Emergence delirium in adults in the post-anaesthesia care unit

Dorsal Penile Nerve Block With Ropivacaine-Reduced Postoperative Catheter-Related Bladder Discomfort in Male Patients After Emergence of General Anesthesia: A Prospective, Randomized, Controlled Study

Catheter-related bladder discomfort (CRBD) is a distressing symptom complex after surgery, especially in male patients who have had urinary catheterization under general anesthesia. In this prospective, randomized, controlled trial, we compared dorsal penile nerve block (DPNB) with 0.33% ropivacaine with intravenous tramadol 1.5 mg kg(-1) in prevention of CRBD, as well as the incidences of postoperative side effects. Fifty-eight male patients aged 18 to 50 years, undergoing elective liver surgery and limb surgery with urinary catheterization, were enrolled and divided randomly into 2 groups. In the DPNB group, patients were given dorsal penile nerve block with 15 mL of 0.33% ropivacaine, and in the tramadol intravenous administration (TRAM) group, patients were given 1.5 mg kg(-1) tramadol after the completion of surgery before extubation. The primary outcome was the incidence of CRBD, and the secondary outcomes included the severity of CRBD, postoperative side effects, postoperative pain, and the acceptance of urinary catheterization. Patients were evaluated upon arrival to postanesthetic care unit (PACU), at 0.5, 1, 2, 4, and 6 hours after patients' arrival in the PACU for outcomes. The incidence of CRBD was significantly lower in the DPNB group than in the TRAM group, either upon arrival to PACU (10.3% vs 37.9%, P = 0.015), or at 0.5 hours (3.4% vs 34.5%, P = 0.003), 1 hours (3.4% vs 37.9%, P = 0.001), 2 hours (6.9% vs 34.5%, P = 0.010), and 4 hours (6.9% vs 27.6%, P = 0.039) after patients' arrival in PACU. Compared with the TRAM group, the severity of postoperative CRBD upon arrival to PACU (P = 0.011) and at 0.5 hours (P = 0.005), 1 hours (P = 0.002), 2 hours (P = 0.005), 4 hours (P = 0.017), and 6 hours (P = 0.047) after patients' arrival in PACU were all significantly reduced in the DPNB group. The incidences of postoperative nausea, vomiting, dizziness, and sedation were decreased significantly in the DPNB group compared with the TRAM group (P < 0.05). The acceptance of urinary catheterization was 93.1% (27/29 patients) in the DPNB group and 58.6% (17/29 patients) in the TRAM group, respectively (P < 0.001).DPNB with ropivacaine has a better effect for CRBD reduction and less side effects than intravenous tramadol administration. The trial has been registered at www.clinicaltrials.gov (NCT01721031).

Enhanced Recovery After Surgery (ERAS) for gastrointestinal surgery, part 2: consensus statement for anaesthesia practice

Background

The present interdisciplinary consensus review proposes clinical considerations and recommendations for anaesthetic practice in patients undergoing gastrointestinal surgery with an Enhanced Recovery after Surgery (ERAS) programme.

Methods

Studies were selected with particular attention being paid to meta‐analyses, randomized controlled trials and large prospective cohort studies. For each item of the perioperative treatment pathway, available English‐language literature was examined and reviewed. The group reached a consensus recommendation after critical appraisal of the literature.

Results

This consensus statement demonstrates that anaesthesiologists control several preoperative, intraoperative and postoperative ERAS elements. Further research is needed to verify the strength of these recommendations.

Conclusions

Based on the evidence available for each element of perioperative care pathways, the Enhanced Recovery After Surgery (ERAS ^®) Society presents a comprehensive consensus review, clinical considerations and recommendations for anaesthesia care in patients undergoing gastrointestinal surgery within an ERAS programme. This unified protocol facilitates involvement of anaesthesiologists in the implementation of the ERAS programmes and allows for comparison between centres and it eventually might facilitate the design of multi‐institutional prospective and adequately powered randomized trials.

Enhanced Recovery After Surgery (ERAS) for gastrointestinal surgery, part 1: pathophysiological considerations

BACKGROUND

The present article has been written to convey concepts of anaesthetic care within the context of an Enhanced Recovery After Surgery (ERAS) programme, thus aligning the practice of anaesthesia with the care delivered by the surgical team before, during and after surgery.

METHODS

The physiological principles supporting the implementation of the ERAS programmes in patients undergoing major abdominal procedures are reviewed using an updated literature search and discussed by a multidisciplinary group composed of anaesthesiologists and surgeons with the aim to improve perioperative care.

RESULTS

The pathophysiology of some key perioperative elements disturbing the homoeostatic mechanisms such as insulin resistance, ileus and pain is here discussed.

CONCLUSIONS

Evidence-based strategies aimed at controlling the disruption of homoeostasis need to be evaluated in the context of ERAS programmes. Anaesthesiologists could, therefore, play a crucial role in facilitating the recovery process.

