OBJECTIVE: To develop a method for identifying high-risk patients among septic populations requiring mechanical ventilation, and to conduct phenotypic analysis based on this method. METHODS: Data from four sources were utilized: the Medical Information Mart for Intensive Care (MIMIC-IV 2.0, MIMIC-III 1.4), the Philips eICU-Collaborative Research Database 2.0 (eICU-CRD 2.0), and the Anhui Medical University Second Affiliated Hospital dataset. The adult patients in intensive care unit (ICU) who met Sepsis-3 and received invasive mechanical ventilation (IMV) on the first day of first admission were enrolled. The MIMIC-IV dataset with the highest data integrity was divided into a training set and a test set at a 6:1 ratio, while the remaining datasets were served as validation sets. The demographic information, comorbidities, laboratory indicators, commonly used ICU scores, and treatment measures of patients were extracted. Clinical data collected within first day of ICU admission were used to calculate the sequential organ failure assessment (SOFA) score. K-means clustering was applied to cluster SOFA score components, and the sum of squared errors (SSE) and Davies-Bouldin index (DBI) were used to determine the optimal number of disease subtypes. For clustering results, normalized methods were employed to compare baseline characteristics by visualization, and Kaplan-Meier curves were used to analyze clinical outcomes across phenotypes. RESULTS: This study enrolled patients from MIMIC-IV dataset (n = 11 166), MIMIC-III dataset (n = 4 821), eICU-CRD dataset (n = 6 624), and a local dataset (n = 110), with the four datasets showing similar median ages and male proportions exceeding 50%; using 85% of the MIMIC-IV dataset as the training set, 15% as the test set, and the rest dataset as the validation set. K-means clustering based on the six-item SOFA score was performed to determine the optimal number of clusters as 3, and patients were finally classified into three phenotypes. In the training set, compared with the patients with phenotype II and phenotype III, those with phenotype I had the more severe circulatory and respiratory dysfunction, a higher proportion of vasoactive drug usage, more obvious metabolic acidosis and hypoxia, and a higher incidence of congestive heart failure. The patients with phenotype II was dominated by respiratory dysfunction with higher visceral injury. The patients with phenotype III had relatively stable organ function. The above characteristics were consistent in both the test and validation sets. Analysis of infection-related indicators showed that the patients with phenotype I had the highest SOFA score within 7 days after ICU admission, initial decreases and later increases in platelet count (PLT), and higher counts of neutrophils, lymphocytes, and monocytes as compared with those with phenotype II and phenotype III, their blood cultures had a higher positivity rates for Gram-positive bacteria, Gram-negative bacteria and fungi as compared with those with phenotype II and phenotype III. The Kaplan-Meier curve indicated that in the training, test, and validation sets, the 28-day cumulative mortality of patients with phenotype I was significantly higher than that of patients with phenotypes II and phenotype III. CONCLUSIONS Three distinct phenotypes in septic patients receiving IMV based on unsupervised machine learning is derived, among which phenotype I, characterized by cardiorespiratory failure, can be used for the early identification of high-risk patients in this population. Moreover, this population is more prone to bloodstream infections, posing a high risk and having a poor prognosis.
