The efficacy, applicability and side-effects of postoperative intravenous patient-controlled morphine analgesia: an audit of 1233 Chinese patients

Process, structural, and outcome quality indicators to support perioperative opioid stewardship: a rapid review

Opioids are effective analgesics but can cause harm. Opioid stewardship is key to ensuring that opioids are used effectively and safely. There is no agreed set of quality indicators relating to the use of opioids perioperatively. This work is part of the Yorkshire Cancer Research Bowel Cancer Quality Improvement programme and aims to develop useful quality indicators for the improvement of care and patient outcomes at all stages of the perioperative journey.A rapid review was performed to identify original research and reviews in which quality indicators for perioperative opioid use are described. A data tool was developed to enable reliable and reproducible extraction of opioid quality indicators.A review of 628 abstracts and 118 full-text publications was undertaken. Opioid quality indicators were identified from 47 full-text publications. In total, 128 structure, process and outcome quality indicators were extracted. Duplicates were merged, with the final extraction of 24 discrete indicators. These indicators are based on five topics: patient education, clinician education, pre-operative optimization, procedure, and patient-specific prescribing and de-prescribing and opioid-related adverse drug events.The quality indicators are presented as a toolkit to contribute to practical opioid stewardship. Process indicators were most commonly identified and contribute most to quality improvement. Fewer quality indicators relating to intraoperative and immediate recovery stages of the patient journey were identified. An expert clinician panel will be convened to agree which of the quality indicators identified will be most valuable in our region for the management of patients undergoing surgery for bowel cancer.

Risk factors for emergence agitation during the awakening period in elderly patients after total joint arthroplasty: a retrospective cohort study

OBJECTIVES

This study aimed to explore the incidence and risk factors for emergence agitation (EA) in elderly patients who underwent total joint arthroplasty (TJA) under general anaesthesia, and to assess their predictive values.

DESIGN

Single-centre retrospective cohort study.

SETTING

A 1600-bed general tertiary hospital in China.

PARTICIPANTS

This study enrolled 421 elderly patients scheduled for elective primary TJA under general anaesthesia.

PRIMARY AND SECONDARY OUTCOME MEASURES

EA was assessed using the Richmond Agitation Sedation Scale during the awakening period after surgery in the post-anaesthesia care unit. Risk factors for EA were identified using univariate and multivariable logistic analyses. The receiver operating characteristic (ROC) curve was used to assess the predictive values of the risk factors for EA.

RESULTS

The incidence of EA in elderly patients who underwent TJA was 37.6%. According to the multivariable logistic analysis, postoperative pain (95% CI: 1.951 to 3.196), male sex (95% CI: 1.781 to 6.435), catheter-related bladder discomfort (CRBD) (95% CI: 4.001 to 15.392) and longer fasting times for solids (95% CI: 1.260 to 2.301) and fluids (95% CI: 1.263 to 2.365) were independent risk factors for EA. As shown by the ROC analysis, postoperative pain and fasting times for solids and fluids had good predictive values, with areas under the ROC curve equalling 0.769, 0.753 and 0.768, respectively.

CONCLUSIONS

EA is a common complication after TJA in elderly patients. Some risk factors, including postoperative pain, male sex, CRBD and longer fasting times, can increase the incidence of EA. These risk factors may contribute to identifying high-risk patients, which facilitates the development of effective strategies to prevent and treat EA.

TRIAL REGISTRATION NUMBER

ChiCTR1800020193.

Predictors of Catheter-Related Bladder Discomfort After Surgery: A Literature Review

Background

Indwelling bladder catheters are routinely used in clinical practice. Patients may experience postoperative indwelling catheter-related bladder discomfort (CRBD). This study aimed to perform a literature review to identify predictors of postoperative CRBD.

Methods

We searched PubMed for relevant articles published between 2000 and 2020 using the search items "CRBD", "catheter-related bladder discomfort", and "prediction". Additionally, we searched for articles that matched the research objectives from the references of the extracted articles. We included only prospective observational studies involving human participants and excluded interventional studies, observational studies that did not report sample sizes, or observational studies that did not research on predictors of CRBD. We narrowed our search to the keyword "prediction" and found five references. We selected five studies that met the objectives of the study as the target literature.

Results

Using the keywords "CRBD" and "catheter-related bladder discomfort", we identified 69 published articles. The results were narrowed down by the keyword "prediction", and five studies that recruited 1,147 patients remained. The predictors of CRBD can be divided into four factors: 1) patient factors; 2) surgical factors; 3) anesthesia factors; and 4) device and insertion technique factors.

Conclusion

Our study suggests that patients with predictors of CRBD should be closely monitored to reduce postoperative patient suffering, and their quality of life should be improved after anesthesia.

