Perioperative Respiratory-Adverse Events Following General Anesthesia Among Pediatric Patients After COVID-19

BACKGROUND

The perianesthetic morbidity, mortality risk and anesthesia-associated risk after preoperative coronavirus disease 2019 (COVID-19) omicron variant in pediatric patients have not been fully demonstrated. We examined the association between preoperative COVID-19 omicron diagnosis and the incidence of overall perioperative adverse events in pediatric patients who received general anesthesia.

METHODS

This retrospective study included patients aged < 18 years who received general anesthesia between February 1 and June 10, 2022, in a single tertiary pediatric hospital. They were divided into two groups; patients in a COVID-19 group were matched to patients in a non-COVID-19 group during the omicron-predominant period in Korea. Data on patient characteristics, anesthesia records, post-anesthesia records, COVID-19-related history, symptoms, and mortality were collected. The primary outcomes were the overall perioperative adverse events, including perioperative respiratory adverse events (PRAEs), escalation of care, and mortality.

RESULTS

In total, 992 patients were included in the data analysis (n = 496, COVID-19; n = 496, non-COVID-19) after matching. The overall incidence of perioperative adverse events was significantly higher in the COVID-19 group than in the non-COVID-19 group (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.89-1.94). The difference was significant for PRAEs (OR, 2.00; 95% CI, 1.96-2.02) but not in escalation of care or mortality. The most pronounced difference between the two groups was observed in instances of high peak inspiratory pressure ≥ 25 cmH2O during the intraoperative period (OR, 11.0; 95% CI, 10.5-11.4). Compared with the non-COVID-19 group, the risk of overall perioperative adverse events was higher in the COVID-19 group diagnosed 0-2 weeks before anesthesia (OR, 6.5; 95% CI, 2.1-20.4) or symptomatic on the anesthesia day (OR, 6.4; 95% CI, 3.30-12.4).

CONCLUSION

Pediatric patients with the preoperative COVID-19 omicron variant had increased risk of PRAEs. Patients within 2 weeks after COVID-19 or those with symptoms had a higher risk of PRAEs.

Pulmonary artery catheter monitoring versus arterial waveform-based monitoring during liver transplantation: a retrospective cohort study

Although pulmonary artery catheter (PAC) has been used during liver transplantation surgery, the usefulness of PAC has rarely been investigated. We evaluated whether the use of PAC is associated with better clinical outcomes compared to arterial waveform-based monitoring after liver transplantation. A total of 1565 cases undergoing liver transplantation were reviewed. We determined whether patients received PAC or not and divided our cohort into the PAC with hemodynamic monitoring using PAC and the non-PAC with arterial waveform-based monitoring using FloTrac-Vigileo. Propensity score matching was performed. Acute kidney injury (AKI), early allograft dysfunction (EAD) and 1-year all-cause mortality or graft failure were compared in the matched cohorts. Logistic regression analysis was performed in the inverse probability of treatment-weighted (IPTW) cohort for postoperative EAD and AKI, respectively. Five-year overall survival was compared between the two groups. In the matched cohort, there was no significant difference in the incidence of AKI, EAD, length of hospital or ICU stay, and 1-year all-cause mortality between the groups. In the IPTW cohort, the use of PAC was not a significant predictor for AKI or EAD (AKI: odds ratio (95% confidence interval) of 1.20 (0.47-1.56), p = 0.229; EAD: 0.99 (0.38-1.14), p = 0.323). There was no significant difference in the survival between groups after propensity score matching (Log-rank test p = 0.578). In conclusion, posttransplant clinical outcomes were not significantly different between the groups with and without PAC. Anesthetic management without the use of PAC may be possible in low-risk patients during liver transplantation. The risk should be carefully assessed by considering MELD scores, ischemic time, surgical history, previous treatment of underlying liver disease, and degree of portal and pulmonary hypertension.Registration: https://clinicaltrials.gov/ct2/show/NCT05457114 (registration date: July 15, 2022).

