Post-operative fatigue following coronary artery bypass surgery: relationship to emotional state and to the catecholamine response to surgery

Psychological interventions for acute pain after open heart surgery

BACKGROUND

This is an update of a Cochrane review previously published in 2014. Acute postoperative pain is one of the most disturbing complaints in open heart surgery, and is associated with a risk of negative consequences. Several trials investigated the effects of psychological interventions to reduce acute postoperative pain and improve the course of physical and psychological recovery of participants undergoing open heart surgery.

OBJECTIVES

To compare the efficacy of psychological interventions as an adjunct to standard care versus standard care alone or standard care plus attention control in adults undergoing open heart surgery for pain, pain medication, psychological distress, mobility, and time to extubation.

SEARCH METHODS

For this update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Web of Science, and PsycINFO for eligible studies up to February 2017. We used the 'related articles' and 'cited by' options of eligible studies to identify additional relevant studies. We checked lists of references of relevant articles and previous reviews. We searched the ProQuest Dissertations and Theses Full Text Database, ClinicalTrials and the WHO International Clinical Trials Registry Platform to identify any unpublished material or ongoing trials. We also contacted the authors of primary studies to identify any unpublished material. In addition, we wrote to all leading heart centres in Germany, Switzerland, and Austria to check whether they were aware of any ongoing trials.

SELECTION CRITERIA

Randomised controlled trials comparing psychological interventions as an adjunct to standard care versus standard care alone or standard care plus attention in adults undergoing open heart surgery.

DATA COLLECTION AND ANALYSIS

Two review authors (SZ and SK) independently assessed trials for eligibility, estimated the risk of bias and extracted all data. We calculated effect sizes for each comparison (Hedges' g) and meta-analysed data using a random-effects model. We assessed the evidence using GRADE and created 'Summary of findings' tables.

MAIN RESULTS

We added six studies to this update. Overall, we included 23 studies (2669 participants).For the majority of outcomes (two-thirds), we could not perform a meta-analysis since outcomes were not measured, or data were provided by one trial only.No study reported data on the number of participants with pain intensity reduction of at least 50% from baseline. Only one study reported data on the number of participants below 30/100 mm on the Visual Analogue Scale (VAS) in pain intensity (very low-quality evidence). Psychological interventions did not reduce pain intensity in the short-term interval (g 0.39, 95% CI -0.18 to 0.96, 2 studies, 104 participants, low-quality evidence), medium-term interval (g -0.02, 95% CI -0.24 to 0.20, 4 studies, 413 participants, moderate-quality evidence) or in the long-term interval (g 0.05, 95% CI -0.20 to 0.30, 2 studies, 200 participants, moderate-quality evidence).No study reported data on median time to re-medication or on number of participants re-medicated. Only two studies provided data on postoperative analgesic use in the short-term interval, showing that psychological interventions did not reduce the use of analgesic medication (g 1.18, 95% CI -2.03 to 4.39, 2 studies, 104 participants, low-quality evidence). Studies revealed that psychological interventions reduced mental distress in the medium-term (g 0.37, 95% CI 0.13 to 0.60, 13 studies, 1388 participants, moderate-quality evidence) and likewise in the long-term interval (g 0.32, 95% CI 0.10 to 0.53, 14 studies, 1586 participants, moderate-quality evidence). Psychological interventions did not improve mobility in the medium-term interval (g 0.23, 95% CI -0.22 to 0.67, 3 studies, 444 participants, low-quality evidence), nor in the long-term interval (g 0.09, 95% CI -0.10 to 0.28, 4 studies, 458 participants, moderate-quality evidence). Only two studies reported data on time to extubation, indicating that psychological interventions reduced the time to extubation (g 0.56, 95% CI 0.08 to 1.03, 2 studies, 154 participants, low-quality evidence).Overall, the very low to moderate quality of the body of evidence on the efficacy of psychological interventions for acute pain after open heart surgery cannot be regarded as sufficient to draw robust conclusions.Most 'Risk of bias' assessments were low or unclear. We judged selection bias (random sequence generation) and attrition bias to be mostly low risk for included studies. However, we judged the risk of selection bias (allocation concealment), performance bias, detection bias and reporting bias to be mostly unclear.

