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.

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.

Atmospheric particulate matter and hypoxaemia in Korean children receiving general anaesthesia: A retrospective analysis.

BACKGROUND: The association between the concentration of atmospheric particulate matter on the day of surgery and the occurrence of intra-operative hypoxaemia in children receiving general anaesthesia is unclear. OBJECTIVE: To investigate the association between the exposure to of particulate matter on the day of surgery and the occurrence of intra-operative hypoxaemia, defined as a pulse oximetry oxygen saturation of less than 90% for more than 1 min, in children. DESIGN: Retrospective study. SETTING: Single-centre. PARTICIPANTS: Children aged 18 years or younger who received general anaesthesia between January 2019 and October 2020. INTERVENTION: Information on daily levels of particulate matter with a diameter 10 µm or less and 2.5 µm or less measured within a neighbourhood corresponding to the area defined by the hospital's zip code was obtained from publicly available air-quality data. MAIN OUTCOME MEASURES: The primary outcome was intra-operative hypoxaemia, defined as a pulse oximetry oxygen saturation of less than 90% lasting for more than 1 min, manually verified by anaesthesiologists using vital sign registry data extracted at 2 s intervals. RESULTS: Of the patients finally analysed, 3.85% (489/13 175) experienced intra-operative hypoxaemia. Higher levels of particulate matter 10 µm or less in diameter (≥81 µg m-3, 472/12 900, 3.7%) were associated with an increased occurrence of intra-operative hypoxaemia compared with lower particulate matter concentrations [<81 µg m-3, 17/275, 6.2%; adjusted odds ratio, 1.71; 95% confidence interval (CI), 1.04 to 2.83; P = 0.035]. CONCLUSION: The level of particulate matter on the day of surgery pose a risk of intra-operative hypoxaemia in children receiving general anaesthesia. If the concentrations of particulate matter 10 µm or less in diameter on the day of surgery are high, children receiving general anaesthesia should be managed with increased caution.

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) ( https://classic.clinicaltrials.gov/ct2/show/NCT05030649 ).

Effects of goal-directed analgesia using the analgesia nociception index in children undergoing surgery for moyamoya disease: A randomised controlled trial.

BACKGROUND: The potential benefits of Analgesia Nociception Index guided intra-operative analgesia on intra-operative opioid consumption remains to be demonstrated in paediatric anaesthesia. OBJECTIVES: This study aimed to explore the effects of Analgesia Nociception Index guided analgesia on sufentanil consumption during anaesthesia and postoperative pain scores in paediatric patients with moyamoya disease. DESIGN: A prospective randomised controlled study. SETTING: Seoul National University Children's Hospital, Seoul, Republic of Korea. PATIENTS: A total of 40 children scheduled for encephaloduroarteriosynangiosis. MAIN OUTCOME MEASURES: The primary outcome was total intra-operative sufentanil consumption, and the secondary outcomes included postoperative pain scores and incidence of opioid-related adverse events. RESULTS: The Analgesia Nociception Index group showed lower intra-operative sufentanil consumption (in µg kg-1 h-1) compared with the Standard group (0.30 ±â€Š0.12 and 0.39 ±â€Š0.17, respectively; mean difference, -0.09; 95% confidence interval, -0.19 to 0.00; P = 0.049). Postoperatively, compared with the Standard group, the Analgesia Nociception Index group reported lower median pain scores at 18 and 24 h and maximum pain within 24 h (1 [0 to 2] vs. 3 [2 to 5]; P = 0.004, 1 [0 to 2] vs. 3 [1 to 4]; P = 0.041, and 4 [3 to 5] vs. 5 [4 to 7]; P = 0.045, respectively), with fewer patients experiencing nausea (3 [15%] vs. 10 [50%], P = 0.043). CONCLUSION: The Analgesia Nociception Index guided analgesic protocol can reduce intra-operative sufentanil consumption and postoperative pain within 24 h with fewer nausea symptoms in paediatric patients with moyamoya disease who undergo encephaloduroarteriosynangiosis. TRIAL REGISTRATION NUMBER: NCT05672212 (registered at clinicaltrials, principal investigator: K.E.H., registration date: 2 January 2023).

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.

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 ß-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.

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.

