Logistic Regression Is Non-Inferior to the Response Surface Model in Patient Response Prediction of Video-Assisted Thoracoscopic Surgery.

Response surface models (RSMs) are a new trend in modern anesthesia. RSMs have demonstrated significant applicability in the field of anesthesia. However, the comparative analysis between RSMs and logistic regression (LR) in different surgeries remains relatively limited in the current literature. We hypothesized that using a total intravenous anesthesia (TIVA) technique with the response surface model (RSM) and logistic regression (LR) would predict the emergence from anesthesia in patients undergoing video-assisted thoracotomy surgery (VATS). This study aimed to prove that LR, like the RSM, can be used to improve patient safety and achieve enhanced recovery after surgery (ERAS). This was a prospective, observational study with data reanalysis. Twenty-nine patients (American Society of Anesthesiologists (ASA) class II and III) who underwent VATS for elective pulmonary or mediastinal surgery under TIVA were enrolled. We monitored the emergence from anesthesia, and the precise time point of regained response (RR) was noted. The influence of varying concentrations was examined and incorporated into both the RSM and LR. The receiver operating characteristic (ROC) curve area for Greco and LR models was 0.979 (confidence interval: 0.987 to 0.990) and 0.989 (confidence interval: 0.989 to 0.990), respectively. The two models had no significant differences in predicting the probability of regaining response. In conclusion, the LR model was effective and can be applied to patients undergoing VATS or other procedures of similar modalities. Furthermore, the RSM is significantly more sophisticated and has an accuracy similar to that of the LR model; however, the LR model is more accessible. Therefore, the LR model is a simpler tool for predicting arousal in patients undergoing VATS under TIVA with Remifentanil and Propofol.

Dose-response relationship between epidural bupivacaine dose and mortality risk after surgical resection of nonsmall-cell lung cancer.

BACKGROUND: Preclinical studies have shown that local anesthetics may modify the growth and invasion of cancer cells. However, few clinical studies have evaluated their impact on cancer outcomes after tumor resection. METHODS: In this single-center cohort study, patients who underwent surgical resection of stage IA through IIIB nonsmall-cell lung cancer and used patient-controlled epidural analgesia from 2005 to 2015 were recruited and followed until May 2017. Data of the epidural bupivacaine dose for each patient were obtained from infusion pump machines. Proportional hazards regression models were used to analyze the associations between bupivacaine dose with postoperative cancer recurrence and all-cause mortality. RESULTS: A total of 464 patients were analyzed. Among these patients, the mean bupivacaine dose was 352 mg (± standard deviation 74 mg). After adjusting for important clinical and pathological covariates, a significant dose-response relationship was observed between epidural bupivacaine dose and all-cause mortality (adjusted hazard ratio: 1.008, 95% confidence interval: 1.001-1.016, p = 0.029). The association between bupivacaine dose and cancer recurrence were not significant (adjusted hazard ratio: 1.000, 95% confidence interval: 0.997-1.002, p = 0.771). Age, sex, body mass index, mean daily maximum pain score, and pathological perineural infiltration were independently associated with bupivacaine dose. CONCLUSION: A dose-dependent association was found between epidural bupivacaine dose and long-term mortality among patients following surgical resection of nonsmall-cell lung cancer. Our findings do not support the hypothetical anticancer benefits of local anesthetics. More studies are needed to elucidate the role of local anesthetics in cancer treatment.

Group-based trajectory analysis of acute pain after spine surgery and risk factors for rebound pain.

