The Effect of Postoperative Single-Injection Adductor Canal Block in Total Knee Arthroplasty Under Spinal Anesthesia With Intraoperative Dexmedetomidine Infusion

Background

Single-injection adductor canal block (SACB) is one of the multimodal pain managements in total knee arthroplasty. The effect of an intrathecal local anesthetic is prolonged with an intraoperative dexmedetomidine infusion. Currently, SACB's effect along with the prolonged spinal anesthesia effect by dexmedetomidine has not been studied elsewhere.

Methods

Seventy-eight patients were randomized to either the SACB group (n = 39) or the control group (n = 39). Spinal anesthesia and continuous infusion of dexmedetomidine were performed intraoperatively. The SACB was performed using 15 mL of either 0.5% ropivacaine or normal saline in postanesthesia care unit postoperatively. Primary endpoint examined the average numerical rating scale (NRS) pain scores at 2, 6, 12, and 24 hours after SACB while resting or moving. The secondary outcomes were the morphine equivalent, postoperative nausea and vomiting score, quadriceps strength, and overall satisfaction score.

Results

The SACB group showed a lower average NRS pain score until 24 hours than the control group (2.4 vs 3.3 resting, 3.4 vs 4.1 moving). Resting and moving NRS scores at 6 and 12 hours were significantly lower in the SACB group, whereas no difference was found at 2, 24, and 48 hours, regardless of movement. The satisfaction score was higher in the SACB group than in the control group (9 [7.3-10.0] vs 7 [5.3-8.8]), and morphine equivalent at 2 hours was lower in the SACB group (2 [1-3]) than in the control group (2.9 [1.6-4]).

Conclusions

SACB provided an additional analgesic effect in patients undergoing total knee arthroplasty under spinal anesthesia with continuous dexmedetomidine intravenous infusion.

Determination of optimal positive end-expiratory pressure using electrical impedance tomography in infants under general anesthesia: Comparison between supine and prone positions

AIMS

This study determined the optimal positive end-expiratory pressure levels in infants in supine and prone positions under general anesthesia using electrical impedance tomography (EIT).

METHODS

This prospective observational single-centre study included infants scheduled for surgery in the prone position. An electrical impedance tomography sensor was applied after inducing general anesthesia. The optimal positive end-expiratory pressure in the supine position was determined in a decremental trial based on EIT and compliance. Subsequently, the patient's position was changed to prone. Electrical impedance tomography parameters, including global inhomogeneity index, regional ventilation delay, opening pressure, the centre of ventilation, and pendelluft volume, were continuously obtained up to 1 h after prone positioning. The optimal positive end-expiratory pressure in the prone position was similarly determined.

RESULTS

Data from 30 infants were analyzed. The mean value of electrical impedance tomography-based optimal positive end-expiratory pressure in the prone position was significantly higher than that in the supine position [10.9 (1.6) cmH2O and 6.1 (0.9) cmH2O, respectively (p < .001)]. Significant differences were observed between electrical impedance tomography- and compliance-based optimal positive end-expiratory pressure. Peak and mean airway, plateau, and driving pressures increased 1 h after prone positioning compared with those in the supine position. In addition, the centre of ventilation for balance in ventilation between the ventral and dorsal regions improved.

CONCLUSION

The prone position required higher positive end-expiratory pressure than the supine position in mechanically ventilated infants under general anesthesia. EIT is a promising tool to find the optimal positive end-expiratory pressure, which needs to be individualized.

Noninvasive hemoglobin monitoring for maintaining hemoglobin concentration within the target range during major noncardiac surgery: A randomized controlled trial

STUDY OBJECTIVE

The effect of noninvasive CO-oximetry hemoglobin (SpHb) monitoring on the clinical outcomes of patients undergoing surgery remains unclear. This trial aimed to evaluate whether SpHb monitoring helps maintain hemoglobin levels within a predefined target range during major noncardiac surgeries with a potential risk of intraoperative hemorrhage.

DESIGN

A single-center, prospective, randomized controlled trial.

SETTING

University hospital.

PATIENTS

One hundred and thirty patients undergoing elective noncardiac surgery with a potential risk of hemorrhage.

INTERVENTIONS

Patients were randomly allocated to undergo either SpHb-guided management (SpHb group) or usual care (control group).

MEASUREMENTS

The primary outcome was the rate of deviation of the total hemoglobin concentration (determined from laboratory testing) from a pre-specified target range (8-14 g/dL). This was defined as the number of laboratory tests revealing such deviations divided by the total number of laboratory tests performed during the surgery.

MAIN RESULTS

The primary outcome occurred significantly less frequently in the SpHb group as compared to that in the control group (15/555 [2.7%]) vs. 68/598 [11.4%]; relative risk, 0.24; 95% confidence interval, 0.13-0.41; P < 0.001). Fewer point-of-care blood tests were performed in the SpHb group than in the control group (median [interquartile range], 2 [1-4] vs. 4 [2-5]; P < 0.001). There were no significant intergroup differences in the number of patients who received red blood cell transfusions during surgery (SpHb vs. control, 33.8% vs. 46.2%; P = 0.201). The incidence of unnecessary red blood cell preparation (>2 units) was lower in the SpHb group than in the control group (3.1% vs. 16.9%; P = 0.024).

CONCLUSIONS

Compared with routine care, SpHb-guided management resulted in significantly lower rates of hemoglobin deviation outside the target range intraoperatively in patients undergoing major noncardiac surgeries with a potential risk of hemorrhage.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov (identifier: NCT03816514).

Effect of converting from propofol to remimazolam with flumazenil reversal on recovery from anesthesia in outpatients with mental disabilities: a randomized controlled trial

BACKGROUND

General anesthesia is often necessary for dental treatment of outpatients with mental disabilities. Rapid recovery and effective management of postoperative nausea and vomiting (PONV) are critical for outpatients. This study aimed to investigate the effect of transitioning from propofol to remimazolam with flumazenil reversal administered toward the end of surgery during propofol-based total intravenous anesthesia (TIVA) on recovery.

METHODS

Adults with mental disabilities scheduled to undergo dental treatment were randomly assigned to receive either propofol-based TIVA (Group P) or propofol-remimazolam-based TIVA with flumazenil reversal (Group PR). Propofol was replaced with remimazolam 1 h before the end of surgery in Group PR; moreover, 0.5 mg of flumazenil was administered after the neuromuscular blockade reversal agent. The primary outcome was the duration of stay in the post-anesthesia care unit (PACU). The secondary outcomes included time to eye-opening, time to extubation, occurrence of PONV, and quality of recovery.

RESULTS

Fifty-four patients were included in this study. The duration of stay in the PACU in Group PR was significantly shorter than that in Group P (mean difference, 8.7 min; confidence interval [95% CI], 3.3-14.2; P = 0.002). Group PR exhibited a shorter time to eye opening (mean difference, 5.4 min; 95% CI, 3.3-8.1; P < 0.001) and time to extubation (mean difference, 5.5 min; 95% CI, 3.6-7.9; P < 0.001) than Group P. Neither group required the administration of rescue analgesics, and the incidence of PONV was not reported.

CONCLUSIONS

Transitioning from propofol to remimazolam 1 h before the end of surgery followed by flumazenil reversal reduced the duration of stay in the PACU and the time to eye opening and extubation without affecting the incidence of PONV and quality of recovery.

TRIAL REGISTRATION NUMBER

Clinical Research Information Service (KCT0007794), Clinical trial first registration date: 12/10/2022.

Relationship between preinduction electroencephalogram patterns and propofol sensitivity in adult patients

PURPOSE

To determine the precise induction dose, an objective assessment of individual propofol sensitivity is necessary. This study aimed to investigate whether preinduction electroencephalogram (EEG) data are useful in determining the optimal propofol dose for the induction of general anesthesia in healthy adult patients.

METHODS

Seventy healthy adult patients underwent total intravenous anesthesia (TIVA), and the effect-site target concentration of propofol was observed to measure each individual's propofol requirements for loss of responsiveness. We analyzed preinduction EEG data to assess its relationship with propofol requirements and conducted multiple regression analyses considering various patient-related factors.

RESULTS

Patients with higher relative delta power (ρ = 0.47, p < 0.01) and higher absolute delta power (ρ = 0.34, p = 0.01) required a greater amount of propofol for anesthesia induction. In contrast, patients with higher relative beta power (ρ = -0.33, p < 0.01) required less propofol to achieve unresponsiveness. Multiple regression analysis revealed an independent association between relative delta power and propofol requirements.

CONCLUSION

Preinduction EEG, particularly relative delta power, is associated with propofol requirements during the induction of general anesthesia. The utilization of preinduction EEG data may improve the precision of induction dose selection for individuals.

Extubation in operating room versus early extubation in ICU after open-heart surgery in patients with CHDs

BACKGROUNDS AND OBJECTIVES

The "Fast track" protocol is an early extubation strategy to reduce ventilator-associated complications and induce early recovery after open-heart surgery. This study compared clinical outcomes between operating room extubation and ICU extubation after open-heart surgery in patients with CHD.

METHODS

We retrospectively reviewed 215 patients who underwent open-heart surgery for CHDs under the scheduled "Fast track" protocol between September 2016 and April 2022. The clinical endpoints were post-operative complications, including bleeding, respiratory and neurological complications, and hospital/ICU stays.

RESULTS

The patients were divided into operating room extubation (group O, n = 124) and ICU extubation (group I, n=91) groups. The most frequently performed procedures were patch closures of the atrial septal (107/215, 49.8%) and ventricular septal (89/215, 41.4%) defects. There were no significant differences in major post-operative complications or ICU and hospital stay duration between the two groups; however, patients in group I showed longer mechanical ventilatory support (0.0 min vs. 59.0 min (interquartile range: 17.0-169.0), p < 0.001). Patients in Group O showed higher initial lactate levels (3.2 ± 1.7 mg/dL versus 2.5 ± 2.0 mg/dL, p = 0.007) and more frequently used additional sedatives and opioid analgesics (33.1% versus 19.8%, p = 0.031).

