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1.
Int J Osteopath Med ; 42: 1-4, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34671414

RESUMO

Objective structured clinical examinations (OSCEs) are often used to assess the clinical competence of students in preprofessional osteopathy training. During the COVID-19 global pandemic, the final year OSCE in the RMIT University osteopathy program was redeveloped leveraging online technologies within COVID-19 guidelines such as hygiene and occupancy limitations. Final year osteopathy students were assessed using a hybrid ten station OSCE, comprising both online and face-to-face components. The examination was led by a pre-recorded narrated PowerPoint video. The video contained instructions, case information for five cases and prompts for the practical stations. A student model stepped into the room as needed for practical stations. The examiner assessed students from another room via video streaming, with limited interaction with students. The hybrid OSCE was conducted safely during Stage 4 restrictions adhering to COVID Safe guidelines, allowing robust competency assessment of final year students, enabling timely graduation and transition to practice. Institutional support, technology infrastructure, clear communication and stakeholder collaboration are key to successful implementation. The hybrid OSCE format offers a potential solution for institutions delivering high-stakes assessment in the continuing challenges of clinical assessment in the post COVID landscape. Adopting hybrid assessment formats may facilitate remote assessment of students in clinical placements.

2.
Chiropr Man Therap ; 28(1): 53, 2020 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-33076947

RESUMO

BACKGROUND: The hip abductor muscle group stabilises the pelvis during gait to prevent excessive pelvic drop. Hip abductor weakness has been linked to musculoskeletal conditions such as chronic low-back pain. As such, it is important that practitioners can correctly diagnose hip abductor weakness in a clinical setting. Although the Trendelenburg test is commonly used by practitioners, the validity of this test to assess hip abductor weakness in the absence of musculoskeletal injury remains questionable. The aim of this study was to determine the validity of the Trendelenburg test, as observed by a practitioner, to assess frontal plane pelvic motion and hip abductor strength in a population without intra-articular hip disorders. METHODS: This study was performed between June 14th and October 16th 2019. Eighteen participants were recruited for this study. Peak normalised isometric and isokinetic hip abductor torque were measured bilaterally (n = 36) using the Biodex System 4 isokinetic dynamometer. Each participant performed the Trendelenburg test bilaterally (n = 36) while a graduate year chiropractic practitioner assessed for a "positive" or "negative" sign. The test was simultaneously recorded using Vicon 3-Dimensional motion capture to measure frontal plane pelvic motion and elevation. Correlation analyses were performed between the measures of peak hip abductor torque and pelvic motion to determine if any relationship existed. Agreement between the practitioner and 3-Dimensional analysis was calculated using the kappa (κ) statistic. RESULTS: Weak, non-significant correlations were found between hip abductor strength and pelvic motion before outlier removal. Significant (p < 0.05) yet weak correlations were found after outlier removal, except for isometric hip abductor strength. Weak agreement was found between the chiropractic practitioner and 3-Dimesnional analysis for the Trendelenburg test assessment (κ = 0.22-0.25). CONCLUSIONS: This study found no significant relationship between normalised peak isometric and isokinetic hip abductor torque and frontal plane pelvic motion during the Trendelenburg test in a healthy young adult population. There was also poor agreement between the practitioner and pelvic motion assessments. Caution should be used when using this test, in the absence of intra-articular hip pathology, to assesses hip abductor weakness. Before any definitive conclusion can be made, studies with a larger sample size should be performed.


Assuntos
Teste de Esforço/instrumentação , Articulação do Quadril/fisiologia , Músculo Esquelético/fisiologia , Adulto , Antropometria , Teste de Esforço/métodos , Feminino , Articulação do Quadril/química , Humanos , Masculino , Força Muscular , Dinamômetro de Força Muscular , Pelve/fisiologia , Amplitude de Movimento Articular , Torque , Adulto Jovem
3.
BMC Musculoskelet Disord ; 21(1): 87, 2020 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-32035480