AUTHORS' CONCLUSIONS

In line with the conclusions of our previous review, there is a lack of evidence to support or refute psychological interventions in order to reduce postoperative pain in participants undergoing open heart surgery. We found moderate-quality evidence that psychological interventions reduced mental distress in participants undergoing open heart surgery. Given the small numbers of studies, it is not possible to draw robust conclusions on the efficacy of psychological interventions on outcomes such as analgesic use, mobility, and time to extubation respectively on adverse events or harms of psychological interventions.

Psychological interventions for acute pain after open heart surgery

BACKGROUND

Acute postoperative pain is one of the most disturbing complaints in open heart surgery, and is associated with a risk of negative consequences. Several trials investigated the effects of psychological interventions to reduce acute postoperative pain and improve the course of physical and psychological recovery of participants undergoing open heart surgery.

OBJECTIVES

To compare the efficacy of psychological interventions as an adjunct to standard care versus standard care alone or standard care plus attention in adults undergoing open heart surgery on pain, pain medication, mental distress, mobility, and time to extubation.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 8), MEDLINE (1946 to September 2013), EMBASE (1980 to September 2013), Web of Science (all years to September 2013), and PsycINFO (all years to September 2013) for eligible studies. We used the 'related articles' and 'cited by' options of eligible studies to identify additional relevant studies. We also checked lists of references of relevant articles and previous reviews. We also searched the ProQuest Dissertations and Theses Full Text Database (all years to September 2013) and contacted the authors of primary studies to identify any unpublished material.

SELECTION CRITERIA

Randomised controlled trials comparing psychological interventions as an adjunct to standard care versus standard care alone or standard care plus attention in adults undergoing open heart surgery.

DATA COLLECTION AND ANALYSIS

Two review authors (SK and JR) independently assessed trials for eligibility, estimated the risk of bias and extracted all data. We calculated effect sizes for each comparison (Hedges' g) and meta-analysed data using a random-effects model.

MAIN RESULTS

Nineteen trials were included (2164 participants).No study reported data on the number of participants with pain intensity reduction of at least 50% from baseline. Only one study reported data on the number of participants below 30/100 mm on the Visual Analogue Scale (VAS) in pain intensity. Psychological interventions have no beneficial effects in reducing pain intensity measured with continuous scales in the medium-term interval (g -0.02, 95% CI -0.24 to 0.20, 4 studies, 413 participants, moderate quality evidence) nor in the long-term interval (g 0.12, 95% CI -0.09 to 0.33, 3 studies, 280 participants, low quality evidence).No study reported data on median time to remedication or on number of participants remedicated. Only one study provided data on postoperative analgesic use. Studies reporting data on mental distress in the medium-term interval revealed a small beneficial effect of psychological interventions (g 0.36, 95% CI 0.10 to 0.62, 12 studies, 1144 participants, low quality evidence). Likewise, a small beneficial effect of psychological interventions on mental distress was obtained in the long-term interval (g 0.28, 95% CI 0.05 to 0.51, 11 studies, 1320 participants, low quality evidence). There were no beneficial effects of psychological interventions on mobility in the medium-term interval (g 0.23, 95% CI -0.22 to 0.67, 3 studies, 444 participants, low quality evidence) nor in the long-term interval (g 0.29, 95% CI -0.14 to 0.71, 4 studies, 423 participants, low quality evidence). Only one study reported data on time to extubation.

AUTHORS' CONCLUSIONS

For the majority of outcomes (two-thirds) we could not perform a meta-analysis since outcomes were not measured, or data were provided by one trial only. Psychological interventions have no beneficial effects on reducing postoperative pain intensity or enhancing mobility. There is low quality evidence that psychological interventions reduce postoperative mental distress. Due to limitations in methodological quality, a small number of studies, and large heterogeneity, we rated the quality of the body of evidence as low. Future trials should measure crucial outcomes (e.g. number of participants with pain intensity reduction of at least 50% from baseline) and should focus to enhance the quality of the body of evidence in general. Altogether, the current evidence does not clearly support the use of psychological interventions to reduce pain in participants undergoing open heart surgery.