Background: This retrospective study was designed to explore the types of postoperative pain trajectories and their associated factors after spine surgery. Materials and methods: This study was conducted in a single medical center, and patients undergoing spine surgery with intravenous patient-controlled analgesia (IVPCA) for postoperative pain control between 2016 and 2018 were included in the analysis. Maximal pain scores were recorded daily in the first postoperative week, and group-based trajectory analysis was used to classify the variations in pain intensity over time and investigate predictors of rebound pain after the end of IVPCA. The relationships between the postoperative pain trajectories and the amount of morphine consumption or length of hospital stay (LOS) after surgery were also evaluated. Results: A total of 3761 pain scores among 547 patients were included in the analyses and two major patterns of postoperative pain trajectories were identified: Group 1 with mild pain trajectory (87.39%) and Group 2 with rebound pain trajectory (12.61%). The identified risk factors of the rebound pain trajectory were age less than 65 years (odds ratio [OR]: 1.89; 95% CI: 1.12-3.20), female sex (OR: 2.28; 95% CI: 1.24-4.19), and moderate to severe pain noted immediately after surgery (OR: 3.44; 95% CI: 1.65-7.15). Group 2 also tended to have more morphine consumption (p < 0.001) and a longer length of hospital stay (p < 0.001) than Group 1. Conclusion: The group-based trajectory analysis of postoperative pain provides insight into the patterns of pain resolution and helps to identify unusual courses. More aggressive pain management should be considered in patients with a higher risk for rebound pain after the end of IVPCA for spine surgery.

Influential Factors and Personalized Prediction Model of Acute Pain Trajectories after Surgery for Renal Cell Carcinoma.

Background: Renal cell carcinoma (RCC) is the most common neoplasm in kidneys, and surgical resection remains the mainstay treatment. Few studies have investigated how the postoperative pain changes over time and what has affected its trajectory. This study aimed to characterize the variations in postoperative pain over time and investigate associated factors after RCC surgery. Methods: This retrospective study was conducted in a single medical center in Taiwan, where maximal pain scores in a numeric rating scale were recorded daily in the first five postoperative days (PODs) after RCC surgery. Latent curve models were developed, using two latent variables, intercept and slope, which represented the baseline pain and rate of pain resolution. These models explain the variations in postoperative pain scores over time. A predictive model for postoperative pain trajectories was also constructed. Results: There were 861 patients with 3850 pain observations included in the analysis. Latent curve analysis identified that female patients and those with advanced cancer (stage III and IV) tended to have increased baseline pain scores (p = 0.028 and 0.012, respectively). Furthermore, patients over 60 years, without PCA use (both p < 0.001), and with more surgical blood loss (p = 0.001) tended to have slower pain resolution. The final predictive model fit the collected data acceptably (RMSEA = 0.06, CFI = 0.95). Conclusion: Latent curve analysis identified influential factors of acute pain trajectories after RCC surgery. This study may also help elucidate the complex relationships between the variations in pain intensity over time and their determinants, and guide personalized pain management after surgery for RCC.

Fire safety study on high-flow nasal oxygen in shared-airway surgeries with diathermy and laser: simulation based on a physical model.

High-flow nasal oxygen (HFNO) has been used in "tubeless" shared-airway surgeries but whether HFNO increased the fire hazard is yet to be examined. We used a physical model for simulation to explore fire safety through a series of ignition trials. An HFNO device was attached to a 3D-printed nose with nostrils connected to a degutted raw chicken. The HFNO device was set at twenty combinations of different oxygen concentration and gas flow rate. An electrocautery and diode laser were applied separately to a fat cube in the cavity of the chicken. Ten 30 s trials of continuous energy source application were conducted. An additional trial of continuous energy application was conducted if no ignition was observed for all the ten trials. A total of eight short flashes were observed in one hundred electrocautery tests; however, no continuous fire was observed among them. There were thirty-six events of ignition in one hundred trials with laser, twelve of which turned into violent self-sustained fires. The factors found to be related to a significantly increased chance of ignition included laser application, lower gas flow, and higher FiO2. The native tissue and smoke can ignite and turn into violent self-sustained fires under HFNO and continuous laser strikes, even in the absence of combustible materials. The results suggest that airway surgeries must be performed safely with HFNO if only a short intermittent laser is used in low FiO2.

Group-based trajectory analysis of postoperative pain in epidural analgesia for video-assisted thoracoscopic surgery and risk factors of rebound pain.