Humans ; Machine Learning ; Sepsis/therapy* ; Respiration, Artificial ; Intensive Care Units ; Organ Dysfunction Scores ; Male ; Female ; Middle Aged ; Adult

Objective:To investigate the carriage of the thalassemia gene in sperm donors in Chongqing,China by analyzing the thalas-semia screening and gene mutation types of sperm donors in Chongqing Human Sperm Bank(CHSB),and to provide a reference for thalassemia screening in sperm donors in Chongqing.Methods:Blood samples were collected from 488 sperm donors in CHSB(donors with all tests qualified during the quarantine)from December 2021 to August 2024.A complete blood count analysis was performed to measure the mean corpuscular volume(MCV)and mean corpuscular hemoglobin(MCH).Polymerase chain reaction(PCR)/agarose gel electrophoresis was used to detect deletional α-thalassemia mutations.PCR and DNA reverse dot blot hybridization were used to detect 3 common non-deletional α-thalassemia mutations and 17 common β-thalassemia mutations.The test results were then analyzed.Results:Among the 488 sperm donors aged 25.64±4.95 years,15(3.07％,all Han nationality)tested positive for thalassemia.This carriage rate was lower than that of the thalassemia population in Chongqing(9.24％).Among the 15 thalassemia carriers,13 had deletional α-gene mutations(-α3.7 genotype in 11 cases[73.33％],-α4.2 genotype in 1 case[6.67％],and-SEA genotype in 1 case[6.67％]),and 2 had non-deletional α-gene mutations(both with the WSM heterozygous mutation).There was only 1 case of abnor-mal MCV and MCH2 indicators among thalassemia carriers(screening positive rate was 6.67％).Conclusion:Thalassemia screening in sperm donors in CHSB reveals a low thalassemia carriage rate,reflecting geographic(predominantly Sichuan and Chongqing ori-gins)and demographic(healthy men of childbearing potential)characteristics.Given the significant impact of thalassemia on the off-spring conceived through sperm donation,it is recommended to conduct thalassemia gene screening among sperm donors in human sperm banks.

Objective:To explore the efficacy of free medial sural artery perforator flap transplantation in repairing electrical burn wounds on hands and feet.Methods:This study was a retrospective observational study. From November 2017 to September 2023, 21 male patients aged 28-51 years with electrical burns on hands and feet who met the inclusion criteria were admitted to Tongren Hospital of Wuhan University & Wuhan Third Hospital. There were 23 wounds, of which 14 were on the hand and 9 on the foot; 9 were associated with exposed tendon injury, 6 were associated with bone exposure or necrosis, and 8 were associated with joint injury. The wound area after debridement was 4.0 cm×2.5 cm-14.0 cm×10.0 cm. For 2 relatively wide wounds and 2 adjacent fingers/toes wounds, the lobulated flaps centered on 2 medial sural artery perforators were designed and incised for repair. For other wounds, medial sural artery perforator flaps were designed and incised. The flap area was 5.0 cm×3.0 cm-16.0 cm×11.0 cm. The arteriovenous vessels of flap were anastomosed end-to-end with the arteriovenous vessels of the recipient area; the cutaneous nerves of 10 flaps were anastomosed with the nerves in hand wound, and the sural nerve bundle was cut to repair one digital nerve defect. The donor site wound was closed with tension-relieving sutures. Postoperative flap survival and wound healing at donor site were recorded. During follow-up, subsequent flap revision was recorded, the texture and appearance of the flap, as well as the scarring and functional recovery of the donor area of the lower leg, were observed. At the last follow-up, the recovery of hand flap sensation was observed, the satisfaction of patients with the treatment effect of each operation was investigated by using Likert scale, the hand function of the affected hand in patients with hand wounds was evaluated by using the trial standards for evaluation of partial function of upper extremity by the Hand Surgery Society of Chinese Medical Association, and the weight-bearing walking ability of the affected foot in patients with foot wounds was evaluated by Holden walking ability grading.Results:There was a slight necrosis at the distal end of one flap after surgery, which healed after dressing change. All 23 flaps survived. The sutures of the two donor areas were poorly healed due to high local tension, and the second sutures were performed after debridement and drainage, and the healing was good. The wounds of the remaining 21 donor sites healed well. Follow-up of 6-26 months after surgery showed that 3 flaps were slightly bloated, and the appearance was improved after flap reconstruction; the other flaps did not undergo subsequent revision. All flaps were soft and similar to the surrounding tissue morphology. Linear scar remained in the donor site of the lower leg, and walking function was normal. At the last follow-up, the protective sensation of the hand flap was restored; the patients were very satisfied with the results of 21 surgeries and were relatively satisfied with the results of 2 surgeries. Among the 14 patients with hand wounds, the affected hand function was rated as excellent in 10 cases, very good in 3 cases, and acceptable in one case, and the weight-bearing walking ability of the affected foot in 7 patients with foot wounds was all rated as grade Ⅴ.Conclusions:The medial sural artery perforator flap has the advantages of reliable blood supply, appropriate thickness and smoothness, and can be lobulated or cut according to the shape of the wound. The flap demonstrates superior aesthetic and functional restoration in repairing electrical burn wounds on hands and feet, achieving high patient satisfaction with the surgical treatment effect.