Effects of dexmedetomidine on smooth emergence from anaesthesia in elderly patients undergoing orthopaedic surgery

BACKGROUND

Intraoperative dexmedetomidine may decrease postoperative emergence agitation in elderly patients due to its sedative effect. In this study, we evaluated the effect of adjuvant dexmedetomidine on smooth emergence from anaesthesia after orthopaedic surgery in elderly patients.

METHODS

A total 115 patients (ASA I-II, aged over 65 years) were randomly allocated into four groups. Anaesthesia was maintained with either sevoflurane or total intravenous anaesthesia (TIVA) comprising propofol and remifentanil. Patients were also administered either dexmedetomidine (0.4 μg kg(-1) hr(-1); SD and TD) intraoperatively or normal saline (SN or TN) as a control. The bispectral index (BIS) score was maintained from 40-60 intraoperatively. All anaesthetics and dexmedetomidine were discontinued at surgical conclusion, and the recovery times (durations to a BIS = 60, 70, and 80; eye opening; and extubation) were measured. The mean arterial pressure, heart rate, Ricker's agitation-sedation scale (RSAS), visual analogue scale (VAS) for pain, and incidences of emergence agitation and postoperative nausea and vomiting (PONV) were measured in the recovery room.

RESULTS

Dexmedetomidine significantly decreased the RSAS score in the SD and TD groups, and a calm state postoperatively occurred more frequently in these groups than in the control groups. The heart rate and incidence of emergence agitation were lower in the dexmedetomidine groups. Recovery time was higher in the SD group than in the SN group, and no significant differences occurred between the TN and TD groups. The VAS score was lower in the SD group than in the SN group, and the PONV did not differ regardless of the use of dexmedetomidine.

CONCLUSIONS

Dexmedetomidine may be an effective intraoperative adjuvant for a reducing emergence agitation and smooth emergence from anaesthesia after orthopaedic surgery in elderly patients.

TRIAL REGISTRATION

Current Controlled Trials NCT01851005 .

Comparison between dexmedetomidine and remifentanil infusion in emergence agitation during recovery after nasal surgery: A randomized double-blind trial

BACKGROUND

Postoperative emergency agitation (EA) is a common problem. Dexmedetomidine and remifentanil may be used to prevent this problem. Our primary aim was to compare dexmedetomidine, remifentanil, and placebo with respect to their effectiveness in preventing postoperative EA.

MATERIAL AND METHODS

Ninety patients undergoing nasal surgery were randomized into three groups. The dexmedetomidine group (group D, n = 30) received dexmedetomidine infusion at a rate of 0.4 μg kg(-1 ) h(-1); the remifentanil group (group R, n = 30) received remifentanil infusion at a rate of 0.05 μg kg(-1) min(-1) from induction of anesthesia until extubation; and the control group (group S, n = 30) received a volume-matched normal saline infusion as a placebo. Propofol (1.5-2 mg kg(-1)) and fentanyl (1 μg kg(-1)) were used to initiate anesthesia, and desflurane was used to maintain anesthesia. The incidence of agitation, hemodynamic parameters, and recovery characteristics were evaluated during emergence.

RESULTS

The incidence of EA was significantly higher in group S (46.7%) compared with groups R and D (3.3 and 20%, respectively; p < 0.001). The lowest incidence of EA was detected in group R (p = 0.046). Residual sedation in the post-anesthesia care unit (PACU) was similar in all groups (p = 0.947). The incidence of nausea or vomiting was significantly lower in group D than in groups R and S (p = 0.043). Administration of analgesics in the PACU was higher in group R than in groups S and D (p = 0.015).

CONCLUSION

Anesthetic maintenance with either remifentanil or dexmedetomidine infusion until extubation provided a more smooth and hemodynamically stable emergence, without complications after nasal surgery. While remifentanil was superior to dexmedetomidine with regard to avoiding EA, dexmedetomidine was more effective than remifentanil regarding vomiting and pain.

Dextroamphetamine (but Not Atomoxetine) Induces Reanimation from General Anesthesia: Implications for the Roles of Dopamine and Norepinephrine in Active Emergence

Methylphenidate induces reanimation (active emergence) from general anesthesia in rodents, and recent evidence suggests that dopaminergic neurotransmission is important in producing this effect. Dextroamphetamine causes the direct release of dopamine and norepinephrine, whereas atomoxetine is a selective reuptake inhibitor for norepinephrine. Like methylphenidate, both drugs are prescribed to treat Attention Deficit Hyperactivity Disorder. In this study, we tested the efficacy of dextroamphetamine and atomoxetine for inducing reanimation from general anesthesia in rats. Emergence from general anesthesia was defined by return of righting. During continuous sevoflurane anesthesia, dextroamphetamine dose-dependently induced behavioral arousal and restored righting, but atomoxetine did not (n = 6 each). When the D1 dopamine receptor antagonist SCH-23390 was administered prior to dextroamphetamine under the same conditions, righting was not restored (n = 6). After a single dose of propofol (8 mg/kg IV), the mean emergence times for rats that received normal saline (vehicle) and dextroamphetamine (1 mg/kg IV) were 641 sec and 404 sec, respectively (n = 8 each). The difference was statistically significant. Although atomoxetine reduced mean emergence time to 566 sec (n = 8), this decrease was not statistically significant. Spectral analysis of electroencephalogram recordings revealed that dextroamphetamine and atomoxetine both induced a shift in peak power from δ (0.1–4 Hz) to θ (4–8 Hz) during continuous sevoflurane general anesthesia, which was not observed when animals were pre-treated with SCH-23390. In summary, dextroamphetamine induces reanimation from general anesthesia in rodents, but atomoxetine does not induce an arousal response under the same experimental conditions. This supports the hypothesis that dopaminergic stimulation during general anesthesia produces a robust behavioral arousal response. In contrast, selective noradrenergic stimulation causes significant neurophysiological changes, but does not promote behavioral arousal during general anesthesia. We hypothesize that dextroamphetamine is more likely than atomoxetine to be clinically useful for restoring consciousness in anesthetized patients, mainly due to its stimulation of dopaminergic neurotransmission.

