Placebo and endogenous mechanisms of analgesia

Neurobiological reduction: From cellular explanations of behavior to interventions

Scientific reductionism, the view that higher level functions can be explained by properties at some lower-level or levels, has been an assumption of nervous system analyses since the acceptance of the neuron doctrine in the late 19th century, and became a dominant experimental approach with the development of intracellular recording techniques in the mid-20th century. Subsequent refinements of electrophysiological approaches and the continual development of molecular and genetic techniques have promoted a focus on molecular and cellular mechanisms in experimental analyses and explanations of sensory, motor, and cognitive functions. Reductionist assumptions have also influenced our views of the etiology and treatment of psychopathologies, and have more recently led to claims that we can, or even should, pharmacologically enhance the normal brain. Reductionism remains an area of active debate in the philosophy of science. In neuroscience and psychology, the debate typically focuses on the mind-brain question and the mechanisms of cognition, and how or if they can be explained in neurobiological terms. However, these debates are affected by the complexity of the phenomena being considered and the difficulty of obtaining the necessary neurobiological detail. We can instead ask whether features identified in neurobiological analyses of simpler aspects in simpler nervous systems support current molecular and cellular approaches to explaining systems or behaviors. While my view is that they do not, this does not invite the opposing view prevalent in dichotomous thinking that molecular and cellular detail is irrelevant and we should focus on computations or representations. We instead need to consider how to address the long-standing dilemma of how a nervous system that ostensibly functions through discrete cell to cell communication can generate population effects across multiple spatial and temporal scales to generate behavior.

General anesthetics activate a potent central pain-suppression circuit in the amygdala

General anesthesia (GA) can produce analgesia (loss of pain) independent of inducing loss of consciousness, but the underlying mechanisms remain unclear. We hypothesized that GA suppresses pain in part by activating supraspinal analgesic circuits. We discovered a distinct population of GABAergic neurons activated by GA in the mouse central amygdala (CeA_GA neurons). In vivo calcium imaging revealed that different GA drugs activate a shared ensemble of CeA_GA neurons. CeA_GA neurons also possess basal activity that mostly reflects animals' internal state rather than external stimuli. Optogenetic activation of CeA_GA potently suppressed both pain-elicited reflexive and self-recuperating behaviors across sensory modalities and abolished neuropathic pain-induced mechanical (hyper-)sensitivity. Conversely, inhibition of CeA_GA activity exacerbated pain, produced strong aversion and canceled the analgesic effect of low-dose ketamine. CeA_GA neurons have widespread inhibitory projections to many affective pain-processing centers. Our study points to CeA_GA as a potential powerful therapeutic target for alleviating chronic pain.

Open-label dose-extending placebos for opioid use disorder: a protocol for a randomised controlled clinical trial with methadone treatment

INTRODUCTION

More than 2 million individuals in the USA have an opioid use disorder (OUD). Methadone maintenance treatment is the gold standard of medication-based treatment for OUD, but high-dose methadone is associated with cardiotoxicity and respiratory complications, among other side effects. These adverse effects make enhancing the effectiveness of lower doses of methadone an attractive therapeutic goal. Long recognised for its capacity to enhance treatment outcomes for a wide range of neuropsychiatric disorders including pain, the placebo effect offers an as-yet untested avenue to such an enhancement. This approach is particularly compelling given that individuals with substance use disorder tend to have higher salience attribution and may thereby be more sensitive to placebo effects. Our study combines two promising clinical methodologies-conditioning/dose-extension and open-label placebo-to investigate whether placebo effects can increase the effective potency of methadone in treatment-seeking OUD patients.

METHODS AND ANALYSIS

A total of 120 newly enrolled treatment-seeking OUD patients will be randomly assigned to one of two different groups: either methadone plus daily placebo dose-extension (PDE; treatment group) or methadone/treatment as usual (control). Participants will meet with study team members five times over the course of 3 months of treatment with methadone (baseline, 2 weeks, and 1, 2 and 3 months postbaseline). Throughout this study time period, methadone dosages will be adjusted by an addiction clinician blind to patient assignment, per standard clinical methods. The primary outcome is methadone dose at 3 months. Secondary outcomes include self-report of drug use; 3-month urine toxicology screen results; and treatment retention. Exploratory outcomes include several environmental as well as personality factors associated with OUD and with propensity to demonstrate a placebo effect.