Effect of anti-anxiety treatment on sevoflurane requirement and postoperative recovery in patients undergoing radical gastrectomy

AIM: To investigate the effect of anti-anxiety treatment with lorazepam and midazolam on sevoflurane requirement and postoperative recovery in patients undergoing radical gastrectomy.

METHODS: Sixty patients undergoing radical gastrectomy were divided into two groups: observation group and control group. The observation group was administered with lorazepam the night before surgery and midazolam 40 min before the induction of anesthesia, while the control group was not given such drugs. BIS monitoring was used to control the depth of anesthesia. The Spielberger State-Trait Anxiety Inventory (STAI) scores were obtained preoperatively, while the requirement of sevoflurane during operation and the VAS scores 2 h, 6 h and 24 h postoperatively were also calculated.

RESULTS: The observation group had lower STAI scores (S-AI: 53.6 ± 4.45 vs 62.70 ± 3.98, P < 0.05; T-AI: 54.78 ± 3.97 vs 65.65 ± 4.21, P < 0.05) and less requirement of sevoflurane during operation (34.7 ± 0.46 vs 36.2 ± 0.44, P < 0.05). The VAS scores at 6 and 24 hours postoperatively were lower in the observation group (6 h: 3.45 ± 1.60 vs 4.89 ± 1.91, P < 0.05; 24 h: 3.51 ± 1.76 vs 5.17 ± 1.71, P < 0.05) than in the control group. There were no significant differences in awaking time and extubation time between the two groups (both P > 0.05).

CONCLUSION: Combined use of lorazepam and midazolam can reduce preoperative anxiety, intraoperative sevoflurane requirement, and postoperative pain in patients undergoing radical gastrectomy.

Symptoms of fatigue and depression in ischemic heart disease are driven by personality characteristics rather than disease stage: a comparison of CAD and CHF patients

Background

Symptoms of fatigue and depression are prevalent across stages of ischemic heart disease (IHD). We examined (i) the effect of both the IHD stage and type-D personality on fatigue and depressive symptoms at 12-month follow-up, and (ii) whether the effect of type-D personality on these symptoms is moderated by IHD stage.

Methods

Two different samples of patients were included to represent IHD stage: 401 percutaneous coronary intervention patients (early-stage IHD) and 105 ischemic chronic heart failure patients (end-stage IHD) completed the DS14 Type-D Scale at baseline. Logistic regression analysis was used to examine the impact of IHD stage and type-D personality on fatigue and depression at follow-up.

Results

Disease stage was neither associated with symptoms of fatigue ( P = 0.99) nor depression ( P = 0.29) at 12 months. In contrast, type-D personality was shown to predict both symptoms of fatigue [odds ratio (OR) = 2.96; 95% confidence interval (CI): 1.92–4.58, P < 0.001] and depression (OR = 4.91; 95% CI: 3.16–7.65, P < 0.001) at follow-up; the effect of type-D personality on these symptoms was not moderated by disease stage. In multivariable analysis, type-D remained a significant predictor of symptoms of fatigue (OR = 3.14; 95% CI: 1.98–4.99, P < 0.001) and depression (OR = 5.90; 95% CI: 3.60–9.67, P < 0.001), also after controlling for symptom levels at baseline.

Conclusion

Type-D personality but not disease stage predicted symptoms of fatigue and depression at 12-month follow-up.

Preoperative psychological preparation of the child for surgery: an update

Preoperative anxiety is associated with a number of poor postoperative outcomes and with significant parental and child distress before surgery. Preparing children for surgery can prevent many behavioral and physiologic manifestations of anxiety. Psychologic and behavioral interventions and pharmacologic interventions are available to treat preoperative anxiety in children. This article discusses the psychologic preparation of children for surgery.