RESUMO

BACKGROUND: There is a paucity of literature regarding the conservative management of adult scoliosis. The authors review and summarize the literature from 1967 to 2018 on the clinical outcomes of spinal brace/orthosis use in this subgroup of the population. METHODS: CINAHL, Embase, CENTRAL, PubMed and PEDro were searched from database inception to the 30th of October, 2018. A combination of medical subject heading terms and keywords pertaining to three core concepts (adult, scoliosis, and braces/orthoses) were used in the search. Studies were included if A) clinical outcomes were collected from B) participants ≥18 years C) receiving spinal brace/orthosis treatment for D) primary degenerative (de novo) scoliosis or progressive idiopathic scoliosis. A step-wise screening process was employed which involved a title and abstract screen for relevancy followed by a full text eligibility appraisal by two authors. Data were extracted, and a risk of bias assessment was performed on the included cohort studies using the Newcastle-Ottawa Scale. Given the overall level and quality of the available evidence, conclusions were drawn based on a qualitative summary of the evidence. RESULTS: Ten studies (four case reports and six cohort studies) were included which detailed the clinical outcomes of soft (2 studies) or rigid bracing (8 studies), used as a standalone therapy or in combination with physiotherapy/rehabilitation, in 339 adults with various types of scoliosis. Most studies included female participants only. Commonly reported outcomes were pain (7 studies), function (3 studies) and Cobb angles (3 studies), with follow-up times ranging from 2 days to 17 years. Brace wear prescriptions ranged from 2 to 23 h per day, and there was mixed brace-compliance reported. Most studies reported modest or significant reduction in pain and improvement in function at follow-up. There were mixed findings with regards to Cobb angle changes in response to bracing. Participants from one study noted discomfort associated with bracing. Each of the six cohort studies demonstrated a high risk of bias. CONCLUSION: There is evidence to suggest that spinal brace/orthosis treatment may have a positive short - medium term influence on pain and function in adults with either progressive primary (de novo) degenerative scoliosis or progressive idiopathic scoliosis. At this point in time the evidence is of low quality and has been focused primarily on female patients with thoracolumbar and lumbar curves. More granular statements regarding the efficacy of different brace types or manufacturers, or the effect of this therapy on different curve types cannot be determined based on the current literature. Properly constructed prospective trials are required to better understand the efficacy of bracing in adult scoliosis.


Assuntos
Aparelhos Ortopédicos , Escoliose/terapia , Adulto , Humanos
4.
Chiropr Man Therap ; 27: 37, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31452871

RESUMO

Background: Chronic Obstructive Pulmonary Disease (COPD) is an increasingly prevalent respiratory disease that impacts on daily living. In addition to difficulty breathing, many people experience extrapulmonary comorbidities such as musculoskeletal disorders. Pulmonary rehabilitation can improve fitness and strength but may be difficult for patients with musculoskeletal disorders. Recent research indicates promising benefits of adding manual therapy to standard care to improve clinical outcomes. Objectives: To evaluate the efficacy and safety of Muscle Energy Technique (MET) for people with COPD. Methods: Ten databases were searched from inceptions to May 2018. Eligible studies were randomised controlled trials assessing MET compared to any control for COPD. Outcomes included lung function, exercise capacity, health-related quality of life, and adverse events. Results: Three randomised controlled trials assessing 90 participants were included. The quality of the research was limited by reporting of outcome measures and results, varying treatment protocols, and small sample sizes. Results from one study showed that pulmonary function was not statistically different between groups at end of treatment (FEV1% MD 4.87%; 95% CI - 0.79 to 10.53). Exercise capacity and perceived dyspnoea ratings were improved in single studies. Adverse events were unrelated to the MET intervention. Conclusions: The use of MET for COPD is an emerging field of research, with few studies evaluating its efficacy and safety. Currently, there is insufficient evidence to support the use of MET in the management of COPD. Rigorously designed studies with larger sample sizes are needed to better understand the role of MET for COPD.


