Patient-controlled analgesia and intra-operative suggestion

Perception of auditory stimuli during general anesthesia and its effects on patient outcomes: a systematic review and meta-analysis

Purpose

Interest in implicit memory formation and unconscious auditory stimulus perception during general anesthesia has resurfaced as perioperative music has been reported to produce beneficial effects. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating explicit and implicit memory formation during general anesthesia and its effects on postoperative patient outcomes and recovery.

Source

We performed a systematic literature search of Embase, Ovid Medline, and Cochrane Central from inception date until 15 October 2020. Eligible for inclusion were RCTs investigating intraoperative auditory stimulation in adult surgical patients under general anesthesia in which patients, healthcare staff, and outcome assessors were all blinded. We used random effects models for meta-analyses. This study adhered to the PRISMA guidelines and was registered in PROSPERO (CRD42020178087).

Principal findings

Fifty-three (4,200 patients) of 5,859 identified articles were included. There was evidence of implicit memory formation in seven out of 17 studies (41%) when assessed using perceptual priming tasks. Mixed results were observed on postoperative behavioural and motor response after intraoperative suggestions. Intraoperative music significantly reduced postoperative pain (standardized mean difference [SMD], -0.84; 95% confidence interval [CI], -1.1 to -0.57; P < 0.001; I² = 0; n = 226) and opioid requirements (SMD, -0.29; 95% CI, -0.57 to -0.015; P = 0.039; I² = 36; n = 336), while positive therapeutic suggestions did not.

Conclusion

The results of this systematic review and meta-analysis show that intraoperative auditory stimuli can be perceived and processed during clinically adequate, general anesthesia irrespective of surgical procedure severity, leading to implicit memory formation without explicit awareness. Intraoperative music can exert significant beneficial effects on postoperative pain and opioid requirements. Whether the employed intraoperative anesthesia regimen is of influence is not yet clear.

Electronic supplementary material

The online version of this article (10.1007/s12630-021-02015-0) contains supplementary material, which is available to authorized users.

Effect of therapeutic suggestions during general anaesthesia on postoperative pain and opioid use: multicentre randomised controlled trial

OBJECTIVE

To investigate the effect of therapeutic suggestions played to patients through earphones during surgery on postoperative pain and opioid use.

DESIGN

Blinded randomised controlled study.

SETTING

Five tertiary care hospitals in Germany.

PARTICIPANTS

385 of 400 patients consecutively recruited from January to December 2018 who were to undergo surgery for 1-3 hours under general anaesthesia. In the per protocol analysis 191 patients were included in the intervention group and 194 patients in the control group.

INTERVENTION

The intervention comprised an audiotape of background music and positive suggestions based on hypnotherapeutic principles, which was played repeatedly for 20 minutes followed by 10 minutes of silence to patients through earphones during general anaesthesia. Patients in the control group were assigned to a blank tape.

MAIN OUTCOME MEASURES

The main outcome was dose of opioid administered by patient controlled analgesia or nurse controlled analgesia within the first postoperative 24 hours, based on regular evaluation of pain intensity on a numerical rating scale (range 0-10, with higher scores representing more severe pain).

RESULTS

Compared with the control group, the intervention group required a significantly (P=0.002) lower opioid dose within 24 hours after surgery, with a median of 4.0 mg (interquartile range 0-8) morphine equivalents versus 5.3 (2-12), and an effect size (Cohen's d) of 0.36 (95% confidence interval 0.16 to 0.56). The number of patients who needed opioids postoperatively was significantly (P=0.001) reduced in the intervention group: 121 of 191 (63%, 95% confidence interval 45% to 70%) patients in the intervention group versus 155 of 194 (80%, 74% to 85%) in the control group. The number needed to treat to avoid postoperative opioids was 6. Pain scores were consistently and significantly lower in the intervention group within 24 hours after surgery, with an average reduction of 25%. No adverse events were reported.

CONCLUSIONS

Therapeutic suggestions played through earphones during general anaesthesia could provide a safe, feasible, inexpensive, and non-drug technique to reduce postoperative pain and opioid use, with the potential for more general use. Based on the finding of intraoperative perception by a considerable number of patients, surgeons and anaesthetists should be careful about background noise and conversations during surgery.

TRIAL REGISTRATION

German Clinical Trial Register DRKS00013800.

Efficacy of therapeutic suggestions under general anesthesia: a systematic review and meta-analysis of randomized controlled trials

Background

General anesthesia does not block central nervous processing of auditive information. Therefore, positive suggestions even given during surgery might have the potential to encourage well-being and recovery of patients.

Aim of this review was to summarize the evidence on the efficacy of therapeutic suggestions under general anesthesia in adults undergoing surgery compared to an attention control (i.e. white noise).