Presurgery distress and specific response expectancies predict postsurgery outcomes in surgery patients confronting breast cancer

Prior to scheduled surgery, patients frequently experience particularly high levels of distress and expect a variety of postsurgery symptoms. Surgery patients who confront breast cancer are no exception. It has been suggested that such presurgery distress and response expectancies are predictive of postsurgery outcomes. To test the contribution of presurgery distress and expectancies to common postsurgery symptom outcomes (pain, nausea, fatigue, and discomfort), 63 female patients undergoing breast cancer surgery were recruited to a prospective study. Results indicated that presurgery distress uniquely contributed to patients' postsurgery nausea, fatigue, and discomfort; specific expectancies uniquely contributed to pain intensity, pain unpleasantness, and fatigue (ps < .05). Consistent with expectancy theory, associations between response expectancies and postsurgery outcomes were not due to presurgery distress.

Biochemical markers for post-operative fatigue after major surgery

OBJECTIVE

To establish a link between tryptophan (a precursor for 5-hydroxytryptamine (5-HT) or serotonin, involved in sleep and fatigue) and post-operative fatigue after major surgery.

BACKGROUND

There is a link between tryptophan (the precursor for the neurotransmitter 5-hydroxytryptamine), and its competitive binding with non-esterified fatty acids (NEFA) to albumin in the blood. An increase in the plasma concentration of free tryptophan can lead to an increased rate of synthesis of 5-HT in the brain. Free tryptophan competes with the branched chain amino acids (BCAA) for the same port of entry across the blood-brain barrier. It is suggested that the plasma concentration of these amino acids could be a marker of post-operative fatigue. In a previous study undertaken in this laboratory on patients undergoing two different types of major surgery, similar post-operative increases were observed in the plasma concentration of free tryptophan and the plasma concentration ratio of free tryptophan to branched chain amino acids. However, the study was retrospective and no measure of fatigue had been made.

METHODS

In the present study, this deficiency has been addressed by administering a modified Profile of Mood States questionnaire to patients undergoing reconstructive or colorectal surgery. In addition, blood samples were measured for plasma free tryptophan, albumin, NEFA and branched chain amino acids before and on 2 days after surgery.

RESULTS

There was a significant correlation between fatigue scores and plasma free tryptophan (P<0.000), and the plasma concentration ratio of free tryptophan/BCAA (P<0.016) after surgery in all the patients studied (n=34). This correlation was more marked in the colorectal-surgery patients, in whom surgery was more severe. In the three categories of patients receiving elective reconstructive surgery (n=24), those having breast reductions (n=6) had a lower plasma concentration of NEFA and appeared to recover from fatigue more quickly than those with pre-tibial lacerations or malignant melanoma.

CONCLUSIONS

These data provide further evidence of a possible biochemical mechanism for central fatigue which involves a precursor of 5-HT. The provision of branched chain amino acids may help to combat the surge in free tryptophan that occurs during stress such as major surgery.

Depression predicts revascularization procedures for 5 years after coronary angiography

OBJECTIVE

Depression has been reported to increase cardiac event rates and functional impairment in patients with coronary disease. This article describes the impact of depression on subsequent healthcare utilization for such patients.

METHODS

One hundred ninety-eight health maintenance organization patients with stable coronary disease were interviewed after elective angiography using a structured psychiatric diagnostic scale. Cardiac events, hospitalizations, procedures, and costs were monitored for the next 5 years through automated data. Subjects were classified at the time of angiography by modified DSM-IV criteria into those with major, minor, and no depression.

RESULTS

In univariate analyses, the no depression group (N = 136) was most likely to receive coronary artery bypass grafting (CABG) (61% vs. 36% in the major depression group vs. 27% in the minor depression group, p =.001), and the major depression group (N = 25) was most likely to receive percutaneous transluminal coronary angioplasty (PTCA) (44% vs. 14% in the minor depression group vs. 24% in the no depression group). The minor depression group (N = 37) was least likely to be hospitalized for cardiac reasons during follow-up (54% vs. 80% in the major depression group vs. 80% in the no depression group, p =.005). Five-year rates of myocardial infarction and death did not differ significantly between groups. Proportional hazard models showed that those in the depression groups differed in time from catheterization to CABG (chi2(2) = 11.9, p =.003) and time to PCTA (chi2(2) = 7.74, p =.02) after controlling for relevant covariates. Median regression showed that patients with no depression had higher costs during the first year but tended to have lower costs in years 2 through 5 than patients with minor or major depression.