Objective:To explore the efficacy of free medial sural artery perforator flap transplantation in repairing electrical burn wounds on hands and feet.Methods:This study was a retrospective observational study. From November 2017 to September 2023, 21 male patients aged 28-51 years with electrical burns on hands and feet who met the inclusion criteria were admitted to Tongren Hospital of Wuhan University & Wuhan Third Hospital. There were 23 wounds, of which 14 were on the hand and 9 on the foot; 9 were associated with exposed tendon injury, 6 were associated with bone exposure or necrosis, and 8 were associated with joint injury. The wound area after debridement was 4.0 cm×2.5 cm-14.0 cm×10.0 cm. For 2 relatively wide wounds and 2 adjacent fingers/toes wounds, the lobulated flaps centered on 2 medial sural artery perforators were designed and incised for repair. For other wounds, medial sural artery perforator flaps were designed and incised. The flap area was 5.0 cm×3.0 cm-16.0 cm×11.0 cm. The arteriovenous vessels of flap were anastomosed end-to-end with the arteriovenous vessels of the recipient area; the cutaneous nerves of 10 flaps were anastomosed with the nerves in hand wound, and the sural nerve bundle was cut to repair one digital nerve defect. The donor site wound was closed with tension-relieving sutures. Postoperative flap survival and wound healing at donor site were recorded. During follow-up, subsequent flap revision was recorded, the texture and appearance of the flap, as well as the scarring and functional recovery of the donor area of the lower leg, were observed. At the last follow-up, the recovery of hand flap sensation was observed, the satisfaction of patients with the treatment effect of each operation was investigated by using Likert scale, the hand function of the affected hand in patients with hand wounds was evaluated by using the trial standards for evaluation of partial function of upper extremity by the Hand Surgery Society of Chinese Medical Association, and the weight-bearing walking ability of the affected foot in patients with foot wounds was evaluated by Holden walking ability grading.Results:There was a slight necrosis at the distal end of one flap after surgery, which healed after dressing change. All 23 flaps survived. The sutures of the two donor areas were poorly healed due to high local tension, and the second sutures were performed after debridement and drainage, and the healing was good. The wounds of the remaining 21 donor sites healed well. Follow-up of 6-26 months after surgery showed that 3 flaps were slightly bloated, and the appearance was improved after flap reconstruction; the other flaps did not undergo subsequent revision. All flaps were soft and similar to the surrounding tissue morphology. Linear scar remained in the donor site of the lower leg, and walking function was normal. At the last follow-up, the protective sensation of the hand flap was restored; the patients were very satisfied with the results of 21 surgeries and were relatively satisfied with the results of 2 surgeries. Among the 14 patients with hand wounds, the affected hand function was rated as excellent in 10 cases, very good in 3 cases, and acceptable in one case, and the weight-bearing walking ability of the affected foot in 7 patients with foot wounds was all rated as grade Ⅴ.Conclusions:The medial sural artery perforator flap has the advantages of reliable blood supply, appropriate thickness and smoothness, and can be lobulated or cut according to the shape of the wound. The flap demonstrates superior aesthetic and functional restoration in repairing electrical burn wounds on hands and feet, achieving high patient satisfaction with the surgical treatment effect.