Emergence agitation during recovery from intracranial surgery under general anaesthesia: a protocol and statistical analysis plan for a prospective multicentre cohort study

INTRODUCTION

Emergence agitation after intracranial surgery is an important clinical issue during anaesthesia recovery. The aim of this multicentre cohort study is to investigate the incidence of emergence agitation, identify the risk factors and determine clinical outcomes in adult patients after intracranial surgery under general anaesthesia. Additionally, we will deliberately clarify the relationship between postoperative pneumocephalus and agitation.

METHODS AND ANALYSIS

The present study is a prospective multicentre cohort study. Five intensive care units (ICUs) in China will participate in the study. Consecutive adult patients admitted to the ICUs after intracranial surgery will be enrolled. Sedation-Agitation Scale (SAS) or Richmond Agitation-Sedation Scale (RASS) will be used to evaluate the patients 12 h after the enrolment. Agitation is defined as an SAS score of 5-7, or an RASS score of +2 to +4. According to the maximal SAS and RASS score, patients will be divided into two cohorts: the agitation group and the non-agitation group. Factors potentially related to emergence agitation will be collected at study entry, during anaesthesia and operation, during postoperative care. Univariate analyses between the agitation and the non-agitation groups will be performed. The stepwise backward logistic regression will be carried out to identify the independent predictors of agitation. Patients will be followed up for 72 h after the operation. Accidental self-extubation of the endotracheal tube and removal of other catheters will be documented. The use of sedatives and analgesics will be collected.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from each of five participating hospitals. Study findings will be disseminated through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

NCT02318199.

Neurocognitive dysfunction risk alleviation with the use of dexmedetomidine in perioperative conditions or as ICU sedation: a meta-analysis

Many studies have reported the beneficial effects of dexmedetomidine on postoperative neurocognitive function but overall evidence is not as clear. We examined this conundrum by meta-analyzing studies that used dexmedetomidine in perioperative conditions or as intensive care unit (ICU) sedation and utilized reliable neurocognitive assessment tests. The literature search was undertaken across several electronic databases including EBSCO, Embase, Google Scholar, Ovid SP, PubMed, Scopus, and Web of Science. Literature search was carried out across several electronic databases and relevant studies were selected after following précised inclusion criteria. Meta-analysis of risk differences (RDs) was carried out and subgroup analyses were performed. Twenty studies were selected from which data of 2612 individuals were used. Initial dexmedetomidine dose was 0.68 ± 0.27 and maintenance dose was 0.54 ± 0.32 in the trials. Dexmedetomidine treatment was associated with significantly lower risk of postoperative/postanesthesia neurocognitive dysfunction both in comparison with saline-treated controls (RD [95% confidence interval, CI]: -0.17 (-0.30, -0.04); P = 0.008) and comparators (-0.16 [-0.28, -0.04]; P = 0.009). In the subgroups analyses, however, there was no significant differences between dexmedetomidine and controls/comparators when studies with confusion assessment method for ICU only (RD: -0.10 (-0.22, 0.02); P = 0.1) or midazolam as comparator only (RD: -0.26 (-0.60, 0.07); P = 0.12) were meta-analyzed. Dexmedetomidine use in the perioperative conditions or as ICU sedation is associated with lower risk of neurocognitive dysfunction. There can be some impact of neurocognitive assessment method, drug interactions, and clinical heterogeneity on the overall outcomes of this meta-analysis.

Identifying pediatric emergence delirium by using the PAED Scale: a quality improvement project

Pediatric emergence delirium is a postoperative phenomenon characterized by aberrant cognitive and psychomotor behavior, which can place the patient and health care personnel at risk for injury. A common tool for identifying emergence delirium is the Level of Consciousness-Richmond Agitation and Sedation Scale (LOC-RASS), although it has not been validated for use in the pediatric population. The Pediatric Anesthesia Emergence Delirium Scale (PAED) is a newly validated tool to measure emergence delirium in children. We chose to implement and evaluate the effectiveness and fidelity of using the PAED Scale to identify pediatric emergence delirium in one eight-bed postanesthesia care unit in comparison with the traditional LOC-RASS. The overall incidence of pediatric emergence delirium found by using the LOC-RASS with a retrospective chart review (3%) was significantly lower than the incidence found by using the LOC-RASS (7.5%) and PAED Scale (11.5%) during the implementation period. Our findings suggest that the PAED Scale may be a more sensitive measure of pediatric emergence delirium, and, in the future, we recommend that health care personnel at our facility use the PAED Scale rather than the LOC-RASS.