High peak inspiratory pressure may be associated with intraoperative coughing during neurosurgery under general anesthesia without neuromuscular blockade: a retrospective study

BACKGROUND

The endotracheal cuff pressure depends on the airway pressure during positive-pressure ventilation. A high endotracheal cuff pressure may be related to intraoperative coughing, which can be detrimental during neurosurgery. We investigated the incidence of intraoperative coughing and its association with peak inspiratory pressure (PIP) during neurosurgery under general anesthesia without neuromuscular blockade.

METHODS

This retrospective study divided 1656 neurosurgical patients who underwent total intravenous anesthesia without additional neuromuscular blockade after tracheal intubation into high (PIP > 21.6 cmH₂O, n = 318) and low (PIP ≤ 21.6 cmH₂O, n = 1338) PIP groups. After propensity score matching, 206 patients were selected in each group. Demographic, preoperative, surgical, and anesthetic data were collected retrospectively from electronic medical records and continuous ventilator, infusion pump, and bispectral index data from a data registry.

RESULTS

Intraoperative coughing occurred in 30 (1.8%) patients, including 9 (0.5%) during the main surgical procedure. Intraoperative coughing was more frequent in the high PIP group than in the low PIP group before (14/318 [4.4%] vs. 16/1338 [1.2%], P < 0.001) and after (13/206 [6.3%] vs. 1/206 [0.5%], P = 0.003) propensity score matching. In multivariable logistic regression analysis after propensity score matching, a high PIP (odds ratio [95% confidence interval] 14.22 [1.81-111.73], P = 0.012), tidal volume divided by predicted body weight (mL/kg, 1.36 [1.09-1.69], P = 0.006), and surgical duration (min, 1.01 [1.00-1.01], P = 0.025) predicted intraoperative coughing.

CONCLUSION

The incidence of intraoperative coughing was 1.8% in neurosurgical patients undergoing general anesthesia without neuromuscular blockade and might be associated with a high PIP.

Continuous versus Intermittent Infusion of Human Antithrombin III Concentrate in the Immediate Postoperative Period after Liver Transplantation

Antithrombin-III (AT-III) concentrates have been used in the immediate postoperative period after liver transplantation to prevent critical thrombosis. We aimed to investigate more appropriate method for AT-III concentrate administration to maintain plasma AT-III activity level within targeted range. In this randomized controlled trial, 130 adult patients undergoing living-donor liver transplantation were randomized to either intermittent group or continuous group. In intermittent group, 500 international units (IU) of AT-III concentrate were administered after liver transplantation and repeated every 6 hours for 72 hours. In continuous group, 3000 IU of AT-III was continuously infused for 71 hours after a loading dose of 2000 IU over 1 hour. Plasma AT-III activity level was measured at 12, 24, 48, 72, and 84 hours from the first AT-III administration. The primary outcome was the target (80-120%) attainment rate at 72 hours. Target attainment rates at other time points and associated complications were collected as secondary outcomes. A total of 107 patients were included in the analysis. The target attainment rates at 72 hours post-dose were 30% and 62% in intermittent group and continuous group, respectively. (p=0.003) Compared to intermittent group, patients in continuous group reached the target level more rapidly (12 vs. 24 hours, median time, p<0.001) and was more likely to remain in the target range until 84 hours. For maintaining the target plasma AT-III activity level after living-donor liver transplantation, continuous infusion of AT-III seemed to be more appropriate compared to the conventional intermittent infusion regimen.

Effect of a repeated verbal reminder of orientation on emergence agitation after general anaesthesia for minimally invasive abdominal surgery: a randomised controlled trial

BACKGROUND

An orientation strategy providing repeated verbal reminders of time, place, and person has been widely used for the non-pharmacological management of delirium. We hypothesised that using this strategy could reduce emergence agitation and improve recovery profiles.

