Current understanding of the mixed pain concept: a brief narrative review

Despite having been referenced in the literature for over a decade, the term "mixed pain" has never been formally defined. The strict binary classification of pain as being either purely neuropathic or nociceptive once left a good proportion of patients unclassified; even the recent adoption of "nociplastic pain" in the IASP Terminology leaves out patients who present clinically with a substantial overlap of nociceptive and neuropathic symptoms. For these patients, the term "mixed pain" is increasingly recognized and accepted by clinicians. Thus, an independent group of international multidisciplinary clinicians convened a series of informal discussions to consolidate knowledge and articulate all that is known (or, more accurately, thought to be known) and all that is not known about mixed pain. To inform the group's discussions, a Medline search for the Medical Subject Heading "mixed pain" was performed via PubMed. The search strategy encompassed clinical trial articles and reviews from January 1990 to the present. Clinically relevant articles were selected and reviewed. This paper summarizes the group's consensus on several key aspects of the mixed pain concept, to serve as a foundation for future attempts at generating a mechanistic and/or clinical definition of mixed pain. A definition would have important implications for the development of recommendations or guidelines for diagnosis and treatment of mixed pain.

Comparing etoricoxib and celecoxib for preemptive analgesia for acute postoperative pain in patients undergoing arthroscopic anterior cruciate ligament reconstruction: a randomized controlled trial

Background

The efficacy of selective cox-2 inhibitors in postoperative pain reduction were usually compared with conventional non-selective conventional NSAIDs or other types of medicine. Previous studies also used selective cox-2 inhibitors as single postoperative dose, in continued mode, or in combination with other modalities. The purpose of this study was to compare analgesic efficacy of single preoperative administration of etoricoxib versus celecoxib for post-operative pain relief after arthroscopic anterior cruciate ligament reconstruction.

Methods

One hundred and two patients diagnosed as anterior cruciate ligament injury were randomized into 3 groups using opaque envelope. Both patients and surgeon were blinded to the allocation. All of the patients were operated by one orthopaedic surgeon under regional anesthesia. Each group was given either etoricoxib 120 mg., celecoxib 400 mg., or placebo 1 hour prior to operative incision. Post-operative pain intensity, time to first dose of analgesic requirement and numbers of analgesic used for pain control and adverse events were recorded periodically to 48 hours after surgery. We analyzed the data according to intention to treat principle.

Results

Among 102 patients, 35 were in etoricoxib, 35 in celecoxib and 32 in placebo group. The mean age of the patients was 30 years and most of the injury came from sports injury. There were no significant differences in all demographic characteristics among groups. The etoricoxib group had significantly less pain intensity than the other two groups at recovery room and up to 8 hours period but no significance difference in all other evaluation point, while celecoxib showed no significantly difference from placebo at any time points. The time to first dose of analgesic medication, amount of analgesic used, patient's satisfaction with pain control and incidence of adverse events were also no significantly difference among three groups.

Conclusions

Etoricoxib is more effective than celecoxib and placebo for using as preemptive analgesia for acute postoperative pain control in patients underwent arthroscopic anterior cruciate ligament reconstruction.

Trial registration number

NCT01017380

Comparing parecoxib and ketorolac as preemptive analgesia in patients undergoing posterior lumbar spinal fusion: a prospective randomized double-blinded placebo-controlled trial

Background

Poor postoperative pain control is frequently associated with complications and delayed discharge from a hospital. Preemptive analgesia is one of the methods suggested for reducing postoperative pain. Opioids are effective for pain control, but there known addictive properties make physicians cautious about using them. Parecoxib and ketorolac are potent non-opioid NSAIDs that are attractive alternative drugs to opioids to avoid opioid-related side effects. However, there are no good head-to-head comparisons between these two drugs in the aspect of preemptive analgesic effects in lumbar spinal fusion surgery. This study aimed to compare the efficacy in terms of postoperative pain control and safety of parecoxib with ketorolac as preemptive analgesia in posterior lumbar spinal fusion patients.

Methods

A prospective, double-blinded randomized controlled trial was carried out in patients undergoing posterior lumbar spinal fusion, who were randomized into 3 groups (n = 32). Parecoxib, ketorolac or a placebo was given to each patient via injection around 30 minutes prior to incision. The efficacy of postoperative pain control was assessed by a verbal numerical rating score (0–10). And various postoperative things were monitored for analysis, such as total opioid consumption, complications, and estimated blood loss.