CONCLUSIONS

Extubation in the operating room was not beneficial for patients during post-operative ICU or hospital stay. Early extubation in the ICU resulted in more stable hemodynamics in the immediate post-operative period and required less use of sedatives and analgesics.

Effectiveness of head-mounted ultrasound display for radial arterial catheterisation in paediatric patients by anaesthesiology trainees: A randomised clinical trial

BACKGROUND

The effectiveness of head mounted real-time ultrasound displays (hereafter referred to as 'smart glasses') in improving hand-eye coordination in less experienced individuals, such as trainees in anaesthesia, is unclear.

OBJECTIVES

To compare the first-attempt success rate of smart glasses-assisted ultrasound-guided paediatric radial artery catheterisation with conventional ultrasound guided catheterisation performed by anaesthesiology trainees.

DESIGN

Prospective randomised controlled trial.

SETTINGS

Tertiary university hospital from September 2021 to February 2023.

PATIENTS

One hundred and twenty-two paediatric patients (age <7 years, weight ≥3 kg) who required radial artery cannulation during general anaesthesia.

INTERVENTIONS

The participants were randomly assigned to either the ultrasound screen group (control) or the smart glasses group prior to radial artery catheterisation.

MAIN OUTCOME MEASURES

The primary outcome was the first attempt success rate. Secondary outcomes included the number of attempts, use of transfixion technique, overall complication rate, and clinical anaesthesiology (CA) year of the operators.

RESULTS

A total of 119 paediatric patients were included in the analysis. The smart glasses group exhibited higher first-attempt success rate than did the control group (89.8% [53/59] vs. 71.7% [43/60]; P = 0.023; odds ratio (OR) 3.49; (95% confidence interval (CI) 1.27-9.6). The overall number of attempts [median, 1; interquartile range (IQR), 1-1; range, 1-3 vs. median, 1; IQR, 1-2; range, 1-4; P  = 0.006], use of transfixion technique (12/59 [20.3%] vs. 28/60 [46.7%]; P = 0.002), and overall complication rate (6.8% [4/59] vs. 30.0% [18/60]; P = 0.002) were lower in the smart glasses group than in the control group. However, among paediatric anaesthesiology fellows (CA 5 years), the first- (89.3% [25/28] vs. 80.8% [21/26]; P = 0.619) and second-attempt success rates (96.4% [27/28] vs. 80.8% [21/26]; P = 0.163) did not differ between the two groups.

CONCLUSIONS

Smart glasses-assisted ultrasound guided radial artery catheterisation improved the first attempt success rate among anaesthesiology trainees, reducing the number of attempts and overall complication rates in small paediatric patients. Smart glasses were more effective for anaesthesia residents (CA 2-4 years) but were not effective for paediatric anaesthesiology fellows (CA 5 years).

TRIAL REGISTRATION

ClinicalTrials.gov (NCT05030649; registered 1 September 2021; principal investigator, Prof. Jin-Tae Kim) (https://classic.clinicaltrials.gov/ct2/show/NCT05030649).

Functional bio-inspired hybrid fliers with separated ring and leading edge vortices

Recent advances in passive flying systems inspired by wind-dispersed seeds contribute to increasing interest in their use for remote sensing applications across large spatial domains in the Lagrangian frame of reference. These concepts create possibilities for developing and studying structures with performance characteristics and operating mechanisms that lie beyond those found in nature. Here, we demonstrate a hybrid flier system, fabricated through a process of controlled buckling, to yield unusual geometries optimized for flight. Specifically, these constructs simultaneously exploit distinct fluid phenomena, including separated vortex rings from features that resemble those of dandelion seeds and the leading-edge vortices derived from behaviors of maple seeds. Advanced experimental measurements and computational simulations of the aerodynamics and induced flow physics of these hybrid fliers establish a concise, scalable analytical framework for understanding their flight mechanisms. Demonstrations with functional payloads in various forms, including bioresorbable, colorimetric, gas-sensing, and light-emitting platforms, illustrate examples with diverse capabilities in sensing and tracking.

Comparison of remimazolam and dexmedetomidine for intraoperative sedation in patients undergoing lower extremity surgery under spinal anesthesia: a randomized clinical trial

BACKGROUND

Dexmedetomidine sedation has advantages, such as low incidence of respiratory depression and prolonged block duration, but also significant disadvantages, such as slow onset, high rate of sedation failure, and a long context-sensitive half-life. Remimazolam provides rapid sedation and recovery, high sedation efficacy and has minimal hemodynamic effects. We hypothesized that patients who received remimazolam would require less rescue midazolam than dexmedetomidine.

METHODS

Patients (n=103) scheduled for surgery under spinal anesthesia were randomized to receive dexmedetomidine (DEX group) or remimazolam (RMZ group) targeting a Modified Observer's Assessment of Alertness/Sedation score of 3 or 4. Rescue midazolam was administered if the patient failed to be sedated after the initial loading dose or despite infusion rate adjustment.

RESULTS

Rescue midazolam administration was significantly higher in the DEX group (0% vs 39.2%; p<0.001). Patients in the RMZ group reached the target sedation level more rapidly. The incidences of bradycardia (0% vs 25.5%; p<0.001) and hypertension (0% vs 21.6%; p<0.001) were higher in the DEX group. Respiratory depression occurred at a higher rate in the RMZ group (21.2% vs 2.0%; p=0.002), but no patients required manual ventilation. Patients in the RMZ group recovered faster, had a shorter PACU stay and higher satisfaction scores. Hypotensive episodes in the PACU were more frequent in the DEX group (1.9% vs 29.4%; p<0.001).

CONCLUSIONS

Remimazolam showed excellent sedation efficacy, minimal hemodynamic effects, and fewer adverse events in the PACU than dexmedetomidine. However, it is important to note that respiratory depression was more frequent with the use of remimazolam.

TRIAL REGISTRATION NUMBER

NCT05447507.

Realism of Tactile Texture Playback: A Combination of Stretch and Vibration

This study investigates the effects of two stimulation modalities (stretch and vibration) on natural touch sensation on the volar forearm. The skin-textile interaction was implemented by scanning three textures across the left forearm. The resulting skin displacements were recorded by the digital image correlation technique to capture the information imparted by the textures. The texture recordings were used to create three playback modes (stretch, vibration, and both), which were reproduced on the right forearm. Two psychophysical experiments compared the texture scans to rendered texture playbacks. The first experiment used a matching task and found that to maximize perceptual realism, i.e., similarity to a physical reference, subjects preferred the rendered texture to have a playback intensity of 1X-2X higher on DC components (stretch), and 1X-3.5X higher on AC components (vibration), varying across textures. The second experiment elicited similarity ratings between the texture scans and playbacks and showed that a combination of stretch and vibration was required to create differentiated texture sensations. However, the intensity amplification and use of two stimuli were still insufficient to create fully realistic texture sensations. We conclude that mechanisms beyond single-site uniaxial stimuli are needed to reproduce realistic textural sensations.

Preoperative frailty assessment with ultrasound in elderly patients scheduled for total knee arthroplasty

BACKGROUND

Frailty, a decline in physical and cognitive reserve capacity, renders patients susceptible to various stressors and has been linked to adverse outcomes and increased healthcare utilization. This study aimed to determine whether ultrasound measurements of the rectus abdominis (RA) and biceps brachii (BB) could predict frailty in patients scheduled for total knee arthroplasty.

METHODS

Frailty was assessed using the Clinical Frailty Scale in adults aged ≥60 years. Ultrasound measurements of the rectus abdominis, BB, and quadriceps femoris muscles, along with thigh circumference measurements, were obtained before surgery. The predictive ability of the unadjusted and BMI- and body surface area (BSA)-adjusted measurements were evaluated using receiver operating characteristic curve analysis and area under the curve (AUC) values. Postoperative outcomes, such as admission to the intensive care unit or skilled nursing facility, delirium, falls, re-hospitalization, and 30-day mortality were recorded.

RESULTS

We analyzed data from 148 patients. BB thickness provided a fair prediction of frailty. Average measurements of both BB adjusted for BMI (0.708, 95% CI 0.602-0.814; P<0.001), and BSA (0.708, 95% CI 0.598-0.817; P<0.001) had the highest AUC values. RA muscle measurements could not discriminate frailty. The BMI-adjusted measurements for: right quadriceps femoris thickness (AUC 0.614, 95% CI 0.503-0.725; P=0.044), left thigh circumference (AUC 0.648, 95% CI 0.528-0.769; P=0.016), and average thigh circumference (AUC 0.630, 95% CI 0.511-0.750; P=0.033) had statistically significant but poor AUC values.

CONCLUSIONS

Preoperative ultrasound measurements of the bilateral BB can fairly predict frailty in patients scheduled for total knee arthroplasty.

Ultrasound-guided selective supraclavicular nerve block for postoperative pain control in children receiving Hickman catheter or chemoport insertion: A randomized controlled trial

BACKGROUND

Optimal pain management after insertion of a central venous catheter in children remains unclear.

AIM

This study aimed to evaluate the effects of a selective supraclavicular nerve block on postoperative analgesia in pediatric patients undergoing hickman catheter or chemoport insertion.

METHODS

Fifty patients aged 3-18 years scheduled for elective Hickman or chemoport insertion were randomized into two groups of 25 each: one group received an ultrasound-guided selective supraclavicular nerve block with 0.1 mL/kg of 0.5% ropivacaine (SSCNB group), and the other group did not receive a nerve block (control group). The primary outcome was the postoperative Wong-Baker Faces Pain Rating Scale score measured between 10 and 30 min after surgery. Secondary outcomes included pain scores at 1, 3, and 24 h after the surgery, block-related complications, length of stay in the postanesthesia care unit, postoperative analgesic consumption, and time to first analgesic use 24 h after surgery.

