https://orcid.org/0000-0002-2224-5792
Figures
Abstract
Background
The COVID-19 pandemic has significantly affected healthcare, particularly surgical care. Although short-term effects on surgical outcomes have been examined, understanding of long-term postoperative prognosis and pain management in COVID-19 patients remains limited. This knowledge gap is critical as the pandemic evolves and the need for optimized postoperative care becomes increasingly important.
Objective
The primary objective of this study was to evaluate the impact of COVID-19 infection on postoperative outcomes and pain management in surgical patients. We aimed to assess surgical mortality, complication rates, and postoperative pain levels in COVID-19-positive patients relative to a closely matched control group.
Methods
We conducted a retrospective cohort study of COVID-19 patients admitted to the ICU following surgery. Data were collected on baseline characteristics, postoperative complications, mortality and pain scores. Univariate and multivariate linear regression models were used to evaluate the impact of COVID-19 infection on postoperative pain. Stratified and interaction analyses were additionally performed to examine the robustness of these associations across subgroups.
Results
Mortality rates and the incidence of sepsis were significantly higher in the COVID-19 cohort. Patients with COVID-19 also experienced longer duration of mechanical ventilation in the ICU and prolonged ICU stays. In the fully adjusted multivariate linear regression model, COVID-19 infection was positively associated with higher postoperative visual analog scale pain scores (β = 1.51; 95% CI: 1.03–1.98; p < 0.001), corresponding to an average increase of 1.51 units in postoperative pain. Stratified analysis largely corroborated these findings across subgroups.
Conclusions
Surgical intervention in patients with COVID-19 was associated with higher mortality and sepsis rates, longer ICU stays, and increased postoperative pain scores. These findings highlight the need for continued research to optimize surgical care and improve patient outcomes in the evolving post-pandemic era.
Citation: Hu Y-Z, Qin Z-L, Tang W, Hu Z-L, Luo R-Y (2026) Influence of COVID-19 on postoperative prognosis and pain management. PLoS One 21(3): e0344211. https://doi.org/10.1371/journal.pone.0344211
Editor: Eyüp Serhat Çalık, Ataturk University Faculty of Medicine, TÜRKIYE
Received: October 5, 2025; Accepted: February 17, 2026; Published: March 9, 2026
Copyright: © 2026 Hu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: Due to ethical and legal restrictions related to human participant privacy, the minimal data set underlying the findings of this study cannot be made publicly available. Data are available from the Institutional Review Board of The Second Xiangya Hospital of Central South University for researchers who meet the criteria for access to confidential data (contact: xy2gcphyb@163.com). The authors did not have any special access privileges that others would not have.
Funding: This work was funded by: Natural Science Foundation of Hunan Province (2024JJ5503) awarded to RL, Natural Science Foundation of Hunan Province (2023JJ10088) awarded to ZH, Health Commission of Hunan Province (W20243166) awarded to YH, Open Project of Guangxi Key Laboratory of reproductive health and birth defect prevention (GXWCH-ZDKF-2023-01) awarded to ZH, Natural Science Foundation of Changsha (kq2403082) awarded to RL, National Natural Science Foundation of China (82271379) awarded to ZH, Joint Foundation of Hunan University of Chinese Medicine (2024XYLH053) awarded to YH. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors declare no competing interests.
Introduction
The coronavirus disease 2019 (COVID-19) pandemic has placed significant strain on healthcare systems worldwide and has led to considerable economic losses [1]. Global adult mortality rates surged during the pandemic in 2020 and 2021, reversing the previously observed decline [2]. The primary clinical manifestations of COVID-19 include fever, dry cough, dyspnea, myalgia, fatigue, lymphopenia, and radiographic evidence of pneumonia [3]. For anesthesiologists, fever or pneumonia is considered a relative contraindication for elective surgery. A 2024 report in The Lancet indicated that COVID-19 was the leading cause of disability-adjusted life-years (DALYs) globally, followed by ischemic heart disease, neonatal disorders, and stroke [4]. Consequently, although the peak of the COVID-19 epidemic has subsided, the virus continues to impose a significant medical burden, and surgical patients infected with COVID-19 remain a clinical concern. However, with the establishment of standardized COVID-19 management protocols, routine preoperative testing is no longer universally performed. Thus, the effects of COVID-19 on surgical patients remain insufficiently understood.