ETHICS AND DISSEMINATION

Human subjects oversight for this study is provided by the University of Maryland, Baltimore and University of Maryland, College Park Institutional Review Boards. Additionally, the study protocol is reviewed annually by an independent Data and Safety Monitoring Board. Study results will be disseminated via research conference presentations and peer-reviewed publications.

TRIAL REGISTRATION NUMBER

NCT02941809.

Pain Modulation: From Conditioned Pain Modulation to Placebo and Nocebo Effects in Experimental and Clinical Pain

Accumulating evidence reveal important applications of endogenous pain modulation assessment in healthy controls and in patients in clinical settings, as dysregulations in the balance of pain modulatory circuits may facilitate pain and promote chronification of pain. This article reviews data on pain modulation, focusing on the mechanisms and translational aspects of pain modulation from conditioned pain modulation (CPM) to placebo and nocebo effects in experimental and clinical pain. The specific roles of expectations, learning, neural and neurophysiological mechanisms of the central nervous system are briefly reviewed herein. The interaction between CPM and placebo systems in pain inhibitory pathways is highly relevant in the clinic and in randomized controlled trials yet remains to be clarified. Examples of clinical implications of CPM and its relationship to placebo and nocebo effects are provided. A greater understanding of the role of pain modulation in various pain states can help characterize the manifestation and development of chronic pain and assist in predicting the response to pain-relieving treatments. Placebo and nocebo effects, intrinsic to every treatment, can be used to develop personalized therapeutic approaches that improve clinical outcomes while limiting unwanted effects.

Interaction of acupuncture treatment and manipulation laterality modulated by the default mode network

Appropriate selection of ipsilateral or contralateral electroacupuncture (corresponding to the pain site) plays an important role in reaching its better curative effect; however, the involving brain mechanism still remains unclear. Compared with the heat pain model generally established in previous study, capsaicin pain model induces reversible cutaneous allodynia and is proved to be better simulating aspects of clinical nociceptive and neuropathic pain. In the current study, 24 subjects were randomly divided into two groups with a 2 × 2 factorial design: laterality (ipsi- or contralateral side, inter-subject) × treatment with counter-balanced at an interval of one week (verum and placebo electroacupuncture, within-subject). We observed subjective pain intensity and brain activations changes induced by capsaicin allodynia pain stimuli before and after electroacupuncture treatment at acupoint LI4 for 30 min. Analysis of variance results indicated that ipsilateral electroacupuncture treatment produced significant pain relief and wide brain signal suppressions in pain-related brain areas compared with contralateral electroacupuncture. We also found that verum electroacupuncture at either ipsi- or contralateral side to the pain site exhibited comparable significant magnitudes of analgesic effect. By contrast, placebo electroacupuncture elicited significant pain reductions only on the ipsilateral rather than contralateral side. It was inferred that placebo analgesia maybe attenuated on the region of the body (opposite to pain site) where attention was less focused, suggesting that analgesic effect of placebo electroacupuncture mainly rely on the motivation of its spatial-specific placebo responses via attention mechanism. This inference can be further supported by the evidence that the significant interaction effect of manipulation laterality and treatment was exclusively located within the default mode network, including the bilateral superior parietal lobule, inferior parietal lobule, precuneus, and left posterior cingulate cortex. It is also proved that disruptions of the default mode network may account for the cognitive and behavioral impairments in chronic pain patients. Our findings further suggested that default mode network participates in the modulation of spatial-oriented attention on placebo analgesia as a mechanism underlying the degree to which treatment side corresponding to the pain.

Validation of a New Placebo Interferential Current Method: A New Placebo Method of Electrostimulation

Objective

The present study aimed to investigate if a new placebo device for interferential current (IFC) that delivers current during only the first 40 seconds of stimulation is effective at promoting adequate subject blinding.

Methods

Seventy-five subjects were recruited and enrolled into three groups: active IFC, inactive placebo, and new placebo. Pressure pain threshold (PPT), cutaneous sensory threshold (CST), and pain intensity were measured before and after the intervention. After the final assessment, the subjects and the investigator who applied the current were asked about the type of stimulation administered.