RéSUMé: OBJECTIF: L'augmentation de la pulsatilité du flux de la veine porte est associée à des complications majeures après une chirurgie cardiaque chez l'adulte. Néanmoins, aucune donnée n'est disponible pour la patientèle pédiatrique atteinte de cardiopathie congénitale. Nous avons émis l'hypothèse que les paramètres Doppler, y compris la pulsatilité du flux de la veine porte, pourraient être associés aux devenirs postopératoires des enfants bénéficiant de diverses chirurgies cardiaques. MéTHODE: Nous avons réalisé une étude de cohorte observationnelle prospective portant sur des enfants bénéficiant d'une chirurgie cardiaque congénitale. Nous avons obtenu des données Doppler des veines porte, spléniques et hépatiques postopératoires ainsi que des données cliniques périopératoires, y compris les complications postopératoires majeures. La pulsatilité du flux des veines porte et spléniques a été calculée. Nous avons évalué l'association entre les paramètres Doppler veineux et les issues indésirables. L'objectif principal était de déterminer si la pulsatilité du flux postopératoire de la veine porte pouvait constituer un indicateur des complications majeures après une chirurgie cardiaque congénitale. RéSULTATS: Dans cette étude, nous avons recruté 389 enfants, dont 74 ont présenté des complications postopératoires majeures. La pulsatilité moyenne de la veine porte (écart type) (44 [30] % vs 25 [14] %; intervalle de confiance [IC] à 95 % pour la différence moyenne, 12 à 26; P < 0,001] et les indices de pulsatilité splénique (41 [30] % vs 26 [16] %; IC 95 %, 7 à 23; P < 0,001) étaient significativement plus élevés chez les enfants présentant des complications postopératoires que chez les enfants sans complications. L'indice de pulsatilité de la veine porte a permis d'identifier les complications postopératoires chez les patient·es biventriculaires et les patient·es univentriculaires recevant une anastomose cavo-pulmonaire bidirectionnelle (procédure de Glenn), alors que ce n'était pas le cas chez les autres patient·es univentriculaires. Une augmentation postopératoire de l'indice de pulsatilité de la veine porte était significativement associée à des complications majeures après une chirurgie cardiaque pédiatrique (rapport de cotes, 1,40; IC 95 %, 1,29 à 1,91; P < 0,001). CONCLUSION: Une pulsatilité plus élevée de la veine porte est associée à des complications postopératoires majeures chez les enfants bénéficiant d'une chirurgie cardiaque. Néanmoins, davantage de données sont nécessaires pour conclure à l'efficacité de la pulsatilité de la veine porte chez les patient·es présentant une physiologie univentriculaire. ENREGISTREMENT DE L'éTUDE: ClinicalTrials.gov (NCT03990779); enregistrée le 19 juin 2019.

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. (ß = -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.

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.

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 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.

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.

Determining optimal positive end-expiratory pressure and tidal volume in children by intratidal compliance: a prospective observational study.

BACKGROUND: Limited data exist regarding optimal intraoperative ventilation strategies for the paediatric population. This study aimed to determine the optimal combination of PEEP and tidal volume (VT) based on intratidal compliance profiles in healthy young children undergoing general anaesthesia. METHODS: During anaesthesia, infants (1 month-1 yr), toddlers (1-3 yr), and children (3-6 yr) were assigned serially to four ventilator settings: PEEP 8 cm H2O/VT 8 ml kg-1 (PEEP8/VT8), PEEP 10 cm H2O/VT 5 ml kg-1 (PEEP10/VT5), PEEP 10 cm H2O/VT 8 ml kg-1 (PEEP10/VT8), and PEEP 12 cm H2O/VT 5 ml kg-1 (PEEP12/VT5). The primary outcome was intratidal compliance profile, classified at each ventilator setting as horizontal (indicative of optimal alveolar ventilatory conditions), increasing, decreasing, or combinations of increasing/decreasing/horizontal compliance. Secondary outcomes were peak inspiratory, plateau, and driving pressures. RESULTS: Intratidal compliance was measured in 15 infants, 13 toddlers, and 15 children (15/43 [35%] females). A horizontal compliance profile was most frequently observed with PEEP10/VT5 (60.5%), compared with PEEP10/VT8, PEEP8/VT8, and PEEP12/VT5 (23.3-34.9%; P<0.001). Decreasing compliance profiles were most frequent when VT increased to 8 ml kg-1, PEEP increased to 12 cm H2O, or both. Plateau airway pressures were lower at PEEP8/VT8 (16.9 cm H2O [2.2]) and PEEP10/VT5 (16.7 cm H2O [1.7]), compared with PEEP10/VT8 (19.5 cm H2O [2.1]) and PEEP12/VT5 (19.0 cm H2O [2.0]; P<0.001). Driving pressure was lowest with PEEP10/VT5 (4.6 cm H2O), compared with other combinations (7.0 cm H2O [2.0]-9.5 cm H2O [2.1]; P<0.001). CONCLUSIONS: VT 5 ml kg-1 combined with 10 cm H2O PEEP may reduce atelectasis and overdistension, and minimise driving pressure in the majority of mechanically ventilated children <6 yr. The effect of these PEEP and VT settings on postoperative pulmonary complications in children undergoing surgery requires further study. CLINICAL TRIAL REGISTRATION: NCT04633720.

