Monitoring of skin conductance to assess postoperative pain intensity

Background. Pain is known to alter the electrogalvanic propertiesof the skin. The aim of this pilot study was to investigatethe influence of postoperative pain on skin conductance (SC)readings. Methods. After obtaining ethical approval and written informedconsent, 25 postoperative patients were asked to quantify theirlevel of pain on a numeric rating scale (NRS, 0–10) atdifferent time points in the recovery room. As a parameter ofSC, the number of fluctuations within the mean SC per second(NFSC) was recorded. Simultaneously, the NRS was obtained frompatients by a different observer who was blinded to the NFSCvalues. Results. Data from 110 readings of 25 patients (14 female, 11male; 21–67 yr) were included. NFSC showed a significantcorrelation with the NRS (r=0.625; P<0.01), whereas heartrate and blood pressure showed no or very weak correlation withthe NRS. NFSC was significantly different between patients withno (NRS=0), mild (NRS=1–3), moderate (NRS=4–5) andsevere (NRS=6–10) pain (no: 0.047, mild: 0.089, moderate:0.242, severe: 0.263; P<0.0001). Post hoc, a cut-off valuefor NFSC (0.1) was calculated above which a pain score >3on the NRS was predicted with sensitivity of 89% and specificityof 74%. Conclusions. The severity of postoperative pain significantlyinfluences SC. Using cut-off values, NFSC may prove a usefultool for pain assessment in the postoperative period.     

Kidney dysfunction in the postoperative period

The development of perioperative acute renal failure is associatedwith a high incidence of morbidity and mortality. Although thisincidence varies with different surgical procedures and withthe definition used for renal failure, we now understand betterthe aetiology of the underlying problem. However, successfulstrategies to provide renal protection or strategies for ‘rescuetherapy’ are either lacking, unsubstantiated by randomizedclinical trials, or show no significant efficacy. The presentreview considers the physiology and pharmacology of the kidney;the characterization of tests of renal function; the cause ofpostoperative renal dysfunction; what is presently availablefor its prevention and treatment; and the effect of postoperativerenal impairment on patient outcome.     

Atelectasis during anaesthesia and in the postoperative period

Transverse sections of lung tissue were studied in patients by computerized tomography during anaesthesia and in the postoperative period. Eight patients were studied during intravenous (thiopentone) and six during inhalational (halothane) anaesthesia. The latter patients were studied during both spontaneous and mechanical ventilation. Five of the patients who underwent surgery for inguinal hernia and five patients in whom laparotomy was performed were studied 1 h and 24 h postoperatively. No patient showed any lung changes while awake preoperatively, and all patients developed dependent, crest-shaped lung densities within 5-10 min of anaesthesia. The densities comprised 3.4% of the lung volume in the caudal (basal) 5 cm of the lung tissue. No significant differences in the size and distribution of the densities were noted between spontaneous breathing and mechanical ventilation during anaesthesia, or between intravenous and inhalational anaesthesia. The densities remained in nine of ten patients 1 h postoperatively, and they remained in five of ten patients 24 h after anaesthesia. The densities are considered to be compression atelectases which may develop as a result of relaxation of the diaphragm. They may be important contributors to postoperative pulmonary complications.     

A comparison of intra-operative or postoperative exposure to music--a controlled trial of the effects on postoperative pain

The effect of intra-operative compared to postoperative music on postoperative pain was evaluated in a controlled trial. In all, 151 patients undergoing day case surgery for inguinal hernia repair or varicose vein surgery under general anaesthesia were randomly allocated to three groups: group 1 listened to music intra-operatively, group 2 listened to music postoperatively and group 3, the control group, listened to 'white noise'. The anaesthetic and postoperative analgesic techniques were standardised. Pain was assessed using a numeric rating scale (0-10) and patients requirements for postoperative morphine, paracetamol and ibuprofen was recorded. The effect of music on nausea, fatigue and anxiety was also investigated. The results showed that patients exposed to music intra-operatively or postoperatively reported significantly lower pain intensity at 1 and 2 h postoperatively and patients in the postoperative music group required less morphine at 1 h compared to the control group. No differences were noted in the other variables. This study demonstrates that there is a short-term pain-reducing effect of music therapy however, the beneficial effects do not differ if the patient is exposed to music intra-operatively or postoperatively.     