Objective:To evaluate the effect of transnasal humidified rapid insufflation ventilatory exchange (THRIVE) on regional cerebral oxygen saturation (rScO 2) during induction of general anesthesia in patients undergoing traumatic brain injury (TBI) emergency surgery. Methods:A prospective randomized controlled trial was conducted. The TBI emergency general anesthesia patients who underwent intracranial hematoma removal surgery at the Northern Jiangsu People's Hospital from January to July in 2023 were enrolled. The patients were divided into a conventional mask ventilation group and a THRIVE group using a random number table method. The patients in the conventional mask ventilation group were anesthetized and induced to pre oxygenate without positive pressure ventilation in the front mask for 10 minutes, with an oxygen flow rate of 8 L/min and an fraction of inspired oxygen (FiO 2) of 1.00. After anesthesia induction for about 90 s, tracheal intubation was performed after the muscle relaxant took effect (patient's jaw muscle was relaxed). The patients in the THRIVE group were pre oxygenated with THRIVE for 10 minutes, with an oxygen flow rate of 30 L/min and a FiO 2 of 1.00. During anesthesia induction, the oxygen flow rate was increased to 50 L/min, and anesthesia induction medication was used. The lower jaw of patient was supported with both hands to maintain airway patency, and the patient's mouth was kept closed throughout the process. After the muscle relaxant took effect (the patient's jaw muscle was relaxed), tracheal intubation was performed. At the time of patient entering the operating room, 10 minutes of pre oxygenation, and immediately after successful intubation, rScO 2 was measured on the surgical and non-surgical sides. At the same time, ultrasound was used to measure the cross-sectional area (CSA) of the gastric antrum and arterial blood gas analysis was performed. The partial pressure of end-tidal carbon dioxide (P ETCO 2) during the first mechanical ventilation after successful tracheal intubation, the incidence of hypoxemia [pulse oxygen saturation (SpO 2) < 0.95] during tracheal intubation, as well as prognostic indicators such as the length of intensive care unit (ICU) stay, total length of hospital stay, and Glasgow outcome scale (GOS) score at discharge were recorded. Results:During the study period, a total of 70 TBI patients underwent emergency general anesthesia surgery, of which 2 patients died postoperatively, 2 patients were unable to cooperate with closed mouth breathing, and 3 patients had poor ultrasound image acquisition in the gastric antrum, all of whom were excluded. A total of 63 patients were ultimately enrolled, including 32 in the conventional mask ventilation group and 31 in the THRIVE group. There were no statistically significant differences in gender, age, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, Glasgow coma scale (GCS) score, optic nerve sheath diameter (ONSD), baseline vital signs, fasting situation, anesthesia time, surgical time, and intraoperative blood loss between the patients in the two groups, indicating comparability. When entering the operating room, there was no statistically significant difference in rScO 2 on the surgical and non-surgical sides, and blood gas analysis indexes arterial partial pressure of oxygen (PaO 2) and arterial partial pressure of carbon dioxide (PaCO 2) between the patients in the two groups. When pre oxygenated for 10 minutes, both the surgical and non-surgical sides rScO 2 levels in the THRIVE group were significantly higher than those in the conventional mask ventilation group (surgical side: 0.709±0.036 vs. 0.636±0.028, non-surgical side: 0.791±0.016 vs. 0.712±0.027, both P < 0.01), and the PaO 2 was significantly increased [mmHg (1 mmHg≈0.133 kPa): 450.23±60.99 vs. 264.88±49.33, P < 0.01], PaCO 2 was significantly reduced (mmHg: 37.81±3.65 vs. 43.59±3.76, P < 0.01), and the advantage continues tilled immediately after successful intubation. There was no statistically significant difference in CSA at each time point of ultrasound examination between the two groups. Compared with the conventional mask ventilation group, the patients in the THRIVE group showed a significant decrease in P ETCO 2 during the first mechanical ventilation after successful tracheal intubation (mmHg: 43.10±2.66 vs. 49.22±3.31, P < 0.01), and the incidence of hypoxemia during tracheal intubation was also significantly reduced [0% (0/31) vs. 28.12% (9/32), P < 0.01]. In terms of prognostic indicators, there was no statistically significant difference in the length of ICU stay and total length of hospital stay between the patients in the conventional mask ventilation group and the THRIVE group [length of ICU stay (days): 10 (9, 10) vs. 10 (9, 11), total length of hospital stay (days): 28.00 (26.00, 28.75) vs. 28.00 (27.00, 29.00), both P > 0.05]. However, the proportion of patients in the THRIVE group with a good prognosis at discharge (GOS score > 3) was significantly higher than that in the conventional mask ventilation group [35.5% (11/31) vs. 12.5% (4/32), P < 0.05]. Conclusion:THRIVE can significantly increase rScO 2 during anesthesia induction in TBI emergency surgery patients and improve their neurological function prognosis.

