Intraoperative warming and post-operative cognitive dysfunction after total knee replacement

Postoperative Delirium and Postoperative Cognitive Dysfunction in Patients with Elective Hip or Knee Arthroplasty: A Narrative Review of the Literature

Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are common complications following total knee arthroplasty (TKA) and total hip arthroplasty (THA), affecting the length of hospital stay and increasing medical complications. Although many papers have been published on both conditions in this setting, no reviews have currently been written. Thus, the purpose of our study is to summarize the current literature and provide information about POD and POCD following elective THA or TKA. Our literature search was conducted in the electronic databases PubMed and the Cochrane library. We found that POD is a common complication following elective THA or TKA, with a median incidence of 14.8%. Major risk factors include older age, cognitive impairment, dementia, preoperative (pre-op) comorbidities, substance abuse, and surgery for fracture. Diagnosis can be achieved using tools such as the confusion assessment method (CAM), which is sensitive, specific, reliable, and easy to use, for the identification of POD. Treatment consists of risk stratification and the implementation of a multiple component prevention protocol. POCD has a median incidence of 19.3% at 1 week, and 10% at 3 months. Risk factors include older age, high BMI, and cognitive impairment. Treatment consists of reversing risk factors and implementing protocols in order to preserve physiological stability. POD and POCD are common and preventable complications following TKA and THA. Risk stratification and specific interventions can lower the incidence of both syndromes. Every physician involved in the care of such patients should be informed on every aspect of these conditions in order to provide the best care for their patients.

Gut-Brain Axis: Possible Role of Gut Microbiota in Perioperative Neurocognitive Disorders

Aging is becoming a severe social phenomenon globally, and the improvements in health care and increased health awareness among the elderly have led to a dramatic increase in the number of surgical procedures. Because of the degenerative changes in the brain structure and function in the elderly, the incidence of perioperative neurocognitive disorders (PND) is much higher in elderly patients than in young people following anesthesia/surgery. PND is attracting more and more attention, though the exact mechanisms remain unknown. A growing body of evidence has shown that the gut microbiota is likely involved. Recent studies have indicated that the gut microbiota may affect postoperative cognitive function via the gut-brain axis. Nonetheless, understanding of the mechanistic associations between the gut microbiota and the brain during PND progression remains very limited. In this review, we begin by providing an overview of the latest progress concerning the gut-brain axis and PND, and then we summarize the influence of perioperative factors on the gut microbiota. Next, we review the literature on the relationship between gut microbiota and PND and discuss how gut microbiota affects cognitive function during the perioperative period. Finally, we explore effective early interventions for PND to provide new ideas for related clinical research.

Local Anesthesia and Conscious Sedation Does Not Affect Patient's Mood and Anxiety Levels during Percutaneous Endoscopic Lumbar Diskectomy: A Prospective Study

BACKGROUND AND STUDY AIMS

 Undergoing a surgical procedure can be very stressful for patients and can lead to high anxiety levels during both the preoperative and the postoperative period. Levels of anxiety and fear may depend on multiple factors including the type of anesthesia to be used. The objective of this study is to evaluate whether patient's awareness of the surgical environment in the operating room under local anesthesia and conscious sedation (LACS) affects their mood and anxiety levels.

METHODS

 We performed a prospective study for a series of consecutive patients who underwent transforaminal percutaneous endoscopic lumbar diskectomy (PELD) for the treatment of lumbar disk herniation. The patients completed Profile of Mood States (POMS) and State-Trait Anxiety Inventory (STAI) forms in the preoperative period and in the early postoperative period. We divided the patients into two groups according to the type of anesthesia applied during surgery: LACS and general anesthesia (GA) groups. We compared the preoperative and postoperative POMS and STAI scores between groups and the change of these scores between the preoperative and postoperative periods in each group.

RESULTS

 In this study, we included 30 patients who underwent PELD between May and December 2019 and met the inclusion criteria. The GA group consisted of 16 patients and the LACS group consisted of 14 patients. In each group, POMS and STAI scores decreased in the early postoperative period compared with the preoperative period. We found no significant difference in percentage of POMS and STAI TX-1 score changes between the LACS and GA groups.

CONCLUSION

 The results of our study show that patients' awareness of the surgical environment in the operating room under LACS does not significantly affect their mood and anxiety levels and patients do not seem to endure increased emotional stress during the PELD operation, as compared with PELD operation under GA.

Impact of multimodal warming during general anaesthesia on postoperative cognitive dysfunction in elderly patients with gynaecological cancer: study protocol for a single-blinded randomised controlled trial

BACKGROUND

Cognitive impairment after anaesthesia and surgery is a recognised consequence. This often leads to poor health outcomes and increases healthcare resource utilisation and associated costs, especially in elderly people. However, thus far, there have not been any effective therapies for managing postoperative cognitive dysfunction (POCD). Furthermore, research on the association of multimodal warming with POCD and the clinical outcomes in older patients after gynaecological surgery has not been rigorous. For these reasons, our investigation aims to evaluate whether perioperative multimodal warming would reduce the incidence of POCD and improve prognosis in elderly patients with gynaecological cancer.

METHODS AND ANALYSIS

This is a single-centre, prospective, single-blinded randomised controlled trial. One hundred and fifty patients for gynaecological cancer surgery and 16 non-surgical controls aged 65 years or older will be studied in this trial. A series of neuropsychological tests will be completed to evaluate cognitive function in surgery patients before, at day 7 and 3 months after gynaecological cancer surgery. In addition, POCD and cognitive decline will be assessed using the reliable change index using the control group's results. The primary outcome is the prevalence of POCD in elderly gynaecological cancer surgery patients and association between perioperative multimodal warming and POCD.