Risk factors for postoperative anxiety in adults

We identified risk factors for postoperative anxiety and quantified their effect on 712 adults between 18 and 60 years of age (ASA I-III physical status) undergoing elective surgery under general anaesthesia, neural blockade or both. The measuring instruments were a structured questionnaire, a pain visual analogue scale, the McGill Pain Questionnaire, the State-Trait Anxiety Inventory, the Montgomery-Asberg Depression Rating Scale, a Self-Reporting Questionnaire-20, and a Self-Perception of Future Questionnaire. Multivariate conditional regression modelling taking into account the hierarchical relationship between risk factors revealed that postoperative anxiety was associated with ASA status III (OR = 1.48), history of smoking (1.62), moderate to intense postoperative pain (OR = 2.62) and high pain rating index (OR = 2.35), minor psychiatric disorders (OR = 1.87), pre-operative state-anxiety (OR = 2.65), and negative future perception (OR = 2.20). Neural block anaesthesia (OR = 0.72), systemic multimodal analgesia (OR = 0.62) and neuroaxial opioids with or without local anaesthesia (OR = 0.63) were found to be protective factors against postoperative anxiety.     

Patient preferences for immediate postoperative recovery

Background. Several attempts have been made to evaluate patients’concerns with respect to postoperative recovery. To identifyaspects of postoperative recovery relevant to patients, severalmethodological and statistical approaches have been used. Oneof the first to provide useful information was Fredrick Orkinwho used conjoint analysis. This methodology is usually performedby market researchers to learn about the relative importanceof product attributes. We used conjoint analysis in the presentstudy. Methods. A total of 220 patients undergoing preoperative anaestheticexamination before impending surgery under general anaesthesiawere asked to rate nine scenarios during immediate postoperativerecovery based on four factors (alertness, pain, postoperativenausea and vomiting (PONV), and extra costs) each with threelevels. Using conjoint analysis the relative impact of eachfactor on ranking the scenarios was assessed. Results. The relative importance of the four factors (as a percentageof the preference decision) was PONV (49%), pain (27%), alertness(13%), and additional costs (11%). Conclusion. Avoidance of PONV is a major concern for patientsbefore surgery. Br J Anaesth 2002; 89: 760–1     

Lung function during anesthesia and respiratory insufficiency in the postoperative period: physiological and clinical implications

This review covers the physiological and clinical implications of lung function during anesthesia and respiratory insufficiency in the postoperative period. We have divided it into 3 main sections: 1) lung function changes induced by anesthesia and surgery, in which the impact on pulmonary mechanics, ventilation/perfusion changes and gas exchange are examined; 2) physiological implications of postoperative respiratory function secondary to decreased alveolar ventilation, development of atelectasis, and interstitial lung edema; and 3) clinical implications of postoperative respiratory failure. In this last section we analyze the current therapeutic modalities available to reduce the incidence of postoperative respiratory failure, as well as related morbidity and mortality.     

Ventilatory pattern and associated episodic hypoxaemia in the late postoperative period in the general surgical ward

Episodic oxygen desaturation is frequent in the late postoperative period and seems most pronounced on the second and third postoperative nights. However, the ventilatory pattern has not been described systematically during this period. We studied the ventilatory pattern and associated arterial oxygenation using the Edentrace II equipment (impedance pneumography and pulse oximetry) on the second and third postoperative nights in 28 patients undergoing major abdominal surgery. Ventilatory disturbances were common and included periods of hypopnoea, and obstructive, central and mixed apnoeas. Overall, the median (range) respiratory disturbance index (apnoeas + hypopnoeas per h) was 12 (0-121), with the patients spending 6% (0-65%) of the night in some kind of ventilatory disturbance. It was not possible from pre-operative snoring habits to predict patients who developed postoperative ventilatory disturbances. Overall, 23% (0-100) of the hypopnoeas and 7% (0-100) of the apnoeas were associated with episodic hypoxaemia. In conclusion, ventilatory disturbances were common in the late postoperative period in the general surgical ward and often associated with episodes of oxygen desaturation.     

Neuromuscular monitoring and postoperative residual curarisation: a meta-analysis

We conducted a meta-analysis to examine the effect of intraoperativemonitoring of neuromuscular function on the incidence of postoperativeresidual curarisation (PORC). PORC has been considered presentwhen a patient has a train-of-four (TOF) ratio of < 0.7 or< 0.9. We analysed data from 24 trials (3375 patients) thatwere published between 1979 and 2005. We excluded data on mivacuriumfrom this meta-analysis because only three studies had examinedthe incidence of PORC associated with its use. Long- and intermediate-actingneuromuscular blocking drugs had been given to 662 and 2713patients, respectively. Neuromuscular function was monitoredin 823 patients (24.4%). A simple peripheral nerve stimulatorwas used in 543 patients, and an objective monitor was usedin 280. The incidence of PORC was found to be significantlylower after the use of intermediate neuromuscular blocking drugs.We could not demonstrate that the use of an intraoperative neuromuscularfunction monitor decreased the incidence of PORC.     