Results

Both the ketorolac and parecoxib groups showed significantly better early postoperative pain reduction at the postanesthesia care unit (PACU) than the control group (p < 0.05). There were no differences between the pain scores of ketorolac and parecoxib at any time points. Complications and bleeding were not significantly different between all three groups.

Conclusions

Preemptive analgesia using both ketorolac and parecoxib showed a significantly better early postoperative pain control in the PACU than the control group in patients undergoing lumbar spinal fusion.

Trial registration

ClinicalTrials.gov NCT01859585. Registered 15 May 2013.

Tramadol: a valuable treatment for pain in Southeast Asian countries

Background

The supply of controlled drugs is limited in the Far East, despite the prevalence of health disorders that warrant their prescription. Reasons for this include strict regulatory frameworks, limited financial resources, lack of appropriate training amongst the medical profession and fear of addiction in both general practitioners and the wider population. Consequently, the weak opioid tramadol has become the analgesic most frequently used in the region to treat moderate to severe pain.

Methods

To obtain a clearer picture of the current role and clinical use of tramadol in Southeast Asia, pain specialists from 7 countries in the region were invited to participate in a survey, using a questionnaire to gather information about their individual use and experience of this analgesic.

Results

Fifteen completed questionnaires were returned and the responses analyzed. Tramadol is used to manage acute and chronic pain caused by a wide range of conditions. Almost all the specialists treat moderate cancer pain with tramadol, and every one considers it to be significant or highly significant in the treatment of moderate to severe non-cancer pain. The reasons for choosing tramadol include efficacy, safety and tolerability, ready availability, reasonable cost, multiple formulations and patient compliance. Its safety profile makes tramadol particularly appropriate for use in elderly patients, outpatients, and for long-term treatment. The respondents strongly agreed that tighter regulation of tramadol would reduce its medical availability and adversely affect the quality of pain management. In some countries, there would no longer be any appropriate medication for cancer pain or the long-term treatment of chronic pain.

Conclusions

In Southeast Asia, tramadol plays an important part in the pharmacological management of moderate to severe pain, and may be the only available treatment option. If it were to become a controlled substance, the standard of pain management in the region would decline.

Premedication with oral paracetamol for reduction of propofol injection pain: a randomized placebo-controlled trial

Background

To compare the effect of premedication with 2 different doses of oral paracetamol to prevent pain at propofol intravenous injection.

Methods

We conducted a double-blind randomized controlled trial in which patients scheduled for induction of general anesthesia with intravenous propofol received either a placebo, 500 mg or 1000 mg of oral paracetamol (P500 and P1000, respectively) 1 h prior to induction. Two mg/kg of propofol was injected at a rate of 600 ml/hr. After 1/4 of the full dose had been injected, the syringe pump was paused, and patients were asked to rate pain at the injection site using a verbal numerical rating score (VNRS) from 0 to 10.

Results

Three hundred and twenty-four patients were included. Pain intensity was lower in both P500 and P1000 groups (median VNRS [interquartile range] = 2 [0–3] and 4 [2–5], respectively) than in the placebo group (8 [7–10]; P < 0.001)*. The rate of pain was lower in the P1000 group (70.4%) than in both the P500 and the placebo group (86.1 and 99.1%, respectively; P < 0.001)*. The respective rates of mild (VNRS 1–3), moderate (VNRS 4–6) and severe pain (VNRS 7–10) were 47.2, 23.2 and 0% in the P1000 group, 28.7, 50 and 7.4% in the P500 group, and 0, 22.2 and 76.9% in the placebo group (P < 0.001* for between group comparisons). Tolerance was similar in the 3 groups.

Conclusions

A premedication with oral paracetamol can dose-dependently reduce pain at propofol intravenous injection. To avoid this common uncomfortable concern for the patients, this well-tolerated, available and cheap treatment appears as an option to be implemented in the current practice.

Trial registration

TCTR20150224002. Prospectively registered on 24 February 2015.

Attitudes of Medical Students Regarding Cancer Pain Management: Comparison Between Pre- and Post-Lecture Test Findings

BACKGROUND

Medical practitioners' attitudes have a significant impact on quality of care for cancer pain patients. This study was conducted to determine if being given a lecture concerning cancer pain and its management could improve the attitudes of medical students.

MATERIALS AND METHODS

A comparative study was conducted in 126 fifth-year medical students. Each student completed a pretest consisting of 3 questions about attitudes toward the optimal use of analgesics and 5 questions about attitudes toward prescribing opioids. Then they were given a 1.5-hour lecture, immediately following which they completed a post-test with the same questions.