CONCLUSIONS

Depression status at angiography is associated with the need for revascularization and total healthcare costs for the following year.

Presurgical depression predicts medical morbidity 6 months after coronary artery bypass graft surgery

OBJECTIVE

Depression has been related to poor medical prognosis in patients with coronary artery disease and to diminished quality of life after coronary artery bypass graft surgery (CABG). However, prior studies have not fully examined the impact of depression on medical outcomes after CABG. The purpose of this study was to determine the independent contribution of presurgical depression to short-term medical outcome after CABG.

METHODS

Medical, surgical, and psychosocial risk factors were assessed before surgery in 89 male veterans undergoing CABG. In addition, patients completed the Beck Depression Inventory. Medical, surgical, and psychological/quality-of-life outcomes were determined at 6 months of follow-up by telephone interview and review of medical records.

RESULTS

Of the 89 patients studied, 25 scored 10 or greater on the Beck Depression Inventory. The study population was dichotomized on the basis of this cutoff point. A medical prediction model was developed for each outcome of interest, based on the range of medical, surgical, and psychosocial risk indices assessed. The dichotomized depression index was added to these prediction models as a final step. This depression index was found to independently predict cardiac hospitalizations at 6 months (chi(2) = 4.24, p <.04), continued surgical pain at 6 months (chi(2) = 6.36, p <.01), and failure to return to previous activity at 6 months (chi(2) = 15.04, p <.0001). Presurgical depression also predicted depressed affect at 6 months (chi(2) = 13.16, p <.0003).

CONCLUSIONS

Depression is an important independent contributor to medical and psychosocial morbidity up to 6 months after CABG. These findings warrant replication with larger and more diverse populations.

Physiological and psychological influences on postoperative fatigue

Fatigue is common after major surgery and delays recovery. We studied the role of physiological and psychological factors in determining fatigue and physical well being after surgery in 102 patients undergoing primary hip arthroplasty. Self-administered questionnaires were used to measure the intensity of feelings of fatigue, vigor, depression, and subjective physical well being on the day before surgery, on the third and seventh postoperative days, and 1 and 6 mo after surgery. The physiological response to surgery was determined by sequential measurements of circulating norepinephrine, epinephrine, cortisol, interleukin-6, and C-reactive protein during the 7 days after surgery. The peak value of each variable was used for statistical analysis. Physical well being decreased significantly at 3 and 7 days but increased significantly at 1 and 6 mo. Fatigue decreased significantly at 1 and 6 mo. Multiple regression analysis showed that the main predictor of worse physical well being at 3 days was the size of the C-reactive protein response. Subsequently, the main predictor was the level of preoperative well being. The severity of fatigue and vigor after surgery were predicted mostly by the preoperative levels of the respective variable. We conclude that fatigue after hip arthroplasty was not predicted by physiological variables but was largely predicted by preoperative levels of fatigue.

IMPLICATIONS

Fatigue is common after major surgery and delays recovery. It is usually attributed to the physiological response to surgery. We studied patients undergoing hip arthroplasty and found that the severity of postoperative fatigue was not predicted by physiological changes. Instead, it was predicted by the preoperative level of fatigue.

Systematic review and meta-analysis of interventions for postoperative fatigue

BACKGROUND

Postoperative fatigue is common, even after uncomplicated operations. Various theories have been presented regarding its aetiology, each suggesting different possible interventions. The purpose of this review was to identify all studies that have assessed interventions for postoperative fatigue and to evaluate these interventions using meta-analytical techniques.

METHODS

Randomized controlled trials of interventions, identified from a systematic search of relevant databases, were evaluated according to standardized criteria and categorized according to intervention modality. Data relating to the efficacy of each intervention at four different postoperative time-points were collated and data synthesis by meta-analysis was performed.

RESULTS

Analgesia is effective in reducing fatigue immediately after operation. Perioperative administration of human growth hormone reduces fatigue between 8 and 30 days after abdominal surgery. Weaker evidence was found to suggest an influence of glucocorticoid administration and of surgical technique on fatigue in the first week after operation. No evidence was found to support the theory that psychosocial or nutritional interventions affect the symptom.