参麦注射液预处理对老龄大鼠术后认知功能的影响

目的观察参麦注射液预处理对老龄大鼠术后炎症反应水平和认知功能的影响。方法健康雄性老龄SD大鼠72只,月龄约20个月,体重500~600g。按随机数字表法分为对照组(C组)、参麦注射液组(S组)和布洛芬组(I组),每组24只。S组腹腔注射参麦注射液,I组给予布洛芬悬液灌胃,C组腹腔注射等量生理盐水。七氟醚麻醉下行脾切除术建立老龄大鼠POCD模型。三组大鼠分别于麻醉后即刻、术后即刻和术后1d采集颈静脉血,采用ELISA固相夹心法测定IL~(-1)β、IL-6和TNF-α浓度。于术前、术后1、3和7d进行Morris水迷宫实验和旷场实验,记录大鼠的逃避潜伏期、平台穿越次数、中央格停留时间、修饰次数和直立次数。结果术后即刻,S组和I组IL~(-1)β、IL-6和TNF-α浓度均明显低于C组(P0.01或P0.05);术后1d,I组IL~(-1)β与S组和I组IL-6的浓度均明显低于C组(P0.01或P0.05)。与术前比较,术后1、3dC组和S组的逃避潜伏期明显延长(P0.05),平台穿越次数明显减少(P0.01或P0.05),中央格停留时间明显延长(P0.01或P0.05),修饰和直立次数均明显减少(P0.01或P0.05)。与C组和S组比较,术后1、3dI组逃避潜伏期明显缩短(P0.01或P0.05),平台穿越次数均明显增多(P0.01或P0.05),中央格停留时间明显缩短(P0.01),修饰次数和直立次数均明显增多(P0.01或P0.05)。结论参麦注射液预处理可减轻手术后炎症反应,但对POCD无明显影响。     

Development of postoperative delirium in relation to a room change in the general surgical unit

To analyze the relationship between the development of postoperative delirium and a change of the patient's room, 1,006 cases of patients who had undergone surgery with general anesthesia were reviewed. Postoperative delirium developed in 84 (8.3%) cases. On the basis of symptomatic features, postoperative delirium was divided into four types: (1) excitement type, (2) excitement-hallucination type, (3) hallucination type, and (4) disorientation type. Of the 31 excitement-type cases, 21 developed within the 2nd postoperative day (POD) while 27 of 29 hallucination types developed after POD 2. Of 29 hallucination types, 22 developed after a room change while 20 of these 22 cases were transferred to a single room before POD 2. A quiet, dark, and isolated environment in a single room is suggested to contribute to the development of hallucinations. The development of postoperative delirium with hallucinations alone should thus be taken into consideration whenever a room change is decided.     

Continuous physostigmine combined with morphine-based patient-controlled analgesia in the postoperative period

BACKGROUND: Recently, new drugs and techniques for the treatment of postoperative pain were introduced, with the goal of enhancing opiates' analgesia while minimizing their side-effects. Cholinergic agents play an antinociceptive role, but their clinical use is quite limited, due to side-effects. Physostigmine is a cholinesterase inhibitor, which crosses the blood-brain barrier and elevates brain acetylcholine level. Physostigmine can produce analgesia by itself, and enhance opiate analgesia; but these effects are of short duration following bolus administration. METHODS: We compared pain intensity and morphine consumption in two postoperative treatment groups: One group received continuous physostigmine infusion combined with morphine-based patient-controlled analgesia (PCA), and the other received PCA alone. Cholinergic anti-inflammatory pathways have recently been described. We therefore also compared changes in proinflammatory cytokine production in the two pain management groups. RESULTS: Continuous infusion of physostigmine combined with morphine-based PCA in the postoperative period significantly reduced opiate consumption, and enhanced the analgesic response. Patients in the physostigmine group also exhibited reduced ex-vivo production of the proinflammatory cytokine, IL-1beta. At the same time, physostigmine increased nausea and vomiting, mostly in the first 2 h of the postoperative period. CONCLUSIONS: Physostigmine combined with morphine in the postoperative period reduced morphine consumption, enhanced analgesia, and attenuated production of the proinflammatory cytokine, IL-1beta. This latter finding may account for the decreased pain observed in this group; this cytokine is known to mediate basal pain sensitivity and induce hyperalgesia in inflammatory conditions. Taking into account the other potential beneficial effects of physostigmine, we suggest that a continuous infusion of physostigmine should be considered as a useful component in multimodal postoperative analgesia.     

全身麻醉药与术后认知功能障碍及阿尔茨海默病

术后认知功能障碍(POCD)的病因复杂,在老年患者中较多见,但其机制尚未明确.全麻药在POCD发生中的作用及其机制已有许多研究,结果复杂而多样.另外,有一些动物或离体研究表明全麻药可促发阿尔茨海默病(AD)的发病过程并可能因此促发AD的发病和导致POCD.因此,研究全麻药在POCD和术后AD发病中的作用,特别是探求其中可能存在的共同机制是有意义的.     