Risk factors of emergence agitation in adults undergoing general anesthesia for nasal surgery

Objectives

To identify the incidence and the risk factors of emergence agitation in adults undergoing general anesthesia for nasal surgery.

Methods

We retrospectively examined 792 patients aged ≥18 years who underwent general anesthesia for elective nasal surgery between July 2012 and August 2013. Patients in the postanesthesia care unit with a Richmond Agitation Sedation Scale≥+1 at any time were considered to have emergence agitation.

Results

The overall incidence of emergence agitation is 22.2%. From multivariate regression analysis, the following six variables were found to be significantly associated with emergence agitation (P<0.05): younger age, recent smoking, sevoflurane anesthesia, postoperative pain on the numerical rating scale (NRS)≥5, presence of a tracheal tube, and presence of a urinary catheter. Presence of a tracheal tube was the greatest risk factor, increasing the risk of developing emergence agitation by approximately fivefold (odds ratio, 5.448; 95% confidence interval, 2.973 to 9.982). Younger age was also a strong risk factor (odds ratio, 0.975 for each 1-year increase; 95% confidence interval, 0.964 to 0.987). Current smoking, sevoflurane anesthesia, postoperative pain of NRS≥5, and the presence of a urinary catheter nearly doubled the risk of emergence agitation.

Conclusion

Emergence agitation following general anesthesia is a common complication in adult nasal surgery patients. To reduce the occurrence and consequences of agitation episodes, elimination of the associated risk factors is necessary, especially in at-risk patients.

Emergence agitation after orthognathic surgery: a randomised controlled comparison between sevoflurane and desflurane

BACKGROUND

This study aimed to compare emergence agitation following sevoflurane and desflurane anaesthesia in adults undergoing orthognathic surgery. The hypothesis was that there might be a difference in the incidence of emergence agitation following sevoflurane and desflurane anaesthesia considering the difference in blood solubility and speed of recovery between the two.

METHODS

In this prospective randomised double-blind study, 144 adults undergoing orthognathic surgery were randomly allocated to either sevoflurane or desflurane anaesthesia. The incidence of emergence agitation and possible causative factors were then compared between the groups.

RESULTS

The incidence of emergence agitation was lower in the desflurane group than in the sevoflurane group (24% vs. 71%, P < 0.001). In addition, the time intervals between the discontinuation of anaesthetics and the first response, extubation, and discharge from post-anaesthesia care unit were significantly shorter in the desflurane group (P = 0.002, P < 0.001 and P = 0.003, respectively). The other variables were similar in the two groups.

CONCLUSIONS

In adults undergoing orthognathic surgery, desflurane anaesthesia was associated with less emergence agitation than was sevoflurane anaesthesia.

Postanaesthetic emergence agitation in adult patients after general anaesthesia for urological surgery

Objective

To investigate the incidence and risk factors for emergence agitation in the postanaesthetic care unit (PACU), in adult patients undergoing urological surgery.

Methods

Medical records were retrospectively reviewed. Preoperative, intraoperative and postoperative variables were evaluated. Emergence agitation was defined as a Riker sedation–agitation score ≥5. Logistic regression analysis was used to determine independent risk factors for emergence agitation.

Results

Emergence agitation was observed in 48/488 (9.8%) patients. Chronic lung disease (odds ratio [OR] 2.72, 95% confidence interval [CI] 1.03, 7.17), duration of surgery (OR 1.01, 95% CI 1.00, 1.01), history of social drinking (OR 2.48, 95% CI 1.25, 4.93), postoperative pain score (OR 1.32, 95% CI 1.14, 1.53), voiding urgency (OR 2.20, 95% CI 1.01, 4.77) and presence of gastric tube (OR 2.85, 95% CI 1.07, 7.54) were independent risk factors for emergence agitation.

Conclusions

Adequate postoperative pain management and prevention of catheter-related bladder discomfort may be helpful in reducing the incidence of emergence agitation in urology patients.

Emergence from general anaesthesia and evolution of delirium signs in the post-anaesthesia care unit

BACKGROUND

Emergence from anaesthesia is often accompanied by signs of delirium, including fluctuating mental status and inattention. The evolution of these signs of delirium requires investigation since delirium in the post-anaesthesia care unit (PACU) may be associated with worse outcomes.

METHODS

Adult patients emerging from anaesthesia were assessed for agitated emergence in the operating room using the Richmond Agitation-Sedation Scale (RASS). The Confusion Assessment Method for the Intensive Care Unit was then used to evaluate delirium signs at PACU admission and during PACU stay at 30 min, 1 h, and discharge. Signs consistent with delirium were classified as hyperactive vs hypoactive based upon a positive CAM-ICU assessment and the concomitant RASS score. Multivariable logistic regression was utilized to assess potential risk factors for delirium during PACU stay including age, American Society of Anesthesiologists classification, and opioid and benzodiazepine exposure.