Sex-Related Differences in Pharmacological Response to CNS Drugs: A Narrative Review

In the last decades, both animal and human studies have neglected female subjects with the aim of evading a theorized intricacy of feminine hormonal status. However, clinical experience proves that pharmacological response may vary between the two sexes since pathophysiological dissimilarities between men and women significantly influence the pharmacokinetics and pharmacodynamics of drugs. Sex-related differences in central nervous system (CNS) medication are particularly challenging to assess due to the complexity of disease manifestation, drugs’ intricate mechanisms of action, and lack of trustworthy means of evaluating the clinical response to medication. Although many studies showed contrary results, it appears to be a general tendency towards a certain sex-related difference in each pharmacological class. Broadly, opioids seem to produce better analgesia in women especially when they are administered for a prolonged period of time. On the other hand, respiratory and gastrointestinal adverse drug reactions (ADRs) following morphine therapy are more prevalent among female patients. Regarding antidepressants, studies suggest that males might respond better to tricyclic antidepressants (TCAs), whereas females prefer selective serotonin reuptake inhibitors (SSRI), probably due to their tolerance to particular ADRs. In general, studies missed spotting any significant sex-related differences in the therapeutic effect of antiepileptic drugs (AED), but ADRs have sex variations in conjunction with sex hormones’ metabolism. On the subject of antipsychotic therapy, women appear to have a superior response to this pharmacological class, although there are also studies claiming the opposite. However, it seems that reported sex-related differences regarding ADRs are steadier: women are more at risk of developing various side effects, such as metabolic dysfunctions, cardiovascular disorders, and hyperprolactinemia. Taking all of the above into account, it seems that response to CNS drugs might be occasionally influenced by sex as a biological variable. Nonetheless, although for each pharmacological class, studies generally converge to a certain pattern, opposite outcomes are standing in the way of a clear consensus. Hence, the fact that so many studies are yielding conflicting results emphasizes once again the need to address sex-related differences in pharmacological response to drugs.

A preliminary assessment of vital-signs-integrated patient-assisted intravenous opioid analgesia (VPIA) for postsurgical pain

Background

We developed a Vital-signs-integrated Patient-assisted Intravenous opioid Analgesia (VPIA) analgesic infusion pump, a closed-loop vital signs monitoring and drug delivery system which embodied in a novel algorithm that took into account patients’ vital signs (oxygen saturation, heart rate). The system aimed to allow responsive titration of personalized pain relief to optimize pain relief and reduce the risk of respiratory depression. Moreover, the system would be important to enable continuous monitoring of patients during delivery of opioid analgesia.

Methods

Nineteen patients who underwent elective gynecological surgery with postoperative patient controlled analgesia (PCA) with morphine were recruited. The subjects were followed up from their admission to the recovery room/ ward for at least 24 h until assessment of patient satisfaction on the VPIA analgesic infusion pump.

Results

The primary outcome measure of incidence of oxygen desaturation showed all patients had at least one episode of oxygen desaturation (< 95%) during the study period. Only 6 (31.6%) patients had oxygen desaturation that persisted for more than 5 min. The median percentage time spent during treatment that oxygen saturation fell below 95% was 1.9%. Fourteen (73.7%) out of 19 patients encountered safety pause, due to transient oxygen desaturation or bradycardia. The patients’ median [IQR] pain scores at rest and at movement after post-op 24 h were 0.0 [2.0] and 3.0 [2.0], respectively. The average morphine consumption in the first 24 h was 12.5 ± 7.1 mg. All patients were satisfied with their experience with the VPIA analgesic infusion pump.

Conclusions

The use of VPIA analgesic infusion pump, when integrated with continuous vital signs monitor and variable lockout algorithm, was able to provide pain relief with good patient satisfaction.

Trial registration

This study was registered on clinicaltrials.gov registry (NCT02804022) on 28 Feb 2016.

Emergence agitation: current knowledge and unresolved questions

Emergence agitation (EA), also referred to as emergence delirium, can have clinically significant consequences. The mechanism of EA remains unclear. The proposed risk factors of EA include age, male sex, type of surgery, emergency operation, use of inhalational anesthetics with low blood-gas partition coefficients, long duration of surgery, anticholinergics, premedication with benzodiazepines, voiding urgency, postoperative pain, and the presence of invasive devices. If preoperative or intraoperative objective monitoring could predict the occurrence of agitation during emergence, this would help to reduce its adverse consequences. Several tools are available for assessing EA. However, there are no standardized clinical research practice guidelines and its incidence varies considerably with the assessment tool or definition used. Total intravenous anesthesia, propofol, μ-opioid agonists, N-methyl-D-aspartate receptor antagonists, nefopam, α2-adrenoreceptor agonists, regional analgesia, multimodal analgesia, parent-present induction, and preoperative education for surgery may help in preventing of EA. However, it is difficult to identify patients at high risk and apply preventive measures in various clinical situations. The risk factors and outcomes of preventive strategies vary with the methodologies of studies and patients assessed.This review discusses important outcomes of research on EA and directions for future research.