RESULTS

Analysis with either comparison between groups or by matching, the post-test showed significantly more positive attitudes (p<0.05) of the medical students in all 3 questions about optimal use of analgesics and 4 out of 5 questions about prescription of opioids. The post-test results showed significantly more negative attitudes concerning the most appropriate stage for patients with severe pain to receive maximal doses of analgesics.

CONCLUSIONS

Conservative attitudes, especially concerns about addiction, have been associated with a reluctance in many physicians to prescribe opioids. This study found that cancer pain education can help to improve medical student attitudes. However, fear of addiction and tolerance was still evident so emphasis of this particular issue during a lecture is essential. Providing appropriate information by means of a lecture can improve the attitudes of medical students regarding cancer pain management. However, more information should be given to lessen fear of addiction and tolerance.

Cancer Pain and its Management: A Survey on Interns’ Knowledge, Attitudes and Barriers

Objective

We conducted this study to evaluate the knowledge and attitudes of interns regarding cancer pain and its management.

Materials and methods

This study included 116 interns recently graduated from the Faculty of Medicine, Prince of Songkla University. They provided their demographic characteristics and completed a questionnaire in regards to their knowledge and attitudes about cancer pain and its management.

Results

Data were obtained from 116 interns. The majority of interns did not hesitate to provide maximal doses of analgesics for patients in severe pain when the prognosis was poor. A significant number favored to prescribe pethidine more than morphine and thought that pethidine caused less harmful effects in long-term use. Most respondents agreed or strongly agreed that they would prescribe opioids carefully to avoid tolerance and addiction. They considered that barriers to effective pain management were inadequate knowledge, inadequate pain assessment and lack of time to attend patients’ requirements.

Conclusion

The interns demonstrated positive attitudes toward cancer pain and its management, principally on opioid usage. However, a significant number of them had misconceptions in terms of knowledge for prescribing opioids. To provide better cancer pain management, attention must be given to improving the curriculum and integrating it into clinical practice.

The Effectiveness of an Evidence-Based Pain Management Program on Pain Intensity and Chest Rehabilitation Improvement Among Chest Trauma Patients in a Thai Hospital

BACKGROUND

Pain after thoracic injury has further profound impacts on patients resulting in increased length of hospital stay and hospital care cost, and decreased quality of life. Utilization of the cutting-edge evidence on pain management that fits with the individual care context is therefore important.

AIM

To examine the effects of an evidenced-based pain management program on the worst pain intensity and lung vital capacity among acutely ill hospitalized chest trauma patients.

DESIGN

A two-group repeated measures design.

SETTINGS

trauma unit, a university hospital in southern Thailand.

PARTICIPANTS/SUBJECTS

42 chest trauma patients.

METHODS

The study population included 42 chest trauma patients admitted to the trauma unit. Twenty-one eligible chest trauma patients were consecutively assigned into intervention and control groups. The impacts of the intervention on the level of the worst pain intensity and lung vital capacity were measured before implementation of the program and throughout the first 5 days of admission.

RESULTS

The study found a significant reduction in the worst pain intensity and an increase in the lung vital capacity among chest trauma patients in the intervention group compared with the control group (p < .05).

CONCLUSIONS

Use of a pain management program can be an effective, inexpensive, and low-risk intervention for the improvement of pain management and chest rehabilitation among chest trauma patients.

Is ABO Blood Group a Predictive Factor for the Amount of Opioid Consumption in the First 24 Hours After Cesarean Section?

Background

Cesarean section is the most common major surgery performed globally. Blood group O has been found as a factor affecting pain severity after cesarean section. We aimed to evaluate the predictive factors, including ABO blood group, for the amount of opioid consumption (measured as milligrams of morphine equivalent [MME]) within the first 24 hrs after cesarean section.

Methods

This retrospective study was done in 1530 pregnant women who had a cesarean section under the same regimen of spinal anesthesia (2.2 mL of 0.5% hyperbaric bupivacaine and morphine 0.2 mg). All were prescribed regular paracetamol and ibuprofen for postoperative pain control. Univariate and multinomial regression analyses were performed to identify the predictive factors for opioid consumption in the first 24 hrs postoperatively.

Results

About 2/5 of them (43.3%) received 0 mg MME, while 25.6%, 23.7% and 7.4% received 1–5, 6–10 and >10 mg MME, respectively. The majority have blood group O (40.6%), while 23.4%, 28% and 8% have blood group A, B and AB, respectively. After univariate and multinomial regression analyses, operation time, opioid consumption in PACU, maximum VNRS within the first 24 hrs and consumption of both paracetamol and ibuprofen were identified as predictive factors for postoperative opioid consumption. ABO blood group exhibited no correlation for opioid requirement postoperatively.