BACKGROUND: The current study aimed to investigate the patterns of postoperative pain trajectories over time and their associated risk factors in patients receiving video-assisted thoracoscopic surgery (VATS) and epidural analgesia (EA) for non-small cell lung cancer (NSCLC). METHODS: This retrospective study was conducted at a tertiary medical center and included patients undergoing VATS for stage I NSCLC between 2011 and 2015. Maximal pain intensity was recorded daily during the first postoperative week. Group-based trajectory analysis was performed to categorize variations in pain scores over time. Associations between pain trajectory classification and amount of EA administered and length of hospital stay (LOS) after surgery were also evaluated. RESULTS: A total of 635 patients with 4647 pain scores were included in the analysis, and 2 postoperative pain trajectory groups were identified: group 1, mild pain trajectory (78%); and group 2, rebound pain trajectory (22%). Risk factors for rebound pain trajectory were a surgical time longer than 3 hours (odds ratio [OR], 1.97; 95% CI, 1.27-3.07), female sex (OR, 1.62; 95% CI, 1.04-2.53), and higher pain score on postoperative day 0 (OR, 1.21; 95% CI, 1.08-1.36; linear effect). Although group 2 had a longer LOS (p < 0.001), they did not receive more EA than group 1 (p = 0.805). CONCLUSION: Surgical time, sex, and pain intensity after surgery were major determinants of rebound pain trajectory, and more aggressive pain control strategies should be considered in high-risk patients.

Perioperative Blood Transfusion Is Dose-Dependently Associated with Cancer Recurrence and Mortality after Head and Neck Cancer Surgery.

BACKGROUND: The association between perioperative blood transfusion and cancer prognosis in patients with head and neck cancer (HNC) receiving surgery remains controversial. METHODS: We designed a retrospective observational study of patients with HNC undergoing tumor resection surgery from 2014 to 2017 and followed them up until June 2020. An inverse probability of treatment weighting (IPTW) was applied to balance baseline patient characteristics in the exposed and unexposed groups. COX regression was used for the evaluation of tumor recurrence and overall survival. RESULTS: A total of 683 patients were included; 192 of them (28.1%) received perioperative packed RBC transfusion. Perioperative blood transfusion was significantly associated with HNC recurrence (IPTW adjusted HR: 1.37, 95% CI: 1.1-1.7, p = 0.006) and all-cause mortality (IPTW adjusted HR: 1.37, 95% CI: 1.07-1.74, p = 0.011). Otherwise, there was an increased association with cancer recurrence in a dose-dependent manner. CONCLUSION: Perioperative transfusion was associated with cancer recurrence and mortality after HNC tumor surgery.

Energy Achievement Rate Is an Independent Factor Associated with Intensive Care Unit Mortality in High-Nutritional-Risk Patients with Acute Respiratory Distress Syndrome Requiring Prolonged Prone Positioning Therapy.

Early enteral nutrition (EN) and a nutrition target >60% are recommended for patients in the intensive care unit (ICU), even for those with acute respiratory distress syndrome (ARDS). Prolonged prone positioning (PP) therapy (>48 h) is the rescue therapy of ARDS, but it may worsen the feeding status because it requires the heavy sedation and total paralysis of patients. Our previous studies demonstrated that energy achievement rate (EAR) >65% was a good prognostic factor in ICU. However, its impact on the mortality of patients with ARDS requiring prolonged PP therapy remains unclear. We retrospectively analyzed 79 patients with high nutritional risk (modified nutrition risk in the critically ill; mNUTRIC score ≥5); and identified factors associated with ICU mortality by using a Cox regression model. Through univariate analysis, mNUTRIC score, comorbid with malignancy, actual energy intake, and EAR (%) were associated with ICU mortality. By multivariate analysis, EAR (%) was a strong predictive factor of ICU mortality (HR: 0.19, 95% CI: 0.07-0.56). EAR >65% was associated with lower 14-day, 28-day, and ICU mortality after adjustment for confounding factors. We suggest early EN and increase EAR >65% may benefit patients with ARDS who required prolonged PP therapy.