RESULTS

The worst pain score within 30 min in the recovery room was significantly lower in the SSCNB group compared to the control group (6 [5-7] vs. 3 [2-4]; median difference, -3; 95% CI, -4 to -1; p < .001). Pain scores at 1, 3, and 24 h after surgery were also significantly lower in the SSCNB group. The need for both opioid and non-opioid analgesics in the postoperative period was significantly lower in the SSCNB group (36.0% vs. 0%; p = .002 and 44.0% vs. 16.0%; mean difference, -28%; 95% CI, -56 to 0.19; p = .033, respectively), while other secondary outcomes were not significantly different between the two groups.

CONCLUSIONS

Ultrasound-guided SSCNB is an effective method for managing postoperative pain in children undergoing Hickman catheter or chemoport insertion, reducing the need for analgesics within 24 h after surgery.

Handheld ultrasound-assisted versus palpation-guided combined spinal-epidural for labor analgesia: a randomized controlled trial

Preprocedural ultrasound assistance can enhance the efficacy of neuraxial anesthesia in obstetrics. We investigated whether the use of handheld ultrasound can shorten the procedural time of labor combined spinal-epidural (CSE) analgesia compared with conventional landmark-guided methods. Eighty-four women requesting labor analgesia were randomly assigned to either handheld ultrasound-assisted or palpation-guided CSE analgesia. Primary outcome was procedure time of the CSE analgesia. Secondary outcomes included identification time, performance time, number of needle manipulations required for epidural/spinal success, first-attempt success rate, periprocedural pain scores, the incidence of accidental dural puncture, and patient satisfaction. Total procedure time did not significantly differ between the ultrasound and palpation groups (median [IQR], 191.5 [167-224] vs. 204.5 [163-358] s; P = 0.442). However, the performance time was significantly shorter in the ultrasound group (134.5 [115-177] vs. 183 [129-296] s; P = 0.011), although identification time was longer in the ultrasound group (53 [41-72] vs. 30.5 [21-45] s; P < 0.001). The epidural success rate at first insertion attempt was higher in the ultrasound group (85.7% vs. 59.5%, P = 0.014). Preprocedural handheld ultrasound assistance resulted in equivalent total procedure times but reduced performance times and higher first-attempt success rates. Therefore, clinicians may consider this technique for labor CSE analgesia.Trial registration: NCT04759547.

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.

Changes in diaphragmatic ultrasonography findings and their association with postoperative complications in children undergoing pulmonary resection: A single-centre, prospective, observational study

BACKGROUND

Few studies have investigated the changes in diaphragmatic function and their association with postoperative pulmonary complications (PPCs) in paediatric patients after lung resection.

OBJECTIVE

This study aimed to evaluate diaphragmatic function using ultrasound after lung resection and its influence on PCCs in children.

DESIGN

Prospective observational study.

SETTING

A tertiary children's hospital.

PATIENTS

Children aged 6 years or less who were scheduled for video-assisted thoracoscopic lung resection.

INTERVENTION

Ultrasonographic measurements of diaphragmatic excursion (DE) and thickening fraction (TF) were performed for three epochs: before anaesthesia induction (T0), 1 h postoperatively (T1) and 24 h postoperatively (T2). The thickening fraction is calculated from the thickness of the diaphragm at end expiration and end inspiration at each time point. DE T1 /DE T0 , DE T2 /DE T0 , TF T1 /TF T0 and TF T2 /TF T0 (%) were calculated. The incidence of PCCs was also determined.

MAIN OUTCOME MEASURES

The primary outcomes were changes in diaphragmatic excursion and thickening fraction over time, from T0 to T2. The secondary outcomes were the association between ultrasound parameters of diaphragm function and the occurrence of early PPCs within 3 days.

RESULTS

Data from 74 children were analysed. On the operated side, both diaphragmatic excursion and thickening fraction decreased at T1 and recovered slightly at T2, and were significantly lower than the T0 values. Children with PPCs had significantly lower DE T2 /DE T0 and TF T2 /TF T0 scores on the operated side than those without PPCs. According to the receiver operating characteristic analysis, the DE T2 /DE T0 (< 61.1%) on the operated side was associated with PPCs with an area under the curve of 0.764.

CONCLUSIONS

Peri-operative diaphragmatic function assessed by ultrasonography changed after lung resection in children. The diaphragmatic excursion and thickening fraction decreased postoperatively, and a prolonged decrease in diaphragmatic excursion was associated with pulmonary complications after lung surgery in children.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov, NCT04400370.

Higher portal venous pulsatility is associated with worse clinical outcomes following congenital heart surgery: a single-centre prospective cohort study

PURPOSE

Increased portal venous flow pulsatility is associated with major complications after adult cardiac surgery. Nevertheless, no data are available for pediatric patients with congenital heart disease. We hypothesized that Doppler parameters including portal flow pulsatility could be associated with postoperative outcomes in children undergoing various cardiac surgeries.

METHODS

We conducted a prospective observational cohort study in children undergoing congenital cardiac surgery. We obtained postoperative portal, splenic, and hepatic venous Doppler data and perioperative clinical data including major postoperative complications. Portal and splenic venous flow pulsatility were calculated. We evaluated the association between venous Doppler parameters and adverse outcomes. The primary objective was to determine whether postoperative portal flow pulsatility could indicate major complications following congenital heart surgery.

RESULTS

In this study, we enrolled 389 children, 74 of whom experienced major postoperative complications. The mean (standard deviation) portal pulsatility (44 [30]% vs 25 [14]%; 95% confidence interval [CI] for mean difference, 12 to 26; P < 0.001] and splenic pulsatility indices (41 [30]% vs 26 [16]%; 95% CI, 7 to 23; P < 0.001) were significantly higher in children with postoperative complications than in those without complications. The portal pulsatility index was able to help identify postoperative complications in biventricular patients and univentricular patients receiving bidirectional cavopulmonary shunt whereas it did not in other univentricular patients. An increased postoperative portal pulsatility index was significantly associated with major complications after pediatric cardiac surgery (odds ratio, 1.40; 95% CI, 1.29 to 1.91; P < 0.001).

CONCLUSIONS

Higher portal venous pulsatility is associated with major postoperative complications in children undergoing cardiac surgery. Nevertheless, more data are needed to conclude the efficacy of portal venous pulsatility in patients with univentricular physiology.

STUDY REGISTRATION

ClinicalTrials.gov (NCT03990779); registered 19 June 2019.

The physical origin of aneurysm growth, dissection, and rupture

Rupture of aortic aneurysms is by far the most fatal heart disease, with a mortality rate exceeding 80%. There are no reliable clinical protocols to predict growth, dissection, and rupture because the fundamental physics driving aneurysm progression is unknown. Here, via in-vitro experiments, we show that a blood-wall, fluttering instability manifests in synthetic arteries under pulsatile forcing. We establish a phase space to prove that the transition from stable flow to unstable aortic flutter is accurately predicted by a flutter instability parameter derived from first principles. Time resolved strain maps of the evolving system reveal the dynamical characteristics of aortic flutter that drive aneurysm progression. We show that low level instability can trigger permanent aortic growth, even in the absence of material remodeling. Sufficiently large flutter beyond a secondary threshold localizes strain in the walls to the length scale clinically observed in aortic dissection. Lastly, significant physical flutter beyond a tertiary threshold can ultimately induce aneurysm rupture via failure modes reported from necropsy. Resolving the fundamental physics of aneurysm progression directly leads to clinical protocols that forecast growth as well as intercept dissection and rupture by pinpointing their physical origin.

Effect of tidal volume change on pressure-based prediction of fluid responsiveness in children

INTRODUCTION

It is known that pulse pressure variation and systolic pressure variation cannot predict fluid responsiveness in children. In adults, the ability of these dynamic parameters to predict fluid responsiveness is improved by increasing tidal volume. We planned to investigate whether pulse pressure variation or systolic pressure variation can predict fluid responsiveness in children when augmented by increasing tidal volume by conducting a prospective study.

METHODS

We enrolled children younger than 7 years who underwent cardiac surgery for atrial septal defect or ventricular septal defect. After sternum closure, pulse pressure variation and systolic pressure variation were continuously recorded while changing the tidal volume to 6, 10, and 14 mL/kg. Fluid loading was done with 10 mL/kg of crystalloids for 10 min, and stroke volume index was measured via transesophageal echocardiography. Children whose stroke volume index increased by more than 15% after the fluid loading were defined as responders to fluid therapy. We set primary outcome as the predictability of pulse pressure variation and systolic pressure variation for fluid responsiveness and measured the area under the curve of receiver operating characteristics curve.

RESULTS

Twenty-six children were included, of which 15 were responders. At the tidal volume of 14 mL/kg, the area under the curves of receiver operating characteristics curves of pulse pressure variation and systolic pressure variation were 0.576 (p = .517) and 0.548 (p = .678), respectively. The differences in dynamic parameters between responders and nonresponders were not significant.

DISCUSSION

Failure of pulse pressure variation or systolic pressure variation at augmented tidal volume in children may be due to difference in their arterial compliance from those of adults. Large compliance of thoracic wall may be another reason.

CONCLUSIONS

Augmented pulse pressure variation or systolic pressure variation due to increased tidal volume cannot predict fluid responsiveness in children after simple cardiac surgery.

The effect of goal-directed hemodynamic therapy on clinical outcomes in patients undergoing radical cystectomy: a randomized controlled trial

BACKGROUND

This study investigated the effects of intraoperative goal-directed hemodynamic therapy (GDHT) on postoperative outcomes in patients undergoing open radical cystectomy.

METHODS

This prospective, single-center, randomized controlled trial included 82 patients scheduled for open radical cystectomy between September 2018 and November 2021. The GDHT group (n = 39) received the stroke volume index- and cardiac index-based hemodynamic management using advanced hemodynamic monitoring, while the control group (n = 36) received the standard care under the discretion of attending anesthesiologists during surgery. The primary outcome was the incidence of a composite of in-hospital postoperative complications during hospital stays.