Conclusion

ABO blood group is not a predictive factor for opioid requirement within the first 24 hrs following cesarean section. Duration of operation, opioid given in PACU, maximum VNRS on ward and consumption of both paracetamol and ibuprofen have been found to be predictive factors for postcesarean opioid requirement.

A prospective observational study to investigate the relationship between local anesthetic infiltration pain before spinal anesthesia and acute and chronic postsurgical pain in women undergoing elective cesarean delivery

BACKGROUND

Cesarean delivery is one of the most common procedures performed worldwide. We conducted this prospective cohort study to evaluate the association between local anesthetic infiltration (LAI) pain prior to spinal anesthesia and pain and morphine consumption within 24 h after cesarean delivery (primary outcomes). A secondary objective was to assess the association between LAI pain and pain at one month postoperatively.

METHODS

Recruitment of 216 eligible women scheduled for elective cesarean delivery. Local infiltration before spinal anesthesia was performed using a 24-gauge needle and 3 mL 2% plain lidocaine. All subjects received 2.2 mL 0.5% hyperbaric bupivacaine with 200 µg morphine for spinal anesthesia. A 0-10 verbal numerical rating scale was used to assess LAI pain severity, and subsequent pain at 24 h, 1, 3 and 12 months.

RESULTS

We found a moderate correlation between LAI pain intensity and severity of acute pain at rest (rho=0.56, P <0.001) and with movement (rho=0.58, P <0.001) and a weak correlation with morphine consumption (rho=0.17, P=0.01) within 24 h postoperatively. We also found a positive correlation between LAI pain and the severity of persistent wound pain at rest (rho=0.30, P <0.001) and with movement (rho=0.52, P <0.001) at 1 month. The incidence of wound pain at 1, 3 and 12 months postoperatively was 37.1%, 7.0% and 1.4%, respectively.

CONCLUSIONS

Pain from LAI prior to spinal anesthesia is significantly associated with subsequent postoperative pain both acutely and at one month in women scheduled for elective cesarean delivery under spinal anesthesia.

Anesthetic techniques and complications in patients with hepatocellular carcinoma undergoing percutaneous ethanol injection

AIM

The aim of this study was to analyze anesthetic techniques and complications found in patients with hepatocellular carcinoma (HCC) who have undergone percutaneous ethanol injection (PEI).

METHODS

A retrospective study was performed on 67 patients with HCC who underwent 120 sessions of ultrasound-guided PEI between January 2004 and April 2006.

RESULTS

The mean age of the patients was 56.4 (25-77) years. Males accounted for the majority of the patients (75%). The ASA classifications were from ASA class I (2.5%), class II (82.5%), and class III (15%). Premedication with benzodiazepines was given to 68.3% of the patients. In 81.7% of the procedures, the patients received total intravenous anesthesia with 13.3%, 4.2%, and 0.8% undergoing general anesthesia with either an endotracheal tube, general anesthesia with mask, or monitored anesthesia care, respectively. Most (95.8%) patients were given propofol. Thiopental and ketamine (1.7% each) were used as an induction agent. In only 0.8% of the sessions did the patient receive morphine as an intraprocedural analgesic, while 99.2% of the sessions received fentanyl. Isoflurane was delivered to all of the patients receiving general anesthesia. Bradycardia, hypotension, bradycardia plus hypotension and hypotension plus hypoxemia occurred in 0.8%, 6%, 0.8% and 0.8% of the sessions, respectively. A single patient (1.5% of the patients or 0.8% of the sessions) had cardiovascular collapse during the procedure. The mean duration of anesthesia was 34.7 (10-105) min and the patients were observed in a recovery room for a mean duration of 51.7 (0-175) min. The majority of the recovery room admissions (89.2%) did not have any complications. A minority of the cases (9.2%) received fentanyl in the recovery room as a means of pain management.

CONCLUSION

Various kinds of anesthesia are suitable for patients with HCC scheduled for ultrasound-guided PEI. Although PEI is not commonly associated with serious complications, it is not entirely risk-free and careful monitoring and prompt resuscitation are essential for the safety of the patients as the procedure is performed in an interventional radiology suite, which is considered to be a remote area.

Cost-Utility Analysis of Radiofrequency Ablation Among Facet Joint-Related Chronic Low Back Pain Patients in Thailand

BACKGROUND

Radiofrequency ablation (RFA) is a common secondary treatment recommended for facet joint-related chronic low back pain (CLBP). However, Thailand still lacks sufficient evidence of RFA's cost-effectiveness to support the decision to fund it.