RESULTS

Among 400 patients enrolled, 19% had agitated emergence. Delirium signs were present at PACU admission, 30 min, 1 h, and PACU discharge in 124 (31%), 59 (15%), 32 (8%), and 15 (4%) patients, respectively. In patients with delirium signs, hypoactive signs were present in 56% at PACU admission and in 92% during PACU stay. Perioperative opioids were associated with delirium signs during PACU stay (P=0.02).

CONCLUSIONS

A significant proportion of patients develop delirium signs in the immediate postoperative period, primarily manifesting with a hypoactive subtype. These signs often persist to PACU discharge, suggesting the need for structured delirium monitoring in the PACU to identify patients potentially at risk for worse outcomes in the postoperative period.

Incidence, Risk Factors and Consequences of Emergence Agitation in Adult Patients after Elective Craniotomy for Brain Tumor: A Prospective Cohort Study

Emergence agitation is a frequent complication that can have serious consequences during recovery from general anesthesia. However, agitation has been poorly investigated in patients after craniotomy. In this prospective cohort study, adult patients were enrolled after elective craniotomy for brain tumor. The sedation-agitation scale was evaluated during the first 12 hours after surgery. Agitation developed in 35 of 123 patients (29%). Of the agitated patients, 28 (80%) were graded as very and dangerously agitated. By multivariate stepwise logistic regression analysis, independent predictors for agitation included male sex, history of long-term use of anti-depressant drugs or benzodiazepines, frontal approach of the operation, method and duration of anesthesia and presence of endotracheal intubation. Total intravenous anesthesia and balanced anesthesia with short duration were protective factors. Emergence agitation was associated with self-extubation (8.6% vs 0%, P = 0.005). Sedatives were administered more in agitated patients than non-agitated patients (85.7% vs 6.8%, P<0.001). In conclusion, emergence agitation was a frequent complication in patients after elective craniotomy for brain tumors. The clarification of risk factors could help to identify the high-risk patients, and then to facilitate the prevention and treatment of agitation. For patients undergoing craniotomy, greater attention should be paid to those receiving a frontal approach for craniotomy and those anesthetized under balanced anesthesia with long duration. More researches are warranted to elucidate whether total intravenous anesthesia could reduce the incidence of agitation after craniotomy.

Trial Registration

ClinicalTrials.gov NCT00590499.

Alterations in the functional connectivity of frontal lobe networks preceding emergence delirium in children

BACKGROUND

This study aimed to characterize the electroencephalogram in children who emerged with emergence delirium (ED) compared with children without ED using methods that involved the assessment of cortical functional connectivity.

METHODS

Children aged 5 to 15 yr had multichannel electroencephalographic recordings during induction and emergence from anesthesia during minor surgical procedures. Of these, five children displayed ED after sevoflurane anesthesia. Measures of cortical functional connectivity previously used to evaluate anesthetic action in adults were compared between ED and age-, sex-, and anesthetic-matched non-ED children during emergence from anesthesia.

RESULTS

At the termination of sevoflurane anesthesia, the electroencephalogram in both ED and control patients showed delta frequency slowing and frontally dominant alpha activity, followed by a prolonged state with low-voltage, fast frequency activity (referred to as an indeterminate state). In children with ED, arousal with delirious behavior and a variety of electroencephalogram patterns occurred during the indeterminate state, before the appearance of normal wake or sleep patterns. The electroencephalogram in children without ED progressed from the indeterminate state to classifiable sleep or drowsy states, before peaceful awakening. Statistically significant differences in frontal lobe functional connectivity were identified between children with ED and non-ED.

CONCLUSIONS

ED is associated with arousal from an indeterminate state before the onset of sleep-like electroencephalogram patterns. Increased frontal lobe cortical functional connectivity observed in ED, immediately after the termination of sevoflurane anesthesia, will have important implications for the development of methods to predict ED, the design of preventative strategies, and efforts to better understand its pathophysiology.

Electrical stimulation of the ventral tegmental area induces reanimation from general anesthesia

BACKGROUND

Methylphenidate or a D1 dopamine receptor agonist induces reanimation (active emergence) from general anesthesia. The authors tested whether electrical stimulation of dopaminergic nuclei also induces reanimation from general anesthesia.

METHODS

In adult rats, a bipolar insulated stainless steel electrode was placed in the ventral tegmental area (VTA, n = 5) or substantia nigra (n = 5). After a minimum 7-day recovery period, the isoflurane dose sufficient to maintain loss of righting was established. Electrical stimulation was initiated and increased in intensity every 3 min to a maximum of 120 µA. If stimulation restored the righting reflex, an additional experiment was performed at least 3 days later during continuous propofol anesthesia. Histological analysis was conducted to identify the location of the electrode tip. In separate experiments, stimulation was performed in the prone position during general anesthesia with isoflurane or propofol, and the electroencephalogram was recorded.