CONCLUSION

While the results demonstrate that improved analgesia can attenuate immediate postoperative fatigue in most patient groups, further research is needed to determine whether the efficacy of human growth hormone and glucocorticoids extends beyond abdominal surgery. The paucity of research into cognitive-behavioural, sleep and activity-based interventions also needs to be addressed.

Fear and anxiety in patients awaiting coronary artery bypass grafting

OBJECTIVE

The purpose of this study was to identify the prevalence of fear and anxiety in patients awaiting coronary artery bypass grafting and the factors associated with high fear and high anxiety.

DESIGN

The survey included 240 patients placed on the waiting list for coronary artery bypass grafting at one hospital.

SUBJECTS

Two hundred and seven patients completed the questionnaire.

INSTRUMENTS

The Bypass Grafting Fear Scale, the State-Trait Anxiety Inventory, and the Hospital Anxiety and Depression Scale were used.

RESULTS

Half of the patients experienced low fear and anxiety. Twenty-five percent had high fear, but only 5% had high anxiety. Patients who felt high fear were mainly women, had no vocational education, were on sick leave, were depressed, had a tendency towards anxiety, and had a short wait for operation. Patients who displayed medium or high anxiety were mostly under 55 years of age and had depression, but only low or no pain.

CONCLUSIONS

The results facilitate better identification of predictors of high fear and anxiety as well as direct support and information for those patients.

Postoperative fatigue is a component of the emotional response to surgery: results of multivariate analysis

OBJECTIVE

To test the theory that postoperative fatigue is an aspect of the emotional, not physiological, response to surgery, we examined whether fatigue is a component of subjective experience after surgery and whether it is related to subjective physical or emotional state.

METHODS

Patients (N=160) undergoing hip or knee arthroplasty were assessed preoperatively, 1 and 7 days and 1 and 6 months postoperatively using multiple indicators of fatigue and subjective emotional and physical state. Covariance structure modeling was used to find out the structure of patients' experience on each occasion.

RESULTS

At each time, data indicated four latent variables: negative mood, positive mood, dysfunction and pain. Scales measuring fatigue indicated negative or positive mood but were unrelated to dysfunction and pain.

DISCUSSION

In surgical patients, the language of fatigue and energy describes empirically distinct components of emotional state. Explanations for postoperative fatigue should therefore be sought in emotional, not physiological, mechanisms.

Coronary artery bypass graft surgery patients and their family member caregivers: outcomes of a family-focused staged psychoeducational intervention

This experimental study examined the effectiveness of a psychoeducational intervention delivered over 12 weeks. The sample was comprised of 38 coronary artery bypass graft (CABG) surgery patient-family member caregiver dyads who completed all six data collection points. Experimental and control groups did not differ in emotional health, functional health status, or satisfaction. Differences in the number of self-reported complications/symptoms were not in the predicted direction. Improvement occurred in clinical, functional, and emotional outcomes; however, several symptoms, such as fatigue and pain, persisted. Family caregivers reported more depressive symptoms than patients preoperatively and at later stages of recovery. Implications include the need for instruction about the recovery trajectory and adequate preparation and support of home health nurses and family caregivers.

How gender affects psychological adjustment one year after coronary artery bypass graft surgery

This research investigated gender differences in psychological adjustment among patients (112 males, 39 females) one year after coronary artery bypass graft surgery (CABG). Information regarding post-CABG depression, non-cardiac chronic conditions, and socioeconomic variables were obtained from a survey. Additional cardiac, surgical, and demographic data were retrieved from a hospital computer database. Women were more likely than men to experience postoperative depression, attributable to their poor health. Depression one year post-CABG was predicted by non-cardiac chronic illnesses, postoperative fatigue and shortness of breath and socioeconomic status.

A theory of postoperative fatigue

The concept of fatigue has entered medicine from other disciplines in which the term refers to weakening of a material by demands put upon it. Its application to the behavioural and subjective changes that characterize postoperative convalescence has led to the assumption that these changes reflect the physiological and metabolic consequences of surgery. Because evidence does not support this view, we outline a new theory in which postoperative fatigue is the product of physiological, psychological and cultural factors. This theory leads to novel predictions that can be tested in future clinical research. Of particular interest will be the evaluation of systematic attempts to change patient and staff expectations about postoperative convalescence.