Assessing the Impact of Renal Function on Trajectory of Intravenous Patient-controlled Analgesic Demands Over Time After Open and Laparoscopic Colorectal Surgery Using Latent Curve Analysis

OBJECTIVES

Intravenous patient-controlled analgesia (IVPCA) is often used to relieve pain after colorectal surgery. This study aimed to model the trajectory of analgesic demand over time after colorectal cancer surgery and explore potentially relevant influential factors using latent curve analysis, focusing on laparoscopic-assisted surgery and renal function.

MATERIALS AND METHODS

Patients receiving colorectal surgery with postoperative IVPCA were randomly divided into 2 equal parts to enable model construction and cross validation. Archived data were retrieved from the IVPCA pump. Latent curve modeling with 2 latent variables that reflected the baseline and slope of IVPCA demand trajectory over time was used and the effects of potentially influential factors on the 2 latent variables were evaluated. Goodness-of-fit indices were used to assess the model fit to both the model construction and validation data sets.

RESULTS

Data were collected from 834 patients, of whom 112 had laparoscopic-assisted surgery. Latent curve analysis revealed that body weight increased the baseline analgesic demand over time, whereas increasing age, female sex, poor renal function, and laparoscopic-assisted surgery decrease it. By contrast, only age and weight exerted significant effects on the slope parameter to modify the trajectory of IVPCA demand. Patients with higher age or less weight tended to have a smoother decreasing trajectory of analgesic demands over time. There was good cross validation, as the parameter estimates derived from the model construction data set fitted well to the validation data set (root mean square error of approximation: 0.05).

CONCLUSION

Laparoscopic-assisted surgery and renal function affected the baseline trajectory of IVPCA demand over time, but had no significant effect on its shape.

Postoperative pain and patient-controlled epidural analgesia-related adverse effects in young and elderly patients: a retrospective analysis of 2,435 patients

In this retrospective study, data of 2,435 patients who received fentanyl and ropivacaine-based patient-controlled epidural analgesia (PCEA) for pain relief after elective surgery under general or spinal anesthesia were reviewed. Differences in postoperative pain, incidence of patient-controlled analgesia (PCA)-related adverse effects, and risk factors for the need for rescue analgesics for 48 hours postsurgery in young (age 20–39 years) and elderly (age ≥70 years) patients were evaluated. Although there were no significant differences in postoperative pain intensity between the two groups until 6 hours postsurgery, younger patients experienced greater postoperative pain intensity compared with older patients 6–48 hours postsurgery. While younger patients exhibited greater incidence of numbness, motor weakness, and discontinuation of PCA postsurgery, elderly patients exhibited greater incidence of hypotension, nausea/vomiting, rescue analgesia, and antiemetic administration. Upon multivariate analysis, low fentanyl dosage and history of smoking were found to be associated with an increased need for rescue analgesia among younger patients, while physical status classification III/IV and thoracic surgery were associated with a decreased need for rescue analgesia among the elderly. Discontinuation of PCA was more frequent among younger patients than the elderly (18.5% vs 13.5%, P=0.001). Reasons for discontinuation of PCA among young and elderly patients, respectively, were nausea and vomiting (6.8% vs 26.6%), numbness or motor weakness (67.8% vs 11.5%), urinary retention (7.4% vs 8.7%), dizziness (2.2% vs 5.2%), and hypotension (3.1% vs 20.3%). In conclusion, PCEA was more frequently associated with numbness, motor weakness, and discontinuation of PCA in younger patients and with hypotension, nausea/vomiting, and a greater need for rescue analgesics/antiemetics among elderly patients. Therefore, in order to minimize the adverse effects of PCEA and enhance pain relief, different PCEA regimens and administration/prevention strategies should be considered for young and elderly patients.

Influences of gender on postoperative morphine consumption

BACKGROUND

Gender related differences on morphine consumption during postoperative period following abdominal surgeries.