METHODS

This prospective observer-blinded RCT included male and female patients aged 18-70 yr undergoing minimally invasive abdominal surgery. During emergence from general anaesthesia, subjects in the orientation group (n=57) were provided a repeated reminder, including orientation: '(Patient's name), you are now recovering from general anaesthesia after surgery at Seoul National University Hospital, open your eyes!' via noise-cancelling headphones, whereas those in the control group (n=57) only heard their name: '(Patient's name), open your eyes!'. The primary outcome was the incidence of emergence agitation (Riker sedation agitation scale [SAS] ≥5). The incidence of dangerous agitation (SAS=7), maximal SAS score in the operating room, and recovery profile until 24 h postoperatively were evaluated as secondary outcomes.

RESULTS

The incidence of emergence agitation in the operating room was significantly lower in the orientation group than in the control group (16/57 [28.1%] vs 38/57 [66.7%]; relative risk [95% confidence interval], 0.5 [0.3-0.7]; P<0.001). The incidence of dangerous agitation (0 [0.0%] vs 10 [17.5%], P=0.001) and the median maximal SAS score (4 [4-5] vs 5 [4-6], P<0.001) were also lower in the orientation group. Secondary outcomes, other than agitation-related variables, were comparable between the two groups.

CONCLUSIONS

Repeated verbal stimulation of orientation may serve as a simple and easily applicable strategy to reduce emergence agitation after general anaesthesia.

CLINICAL TRIAL REGISTRATION

NCT05105178.

Association between intraoperative body temperature and postoperative delirium: A retrospective observational study

STUDY OBJECTIVE

The effect of perioperative body temperature derangement on postoperative delirium remains unclear. This study aimed to evaluate the association between intraoperative body temperature and postoperative delirium in patients having noncardiac surgery.

DESIGN

Single-center retrospective observational study.

SETTING

Tertiary university hospital.

PATIENT

Adult patients who had major noncardiac surgery under general anesthesia for at least two hours between 2019 and 2021.

INTERVENTIONS

Patients were classified into three groups according to their intraoperative time-weighted average body temperature: severe hypothermia (<35.0 °C), mild hypothermia (35.0 °C-36.0 °C), and normothermia (≥36.0 °C) groups.

MEASUREMENTS

The primary outcome was the risk of delirium occurring within seven days after surgery, which was compared using logistic regression analysis. A multivariable procedure was performed adjusting for potential confounders including demographics, history of hypertension, diabetes, atrial fibrillation or flutter, myocardial infarction, congestive heart failure, and stroke or transient ischemic attack, preoperative use of antidepressants and statins, preoperative sodium imbalance, high-risk surgery, emergency surgery, duration of surgery, and red blood cell transfusion. Cox regression analysis was also performed using the same covariates.

MAIN RESULTS

Among 27,674 patients analyzed, 5.5% experienced postoperative delirium. The incidence rates of delirium were 6.2% (63/388) in the severe hypothermia group, 6.4% (756/11779) in the mild hypothermia group, and 4.6% (712/15507) in the normothermia group. Compared with the normothermia group, the risk of delirium was significantly higher in the severe hypothermia (adjusted odds ratio, 1.43; 95% confidence interval, 1.04-1.97) and mild hypothermia (1.15; 1.02-1.28) groups. The mild hypothermia group also had a significantly increased risk of cumulative development of delirium than the normothermia group (adjusted hazard ratio 1.14; 95% confidence interval, 1.03-1.26).

CONCLUSIONS

Intraoperative hypothermia (even mild hypothermia) was significantly associated with an increased risk of postoperative delirium.

Effect of pre-operative carbohydrate loading on aspiration risk evaluated with ultrasonography in type 2 diabetes patients: a prospective observational pilot study