Results

None of the placebo forms studied resulted in significant changes to PPT, CST, or pain intensity. The subjects stimulated with active IFC at high intensities (> 17 mA) of stimulation showed higher PPT and CST and lower pain intensity than subjects stimulated at low intensities ( p < 0.03). The new placebo method blinded the investigator in 100% of cases of IFC and 60% of subjects stimulated, whereas for inactive placebo, the investigator was blinded at a rate of 0% and 34% of subjects.

Conclusion

The new method of placebo IFC was effective for blinding of research investigators and most of the active IFC-treated subjects, promoting an appropriate placebo method.

Enhanced therapeutic alliance modulates pain intensity and muscle pain sensitivity in patients with chronic low back pain: an experimental controlled study

BACKGROUND

Physical therapy influences chronic pain by means of the specific ingredient of an intervention as well as contextual factors including the setting and therapeutic alliance (TA) between provider and patient.

OBJECTIVE

The purpose of this study was to compare the effect of enhanced versus limited TA on pain intensity and muscle pain sensitivity in patients with chronic low back pain (CLBP) receiving either active or sham interferential current therapy (IFC).

DESIGN

An experimental controlled study with repeated measures was conducted. Participants were randomly divided into 4 groups: (1) AL (n=30), which included the application of active IFC combined with a limited TA; (2) SL (n=29), which received sham IFC combined with a limited TA; (3) AE (n=29), which received active IFC combined with an enhanced TA; and (4) SE (n=29), which received sham IFC combined with an enhanced TA.

METHODS

One hundred seventeen individuals with CLBP received a single session of active or sham IFC. Measurements included pain intensity as assessed with a numerical rating scale (PI-NRS) and muscle pain sensitivity as assessed via pressure pain threshold (PPT).

RESULTS

Mean differences on the PI-NRS were 1.83 cm (95% CI=14.3-20.3), 1.03 cm (95% CI=6.6-12.7), 3.13 cm (95% CI=27.2-33.3), and 2.22 cm (95% CI=18.9-25.0) for the AL, SL, AE, and SE groups, respectively. Mean differences on PPTs were 1.2 kg (95% CI=0.7-1.6), 0.3 kg (95% CI=0.2-0.8), 2.0 kg (95% CI=1.6-2.5), and 1.7 kg (95% CI=1.3-2.1), for the AL, SL, AE, and SE groups, respectively.

LIMITATIONS

The study protocol aimed to test the immediate effect of the TA within a clinical laboratory setting.

CONCLUSIONS

The context in which physical therapy interventions are offered has the potential to dramatically improve therapeutic effects. Enhanced TA combined with active IFC appears to lead to clinically meaningful improvements in outcomes when treating patients with CLBP.

Trial of repeated analgesia with Kangaroo Mother Care (TRAKC Trial)

BACKGROUND

Skin-to-skin contact (SSC) between mother and infant, commonly referred to as Kangaroo Mother Care (KMC), is recommended as an intervention for procedural pain. Evidence demonstrates its consistent efficacy in reducing pain for a single painful procedure. The purpose of this study is to examine the sustained efficacy of KMC, provided during all routine painful procedures for the duration of Neonatal Intensive Care Unit (NICU) hospitalization, in diminishing behavioral pain response in preterm neonates. The efficacy of KMC alone will be compared to standard care of 24% oral sucrose, as well as the combination of KMC and 24% oral sucrose.

METHODS/DESIGN

Infants admitted to the NICU who are less than 36 6/7 weeks gestational age (according to early ultrasound), that are stable enough to be held in KMC, will be considered eligible (N = 258). Using a single-blinded randomized parallel group design, participants will be assigned to one of three possible interventions: 1) KMC, 2) combined KMC and sucrose, and 3) sucrose alone, when they undergo any routine painful procedure (heel lance, venipuncture, intravenous, oro/nasogastric insertion). The primary outcome is infant's pain intensity, which will be assessed using the Premature Infant Pain Profile (PIPP). The secondary outcome will be maturity of neurobehavioral functioning, as measured by the Neurobehavioral Assessment of the Preterm Infant (NAPI). Gestational age, cumulative exposure to KMC provided during non-pain contexts, and maternal cortisol levels will be considered in the analysis. Clinical feasibility will be accounted for from nurse and maternal questionnaires.