Objective:To explore the mechanism of peritoneal dialysis solution (PDS)-induced peritoneal microinflammation through activation of ceramide (CER) in peritoneal dialysis model mice.Methods:Thirty 5-week-old male C57BL/6 mice weighing about 22 g were used to set up peritoneal dialysis models, and then were randomly divided into 4 groups: sham operation group (1.5 ml sterilized water, n=7), high glucose-PDS group (1.5 ml 4.25% PDS, n=8), high glucose-PDS+ acid sphingomyelinase (ASMase) inhibitor desipramine (DES) group (1.5 ml sterilized water+10 mg/kg DES, n=8), high glucose-PDS+Src kinase inhibitor PP2 group (1.5 ml sterilized water +1 mg/kg PP2, n=7), with intraperitoneal injection once a day. After 28 days, the mice were sacrificed to retain peritoneal tissues. HE staining and Masson staining were used to observe the histological changes of peritoneum. Immunohistochemistry was used to detect the Toll-like receptor 4 (TLR4) and macrophages. High performance liquid chromatography, liquid chromatography/mass spectrometry and immunofluorescence were used to detect the expression of ASMase and CER. Real-time quantitative PCR was used to detect the mRNA levels of c-Src, p-Src, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Western blotting was used to detect the protein levels of c-Src, and p-Src. Enzyme-linked immunosorbent assay was used to detect the serum C reactive protein (CRP), IL-6 and TNF-α. Results:(1) High glucose-PDS led to peritoneal hyperplasia, collagen deposition and fibrosis in the peritoneal dialysis mice, indicating successful modeling. Compared with high glucose-PDS group, peritoneal hyperplasia, collagen deposition and fibrosis of mice treated with DES and PP2 were significantly improved (all P<0.05). (2) Compared with sham operation group, ASMase activation and CER level of peritoneal tissues were significantly higher in high glucose-PDS group, and DES could significantly inhibit activated ASMase and increased CER expression caused by high glucose-PDS (both P<0.05). PP2 had no significant effect on ASMase activation and CER level (both P>0.05). (3) Compared with sham operation group, there were more TLR4 and macrophage positive staining cells in peritoneal tissues in high glucose-PDS group, and the mRNA expression levels of IL-6 and TNF-α in peritoneal tissues and serum CRP, IL-6 and TNF-α were higher (all P<0.05). DES and PP2 could significantly inhibit the increased TLR4, macrophages and related inflammatory factors induced by high glucose-PDS (all P<0.05). (4) Compared with sham operation group, c-Src and p-Src mRNA and protein expression levels of peritoneal tissues in high glucose-PDS group were significantly higher (all P<0.05). PP2 significantly inhibited the increased p-Src mRNA and protein levels caused by high glucose-PDS (both P<0.05), but had no significant effect on the mRNA and protein expression levels of c-Src (both P>0.05). DES had no significant effect on the mRNA and protein expression levels of c-Src and p-Src (all P>0.05). Conclusions:High glucose-PDS may enhance the expression of CER through stimulating the activity of ASMase, phosphorylate Src, activate TLR4 and induce inflammatory damage of peritoneum in peritoneal dialysis model mice.