A theory of postoperative fatigue: an interaction of biological, psychological, and social processes

The concept of postoperative fatigue has been developed to explain the feelings of malaise and the reduction in activity during the convalescent period that follows surgery in humans. Fatigue has been assumed to reflect the degree of surgical trauma and to be a consequence of muscle weakness caused by physiological sequelae of the trauma. The evidence is inconsistent with this reductionist view. Instead we propose a theory that postoperative fatigue is based on an emotional and motivational change that has the function of ensuring inactivity so as to preserve homeostasis in vital systems in response to injury while preserving the physical capacity to respond to new challenge. This response, triggered by the patient's perception of the surgical stimulus, is prolonged by the influence of staff and patient expectations, which, in turn, reflect cultural beliefs in the necessity of convalescence. This theory can be tested by manipulation of clinical practice at pharmacological and psychological levels.

Changes in the albumin binding of tryptophan during postoperative recovery: a possible link with central fatigue?

Tryptophan is the precursor of the neurotransmitter 5-hydroxytryptamine (5-HT), known to be involved in sleep and fatigue. In the blood, tryptophan binds to albumin, and that which does not, free tryptophan, competes with branched chain amino acids (BCAA) for entry into the brain. The plasma concentrations of albumin, free tryptophan, total tryptophan, and BCAA were measured before and after major surgery in nine elderly and nine coronary artery bypass graft (CABG) patients. In both the elderly and the CABG patients plasma free tryptophan concentrations were increased after surgery, compared with baseline levels; the plasma free tryptophan/BCAA concentration ratio was also increased significantly after surgery. Plasma albumin concentrations were decreased significantly after surgery in both the elderly and the CABG patients. Plasma BCAA concentrations were not affected by surgery in either group. The effect of exercising to exhaustion on 5-HT and tryptophan were investigated in Nagase analbuminemic rats (NAR). The intrasynaptosomal concentration of tryptophan, 5-hydroxy-tryptophan, and 5-HT was increased by fatigue after exercise. In addition, running time to exhaustion was shortened in NAR. These data suggest that free tryptophan uptake and 5-HT synthesis were enhanced in the nerve terminal. A decrease in plasma albumin may account for the increase in plasma-free tryptophan levels. An increase in plasma free tryptophan, resulting in an enhanced plasma concentration ratio of free tryptophan/BCAA, may lead to a higher 5-HT concentration in some parts of the brain and, consequently, to central fatigue. It is suggested that provision of BCAA as a dietary supplement may counteract the increase in plasma free tryptophan and thus improve the status of some patients after major surgery.

Fatigue after major joint arthroplasty: relationship to preoperative fatigue and postoperative emotional state

Fatigue has been widely assumed to increase after major surgery, and possible physical explanations have been intensively investigated. Nevertheless, existing data are almost exclusively from abdominal surgery and are based on the use of a single visual analogue scale. Moreover, no physical basis has been found. The present study used a more homogeneous surgical model than has been employed hitherto in order to find whether fatigue was related to emotional state. We measured fatigue before and 1 and 7 weeks after major joint arthroplasty in 63 patients, using a questionnaire that separates mental and physical fatigue. Physical function and subjective emotional and somatic state were measured at the same times; optimism was measured preoperatively. Neither mental nor physical fatigue increased after this form of surgery. Mental and physical fatigue each correlated with low positive mood throughout. The best predictor of physical fatigue postoperatively and at follow-up was preoperative physical fatigue. Preoperative mental fatigue and negative mood were independent predictors of mental fatigue postoperatively and at follow-up. Preoperative fatigue also predicted worse subjective emotional and physical state after surgery. These results suggest that fatigue should be regarded as an aspect of emotional distress perioperatively and that complaints of fatigue postoperatively may reflect the tendency to complain of fatigue or negative mood preoperatively rather than being attributable to surgical trauma.