MATERIALS AND METHODS

Four hundred and fifty ASA I & II patients of either sex (male =231, female = 219), between the age group of 18-65 y undergoing elective intra abdominal surgeries under general anaesthesia were included for the study. Patients with preexisting pain either acute or chronic preoperatively were excluded from the study. Anaesthesia and analgesia protocol during surgery was standardized. Postoperatively, a loading dose was given to achieve the visual analogue scale (VAS) of ≤30 and subjects were connected to patient control analgesia (PCA) pump containing 0.4 mg/ml of morphine configured to deliver a bolus dose (1 mg) with a 5 min lock-out period. The total analgesic requirements along with VAS (visual analog scale) score were analysed between males and females in the first 24 h postoperatively. All demographic data and between group comparisons were analysed with student t-test. Within group comparisons were done by using one-way-ANOVA test and Tukey's Honestly significant Difference test.

RESULTS

During the first 24 h, males consumed significantly higher amount of morphine (34.35 ± 6.68 mg) when compared to females (26.78 ± 7.14 mg), p < 0.001.

CONCLUSION

We conclude that men require more morphine in the postoperative period than women.

Sex differences in opioid analgesia and addiction: interactions among opioid receptors and estrogen receptors

Opioids are widely used as the pain reliever and also notorious for being addictive drugs. Sex differences in the opioid analgesia and addiction have been reported and investigated in human subjects and animal models. Yet, the molecular mechanism underlying the differences between males and females is still unclear. Here, we reviewed the literature describing the sex differences in analgesic responses and addiction liabilities to clinically relevant opioids. The reported interactions among opioids, estrogens, opioid receptors, and estrogen receptors are also evaluated. We postulate that the sex differences partly originated from the crosstalk among the estrogen and opioid receptors when stimulated by the exogenous opioids, possibly through common secondary messengers and the downstream gene transcriptional regulators.

Do sex differences exist in opioid analgesia? A systematic review and meta-analysis of human experimental and clinical studies

Although a contribution of sex in opioid efficacy has garnered much attention, the confirmation and direction of any such difference remain elusive. We performed a systematic review of the available literature on sex differences in μ and mixed μ/κ opioid effect on acute and experimental pain. Fifty unique studies (including three unpublished studies) were included in the analyses. Across the 25 clinical studies on μ-opioids there was no significant sex-analgesia association. Restricting the analysis to patient-controlled analgesia (PCA) studies (irrespective of the opioid) yielded greater analgesia in women (n=15, effect size 0.22, 95% c.i. 0.02-0.42, P=0.028). Further restricting the analysis to PCA morphine studies yielded an even greater effect in women (n=11, effect size=0.36, 95% c.i. 0.17-0.56, P=0.003). Meta-regression indicated that the longer the duration of PCA, the difference in effect between the sexes further increased. Across experimental pain studies on μ-opioids women had greater antinociception from opioids (n=11, effect size=0.35; 95% c.i. 0.01-0.69, P=0.047), which was predominantly due to 6 morphine studies. Female patients had greater μ/κ opioid analgesia (n=7, effect size 0.84; 95% c.i. 0.25-1.43, P=0.005), but no sex-analgesia association was present in experimental studies (n=7). Sex differences exist in morphine-induced analgesia in both experimental pain studies and clinical PCA studies, with greater morphine efficacy in women. The data on non-morphine μ and mixed μ/κ-opioids are less convincing and require further study.

Five-year experience of critical incidents associated with patient-controlled analgesia in an Irish University Hospital

BACKGROUND

Patient-controlled analgesia (PCA) is a common and effective means of managing post-operative pain. We sought to identify factors that may lead to critical incidents (CIs) in patient safety when using PCA in our institution.

METHODS

An observational study of prospectively collected data of patients who received PCA from 2002 to 2006 was performed. All CIs were documented and analysed by staff members of the acute pain service (APS). Cause analysis of CIs was undertaken to determine if measures can be instituted to prevent recurrence of similar events.

RESULTS

Over eight thousand patients (8,240) received PCA. Twenty-seven CIs were identified. Eighteen were due to programming errors. Other CIs included co-administration of opioids and oversedation.

CONCLUSION

In our institution, the largest contributory factor to CIs with PCAs was programming error. Strategies to minimize this problem include better education and surveillance.

Correlates of postoperative pain and intravenous patient-controlled analgesia use in younger and older surgical patients

OBJECTIVE

Age-related patterns in postoperative pain are unclear with reports of no age differences and less pain with age. The objective of this study was to identify correlates of pain and intravenous patient-controlled analgesia (i.v. PCA) morphine use in younger and older patients.

DESIGN

24 hours after surgery, patients completed measures of pain intensity and pain qualities. Surgical factors, i.v. PCA morphine intake, anticholinergic load, polypharmacy, physical status, previous chronic and postoperative pain, and PCA experience were measured.

SETTING

Two academic general hospitals. PATIENTS. Two hundred forty-six general surgery patients ranging in age from 18 to 82 years old.