Pupil response to painful stimuli during inhalation anaesthesia without opioids in children.

BACKGROUND: Pupil dilation reflex measured by a pupillometer is known to be a useful parameter for assessing the response to perioperative noxious stimuli. In children, pupillometer can reflect changes after painful stimuli during anaesthesia or guide anaesthesia to reduce opioid consumption. However, to date, there are no data regarding pupil response during inhalation anaesthesia with analgesia by intravenous acetaminophen in children. METHODS: We planned a prospective, single-armed study of children aged between 3 and 12 years who underwent surgery under general anaesthesia. Anaesthesia was maintained by 1 minimum alveolar concentration (MAC) of sevoflurane, and 15 mg/kg of acetaminophen was administered. Patients' left eye was examined using a pupillometer after induction, before and after skin incision and train-of-four stimulus. Pupil diameter and other pupillometric parameters were recorded. Increase in heart rate by 15% was regarded as insufficient analgesia to skin incision and indicative powers of pupillometric parameters for insufficient analgesia were examined by receiver-operating characteristics. RESULTS: A total of 33 patients were included. Enlarged pupil, large increase in pupil diameter and low neurological pupil index (NPi) after skin incision were good indicators of insufficient analgesia for skin incision. Children with insufficient analgesia showed abnormal NPi value. However, increase in pupil diameter and decrease in NPi were observed even in patients without increase in the heart rate after the skin incision. CONCLUSIONS: We suggest dilation of the pupil and decrease in NPi can indicate response to noxious stimuli in children. Regardless of sufficiency of analgesia, pupil dilation and decrease in NPi were observed after skin incision in children under general anaesthesia with 1 MAC of sevoflurane and intravenous acetaminophen.

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.

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 (ET 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 ET CO2 levels in a randomized sequence (40-35-45-40 mmHg or 40-45-35-40 mmHg). Three minutes after reaching each target ET 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 ET CO2 level. RESULTS: Sixty-four pediatric patients were enrolled and analyzed. At ET 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 ET 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 ET CO2  = 45 mmHg compared with those at ET CO2  = 40 mmHg. Spearman rank correlation analysis indicated that there were weak to moderate correlation between ET 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 ET CO2 35 to 45 mmHg in healthy pediatric patients under inhalation general anesthesia.

Central venous catheter-related thrombosis in pediatric surgical patients: A prospective observational study.

BACKGROUND: Perioperative central venous catheters are required but may be associated with various complications. AIMS: The purpose of our study was to assess the incidence and perioperative risk factors for catheter-related internal jugular vein thrombosis in pediatric surgical patients. METHODS: This prospective observational study included children under 6 years of age who were scheduled to undergo central venous catheterization of the right internal jugular vein under general anesthesia. A central venous catheter was inserted under real-time ultrasound guidance. An investigator examined for thrombosis using ultrasonography at predetermined time points. The primary aim was the incidence of catheter-related thrombosis from insertion until the 5th day postoperatively or the removal of the central venous catheter. The secondary aim was the determination of the risk factors for thrombosis. RESULTS: Eighty patients completed the study. Internal jugular vein thrombi were found in 31 patients (38.8%, 95% CI 28.0-49.4). On multiple logistic regression analyses, the number of insertion attempts was the only influencing factor for catheter-related thrombosis (p < .001). More than two insertion attempts increased the risk of thrombosis (odds ratio 5.6; 95% CI 1.7 - 18.7, p = .004). Anesthesia time (p = .017; mean difference 166.4 min; 95% CI 55.7-277.1), intraoperative red blood cell transfusion (p = .001; median difference 21.1 ml kg-1 ; 95% CI 6.6-34.4), and intensive care unit stay (p = .001; median difference 100.0 h; 95% CI 48-311) differed between patients with transient thrombosis and those with thrombosis lasting for more than 3 days. CONCLUSION: Internal jugular vein thrombosis was frequently detected by ultrasound following central venous catheterization in pediatric surgical patients. Multiple insertion attempts may be associated with the incidence of thrombosis. The clinical relevance of thrombi detected via ultrasound surveillance has not been determined.

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.

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.