Research has demonstrated that the risks associated with elective and emergency surgery in individuals infected with COVID-19 are significantly elevated [5]. One study reported higher surgical mortality and complication rates in patients with COVID-19 compared to those without the infection [6]. In a retrospective cohort study by Lei et al., involving 34 surgical patients with confirmed COVID-19, the postoperative mortality rate was 20.5% [3]. Understanding post-infection recovery is therefore essential for enhancing postoperative care, disease management, long-term rehabilitation, optimizing healthcare resources, and shaping public health strategies [7]. However, patients with mild COVID-19 did not demonstrate an elevated risk of adverse postoperative outcomes at any assessed time point, and vaccination was associated with a reduced likelihood of mortality and other complications [8]. In certain cases, surgery must still be performed without delay. Nonetheless, limited research has examined COVID-19 patients who require ICU admission postoperatively.
This retrospective cohort study compared COVID-19 patients admitted to the ICU with those treated by the same surgical team at the Second Xiangya Hospital of Central South University. The primary endpoint was to assess surgical mortality and complication rates in COVID-19-positive patients relative to a closely matched control group. The secondary endpoint was to analyze the impact and risk factors related to postoperative pain.
Methods
This study was approved by the Medical Ethics Committee of the Second Xiangya Hospital of Central South University (approval number: LYF20240197). Medical records were accessed between 8 October and 30 December 2024 for research purposes. The authors did not have access to any information that could identify individual participants during or after collection. As all participant identities were anonymized and there was no possibility of disclosing personal information, the requirement for written informed consent was waived by the institutional ethics committee. The date of first patient enrollment is December 1, 2022. Before patient enrollment, the study was prospectively registered at the Chinese Clinical Trial Register (ChiCTR2400089575, https://www.chictr.org.cn/showproj.html?proj=242638, Principal investigator: Ru-Yi Luo, registration date: 11 September 2024). This manuscript adheres to the applicable STROBE guidelines.
Study participants
This retrospective cohort study was conducted at the Second Xiangya Hospital of Central South University, China, between December 2022 and January 2023. The study enrolled COVID-19-positive patients and COVID-19-negative controls, all of whom were admitted to the ICU following surgical treatment. Diagnosis of COVID-19 was based on nucleic acid testing using RT-PCR assays of nasopharyngeal swabs, which served as the gold standard for SARS-CoV-2 infection. Patients under 18 years of age, those with missing age information, and those who underwent gynecological, obstetrical, or transplant surgeries were excluded. Additionally, none of the included patients were critically ill or required intubation prior to surgery; all were admitted to the ICU postoperatively for monitoring. Due to the pandemic, only urgent or semi-urgent procedures were performed during the study period, and elective surgeries were largely suspended. The exclusion of pregnancy-related non-obstetric surgeries and transplant recipients aligns with standard perioperative research practices, as these groups differ substantially in clinical management and risk profiles [9,10].
COVID-19-positive patients were matched in a 1:2 ratio to non-COVID-19 surgical ICU patients based on sex, age (within five years), and identical surgical pathology. Matching was performed according to COVID-19 testing results obtained within one week before or after surgery. Where possible, controls were selected from the same period; otherwise, the earliest eligible historical match was used. All patients were treated by the same medical team and received comparable care. A CONSORT-style flowchart summarizing patient selection and exclusion is provided in Fig 1.
Abbreviations: COVID-19, coronavirus disease 2019; ICU, Intensive Care Unit.
Study outcomes
The primary endpoint was to compare in-hospital surgical mortality and complication rates between COVID-19 patients and the closely matched control group. The secondary objective was to evaluate the impact of COVID-19 infection and identify risk factors associated with postoperative pain.
Covariates
The following data were recorded for all COVID-19-affected patients admitted to the ICU after surgical treatment and their matched controls: sex, age, BMI, comorbidities (diabetes and hypertension), American Society of Anesthesiologists (ASA) class, and surgery type.