RESULTS

In older patients, higher pain scores were associated with female gender and previous experience of postoperative PCA. In younger patients, higher pain scores were associated with female gender, previous surgery without PCA, and greater morphine intake. Lower pain was associated with being male, and no previous surgical experience in older patients, and lower morphine intake in younger patients. Morphine intake was higher in patients who were younger, had better physical status, higher anticholinergic load, and experience with PCA. Among younger patients, increased morphine use also was associated with surgical procedure and duration. Higher pain scores were more strongly associated with morphine use among younger than older patients.

CONCLUSIONS

The correlates of postoperative pain and morphine use may differ with age, and the same factor may have different effects across age groups. Research is needed into the mechanisms of these age-specific profiles.

Response to morphine in male and female patients: analgesia and adverse events

BACKGROUND

There is little agreement about a differential response of men and women to opioid analgesics. Some experimental and clinical studies have shown that women have a better response to opioids, others have found no difference, and still others have found opioids to be more effective analgesics for men than women.

OBJECTIVES

To assess sex differences in analgesic response to morphine and incidence of adverse events in patients receiving a dose of 0.1 mg intravenous morphine/kg.

METHODS

Secondary analysis of the control arms of 6 randomized clinical trials that compared 0.1 mg/kg intravenous morphine with other opioids or other doses of morphine in patients aged 21 to 65 with acute pain. The setting was an academic medical center Emergency Department serving primarily Latino and African-American patients. Change in self-reported pain intensity from baseline to 30 minutes postbaseline on a validated and reproducible 11-point numerical rating scale and count of adverse events were the primary outcomes.

RESULTS

The sample consisted of 211 women and 144 men. The mean change in pain from baseline to 30 minutes postbaseline was 3.7 in women, 3.6 men (difference=0.04; 95% confidence interval: -0.52, 0.60). In women without nausea before administration of morphine, the incidence of adverse events was 18.3% versus 10.7% in men without initial nausea (difference=7.6%; 95% confidence interval: -2.0, 17.2).

DISCUSSION

Men and women presenting to the Emergency Department did not have a differential response to a single weight-based dose of morphine for alleviation of acute pain. Women without baseline nausea had more adverse events than men.

Miles to go: an introduction to the 5 Million Lives Campaign

BACKGROUND

The Institute for Healthcare Improvement (IHI)'s 5 Million Lives Campaign targets a reduction of five million instances of harm from December 2006 through December 2008. The campaign continues the six interventions of the 100,000 Lives Campaign and adds six more.

DEFINITION OF MEDICAL HARM AND SETTING THE GOAL

The campaign's aim is to support the reduction of medical harm, so defined: "Unintended physical injury resulting from or contributed to by medical care (including the absence of indicated medical treatment), that requires additional monitoring, treatment, or hospitalization, or that results in death." The goal of a reduction of five million incidents of harm in two years is based on an estimate that 40 to 50 incidents occur per 100 admissions, for a total of 15 million incidents of medical harm each year in the United States. THE 5 MILLION LIVES CAMPAIGN'S "PLATFORM": This campaign's six new interventions address the prevention of pressure ulcers, reduction of methicillin-resistant Staphylococcus aureus (MRSA) infection, prevention of harm from high-alert medications, reduction of surgical complications, delivery of reliable and evidence-based care for congestive heart failure, and getting hospitals' boards of directors on board.

CONCLUSION

Together with complementary partner initiatives, the 5 Million Lives Campaign is intended to act as a major driver of national improvement.

Morphine/ondansetron PCA for postoperative pain, nausea, and vomiting after skull base surgery

OBJECTIVE

Patients who underwent skull base procedures have been noted to experience appreciable pain. This study examines pain after surgery and the effectiveness of patient controlled analgesia (PCA) with combination morphine ondansetron for analgesia and control of emesis.

STUDY DESIGN AND SETTING

A total of 120 skull base surgery patients were randomized to receive placebo, morphine, or morphine ondansetron. Demographic and intraoperative variables were recorded along with pain, nausea, vomiting, and rescue analgesics. Total PCA use, hospital stay, satisfaction, and cost were also compared.

RESULTS

Demographically the groups were similar. Pain was elevated with placebo PCA, and this group averaged twice as many analgesic rescues. Total usage time was lower with placebo PCA. Morphine ondansetron PCA had the lowest pain score with highest satisfaction. Nausea and vomiting was similar but female patients had more vomiting regardless of PCA group.

CONCLUSIONS AND SIGNIFICANCE

The use of morphine PCA reduced pain and did not appreciably increase nausea or vomiting. The addition of ondansetron produced no real benefit and its PCA use cannot be justified.

