Over 3.8 W, 3.4†µm picosecond mid-infrared parametric conversion based on a simplified one-to-many scheme.

In this paper, we demonstrate a simplified one-to-many scheme for efficient mid-infrared (MIR) parametric conversion. Such a scheme is based on a continuous wave (CW) single longitudinal mode master oscillator power-amplifier (MOPA) fiber system as the signal source and a picosecond pulsed MOPA fiber system, exhibiting multiple longitudinal modes, as the pump source. The signal and pump beams are combined and co-coupled into a piece of 50-mm long 5% MgO-doped PPLN crystal for the parametric conversion. As high as ∼3.82 W average power at a central idler wavelength of ∼3.4 µm is achieved when the launched pump and signal powers are ∼41.73 and ∼11.45 W, respectively. Above some threshold value, the delivered idler power shows a roll-over effect against the signal power and saturation-like effect against the pump power. Consequently, the highest conversion efficiency is observed at such a threshold pump power. To the best of our knowledge, our result represents the highest average power produced from any single-pass parametric conversion source with >3 µm idler wavelength feeding with a CW signal. Moreover, our proposed scheme can simplify the design of parametric conversion system significantly and meanwhile make the system more robust in applications. This is attributed to two main aspects. Firstly, the scheme's one-to-many feature can reduce wavelength sensitivity remarkably in the realization of quasi-phase-matching. Secondly, for moderate power requirement it does not always require a high peak power synchronized pulsed signal source; a CW one can be an alternative, thereby making the system free from complex time synchronization and the related time jitter.

Comparison of three frailty scales for prediction of prolonged postoperative ileus following major abdominal surgery in elderly patients: a prospective cohort study.

BACKGROUND: To determine whether frailty can predict prolonged postoperative ileus (PPOI) in older abdominal surgical patients; and to compare predictive ability of the FRAIL scale, the five-point modified frailty index (mFI-5) and Groningen Frailty Indicator (GFI) for PPOI. METHODS: Patients (aged ≥ 65 years) undergoing major abdominal surgery at our institution between April 2022 to January 2023 were prospectively enrolled. Frailty was evaluated with FRAIL, mFI-5 and GFI before operation. Data on demographics, comorbidities, perioperative management, postoperative recovery of bowel function and PPOI occurrence were collected. RESULTS: The incidence of frailty assessed with FRAIL, mFI-5 and GFI was 18.2%, 38.4% and 32.5% in a total of 203 patients, respectively. Ninety-five (46.8%) patients experienced PPOI. Time to first soft diet intake was longer in patients with frailty assessed by the three scales than that in patients without frailty. Frailty diagnosed by mFI-5 [Odds ratio (OR) 3.230, 95% confidence interval (CI) 1.572-6.638, P = 0.001] or GFI (OR 2.627, 95% CI 1.307-5.281, P = 0.007) was related to a higher risk of PPOI. Both mFI-5 [Area under curve (AUC) 0.653, 95% CI 0.577-0.730] and GFI (OR 2.627, 95% CI 1.307-5.281, P = 0.007) had insufficient accuracy for the prediction of PPOI in patients undergoing major abdominal surgery. CONCLUSIONS: Elderly patients diagnosed as frail on the mFI-5 or GFI are at an increased risk of PPOI after major abdominal surgery. However, neither mFI-5 nor GFI can accurately identify individuals who will develop PPOI. TRIAL REGISTRATION: This study was registered in Chinese Clinical Trial Registry (No. ChiCTR2200058178). The date of first registration, 31/03/2022, https://www.chictr.org.cn/ .

A prospective study of chronic postsurgical pain in elderly patients: incidence, characteristics and risk factors.

BACKGROUND: Due to the continued growth of surgical procedures in older adults and the significant impact of chronic postsurgical pain (CPSP), it is crucial to improve our understanding of the occurrence of CPSP as well as the appropriate prevention and treatment. We therefore conducted this study to determine the incidence, characteristics and risk factors of CPSP in elderly patients at both 3 and 6 months after surgery. METHODS: Elderly patients (aged ≥ 60 years) undergoing elective surgery in our institution between April 2018 and March 2020 were prospectively enrolled in this study. Data on demographics, preoperative psychological well-being, intraoperative surgical and anesthesia management, and acute postoperative pain intensity were collected. At 3 and 6 months after surgery, patients received telephone interview and completed the questionnaires regarding chronic pain characteristics, analgesic consumption, and interference of the pain with activities of daily living (ADL). RESULTS: A total of 1065 elderly patients were followed up for 6 postoperative months and included in final analysis. At 3 and 6 months after operation, the incidence of CPSP was 35.6% [95% confidence interval (95% CI) 32.7 - 38.8%] and 21.5% (95% CI 19.0% - 23.9%), respectively. CPSP cause negative impacts on patient's ADL and most particularly on mood. Neuropathic features were found in 45.1% of the patients with CPSP at 3 months. At 6 months, 31.0% of those with CPSP reported that the pain had neuropathic features. Preoperative anxiety [3 months: Odds ratio (OR) 2.244, 95% CI 1.693 to 2.973; 6 months: OR 2.397, 95% CI 1.745 to 3.294], preoperative depression (3 months: OR 1.709, 95% CI 1.292 to 2.261; 6 months: OR 1.565, 95% CI 1.136-2.156), orthopedic surgery (3 months: OR 1.927, 95% CI 1.112 to 3.341; 6 months: OR 2.484, 95% CI 1.220 to 5.061), higher pain severity on movement within postoperative 24 h (3 months: OR 1.317, 95% CI 1.191 to 1.457; 6 months: OR 1.317, 95% CI 1.177 to 1.475) were associated with a higher risk for CPSP independently at both 3 and 6 months after surgery. CONCLUSIONS: CPSP is a common postoperative complication in elderly surgical patients. Preoperative anxiety and depression, orthopedic surgery, and greater intensity of acute postoperative pain on movement are associated with an increased risk for CPSP. It should be kept in mind that developing psychological interventions to reduce anxiety and depression and optimizing the management of acute postoperative pain will be effective in reducing the development of CPSP in this population.