OBJECTIVE

To conduct a comparative economic evaluation of RFA and conservative treatment for CLBP patients over 16-month and 28-month time horizons in Thailand.

STUDY DESIGN

A full economic evaluation encompassing measurements of both health utilities and health costs.

SETTING

Data were collected from 3 university hospitals in Bangkok, Thailand: King Chulalongkorn Memorial Hospital, Siriraj Hospital, and Ramathibodi Hospital.

METHODS

The cost-utility analysis, which used the Markov model, was developed according to the Thai health technology assessment guidelines and compared RFA and the best supportive care from the societal perspective. In the study, the population consisted of patients who had endured low back pain for more than 3 months despite receiving conservative treatment. The results were presented as an incremental cost-effective ratio (ICER) in Thai Baht (THB)/quality-adjusted life year (QALY). Scenario and sensitivity analyses were conducted.

RESULTS

RFA was not cost-effective in Thailand when compared to conservative treatment, with a cost-effectiveness (CE) ratio of I$13,652 at all time horizons. The ICER of RFA was I$99,267 and I$52,380/QALY for the 16- and 28-month time horizons, respectively. In a scenario analysis in which RFA was repeated at 28 months and followed up to 52 months, the ICER was reduced to I$43,451. One-way sensitivity analysis showed that the ICER was most sensitive to the changes in utility parameters, the cost of RFA, and opportunity cost in the no-pain state.

LIMITATIONS

The study uses primary data to derive the utility value and determine the costs. However, the limitation includes a relatively small sample size and a short follow-up time for parameter inputs.

CONCLUSION

This study, the first economic evaluation of RFA for CLBP in Asia, showed that RFA was not cost-effective in Thailand. Price negotiation is recommended to make the intervention more cost-effective before it is included in the benefit package.

Pain related articles published in Thailand in the last 20 years

BACKGROUND

The Thai Association for the Study of Pain was established 20 years ago with the aim of educating the members and health care providers for pain management and pain research.

OBJECTIVE

Evaluate the progression of pain research by literature survey on Thai journals, since the beginning of TASP MATERIAL AND METHOD: Pain related original articles, except for the abstracts, proceedings, case reports, and review articles, published in eight Thai journals between 1990 and 2009 were searched

RESULTS

The number of pain related articles was 233. The number of articles slowly but gradually increased during 1990 to 2002, drastically increased during 2004 and 2005, and then slightly decreased until 2009. About 75% of the papers were published in Thai language except for those published in one journal that has been published in English. The most common content of articles was related to the acute pain (75%) contributed by anesthesiologists.

CONCLUSION

Pain research has been significantly increasing since the TASP was founded, especially in the last 10 years. The most common area of research is in the field of acute pain. The majority of the articles were published in Thai language.

Expectations, experiences and attitudes of orthopedic patients undergoing arthroscopic cruciate ligament reconstruction toward postoperative pain and its management

OBJECTIVE

To evaluate expectations, experiences, and attitudes of orthopedic patients undergoing arthroscopic cruciate ligament reconstruction in terms of postoperative pain and management.

MATERIAL AND METHOD

This prospective study involved 115 patients. Preoperatively, patients completed a preoperative questionnaire regarding expectations toward postoperative pain and management. Postoperatively, they completed a postoperative questionnaire regarding exact pain experiences and attitudes in relation to their pain and management.

RESULTS

Almost all expected (95.6%) and experienced (98.3%) pain. The median values of maximum and average pain measured by a verbal numerical rating score were 7.7 and 5.6, respectively. Approximately 3/5 reported marked and maximum relief from analgesics received Only one patient was not satisfied with pain management while the rest were satisfied in varying degrees. A large proportion showed incorrect conceptions concerning postoperative pain and management.

CONCLUSION

Postoperative pain management is still an area for improvement. Misunderstandings of patients should be explored and corrected as they can pose a barrier for effective pain relief Pain management should begin with preoperative explanations and advice followed by good care intraoperatively and postoperatively.

Measuring pain intensity in older patients: a comparison of five scales

BACKGROUND AND AIMS

Pain is common in older individuals. In order to understand and treat pain in this group, reliable and valid measures are needed. This study aimed to evaluate: (1) the validity, utility, incorrect response rates and preference rates of 5 pain rating scales in older individuals; and (2) the associations between age, education level, and cognitive function and both (a) incorrect response and (b) preference rates.