DISCUSSION

This will be the first study to examine the repeated use of KMC for managing procedural pain in preterm neonates. It is also the first to compare KMC to sucrose, or the interventions in combination, across time. Based on the theoretical framework of the brain opioid theory of attachment, it is expected that KMC will be a preferred standard of care. However, current pain management guidelines are based on minimal data on repeated use of either intervention. Therefore, regardless of the outcomes of this study, results will have important implications for guidelines and practices related to management of procedural pain in preterm infants.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01561547.

Placebo and the new physiology of the doctor-patient relationship

Modern medicine has progressed in parallel with the advancement of biochemistry, anatomy, and physiology. By using the tools of modern medicine, the physician today can treat and prevent a number of diseases through pharmacology, genetics, and physical interventions. Besides this materia medica, the patient's mind, cognitions, and emotions play a central part as well in any therapeutic outcome, as investigated by disciplines such as psychoneuroendocrinoimmunology. This review describes recent findings that give scientific evidence to the old tenet that patients must be both cured and cared for. In fact, we are today in a good position to investigate complex psychological factors, like placebo effects and the doctor-patient relationship, by using a physiological and neuroscientific approach. These intricate psychological factors can be approached through biochemistry, anatomy, and physiology, thus eliminating the old dichotomy between biology and psychology. This is both a biomedical and a philosophical enterprise that is changing the way we approach and interpret medicine and human biology. In the first case, curing the disease only is not sufficient, and care of the patient is of tantamount importance. In the second case, the philosophical debate about the mind-body interaction can find some important answers in the study of placebo effects. Therefore, maybe paradoxically, the placebo effect and the doctor-patient relationship can be approached by using the same biochemical, cellular and physiological tools of the materia medica, which represents an epochal transition from general concepts such as suggestibility and power of mind to a true physiology of the doctor-patient interaction.

Are treatments more effective than placebos? A systematic review and meta-analysis

BACKGROUND

Placebos are widely used in clinical practice in spite of ethical restrictions. Whether such use is justified depends in part on the relative benefit of placebos compared to 'active' treatments. A direct test for differences between placebo and 'active' treatment effects has not been conducted.

OBJECTIVES

We aimed to test for differences between treatment and placebo effects within similar trial populations.

DATA SOURCES

A Cochrane Review compared placebos with no treatment in three-armed trials (no treatment, placebo, and treatment). We added an analysis of treatment and placebo differences within the same trials. SYNTHESIS METHODS: For continuous outcomes we compared mean differences between placebo and no treatment with mean differences between treatment and placebo. For binary outcomes we compared the risk ratio for treatment benefit (versus placebo) with the risk ratio for placebo benefit (versus no treatment). We conducted several preplanned subgroup analyses: objective versus subjective outcomes, conditions tested in three or more trials, and trials with varying degrees of bias.

RESULTS

In trials with continuous outcomes (n = 115) we found no difference between treatment and placebo effects (MD = -0.29, 95% CI -0.62 to 0.05, P = 0.10). In trials with binary outcomes (n = 37) treatments were significantly more effective than placebos (RRR = 0.72, 95%CI = 0.61 to 0.86, P = 0.0003). Treatment and placebo effects were not different in 22 out of 28 predefined subgroup analyses. Of the six subgroups with differences treatments were more effective than placebos in five. However when all criteria for reducing bias were ruled out (continuous outcomes) placebos were more effective than treatments (MD = 1.59, 95% CI = 0.40 to 2.77, P = 0.009).

CONCLUSIONS AND IMPLICATIONS

Placebos and treatments often have similar effect sizes. Placebos with comparatively powerful effects can benefit patients either alone or as part of a therapeutic regime, and trials involving such placebos must be adequately blinded.

Modulation of laser-evoked potentials and pain perception by transcutaneous electrical nerve stimulation (TENS): a placebo-controlled study in healthy volunteers

OBJECTIVE

To investigate the effects of transcutaneous electrical nerve stimulation (TENS) on brain nociceptive responses (laser-evoked potentials, LEPs) and pain perception.

METHODS

Twenty healthy subjects were included. Nociceptive CO(2)-laser pulses were sequentially delivered to the dorsum of both feet. The amplitude of LEPs and nociceptive thresholds were collected in three consecutive conditions: T1: "sham" TENS (2 Hz/low-intensity) positioned heterotopically, over the left thigh; T2: "active" TENS (120 Hz/low-intensity) applied homotopically, over the left common peroneal nerve; and T3: "sham" TENS (replication of condition T1).