Methods

We included randomized controlled trials that investigated therapeutic suggestions presented during general anesthesia to adult patients undergoing surgery or medical procedures. Outcomes on pain intensity, mental distress, recovery, use of medication, measured postoperatively within hospitalization were considered. Electronic searches were carried out in the following databases (last search February 23, 2015): MEDLINE, CENTRAL, Web of Science, PsycINFO, ProQuest Dissertations and Theses.

Results

Thirty-two eligible randomized controlled trials were included, comprising a total of 2102 patients. All studies used taped suggestions. Random effects meta-analyses revealed no effects on pain intensity (Hedges’ g = 0.04, CI 95% [−0.04; 0.12], number needed to treat [NNT] = 44.3) and mental distress (g = 0.03, CI 95% [−0.11; 0.16], NNT = 68.2). In contrast, we found small but significant positive effects on use of medication (g = 0.19, CI 95% [0.09; 0.29], NNT = 9.2) and on recovery (g = 0.14, CI 95% [0.03; 0.25], NNT = 13.0). All effects were homogeneous and robust.

Conclusions

Even though effects were small, our results provide indications that intraoperative suggestions can have the potential to reduce the need for medication and enhance recovery. Further high quality trials are needed to strengthen the promising evidence on the efficacy of therapeutic suggestions under general anesthesia for patients undergoing surgery.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-016-0292-0) contains supplementary material, which is available to authorized users.

Effect of wound infiltration with bupivacaine or lower dose bupivacaine/magnesium versus placebo for postoperative analgesia after cesarean section

AIM

The authors examined the analgesic effect of wound infiltration with bupivacaine or lower dose bupivacaine and magnesium versus normal saline for postoperative analgesia after cesarean section.

MATERIALS AND METHODS

A total of 120 patients, American Society of Anesthesiologists (ASA) I-II were prepared for elective cesarean section. At the end of the surgery, the wound was continuously infiltrated at a rate of 5 ml/h for 24 h post-operatively by one of the following solutions: 0.25% bupivacaine, a mixture of 0.125% bupivacaine and 5% magnesium sulphate or normal saline (0.9%). Total opioid consumption, Visual Analogue Scale (VAS) at rest and movement, incidence of opioid side-effects and signs of wound inflammation were assessed during the period of the study (24 h post-operatively). Three months later, residual pain, surgical wound infection, need for extra-antibiotic therapy and wound healing impairment were assessed.

RESULTS

Post-operative pain scores at rest were statistically significant higher in the control group than those in the both wound infiltration groups from 4(th) h and onwards (P < 0.0001). Meanwhile, post-operative pain was higher in bupivacaine group versus magnesium group (P < 0.0001, P < 0.0001, 0.0012, respectively). There was statistically significant increase in VAS during movement in the control group versus others at 2, 4, 12, 24 h post-operatively (P < 0.0001). However, patients received magnesium plus bupivacaine wound infiltration showed a significant decrease in post-operative pain scores than whom received bupivacaine from 4(th) h and onward (P < 0.0001, 0.0054, 0.0001, respectively). Morphine consumption was significantly reduced in the magnesium group, (P < 0.0001). Incidence of residual pain was comparable in the three groups. The incidence of sedation and urine retention were noted to be significantly higher in the control group in comparison to other groups, (P <0.0001). The incidence of post-operative nausea and vomiting was reduced in patients received magnesium plus bupivacaine block versus others (P < 0.0001).

CONCLUSION

Continuous wound infiltration with a mixture of bupivacaine and magnesium sulphate after cesarean section showed an effective analgesia and reduced post-operative Patient Controlled Analgesia (PCA) requirements as compared to continuous wound infiltration with local anesthetic only or placebo with fewer incidences of opioid adverse effects.

Effects of therapeutic suggestion under anesthesia on outcomes in children post tonsillectomy

INTRODUCTION

Tonsillectomy causes discomfort in children. Positive therapeutic suggestions (TS) may be given to patients while they are emerging from general anesthesia as a potential tool to decrease distress.

PURPOSE

This study examined impact of TS on outcomes, when delivered to children emerging from general anesthesia post tonsillectomy.

DESIGN

A double blinded randomized controlled trial was conducted with 94 patient/parent pairs.

METHODS

TS and noise recordings were played via headphones post tonsillectomy upon arrival to the Post Anesthesia Care Unit until the child showed signs of waking.

FINDINGS

Pain scores at 30 minutes post extubation show significantly lower pain in the TS group, P = .04 (Mann Whitney U for independent samples). The TS group had 70% increased likelihood of receiving less intravenous (IV) opioid.

CONCLUSION

TS may help lower pain in children post tonsillectomy and decrease demand for IV opioid pain management in the 4- to 8-year-old tonsillectomy population.