Prognostic Factors to Predict ICU Mortality in Patients with Severe ARDS Who Received Early and Prolonged Prone Positioning Therapy.

Early and prolonged prone positioning (PP) therapy improve survival in advanced ARDS; however, the predictors of mortality remain unclear. The study aims to identify predictive factors correlated with mortality and build-up the prognostic score in patients with severe ARDS who received early and prolonged PP therapy. A total of 116 patients were enrolled in this retrospective cohort study. Univariate and multivariate regression models were used to estimate the odds ratio (OR) of mortality. Factors associated with mortality were assessed by Cox regression analysis and presented as the hazard ratio (HR) and 95% CI. In the multivariate regression model, renal replacement therapy (RRT; OR: 4.05, 1.54-10.67), malignant comorbidity (OR: 8.86, 2.22-35.41), and non-influenza-related ARDS (OR: 5.17, 1.16-23.16) were significantly associated with ICU mortality. Age, RRT, non-influenza-related ARDS, malignant comorbidity, and APACHE II score were included in a composite prone score, which demonstrated an area under the curve of 0.816 for predicting mortality risk. In multivariable Cox proportional hazard model, prone score more than 3 points was significantly associated with ICU mortality (HR: 2.13, 1.12-4.07, p = 0.021). We suggest prone score ≥3 points could be a good predictor for mortality in severe ARDS received PP therapy.

A comparison of prognostic performance of perioperative inflammation markers in surgical resection for hepatocellular carcinoma.

BACKGROUND: Systemic inflammation correlates closely with tumor invasion and may predict survival in cancer patients. We aimed to compare the prognostic value of various inflammation-based markers in patients with hepatocellular carcinoma. METHODS: We consecutively enrolled 1450 patients with primary hepatocellular carcinoma undergoing surgical resection at the medical center between 2005 and 2016 and assessed them through September 2018. Prognostic nutritional index, neutrophil-to-lymphocyte ratio, and platelet-to-lymphocyte ratio along with their perioperative dynamic changes were analyzed regarding their predictive ability of postoperative disease-free survival and overall survival. We calculated the adjusted hazard ratio (HR) and 95% CI of the association between inflammation-based markers and survival using multiple Cox proportional hazards models. Youden's index of receiver operating characteristics curves was used to determine optimal cut-off points. RESULTS: Prognostic nutritional index was an independent predictor for both disease-free survival (<50.87 vs ≥50.87, HR: 1.274, 95% CI, 1.071-1.517, p = 0.007) and overall survival (<46.65 vs ≥46.65, HR: 1.420, 95% CI, 1.096-1.842, p = 0.008). Besides, the relative change of neutrophil-to-lymphocyte ratio predicted overall survival (<277% vs ≥277%, HR: 1.634, 95% CI, 1.266-2.110, p < 0.001). Combination of both markers offered better prognostic performance for overall survival than either alone. Body mass index, liver cirrhosis, chronic kidney disease, and tumor diameter were significantly associated with both markers. CONCLUSION: Prognostic nutritional index and perioperative relative change of neutrophil-to-lymphocyte ratio independently predict postoperative survival in patients undergoing surgical resection of hepatocellular carcinoma. These results provided important evidence for risk stratification and individualized anti-cancer therapy.

Epidural analgesia does not impact recurrence or mortality in patients after rectal cancer resection.