ETHICS AND DISSEMINATION

The protocol for this prospective observational study was approved by the ethics committee of the West China Second University Hospital, Sichuan University (NO. KX215). Recruitment will commence in April 2021 and continue to April 2022. The findings of this trial will be disseminated in peer-reviewed journals and scientific meetings.

TRIAL REGISTRATION NUMBER

ChiCTR2100041663.

Reduction of neuroinflammation alleviated mouse post bone fracture and stroke memory dysfunction

Tibia fracture (BF) enhances stroke injury and post-stroke memory dysfunction in mouse. Reduction of neuroinflammation by activation of α-7 nicotinic acetylcholine receptor (α-7 nAchR) reduced acute neuronal injury and sensorimotor dysfunction in mice with BF 1-day after stroke. We hypothesize that reduction of neuroinflammation by activation of α-7 nAchR improves long-term memory function of mice with BF 6-h before stroke. The mice were randomly assigned to saline, PHA-568487 (α-7 nAchR agonist) and methyllycaconitine (antagonist) treatment groups. The sensorimotor function was tested by adhesive removal and corner tests at 3 days, the memory function was tested by Y-maze test weekly for 8 weeks and novel objective recognition test at 8 weeks post-injuries. We found PHA-568487 treatment reduced, methyllycaconitine increased the number of CD68⁺ cells in the peri-infarct and hippocampal regions, neuronal injury in the infarct region, sensorimotor and long-term memory dysfunctions. PHA-568487 treatment also reduced, while methyllycaconitine treatment increased atrophy of hippocampal granule cell layer and white matter damage in the striatum. In addition, PHA-568487 treatment increased neuron proliferation in granule cell layer. Our data indicated that reduction of neuroinflammation through activation of α-7 nAchR decreased neuronal damage, sensorimotor and long-term memory dysfunction of mice with BF shortly before stroke.

Effect of preoperative hospitalisation period on postoperative cognitive dysfunction in patients undergoing hip surgery under regional anaesthesia

AIM OF THE STUDY

The main objective of this prospective and observational study was to investigate the effect of the preoperative hospitalisation period on early postoperative cognitive dysfunction (POCD) development in patients undergoing total hip replacement surgery under regional anaesthesia.

MATERIALS AND METHODS

Between November 2013 and September 2014, 64 patients were enrolled in the study. Mini Mental Test (MMT) scores were obtained on the initial admission day (MMT1), 24 hours prior to the surgery (MMT2) and 24 hours after the surgery (MMT3). The patients were divided into two groups according to the MMT scores: 'no cognitive dysfunction' (group 1) and 'cognitive dysfunction' (group 2). Differences between the groups were evaluated statistically. The statistical significance level was set as P < .05 in a 95% confidence interval.

RESULTS

The POCD incidence rate was calculated as 43.8% in all patients. The preoperative hospitalisation duration was significantly longer in patients with POCD than in patients without POCD (P < .001). The factors that affected POCD development were found to be advanced age (P < .001), high American Society of Anesthesiologists scores (P = .004), the presence of comorbid disease (P = .025), durations of surgery (P = .018) and decreased postoperative haematocrit levels (P = .014).

CONCLUSION

In this study, we observed that patients with early POCD had relatively longer preoperative hospitalisation periods than those in patients without POCD. We consider that prolonged preoperative hospitalisation may contribute to increased POCD incidence rates in patients with risk factors.

Bone Fracture Enhanced Blood-Brain Barrier Breakdown in the Hippocampus and White Matter Damage of Stroke Mice

Background: Tibia fracture (BF) before stroke shortly causes long-term post-stroke memory dysfunction in mice. The mechanism is unclear. We hypothesize that BF enhances neuroinflammation and blood brain barrier (BBB) breakdown in the hippocampus and white matter (WM) damage. Methods: Mice were assigned to groups: BF, stroke, BF+stroke (BF 6 h before stroke) and sham. BBB integrity was analyzed 3 days after the surgeries and WM injury was analyzed 3 days and 8 weeks after the surgeries. Results: Stroke and BF+stroke groups had more activated microglia/macrophages and lower levels of claudin-5 in the ipsilateral hippocampi than the BF group. BF+stroke group had the highest number microglia/macrophages and the lowest level of claudin-5 among all groups and had fewer pericytes than BF group. Stroke and BF+stroke groups had smaller WM areas in the ipsilateral basal ganglia than the sham group 8 weeks after the injuries. The BF+stroke group also had smaller WM areas in the ipsilateral than sham and BF groups 3 days after the injuries and in the contralateral basal ganglia than stroke and BF groups 8 weeks after the injuries. Conclusions: BF exacerbates neuroinflammation and BBB leakage in the hippocampus and WM damage in basal ganglia, which could contribute to the long-lasting memory dysfunction in BF+stroke mice.

Effect of Perioperative Active Body Surface Warming Systems on Analgesic and Clinical Outcomes: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

Inadvertent perioperative hypothermia is a common complication of surgery, and active body surface warming (ABSW) systems are used to prevent adverse clinical outcomes. Prior data on certain outcomes are equivocal (ie, blood loss) or limited (ie, pain and opioid consumption). The objective of this study was to provide an updated review on the effect of ABSW on clinical outcomes and temperature maintenance.