The descriptive statistics included key intraoperative variables such as duration of anesthesia, operative duration, transfusion, postoperative outcomes, hospitalization costs, and pain scale. Data were also collected on sepsis, sequential organ failure assessment (SOFA) score, hospital mortality or discontinued treatment, length of ICU and hospital stay, ventilator duration in the ICU, and the postoperative pain intensity. Pain intensity was assessed using the Visual Analog Scale (VAS), in which patients marked their perceived pain level on a 10-cm horizontal line anchored by “no pain” (0) and “worse pain imaginable” (10).
Statistical analysis
The datasets included 156 patients, comprising 52 with COVID-19 (33.3%) and 104 closely matched controls (66.7%) across 17 variables. The Shapiro-Wilk test was conducted to assess whether continuous variables followed a normal distribution. Descriptive statistics were computed for the entire dataset, stratified by group (COVID-19 and Control) (Tables 1 and 2). The number of missing values was noted. The mean and standard deviation (SD) were reported for continuous variables with a normal distribution, and the Student's t-test was used for comparison. For continuous data that exhibited a skewed distribution, the median (interquartile range) and range (minimum-maximum) were presented, and the Mann-Whitney U test was employed for evaluation. Categorical or dichotomous variables were expressed as frequency or percentage, and comparisons were made using the Chi-square or Fisher’s exact test. Table 1 provides descriptive statistics on baseline characteristics used for matching, indicating that the matching was satisfactory for the reported features.
We calculated β coefficient and 95% confidence intervals (CI) through univariate and multivariate linear regression models to evaluate the association of COVID-19, treated as a categorical variable, with the VAS score for postoperative pain. Multiple imputation was performed to address the remaining missing data, with 30 imputed datasets created and analyzed collectively. All variables in the study were selected for model adjustments based on their statistical significance and clinical relevance. Model 1 was adjusted for sex, age and BMI. Model 2 included additional adjustments for diabetes and hypertension. Model 3 was further adjusted for intraoperative features, including type of surgery, ASA class, transfusion, ventilator duration in the ICU, anesthesia duration, and operative duration. Model 4 was adjusted for sepsis, SOFA score and hospital mortality or discontinued treatment. Model 5 was fully adjusted, similar to Model 4, with additional adjustments for postoperative ICU stay, postoperative hospital stay and hospitalization costs. Moreover, linear regression models were employed for interaction and subgroup analyses based on sex, age, and BMI.
All statistical analyses were conducted using R Statistical software (Version 4.2.2, The R Foundation) and the Free Statistics analysis platform (Version 1.9.2). A two-tailed P value <0.05 was considered statistically significant.
Results
Baseline characteristics of participants
The study included 52 patients diagnosed with COVID-19 out of 329 patients admitted to the ICU post-surgery, matched with 104 control subjects during the same study period from December 2022 to January 2023. Among these patients, the mean age was 56 years, and 105 individuals were male, constituting 67.3% of the sample (Table 1 and 2). Of the 52 COVID-19 patients, 19 (36.5%) contracted the virus within 7 days prior to surgery, while 33 (63.5%) were infected within 7 days following surgery (Fig 1). No significant differences were observed between the control and COVID-19 groups regarding sex, age, BMI, ASA class, comorbidities (diabetes and hypertension), or type of surgery (Table 1).
Surgical management and anesthetic considerations in patients with COVID-19
Among patients with COVID-19, 33 out of 52 (63.5%) underwent cardiothoracic procedures. The remaining patients underwent spinal (12 [11.5%]), oral and maxillofacial (4 [3.8%]), general (12 [11.5%]), and neurosurgery (10 [9.6%]) procedures (Table 1). The mean operative duration and anesthesia duration did not differ significantly between the two groups (Table 2). However, the transfusion rate in the COVID-19 group was significantly higher than in the control group (10.6% vs. 25.0%, p = 0.019, Table 2). Moreover, the median SOFA score was 1.0 (IQR 0.0–2.0) in the overall cohort, with a statistically significant difference between the control group [1.0 (0.0–2.0)] and the COVID‑19 group [2.0 (0.8–3.0)] (P = 0.042).