The relationship between epidural analgesia and rectal cancer outcome is not fully clarified. We aimed to investigate the putative effect of epidural analgesia on the risks of recurrence and mortality after rectal tumour resection. In this monocentric cohort study, we consecutively enrolled patients with stage I-III rectal cancer who underwent tumour resection from 2005 to 2014. Patients received epidural analgesia or intravenous opioid-based analgesia for postoperative pain control. Primary endpoint was first cancer recurrence. Secondary endpoints were all-cause mortality and cancer-specific mortality. We collected 1282 patients in the inverse probability of treatment weighting analyses, and 237 (18.5%) used epidurals. Follow-up interval was median 46.1 months. Weighted Cox regression analysis showed the association between epidural analgesia and recurrence-free survival was non-significant (adjusted hazard ratio [HR] 0.941, 95% CI 0.791-1.119, p = 0.491). Similarly, the association between epidural analgesia and overall survival (HR 0.997, 95% CI 0.775-1.283, p = 0.984) or cancer-specific survival (HR 1.113, 95% CI 0.826-1.501, p = 0.482) was non-significant either. For sensitivity tests, quintile stratification and stepwise forward model selection analyses showed similar results. We did not find a significant association between epidural analgesia and risk of recurrence, all-cause mortality, or cancer-specific mortality in patients with rectal cancer undergoing tumour resection.

Association Between Epidural Analgesia and Cancer Recurrence or Survival After Surgery for Renal Cell Carcinoma: A Propensity Weighted Analysis.

Whether epidural anesthesia and analgesia (EA) is beneficial for postoperative cancer outcomes remains controversial and we conducted this historical cohort study to evaluate the association between EA and long-term outcomes following surgery for renal cell carcinoma (RCC). We collected patients receiving RCC surgery from 2011 to 2017 and followed up them until February 2020. Patient attributes, surgical factors and pathological features were gathered through electronic medical chart review. The association between EA and recurrence-free and overall survival after surgery was evaluated using Cox regression models with inverse probability of treatment weighting (IPTW) to balance the observed covariates. The median follow-up time for the 725 included patients was 50 months (interquartile range: 25.3-66.5) and 145 of them (20%) received perioperative EA. We demonstrated EA use was associated with better recurrence-free survival [IPTW adjusted hazard ratio (HR): 0.64, 95% confidence interval (CI): 0.49-0.83, p < 0.001] and overall survival [IPTW adjusted HR: 0.66, 95% CI: 0.49-0.89, p = 0.006] in patients receiving surgical resection for RCC. More prospective studies are needed to verify this connection between EA and superior cancer outcomes after RCC surgery.

A-qCPR risk score screening model for predicting 1-year mortality associated with hospice and palliative care in the emergency department.

BACKGROUND: Evaluating the need for palliative care and predicting its mortality play important roles in the emergency department. AIM: We developed a screening model for predicting 1-year mortality. DESIGN: A retrospective cohort study was conducted to identify risk factors associated with 1-year mortality. Our risk scores based on these significant risk factors were then developed. Its predictive validity performance was evaluated using area under receiving operating characteristic analysis and leave-one-out cross-validation. SETTING AND PARTICIPANTS: Patients aged 15 years or older were enrolled from June 2015 to May 2016 in the emergency department. RESULTS: We identified five independent risk factors, each of which was assigned a number of points proportional to its estimated regression coefficient: age (0.05 points per year), qSOFA ⩾ 2 (1), Cancer (4), Eastern Cooperative Oncology Group Performance Status score ⩾ 2 (2), and Do-Not-Resuscitate status (3). The sensitivity, specificity, positive predictive value, and negative predictive value of our screening tool given the cutoff larger than 3 points were 0.99 (0.98-0.99), 0.31 (0.29-0.32), 0.26 (0.24-0.27), and 0.99 (0.98-1.00), respectively. Those with screening scores larger than 9 points corresponding to 64.0% (60.0-67.9%) of 1-year mortality were prioritized for consultation and communication. The area under the receiving operating characteristic curves for the point system was 0.84 (0.83-0.85) for the cross-validation model. CONCLUSIONS: A-qCPR risk scores provide a good screening tool for assessing patient prognosis. Routine screening for end-of-life using this tool plays an important role in early and efficient physician-patient communications regarding hospice and palliative needs in the emergency department.

A comparison of inflammation markers for predicting oncological outcomes after surgical resection of non-small-cell lung cancer: a validated analysis of 2,066 patients.