METHODS

We conducted a systematic review of randomized controlled trials evaluating ABSW systems compared to nonactive warming controls in noncardiac surgeries. Outcomes studied included postoperative pain scores and opioid consumption (primary outcomes) and other perioperative clinical variables such as temperature changes, blood loss, and wound infection (secondary outcomes). We searched Ovid MEDLINE daily, Ovid MEDLINE, EMBASE, CINHAL, Cochrane CENTRAL, and Web of Science from inception to June 2019. Quality of evidence (QoE) was rated according to the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. Subgroup analysis sought to determine the effect of preoperative + intraoperative warming versus intraoperative warming alone. Metaregression evaluated the effect of year of publication, use of neuromuscular blockers, anesthesia, and surgery type on outcomes.

RESULTS

Fifty-four articles (3976 patients) were included. Pooled results demonstrated that ABSW maintained normothermia compared to controls, during surgery (30 minutes postinduction [mean difference {MD}: 0.3°C, 95% confidence interval {CI}, 0.2-0.4, moderate QoE]), end of surgery (MD: 1.1°C, 95% CI, 0.9-1.3, high QoE), and up to 4 hours postoperatively (MD: 0.3°C, 95% CI, 0.2-0.5, high QoE). ABSW was not associated with difference in pain scores (<24 hours postoperatively, moderate to low QoE) or perioperative opioid consumption (very low QoE). ABSW increased patient satisfaction (MD: 2.2 points, 95% CI, 0.9-3.6, moderate QoE), reduced blood transfusions (odds ratio [OR] = 0.6, 95% CI, 0.4-1.0, moderate QoE), shivering (OR = 0.2, 95% CI, 0.1-0.4, high QoE), and wound infections (OR = 0.3, 95% CI, 0.2-0.7, high QoE). No significant differences were found for fluid administration (low QoE), blood loss (very low QoE), major adverse cardiovascular events (very low QoE), or mortality (very low QoE). Subgroup analysis and metaregression suggested increased temperature benefit with pre + intraoperative warming, use of neuromuscular blockers, and recent publication year. ABSW seemed to confer less temperature benefit in cesarean deliveries and neurosurgical/spinal cases compared to abdominal surgeries.

CONCLUSIONS

ABSW is effective in maintaining physiological normothermia, decreasing wound infections, shivering, blood transfusions, and increasing patient satisfaction but does not appear to affect postoperative pain and opioid use.

The Relationship of Postoperative Delirium and Unplanned Perioperative Hypothermia in Surgical Patients

PURPOSE

The purpose of this study was to investigate associations between postoperative delirium (POD) and unplanned perioperative hypothermia (UPH) among adults undergoing noncardiac surgery.

DESIGN

A retrospective, exploratory design was used.

METHODS

A retrospective, exploratory study was conducted using electronic medical record data abstracted from a purposive convenience sample of adult patients undergoing noncardiac surgery from January 2014 to June 2017.

FINDINGS

The analyzed data set included 22,548 surgeries, of which 9% experienced POD. Logistic regression indicated that American Society of Anesthesiologists (ASA) class was the strongest predictor of POD (χ² = 1,207.11, df = 4, inclusive of all ASA class terms). A significant relationship between UPH and POD (χ² = 54.94, df = 4, inclusive of all UPH terms) and a complex relationship among UPH, patient age, ASA class, and POD were also found.

CONCLUSIONS

Results support a relationship between UPH and POD. Notably, there is also a complex relationship in the noncardiac surgery population among UPH, age, ASA class, and POD. Preliminary understanding of this relationship is based on the pathophysiological response to surgical stress. Further research is indicated.

Fracture shortly before stroke in mice leads to hippocampus inflammation and long-lasting memory dysfunction

Cognitive impairment occurs in stroke and hip fracture patients. In mice, bone fracture (BF) exacerbates stroke-related neuronal damage and sensorimotor dysfunction. We hypothesize that BF exacerbates post-stroke cognitive impairment. Adult mice were randomly assigned into BF, stroke, BF+stroke (BF 6 h before stroke), and control (sham operated) groups. Memory function was evaluated weekly for eight weeks by Y maze test and at eight weeks post-surgeries by novel object recognition (NOR) test. The neuronal damage and inflammation in hippocampus were analyzed three days and eight weeks after the surgeries. In Y maze test, BF+stroke mice started making fewer alternations than controls two weeks after the surgeries. Significant difference between BF+stroke and stroke groups started at five weeks post-injury and continued to the end of the experiment. In NOR test, BF+stroke group spent less time on novel objective than that of other groups. Cx3cr1⁺ cells and CD68⁺ cells accumulated in the stratum lacunosum moleculare (SLM) on the ipsilateral side of stroke injury in stroke and BF+stroke mice. BF+stroke mice had a higher ratio of ipsilateral/contralateral Cx3cr1⁺ cell-density than that of stroke mice. Therefore, BF shortly before stroke exacerbates hippocampal inflammation and causes long-lasting memory dysfunction.

Comparative effects of fentanyl versus sufentanil on cerebral oxygen saturation and postoperative cognitive function in elderly patients undergoing open surgery