Positive suggestion techniques in somatic medicine: A review of the empirical studies

INTRODUCTION

THERE IS AN EVER REOCCURRING QUESTION IN MEDICAL PRACTICE: Does the positive attitude and communication of the medical staff make any difference?

AIM

Our aim is to present a comprehensive overview of the medically relevant effects of positive suggestions by reviewing the recent literature.

METHODS

We will review the studies measuring the effects of suggestive communication of the past 20 years. In cases of studies presented in more details we quote from the suggestion scripts used in the study, too.

RESULTS

Some of the reviewed papers report that positive suggestions lead to decreased pain and use of pain medication and positively affect physiological factors like bowel motility, blood pressure and bleeding during surgery as well. However, the literature also contains studies in which only partial or no positive effects were found.

CONCLUSIONS

We emphasize further, more detailed investigation of positive suggestion techniques and its integration into the education of medical professionals.

[Positive suggestion techniques in somatic medicine]

There is a re-occurring question in medical practice: do positive attitude and communication of the medical staff make any difference?

AIM

Our aim is to present a comprehensive image of the medically relevant effects of positive suggestions by reviewing the recent literature.

METHODS

We review the studies measuring the effects of suggestive communication of the past 20 years. In cases of studies presented in more details we quote from the suggestion scripts used in the study, too.

RESULTS

Most of the reviewed papers affirm that positive suggestions lead to decreased pain and use of pain medication. But physiological factors like bowel motility, blood pressure and bleeding during surgery can be positively affected, too.

CONCLUSIONS

Suggestive communication - a yet poorly utilized tool - used appropriately can significantly affect healing and recovery of a patient. Thus we emphasize further, more detailed study of this technique and its integration into the education of medical professionals.

Unconscious memory formation during anaesthesia

Do patients form memories of intra-operative events when they are adequately anaesthetized? Studies of memory priming during anaesthesia with depth or awareness monitoring provide some evidence that they do, although only the most basic form of memory function, perceptual priming, persists when patients are unconscious. The probability of memory encoding increases as depth of anaesthesia decreases. There is a theoretical possibility that patients can be adversely affected, through memory priming, by comments made in the operating theatre, and some evidence that positive intra-operative suggestions can benefit patients.

Hypnosis and surgery: past, present, and future

Hypnosis has been defined as the induction of a subjective state in which alterations of perception or memory can be elicited by suggestion. Ever since the first public demonstrations of "animal magnetism" by Mesmer in the 18th century, the use of this psychological tool has fascinated the medical community and public alike. The application of hypnosis to alter pain perception and memory dates back centuries. Yet little progress has been made to fully comprehend or appreciate its potential compared to the pharmacologic advances in anesthesiology. Recently, hypnosis has aroused interest, as hypnosis seems to complement and possibly enhance conscious sedation. Contemporary clinical investigators claim that the combination of analgesia and hypnosis is superior to conventional pharmacologic anesthesia for minor surgical cases, with patients and surgeons responding favorably. Simultaneously, basic research of pain pathways involving the nociceptive flexion reflex and positron emission tomography has yielded objective data regarding the physiologic correlates of hypnosis. In this article I review the history, basic scientific and clinical studies, and modern practical considerations of one of the oldest therapeutical tools: the power of suggestion.

Expression of granulocyte colony-stimulating factor is induced in injured rat carotid arteries and mediates vascular smooth muscle cell migration

Granulocyte colony-stimulating factor (G-CSF) is a lineage-restricted hematopoietic growth factor that stimulates proliferation and maturation of hematopoietic progenitors and is a known powerful mobilizer of bone marrow-derived stem cells. Very little has been reported on G-CSF expression and modulation of vascular smooth muscle cell (VSMC) activation. The purpose of this study was to characterize the expression and effects of G-CSF on primary human VSMC and balloon angioplasty-injured rat carotid arteries. In cultured human VSMC, G-CSF mRNA and protein expression are induced by several cytokines, with the most potent being fetal calf serum and T-lymphocyte-conditioned media. G-CSF is not expressed in naive rat carotid arteries but is induced in neointimal SMC in carotid arteries subject to balloon angioplasty. G-CSF is chemotactic for human VSMC. There is a significant difference between unstimulated cells and those treated with G-CSF at 100 and 1,000 pg/ml (P < 0.01 and 0.05 for 3 experiments). G-CSF also activates the GTPase Rac1, a regulator of cellular migration in VSMC. Inhibition of Rac1 inhibits G-CSF-driven VSMC migration. Important signal transduction protein kinases, including p44/42 MAPK, Akt, and S6 kinase, are also activated in response to G-CSF. This is the first report describing the expression of G-CSF in injured arteries and the multiple effects of G-CSF on VSMC activation. Together, our data suggest that G-CSF is an important mediator of inflammatory cell-VSMC communication and VSMC autocrine activation and may be an important mediator of the VSMC response to injury.