EBM RATING

A-1b.

Factors Affecting Patient-controlled Analgesia Requirements

BACKGROUND/PURPOSE

Intravenous patient-controlled analgesia (IVPCA) is one of the most widely used postoperative analgesic methods. Many factors could affect the total analgesic consumption of IVPCA. This retrospective study investigated the relationship between patient characteristics and total morphine consumption during a 3-day course of postoperative IVPCA.

METHODS

Patients receiving surgery under general anesthesia with postoperative IVPCA for 3 days during the period between January 2002 and December 2003 were included. Patient data including age, sex, weight, height, body mass index (BMI), operation type and site were collected. Total morphine consumption was recorded at the end of the 3-day IVPCA course. Stepwise regression analyses were conducted to select factors significantly associated with morphine consumption. Stratified analyses were also conducted among different surgical, BMI and age subgroups.

RESULTS

A total of 1308 patients (646 men, 662 women) were included in the analysis. For all operations, weight, age, procedures involving malignant disease, and surgical sites were significantly associated with total morphine consumption. The R and adjusted R2 values of the selected model were 0.509 and 0.256, respectively. Weight was the only common factor among all stratified analyses (all p < 0.001). Age was negatively correlated with morphine consumption. Gender was not a significant factor except in lower abdominal operations. Height was not associated with total morphine consumption. BMI status was not significantly associated with components of the selected factors.

CONCLUSION

This study demonstrated that weight and surgical sites significantly influence total IVPCA requirements. The effect of surgical sites should be considered when evaluating the influence of demographic characteristics on IVPCA demand.

Differences in Postoperative Opioid Consumption in Patients Prescribed Patient-Controlled Analgesia Versus Intramuscular Injection

The purpose of this study was to examine differences in opioid consumption in patients prescribed patient-controlled analgesia (PCA) versus intramuscular injection (IMI) in the early postoperative period after open abdominal surgery. A retrospective audit of 115 patients elicited demographic and clinical data. No significant differences were found between the demographic variables of the PCA and IMI groups. There was a significant difference in the mean opioid dose used during the first 3 postoperative days (p < .01). Mean opioid consumption was 136.89 mg for the PCA group and 50.79 mg for the IMI group. Although there was a reduction in the amount of opioid consumed over the first 3 postoperative days, the PCA group consistently consumed more opioid analgesia compared with the IMI group. Furthermore, there was a disproportionate reduction in opioid consumption between the two groups from Day 1 (r = .34; p < .01) to Day 3 (r = .14; p = .14). This study shows that the amount of analgesia consumed during the postoperative period by patients who had abdominal surgery varied markedly depending on the mode of analgesia (PCA or IMI). The difference in analgesic consumption was also found to increase throughout the 3-day postoperative period. This divergence in the amount of opioid consumption between patients who were prescribed PCA and patients who were prescribed IM analgesia heightens the need for vigilance in assessment and management of pain during the early postoperative period, particularly in patients prescribed IM analgesia on an "as-needed" basis.

Beliefs about appropriate pain behavior: cross-cultural and sex differences between Japanese and Euro-Americans

The Appropriate Pain Behavior Questionnaire (APBQ) was employed to examine the effects of the participants' sex and culture on their beliefs regarding gender-appropriate pain behavior. The APBQ examines beliefs about the social acceptability to male and female participants of the behavioral and verbal expressions of pain by men and women (referents) in the presence of others [Nayak, S., 2000. Cross Cult Research 34, 135-151]. The participants were 18 male and 14 female Japanese, and 11 male and 21 female Euro-Americans. There was a significant effect of sex: female participants considered pain behaviors more acceptable than male participants. There was a significant effect of culture: compared to both male and female Japanese, Euro-American participants rated pain behaviors in both sexes to be more acceptable. There was also a significant effect of referent gender: for both sexes in both cultures, pain behaviors in women were rated as more acceptable than in men. Furthermore, a significant interaction was found between referent gender and sex of the participant: Male and female participants of both cultures were equally accepting of pain behaviors in women, but male participants were less accepting of pain behaviors in men than in women. There also was a significant interaction between referent gender and culture of the participant: Japanese participants considered pain behavior in both genders to be less acceptable than did Americans. The results are explained in terms of cultural traditions and social roles, and have clear implications for clinical treatment and diagnosis.

[Oral morphine administration for children's traumatic pain]

OBJECTIVES

To study the compliance of prescription, the efficacity and the adverse events of oral morphine used in the pediatric emergency department (ED) in traumatic pains.