This study was aimed to systematically evaluate the effects of fentanyl and sufentanil on intraoperative cerebral oxygen saturation changes and postoperative cognitive function in elderly patients undergoing open surgery. Ninety-six elderly patients who had undergone open surgery under general anesthesia were randomly divided into fentanyl group (F group, anesthesia by fentanyl, 4 g/kg) and sufentanil group (S group, anesthesia by sufentanil, 0.4 µg/kg). There were no significant differences between the F group and S group in the general characteristics of patients. Compared to the F group, the S group had a better effect on suppressing the stress response, maintaining a stable hemodynamic status and achieving better anesthesia effects. The anesthesia recovery time of the S group was significantly shorter than that of the F group. There was no significant difference between the two groups in the intraoperative and postoperative agitation. Patient's waking time and extubation time were significantly shorter in the S group than the F group. The VAS scores in the S group were significantly lower than those in the F group at each time point. The Ramsay scores in the S group were significantly higher than those in the F group at each time point. The cerebral oxygen saturation (SctO₂) levels in both groups were significantly increased following anesthesia induction and intubation compared to that of the awake state (P < 0.05), and SctO₂ was significantly decreased during the surgery in both groups. The changes in SctO₂ levels were not significantly different between the two groups (P > 0.05). The SctO₂ level was significantly higher during surgery than that after intubation. Compared with the F group, the relative value of SctO₂ decline in the S group was smaller. Compared to the day before surgery, the Montreal Cognitive Assessment (MoCA) scores of both groups were significantly reduced after surgery. At 1 day post-surgery, the MoCA scores of the S group were significantly higher and the incidence of postoperative cognitive dysfunction (POCD) was significantly lower compared to the F group. POCD occurred in three patients (6.2%) in the S group, and the ratio was significantly lower than that in the F group (11.9%) (P < 0.05). It showed a consistent trend with the SctO₂ status during the surgery. The relative value of SctO₂ decline in the S group was significantly smaller than that in the F group. The reduction of cognitive function in the S group was significantly lower than that in the F group. These results indicate that the changes in SctO₂ are a good prediction of the incidence of POCD.

Histone H3K9 Trimethylation Downregulates the Expression of Brain-Derived Neurotrophic Factor in the Dorsal Hippocampus and Impairs Memory Formation During Anaesthesia and Surgery

Brain-derived neurotrophic factor (BDNF) is essential for cognitive and memory functions. Abnormal BDNF expression in the central nervous system may impair these functions. Anaesthesia and surgery can induce perioperative neurocognitive disorders (PND). Clinical studies show that BDNF expression is decreased in patients presenting with cognitive impairment after anaesthesia and surgery. However, the molecular mechanism is still unclear. Epigenetic regulation plays an important role in cognition. The hypermethylation of H3K9 is crucial for transcriptional silencing and the onset of cognitive disorders. Here, we hypothesised that H3K9 trimethylation repressed BDNF expression and impaired memory formation or recall during anaesthesia and surgery. Laparotomy under isoflurane inhalation anaesthesia, behavioural tests, Western blotting, quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR), chromatin immunoprecipitation (ChIP), and immunohistochemistry were used in this study. BDNF expression was decreased in the hippocampus after anaesthesia and surgery. Cognitive impairment affected memory formation but not recall. The trimethylation of H3K9 downregulated BDNF expression. The overexpression of BDNF or use of exogenous BDNF improved the impairment of memory formation caused by anaesthesia and surgery. Therefore, inhibiting H3K9 trimethylation and increasing the expression of BDNF may help prevent PND in the clinical setting.

Brain metastases and treatment: multiplying cognitive toxicities

INTRODUCTION

Thirty per cent of cancer patients develop brain metastases, with multiple combination or sequential treatment modalities available, to treat systemic or central nervous system (CNS) disease. Most patients experience toxicities as a result of these treatments, of which cognitive impairment is one of the adverse events most commonly reported, causing major impairment of the patient's quality of life. Areas covered: This article reviews the role of cancer treatments in cognitive decline of patients with brain metastases: surgery, radiotherapy, chemotherapy, targeted therapies, immunotherapies and hormone therapy. Pathological and molecular mechanisms, as well as future directions for limiting cognitive toxicities are also presented. Other causes of cognitive impairment in this population are discussed in order to refine the benefit-risk balance of each treatment modality. Expert opinion: Cumulative cognitive toxicity should be taken into account, and tailored to the patient's cognitive risk in the light of the expected survival benefit. Standardization of cognitive assessment in this context is needed in order to better appreciate each treatment's responsibility in cognitive impairment, keeping in mind disease itself impacts cognition in this context.

[Research status of the enhanced recovery after surgery in the geriatric hip fractures]

Objective

To summarize the latest developments in the enhanced recovery after surgery (ERAS) in the geriatric hip fractures and its perioperative therapy management.

Methods

The recent original literature on the ERAS in the geriatric hip fractures were extensively reviewed, illustrating the concepts and properties of the ERAS in the geriatric hip fractures.

Results

It has been considered to be associated with the decreased postoperative morbidity, reduced hospital length of stay, and cost savings to implement ERAS protocols, including multimodal analgesia, inflammation control, intravenous fluid therapy, early mobilization, psychological counseling, and so on, in the perioperative (emergency, preoperative, intraoperative, postoperative) management of the geriatric hip fractures. The application of ERAS in the geriatric hip fractures guarantees the health benefits of patients and saves medical expenses, which also provides basis and guidance for the further development and improvement of the entire process perioperative management in the geriatric hip fractures.

Conclusion

Significant progress has been made in the application of ERAS in the geriatric hip fractures. ERAS protocols should be a priority for perioperative therapy management in the geriatric hip fractures.

Enhanced recovery after surgery for primary hip and knee arthroplasty: a review of the evidence

Enhanced recovery after surgery (ERAS) protocols produce significant clinical and economic benefits in a range of surgical subspecialties. There is a long tradition of applying clinical pathways to the perioperative care of joint arthroplasty patients. Enhanced recovery after surgery represents the next step in the evolution of standardized care. To date, reports of full ERAS pathways for hip or knee arthroplasty are lacking. In this narrative review, we present the evidence base that can be usefully applied to constructing ERAS pathways for hip or knee arthroplasty. The history and rationale for applying ERAS to joint arthroplasty are explained. Evidence demonstrates improved outcomes after joint arthroplasty when a standardized approach to care is implemented. The efficacy of individual ERAS components in hip or knee replacement is considered, including preoperative education, intraoperative anaesthetic techniques, postoperative analgesia, and early mobilization after joint arthroplasty. Interventions lacking high-quality evidence are identified, together with recommendations for future research. Based on currently available evidence, we present a model ERAS pathway that can be applied to perioperative care of patients undergoing hip or knee arthroplasty.