Assuntos
Osteopatia , Doença Pulmonar Obstrutiva Crônica/terapia , Adulto , Exercício Físico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculos/metabolismo , Doença Pulmonar Obstrutiva Crônica/metabolismo , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto
5.
Brain Behav ; 8(3): e00888, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29541532

RESUMO

Introduction: Long-lasting experimental muscle pain elicits divergent muscle sympathetic responses, with some individuals exhibiting a persistent increase in muscle sympathetic nerve activity (MSNA), and others a decrease. These divergent responses are thought to result from sustained functional changes in specific brain regions that modulate the cardiovascular responses to pain. Aim: The aim of this study was to investigate brain regions that are functionally coupled to the generation of an MSNA burst at rest and to determine their behavior during tonic muscle pain. Methods: Functional magnetic resonance imaging of the brain was performed concurrently with microelectrode recording of MSNA from the common peroneal nerve during a 40 min infusion of hypertonic saline into the ipsilateral tibialis anterior muscle of 37 healthy human subjects. Results: At rest, blood oxygen level-dependent signal intensity coupled to bursts of MSNA increased in the rostral ventrolateral medulla, insula, dorsolateral prefrontal cortex, posterior cingulate cortex, and precuneus and decreased in the region of the midbrain periaqueductal gray. During pain, MSNA-coupled signal intensity was greater in the region of the nucleus tractus solitarius, midbrain periaqueductal gray, dorsolateral prefrontal, medial prefrontal, and anterior cingulate cortices, than at rest. Conversely, MSNA-coupled signal intensity decreased during pain in parts of the prefrontal cortex. Conclusions: These results suggest that multiple brain regions are recruited in a burst-to-burst manner, and the magnitude of these signal changes is correlated to the overall change in MSNA amplitude during tonic muscle pain.


Assuntos
Encéfalo/fisiopatologia , Músculo Esquelético/inervação , Mialgia/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia , Adolescente , Adulto , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico/métodos , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Nervo Fibular/fisiopatologia , Tempo , Adulto Jovem
6.
Aging Clin Exp Res ; 30(8): 969-975, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29230667

RESUMO

BACKGROUND: In older adults, musculoskeletal pain is associated with increased concerns of falling, reduced balance and increased occurrence of falls. In younger adults, the intensity of neck pain and low back pain is associated with increased postural sway. It is not known if pain further impairs balance and concerns of falling in mobility-limited older adults, and if so, whether this is associated with different intensities of pain. OBJECTIVE: This study examined whether mobility-limited older adults with mild or intense neck pain and/or low back pain have significantly increased postural sway as measured by centre of pressure (COP) changes and concerns of falling compared to those without pain. METHODS: 48 older adults with a gait speed of < 0.9 m/s from Odense, Denmark were recruited through the public health service. Self-reported neck pain, low back pain, and concerns of falling were recorded on questionnaires. Sway range, velocity and area were recorded on a force plate in a comfortable standing stance. Pain intensity was rated on an 11 point numerical rating scale (0-10). Participants were sub-grouped into mild (0-4) and intense (> 5) neck pain or low back pain. RESULTS: Intense neck pain was associated with increased anterior-posterior sway range and area of sway. Intense low back pain was associated with increased concerns of falling. CONCLUSION: Intense neck pain in mobility-limited older adults is associated with significant changes in postural balance, and intense low back pain is associated with significantly higher concerns of falling.


Assuntos
Acidentes por Quedas/estatística & dados numéricos , Dor Lombar/epidemiologia , Dor Musculoesquelética/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Dinamarca , Feminino , Humanos , Vida Independente , Masculino , Equilíbrio Postural , Postura , Pressão , Inquéritos e Questionários
7.
Hum Brain Mapp ; 38(2): 869-881, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27696604

