scores and Δ RPV (Spearman's ρ = 0.46; P = 0.04). Following adjustment for device group, a negative correlation existed between Δ HRV and Δ NRS Pain (Spearman's ρ = -0.43; P = 0.04). This randomized, double-blind, sham-controlled pilot study provides the first evidence of tcVNS-induced reductions in pain in patients with OUD experiencing opioid withdrawal. This study also provides the first quantitative evidence of an association between breathing irregularity and pain. The correlations between changes in pain and changes in objective physiological markers add validity to the data. Given the clinical importance of reducing pain non-pharmacologically, the findings support the need for further investigation of tcVNS and wearable cardiorespiratory sensing for pain monitoring and management in patients with OUD.

Slow, deep breathing intervention improved symptoms and altered rectal sensitivity in patients with constipation-predominant irritable bowel syndrome

BACKGROUND AND AIM

Limited treatment options have been shown to alter the natural course of irritable bowel syndrome (IBS). Slow, deep breathing (SDB) is a common pain self-management intervention. This pilot study aimed to explore the impact of SDB on measures of autonomic and anorectal functions as well as patient-reported symptoms in constipation-predominant IBS (IBS-C).

METHODS

Eighty-five IBS-C patients were enrolled in this study and randomly assigned to the experimental group (Group A, n = 42) and the control group (Group B, n = 43). SDB was conducted at six breathing cycles per minute with an inhalation for 4 s and exhalation for 6 s at a ratio of 2:3 and repeated for 30 min during the intervention. All subjects underwent high-resolution anorectal manometry (HRAM) and completed the standardized IBS symptom severity system (IBS-SSS) questionnaire. Meanwhile, changes in stool consistency, weekly frequency of complete spontaneous bowel movements (CSBMs), and weekly frequency of spontaneous bowel movements (SBMs) were recorded. All IBS-C patients received electrocardiogram (ECG) recordings for heart rate variability (HRV) analysis at baseline, weeks 3, 6.

RESULTS

At baseline, no differences were found between Groups A and B. The IBS-SSS score and its five sub-scores of Group B patients were significantly higher at week 6 than those of Group A patients (all p < 0.001). Furthermore, compared with Group B patients, Group A patients had a significantly higher threshold volume for the first sensation (p < 0.001), desire to defecate (p = 0.017), and maximum tolerable volume (p = 0.018) at week 6 of the SDB treatment. We also noted significant improvements in stool consistency (p = 0.002), weekly SBM frequencies (p < 0.001), and weekly CSBM frequencies (p = 0.018) of Group A patients at week 6 when compared with Group B patients. Finally, the corrected high frequency (HF) of Group A patients was significantly higher than the HF of Group B patients at week 3 (p < 0.001) and at week 6 (p < 0.001). Likewise, patients in Group A had a significantly higher root mean square of the successive differences (RMSSD) than that of patients in Group B at week 3 (p < 0.001) and at week 6 (p < 0.001).

CONCLUSION

We found that a 6-week SDB intervention improved symptoms and altered rectal sensation in IBS-C patients. Moreover, SDB enhanced vagal activity. These findings suggest that the effect of SDB on IBS-C may be due to mechanisms involving autonomic responses.

The effect of ketamine on delta-range coupling between prefrontal cortex and hippocampus supported by respiratory rhythmic input from the olfactory bulb

Respiratory rhythm plays an important role in cognitive functions in rodents, as well as in humans. Respiratory related oscillation (RRO), generated in the olfactory bulb (OB), is an extrinsic rhythm imposed on brain networks. In rats, RRO can couple with intrinsic brain oscillations at theta frequency during sniffing and in the delta range outside of such episodes. Disruption of gamma synchronization in cortical networks by ketamine is well established whereas its effects on slow rhythms are poorly understood. We found in this study, that RRO in prefrontal cortex (PFC) and hippocampus (HC) remains present after ketamine injection, even on the background of highly unstable respiratory rate, co-incident with "psychotic-like" behavior and abnormal cortical gamma activity. Guided by the timing of ketamine-induced gamma reaction, pairwise coherences between structures exhibiting RRO and their correlation structure was statistically tested in 5-min segments post-injection (0-25 min) and during recovery (1, 5, 10 h). As in control, RRO in the OB was firmly followed by cortical-bound OB exits directed toward PFC but not to HC. RRO between these structures, however, significantly correlated with OB-HC but not with OB-PFC. The only exception to this general observation was observed during a short transitional period, immediately after injection. Ketamine has a remarkable history in psychiatric research. Modeling chronic NMDA-hypofunction using acute NMDA-receptor blockade shifted the primary focus of schizophrenia research to dysfunctional cortical microcircuitry and the recent discovery of ketamine's antidepressant actions extended investigations to neurophysiology of anxiety and depression. Cortical oscillations are relevant for understanding their pathomechanism.