The Effect of Preoperative Oral Carbohydrate on the Incidence of Complications in PACU After General Anesthesia: A Prospective Cohort Study.

PURPOSE: This study aimed to investigate the effect of preoperative oral carbohydrate (POC) loading on the occurrence of complications in the postanesthesia care unit (PACU) after general anesthesia. DESIGN: Prospective observational cohort study METHODS: Patients who were scheduled for abdominal surgery under general anesthesia at our institution were divided into the POC group and control group based on whether they drank carbohydrate solution 2 hours before surgery. POC loading of the patients was decided by the responsible surgeon. In PACU, the occurrence of postoperative complications including delayed emergence, emergence agitation, hypoxemia, hypertension, hypotension, moderate to severe postoperative pain, nausea and vomiting, hypothermia, shivering, and time to awakening, time to extubation, length of PACU stay were recorded. FINDINGS: Data from 307 patients (n = 154 in POC group and n = 153 in control group) were included in the final analysis. Compared to the control group, POC led to a near-significant reduction in the overall incidence of complications in PACU after surgery (37.0% vs 47.7%, P = .058). The POC group had a lower incidence of hypothermia and shorter mean time to awakening when compared to control group (6.5% vs 16.3%, P = .007 and 19 min vs 21 min, P = .007, respectively). No statistical differences were detected in other outcome measurements between the POC group and the control group. CONCLUSIONS: POC is associated with a trend to decrease the overall incidence of complications during recovery period after general anesthesia in patients who underwent abdominal surgery. Moreover, POC could reduce the risk of hypothermia in PACU and shorten the time to awakening.

Case Report: Anesthesia for Cesarean Section in Parturients With Chronic Renal Failure Requiring Hemodialysis: Case Reports and Literature Review.

Pregnancies are rare in women with chronic renal failure requiring hemodialysis. Although a chance of successful pregnancy and delivery in hemodialysis women has increased over the years, it is still very low, and with high maternal and fetal mortality and morbidity rate compared to normal population. And cesarean section is usually used for delivery. The first case was a 32-year-old Chinese woman with chronic kidney disease stage V undergoing maintenance hemodialysis for six years. The second case was also a 32-year-old patient with a 6-year history of hemodialysis for chronic glomerulonephritis. And due to a history of atrial septal defect and hypertension she received intensive hemodialysis during pregnancy. Both cases were scheduled for cesarean delivery under epidural anesthesia. To help develop reasonable anesthetic methods and management objectives for such patients, we described our anesthetic management and performed a literature search on published cases of cesarean section with chronic renal failure undergoing hemodialysis.

[Retrospective study on forty cases of medical legal dispute].

OBJECTIVE: To analyze the main causes of medical dispute and the main types of medical malpractice. The related problems were discussed in forensic expertise. METHODS: Forty cases of medical dispute from 2006 to 2008 in our institute were analyzed retrospectively. RESULTS: In 40 cases of medical dispute, city-level hospitals, county-level hospitals, town-level hospitals and private clinics were 11 (27.5%), 24 (60.0%), 2 (5.0%) and 3 (7.5%) cases respectively. The internal medicine departments, surgical departments, gynaecological and obstetric departments, pediatric departments and outpatient center were 16 (40.0%),10 (25.0%), 9 (22.5%), 2 (5.0%) and 3 (7.5%) cases, respectively. The amount of cases from city-level hospitals, county-level hospitals diagnosed by the medical experts as the medical malpractice showed less than that from town-level hospitals and private clinics. CONCLUSION: The amount of cases of medical dispute from city-level and county-level hospitals were more than that of town-level hospitals. But the amount of cases diagnosed by the medical experts as medical malpractice from city-level and county-level hospitals were less than that of town-level hospital and private clinics.