Objective To explore the effect of Endoanal advancement flap(ERAF)and transanal opening of interphincteric space(TROPIS)in the treatment of complex anal fistula and their impact on anorectal pressure,so as to provide a reference for clinical selection of surgical methods.Methods Eighty-four patients with complex anal fistula admitted from October 2018 to October 2022 were divided into group E received ERAF treatment(n=48)and group T received TROPIS treatment(n=36).The clinical efficacy,operation,wound surface and anorectal pressure of the two groups were compared.Results The effective rate of treatment in Group T was 97.22％,which was higher than that in Group E(87.50％),with no statistically significant difference(P＞0.05).The surgical time[(31.53 ±7.29)minutes],intraoperative bleeding volume[(29.56±7.37)ml],and wound area[(10.03± 0.96)cm2,(8.76±0.87)cm2,(6.20±0.77)cm2]on the day of surgery,7 and 14 days after surgery in Group T were all smaller than those in Group E[(35.36±8.54)min,(36.86±8.04)ml,(12.09± 1.23)cm2,(10.52±1.09)cm2 and(7.36±0.85)cm2](P＜0.05).After surgery,the VAS score and Wexner incontinence score of Group T were(1.38±0.27)and(0.21±0.08),respectively.Group E was(1.56±0.29)and(0.33±0.09),respectively.In group T,the anorectal systolic pressure at 20 mm and 30 mm and the anorectal resting pressure at 20 mm and 30 mm were(138.18±29.58)mmHg,(136.22±35.41)mmHg,(35.47±6.58)mmHg,and(32.97±8.01)mmHg,respectively.In Group E,the data was(152.78±31.53)mmHg,(156.29±32.74)mmHg,(38.29±7.62)mmHg and(36.41±7.63)mmHg,respectively.Both groups showed a decrease in score and anorectal pressure,and group T was lower than group E(P＜0.05).The incidence of adverse reactions in Group E was 20.83％,which was higher than that in Group T(11.11％),but the difference was not statistically significant(P＞0.05).Conclusion TROPIS has a better effect in the treatment of complex anal fistula,which can shorten the operation time,reduce intraoperative bleeding,reduce postoperative pain,and protect anal function.

Objective To observe the influence of functional ankle instability(FAI)on balance and lower limb explosive power. Methods A total of 26 male FAI participants,13 bilateral(bilateral group)and 13 left(left group),who regularly en-gaged in high-intensity exercise,were recruited at Harbin Sport University in May,2024.Meanwhile,13 unin-jured male participants who engaged in high-intensity exercise were recruited as control group.They were mea-sured the moving area of the left foot,right foot and body center of gravity standing on feet with the eyes opened and closed;as well as the sway angle,confidence ellipse diameter(maximum and minimum)to circle area ratio,sway ratio and confidence ellipse standing on single foot,with Gaitview plantar pressure analysis system.They were also tested with Y-balance test(YBT),and were measured flight time and center of gravity height during jumps single leg left/right drift,stiffness and counter movement jump using Opto-jump Optical Measurement of Motor Quality. Results There were significant differences among the groups in swing angle,confidence ellipse diameter(maximum and minimum)to circle area ratio,swing ratio and confidence ellipse as left-leg stance with eyes closed(F>3.300,P<0.05),which was the least in the control group(P<0.05).Swing angle,swing ratio and confidence ellipse were also different among the groups as right-leg stance with eyes closed(F>4.404,P<0.05),and they were less in the control group than in the bilateral group(P<0.05),and less in the left group than in the bilateral group(P<0.05),except swing angle.There was a significant difference in YBT results(F>3.649,P<0.05),which was the least in the bilateral group(P<0.05).There were significant differences in the flight time and center of gravity height during counter movement jump(F>7.458,P<0.01),which was the least in the bilateral group(P<0.05). Conclusion FAI may impair the static balance as single-leg stance with eyes closed,dynamic balance and lower limb ex-plosive power.