RESULTS

Compared with "sham" TENS, "active" TENS significantly decreased the LEPs amplitude. This effect was observed exclusively when "active" TENS was applied ipsilaterally to the painful stimulus. Nociceptive thresholds increased with sessions in both limbs, but the increase observed during the "active" condition of TENS (T2) exceeded significantly that observed during the condition T3 only on the foot ipsilateral to TENS.

CONCLUSIONS

Compared with a credible placebo TENS, high-frequency TENS induced a significant attenuation of both the acute pain and LEPs induced by noxious stimuli applied on the same dermatome.

SIGNIFICANCE

This modulation of subjective and objective concomitants of pain processing reflects a real neurophysiological TENS-related effect on nociceptive transmission.

Placebo use in the United kingdom: results from a national survey of primary care practitioners

Objectives

Surveys in various countries suggest 17% to 80% of doctors prescribe ‘placebos’ in routine practice, but prevalence of placebo use in UK primary care is unknown.

Methods

We administered a web-based questionnaire to a representative sample of UK general practitioners. Following surveys conducted in other countries we divided placebos into ‘pure’ and ‘impure’. ‘Impure’ placebos are interventions with clear efficacy for certain conditions but are prescribed for ailments where their efficacy is unknown, such as antibiotics for suspected viral infections. ‘Pure’ placebos are interventions such as sugar pills or saline injections without direct pharmacologically active ingredients for the condition being treated. We initiated the survey in April 2012. Two reminders were sent and electronic data collection closed after 4 weeks.

Results

We surveyed 1715 general practitioners and 783 (46%) completed our questionnaire. Our respondents were similar to those of all registered UK doctors suggesting our results are generalizable. 12% (95% CI 10 to 15) of respondents used pure placebos while 97% (95% CI 96 to 98) used impure placebos at least once in their career. 1% of respondents used pure placebos, and 77% (95% CI 74 to 79) used impure placebos at least once per week. Most (66% for pure, 84% for impure) respondents stated placebos were ethical in some circumstances.

Conclusion and implications

Placebo use is common in primary care but questions remain about their benefits, harms, costs, and whether they can be delivered ethically. Further research is required to investigate ethically acceptable and cost-effective placebo interventions.

Placebo mechanisms across different conditions: from the clinical setting to physical performance

Although the great increase in interest in the placebo phenomenon was spurred by the clinical implications of its use, the progressive elucidation of the neurobiological and pharmacological mechanisms underlying the placebo effect also helps cast new light on the relationship between mind (and brain) and body, a topic of foremost philosophical importance but also a major medical issue in light of the complex interactions between the brain on the one hand and body functions on the other. While the concept of placebo can be a general one, with a broad definition generally applicable to many different contexts, the description of the cerebral processes called into action in specific situations can vary widely. In this paper, examples will be given where physiological or pathological conditions are altered following the administration of an inert substance or verbal instructions tailored to induce expectation of a change, and explanations will be offered with details on neurotransmitter changes and neural pathways activated. As an instance of how placebo effects can extend beyond the clinical setting, data in the physical performance domain and implications for sport competitions will also be presented and discussed.

Placebo analgesia affects the behavioral despair tests and hormonal secretions in mice

RATIONALE

The placebo effect is a fascinating yet puzzling phenomenon, which has challenged investigators over the past 50 years. In previous studies, the investigators only focused on the placebo effect obtained within a single domain, and pain is the field in which most of the placebo research has been performed. However, recent research by our laboratory (Zhang and Luo in Psychophysiology 46:626-634, 2009; Zhang et al. 2011) showed that, in human subjects, the placebo effect can be transferred from one domain to the other, namely from pain to emotion.

OBJECTIVES

The scope of this study was to investigate whether placebo analgesia could affect the depressive behavior in mice.

MATERIALS AND METHODS

Female C57/BL6 mice were trained to associate the context cue with elevated pain tolerance via a set of procedures. Then the forced swim test and tail suspension test were used to measure the depressive-like behaviors on the test day. Plasma concentrations of adrenocorticotropic hormone (ACTH) and corticosterone were also detected.