Clinical and pathological predictors have proved to be insufficient in identifying high-risk patients who develop cancer recurrence after tumour resection. We aimed to compare the prognostic ability of various inflammation markers in patients undergoing surgical resection of lung cancer. We consecutively included 2,066 patients with stage I-III non-small-cell lung cancer undergoing surgical resection at the center between 2005 and 2015. We evaluated prognostic nutritional index, neutrophil-to-lymphocyte ratio, and platelet-to-lymphocyte ratio along with their perioperative changes. We conducted stepwise backward variable elimination and internal validation to compare the selected markers' predictive performance for postoperative recurrence-free survival and overall survival. Preoperative neutrophil-to-lymphocyte ratio independently predicts recurrence-free survival (HR: 1.267, 95% CI 1.064-1.509, p = 0.0079, on base-2 logarithmic scale) and overall survival (HR: 1.357, 95% CI 1.070-1.721, p = 0.0117, on base-2 logarithmic scale). The cut-off value is 2.3 for predicting both recurrence (sensitivity: 46.1% and specificity: 66.7%) and mortality (sensitivity: 84.2% and specificity: 40.4%). Advanced cancer stage, poor tumour differentiation, and presence of perineural infiltration were significantly correlated with higher preoperative neutrophil-to-lymphocyte ratio. We concluded that preoperative neutrophil-to-lymphocyte ratio is superior to prognostic nutritional index and platelet-to-lymphocyte ratio in predicting postoperative recurrence and mortality of patients undergoing surgical resection of non-small-cell lung cancer.

The association of non-small cell lung cancer recurrence with allogenic blood transfusion after surgical resection: A propensity score analysis of 1,803 patients.

BACKGROUND: Conflicting evidence underlies the controversial role of allogenic blood transfusion in recurrence of non-small cell lung cancer (NSCLC). Insufficient sample size and failure to measure effects of important confounders in previous studies contribute to the conflicting findings. To overcome these limitations, we applied robust statistics and weighted covariates in a large study cohort. METHODS: Cox regression analyses were used to estimate the recurrence and survival in patients with NSCLC disease stages I through III who were transfused for a haemoglobin level less than 8.0 g/dL within seven days after surgical resection. Inverse probability of treatment weighting (IPTW) was used to balance covariates in the sequential cohort of patients receiving an incremental amount of blood. We applied restricted cubic spline functions to characterise dose-response effects of transfusion amount on recurrence and mortality. RESULTS: A total of 209 (11.6%) of 1803 patients received transfusions. Over a median of 42 months after surgery (interquartile range 24.9-71.9), patients who received blood had a greater risk of early recurrence (IPTW-adjusted HR: 1.81, 95% CI: 1.59-2.06, P < 0.001) and all-cause mortality (IPTW-adjusted hazard ratio, HR: 2.38, 95% CI: 1.97-2.87, P < 0.001). A non-linear dose-response occurred between transfusion amount and recurrence or mortality. CONCLUSIONS: The greater risk of disease recurrence and early mortality after surgical resection in NSCLC patients who receive blood transfusion supports use of clinical strategies to reduce exposure. Further studies are needed to identify benchmarks to guide evidence-based practices.

Dynamic analysis of variations in postoperative pain trajectories over time in patients receiving epidural analgesia using latent curve models.