Death, complications, costs and postoperative pain in patients with COVID-19
Mortality rates were significantly higher in the COVID-19 cohort compared to the control group (5 patients [9.6%] vs. 0 patients [0%]; p = 0.004, Table 2). Among the five deceased patients in the COVID-19 group, causes of death included septic shock (n = 1), cardiac complications (n = 3), and disseminated intravascular coagulation (n = 1). In addition, the incidence of sepsis was markedly greater in the COVID-19 group than in the control group (Table 2). The COVID-19 cohort also exhibited a longer duration of mechanical ventilation and extended ICU stays compared to controls (Table 2). However, no statistically significant differences were observed in postoperative hospital stay or associated costs between the two groups.
Persistent pain is increasingly recognized as a significant manifestation of long COVID-19 [11,12]. Postoperative pain scores were compared between the COVID-19 and control groups, with the highest score within 7 days post-surgery selected for analysis. VAS scores were significantly higher in the COVID-19 group than in the control group (p < 0.001, Table 2), indicating that patients with perioperative COVID-19 infection experienced more severe acute postoperative pain.
Associations between COVID-19 and VAS for pain
We conducted univariate and multivariate linear regression analyses to explore risk factors associated with postoperative pain. The results of the univariate analysis are presented in Table 3. Univariate linear regression analysis revealed that factors such as sex, age, BMI, diabetes, hypertension, type of surgery, ASA class, transfusion, ventilator duration in the ICU, anesthesia duration, operative duration, sepsis, SOFA score, postoperative ICU stay, hospital mortality or treatment discontinuation, and hospitalization costs were not significantly associated with the VAS score for postoperative pain. In contrast, COVID-19 infection and postoperative hospital stay were positively correlated with the VAS score.
Furthermore, we performed multivariable linear regression to assess the association between COVID-19 infection and the VAS score for postoperative pain, as shown in Table 4. The initial analysis using the unadjusted crude model indicated a significant positive association (β = 1.51; 95% CI: 1.08 ~ 1.94; p < 0.001). Covariates were then incrementally introduced across five adjusted models. The β values for the association between COVID-19 infection and VAS score in these adjusted models were 1.51 (95% CI: 1.08 ~ 1.94), 1.52 (95% CI: 1.09 ~ 1.96), 1.41 (95% CI: 0.96 ~ 1.86), 1.57 (95% CI: 1.10 ~ 2.03), and 1.51 (95% CI: 1.03 ~ 1.98). The P values in all five models were less than 0.001, indicating a consistent and statistically significant association.
To eliminate the influence of preoperative and postoperative COVID-19 infection on postoperative pain, we categorized the COVID-19 group into preoperative and postoperative infection subgroups. Multivariate linear regression analysis was performed on data from these two subgroups. The results revealed no statistically significant differences between them (S1 Table), suggesting that the timing of infection did not significantly affect the postoperative pain scores.
We further performed stratified and interaction analyses by sex, age, and BMI to determine whether the association between COVID-19 infection and VAS score for postoperative pain was consistent across different subgroups (Fig 2). The stratified analysis indicated that the results across all subgroups were consistent with the multivariate linear regression findings. No statistically significant interactions were detected in the stratified analyses, suggesting no effect modification.
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); COVID-19, coronavirus disease 2019; VAS, visual analog scale; y, years; 95% CI: 95% confidence intervals.
Discussion
Primary findings
Surgical procedures in patients with COVID-19 were associated with increased rates of blood transfusions, sepsis and hospital mortality, as well as higher SOFA score, longer durations of mechanical ventilation and extended stays in the ICU. Moreover, COVID-19 infection was linked to elevated postoperative pain scores. While the 1.51-unit increase in VAS score was statistically significant, its clinical significance—for example, its impact on functional recovery, opioid consumption, or patient-reported quality of life—requires further investigation in future studies specifically designed to assess these outcomes. Collectively, these findings highlight the need for tailored postoperative care and pain management strategies in this patient population.
Postoperative pulmonary complications have been reported in approximately 50% of patients with perioperative COVID-19 infection, significantly correlating with increased mortality rates [13]. Consequently, it is recommended to defer non-urgent surgical procedures and prioritize non-operative treatment options when feasible [13]. A Canadian cohort study reported a 30-day postoperative mortality rate of 15.9% among COVID-19 patients undergoing surgery [14]. Our observed mortality rate of 9.6%, although lower than early pandemic reports, remains substantially higher than in matched controls, underscoring a significant perioperative risk. This may reflect the characteristics of our ICU-admitted cohort, the influence of SARS-CoV-2 variants prevalent during late 2022, or the potential impact of prior vaccination and improved treatment protocols, which were not assessed in this study. Consistently, our research demonstrated that surgical patients with COVID-19 experienced higher incidences of blood transfusions, sepsis, mortality, and longer durations of mechanical ventilation while in the ICU, as well as extended ICU stays. These findings suggest that anesthesiologists and surgeons should enhance preoperative assessments and postoperative surveillance, optimize surgical timing, implement personalized treatment protocols, and adopt a multidisciplinary approach to perioperative care to reduce mortality and improve outcomes.