RESULTS

Our results showed that the placebo analgesia, which was established by a set of procedures in mice, was transferable and could produce a significant antidepressant effect on depressive test. Plasma levels of corticosterone and ACTH further proved that the placebo analgesia that was established from pain-reducing training not only induced a significant placebo effect on pain, but also decreased significantly the hypothalamus-pituitary-adrenal axis (HPA) response to stress and produced a stress-alleviating effect.

CONCLUSIONS

These data show that placebo analgesia affects the behavioral despair tests and hormonal secretions in mice.

Predicting individual differences in placebo analgesia: contributions of brain activity during anticipation and pain experience

Recent studies have identified brain correlates of placebo analgesia, but none have assessed how accurately patterns of brain activity can predict individual differences in placebo responses. We reanalyzed data from two fMRI studies of placebo analgesia (N = 47), using patterns of fMRI activity during the anticipation and experience of pain to predict new subjects' scores on placebo analgesia and placebo-induced changes in pain processing. We used a cross-validated regression procedure, LASSO-PCR, which provided both unbiased estimates of predictive accuracy and interpretable maps of which regions are most important for prediction. Increased anticipatory activity in a frontoparietal network and decreases in a posterior insular/temporal network predicted placebo analgesia. Patterns of anticipatory activity across the cortex predicted a moderate amount of variance in the placebo response (∼12% overall, ∼40% for study 2 alone), which is substantial considering the multiple likely contributing factors. The most predictive regions were those associated with emotional appraisal, rather than cognitive control or pain processing. During pain, decreases in limbic and paralimbic regions most strongly predicted placebo analgesia. Responses within canonical pain-processing regions explained significant variance in placebo analgesia, but the pattern of effects was inconsistent with widespread decreases in nociceptive processing. Together, the findings suggest that engagement of emotional appraisal circuits drives individual variation in placebo analgesia, rather than early suppression of nociceptive processing. This approach provides a framework that will allow prediction accuracy to increase as new studies provide more precise information for future predictive models.

The effect of opioid receptor blockade on the neural processing of thermal stimuli

The endogenous opioid system represents one of the principal systems in the modulation of pain. This has been demonstrated in studies of placebo analgesia and stress-induced analgesia, where anti-nociceptive activity triggered by pain itself or by cognitive states is blocked by opioid antagonists. The aim of this study was to characterize the effect of opioid receptor blockade on the physiological processing of painful thermal stimulation in the absence of cognitive manipulation. We therefore measured BOLD (blood oxygen level dependent) signal responses and intensity ratings to non-painful and painful thermal stimuli in a double-blind, cross-over design using the opioid receptor antagonist naloxone. On the behavioral level, we observed an increase in intensity ratings under naloxone due mainly to a difference in the non-painful stimuli. On the neural level, painful thermal stimulation was associated with a negative BOLD signal within the pregenual anterior cingulate cortex, and this deactivation was abolished by naloxone.

Anti-TNF-alpha treatment for deep endometriosis-associated pain: a randomized placebo-controlled trial

BACKGROUND

Endometriosis is associated with an inflammatory response. Hence infliximab, an anti-TNF-alpha monoclonal antibody, might relieve pain.

METHODS

A randomized placebo-controlled trial was designed with 21 women with severe pain and a rectovaginal nodule of at least 1 cm. After 1 month of observation, three infusions of infliximab (5 mg/kg) or placebo were given. Surgery was performed 3 months later and follow-up continued for 6 months. The primary end-point was pain (dysmenorrhea, deep dyspareunia and non-menstrual pain) rated at each visit by the clinician and on a daily basis by the patient who in addition scored pain by visual analog pain scale and analgesia intake. Secondary end-points included the volume of the endometriotic nodule, pelvic tenderness and the visual appearance of endometriotic lesions at laparoscopy.

RESULTS

Pain severity decreased during the treatment by 30% in both the placebo (P < 0.001) and infliximab groups (P < 0.001). However, no effect of infliximab was observed for any of the outcome measures. After surgery, pain scores decreased in both groups to less than 20% of the initial value.

CONCLUSIONS

Infliximab appears not to affect pain associated with deep endometriosis. Treatment is associated with an important placebo effect. After surgery, pain decreases to less than 20%. Trials registration number ClinicalTrials.gov: NCT00604864.