BACKGROUND: Although epidural analgesia (EA) provides reliable pain relief after major operations, few studies have explored how postoperative pain trajectories change over time in patients receiving EA and the associated factors. This study aimed to model the dynamic features of pain trajectories after surgery and investigate factors associated with their variations using latent curve analysis. METHODS: This retrospective study was conducted at a single medical center in Taiwan, and data were obtained from patients receiving perioperative EA by electronic chart review. Mean numeric rating pain scores were recorded daily in the first five postoperative days. Patient demographics, surgical sites, and infusion pump settings were also collected. Latent curve models using two latent variables, intercept and slope, were developed to explain the variations in postoperative pain scores over time. The influences of potential predictors of postoperative pain trajectories were further evaluated for the final model determination. RESULTS: Of the 1294 collected patients, the daily pain scores averaged 2.0 to 2.9 for different surgical sites. Among the nine significant factors influencing pain trajectories, chest and lower extremity surgery tended to induce less and more baseline pain, respectively, than those with abdomen surgery (both p < 0.001). In addition, male patients and those with a shorter anesthesia time had less baseline pain (p < 0.001 and p = 0.016, respectively). The older and lighter patients and those with chest surgery or American Society of Anesthesiologists class ≥ 3 tended to have milder decreasing trends in pain trajectories. A higher infusion rate was associated with an elevated baseline level and smoother decreasing trend in pain trajectory. The final model fit our data acceptably (root mean square error of approximation = 0.05, comparative fit index = 0.97). CONCLUSION: Latent curve analysis provided insights into the dynamic nature of variations in postoperative pain trajectories. Further studies investigating more factors associated with pain trajectories are warranted to elucidate the mechanisms behind the transitions of pain scores over time after surgery.

An investigation of the effect of patient-controlled analgesia on long-term quality of life after major surgery: A prospective cohort study.

BACKGROUND: Chronic pain is a common postoperative complication in patients undergoing major surgery and may significantly affect their quality of life (QOL). Whether patient-controlled analgesia (PCA) can reduce the risk of chronic postsurgical pain and promote long-term QOL is still unclear. METHODS: In this prospective cohort study, we followed up patients undergoing major surgery, recorded changes in their postoperative QOL over time using the World Health Organization Quality of Life-BREF (WHOQOL-BREF) questionnaire and chronic pain events, evaluated the long-term effects of distinct PCA techniques (intravenous, epidural, or none) on their QOL and risk of chronic pain, and explored relevant predictors. The patients' QOL and chronic pain events were collected preoperatively, 3, 6, and 12 months after surgery. Generalized linear mixed models were used to control for individual heterogeneity and adjust for potential confounding factors. RESULTS: We included 328 patients undergoing major surgery from September 22, 2015, to December 31, 2016, in this study. Multivariate regression models showed that patients using intravenous PCA had a better QOL in physical health (adjusted coefficient 3.7, 95% CI, 0.5-8.0) compared with those receiving non-PCA treatments. Distinct PCA techniques did not significantly affect QOL in psychological, social relationship, or environmental domains of the WHOQOL-BREF scale or the risk of chronic postsurgical pain. CONCLUSION: Patients using intravenous PCA had a better QOL in physical health over time after major surgery, which may have been due to factors other than pain-relieving effects.

Influential factors of postoperative pain trajectories in patients receiving intravenous patient-controlled analgesia: a single-centre cohort study in Taiwan.

OBJECTIVES: We aimed to investigate the factors associated with variations in postoperative pain trajectories over time in patients using intravenous patient-controlled analgesia (IV-PCA) for postoperative pain. DESIGN: Retrospective cohort study. SETTING: A single medical centre in Taiwan. PARTICIPANTS: Patients receiving IV-PCA after surgery. PRIMARY AND SECONDARY OUTCOME MEASURES: Primary outcome was the postoperative pain scores. RESULTS: A total of 3376 patients and 20 838 pain score observations were analysed using latent curve models. Female and longer anaesthesia time increased the baseline level of pain (p=0.004 and 0.003, respectively), but abdominal surgery and body weight decreased it (both p<0.001). Regarding the trend of pain resolution, lower abdominal surgery steepened the slope (p<0.001); older age, American Society of Anesthesiologists (ASA) class ≥3 and longer anaesthesia time tended to flatten the slope (p<0.001, =0.019 and <0.001, respectively). PCA settings did not affect the variations in postoperative pain trajectories. CONCLUSIONS: Patient demographics, ASA class, anaesthesia time and surgical sites worked together to affect postoperative pain trajectories in patients receiving IV-PCA. Latent curve models provided valuable information about the dynamic and complex relationships between the pain trajectories and their influential factors.