RESUMO

Experimentally induced tonic muscle pain evokes divergent muscle vasoconstrictor responses, with some individuals exhibiting a sustained increase in muscle sympathetic nerve activity (MSNA), and others a sustained decrease. These patterns cannot be predicted from an individual's baseline physiological or psychological measures. The aim of this study was to investigate whether the different muscle sympathetic responses to tonic muscle pain were associated with differential changes in regional brain activity. Functional magnetic resonance imaging (fMRI) of the brain was performed concurrently with microelectrode recording of MSNA from the peroneal nerve during a 40-min infusion of hypertonic saline into the ipsilateral tibialis anterior muscle. MSNA increased in 26 and decreased in 11 of 37 subjects during tonic muscle pain. Within the prefrontal and cingulate cortices, precuneus, nucleus accumbens, caudate nucleus, and dorsomedial hypothalamus, blood oxygen level dependent (BOLD) signal intensity increased in the increasing-MSNA group and remained at baseline or decreased in the decreasing-MSNA group. Similar responses occurred in the dorsolateral pons and in the region of the rostral ventrolateral medulla. By contrast, within the region of the dorsolateral periaqueductal gray (dlPAG) signal intensity initially increased in both groups but returned to baseline levels only in the increasing-MSNA group. These results suggest that the divergent sympathetic responses to muscle pain result from activation of a neural pathway that includes the dlPAG, an area thought to be responsible for the behavioral and cardiovascular responses to psychological rather than physical stressors. Hum Brain Mapp 38:869-881, 2017. © 2016 Wiley Periodicals, Inc.


Assuntos
Encéfalo/fisiopatologia , Mialgia/patologia , Mialgia/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia , Pressão Sanguínea/fisiologia , Encéfalo/diagnóstico por imagem , Potenciais Evocados/fisiologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Oxigênio/sangue , Medição da Dor , Estimulação Física/efeitos adversos , Psicofísica , Respiração , Adulto Jovem
8.
Front Neurol ; 7: 109, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27445972

RESUMO

Acute pain triggers adaptive physiological responses that serve as protective mechanisms that prevent continuing damage to tissues and cause the individual to react to remove or escape the painful stimulus. However, an extension of the pain response beyond signaling tissue damage and healing, such as in chronic pain states, serves no particular biological function; it is maladaptive. The increasing number of chronic pain sufferers is concerning, and the associated disease burden is putting healthcare systems around the world under significant pressure. The incapacitating effects of long-lasting pain are not just psychological - reflexes driven by nociceptors during the establishment of chronic pain may cause serious physiological consequences on regulation of other body systems. The sympathetic nervous system is inherently involved in a host of physiological responses evoked by noxious stimulation. Experimental animal and human models demonstrate a diverse array of heterogeneous reactions to nociception. The purpose of this review is to understand how pain affects the sympathetic nervous system by investigating the reflex cardiovascular and neural responses to acute pain and the long-lasting physiological responses to prolonged (tonic) pain. By observing the sympathetic responses to long-lasting pain, we can begin to understand the physiological consequences of long-term pain on cardiovascular regulation.

9.
Int J Psychophysiol ; 104: 17-23, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27106401

RESUMO

We have recently shown that intramuscular infusion of hypertonic saline, causing pain lasting ~60min, increases muscle sympathetic nerve activity (MSNA) in one group of subjects, yet decreases it in another. Across subjects these divergent sympathetic responses to long-lasting muscle pain are consistent over time and cannot be foreseen on the basis of baseline MSNA, blood pressure, heart rate or sex. We predicted that differences in anxiety or attitudes to pain may account for these differences. Psychometric measures were assessed prior to the induction of pain using the State and Trait Anxiety Inventory (STAI), Pain Vigilance and Awareness Questionnaire (PVAQ), Pain Anxiety Symptoms Scale (PASS) and Pain Catastrophising Scale (PCS); PCS was also administered after the experiment. MSNA was recorded from the common peroneal nerve, before and during a 45-minute intramuscular infusion of hypertonic saline solution into the tibialis anterior muscle of 66 awake human subjects. Forty-one subjects showed an increase in mean burst amplitude of MSNA (172.8±10.6%) while 25 showed a decrease (69.9±3.8%). None of the measured psychological parameters showed significant differences between the increasing and the decreasing groups. We conclude that inter-individual anxiety or pain attitudes do not determine whether MSNA increases or decreases during long-lasting experimental muscle pain in healthy human subjects.