Impact of Bone Fracture on Ischemic Stroke Recovery

Stroke is one of the most devastating complications of bone fracture, occurring in up to 4% of patients after surgical repair for hip fracture. Bone fracture and ischemic stroke have many common risk factors. The impact of bone fracture on stroke recovery has not drawn much attention in the research field. Bone fracture could occur in stroke patients at different times during the recovery phase, which steepens the trajectory of cognitive decline, greatly affects the quality of life, and causes a heavy burden on healthcare resources. In this paper, we reviewed the growing information on the pathophysiological mechanisms by which bone fracture may affect ischemic stroke recovery process.

Warming infusion improves perioperative outcomes of elderly patients who underwent bilateral hip replacement

BACKGROUND

This prospective, randomized, and controlled study was performed to determine the benefits of prewarmed infusion in elderly patients who underwent bilateral hip replacement.

METHODS

Between September 2015 and April 2016, elderly patients who underwent bilateral hips replacement that met the inclusion and exclusion criteria were included in this study. After inclusion, patients were randomized into one of the study groups: in the control group, patients received an infusion of fluid kept at room temperature (22-23°C); in the warming infusion group, patients received an infusion of fluid warmed using an infusion fluid heating apparatus (35°C). Postoperative outcomes, including recovery time, length of hospital stay, visual analogue scale (VAS) score, and postoperative complications rate of patients from both groups, were compared.

RESULTS

A total of 64 patients were included in our study (71.2 ± 7.6 years, 53.1% males), with 32 patients in the control group and 32 patients in warming infusion group. No significant difference was found in terms of demographic data and intraoperative blood transfusion rate between 2 groups (P > 0.05). Patients receiving a prewarmed infusion had a significantly shorter time to spontaneous breath, eye opening, consciousness recovery, and extubation than the control group (P < 0.05). In addition, significant differences were found in Steward score and VAS score between 2 groups (P < 0.05). Moreover, warming infusion group also showed an obviously decreased incidence of shivering and postoperative cognitive dysfunction (P < 0.05).

CONCLUSION

A prewarmed infusion could reduce the incidence of perioperative hypothermia and improve outcomes in the elderly during bilateral hip replacement.

Effectiveness of active and passive warming for the prevention of inadvertent hypothermia in patients receiving neuraxial anesthesia: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

Perioperative hypothermia is a common complication of anesthesia that can result in negative outcomes. The purpose of this review is to answer the question: Does the type of warming intervention influence the frequency or severity of inadvertent perioperative hypothermia (IPH) in surgical patients receiving neuraxial anesthesia?

DESIGN

Systematic review and meta-analysis.

SETTING

Perioperative care areas.

PATIENTS

Adults undergoing surgery with neuraxial anesthesia.

INTERVENTION

Perioperative active warming (AW) or passive warming (PW).

MEASUREMENTS

PubMed, CINAHL, Embase, and Cochrane Central Register of Controlled Trials were searched. Inclusion criteria were: randomized controlled trials; adults undergoing surgery with neuraxial anesthesia; comparison(s) of AW and PW; and temperature measured at end of surgery/upon arrival in the Postanesthesia Care Unit. Exclusion criteria were: no full-text available; not published in English; studies of: combined neuraxial and general anesthesia, warm intravenous or irrigation fluids without using AW, and rewarming after hypothermia. Two independent reviewers screened abstracts and titles, and selected records following full-text review. The Cochrane Collaboration's tool for assessing risk of bias was used to evaluate study quality. A random-effects model was used to calculate risk ratios for dichotomous data and mean differences for continuous data.

MAIN RESULTS

Of 1587 records, 25 studies (2048 patients) were included in the qualitative synthesis. Eleven studies (1189 patients) comparing AW versus PW were included in the quantitative analysis. Meta-analysis found that intraoperative AW is more effective than PW in reducing the incidence of IPH during neuraxial anesthesia (RR=0.71; 95% CI 0.61-0.83; p<0.0001; I²=32%). The qualitative synthesis revealed that IPH continues despite current AW technologies.

CONCLUSIONS

During neuraxial anesthesia, AW reduces IPH more effectively than PW. Even with AW, IPH persists in some patients. Continued innovation in AW technology and additional comparative effectiveness research studying different AW methods are needed.

Depression and anxiety after total joint replacement among older adults: a meta-analysis

OBJECTIVE

Patients usually experience good physical recovery after total joint replacement (TJR); however, it is unclear whether mood also improves. The current meta-analysis examined changes in depression and anxiety following TJR in older (≥50 years) patients in order to address this gap in the literature.

METHODS

Data from 26 studies (4045 TJR, 55 controls) that assessed depression and/or anxiety pre- and post-surgery in TJR patients, with or without a control group, were analyzed. Prevalence rates and Cohen's d effect sizes were used to evaluate changes in the prevalence and severity of depression/anxiety, respectively.

RESULTS

Approximately 23% of TJR patients had clinically significant levels of depression prior to surgery, which decreased to 13% one year later. The prevalence of anxiety could not be evaluated due to the limited available data. TJR patients did not show any clinically meaningful reductions in symptoms of depression or anxiety, following surgery. Compared to controls, there was no difference in symptom progression over time; although only one study examined this.