Owing to concerns about delayed gastric emptying or hyperglycemia, evidence is lacking regarding whether pre-operative carbohydrate loading can be routinely administered to patients with type 2 diabetes. The objective of this study was to determine the aspiration risk and gastric volume after pre-operative carbohydrate loading in patients with type 2 diabetes. A prospective, single-center, observational cohort study. The study was conducted at a tertiary teaching hospital in Seoul, Korea, from May 2020 to May 2021. Patients (n = 49) with type 2 diabetes underwent elective noncardiac surgery. All patients were administered carbohydrate loading two hours before surgery. Once in the operating room, they underwent gastric ultrasonography to determine gastric volume. The anesthesiologists monitored the patients' glucose concentrations during and after surgery. The primary outcome was the predicted risk of aspiration. The secondary outcomes were gastric volume, antral grade, satisfaction score, and perioperative glucose profile. Forty-nine patients were analyzed. All patients had a low risk of aspiration after carbohydrate loading, as follows: 33 (67.3%) patients classified as antral grade 0 and 16 (32.7%) patients classified as antral grade 1. The median time from carbohydrate drink ingestion to ultrasound examination was 120 min (IQR 115-139). After carbohydrate loading, the median gastric volume in the right-lateral position after carbohydrate loading was 2.64 ml (IQR 0.00-32.05). The mean glucose concentrations (SD) were 134 (24) mg/dl, 159 (37) mg/dl, 150 (32) mg/dl, and 165 (36) mg/dl at baseline, after induction, 30 min after surgery, and in the post anesthesia care unit, respectively. The median satisfaction score of the patients was 5 (IQR 4-5). Pre-operative carbohydrate loading may be feasible for patients with type 2 diabetes and without complications.Trial registration: ClinicalTrials.gov (NCT04456166). Registered on 2 July 2020.

Observation of Coulomb-Assisted Nuclear Bound State of Ξ^{-}-^{14}N System

In an emulsion-counter hybrid experiment performed at J-PARC, a Ξ^{-} absorption event was observed which decayed into twin single-Λ hypernuclei. Kinematic calculations enabled a unique identification of the reaction process as Ξ^{-}+^{14}N→_{Λ}^{10}Be+_{Λ}^{5}He. For the binding energy of the Ξ^{-} hyperon in the Ξ^{-}-^{14}N system a value of 1.27±0.21  MeV was deduced. The energy level of Ξ^{-} is likely a nuclear 1p state which indicates a weak ΞN-ΛΛ coupling.

Morphological Study of Poly(vinylbenzyl chloride)-Grafted Poly(ethylene-co-tetrafluoroethylene) [ETFE-g-PVBC] Films Using Small-Angle Neutron Scattering Analysis

In this study, the effect of degree of the grafting and crosslinking on the morphology of the crystalline domain in poly(vinylbenzyl chloride)-grafted poly(ethylene-co-tetrafluoroethylene) [ETFE-g-PVBC] films was investigated using a SANS (small-angle neutron scattering) analysis. The grafted films can be used as a precursor for ion-exchange membrane. ETFE-g-PVBC films with various degrees of cross-linking were prepared by a simultaneous irradiation grafting of vinylbenzyl chloride (VBC) and divinylbenzene (DVB) onto an ETFE film. The SEM-EDX (scanning electron microscopy-energy dispersive X-ray spectroscopy) results of a cross-sectional distribution of ETFE-g-PVBC films showed that the chlorine atoms were well-distributed throughout the films. SANS profiles of the PVBC-grafted films in the absence of a DVB crosslinker showed that the crystalline domain peaks were observed and the peak maximum position shifted significantly from 0.032 Å-(-1) to 0.02 Å(-1) with an increase in the degree of grafting. However, peak maximum positions of the PVBC-grafted films in the presence of a DVB crosslinker shifted slightly from 0.02 Å(-1) to 0.024 Å(-1) with an increase in the amount of DVB monomer at same degree of grafting. These results indicate that the degree of grafting and crosslinking affect the morphology of the crystalline domain in the ETFE-g-PVBC films.

Allogeneic renal graft rejection in a rat model: in vivo MR imaging of the homing trait of macrophages

PURPOSE

To evaluate the feasibility of MR imaging to depict the in vivo recruitment of superparamagnetic iron oxide (SPIO)-labeled macrophages and to aid diagnosis of graft rejection in kidney transplantation.