Assuntos
Atitude , Depressão/etiologia , Individualidade , Mialgia/complicações , Mialgia/psicologia , Sistema Nervoso Simpático/fisiopatologia , Adulto , Catastrofização , Depressão/diagnóstico , Feminino , Voluntários Saudáveis , Humanos , Masculino , Mialgia/induzido quimicamente , Medição da Dor , Psicometria , Solução Salina Hipertônica/toxicidade , Adulto Jovem
10.
Front Neurosci ; 9: 471, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26733786

RESUMO

We have previously reported that there are inter-individual differences in the cardiovascular responses to experimental muscle pain, which are consistent over time: intramuscular infusion of hypertonic saline, causing pain lasting ~60 min, increases muscle sympathetic nerve activity (MSNA)-as well as blood pressure and heart rate-in certain subjects, but decrease it in others. Here, we tested the hypothesis that baseline physiological parameters (resting MSNA, heart rate, blood pressure, heart rate variability) determine the cardiovascular responses to long-lasting muscle pain. MSNA was recorded from the common peroneal nerve, together with heart rate and blood pressure, during a 45-min intramuscular infusion of hypertonic saline solution into the tibialis anterior of 50 awake human subjects (25 females and 25 males). Twenty-four subjects showed a sustained increase in mean amplitude of MSNA (160.9 ± 7.3%), while 26 showed a sustained decrease (55.1 ± 3.5%). Between the increasing and decreasing groups there were no differences in baseline MSNA (19.0 ± 1.5 vs. 18.9 ± 1.2 bursts/min), mean BP (88.1 ± 5.2 vs. 88.0 ± 3.8 mmHg), HR (74.7 ± 2.0 vs. 72.8 ± 1.8 beats/min) or heart rate variability (LF/HF 1.8 ± 0.2 vs. 2.2 ± 0.3). Furthermore, neither sex nor body mass index had any effect on whether MSNA increased or decreased during tonic muscle pain. We conclude that the measured baseline physiological parameters cannot account for the divergent sympathetic responses during tonic muscle pain.

11.
Exp Brain Res ; 232(4): 1309-15, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24477764

RESUMO

We recently showed that long-lasting muscle pain, induced by intramuscular infusion of hypertonic saline, evoked two patterns of cardiovascular responses across subjects: one group showed parallel increases in muscle sympathetic nerve activity (MSNA), blood pressure, and heart rate, while the other group showed parallel decreases. Given that MSNA is consistent day to day, we tested the hypothesis that individuals who show increases in MSNA during experimental muscle pain will show consistent responses over time. MSNA was recorded from the peroneal nerve, together with blood pressure and heart rate, during an intramuscular infusion of hypertonic saline causing pain for an hour in 15 subjects on two occasions, 2-27 weeks apart. Pain intensity ratings were not significantly different between the first (5.8 ± 0.4/10) and second (6.1 ± 0.2) recording sessions. While four subjects showed significant decreases in the first session (46.6 ± 9.2% of baseline) and significant increases in the second (159.6 ± 8.9%), in 11 subjects, there was consistency in the changes in MSNA over time: either a sustained decrease (55.6 ± 6.8%, n = 6) or a sustained increase (143.5 ± 6.1%, n = 5) occurred in both recording sessions. There were no differences in pain ratings between sessions for any subjects. We conclude that the changes in MSNA during long-lasting muscle pain are consistent over time in the majority of individuals, reflecting the importance of studying interindividual differences in physiology.


Assuntos
Fibras Adrenérgicas/fisiologia , Músculo Esquelético/fisiologia , Mialgia/fisiopatologia , Adolescente , Fibras Adrenérgicas/efeitos dos fármacos , Adulto , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Feminino , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Humanos , Masculino , Músculo Esquelético/efeitos dos fármacos , Mialgia/induzido quimicamente , Mialgia/diagnóstico , Solução Salina Hipertônica/toxicidade , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/fisiologia , Adulto Jovem
12.
Exp Physiol ; 98(6): 1125-32, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23417691