METHOD

This prospective study was conducted in the ED from october 2002 to september 2003. Children aged six months to 16 years with a visual analogic scale (VAS) score higher than 70 or with a traumatic member deformation received oral morphine (0,5 mg/kg). Pain was assessed every 30 minutes using two scales: behavioral observation by the faces scale and objective pain scale (OPS) for children less than five years, behavioral observation by the faces scale and self-report by VAS for children older than five years. The compliance of prescription, the pain scores and the adverse events were studied.

RESULTS

Ninety-one children received oral morphine and seventy-four children were studied. Seventy per cent of prescriptions were in accordance with the recommendations. For patients younger than five years a rapid decrease of pain was observed in thirty minutes. The pain's reduction was respectively 79 and 84% with faces scale and OPS when they left ED. For children older than five years, pain's reduction was more important and more rapid when pain assessment was made by nurses than when it was self-reported in the first hour (pain reduction 58,2 and 36,1%). When leaving, pain reduction was the same with the two different assessments. No major adverse event was noted.

CONCLUSION

Use of oral morphine in ED is simple, with a few numbers of adverse events. None was severe. Efficiency is correct after 30 to 60 minutes.

An audit of post-operative nausea and vomiting, following cardiac surgery: scope of the problem

Post-operative nausea and vomiting is a major problem for patients following cardiac surgery. The literature in this area identifies that there are a number of individual patient and post-operative factors which increase the risk of post-operative nausea and vomiting, including female gender, non-smoker, age, use of opioids, pain and anxiety. An audit involving 200 patients, who had undergone cardiac surgery was implemented to assess/evaluate the incidence of nausea and vomiting for this patient group. Data collected included information relating to nausea and vomiting, pain, consumption of morphine and other individual patient variables. The results suggest that nausea and vomiting, is experienced by a large number of patients after cardiac surgery (67%), with the majority suffering on the first day after surgery. The duration of nausea and vomiting for most is short, but for a significant number (7%) it can last up to one-quarter of their initial post-operative course. The paper discusses key implications for practice arising from this project.

Gender differences in drug effects: implications for anesthesiologists

BACKGROUND

The gender aspect in pharmacokinetics and pharmacodynamics of anesthetics has attracted little attention. Knowledge of previous work is required to decide if gender-based differences in clinical practice is justified, and to determine the need for research.

METHODS

Basis for this paper was obtained by Medline searches using the key words 'human' and 'gender' or 'sex,' combined with individual drug names. The reference lists of these papers were further checked for other relevant studies.

RESULTS

Females have 20-30% greater sensitivity to the muscle relaxant effects of vecuronium, pancuronium and rocuronium. When rapid onset of or short duration of action is very important, gender-modified dosing may be considered. Males are more sensitive than females to propofol. It may therefore be necessary to decrease the propofol dose by 30-40% in males compared with females in order to achieve similar recovery times. Females are more sensitive than males to opioid receptor agonists, as shown for morphine as well as for a number of kappa (OP2) receptor agonists. On this basis, males will be expected to require 30-40% higher doses of opioid analgesics than females to achieve similar pain relief. On the other hand, females may experience respiratory depression and other adverse effects more easily if they are given the same doses as males.

CONCLUSION

These examples illustrate that gender should be taken into account as a factor that may be predictive for the dosage of several anesthetic drugs. Moreover, there is an obvious need for more research in this area in order to further optimize drug treatment in anesthesia.

Perioperative management of complex skull base surgery: the anesthesiologist's point of view

The anesthetic management of complex skull base surgical procedures provides unique problems and concerns for the neuroanesthesiologist. Positioning to access the skull base could put the patient at risk for peripheral nerve injury and some of the positions may increase the risk for air emboli. In addition, tumor pathology and involvement with vital structures could increase the chances for substantive blood loss, destruction of associated nerves or vessels, and may require temporary occlusion of the carotid artery necessitating intraoperative neuroprotection. Neurophysiological monitors may also be used to safeguard nerve function and anesthetic techniques must be adjusted to accommodate their use. Finally, postoperative morbidity may be affected by surgical approach to the skull base and the anesthesiologist should be aware of which approach may produce a greater incidence of pain, nausea, and vomiting in the postoperative period.

The authors discuss the anesthetic concerns and management for complex cranial base surgery. Different approaches will be discussed and comparisons of perioperative parameters between these approaches will be made with data provided by retrospective chart review of more than 600 skull base procedures performed at the authors' institution over the last 10 years. This information should help guide decision making concerning anesthetic management for these skull base procedures.

Gender and pain upon movement are associated with the requirements for postoperative patient-controlled iv analgesia: a prospective survey of 2,298 Chinese patients

PURPOSE

To investigate prospectively the influence of patient characteristics upon, and the association of postoperative measurements with, the requirements for postoperative morphine and the assessment of resting pain and pain upon movement in Chinese patients.