Objective: To examine the association between serum vitamin D level and thyroid function indicators among elderly patients with type 2 diabetes mellitus (T2DM), so as to provide the evidence for the prevention and treatment of thyroid function abnormality among elderly patients with T2DM. Methods: Inpatients aged 60 years and older and admitted to the department of endocrinology of Zhejiang Hospital were selected as the study subjects. Gender, age, course of disease and other basic information were collected through questionnaire surveys. The serum 25-hydroxyvitamin D[25-(OH) D], thyroid stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), total triiodothyronine (TT3), and total thyroxine (TT4) were measured. The correlation between serum vitamin D level and thyroid function indicators in elderly patients with T2DM was evaluated by a multiple linear regression model. Results: A total of 402 elderly patients with T2DM were surveyed, including 210 males (52.24%) and 192 females (47.76%), and had a median age of 70.00 (interquartile range, 12.00) years and a median course of disease of 14.00 (interquartile range, 14.00) years. There were 162 patients with insufficiency of vitamin D (40.30%) and 182 patients with deficiency (45.27%). The levels of TSH and glycated hemoglobin in the vitamin D deficiency group were (2.34±1.66) μIU/mL and (8.83±2.14) %, respectively, which were higher than those in the normal group [(1.74±1.10) μIU/mL and (8.11±1.75) %; P<0.05]. The levels of FT3 and FT3/FT4 in the vitamin D deficiency group were (2.86±0.48) μIU/mL and 2.85±0.71, respectively, which were lower than those in the vitamin D insufficiency group [(3.09±0.47) pg/mL and 3.14±0.81, P<0.05]. Multiple linear regression analysis showed a negative correlation between 25- (OH) D and TSH (β'=-0.159, P=0.001). Conclusion The vitamin D deficiency may be associated with the increase of TSH level among the elderly patients with T2DM.

Objective:To evaluate the effect of individualized positive end-expiratory pressure (PEEP) titration based on open-lung strategy on the intraoperative thoracic fluid content (TFC) in elderly patients undergoing transurethral ultrasound-guided laser-induced prostatectomy (TULIP).Methods:Eighty-six American Society of Anesthesiologists Physical Status classification Ⅱ or Ⅲ, patients, aged 65-80 yr, with body mass index of 18-28 kg/m 2, scheduled for elective TULIP, were divided into 2 groups ( n=43 each) by the random number table method: fixed PEEP group (group C) and individualized PEEP titration group (group P). PEEP was set at 4 cmH 2O after routine mechanical ventilation in group C. Patients underwent pulmonary recruitment maneuvers combined with individualized PEEP titration during surgery in group P. TFC was measured using a non-invasive cardiac output monitor at 5 min after tracheal intubation (T 0), 30 min after PEEP titration and ventilation (T 1), 5 min before surgery (T 2), and 5 min before leaving the recovery room (T 3). Cardiac output, oxygenation index and stroke volume index were recorded from T 0-T 2, arterial blood gas analysis was simultaneously performed to record peak airway pressure and dynamic lung compliance, and oxygenation index was calculated. The duration of postanesthesia care unit stay, pulmonary complications within 7 days after surgery, and length of hospital stay were also recorded. Results:Eighty-three patients were finally included, with 42 in group C and 41 in group P. Compared with group C, TFC was significantly decreased at T 1-T 3, cardiac index, cardiac output and stroke volume index were decreased at T 1, dynamic lung compliance, PaO 2 and oxygenation index were increased at T 1 and T 2, PaCO 2 was decreased, the incidence of postoperative pulmonary complications was reduced, and the duration of postanesthesia care unit stay and postoperative length of hospital stay were shortened in group P ( P<0.05). Conclusions:Individualized PEEP titration based on open-lung strategy can effectively decrease TFC and improve intraoperative oxygenation and prognosis in elderly patients undergoing TULIP.