CONCLUSIONS

TJR patients appear to have higher rates of clinically significant symptoms of depression before and after surgery, compared to the general population, however more research with adequate control groups is needed to confirm this. Only a modest improvement in the severity of depression and anxiety symptoms was noted post-surgery. However, existing research is limited; preventing definite conclusions regarding the impact of TJR on mood.

Post-operative cognitive dysfunction at 3 months in adults after non-cardiac surgery: a qualitative systematic review

BACKGROUND

Post-operative cognitive dysfunction is defined as a decline in cognitive functions that occurs after surgery, but different diagnostic criteria and incidences have been reported in medical literature. Our aim was to determine incidence of post-operative cognitive dysfunction 3 months after non-cardiac surgery in adults.

METHODS

A systematic review of available evidence was performed by PRISMA guidelines. A search was done in May-July 2015 on PubMed, EMBASE, CINAHL, LILACS, Scielo, Clinical Trials, and Grey Literature Reports. Inclusion criteria were prospective design studies with patients over 18 years old, surgery under general or regional anesthesia, follow-up for 3 months, and use of a neurocognitive battery for diagnosis. We excluded studies made on cardiac or brain surgery patients. Risk of bias was assessed using tools from National Heart Lung and Blood Institute.

RESULTS

We selected 24 studies. Average age was 68 years. Only five studies reported incidence of cognitive decline for a non-surgical control group. Median number of tests used was 5 (range 3-13). Pooled incidence of post-operative cognitive dysfunction at 3 months was 11.7% [95% CI 10.9-12.5] but with several methodological differences between studies. Increasing age was the most consistent risk factor identified (seven studies).

CONCLUSIONS

Post-operative cognitive dysfunction in patients is frequent, especially in patients over 60 years old. Limitations include methodological differences in studies. Efforts must be made to reach a consensus in definition and diagnosis for future research.

Active body surface warming systems for preventing complications caused by inadvertent perioperative hypothermia in adults

BACKGROUND

Inadvertent perioperative hypothermia is a phenomenon that can occur as a result of the suppression of the central mechanisms of temperature regulation due to anaesthesia, and of prolonged exposure of large surfaces of skin to cold temperatures in operating rooms. Inadvertent perioperative hypothermia has been associated with clinical complications such as surgical site infection and wound-healing delay, increased bleeding or cardiovascular events. One of the most frequently used techniques to prevent inadvertent perioperative hypothermia is active body surface warming systems (ABSW), which generate heat mechanically (heating of air, water or gels) that is transferred to the patient via skin contact.

OBJECTIVES

To assess the effectiveness of pre- or intraoperative active body surface warming systems (ABSW), or both, to prevent perioperative complications from unintended hypothermia during surgery in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; Issue 9, 2015); MEDLINE (PubMed) (1964 to October 2015), EMBASE (Ovid) (1980 to October 2015), and CINAHL (Ovid) (1982 to October 2015).

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared an ABSW system aimed at maintaining normothermia perioperatively against a control or against any other ABSW system. Eligible studies also had to include relevant clinical outcomes other than measuring temperature alone.

DATA COLLECTION AND ANALYSIS

Several authors, by pairs, screened references and determined eligibility, extracted data, and assessed risks of bias. We resolved disagreements by discussion and consensus, with the collaboration of a third author.

MAIN RESULTS

We included 67 trials with 5438 participants that comprised 79 comparisons. Forty-five RCTs compared ABSW versus control, whereas 18 compared two different types of ABSW, and 10 compared two different techniques to administer the same type of ABSW. Forced-air warming (FAW) was by far the most studied intervention.Trials varied widely regarding whether the interventions were applied alone or in combination with other active (based on a different mechanism of heat transfer) and/or passive methods of maintaining normothermia. The type of participants and surgical interventions, as well as anaesthesia management, co-interventions and the timing of outcome measurement, also varied widely. The risk of bias of included studies was largely unclear due to limitations in the reports. Most studies were open-label, due to the nature of the intervention and the fact that temperature was usually the principal outcome. Nevertheless, given that outcome measurement could have been conducted in a blinded manner, we rated the risk of detection and performance bias as high.The comparison of ABSW versus control showed a reduction in the rate of surgical site infection (risk ratio (RR) 0.36, 95% confidence interval (CI) 0.20 to 0.66; 3 RCTs, 589 participants, low-quality evidence). Only one study at low risk of bias observed a beneficial effect with forced-air warming on major cardiovascular complications (RR 0.22, 95% CI 0.05 to 1.00; 1 RCT with 12 events, 300 participants, low-quality evidence) in people at high cardiovascular risk. We found no beneficial effect for mortality. ABSW also reduced blood loss during surgery but the magnitude of this effect seems to be irrelevant (MD -46.17 mL, 95% CI -82.74 to -9.59; I² = 78%; 20 studies, 1372 participants). The same conclusion applies to total fluids infused during surgery (MD -144.49 mL, 95% CI -221.57 to -67.40; I² = 73%; 24 studies, 1491 participants). These effects did not translate into a significant reduction in the number of participants being transfused or the average amount of blood transfused. ABSW was associated with a reduction in shivering (RR 0.39, 95% CI 0.28 to 0.54; 29 studies, 1922 participants) and in thermal comfort (standardized mean difference (SMD) 0.76, 95% CI 0.29 to 1.24; I² = 77%, 4 trials, 364 participants).For the comparison between different types of ABSW system or modes of administration of a particular type of ABSW, we found no evidence for the superiority of any system in terms of clinical outcomes, except for extending systemic warming to the preoperative period in participants undergoing major abdominal surgery (one study at low risk of bias).There were limited data on adverse effects (the most relevant being thermal burns). While some trials included a narrative report mentioning that no adverse effects were observed, the majority made no reference to it. Nothing so far suggests that ABSW involves a significant risk to patients.