METHODS

From January 1998 to December 1999, patients receiving patient-controlled iv morphine subsequent to general anesthesia and surgery at our institute (Kaohsiung Veterans General Hospital), were enrolled in the study. Demographic data (such as gender, age, weight, height and education level) and postoperative measurements, including pain scores at rest or during movement, sedation scores and morphine consumption, were recorded.

RESULTS

In total 2,298 patients were recruited. Females consumed significantly less morphine via patient-controlled analgesia (PCA) in the first three postoperative days than was the case for males (P <0.05). Gender was the strongest predictor for postoperative morphine requirements. Postoperative pain upon movement was another effective predictor for morphine requirement (P <0.05). Age, body height, body weight, education and operation sites were not associated with morphine consumption.

CONCLUSION

Gender and postoperative pain upon movement are the major factors influencing morphine requirement for patient-controlled iv morphine analgesia during the first three postoperative days in Chinese patients.

Concerns and misconceptions about pain among Hong Kong Chinese patients with cancer

It is estimated that approximately 50% of patients with cancer experience pain, and this percentage increases to 80% in patients with terminal cancer. Misconceptions and concerns of patients with cancer regarding the use of opioid analgesics have been identified as one of the major barriers to achieving optimal pain control. Misconceptions and concerns regarding addiction and tolerance to opioid analgesics and patients' desire to be "good" have been reported in the United States. The aim of this survey was to determine if similar misconceptions and concerns exist in Hong Kong Chinese patients with cancer. The results indicate that Hong Kong Chinese patients have the same concerns regarding the use of opioid analgesics. The respondents' fatalistic beliefs are a major hindrance to optimizing pain control, with 79% indicating that pain is an inevitable aspect of hospitalization because they believe that cancer pain cannot be relieved by medications. Fear of addiction was a major concern for 52% of the respondents, and about the same number of respondents believed that opioid analgesics should be administered only as a last resort. Regarding a desire to be "good," more patients reported that they would prefer to disturb nurses rather than physicians. It is desirable that culturally specific education programs be provided to dispel patient misconceptions and concerns regarding the use of opioid analgesics.

Data collection by acute pain services in Australia and New Zealand

Forty-three Acute Pain Service units in Australia and New Zealand were surveyed regarding data they collected on their daily rounds. The survey sought to determine what data each unit actually collected and what they considered to be a set of data that would be an acceptable minimal standard for the purpose of audit. The scoring or scaling mechanisms that were used in auditing the various parameters were also ascertained in an attempt to derive a consistent means of comparing data from the various Acute Pain Service groups. The Acute Pain Special Interest Group is currently developing suggestions for a standard data set and associated scoring mechanisms in line with the results of this survey.

Prevention of postoperative nausea and vomiting in gynaecological laparotomies: a comparison of tropisetron and ondansetron

In a randomized, double-blind study, the antiemetic efficacy of a single bolus of tropisetron 5 mg (group T, 37 patients), ondansetron 4 mg (group O, 39 patients) or saline (group C, 45 patients) given at induction was compared in a homogeneous group of 121 patients undergoing gynaecological laparotomy and receiving postoperative patient-controlled intravenous morphine for 24 to 48 hours. Fewer group T and group O patients developed severe nausea compared to group C (P < 0.01, log rank test in Kaplan-Meier analysis). Group T patients also had lower nausea scores than group O at 8 to 16h (P < 0.05). The overall incidences of severe nausea in groups T, O, and C were 5.4%, 17.9%, and 44.4% respectively (P < 0.001, group T vs group C; P < 0.05 group O vs group C). In conclusion, the 5-hydroxytryptamine 3 receptor antagonists tropisetron and ondansetron were superior to placebo in preventing PONV.

Incident reporting in acute pain management

Incident reporting is an effective tool for continuous quality improvement in clinical practice. A prospective study on voluntary incident reporting in pain management was conducted at a major teaching hospital in Hong Kong. Over a 12-month period, 53 incidents were reported in 1275 patients who received pain relief treatments which were supervised by the acute pain service. The majority of the incidents were first detected by the pain team. The most common incidents involved delivery circuits, delivery pump and drug administration. A large proportion (81.4%) of the incidents were thought to be preventable. Human factors were involved in 41.9% of the patients reported, most commonly associated with unfamiliar technique/inexperience, inattention and inadequate communication. Four patients developed major morbidity of which two were attributed to inadequate analgesia, while three others had major physiological changes without morbidity. Strategies have been formulated to prevent further occurrence of these incidents. We propose that incident reporting is a potentially useful tool in identifying and preventing adverse events in postoperative pain management.