RESULTS

A total of 75 patients were included in the final analysis. There was no significant difference in the incidence of in-hospital postoperative complications (28/39 [71.8%] vs. 30/36 [83.3%], risk difference [95% CI], -0.12 [-0.30 to 0.07], P = 0.359) between the groups. The amounts of intraoperative fluid administered were similar between the groups (2700 [2175-3250] vs. 2900 [1950-3700] ml, median difference [95% CI] -200 [-875 to 825], P = 0.714). The secondary outcomes, including the incidence of seven major postoperative complications, duration of hospital stay, duration of intensive care unit stay, and grade of complications, were comparable between the two groups. Trends in postoperative estimated glomerular filtration rate, serum creatinine, and C-reactive protein did not differ significantly between the two groups.

CONCLUSIONS

Intraoperative GDHT did not reduce the incidence of postoperative in-hospital complications during the hospital stay in patients who underwent open radical cystectomy.

TRIAL REGISTRATION

This study was registered at http://www.

CLINICALTRIALS

gov (Registration number: NCT03505112; date of registration: 23/04/2018).

Usefulness of C-curved stylet for intubation with the C-MAC® Miller videolaryngoscope in neonates and infants: a prospective randomized controlled trial

BACKGROUND

Optimizing endotracheal tube (ETT) shape is important for successful videolaryngoscope-aided intubation. This prospective randomized controlled study aimed to compare the tube-handling time between a C-curved and hockey stick-shaped stylet in infants and neonates using the C-MAC® videolaryngoscope Miller blade.

METHODS

A total of 110 infants (age < 1 year) were randomly assigned to either the hockey stick-curved stylet group (group H, n = 53) or the C-curved stylet group (group C, n = 57). The primary outcome was tube handling time after glottis visualization and the secondary outcomes were the total intubation time, incidence of successful intubation, initial tube tip location at the laryngeal inlet, and numerical rating scale for ease of intubation.

RESULTS

Tube insertion time and total intubation duration (both in seconds) were significantly shorter in group C than in group H (13.3 ± 8.9 vs. 25.1 ± 27.0, P = 0.002; 19.9 ± 9.4 vs. 32.8 ± 27.1, P = 0.001, respectively). Group C displayed a higher rate of intubation success within 30 s than group H (87.7% vs. 69.8%, P = 0.029). The initial tube tip was located at the center in 34 children in group C (59.6%) and 12 children in group H (26.1%, P < 0.001). Laryngoscope operators rated intubation as easier when provided with a C-curved stylet.

CONCLUSIONS

In neonates and infants, modification of the ETT shape into a C-curve may reduce tube handling time compared to the conventional hockey stick-shaped tube during intubation using a C-MAC® video laryngoscope Miller blade.

Comparison between low-volume local anesthetic with intravenous dexamethasone and conventional volume without dexamethasone for superior trunk block after arthroscopic shoulder surgery: a randomized controlled non-inferiority trial

INTRODUCTION

This study aimed to investigate whether low-volume local anesthetic with intravenous dexamethasone can reduce the incidence of diaphragmatic paresis while maintaining the analgesic duration compared with conventional volume of local anesthetic without intravenous dexamethasone when performing ultrasound-guided superior trunk block in patients undergoing arthroscopic shoulder surgery.

METHODS

Eighty-four adult patients undergoing arthroscopic shoulder surgery under general anesthesia were randomly assigned to receive ultrasound-guided superior trunk block using 7 mL of 0.5% ropivacaine with 0.15 mg/kg of intravenous dexamethasone (treatment group), or 15 mL of 0.5% ropivacaine with intravenous normal saline (control group). The co-primary outcomes were (1) the duration of analgesia (time between block completion and onset of surgical pain with a Numeric Rating Scale pain score of 4 or higher), which was compared against a non-inferiority margin of 3 hours, and (2) the incidence of diaphragmatic paresis evaluated using M-mode ultrasonography in the post-anesthesia care unit.

RESULTS

The mean duration of analgesia was 12.4 (6.8) and 11.2 (4.6) hours in the treatment and control groups, respectively (mean difference: -1.2 hours; 95% CI -3.8 to 1.3]; p for non-inferiority<0.001), meeting the non-inferiority criteria. The incidence of diaphragmatic paresis was 45.2% and 85.4% in the treatment and control groups, respectively (relative risk: 0.53; 97.5% CI 0.35 to 0.80; p<0.001).

CONCLUSIONS

Superior trunk block using low-volume local anesthetic with intravenous dexamethasone can reduce the incidence of diaphragmatic paresis while providing non-inferior analgesic duration compared with the conventional volume of local anesthetic in patients undergoing arthroscopic shoulder surgery.

TRIAL REGISTRATION NUMBER

Clinical Research Information Service of Republic of Korea Registry (KCT0005998).

Anterior quadratus lumborum block for analgesia after living-donor renal transplantation: a double-blinded randomized controlled trial

INTRODUCTION

Limited non-opioid analgesic options are available for managing postoperative pain after renal transplantation. We aimed to investigate whether the unilateral anterior quadratus lumborum (QL) block would reduce postoperative opioid consumption after living-donor renal transplantation in the context of multimodal analgesia.

METHODS

Eighty-eight adult patients undergoing living-donor renal transplantation were randomly allocated to receive the unilateral anterior QL block (30 mL of ropivacaine 0.375%) or sham block (normal saline) on the operated side before emergence from anesthesia. All patients received standard multimodal analgesia, including the scheduled administration of acetaminophen and fentanyl via intravenous patient-controlled analgesia. The primary outcome was the total opioid consumption during the first 24 hours after transplantation. The secondary outcomes included pain scores, time to first opioid administration, cutaneous distribution of sensory blockade, motor weakness, nausea/vomiting, quality of recovery scores, time to first ambulation, and length of hospital stay.

RESULTS

The total opioid consumption in the first 24 hours after transplantation did not differ significantly between the intervention and control groups (median (IQR), 160.5 (78-249.8) vs 187.5 (93-309) oral morphine milligram equivalent; median difference (95% CI), -27 (-78 to 24), p=0.29). No differences were observed in the secondary outcomes.

CONCLUSIONS

The anterior QL block did not reduce opioid consumption in patients receiving multimodal analgesia after living-donor renal transplantation. Our findings do not support the routine administration of the anterior QL block in this surgical population.

TRIAL REGISTRATION NUMBER

NCT04908761.

Association of the perfusion index with postoperative acute kidney injury: a retrospective study

BACKGROUND

Many studies have examined the risk factors for postoperative acute kidney injury (AKI), but few have focused on intraoperative peripheral perfusion index (PPI) that has recently been shown to be associated with postoperative morbidity and mortality. Therefore, this study aimed to evaluate the relationship between intraoperative PPI and postoperative AKI under the hypothesis that lower intraoperative PPI is associated with AKI occurrence.

METHODS

We retrospectively searched electronic medical records to identify patients who underwent surgery at the general surgery department from May 2021 to November 2021. Patient baseline characteristics, pre- and post-operative laboratory test results, comorbidities, intraoperative vital signs, and discharge profiles were obtained from the Institutional Clinical Data Warehouse and VitalDB. Intraoperative PPI was the primary exposure variable, and the primary outcome was postoperative AKI.

RESULTS

Overall, 2,554 patients were identified and 1,586 patients were included in our analysis. According to Kidney Disease Improving Global Outcomes (KDIGO) criteria, postoperative AKI occurred in 123 (7.8%) patients. We found that risks of postoperative AKI increased (odds ratio: 2.00, 95% CI [1.16, 3.44], P = 0.012) when PPI was less than 0.5 for more than 10% of surgery time. Other risk factors for AKI occurrence were male sex, older age, higher American Society of Anesthesiologists physical status, obesity, underlying renal disease, prolonged operation time, transfusion, and emergent operation.

CONCLUSIONS

Low intraoperative PPI was independently associated with postoperative AKI.

Influence of laminectomy on the lumbosacral cerebrospinal fluid volume: A retrospective magnetic resonance imaging study

The cerebrospinal fluid volume affects the block height of spinal anaesthesia. Laminectomy of the lumbar spine may result in increased lumbosacral cerebrospinal fluid volume. This study aimed to test the hypothesis that the lumbosacral cerebrospinal fluid volume of patients with a history of lumbar laminectomy would be larger than that of patients with normal lumbar spine anatomy using magnetic resonance imaging. Lumbosacral spine magnetic resonance images of 147 patients who underwent laminectomy at the L2 vertebrae or below (laminectomy group) and 115 patients without a history of spinal surgery (control group) were retrospectively reviewed. The lumbosacral cerebrospinal fluid volumes between the L1-L2 intervertebral disc level and the end of the dural sac were measured and compared between the two groups. The mean (standard deviation) lumbosacral cerebrospinal fluid volume was 22.3 (7.8) ml and 21.1 (7.4) ml in the laminectomy and control groups, respectively (mean difference 1.2 ml; 95% confidence interval -0.7 to 3.0 ml; P = 0.218). In the prespecified subgroup analysis according to the number of laminectomy levels, patients who underwent more than two levels of laminectomy exhibited slightly larger lumbosacral cerebrospinal fluid volume (n = 17, 30.5 (13.5) ml) compared with those who underwent two (n = 40, 20.7 (5.6) ml; P = 0.014) or one level of laminectomy (n = 90, 21.4 (6.2) ml; P = 0.010) and the control group (21.1 (7.4) ml; P = 0.012). In conclusion, the lumbosacral cerebrospinal fluid volume did not differ between patients who underwent lumbar laminectomy and those without a history of laminectomy. However, patients who underwent laminectomy at more than two levels had a slightly larger volume of lumbosacral cerebrospinal fluid than those who underwent less extensive laminectomy and those without a history of lumbar spine surgery. Further studies are warranted to confirm the subgroup analysis findings and elucidate the clinical implications of such differences in the lumbosacral cerebrospinal fluid volume.