RESULTS

To maintain loss of righting, the dose of isoflurane was 0.9% ± 0.1 vol%, and the target plasma dose of propofol was 4.4 ± 1.1 µg/ml (mean ± SD). In all rats with VTA electrodes, electrical stimulation induced a graded arousal response including righting that increased with current intensity. VTA stimulation induced a shift in electroencephalogram peak power from δ (<4 Hz) to θ (4-8 Hz). In all rats with substantia nigra electrodes, stimulation did not elicit an arousal response or significant electroencephalogram changes.

CONCLUSIONS

Electrical stimulation of the VTA, but not the substantia nigra, induces reanimation during general anesthesia with isoflurane or propofol. These results are consistent with the hypothesis that dopamine release by VTA neurons, but not substantia nigra neurons, induces reanimation from general anesthesia.

Brain areas that influence general anesthesia

This document reviews the literature on local brain manipulation of general anesthesia in animals, focusing on behavioral and electrographic effects related to hypnosis or loss of consciousness. Local inactivation or lesion of wake-active areas, such as locus coeruleus, dorsal raphe, pedunculopontine tegmental nucleus, perifornical area, tuberomammillary nucleus, ventral tegmental area and basal forebrain, enhanced general anesthesia. Anesthesia enhancement was shown as a delayed emergence (recovery of righting reflex) from anesthesia or a decrease in the minimal alveolar concentration that induced loss of righting. Local activation of various wake-active areas, including pontis oralis and centromedial thalamus, promoted behavioral or electrographic arousal during maintained anesthesia and facilitated emergence. Lesion of the sleep-active ventrolateral preoptic area resulted in increased wakefulness and decreased isoflurane sensitivity, but only for 6 days after lesion. Inactivation of any structure within limbic circuits involving the medial septum, hippocampus, nucleus accumbens, ventral pallidum, and ventral tegmental area, amygdala, entorhinal and piriform cortex delayed emergence from anesthesia, and often reduced anesthetic-induced behavioral excitation. In summary, the concept that anesthesia works on the sleep-wake system has received strong support from studies that inactivated/lesioned or activated wake-active areas, and weak support from studies that lesioned sleep-active areas. In addition to the conventional wake-sleep areas, limbic structures such as the medial septum, hippocampus and prefrontal cortex are also involved in the behavioral response to general anesthesia. We suggest that hypnosis during general anesthesia may result from disrupting the wake-active neuronal activities in multiple areas and suppressing an atropine-resistant cortical activation associated with movements.

Emergence delirium

Emergence delirium (ED) is a well-known phenomenon in the postoperative period. However, the literature concerning this clinical problem is limited. This review evaluates the literature with respect to epidemiology and risk factors. Treatment strategies are discussed. The review concludes that there is a need for guidelines concerning diagnosis and treatment of ED. Risk factors should be investigated further in the clinical setting in the future.

Inadequate emergence after anesthesia: emergence delirium and hypoactive emergence in the Postanesthesia Care Unit

STUDY OBJECTIVE

To evaluate the frequency, determinants, and outcome of inadequate emergence after elective surgery in the Postanesthesia Care Unit (PACU).

DESIGN

Prospective observational study.

SETTING

12-bed PACU of a tertiary-care hospital in a major metropolitan area.

PATIENTS

266 adult patients admitted to the PACU.

INTERVENTION

To evaluate inadequate emergence, the Richmond Agitation and Sedation Scale (RASS) was administered to patients 10 minutes after their admission to the PACU.

MEASUREMENTS

Demographic data, perioperative variables, and postoperative length of stay (LOS) in the PACU and the hospital were recorded.

MAIN RESULTS

40 (15%) patients showed symptoms of inadequate emergence: 17 patients (6.4%) screened positive for emergence delirium and 23 patients (8.6%) showed hypoactive emergence. Determinants of emergence delirium were longer duration of preoperative fasting (P = 0.001), higher visual analog scale (VAS) scores for pain (P = 0.002), and major surgical risk (P = 0.001); these patients had a higher frequency of postoperative delirium (P = 0.017) and had higher nausea VAS score 6 hours after surgery (P = 0.001). Determinants of hypoactive emergence were duration of surgery (P = 0.003), amount of crystalloids administered during surgery (P = 0.002), residual neuromuscular block (P < 0.001), high-risk surgery (P = 0.002), and lower core temperature on PACU admission (P = 0.028); these patients also had more frequent residual neuromuscular block (P < 0.001) postoperative delirium (P < 0.001), and more frequent adverse respiratory events (P = 0.02). Patients with hypoactive emergence had longer PACU and hospital LOS.

CONCLUSIONS

Preventable determinants for emergence delirium were higher postoperative pain scores and longer fasting times. Hypoactive emergence was associated with longer postoperative PACU and hospital LOSs.

Comparative evaluation of incidence of emergence agitation and post-operative recovery profile in paediatric patients after isoflurane, sevoflurane and desflurane anaesthesia

BACKGROUND

Emergence agitation (EA), although well documented in the clinical literature, still has uncertainties and confusion abound on this subject because of the absence of a clear definition and lack of reliable and valid assessment tools.