MATERIALS AND METHODS

This study was approved by the institution's committee on animal research. Eighteen male Lewis rats received a kidney transplant; 12 had an F344 rat donor and six had a Lewis rat donor. Peritoneal macrophages were harvested from thioglycollate-treated Lewis rats, cultured, and labeled with SPIO. After resuspension of macrophages in a concentration of 1 x 10(7) cells per milliliter of Hanks balanced salt solution, 5 x 10(6) of SPIO-labeled macrophages was administered through the tail vein 2 or 5 days after transplantation in each group. The transplanted kidneys were imaged on a 4.7-T MR imager 24 hours after macrophage administration. The Wilcoxon signed rank test was performed for evaluating the differences between the relative signal intensity (SI) before and after SPIO-labeled macrophage administration.

RESULTS

A low-SI zone was predominantly noted in the medulla of the transplanted kidneys, and the relative SI decreased significantly from 1.40 to 0.53 (P < .001) in the allogeneic transplants following SPIO-labeled macrophage administration 5 days after the allogeneic transplantation. In the syngeneic group, the lower-SI zone was not noted in the grafts. At histopathologic examination, the lower-SI zone corresponded to the distribution of the SPIO-labeled macrophages.

CONCLUSION

This study demonstrates that the homing of intravenously administered SPIO-labeled macrophages can be monitored in the allograft rejection model on in vivo MR images.

Invisible plasmonic meta-materials through impedance matching to vacuum

We report on perfect transmission in two-dimensional plasmonic matamaterials in the terahertz frequency range, in which zeroth order transmittance becomes essentially unity near specific resonance frequencies. Perfect transmission may occur when the plasmonic metamaterials are perfectly impedance matched to vacuum, which is equivalent to designing an effective dielectric constant around epsilonr = -2. When the effective dielectric constant of the metamaterial is tuned towards epsilonr and the hole coverage is larger than 0.2, strong evanescent field builds up in the near field, making perfect transmission possible.

Molecular lens of the nonresonant dipole force

A cylindrical molecular lens is formed by focusing a nanosecond IR laser pulse. Trajectories of a CS2 molecular beam deflected by the lens are traced using the velocity map imaging technique. The characteristic lens parameters including the focal length, minimum beam width, and distance to the minimum-width position are determined. The laser intensity dependence of the parameters is in good agreement with theoretical predictions. Exciting possibilities for molecular optics and a new type of optical chromatography are opened up.

Two-color femtosecond experiments by use of two independently tunable Ti:sapphire lasers with a sample-and-hold switch

We performed femtosecond two-color experiments (four-wave mixing and pump probe) using two independently tunable, partially synchronized femtosecond lasers. Despite the fact that the jitter is of the order of 5-10 ps, the time resolution is limited only by the pulse width when a homemade sample-and-hold switch is used.

Transient temperature responses of hydronic radiant floor heating system by different pipe embedding depth and water supply condition

"Ondol" is a Korean unique heating system. It is a specific radiant floor heating system using combustion heat of briquette or timber in Korea. Such traditional "Ondol" is changed to radiant heating system with pipe-coil embedded in the floor or slab. This study has contributed to the understandings of the transient behaviours of Ondol-heated floor panels and enclosure exposed to this type of heating system. The result is that the water supply temperature had a large effect on the rate of increase in floor surface and room air temperature. But, in spite of a higher water supply temperature, the heat flow rate was not increased considerably. The shallow pipe embedding depths, of course, result in a low heat flow rate.

Optimum comfort limits determination through the characteristics of asymmetric thermal radiation in a heated floor space, "ondol"

This study was undertaken to evaluate the effects of the asymmetric radiation on thermal comfort, and to suggest the optimum comfort limits in a radiant heating space. The index of V.R.T. (Vector Radiant Temperature) was used to describe the environmental quality of the heated floor space. Optimum comfort limits of this space were suggested through both theoretical and empirical studies. It is recommended to use not only man's sensation of the ambient air but also that of the floor surface for the determination of the optimum comfort limits on the heated floor space such as an "Ondol" in Korea. In the present study the optimum comfort limits were suggested in terms of the V.R.T. The optimum limits obtained were as follows: the vector radiant temperature 11.0 approximately 15.0 K.