RESUMO

Experimental pain induced in animals has shown that noxious stimulation of group III and IV afferents increases the firing of muscle spindles via a reflex excitation of fusimotor (γ) motoneurones. Chronic muscle pain has been hypothesized to develop as a result of a vicious cycle involving this mechanism. In order to explore the effects of long-lasting muscle pain on the fusimotor system, single unit muscle spindle afferents were recorded from 15 subjects. Afferent activity was recorded from foot and ankle extensor muscles whilst infusing hypertonic saline into the tibialis anterior muscle of the ipsilateral leg, producing moderate-strong pain lasting for ∼60 min. A change in fusimotor drive was inferred by observing changes in the mean discharge rate of spontaneously active muscle spindle afferents. Homonymous and heteronymous muscles remained relaxed and showed no increase in activity, arguing against any fusimotor-driven increase in motor activity, and there was no net change in the firing of muscle spindle afferents. We conclude that long-lasting stimulation of group III and IV afferents fails to excite fusimotor neurones and increase muscle spindle discharge. Accordingly, the vicious cycle theory has no functional basis for the development of myalgia in human subjects.


Assuntos
Perna (Membro)/fisiologia , Neurônios Motores gama/fisiologia , Músculo Esquelético/fisiologia , Músculo Esquelético/fisiopatologia , Mialgia/fisiopatologia , Adolescente , Adulto , Animais , Estimulação Elétrica/métodos , Feminino , Humanos , Masculino , Contração Muscular/fisiologia , Fusos Musculares/fisiologia , Reflexo/fisiologia , Adulto Jovem
13.
Exp Brain Res ; 221(1): 107-14, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22766847

RESUMO

Skin sympathetic nerve activity (SSNA) controls skin blood flow and sweat release, and acute noxious stimulation of skin has been shown to cause a decrease in SSNA in the anaesthetised or spinal cat. In awake human subjects, acute muscle pain causes a transient rise in SSNA, but the impact of long-lasting (tonic) stimulation of muscle nociceptors on skin sympathetic outflow, blood flow and sweat release is unknown. We tested the hypothesis that tonic stimulation of muscle nociceptors causes a sustained increase in sympathetic outflow to the skin. SSNA was recorded from the common peroneal nerve of 10 awake human subjects. Tonic muscle pain was induced by infusing hypertonic saline (7 %) into the tibialis anterior muscle over ~40 min, titrated to achieve a constant level of muscle pain. SSNA initially increased following the onset of the infusion, reaching a peak of 164 % of baseline within 5 min, but then showed a prolonged and sustained decrease, reaching a nadir of 77 % in 20 min. Conversely, skin blood flow (and vascular conductance) initially decreased, followed by a progressive increase; there were no consistent changes in sweat release. In 9 of 10 subjects, SSNA and skin blood flow were inversely related. We conclude that sympathetic outflow to the skin exhibits a biphasic response to long-lasting stimulation of muscle nociceptors: an initial increase presumably related to the 'arousal' or 'alerting' component of pain, characterised by increased SSNA and decreased skin blood flow, followed by a prolonged decrease in SSNA and increased skin blood flow. The latter may be a purposeful response that contributes to wound healing.


Assuntos
Dor Musculoesquelética/fisiopatologia , Nociceptores/fisiologia , Nervo Fibular/fisiopatologia , Pele/irrigação sanguínea , Pele/inervação , Adulto , Pressão Sanguínea/fisiologia , Feminino , Frequência Cardíaca/fisiologia , Humanos , Injeções Intramusculares/efeitos adversos , Masculino , Dor Musculoesquelética/induzido quimicamente , Medição da Dor , Respiração , Solução Salina Hipertônica/efeitos adversos , Fatores de Tempo , Adulto Jovem
14.
Exp Physiol ; 97(10): 1084-92, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22581744