Comparison of effects of volatile and intravenous anesthetics on pupillary function during general anesthesia in children: A prospective observational study

BACKGROUND

The light reflex, which reflects central nervous system dysfunction, can also be affected by anesthetic agents.

AIMS

We evaluated whether these effects differed according to the anesthetic agent in pediatric patients.

METHODS

Twenty children aged 3-12 years who were scheduled to undergo elective surgery under general anesthesia were randomly allocated to propofol and sevoflurane groups and underwent pupillometric assessments at five points during anesthesia: T1, after confirming loss of consciousness; T2, after endotracheal intubation; T3, at the time of skin incision; T4, 1 h after skin incision; and T5, before endotracheal extubation. The primary outcome was the Neurological Pupil index at T4, and the secondary outcomes were other pupillometric parameters, including pupil diameter, percentage of change in pupil diameter, dilation velocity, and constriction velocity.

RESULTS

At T4, the Neurological Pupil index was significantly lower in the sevoflurane group (median difference, 0.30; 95% CI, 0.00 to 0.70; p = .036). Furthermore, the Neurological Pupil index at all time points was lower in the sevoflurane group. The time-and-group interaction effects on constriction velocity and dilation velocity were significantly different [F(1, 4) = 16.68, p = .002; F(1, 4) = 14.78, p = .008, respectively] but were not different on the Neurological Pupil index, pupil diameter, and percentage of change in pupil diameter. No intergroup differences were observed in the baseline characteristics, the flow rate of remifentanil at each time point, and total infused remifentanil.

CONCLUSION

The Neurological Pupil index value in pediatric patients under general anesthesia is affected by the anesthetic agent used; this factor requires consideration in evaluations of the Neurological Pupil index during general anesthesia.

Evaluation of Portal, Splenic, and Hepatic Vein Flows in Children Undergoing Congenital Heart Surgery

OBJECTIVE

Little is known about changes in portal, splenic, and hepatic vein flow patterns in children undergoing congenital heart surgery. This study aimed to determine the characteristics of portal, splenic, and hepatic vein flow patterns using ultrasonography in children undergoing cardiac surgery.

DESIGN

Single-center, prospective observational study.

SETTING

Tertiary children's hospital, operating room.

PARTICIPANTS

Children undergoing cardiac surgery.

MEASUREMENT AND MAIN RESULTS

The authors obtained ultrasound data from the heart, inferior vena cava, portal, splenic, and hepatic veins before and after surgeries. In the biventricular group, which included children with atrial and ventricular septal defects and pulmonary stenosis (n = 246), the portal pulsatility index decreased from 38.7% to 25.6% (p < 0.001) after surgery. The preoperative portal pulsatility index was significantly higher in patients with pulmonary hypertension (43.3% v 27.4%; p < 0.001). In the single-ventricle group (n = 77), maximum portal vein flow velocities of Fontan patients were significantly lower (13.5 cm/s) compared with that of patients with modified Blalock-Taussig shunt (19.7 cm/s; p = 0.035) or bidirectional cavopulmonary shunt (23.1 cm/s; p < 0.001). The cardiac index was inversely correlated with the portal pulsatility index in the bidirectional cavopulmonary shunt and Fontan circulation. (β = -5.693, r² = 0.473; p = 0.001) The portal pulsatility index was correlated with splenic venous pulsatility and hepatic venous atrial reverse flow velocity in biventricular and single-ventricle groups.

CONCLUSIONS

The characteristics of venous Doppler patterns in the portal, splenic, and hepatic veins differed according to congenital heart disease. Further studies are required to determine the association between splanchnic venous Doppler findings and clinical outcomes in this population.

Pharmacokinetics of dexmedetomidine in pediatric patients undergoing cardiac surgery with cardiopulmonary bypass

BACKGROUND

Cardiopulmonary bypass can affect the pharmacokinetics of anesthetic agents.

AIMS

We aimed to evaluate the pharmacokinetics of dexmedetomidine for infants and small children undergoing cardiac surgery with cardiopulmonary bypass based on population pharmacokinetics.

METHODS

We enrolled 30 pediatric cardiac surgical patients in this study. After anesthetic induction with atropine (0.02 mg/kg), thiopental sodium (5 mg/kg), and fentanyl (2-3 μg/kg), we administered 1 μg/kg of dexmedetomidine for 10 min, followed by administration of 0.5 μg/kg of dexmedetomidine per hour during surgery. At the initiation of cardiopulmonary bypass, 1 μg/kg of dexmedetomidine was infused over 5 min. Arterial blood was obtained at predefined time points. A pharmacokinetic model was developed using NONMEM. Theory-based allometric scaling with fixed exponents was applied. Weight, age, post-menstrual age, fat-free mass, whether to implement cardiopulmonary bypass and temperature were explored as covariates.

RESULTS

A total of 376 blood samples were obtained from 29 children (age: 20.3 ± 19.3 months, weight: 9.7 ± 4.1 kg). A two-compartment mammillary model with third compartment associated cardiopulmonary bypass procedure best explained the pharmacokinetics of dexmedetomidine. The pharmacokinetic parameter estimates (95% CI) standardized to a 70-kg person were as follows: V₁ (L) = 31.6 (17.9-39.5), V₂ (L) = 90.1 (44.0-330), Cl (L/min) = 1.08 (0.70-1.25), Q (L/min) = 2.0 (1.05-3.46). Volume for third compartment associated cardiopulmonary bypass procedure (L) = 39.4 (19.3-50.9). Clearance was not influenced by the presence of cardiopulmonary bypass in this model.

CONCLUSION

When cardiopulmonary bypass is applied, the plasma concentration of dexmedetomidine decreases due to an increase in the volume of distribution, so a loading dose is required to maintain the previous concentration.

Effect of real-time binaural music on sedation with dexmedetomidine during spinal anesthesia: A triple-arm, assessor-blind, randomized controlled trial

STUDY OBJECTIVE

Binaural audio induces sedation and reduces pain and anxiety in surgical patients. This study tested the hypothesis that dexmedetomidine requirement for adequate sedation during spinal anesthesia would be lower in patients listening to music with binaural sound than that in patients listening to plain or no music.

DESIGN

A triple-arm, assessor-blind, randomized controlled study.

SETTING

Operating room.

PATIENTS

One hundred and eighty-nine patients undergoing orthopedic surgery under spinal anesthesia.

INTERVENTIONS

Patients were randomly assigned to music with binaural sound, plain music, or no music groups. Dexmedetomidine was infused for sedation during surgery. The loading infusion rate was 6 μg/kg predicted body weight (PBW)/h, followed by continuous infusion at 0.6 μg/kg PBW/hr. Loading was stopped after achieving adequate sedation, defined as the Observer's Assessment of Alertness/Sedation (OAA/S) scale score of 3. Infusion rate was adjusted every 30 min per the OAA/S scale.

MEASUREMENTS

Primary outcomes were the difference in the dexmedetomidine loading dose adjusted for the patient's PBW between (1) the binaural and plain music groups and (2) the binaural and control groups. Secondary outcomes were the total dose and total loading time of dexmedetomidine; Patient State Index; relative powers of the alpha, theta, and delta bands; recovery from sedation; and patient satisfaction score.

MAIN RESULTS

The final analyses included 184 patients. The PBW-adjusted dexmedetomidine loading dose was significantly lower in patients listening to music with binaural sound (1.15 ± 0.30 μg/kg PBW) than that in patients without music (1.33 ± 0.33 μg/kg PBW; mean difference, 0.18 μg/kg PBW; 95% confidence interval [CI], 0.06 to 0.29; P = 0.002). However, the difference was not statistically significant when compared with the plain music group (1.26 ± 0.36 μg/kg PBW; mean difference, 0.11 μg/kg PBW; 95% CI, -0.01 to 0.23; P = 0.070). Dexmedetomidine total dose, recovery from sedation, and patient satisfaction score showed no difference among the three groups.

CONCLUSIONS

Compared with no music, music with binaural sound reduced the dexmedetomidine loading dose; however, this sedative-sparing effect of binaural sound was not found when compared to plain music.

Effect of Tulobuterol Patch Versus Placebo on the Occurrence of Respiratory Adverse Events in Children Undergoing Tonsillectomies: A Randomized Controlled Trial

BACKGROUND

Perioperative respiratory adverse events are common in children. We aimed to evaluate the effect of the transdermal β-2 agonist, tulobuterol, compared with that of placebo on the incidence of perioperative respiratory adverse events in pediatric patients undergoing tonsillectomy.

METHODS

In this triple-blinded (patient, anesthesia provider, and outcome assessor) randomized controlled trial, 188 patients were randomly allocated to receive tulobuterol or a placebo. The tulobuterol groups received a tulobuterol patch (1 mg) masked with a bandage, whereas the placebo only received the bandage. The assigned bandage was applied to the patients 8 to 10 hours before the surgery. The primary outcome was the occurrence of any perioperative respiratory adverse events: oxygen desaturation <95%, airway obstruction, laryngospasm, bronchospasm, severe coughing, or stridor. The outcomes were evaluated using the average relative effect test, which estimates the effect of individual components of a composite outcome and then averages effects across components.

RESULTS

A total of 88 and 94 patients who received tulobuterol and placebo, respectively, were analyzed. The incidence of any perioperative respiratory adverse event was lower with tulobuterol (n = 13/88; 14.7%) than that with the placebo (n = 40/94; 42.5%), with an estimated average relative risk (95% confidence interval) across components of 0.35 (0.20-0.60; P < .001). The symptoms of airway obstruction were lower with tulobuterol (n = 8/88; 9.0%) than that with the placebo (n = 32/94; 34.0%), with relative risk (95% CI) of 0.31 (0.17-0.56; P < .001). The occurrence of severe coughing was lower with tulobuterol (n = 1/88; 1.1%) than that with the placebo (n = 8/94; 8.5%), with relative risk (95% CI) of 0.15 (0.03-0.68; P = .014).