AIM

To compare the incidence and severity of EA and recovery characteristics in paediatric patients under isoflurane, sevoflurane or desflurane anaesthesia and evaluate the effect of age and duration of anaesthesia on the incidence of EA.

SETTINGS AND DESIGN

Randomized prospective double-blinded study.

METHODS

Seventy-five American Society of Anaesthesiologists I and II patients, aged between 4 months and 7 years, were included in the study. Patients were induced with sevoflurane and oxygen. Anaesthesia was maintained with O(2) + N(2)O and isoflurane, sevoflurane or desflurane according to randomization. Caudal block and paracetamol suppository was administered before the surgical incision. In the Post-Anesthesia Care Unit (PACU), degree of agitation was assessed using the Paediatric Anaesthesia Emergence Delirium Scale. Aldrette score, Face, Legs, Activity, Cry, Consolability score and any adverse events were noted.

STATISTICAL ANALYSIS

Chi-square/Fischer exact test was applied for categorical variables; for continuous variables, the analysis of variance/non-parametric Kruskall-Wallis test was applied. Two-sample t-test/non-parametric Wisconsin Mann-Whitney test was applied between the two groups. Statistical significance was determined at P<0.05.

RESULTS

Incidence and intensity of EA were comparable in all three groups. Age and duration of anaesthesia do not appear to have any bearing on the incidence of EA. Rapid emergence with sevoflurane and desflurane did not translate into early discharge from PACU.

CONCLUSIONS

EA is a multifactorial syndrome. More well-conducted studies using validated scales and standardized protocols should be carried out to better understand this phenomenon.

Guidelines for perioperative care in elective rectal/pelvic surgery: Enhanced Recovery After Surgery (ERAS®) Society recommendations

BACKGROUND

This review aims to present a consensus for optimal perioperative care in rectal/pelvic surgery, and to provide graded recommendations for items for an evidenced-based enhanced recovery protocol.

METHODS

Studies were selected with particular attention paid to meta-analyses, randomized controlled trials and large prospective cohorts. For each item of the perioperative treatment pathway, available English-language literature was examined, reviewed and graded. A consensus recommendation was reached after critical appraisal of the literature by the group.

RESULTS

For most of the protocol items, recommendations are based on good-quality trials or meta-analyses of good-quality trials (evidence grade: high or moderate).

CONCLUSIONS

Based on the evidence available for each item of the multimodal perioperative care pathway, the Enhanced Recovery After Surgery (ERAS) Society, European Society for Clinical Nutrition and Metabolism (ESPEN) and International Association for Surgical Metabolism and Nutrition (IASMEN) present a comprehensive evidence-based consensus review of perioperative care for rectal surgery.

Epidemiology and risk factors for delirium across hospital settings

Delirium is one of the most common causes of acute end-organ dysfunction across hospital settings, occurring in as high as 80% of critically ill patients that require intensive care unit (ICU) care. The implications of this acute form of brain injury are profound. Across many hospital settings (emergency department, general medical ward, postoperative and ICU), a patient who experiences delirium is more likely to experience increased short- and long-term mortality, decreases in long-term cognitive function, increases in hospital length of stay and increased complications of hospital care. With the development of reliable setting-specific delirium-screening instruments, researchers have been able to highlight the predisposing and potentially modifiable risk factors that place patients at highest risk. Among the large number of risk factors discovered, administration of potent sedative medications, most notably benzodiazepines, is most consistently and strongly associated with an increased burden of delirium. Alternatively, in both the hospital and ICU, delirium can be prevented with the application of protocols that include early mobility/exercise. Future studies must work to understand the epidemiology across settings and focus upon modifiable risk factors that can be integrated into existing delirium prevention and treatment protocols.

Pharmacological risk factors for delirium after cardiac surgery: a review

PURPOSE

The objective of this review is to evaluate the literature on medications associated with delirium after cardiac surgery and potential prophylactic agents for preventing it.

SOURCE

Articles were searched in MEDLINE, Cumulative Index to Nursing and Allied Health, and EMBASE with the MeSH headings: delirium, cardiac surgical procedures, and risk factors, and the keywords: delirium, cardiac surgery, risk factors, and drugs. Principle inclusion criteria include having patient samples receiving cardiac procedures on cardiopulmonary bypass, and using DSM-IV-TR criteria or a standardized tool for the diagnosis of delirium.

PRINCIPAL FINDINGS

Fifteen studies were reviewed. Two single drugs (intraoperative fentanyl and ketamine), and two classes of drugs (preoperative antipsychotics and postoperative inotropes) were identified in the literature as being independently associated with delirium after cardiac surgery. Another seven classes of drugs (preoperative antihypertensives, anticholinergics, antidepressants, benzodiazepines, opioids, and statins, and postoperative opioids) and three single drugs (intraoperative diazepam, and postoperative dexmedetomidine and rivastigmine) have mixed findings. One drug (risperidone) has been shown to prevent delirium when taken immediately upon awakening from cardiac surgery. None of these findings was replicated in the studies reviewed.