AUTHORS' CONCLUSIONS

Forced-air warming seems to have a beneficial effect in terms of a lower rate of surgical site infection and complications, at least in those undergoing abdominal surgery, compared to not applying any active warming system. It also has a beneficial effect on major cardiovascular complications in people with substantial cardiovascular disease, although the evidence is limited to one study. It also improves patient's comfort, although we found high heterogeneity among trials. While the effect on blood loss is statistically significant, this difference does not translate to a significant reduction in transfusions. Again, we noted high heterogeneity among trials for this outcome. The clinical relevance of blood loss reduction is therefore questionable. The evidence for other types of ABSW is scant, although there is some evidence of a beneficial effect in the same direction on chills/shivering with electric or resistive-based heating systems. Some evidence suggests that extending systemic warming to the preoperative period could be more beneficial than limiting it only to during surgery. Nothing suggests that ABSW systems pose a significant risk to patients.The difficulty in observing a clinically-relevant beneficial effect with ABSW in outcomes other than temperature may be explained by the fact that many studies applied concomitant procedures that are routinely in place as co-interventions to prevent hypothermia, whether passive or active warming systems based in other physiological mechanisms (e.g. irrigation fluid or gas warming), as well as a stricter control of temperature in the context of the study compared with usual practice. These may have had a beneficial effect on the participants in the control group, leading to an underestimation of the net benefit of ABSW.

Cerebral oxygen saturation after multiple perioperative influential factors predicts the occurrence of postoperative cognitive dysfunction

Background

Postoperative cognitive dysfunction (POCD) is a frequent complication in elderly patients undergoing major non-cardiac surgery, but its etiology is still unclear. Cerebral oxygen saturation (ScO₂) represents the balance of cerebral oxygen supply and demand. The aim of present study was to evaluate the relationship between perioperative ScO₂ and POCD, and to verify the hypothesis that the value of ScO₂ after multiple perioperative influential factors could predict POCD in elderly patients undergoing total knee arthroplasty (TKA).

Methods

Seventy eight Patients aged more than 65 years undergoing elective TKA with intrathecal anesthesia were enrolled. Cognitive functions were assessed one day before and 6 days after surgery, and POCD were defined according to ISPOCD. Demographics were recorded. Perioperative ScO₂, blood pressure (BP), blood gas analysis and other clinical data were monitored and recorded, then the decrease of ScO₂, BP and PaO₂ after influential factors were calculated.

Results

POCD occurred in 15 patients (19.2 %). BP decreased after anesthesia induction and tourniquet deflation, and PaO₂ decreased after cement implantation, then percentage decrease of BP was higher in POCD group. ScO₂ of POCD group is significantly lower than non-POCD group (P < 0.05), and the absolute value and percentage decrease of ScO₂ became significant between two groups after multiple influential factors. ScO₂ after all influential factors (anesthesia induction, cement implantation and tourniquet deflation) had the best predictive performance for POCD (AUC = 0.742), and the optimal threshold was 66.5 %.

Conclusions

Perioperative ScO₂ of patients with POCD is lower than patients without POCD. ScO₂ after multiple perioperative influential factors could be an effective predictor for POCD, which reveal an important role of ScO₂ decrease in the development of POCD and provide possible treatment target.

The effect of intraoperative sounds of saw and hammer on psychological condition in patients with total knee arthroplasty: prospective randomized study

Purpose. Surgical procedures are likely to be stressful for patients and their families. Total knee arthroplasty (TKA) is a major surgical procedure used in the treatment of osteoarthritis. During this procedure the sounds of the saw and hammer may irritate the patient and adversely affect mood. The present study examines the effect of these intraoperative sounds during TKA on postoperative mood and anxiety, by comparing two different anesthetic procedures. Methods. A total of 40 patients who underwent TKA for grade IV gonarthrosis participated in the study. Patients were randomly divided into two groups: 20 patients in the general anesthesia group and 20 patients in the spinal anesthesia group. Mood and anxiety changes were evaluated using the Profile of Mood States (POMS) and State-Trait Anxiety Inventory (STAI) instruments, respectively. Results. The postoperative POMS value in the spinal anesthesia group was definitively higher than the general anesthesia group, though the difference in preoperative and postoperative POMS and STAI scores between the two groups was not significant. Conclusion. It would seem that sounds of hammer and saw have no evident negative effect on patient's mood. Regional anesthesia is advisable for TKA patients and appropriate sedation can be administered during the operation if needed.

Plasma levels of tumor necrosis factor-α in adolescent idiopathic scoliosis patients serve as a predictor for the incidence of early postoperative cognitive dysfunction following orthopedic surgery

The aim of the present study was to evaluate whether the levels of the plasma biomarkers, cortisol, interleukin (IL)-1β, IL-6, IL-10 and tumor necrosis factor (TNF)-α, change in adolescent idiopathic scoliosis patients with postoperative cognitive dysfunction (POCD); thus, may serve as predictive factors for POCD. In total, 75 adolescent scoliosis patients, aged between 11 and 18 years and categorized as American Society of Anesthesiologists classification I or II, were scheduled for orthopedic surgery with general anesthesia. Blood samples were collected on the day of admission and at day 2 following surgery. The plasma levels of IL-1β, IL-6, IL-10 and TNF-α were measured using an enzyme-linked immunosorbent assay, while the concentrations of cortisol were determined using a radioimmunoassay. Cognitive function was assessed one day prior to and at day 7 following the surgery in a quiet room with the guidance of a Chinese version protocol. In total, 66 patients completed the sample collection and neurocognitive tests. According to the criteria for the diagnosis of POCD, 19 patients (28.8%) developed POCD within seven days of surgery. No statistically significant differences were observed in the baseline concentrations of cortisol, TNF-α, IL-1β, IL-10 or IL-6 between the POCD and non-POCD groups. However, the baseline plasma level of TNF-α on day 2 in the POCD group was found to be higher compared with the non-POCD group. In addition, at day 2 after surgery, the concentration of cortisol in the non-POCD group was higher compared with the POCD group. Therefore, the plasma level of TNF-α in adolescent idiopathic scoliosis patients at day 2 following orthopedic surgery may be a predictor for the incidence of early POCD.