CONCLUSIONS

In preschool children undergoing tonsillectomy, the preoperative application of a tulobuterol patch could decrease the occurrence of perioperative respiratory adverse events. Further studies are needed to elucidate the effect of the tulobuterol patch in a broad spectrum of pediatric anesthesia.

Two-center randomized controlled trial comparing oral chloral hydrate and intranasal combination of dexmedetomidine and ketamine for procedural sedation in children: study protocol

BACKGROUND

Oral chloral hydrate is widely used in pediatric sedation. Intranasal dexmedetomidine has been increasingly used for pediatric sedation; however, its improvement is warranted. The combination of dexmedetomidine with ketamine can improve onset and hemodynamic stability while maintaining sedative efficacy. This study aims to determine the efficacy and safety of intranasal combination of dexmedetomidine and ketamine compared to oral chloral hydrate.

METHODS

This is a prospective, parallel-arm, single-blinded, two-center, superiority randomized controlled trial with 1:1 allocation, designed to compare the effects of intranasal combination of dexmedetomidine and ketamine with those of oral chloral hydrate. We shall enroll 136 patients aged < 7 years old in this study. Prior to the procedure, we shall randomize each patient into the control group (oral chloral hydrate 50 mg/kg) or study group (intranasal dexmedetomidine 2 μg/kg and ketamine 3 mg/kg). The primary outcome will be the rate of achieving an adequate sedation level (6-point Pediatric Sedation State Scale 1, 2, or 3) within 15 min. In addition, we shall measure the sedation time, sedation failure rate, completion of procedure, adverse events, patient acceptance, and physician satisfaction.

DISCUSSION

This study will provide evidence of the efficacy and safety of the intranasal combination of dexmedetomidine and ketamine in comparison with oral chloral hydrate.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT04820205. Registered on 19th March 2021.

Conventional reversal of rocuronium-induced neuromuscular blockade by sugammadex in Korean children: pharmacokinetics, efficacy, and safety analyses

Background: Sugammadex is known to reverse neuromuscular blockade induced by non-depolarizing agents. In children, the recommended dose for reversal of moderate neuromuscular blockade is 2 mg/kg. We investigated the pharmacokinetics and pharmacodynamics of sugammadex in Korean children. Methods: Children (2-17 years of age) undergoing brain or spine surgery were enrolled and randomly assigned to control (neostigmine) and 2, 4, or 8 mg/kg sugammadex groups. Following induction of anesthesia and monitoring of the response to train-of-four stimulation, 1 mg/kg rocuronium was intravenously administered. Upon reappearance of the second twitch to train-of-four stimulation, the study drug was administered according to group allocation. The plasma concentrations of rocuronium and sugammadex were serially measured at nine predefined time points following study drug administration. To determine efficacy, we measured the time elapsed from drug administration to recovery of T₄/T₁ ≥ 0.9. For pharmacokinetics, non-compartmental analysis was performed and we monitored adverse event occurrence from the time of study drug administration until 24 h post-surgery. Results: Among the 29 enrolled participants, the sugammadex (2 mg/kg) and control groups showed recovery times [median (interquartile range)] of 1.3 (1.0-1.9) and 7.7 (5.3-21.0) min, respectively (p = 0.002). There were no significant differences in recovery time among the participants in sugammadex groups. The pharmacokinetics of sugammadex were comparable to those of literature findings. Although two hypotensive events related to sugammadex were observed, no intervention was necessary. Conclusion: The findings of this pharmacokinetic analysis and efficacy study of sugammadex in Korean children indicated that sugammadex (2 mg/kg) may be safely administered for reversing moderate neuromuscular blockade. Some differences in pharmacokinetics of sugammadex were observed according to age. Clinical Trial Registration: http://clinicaltrials.gov (NCT04347486).

Biodegradable, three-dimensional colorimetric fliers for environmental monitoring

Recently reported winged microelectronic systems offer passive flight mechanisms as a dispersal strategy for purposes in environmental monitoring, population surveillance, pathogen tracking, and other applications. Initial studies indicate potential for technologies of this type, but advances in structural and responsive materials and in aerodynamically optimized geometries are necessary to improve the functionality and expand the modes of operation. Here, we introduce environmentally degradable materials as the basis of 3D fliers that allow remote, colorimetric assessments of multiple environmental parameters-pH, heavy metal concentrations, and ultraviolet exposure, along with humidity levels and temperature. Experimental and theoretical investigations of the aerodynamics of these systems reveal design considerations that include not only the geometries of the structures but also their mass distributions across a range of bioinspired designs. Preliminary field studies that rely on drones for deployment and for remote colorimetric analysis by machine learning interpretation of digital images illustrate scenarios for practical use.

Learning curve of fiberoptic-guided tracheal intubation through supraglottic airway device for pediatric airway management: a manikin study

Background

Although fiberoptic-guided endotracheal intubation using a supraglottic airway device is a good alternative for the management of difficult airways, its learning curve for residents has not been evaluated in pediatric patients. We aimed to train residents using a pediatric manikin and obtain learning curves for the procedure to evaluate the efficiency of the training.

Methods

We conducted a single-armed prospective study with anesthesiology residents. Plain endotracheal tube intubation guided by a fiberoptic bronchoscope through Ambu® AuraGainTM was demonstrated in a pediatric manikin to the participants before training. The procedure was divided into four steps: supraglottic airway device insertion, vocal cord identification, carina identification, and endotracheal tube insertion into the trachea. The results and elapsed procedure times of each trial were recorded. The learning curves for the participants were constructed and analyzed using the cumulative sum method.

Results

All of the 30 participants acquired proficiency at the end of the practice between eight and 25 trials. The overall success rate for the procedure was 92.8%, and above 80% for all participants. Mean (±SD) procedure time was 71.3 (±50.7) s. The 4th step accounted for 86.2% of total failures and 48.0% of the total procedure time. The procedure time rapidly decreased in the 2nd trial, and a modest decline was observed thereafter.

Conclusions

Anesthesiology residents obtained proficiency within 25 times of practice for fiberoptic-guided intubation in a pediatric manikin through an AuraGain supraglottic airway device with acceptable success rate and procedure time. The procedure time markedly decreased following the first experience.

Response of internal carotid artery blood flow velocity to fluid challenge under general anesthesia in pediatric patients with moyamoya disease: A prospective observational study

BACKGROUND

Maintaining cerebral blood flow is important in intraoperative management of moyamoya disease patients.

AIMS

To access changes in the carotid artery blood flow velocity in response to fluid challenge, blood pressure, and cardiac output under general anesthesia in pediatric patients with moyamoya disease.

METHODS

This observational study included pediatric patients with moyamoya disease undergoing general anesthesia for encephaloduroarteriosynangiosis. Each patient underwent an ultrasound assessment thrice as follows: after anesthetic induction (T1), after fluid challenge (10 ml/kg, T2), and at the end of surgery (T3). The primary outcome was the change in the internal carotid artery blood flow velocity after fluid challenge and was assessed using a paired t-test. The secondary outcomes comprised changes in the internal, external, and common carotid artery blood flow peak velocities after fluid challenge and the factors influencing these changes.

RESULTS

We enrolled and analyzed 30 patients with a mean age of 7.2 years. After fluid challenge, the systolic (p = .003) and mean blood pressure (p = .017), stroke volume index (p = .008), and cardiac index (p = .140) were higher than those at T1. However, both internal carotid artery blood flow velocities did not change after fluid challenge (p = .798, mean difference and 95% confidence interval [CI], -1.1 and -10.3 to 8.0 for right, p = .164, mean difference and 95% CI, -5.2 and -12.7 to 2.2 for left). The internal carotid artery blood flow velocity was correlated with the cardiac index, stroke volume index, and mean and diastolic blood pressure, with low significance.

CONCLUSIONS

The internal carotid artery blood flow velocity did not increase in pediatric patients with moyamoya disease under general anesthesia, despite fluid challenge and corresponding changes in the blood pressure and cardiac output. Intraoperative hemodynamic management to improve the cerebral blood flow in these patients requires further investigation.

Validation of the Masimo O3™ regional oximetry device in pediatric patients undergoing cardiac surgery

We assessed the accuracy of Masimo O3™ regional cerebral oxygen saturation (rSO₂) readings by comparing them with reference values and evaluated the relationship between rSO₂ and somatic tissue oxygen saturation (StO₂) in children undergoing cardiac surgery. After anesthesia induction, pediatric sensors were applied to the forehead and foot sole, and rSO₂ and StO₂ values were monitored continuously. Before cardiopulmonary bypass (CPB), F_IO₂ was set to 0.2, 0.5, and 0.8 serially every 15 min. After CPB, F_IO₂ was reversed. The reference values (SavO₂) were calculated by combining arterial (SaO₂) and central venous oxygen saturation (SvO₂) readings from the arterial and central lines, respectively (0.7 [Formula: see text] SvO₂ + 0.3 [Formula: see text] SaO₂). In total, 265 pairs of rSO₂/StO₂ and SavO₂ from 49 patients were analyzed. The bias, standard deviation (SD), standard error (SE), and root mean squared error (RMSE) of rSO₂ were 2.6%, 4.5%, 0.3%, and 4.3%, respectively. The limits of agreement ranged from -6.3% to 11.6%. Trend accuracy analysis yielded a relative mean error of -1.4%, with an SD of 4.3%, SE of 0.2%, and RMSE of 3.9%. According to multiple linear regression analysis, the application of CPB, F_IO₂, Hb level, and tip location of the central venous catheter influenced the bias (all P < 0.05). Furthermore, the correlation between rSO₂ and StO₂ was weak (r = 0.254). rSO₂ readings by the Masimo O3™ device and pediatric sensor had good absolute and trending accuracies with respect to the calculated reference values in children undergoing cardiac surgery. rSO₂ and StO₂ cannot be used interchangeably.Clinical trial registration http://clinicaltrials.gov (number: NCT04208906).