METHODS

Two hundred and one orthopedic clinic outpatients ≥ 65 years old were asked to rate their current pain, and least, average, and worst pain intensity in the past week using 5 scales: Verbal Numerical Rating Scale (VNRS), Faces Pain Scale - Revised (FPS-R), Verbal Rating Scale (VRS), Numerical Rating Scale (NRS), and Visual Analogue Scale (VAS). Participants were also asked to indicate scale preference. We computed the associations between each measure and a factor score representing the shared variance among the scales, the incorrect response and scale preference rates, and the associations between incorrect response and preference rates and age, education level, and cognitive function. The incorrect responses included being unable to respond, providing more than one response, responses outside a range, providing range answers rather than fixed answers, and responses indicating 'least > average,' 'least > worst,' and 'average > worst'.

RESULTS

The findings support validity of all 5 scales in older individuals who are able to use all measures. The VNRS had the lowest (2%) and the VAS had the highest (6%) incorrect response rates. The NRS was the most (35%) and the VAS was the least (5%) preferred. Age was associated with the incorrect response rates of the VRS and VAS, such that older individuals were less likely to use these scales correctly. Education level was associated with the incorrect response rates of the FPS-R, NRS and VAS, such that those with less education were less likely to use these measures correctly. Cognitive function was not significantly associated with incorrect response rates. Age, education level and cognitive function were not significantly associated with scale preference.

CONCLUSIONS

Although all five scales are valid, the VNRS evidences the best overall utility in this sample of older individuals with pain. The NRS or FPS-R would be fine alternatives if it is not practical or feasible to use the VNRS.

Pain Management in Surgical Intensive Care Units: A Multi-Center Prospective Observational Study (THAI-SICU Study)

OBJECTIVE

This study is a part of the multi-center Thai university-based Surgical Intensive Care Unit Study (THAI-SICU Study). It aimed to evaluate the patterns of pain management in patients admitted to surgical intensive care units.

MATERIAL AND METHOD

Case record forms (CRFs) were created by the working group. Data regarding pain management in the ICUs were documented on the daily record form. These included types of analgesics used (opioids and non-opioids), routes of administration (oral, intravenous, intramuscular, epidural and intrathecal) and methods of administration (continuous infusion, regular intermittent, as needed, patient-controlled analgesia and patient-controlled epidural analgesia).

RESULTS

Data were gathered from 4,652 patients. The majority of the patients received analgesics (85.2%). The main stay analgesics were morphine (52.3%) and fentanyl (27%). Analgesics were frequently administered via the intravenous route (76.5%) on an as needed basis (48.6%).

CONCLUSION

Analgesics were commonly given to patients in the surgical intensive care units. The analgesics of choice were strong opioids, and the most preferred route and method of administration was the intravenous route and the as needed basis, respectively.

Myoclonic movements following induction of anesthesia with propofol: a case report

OBJECTIVE

To report a case of myoclonic movements during an induction of anesthesia using propofol. Abnormal movements resulting from propofol are uncommon but there have been a number of such cases since propofol was introduced.

CLINICAL FEATURES

An 1-year-old boy with a diagnosis of obstructive sleep apnea was scheduled to undergo adenotonsillectomy. He demonstrated myoclonic movements during anesthetic induction using propofol. He was then given isoflurane and his airway was secured with an endotracheal tube after full muscle relaxation by succinylcholine. The anesthetic maintenance was uneventful as was the emergence. The patient recovered smoothly without neurological deficit.

CONCLUSION

Propofol, an intravenous anesthetic, with strong evidence of anticonvulsant property, could, in susceptible patients, under certain conditions, act as a proconvulsant, and should, thus, be avoided or cautiously used in some patients.

ABO blood group is not a predictive factor for the amount of early opioid consumption in postanesthesia care unit: a prospective cohort study in 3,316 patients

Background

Immediate postoperative pain in the postanesthesia care unit (PACU) is common. Titration of opioid is the most popular strategy for controlling early postoperative pain. ABO blood group has been found to be associated with pain perception. We aimed to find the factors including ABO blood group for predicting the amount of opioid requirement in PACU.

Methods

This prospective cohort study was performed in 3316 patients who underwent various kinds of anesthetic techniques and received immediate postoperative care in PACU. Preoperative, intraoperative and PACU data were collected. A directed acyclic graph (DAG) representing the hypothesized causal pathways of preoperative, intraoperative and PACU data were compiled prior to conducting multinomial logistic regression analysis. Statistical significance in all models was defined as a P-value < 0.05.