The COVID-19 pandemic has also been associated with new-onset chronic pain, particularly among patients requiring intensive support [11]. Headache is often an initial symptom and may correlate with a milder disease trajectory during the acute phase. The association between COVID-19 and increased postoperative pain observed in our study may be driven by several mechanisms. The systemic hyperinflammatory and pro-thrombotic state induced by COVID-19 may exacerbate surgical stress and impair tissue healing. In addition, SARS-CoV-2 may have neurotropic effects, potentially altering peripheral and central pain processing pathways and increasing postoperative pain sensitization. Despite increasing awareness of pain management as a critical aspect of care, limited literature addresses postoperative pain in COVID-19 patients. Pain is recognized as the fifth vital sign [15], and effective pain control is crucial for postoperative rehabilitation and enhanced recovery [16]. Our findings indicate that COVID-19 infection can increase postoperative pain by 1.51 units, independent of sex, age, and BMI.
Poorly managed postoperative pain can contribute to chronic pain development, with studies reporting that up to 40% of patients in UK pain clinics attributed their chronic pain to surgical or traumatic injuries [17]. Pain is also a risk factor for postoperative cognitive dysfunction (POCD), likely due to overlapping neural substrates for pain perception and cognitive control [18]. Additionally, increased postoperative pain can lead to pulmonary complications such as atelectasis and pneumonia due to restricted breathing and impaired coughing [19]. These complications can prolong hospitalization, increase readmission rates, and elevate healthcare resource utilization, thereby increasing economic burdens on patients and healthcare systems [20]. The elevated pain scores in COVID-19 patients highlight a critical area for intervention, as effective pain management may mitigate adverse health outcomes and reduce associated costs. Patients with COVID-19 should therefore exercise caution when undergoing surgical procedures.
Our findings also demonstrated that COVID-19 patients experienced higher rates of blood transfusion, sepsis, and hospital mortality, likely linked to the profound inflammatory and pro-thrombotic state induced by SARS-CoV-2 infection. COVID-19 is associated with coagulopathy, characterized by thrombotic and hemorrhagic complications, which may explain the increased transfusion requirements in our cohort [21,22]. The virus also induces lymphopenia and immune dysfunction, impairing the host's ability to combat secondary bacterial infections and predisposing patients to sepsis [23,24]. This immune dysregulation, together with surgical stress, likely contributes to elevated mortality. Our results align with existing literature identifying immune and coagulation dysfunction as key predictors of poor outcomes in hospitalized COVID-19 patients and establish perioperative COVID-19 as an independent risk factor for adverse events. These findings underscore the importance of enhance preoperative assessments and postoperative surveillance for these complications in COVID-19 patients.
In this study, five patients died postoperatively. One patient died of septic shock following surgery for a perforated sigmoid colon, another from low cardiac output syndrome after cardiac surgery, and a third, admitted with severe hemorrhagic shock, died due to disseminated intravascular coagulation (DIC). In another case, a patient with acute respiratory distress syndrome (ARDS) and multiple comorbidities had ventilator support withdrawn for financial reasons, leading to death. Finally, a polytrauma patient undergoing spinal surgery with a history of atrial fibrillation, coronary artery disease, and renal failure died from postoperative cardiac complications. All deceased patients had preexisting comorbidities and underwent emergency surgery for acute hemorrhage or intestinal perforation. Deaths were attributed to postoperative sepsis or exacerbation of underlying conditions.