MRI evaluation of axillary and intramammary lymph nodes in the postoperative period

Our study aimed to evaluate if breast‐conserving surgery and adjuvant treatment could affect the morphological features of axillary and intramammary lymph nodes on magnetic resonance imaging (MRI) in patients with invasive breast cancer and clinically negative axilla. In this single‐center study, we retrospectively evaluated 50 patients who had (a) breast‐conserving surgery, (b) clinically negative axilla, (c) preoperative MRI within 3 months before surgery, and (d) postoperative MRI within 12 months after surgery. Axillary and intramammary lymph nodes on postoperative MRI were identified and then compared with preoperative MRI by two breast radiologists with regards to the following: enlargement, cortical thickening, presence of fatty hilum, irregularity, heterogeneity, matting, and axillary lymph node asymmetry. Three hundred and two axillary and eight intramammary lymph nodes were evaluated. Enlargement and cortical thickening were seen in 5/50 (10%) patients in three axillary and two intramammary lymph nodes. None of the lymph nodes on postoperative MRI demonstrated occurrence of lack of fatty hilum, irregularity, heterogeneity, matting or axillary lymph node asymmetry. No evidence of recurrence was observed on 2‐year follow‐up. Lymph node enlargement and cortical thickening may be observed in a few patients in the postoperative period. Nevertheless, in patients with clinically negative axilla, these changes in morphology are often related to treatment rather than malignancy and favor short‐term follow‐up as an alternative to lymph node biopsy.     

Preoperative anxiety level is not associated with postoperative negative behavioral changes in premedicated children

Background

Anesthesia preinduction anxiety in children can according to some studies lead to long-term anxiety and negative behavioral changes (NBC), while other studies have not found this effect. This secondary analysis from a recent premedication trial comparing clonidine and midazolam aimed to test the relation between preoperative anxiety assessed with modified Yale Preoperative Anxiety Scale (mYPAS) and postoperative NBCs assessed with Post Hospital Behavior Questionnaire (PHBQ), regardless of premedication type.

Methods

This is a planned secondary analysis from a published premedication comparison trial in an outpatient surgery cohort, children aged 2–7 years. Participant and preoperative factors, particularly preoperative anxiety as mYPAS scores, were assessed for association with development of postoperative NBCs.

Results

Fifty-four of the 115 participants had high preinduction anxiety (mYPAS >30), and 19 of 115 developed >3 postoperative NBCs 1 week after surgery. There was no association between preinduction anxiety level as mYPAS scores and the development of postoperative NBCs at 1 week after surgery (10 of 19 had both, p = .62) nor after 4- or 26-weeks post-surgery. Only lower age was associated with development of NBCs postoperatively.

Conclusions

Based on the findings from this cohort, high preinduction anxiety does not appear to be associated with NBCs postoperatively in children premedicated with clonidine or midazolam.     

Safety of endoscopy in the immediate postoperative period following gastric anastomosis

Summary The safety of gastrointestinal endoscopy in the immediate postoperative period following partial gastrectomy was assessed in ten dogs. Endoscopy was performed preoperatively and at 1, 2, 3, and 7 days postoperatively. The mean pressures required to perform an adequate endoscopy varied from 17 to 20 mm Hg. Following partial gastrectomy, the abdominal wall was closed with a zipper to facilitate inspection of the gastric anastomosis. No leakage of air or intra-abdominal abscesses were seen following endoscopy. The results of this study suggest that endoscopy can be safely performed in the immediate postgastrectomy period.     

Correlation of postoperative pain to quality of recovery in the immediate postoperative period

BACKGROUND AND OBJECTIVES: It is unclear whether the severity of postoperative pain may affect patients' quality of recovery in the immediate postoperative period (within 2 weeks of surgery). METHODS: This was a prospective, observational study in patients undergoing elective radical retropubic prostatectomy. All patients received a standardized intraoperative general or spinal anesthetic followed by intravenous patient-controlled analgesia. Visual analog scores for pain at rest, pain with activity, and nausea along with the QoR, an instrument validated to assess quality of recovery in the postoperative period, and Brief Fatigue Inventory were assessed on postoperative days 1 to 3, 7, and 30. The Epworth Sleepiness Scale was assessed on postoperative days 7 and 30. RESULTS: We found that the severity of pain both at rest and with activity correlated with a decrease in quality of recovery as assessed by the QoR. CONCLUSIONS: Our findings suggest that an increase in postoperative pain is correlated with a decrease in a patient's quality of recovery in the immediate postoperative period.