Results

Female sex, body mass index, preoperative use of gabapentin, preoperative anxiety score, anesthetic techniques, type of operation, amount of consumed intraoperative opioids, intraoperative use of paracetamol, parecoxib and ondansetron, duration of anesthesia and surgery, amount of blood loss, pain upon PACU arrival, use of paracetamol and parecoxib in PACU were found to be factors influencing amount of opioid consumption in PACU. ABO blood group was not associated with early postoperative opioid requirement.

Conclusions

A significant number of factors are related to amount of opioid requirement in PACU. Some factors can be adjusted to provide better pain relief in early postoperative period. However, ABO blood group is not identified to be a predictive factor for early postoperative opioid consumption in PACU.

Improvement in Validity and Reliability of Airway Assessment Using Ultrasonography by Novice Personnel: A Learning Cohort Study

PURPOSE

To assess improvements in the validity and reliability of novices' skills in performing ultrasonography for airway assessment.

PATIENTS AND METHODS

A learning cohort study was conducted with 20 anesthesiology residents and 10 volunteers in the Department of Anesthesiology, Faculty of Medicine, Prince of Songkla University. The four parameters of airway assessment were soft tissue thickness at the level of 1) hyoid bone (STT-HY), 2) true vocal cords (STT-VC), 3) thyroid isthmus (STT-TI), and 4) suprasternal notch (STT-SN). The magnitude of discrepancies between the residents' and experienced anesthesiologists' measurements was evaluated over the sequence of measurements in the 10 volunteers.

RESULTS

The mean ultrasonic measurements of STT-HY by the experienced anesthesiologists and residents were significantly different (11.09 ± 3.14 mm vs 8.53 ± 3.02 mm, respectively; P = 0.008), whereas measurements of STT-VC, STT-TI, and STT-SN were not (7.18 ± 1.70 vs 7.14 ± 1.93, P = 0.32; 7.81 ± 2.14 vs 7.73 ± 2.19, P = 0.62; and 11.32 ± 3.33 vs 10.30 ± 3.02, P = 0.35, respectively). The mean discrepancy between the residents' and experienced anesthesiologists' measurements was close to zero throughout the sequence of measurements of STT-TI and STT-VC. However, the residents' measurements of STT-HY and STT-SN were considerably lower than those of anesthesiologists. The range of discrepancies between residents and experienced anesthesiologists in each sequential measurement was wide for all measurements, particularly for the measurement values of STT-HY, and the standard deviation of the discrepancies did not decrease over the sequence of measurements.

CONCLUSION

Over the sequence of measurements for airway assessment in 10 volunteers by 20 residents in this learning trial, we found no evidence of improvement in measurement accuracy. Discrepancies between the residents' and anesthesiologists' measurements and the variability in discrepancy across residents were greatest in the measurement of STT-HY.

The analgesic efficacy of tramadol in ambulatory gynecological laparoscopic procedures: a randomized controlled trial

BACKGROUND

To evaluate the postoperative analgesic efficacy of intravenous tramadol 50 mg administered before anesthetic induction in patients undergoing ambulatory gynecological laparoscopic procedures.

METHODS

This was a double-blind randomized, controlled trial conducted in 150 patients. Pain intensity was measured using a verbal numerical rating score at 1, 2, 6, 12, and 24 h postoperatively and at discharge. Requirement of analgesics (fentanyl and paracetamol), effect of pain on sleep, activity limitation, side effects (headache, dizziness, drowsiness, nausea, vomiting, and dry mouth), global perceived analgesic efficacy, satisfaction, and preference for stronger analgesics were assessed in the first 24 h postoperatively.

RESULTS

There were no statistical differences between the tramadol group and the placebo group in terms of clinical data and pain intensity at any measured times. Recovery room data showed no statistical differences regarding number of patients requiring fentanyl, time to first fentanyl requirement, total fentanyl required, verbal numerical rating score before fentanyl administration, and incidence of nausea/vomiting and shivering. Post-discharge data showed that patients in the tramadol group required statistically less paracetamol (3.2 vs. 3.9 tablets, P = 0.04). There were no statistical differences regarding the number of patients requiring paracetamol, verbal numerical rating score before taking paracetamol, effect of pain on sleep and activity, global perceived analgesic efficacy, satisfaction, preference for stronger analgesics, and side effects.

CONCLUSION

Intravenous tramadol 50 mg given before anesthetic induction did not reduce pain intensity but was well tolerated. Although tramadol statistically reduced the paracetamol requirement in the first 24 h postoperatively, it did not seem to provide a significant clinical advantage.