Relationship between intraoperative regional cerebral oxygen saturation trends and cognitive decline after total knee replacement: a post-hoc analysis

Background

Bilateral regional brain oxygen saturation (rSO₂) trends, reflecting intraoperative brain oxygen imbalance, could warn of brain dysfunction. Various types of cognitive impairment, such as memory decline, alterations in executive function or subjective complaints, have been described three months after surgery. Our aim was to explore the potential utility of rSO₂ values as a warning sign for the development of different types of decline in postoperative psychological function.

Methods

Observational post-hoc analysis of data for the patient sample (n = 125) of a previously conducted clinical trial in patients over the age of 65 years undergoing total knee replacement under spinal anesthesia. Demographic, hemodynamic and bilateral rSO₂ intraoperative values were recorded. An absolute rSO₂ value of <50% or a reduction of >20% or >25% below baseline were chosen as relevant cutoffs. Composite function test scores were created from baseline to three months for each patient and adjusted for the mean (SD) score changes for a control group (n = 55). Tests were used to assess visual-motor coordination and executive function (VM-EF) (Wechsler Digit Symbol-Coding and Visual Reproduction, Trail Making Test) and memory (Auditory Verbal Learning, Wechsler Memory Scale); scales were used to assess psychological symptoms.

Results

We observed no differences in baseline rSO₂ values; rSO₂ decreased significantly in all patients during surgery (P < 0.0001). Seventy-five patients (60%) had no sign of cognitive decline or psychological symptoms. Twenty-one patients (16.8%) had memory decline, 3 (2.4%) had VM-EF decline, and 33 (26.4%) had psychological symptoms. Left and right rSO₂ values were asymmetric in patients who had memory decline (mean [SD] left-right ratio of 95.03 [8.51] vs 101.29 [6.7] for patients with no changes, P = 0.0012). The mean right-left difference in rSO₂ was also significant in these patients (-2.87% [4.73%], lower on the right, P = 0.0034).

Conclusions

Detection of a trend to asymmetry in rSO₂ values can warn of possible postoperative onset of memory decline. Psychological symptoms and memory decline were common three months after knee replacement in our patients over the age of 65 years.

Impact of warming blood transfusion and infusion toward cerebral oxygen metabolism and cognitive recovery in the perioperative period of elderly knee replacement

Objective

This study aims to observe the impact of the temperature of blood transfusion and infusion toward the perioperative cerebral oxygen metabolism and the postoperative cognitive recovery.

Methods

Eighty patients of knee replacement under epidural and general anesthesia were randomly divided into warming blood transfusion and infusion (WBI) group (n = 40) and control group (n = 40). The changes of nasopharyngeal temperature, middle cerebral artery blood flow, CERO₂, and SjVO₂ of the two groups were recorded at each time point for the assessment of the postoperative overall quality of recovery and cognitive recovery situation.

Results

The nasopharyngeal temperatures of the two groups at different time points after transfusion were significantly lower than that at T1, and there was a significant difference between the two groups (P < 0.05). The CERO₂ values of the two groups at T3 were significantly higher than at T1, while the SjVO₂ values were significantly decreased (P < 0.01).

Conclusion

The WBI can significantly reduce the occurrence of the perioperative hypothermia, while it has no significant effect toward cerebral oxygen metabolism, postoperative overall recovery, and recovery of cognitive function.

Postoperative cognitive dysfunction after total joint arthroplasty in the elderly: a meta-analysis

This meta-analysis consolidated the research on postoperative cognitive dysfunction (POCD) following total joint arthroplasty (TJA). Data from 17 studies that assessed cognition pre- and post-surgery in TJA patients alone (15 studies) or matched TJA and control groups (2 studies) were analysed. Results were grouped by cognitive domain (memory, attention, language, speed, general cognition) and follow-up interval (pre-discharge, 3-6 months post-surgery). The TJA data revealed small declines in reaction time and general cognition pre-discharge, but no evidence of decline 3-6 months post-surgery. Very limited TJA and Control data indicated no group differences in the changes to performance over time; however, the TJA group was cognitively compromised pre- and post-surgery compared to Controls. Further appropriately controlled research is required to clarify whether POCD commonly occurs after TJA.

[Postoperative cognitive dysfunction. Possible neuronal mechanisms and practical consequences for clinical routine]

Postoperative cognitive dysfunction (POCD) presents as a long-lasting decline in cognitive function after a surgical procedure, predominantly occurring in elderly patients. The causes are most likely multifactorial with the exact mechanisms still unknown. Hypotheses of the causes of POCD are based on experimental evidence that anesthetics can impair mechanisms of learning and memory on a neuronal level and might lead to neurodegeneration. Additionally, surgery can result in neuroinflammation which could also underlie POCD. The most important strategy to avoid POCD is to maintain the patient's physiological homeostasis perioperatively. According to the presently available clinical studies recommendations in favor or against certain anesthesiological procedures cannot be given.