Limitations
This study has several limitations that should be acknowledged. First, its retrospective, single-center design, conducted during a specific phase of the pandemic, may introduce selection and information biases and limits the generalizability of the findings to other settings, populations, or future SARS-CoV-2 variants. Second, the relatively small sample size of ICU-admitted surgical patients with COVID-19 restricts statistical power for detailed subgroup analyses and for examining potential dose-response relationships. This focused cohort also represents a more severe spectrum of illness, which may not be generalizable to all surgical patients with perioperative COVID-19 infection, particularly those with mild or asymptomatic disease. Third, despite rigorous matching, unmeasured or inconsistently documented variables—such as COVID-19 severity, viral load, duration of symptoms, specific respiratory parameters, vaccination status, SARS-CoV-2 variant, and comorbidities including malignancy or chronic immunosuppression—may lead to residual confounding. Fourth, postoperative pain assessment based on the peak VAS score within seven days may not fully capture temporal fluctuations or the modulating effects of analgesic regimens over time. Finally, as an observational study, it can establish associations but not causality. Future prospective, multi-center studies with larger cohorts and standardized data collection are needed to validate these findings and further elucidate the underlying mechanisms.
Conclusions
This study demonstrated that surgical patients with COVID-19 faced increased risks of blood transfusion, postoperative infection, mortality, prolonged mechanical ventilation in the ICU, and extended ICU stays, along with higher postoperative pain levels. Although causality cannot be inferred, the consistent associations observed across adjusted models reinforce these findings. These results emphasize the need for vigilant, individualized perioperative care for this vulnerable population. We recommend enhanced preoperative optimization, careful intraoperative management, and proactive multimodal analgesia for surgical patients with perioperative COVID-19. Future large-scale, prospective studies with detailed phenotyping are warranted to confirm these associations, elucidate the underlying mechanisms, and evaluate tailored perioperative care bundles aimed at mitigating these risks.
Supporting information
S1 Table. Multivariable linear regression analyses at multiple interpolation of Postoperative Pain.
https://doi.org/10.1371/journal.pone.0344211.s001
(DOCX)
References
- 1. Ochani R, Asad A, Yasmin F, Shaikh S, Khalid H, Batra S, et al. COVID-19 pandemic: from origins to outcomes. A comprehensive review of viral pathogenesis, clinical manifestations, diagnostic evaluation, and management. Infez Med. 2021;29(1):20–36. pmid:33664170
- 2. GBD 2021 Demographics Collaborators. Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950-2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021. Lancet. 2024;403(10440):1989–2056. pmid:38484753
- 3. Lei S, Jiang F, Su W, Chen C, Chen J, Mei W, et al. Clinical characteristics and outcomes of patients undergoing surgeries during the incubation period of COVID-19 infection. EClinicalMedicine. 2020;21:100331. pmid:32292899
- 4. GBD 2021 Diseases and Injuries Collaborators. Global incidence, prevalence, years lived with disability (YLDs), disability-adjusted life-years (DALYs), and healthy life expectancy (HALE) for 371 diseases and injuries in 204 countries and territories and 811 subnational locations, 1990-2021: a systematic analysis for the Global Burden of Disease Study 2021. Lancet. 2024;403(10440):2133–61. pmid:38642570
- 5. Minto T, Abdelrahman T, Jones L, Wheat J, Key T, Shivakumar N, et al. Safety of maintaining elective and emergency surgery during the COVID-19 pandemic with the introduction of a Protected Elective Surgical Unit (PESU): A cross-specialty evaluation of 30-day outcomes in 9,925 patients undergoing surgery in a University Health Board. Surg Open Sci. 2022;10:168–73. pmid:36211629