Attitudes, beliefs, and expectations of gynecological patients toward postoperative pain and its managementt

OBJECTIVE

To examine the attitudes, beliefs, and expectations of gynecological patients regarding postoperative pain and management.

MATERIAL AND METHOD

A prospective study performed in 112 patients undergoing major gynecological surgery, using a preoperative questionnaire regarding expectations toward postoperative pain and management and a postoperative questionnaire regarding actual pain experience, attitudes, and beliefs about pain and management.

RESULTS

The majority expected (92%) and experienced (89%) postoperative pain at moderate to very severe levels. The median visual analog scales (VAS) of expected and maximum experienced pain were 6.4 and 6 6, respectively. Ninety-eight percent reported at least moderate pain relief from the analgesics administered. Ninety-two percent were satisfied with their pain management. A significant number held misconceptions about postoperative pain and its management.

CONCLUSION

Patients should be preoperatively advised regarding postoperative pain and management. Misunderstandings should be corrected to improve the quality and adequacy of postoperative pain management.

The anxiolytic effects of preoperative administration of pregabalin in comparison to diazepam and placebo

We aimed to evaluate the potential anxiolytic effects of premedication with pregabalin, compared with diazepam and placebo. We conducted this non-inferiority, double-blind, randomized controlled trial in ASA classification I-II patients aged 18-70 years, scheduled for elective surgery under general anesthesia. They were allocated to receive pregabalin (75 mg the night before surgery and 150 mg 2 h before surgery), diazepam (5 and 10 mg in the same manner) or placebo. Preoperative anxiety was evaluated using verbal numerical rating scale (VNRS) and Amsterdam Preoperative Anxiety and Information Scale (APAIS) before and after premedication. Sleep quality, sedation level, and adverse effects were assessed as secondary outcomes. A total of 231 patients were screened and 224 completed the trial. The mean change (95%CI) in anxiety scores from before to after medication in pregabalin, diazepam, and placebo groups for VNRS were - 0.87 (- 1.43, - 0.30), - 1.17 (- 1.74, - 0.60), and - 0.99 (- 1.56, - 0.41), and for APAIS were - 0.38 (- 1.04, 0.28), - 0.83 (- 1.49, - 0.16), and - 0.27 (- 0.95, 0.40). The difference in change for pregabalin versus diazepam was 0.30 (- 0.50, 1.11) for VNRS and 0.45 (- 0.49, 1.38) for APAIS, exceeding the limit of inferiority for APAIS of 1.3. Sleep quality was statistically different between pregabalin and placebo groups (p = 0.048). Sedation in pregabalin and diazepam groups were significantly higher than placebo group (p = 0.008). No significant differences of other side effects, except dry mouth was higher in placebo group compared with diazepam (p = 0.006). The study filed to provide evidence at non-inferiority of pregabalin compared to diazepam. Furthermore, premedication with either pregabalin or diazepam did not significantly reduce the preoperative anxiety in comparison to placebo, despite the fact that both resulted in higher levels of sedation. Clinicians should weigh the benefits and risks of premedication with these 2 drugs.Thai Clinical Trials Registry: TCTR20190424001 (24/04/2019) Registry URL: https://www.thaiclinicaltrials.org/ .

Efficacy of benzydamine hydrochloride dripping at endotracheal tube cuff for prevention of postoperative sore throat

BACKGROUND

Postoperative sore throat (POST) is a frequent consequence following ETT intubation, which may negatively affect the postoperative course and patient satisfaction. Benzydamine hydrochloride is a topically-applied non-steroidal anti-inflammatory drug (NSAID). The authors evaluated the analgesic effect of benzydamine hydrochloride dripping on the ETT cuff on POST.

MATERIAL AND METHOD

Eighty-six patients participated in this randomized controlled trial. They were assigned into either the benzydamine hydrochloride or the control group. The whole ETT cuff was dripped either with 3 ml (4.5 mg) of benzydamine hydrochloride or nothing five minutes prior to anesthesia induction. The incidence and severity of POST at 0, 2, 4, 6, 12 and 24 hours postoperatively were assessed. The potential adverse effects of benzydamine hydrochloride (throat numbness throat burning sensation, dry mouth, and thirst) were also evaluated.

RESULTS

Twenty-five patients (58.14%) in each group had POST (p-value = 1). The severity of POST (calculated from affected patients) in both groups at different time points was not significantly different. Patients in the benzydamine hydrochloride group did not have a higher incidence of adverse effects.

CONCLUSION

We found that dripping benzydamine hydrochloride on the ETT cuff neither reduced the incidence of POST nor increased the incidence of adverse effects in comparison with no intervention.