Soft shape-programmable surfaces by fast electromagnetic actuation of liquid metal networks

Low modulus materials that can shape-morph into different three-dimensional (3D) configurations in response to external stimuli have wide-ranging applications in flexible/stretchable electronics, surgical instruments, soft machines and soft robotics. This paper reports a shape-programmable system that exploits liquid metal microfluidic networks embedded in an elastomer matrix, with electromagnetic forms of actuation, to achieve a unique set of properties. Specifically, this materials structure is capable of fast, continuous morphing into a diverse set of continuous, complex 3D surfaces starting from a two-dimensional (2D) planar configuration, with fully reversible operation. Computational, multi-physics modeling methods and advanced 3D imaging techniques enable rapid, real-time transformations between target shapes. The liquid-solid phase transition of the liquid metal allows for shape fixation and reprogramming on demand. An unusual vibration insensitive, dynamic 3D display screen serves as an application example of this type of morphable surface.

Low modulus materials that can change shape in response to external stimuli are promising for a wide range of applications. The authors here introduce a shape-reprogrammable construct, based on liquid metal microfluidic networks and electromagnetic actuation, that supports a unique collection of capabilities.

Critical incidents associated with pediatric anesthesia: changes over 6 years at a tertiary children’s hospital

Background: Sustained interest is needed in the characteristics of critical incidents in pediatric anesthesia and related changes, for determining the causes and degree of potential harm; this will also improve the quality of medical care. This study aimed to analyze the incidence of critical incidents recorded in 2014–2019, and to compare them with those in 2008–2013.Methods: Critical incidents associated with pediatric anesthesia, including cardiac arrest, recorded in a voluntary departmental reporting system between January 2014 and December 2019 were compared with those reported between January 2008 and August 2013 using chi-square test. Results: We identified 295 (0.55%) critical incidents from 53,541 cases of pediatric anesthesia (3,471 cardiothoracic surgeries); this is consistent with the previously reported incidence of 0.46%. Among the critical incidents, the incidences of adverse events, sentinel event, near miss case and no-harm events were 93.9%, 1.7%, 0%, and 6.1% in 2014–2019, whereas those were 98.3%, 2.6%, 1.7%, and 0% in 2008–2013 (P = 0.023, 0.686, 0.08, and < 0.001, respectively). Cardiac arrest accounted for 25 (8.5%) cases of the 295 critical events, which significantly lower than that previously reported (18.3%; P = 0.02). Human factor-related events accounted for 61.0% of all critical incidences; this was similar to the previous data (58.5%). Conclusions: Over six years, there has been no significant difference in the total incidence of critical events. Despite the decrease in the incidence of serious critical events, perioperative care in pediatric anesthesia can be further improved.

Soft skin-interfaced mechano-acoustic sensors for real-time monitoring and patient feedback on respiratory and swallowing biomechanics

Swallowing is a complex neuromuscular activity regulated by the autonomic nervous system. Millions of adults suffer from dysphagia (impaired or difficulty swallowing), including patients with neurological disorders, head and neck cancer, gastrointestinal diseases, and respiratory disorders. Therapeutic treatments for dysphagia include interventions by speech-language pathologists designed to improve the physiology of the swallowing mechanism by training patients to initiate swallows with sufficient frequency and during the expiratory phase of the breathing cycle. These therapeutic treatments require bulky, expensive equipment to synchronously record swallows and respirations, confined to use in clinical settings. This paper introduces a wireless, wearable technology that enables continuous, mechanoacoustic tracking of respiratory activities and swallows through movements and vibratory processes monitored at the skin surface. Validation studies in healthy adults (n = 67) and patients with dysphagia (n = 4) establish measurement equivalency to existing clinical standard equipment. Additional studies using a differential mode of operation reveal similar performance even during routine daily activities and vigorous exercise. A graphical user interface with real-time data analytics and a separate, optional wireless module support both visual and haptic forms of feedback to facilitate the treatment of patients with dysphagia.

A dynamically reprogrammable surface with self-evolving shape morphing

Dynamic shape-morphing soft materials systems are ubiquitous in living organisms; they are also of rapidly increasing relevance to emerging technologies in soft machines^1-3, flexible electronics^4,5 and smart medicines⁶. Soft matter equipped with responsive components can switch between designed shapes or structures, but cannot support the types of dynamic morphing capabilities needed to reproduce natural, continuous processes of interest for many applications^7-24. Challenges lie in the development of schemes to reprogram target shapes after fabrication, especially when complexities associated with the operating physics and disturbances from the environment can stop the use of deterministic theoretical models to guide inverse design and control strategies^25-30. Here we present a mechanical metasurface constructed from a matrix of filamentary metal traces, driven by reprogrammable, distributed Lorentz forces that follow from the passage of electrical currents in the presence of a static magnetic field. The resulting system demonstrates complex, dynamic morphing capabilities with response times within 0.1 second. Implementing an in situ stereo-imaging feedback strategy with a digitally controlled actuation scheme guided by an optimization algorithm yields surfaces that can follow a self-evolving inverse design to morph into a wide range of three-dimensional target shapes with high precision, including an ability to morph against extrinsic or intrinsic perturbations. These concepts support a data-driven approach to the design of dynamic soft matter, with many unique characteristics.

Ultrasound-guided esophageal compression during mask ventilation in small children: a prospective observational study

Background

The use of cricoid compression to prevent insufflation remains controversial, and its use in children is limited. This study aimed to examine the effect of real-time ultrasound-guided esophageal compression on the prevention of gastric insufflation.

Method

This prospective observational study was conducted with fifty children aged < 2 years undergoing general anesthesia. Patients were excluded if they were at an increased risk for gastric regurgitation or pulmonary aspiration. Following anesthetic induction under spontaneous breathing, ultrasound-guided esophageal compression was performed during pressure-controlled face-mask ventilation using a gradual increase in peak inspiratory pressure from 10 to 24 cm H₂O to determine the pressure at which gastric insufflation occurred. The primary outcome was the incidence of gastric insufflation during anesthetic induction with variable peak inspiratory pressure after real-time ultrasound-guided esophageal compression was applied.

Results

Data from a total of 42 patients were analyzed. Gastric insufflation was observed in 2 (4.7%) patients. All patients except one had their esophagus on the left side of the trachea. Applying ultrasound-guided esophageal compression did not affect the percentage of glottic opening scores (P = 0.220).

Conclusions

The use of real-time ultrasound-guided esophageal compression pressure can aid preventing gastric insufflation during face-mask ventilation in children less than 2 years old.

Trial registration

Clinicaltrials.gov identifier: NCT04645043.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01803-5.

Usefulness of bispectral index and patient state index during sevoflurane anesthesia in children: A prospective observational study

Cortical electroencephalography-based devices are used to monitor the depth of anesthesia. In this study, we evaluated the values of bispectral index (BIS) and patient state index (PSI) during sevoflurane anesthesia in children. The ability/accuracy of BIS and PSI to predict the maintenance and recovery state of anesthesia was evaluated based on prediction probability (Pk) values and the secondary outcomes were agreement and correlation of 2 monitors. Fifty children (3-12 years old) were enrolled and the patients received sevoflurane anesthesia with remifentanil followed by propofol administration. Before the induction of anesthesia, BIS and PSI sensors were simultaneously placed on the forehead, and data were collected until the end of anesthesia. Maintenance state was defined as the period following intubation until the cessation of sevoflurane, while recovery state was defined as the period following the cessation of sevoflurane until awake. Pk, agreement or correlation of BIS and PSI in different anesthesia state were calculated. Anesthesia reduced mean BIS and PSI values. Pk of BIS (95% confidential interval [CI]: 0.78-0.91) and PSI (95% CI: 0.82-0.91) for anesthesia were 0.85 and 0.87, respectively. Agreement was 0.79 for recovery state and 0.73 for maintenance state. Pk values were comparable for BIS and PSI. Agreement between BIS and PSI measurements in the same state was relatively good. Therefore, these monitors are appropriate for monitoring for different state of anesthesia in pediatric population.

Use of high-flow nasal oxygen in spontaneously breathing pediatric patients undergoing tubeless airway surgery: A prospective observational study

The use of high-flow nasal oxygen is gaining popularity in apneic and spontaneously breathing adult patients during anesthesia. This prospective observational study evaluated the effect of high-flow nasal oxygen in maintaining adequate oxygenation and ventilation in spontaneously breathing pediatric patients with dynamic airway obstruction, undergoing tubeless airway surgery. Oxygenation was provided via an age-appropriate, high-flow nasal cannula at a flow rate of 2 L kg-1 min-1. Propofol and remifentanil were used to maintain anesthesia while preserving spontaneous respiration. We sought to determine the incidence and risk factors of rescue ventilation. Rescue ventilation with a face mask was performed when the pulse oximetry oxygen saturation was <90% or transcutaneous carbon dioxide was >80 mm Hg. In total, 27 patients were included in the final analysis. Median (interquartile range) of pulse oximetry and transcutaneous carbon dioxide were 100% (99%-100%) and 58.4 mm Hg (51.4-70.3 mm Hg), respectively. Altogether, 9 (33.3%) patients needed rescue ventilation during anesthesia. Of these, 7 patients (25.9%) developed oxygen desaturation (<90%) and 2 patients (7.4%) developed hypercarbia. Patients who required rescue ventilation were significantly younger (8.2 vs 28.8 months, P = .02) and required a longer anesthesia time (55.7 vs 41.0 minutes, P = .04) than those who did not. In conclusion, High-flow nasal oxygen is an alternative technique to maintain oxygenation in children undergoing airway surgeries. However, younger age and longer anesthesia time are significant risk factors leading to the requirement of rescue ventilation in these patients. Further studies with large sample size are required for clinical application of these techniques.