RESUMO

We recently showed that acute muscle pain, induced by bolus intramuscular injection of hypertonic saline, causes a sustained increase in muscle sympathetic nerve activity (MSNA) and a modest increase in blood pressure and heart rate. However, it is not known whether long-lasting (tonic) pain, which more closely resembles chronic pain, causes a sustained increase in MSNA and blood pressure. We tested this hypothesis by recording MSNA in 12 healthy subjects. Tonic pain was induced for ~60 min by slow intramuscular infusion of hypertonic saline (7%) into the ipsilateral tibialis anterior muscle. Pain was sustained at a tolerable level (5/10 to 6/10 on a visual analog scale). Seven subjects showed progressive increases in mean MSNA amplitude during tonic pain, increasing to 154 ± 17% (SEM) at 45 min and remaining essentially constant for the duration of the infusion. In these subjects, blood pressure and heart rate also increased. Conversely, for the other five subjects MSNA showed a progressive decline, with a peak fall of 67 ± 11% at 40 min; blood pressure and heart rate also fell in these subjects. We conclude that tonic muscle pain has long-lasting effects on the sympathetic control of blood pressure, causing a sustained increase in some subjects yet a sustained decrease in others. This may have implications for individual differences in the cardiovascular consequences of chronic pain.


Assuntos
Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Músculo Esquelético/inervação , Dor/fisiopatologia , Sistema Nervoso Simpático/fisiologia , Adolescente , Adulto , Pressão Sanguínea/efeitos dos fármacos , Fenômenos Fisiológicos Cardiovasculares/efeitos dos fármacos , Sistema Cardiovascular/efeitos dos fármacos , Sistema Cardiovascular/fisiopatologia , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Individualidade , Injeções Intramusculares , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/efeitos dos fármacos , Dor/induzido quimicamente , Solução Salina Hipertônica/farmacologia , Sistema Nervoso Simpático/efeitos dos fármacos , Adulto Jovem
15.
Am J Physiol Heart Circ Physiol ; 302(3): H826-36, 2012 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-22114133

RESUMO

Assessment of spontaneous slow waves in the peripheral blood volume using the photoplethysmogram (PPG) has shown potential clinical value, but the physiological correlates of these fluctuations have not been fully elucidated. This study addressed the contribution of arterial pressure and muscle sympathetic nerve activity (MSNA) in beat-to-beat PPG variability in resting humans under spontaneous breathing conditions. Peripheral PPG waveforms were measured from the fingertip, earlobe, and toe in young and healthy individuals (n = 13), together with the arterial pressure waveform, electrocardiogram, respiration, and direct measurement of MSNA by microneurography. Cross-spectral coherence analysis revealed that among the PPG waveforms, low-frequency fluctuations (0.04-0.15 Hz) in the ear PPG had the highest coherence with arterial pressure (0.71 ± 0.15) and MSNA (0.44 ± 0.18, with a peak of 0.71 ± 0.16 at 0.10 ± 0.03 Hz). The normalized midfrequency powers (0.08-0.15 Hz), with an emphasis on the 0.1-Hz region, were positively correlated between MSNA and the ear PPG (r = 0.77, P = 0.002). Finger and toe PPGs had lower coherence with arterial pressure (0.35 ± 0.10 and 0.30 ± 0.11, respectively) and MSNA (0.33 ± 0.10 and 0.26 ± 0.10, respectively) in the LF band but displayed higher coherence between themselves (0.54 ± 0.09) compared with the ear (P < 0.001), which may suggest the dominance of regional vasomotor activities and a common sympathetic influence in the glabrous skin. These findings highlight the differential mechanisms governing PPG waveform fluctuations across different body sites. Spontaneous PPG variability in the ear includes a major contribution from arterial pressure and MSNA, which may provide a rationale for its clinical utility.


Assuntos
Pressão Sanguínea/fisiologia , Volume Sanguíneo/fisiologia , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/inervação , Fotopletismografia/métodos , Sistema Nervoso Simpático/fisiologia , Adulto , Determinação do Volume Sanguíneo/métodos , Determinação do Volume Sanguíneo/normas , Feminino , Dedos/irrigação sanguínea , Humanos , Modelos Lineares , Masculino , Fotopletismografia/normas , Valores de Referência , Dedos do Pé/irrigação sanguínea , Adulto Jovem
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