Oxygen efficient respiratory Aid (OxEraTM) device: A safety study

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Africa is a continent that has many developing countries that have constant strain on their healthcare systems.

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Now with the COVID pandemic, the use of oxygen and need for cost efficient and safe oxygen devices has increased.

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OxEra^TM is an oxygen delivery device that has been designed and developed by a consortium named Umoya for emergency use (approval from SAPHRA) in the COVID 19 pandemic.

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Given the potential for the widespread utilisation of this oxygen device in a resource-limited setting, we performed a clinical assessment safety study.

Background

Severe Coronavirus Disease 2019 (COVID-19) can develop pneumonia with severe complications. The Oxygen Efficient Respiratory Aid (OxEra^TM) device has been granted SAPHRA approval for emergency COVID-19 pandemic use. The device has the potential to be used widely in the healthcare sector due to its efficient oxygen supply and adjustable wall positive expiratory pressure (PEP).

Objectives

We assessed whether the OxEra^TM device was safe to use in a healthy adult volunteer population. Our primary objective was to ensure there was no asphyxiation, as assessed by changes observed from baseline End Tidal Carbon Dioxide (ETCO₂) exceeding 6.3 mmHg and above the 45 mmHg threshold. We also monitored changes in vital organ signs and assessed the pain and comfort of the participant at various intervals with changes in PEPs.

Methods

This was an experimental safety study of the OxEra^TM Device on 30 healthy participants at the ICU training centre of Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa. Each participant had basic vital-signs, ETCO₂, and Oxygen saturation percentages (SpO₂%) taken at baseline until the end of 2 h. In the first 20 min, the PEP was increased by 5 cmH₂0 until 20 min, then continued for the rest of the time on a PEP of 5 cmH₂0. At each interval, vital signs, subjective comfort, pain, and visual scores were measured.

Results

Thirty healthy participants were enrolled. There was no significant difference in ETCO₂ from baseline until 2 h. No participant experienced an increase in measured ETCO₂ greater than 45 mmHg and no increase in ETCO₂ from baseline was greater than 6.3 mmHg. The median increase in ETCO₂ over the study period was 2 mmHg. There were no significant changes in respiratory rate and blood pressure. The heart rate decreased significantly (73–68 bpm). The VAS and comfort score had a significant increase over the 2 h from baseline of 0–2 at maximum; however, the PAS scores showed no significant increase.

Conclusion

Overall the OxEra^TM device achieved the safety endpoints set out. There was no sign of asphyxiation and there were appropriate physiological responses to changes in PEP once applied. The comfort of the mask did worsen over the 2 h; however, the scores were minimally worse on PEP application but improved once-off PEP. No adverse event was recorded at all.

Effect of Virtual Reality Hypnosis on Pain Threshold and Neurophysiological and Autonomic Biomarkers in Healthy Volunteers: Prospective Randomized Crossover Study

Background

Virtual reality hypnosis (VRH) is a promising tool to reduce pain. However, the benefits of VRH on pain perception and on the physiological expression of pain require further investigation.

Objective

In this study, we characterized the effects of VRH on the heat pain threshold among adult healthy volunteers while monitoring several physiological and autonomic functions.

Methods

Sixty healthy volunteers were prospectively included to receive nociceptive stimulations. The first set of thermal stimuli consisted of 20 stimulations at 60°C (duration 500 milliseconds) to trigger contact heat evoked potentials (CHEPs). The second set of thermal stimuli consisted of ramps (1°C/second) to determine the heat pain threshold of the participants. Electrocardiogram, skin conductance responses, respiration rate, as well as the analgesia nociception index were also recorded throughout the experiment.

Results

Data from 58 participants were analyzed. There was a small but significant increase in pain threshold in VRH (50.19°C, SD 1.98°C) compared to that in the control condition (mean 49.45°C, SD 1.87; P<.001, Wilcoxon matched-pairs signed-rank test; Cohen d=0.38). No significant effect of VRH on CHEPs and heart rate variability parameters was observed (all P>0.5; n=22 and n=52, respectively). During VRH, participants exhibited a clear reduction in their autonomic sympathetic tone, as shown by the lower number of nonspecific skin conductance peak responses (P<.001, two-way analysis of variance; n=39) and by an increase in the analgesia nociception index (P<.001, paired t-test; n=40).

Conclusions

The results obtained in this study support the idea that VRH administration is effective at increasing heat pain thresholds and impacts autonomic functions among healthy volunteers. As a nonpharmacological intervention, VRH has beneficial action on acute experimental heat pain. This beneficial action will need to be evaluated for the treatment of other types of pain, including chronic pain.