CONCLUSION

These studies have shown that drugs taken perioperatively by cardiac surgery patients need to be considered in delirium risk management strategies. While medications with direct neurological actions are clearly important, this review has shown that specific cardiovascular drugs may also require attention. Future studies that are methodologically consistent are required to further validate these findings and improve their utility.

A comparative study of emergence agitation between sevoflurane and propofol anesthesia in adults after closed reduction of nasal bone fracture

BACKGROUND

Emergence agitation is associated with increased morbidity and hospital costs. However, there have been few reports in the medical literature on the occurrence of emergence agitation in adults. The aim of this study was to compare emergence agitation between sevoflurane and propofol anesthesia in adults after closed reduction of nasal bone fracture.

METHODS

Forty adults (ASA I-II, 20-60 yr) undergoing closed reduction of nasal bone fracture were randomly assigned to either sevoflurane or propofol group and anesthesia was maintained with sevoflurane or propofol. The bispectral index (BIS) was monitored and maintained within 40-60. At the end of surgery, patients were transported to the post anesthetic care unit (PACU) and agitation state scale was checked by Aono's four-point scale (AFPS). Emergence agitation was defined as and AFPS score of 3 or 4. Pain score were measured by numeric rating scale (NRS) on arrival and peak value at PACU.

RESULTS

Nine (45.0%) patients in the sevoflurane group and 2 (10.0%) patients in the propofol group developed emergence agitation in the PACU (P = 0.031). There was no correlation between peak NRS and Aono's four-point scale.

CONCLUSIONS

Propofol may decrease incidence of emergence agitation compared to sevoflurane in adults undergoing closed reduction of nasal bone fracture.

Early postoperative cognitive dysfunction and postoperative delirium after anaesthesia with various hypnotics: study protocol for a randomised controlled trial--the PINOCCHIO trial

Background

Postoperative delirium can result in increased postoperative morbidity and mortality, major demand for postoperative care and higher hospital costs. Hypnotics serve to induce and maintain anaesthesia and to abolish patients' consciousness. Their persisting clinical action can delay postoperative cognitive recovery and favour postoperative delirium. Some evidence suggests that these unwanted effects vary according to each hypnotic's specific pharmacodynamic and pharmacokinetic characteristics and its interaction with the individual patient.

We designed this study to evaluate postoperative delirium rate after general anaesthesia with various hypnotics in patients undergoing surgical procedures other than cardiac or brain surgery. We also aimed to test whether delayed postoperative cognitive recovery increases the risk of postoperative delirium.

Methods/Design

After local ethics committee approval, enrolled patients will be randomly assigned to one of three treatment groups. In all patients anaesthesia will be induced with propofol and fentanyl, and maintained with the anaesthetics desflurane, or sevoflurane, or propofol and the analgesic opioid fentanyl.

The onset of postoperative delirium will be monitored with the Nursing Delirium Scale every three hours up to 72 hours post anaesthesia. Cognitive function will be evaluated with two cognitive test batteries (the Short Memory Orientation Memory Concentration Test and the Rancho Los Amigos Scale) preoperatively, at baseline, and postoperatively at 20, 40 and 60 min after extubation.

Statistical analysis will investigate differences in the hypnotics used to maintain anaesthesia and the odds ratios for postoperative delirium, the relation of early postoperative cognitive recovery and postoperative delirium rate. A subgroup analysis will be used to categorize patients according to demographic variables relevant to the risk of postoperative delirium (age, sex, body weight) and to the preoperative score index for delirium.

Discussion

The results of this comparative anaesthesiological trial should whether each the three hypnotics tested is related to a significantly different postoperative delirium rate. This information could ultimately allow us to select the most appropriate hypnotic to maintain anaesthesia for specific subgroups of patients and especially for those at high risk of postoperative delirium.

Registered at Trial.gov Number

ClinicalTrials.gov: NCT00507195

Review articles: the effects of perioperative and intensive care unit sedation on brain organ dysfunction

Analgesia and sedation are routinely administered to patients in procedural suites, operating rooms, and intensive care units to permit invasive procedures, prevent pain and anxiety, reduce stress and oxygen consumption, allow mechanical ventilation, and for numerous other patient comfort and safety reasons. Increasing research and evidence, however, has implicated commonly prescribed sedative medications as risk factors for untoward events and worse patient outcomes, including brain organ dysfunction manifested as delirium and coma. The effect of sedatives on outcomes is also influenced by the depth of sedation, making it imperative to reduce total exposure to this class of medications. Juxtaposing the widespread necessity and use of sedation with the cost of acute and long-term cognitive dysfunction to patients and society, physicians must now strive to balance patients' demands and requisite for comfort with their own oath to do no harm. Fortunately, our methods of sedation and choice of medications can likely mitigate this cognitive risk. In this review, we detail the effects of perioperative and intensive care unit sedation on the development of delirium and cognitive impairment and provide an evidence-based approach towards analgesia and sedation paradigms to improve patient outcomes.