Communication during induction of paediatric anaesthesia: an observational study

We aimed to identify and categorise advanced communication skills used by experienced consultant paediatric anaesthetists to facilitate the induction of paediatric anaesthesia. The communication techniques were both verbal and non-verbal. Communications with potentially negative effects were also noted. Eighty-three inductions were observed over a three-month period. The 12 anaesthetists observed were all senior consultants at a tertiary referral paediatric centre. The mean age of patients was 6.1 years SD+/-4.8. There were 53 males (63.9%) and 30 females (36.1%). A first anaesthetic was administered to 43 patients (56%) and sedative premedication to six (8%). Inhalational inductions were observed in 59 patients (71%). The remainder received an intravenous induction. Anaesthesia was induced in the operating room on 68 occasions (82%), in the induction room on 11 (13%) and in the radiology department on 4(5%). The most common communication techniques used were: voice change in 60 (72%); distraction in 49 (59%); direct commands in 39 (47%); repetition in 34 (41%); imagery in 21 (25%) and focused attention 21 (25%). Other techniques used were seeding of ideas, utilisation, non-verbal cues, double-binds, story-telling, indirect suggestion, dissociation and reversed effect. Sabotage by parents or staff such as inadvertent negative suggestions, was observed on 14 occasions (17%). Paediatric anaesthetists utilise a wide range of communication techniques in a highly flexible manner when inducing anaesthesia in children. Many of these communications can be characterised as hypnotherapeutic. Our observations suggest that formal structured training in communication skills and further research is warranted.

Effect of communication on pain during intravenous cannulation: a randomized controlled trial

BACKGROUND

Clinicians frequently warn patients of discomfort before potentially painful procedures, despite the lack of evidence that such communications are helpful. We aimed to compare two communications (one with, and the other without, a warning of a 'sting') immediately before i.v. cannulation in order to measure differences in perceived pain by patients during the procedure.

METHODS

Randomly assigned patients awaiting elective surgery received a communication immediately before i.v. cannulation consisting of either 'I am going to apply the tourniquet and insert the needle in a few moments. It's a sharp scratch and it may sting a little' (Group S) or 'I am going to apply the tourniquet on the arm. As I do this many people find the arm becomes heavy, numb and tingly. This allows the drip to be placed more comfortably' (Group NS). Cannulation pain was measured by a 0-10 verbal numerical rating score (VNRS) and five-point Likert scale.

RESULTS

Of 101 participants, 49 were allocated to Group S and 52 to Group NS. Median VNRS pain scores with inter-quartile ranges (IQR) were 1 and 2, respectively, for both groups. Median Likert scores were 3 in Group S and 2 in Group NS with an IQR of 1 for both groups (P = 0.13). Six participants vocalized pain in Group S and none in Group NS (P = 0.01). Three participants withdrew their arm spontaneously in Group S and none in Group NS (P = 0.11).

CONCLUSIONS

Warning patients of a 'sting' before i.v. cannulation may not be helpful.

The effect of physical therapy on beta-endorphin levels

Beta-endorphin (betaE) is an important reliever of pain. Various stressors and certain modalities of physiotherapy are potent inducers of the release of endogenous betaE to the blood stream. Most forms of exercise also increase blood betaE level, especially when exercise intensity involves reaching the anaerobic threshold and is associated with the elevation of serum lactate level. Age, gender, and mental activity during exercise also may influence betaE levels. Publications on the potential stimulating effect of manual therapy and massage on betaE release are controversial. Sauna, mud bath, and thermal water increase betaE levels through conveying heat to the tissues. The majority of the techniques for electrical stimulation have a similar effect, which is exerted both centrally and--to a lesser extent--peripherally. However, the parameters of electrotherapy have not yet been standardised. The efficacy of analgesia and the improvement of general well-being do not necessarily correlate with betaE level. Although in addition to blood, increased brain and cerebrospinal fluid betaE levels are also associated with pain, the majority of studies have concerned blood betaE levels. In general, various modalities of physical therapy might influence endorphin levels in the serum or in the cerebrospinal fluid--this is usually manifested by elevation with potential mitigation of pain. However, a causal relationship between the elevation of blood, cerebrospinal fluid or brain betaE levels and the onset of the analgesic action cannot be demonstrated with certainty.