Performance time of anesthesiology trainees for cricothyroid membrane identification and characteristics of cricothyroid membrane in pediatric patients using ultrasonography

BACKGROUND

Identifying the cricothyroid membrane is an essential technical skill for front-of-neck access procedures.

AIMS

This study evaluated the usefulness of cricothyroid membrane identification in pediatric patients using ultrasonography by anesthesiology trainees without experience in airway ultrasound and collected anatomical data on the cricothyroid membrane and its surrounding airway structures in children.

METHODS

This prospective observational study included children aged <18 years scheduled to undergo general anesthesia and anesthesiology trainees who identified the cricothyroid membrane in five sequential anesthetized patients using ultrasonography. A pediatric anesthesiologist confirmed the accuracy of the identified cricothyroid membrane and recorded the performance time. The primary aims were the cricothyroid membrane identification success rate and performance time. The secondary aims were the characterization of the cricothyroid membrane and its surrounding structures.

RESULTS

Overall, 150 pediatric patients and 30 anesthesiology trainees were analyzed. The cricothyroid membrane identification success rate using ultrasonography was 100% in all the attempts using a transverse approach. The mean (standard deviation) performance time was 27.2 (18.6) s and 31.0 (23.8) s using the transverse and longitudinal approaches, respectively. The performance time decreased by 3.1 (p = .003, 95% confidence interval [CI] = -5.1--1.0) and 5.2 (p = .007, 95% CI = -8.9--1.4) seconds per increase in number of attempts with the transverse and longitudinal approaches, respectively. The cricothyroid membrane length was mostly correlated with the patients' height (r = .75, p < .001), and the blood vessels surrounding the cricothyroid membrane were observed in 95.9% of the patients.

CONCLUSIONS

Anesthesiology trainees without experience in airway ultrasound successfully identified the cricothyroid membrane in pediatric patients using ultrasonography after a brief training period. Further research is required as the identification of a structure does not predict the success of the actual procedure, particularly if done in an emergency situation.

Effect of remifentanil on post-operative analgesic consumption in patients undergoing shoulder arthroplasty after interscalene brachial plexus block: a randomized controlled trial

PURPOSE

Remifentanil is useful in balanced anesthesia; however, there is concern regarding opioid-induced hyperalgesia. The effect of remifentanil on rebound pain, characterized by hyperalgesia after peripheral nerve block has rarely been studied. This study evaluated whether intraoperative remifentanil infusion may increase postoperative analgesic requirement in patients receiving preoperative interscalene brachial plexus block (IBP).

METHODS

Sixty-eight patients undergoing arthroscopic shoulder surgery under general anesthesia were randomly allocated to remifentanil (R) or control (C) group. Preoperative IBP with 0.5% ropivacaine 15 mL was performed in all patients. Intraoperative remifentanil was administered only in the R group. Postoperative pain was controlled using intravenous patient-controlled analgesia (IV-PCA) and rescue analgesics. The primary outcome was the dosage of fentanyl-nefopam IV-PCA infused over 24 h postoperatively. The secondary outcomes included the numeric rating scale (NRS) score recorded at 4-h intervals over 24 h, amount of rescue analgesics and total postoperative analgesics used over 24 h, occurrence of intraoperative hypotension, postoperative nausea and vomiting (PONV) and delirium.

RESULTS

The dosage of fentanyl-nefopam IV-PCA was significantly less in C group than R group for postoperative 24 h. Fentanyl 101 [63-158] (median [interquartile range]) µg was used in the C group, while fentanyl 161 [103-285] µg was used in the R group (median difference 64 µg, 95% CI 10-121 µg, P = 0.02). Nefopam 8.1 [5.0-12.6] mg was used in the C group, while nefopam 12.9 [8.2-22.8] mg was used in the R group (median difference 5.1 mg, 95% CI 0.8-9.7 mg, P = 0.02). The total analgesic consumption: the sum of PCA consumption and administered rescue analgesic dose, converted to morphine milligram equivalents, was higher in the R group than C group (median difference 10.9 mg, 95% CI 3.0-19.0 mg, P = 0.01). The average NRS score, the incidence of PONV and delirium, were similar in both groups. The incidence of intraoperative hypotension was higher in R group than C group (47.1% vs. 20.6%, P = 0.005).

CONCLUSIONS

Remifentanil administration during arthroscopic shoulder surgery in patients undergoing preoperative IBP increased postoperative analgesic consumption.

Effect of end-tidal carbon dioxide level on the optic nerve sheath diameter measured by transorbital ultrasonography in anesthetized pediatric patients: A randomized trial

BACKGROUND

Intraoperative hypercapnia and hypocapnia are common during pediatric anesthesia, and the cerebral blood flow and intracranial pressure may be affected by the partial pressure of arterial carbon dioxide. Transorbital ultrasound measurement of the optic nerve sheath diameter is a simple and non-invasive method for intracranial pressure assessment. The objective of this study was to evaluate the effect of end-tidal carbon dioxide (E_T CO₂ ) on optic nerve sheath diameter in a healthy anesthetized pediatric population.

METHODS

Pediatric patients scheduled for elective surgery under general anesthesia and mechanical ventilation in the supine position were enrolled and divided into four subgroups; age <2 years, 2-6 years, 6-12 years, and 12-18 years. Mechanical ventilation was adjusted to achieve target E_T CO₂ levels in a randomized sequence (40-35-45-40 mmHg or 40-45-35-40 mmHg). Three minutes after reaching each target E_T CO₂ level, transorbital ultrasound images of optic nerve sheath diameter were obtained and analyzed. The primary outcome was the optic nerve sheath diameter at each E_T CO₂ level.

RESULTS

Sixty-four pediatric patients were enrolled and analyzed. At E_T CO₂  = 40 mmHg, the optic nerve sheath diameter was 5.6 ± 0.6 mm, 6.4 ± 0.5 mm, 6.8 ± 0.6 mm, and 7.1 ± 0.5 mm in children aged <2 years, 2-6 years, 6-12 years, and 12-18 years, respectively. The overall percent decreases in the optic nerve sheath diameter was -5.6 ± -4.3% (95% CI; -6.7 to -4.5%) at E_T CO₂  = 35 mmHg while the overall percent increases of optic nerve sheath diameter (ONSD) was 4.9 ± 5.1% (95% CI; 3.6 to 6.1%) at E_T CO₂  = 45 mmHg compared with those at E_T CO₂  = 40 mmHg. Spearman rank correlation analysis indicated that there were weak to moderate correlation between E_T CO₂ and the optic nerve sheath diameter (correlation coefficient [p-value] = .355 [.004], .318 [.014], .373 [<.001], and .420 [<.001] in children aged <2 years, 2-6 years, 6-12 years, and 12-18 years, respectively).

CONCLUSIONS

The optic nerve sheath diameter measured by transorbital ultrasound showed rapid reactivity from E_T CO₂ 35 to 45 mmHg in healthy pediatric patients under inhalation general anesthesia.

Resonant Ionic, Covalent Bond, and Steric Characteristics Present in 1Σu+ States of Li2

The molecular bonding in the excited states of the alkali dimers involves the resonant ionic, covalent bond and steric interactions. We show here the case of the ¹Σ_u⁺ states of Li₂ by ab initio calculation. These interactions as functions of the internuclear distance lead to complex potential energy curves, providing an important application for high resolution laser spectroscopy. The spectroscopic constants for the 4 and 5 ¹Σ_u⁺ states are obtained for the first time.

Prediction of fluid responsiveness following liver compression in pediatric patients with single ventricle physiology

INTRODUCTION

The role of liver compression in predicting fluid responsiveness in children with a single ventricle has never been evaluated. The purpose of this study was to assess whether blood pressure changes during liver compression predict fluid responsiveness in children with single ventricle physiology.

METHODS

This prospective, interventional study included children aged 3 months to 5 years who underwent surgery for bidirectional cavopulmonary shunt or extracardiac Fontan operation. Before fluid loading, the right upper abdomen was compressed at 30 mmHg for 10 s, and changes in the blood pressure waves were recorded before administering 10 ml kg^-1 of crystalloid solution. Systolic arterial pressure, diastolic arterial pressure, central venous pressure, pleth variability index, respiratory variation in aortic blood flow peak velocity, and stroke volume were measured before and after fluid loading. A volume responder was defined as a patient with >15% increase in stroke volume index.

RESULTS

Thirty patients underwent bidirectional cavopulmonary shunt (15 responders and 15 non-responders), and 32 underwent Fontan surgery (17 responders and 15 non-responders). In children with bidirectional cavopulmonary shunt, Δsystolic arterial pressure > 8 mmHg (sensitivity 76.9% and specificity 93.3%), Δdiastolic arterial pressure > 7 mmHg (sensitivity 69.2% and specificity 93.3%), and Δmean arterial pressure > 7 mmHg (sensitivity 69.2% and specificity 100%) during liver compression predicted fluid responsiveness. The areas under the receiver operating characteristic curves of Δsystolic arterial pressure, Δdiastolic arterial pressure, and Δmean arterial pressure were 0.928, 0.859, and 0.874 (all p < .001). In children who underwent Fontan surgery, only Δsystolic arterial pressure > 16 mmHg was predictive of fluid responsiveness (sensitivity of 41.2% and specificity of 100%), with the areas under the receiver operating characteristic curves curve of 0.786 (p < .001). Pleth variability index and respiratory variation in aortic blood flow peak velocity had no predictive value for fluid responsiveness after both types of surgeries.

DISCUSSION

In BCPS patients, liver compression increases the inferior vena cava flow which directly leads to an increase in preload. On the other hand, blood flow from the liver drains directly into the pulmonary arteries in Fontan circulation. Because of this characteristics for preload determination, the clinical application of liver compression to monitor hemodynamic changes might be more useful in patients with bidirectional cavopulmonary shunt than those with Fontan circulation.

CONCLUSION

Increase in blood pressure induced by liver compression is predictive of fluid responsiveness in children with single ventricle physiology.