- 6. Doglietto F, Vezzoli M, Gheza F, Lussardi GL, Domenicucci M, Vecchiarelli L, et al. Factors Associated With Surgical Mortality and Complications Among Patients With and Without Coronavirus Disease 2019 (COVID-19) in Italy. JAMA Surg. 2020;155(8):691–702. pmid:32530453
- 7. Stone R, Scheib S. Advantages of, and Adaptations to, Enhanced Recovery Protocols for Perioperative Care during the COVID-19 Pandemic. J Minim Invasive Gynecol. 2021;28(3):481–9. pmid:33359742
- 8. Verhagen NB, SenthilKumar G, Jaraczewski T, Koerber NK, Merrill JR, Flitcroft MA, et al. Severity of Prior COVID-19 Infection is Associated with Postoperative Outcomes Following Major Inpatient Surgery. medRxiv. 2023. pmid:37131614
- 9. Zeleke ME, Chekol WB, Kasahun HG, Mekonnen ZA, Filatie TD, Melesse DY, et al. Perioperative management of surgical procedure during pregnancy: a systematic review. Ann Med Surg (Lond). 2024;86(6):3432–41. pmid:38846888
- 10. Palamuthusingam D, Kunarajah K, Pascoe EM, Johnson DW, Hawley CM, Fahim M. Postoperative outcomes of kidney transplant recipients undergoing non-transplant-related elective surgery: a systematic review and meta-analysis. BMC Nephrol. 2020;21(1):365. pmid:32843007
- 11. Shanthanna H, Nelson AM, Kissoon N, Narouze S. The COVID-19 pandemic and its consequences for chronic pain: a narrative review. Anaesthesia. 2022;77(9):1039–50. pmid:35848380
- 12. Alexander I. Electronic medical records for the orthopaedic practice. Clin Orthop Relat Res. 2007;457:114–9. pmid:17415063
- 13. COVIDSurg Collaborative. Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study. Lancet. 2020;396(10243):27–38. pmid:32479829
- 14. Carrier FM, Amzallag É, Lecluyse V, Côté G, Couture ÉJ, D’Aragon F, et al. Postoperative outcomes in surgical COVID-19 patients: a multicenter cohort study. BMC Anesthesiol. 2021;21(1):15. pmid:33435887
- 15. Lynch M. Pain as the fifth vital sign. J Intraven Nurs. 2001;24(2):85–94. pmid:11836838
- 16. Dieu A, Huynen P, Lavand’homme P, Beloeil H, Freys SM, Pogatzki-Zahn EM, et al. Pain management after open liver resection: Procedure-Specific Postoperative Pain Management (PROSPECT) recommendations. Reg Anesth Pain Med. 2021;46(5):433–45. pmid:33436442
- 17. Chen Y-YK, Boden KA, Schreiber KL. The role of regional anaesthesia and multimodal analgesia in the prevention of chronic postoperative pain: a narrative review. Anaesthesia. 2021;76 Suppl 1(Suppl 1):8–17. pmid:33426669
- 18. Li W-X, Luo R-Y, Chen C, Li X, Ao J-S, Liu Y, et al. Effects of propofol, dexmedetomidine, and midazolam on postoperative cognitive dysfunction in elderly patients: a randomized controlled preliminary trial. Chin Med J (Engl). 2019;132(4):437–45. pmid:30707179
- 19. Abdel Jalil R, Abdallah FA, Obeid Z, Abou Chaar MK, Harb AK, Shannies TB, et al. Maintaining quality of life after major lung resection for carcinoid tumor. J Cardiothorac Surg. 2023;18(1):330. pmid:37964297
- 20. Buck C, Keweloh C, Bouras A, Simoes EJ. Efficacy of Short Message Service Text Messaging Interventions for Postoperative Pain Management: Systematic Review. JMIR Mhealth Uhealth. 2021;9(6):e20199. pmid:34132646
- 21. Gando S, Wada T. Thromboplasminflammation in COVID-19 Coagulopathy: Three Viewpoints for Diagnostic and Therapeutic Strategies. Front Immunol. 2021;12:649122. pmid:34177896
- 22. Gando S, Wada T. Pathomechanisms Underlying Hypoxemia in Two COVID-19-Associated Acute Respiratory Distress Syndrome Phenotypes: Insights From Thrombosis and Hemostasis. Shock. 2022;57(1):1–6. pmid:34172612
- 23. Savirón-Cornudella R, Villalba A, Esteban LM, Tajada M, Rodríguez-Solanilla B, Andeyro-Garcia M, et al. Screening of severe acute respiratory syndrome coronavirus-2 infection during labor and delivery using polymerase chain reaction and immunoglobulin testing. Life Sci. 2021;271:119200. pmid:33577855
- 24. Mertz C, Glowinski R, Cohen SH, Mertz S, Ye F, Hall MW, et al. Severe Acute Respiratory Syndrome Coronavirus 2 RNAemia and Clinical Outcomes in Children With Coronavirus Disease 2019. J Infect Dis. 2022;225(2):208–13. pmid:34618885