Effect of different fraction of inspired oxygen on development of atelectasis in mechanically ventilated children: A randomized controlled trial

Pulmonary Atelectasis After Sedation With Propofol vs Propofol-Ketamine for Magnetic Resonance Imaging in Children: A Randomized Clinical Trial

Importance

Little is known about the impact of different anesthetic agents used for routine magnetic resonance imaging (MRI) sedation on pulmonary function in children.

Objective

To compare the incidence of pulmonary atelectasis after MRI sedation with propofol vs propofol-ketamine.

Design, Setting, and Participants

This double-masked randomized clinical trial screened 117 consecutive pediatric patients aged 3 to 12 years with American Society of Anesthesiologists physical status I to II undergoing elective MRI under deep sedation from November 2, 2022, to April 28, 2023, at a tertiary referral center. Four patients met the exclusion criteria, and 5 patients refused to participate. The participants and outcome assessors were masked to the group allocation.

Interventions

During the MRI, the propofol group received 0.2 mL/kg of 1% propofol and 2 mL of 0.9% saline followed by a continuous infusion of propofol (200 μg/kg/min) and 0.9% saline (0.04 mL/kg/min). The propofol-ketamine group received 0.2 mL/kg of 0.5% propofol and 1 mg/kg of ketamine followed by a continuous infusion of propofol (100 μg/kg/min) and ketamine (20 μg/kg/min).

Main Outcome and Measure

The incidence of atelectasis assessed by lung ultrasonography examination.

Results

A total of 107 children (median [IQR] age, 5 [4-6] years; 62 male [57.9%]), with 54 in the propofol group and 53 in the propofol-ketamine group, were analyzed in this study. Notably, 48 (88.9%) and 31 (58.5%) patients had atelectasis in the propofol and propofol-ketamine groups, respectively (relative risk, 0.7; 95% CI, 0.5-0.8; P < .001). The incidence of desaturation and interruption of the MRI due to airway intervention or spontaneous movement did not significantly differ between the groups. The propofol-ketamine group showed a faster emergence time than the propofol group (15 [9-23] vs 25 [22-27] minutes in the propofol-ketamine vs propofol group; median difference in time, 9.0 minutes; 95% CI, 6.0-12.0 minutes; P < .001). No patient was withdrawn from the trial due to adverse effects.

Conclusions and Relevance

In this randomized clinical trial, the propofol-ketamine combination reduced sedation-induced atelectasis while allowing for faster emergence compared with propofol alone.

Trial Registration

cris.nih.go.kr Identifier: KCT0007699.

Lung ultrasound assessment of atelectasis following different anesthesia induction techniques in pediatric patients: a propensity score-matched, observational study

INTRODUCTION

Atelectasis is a well-documented complication in pediatric patients undergoing general anesthesia. Its incidence varies significantly based on surgical procedures and anesthesia techniques. Inhalation induction, commonly used to avoid the discomfort of venipuncture, is suspected to cause higher rates of respiratory complications, including atelectasis, compared to intravenous induction. This study aimed to evaluate the impact of inhalation versus intravenous anesthesia induction on atelectasis formation in pediatric patients, as assessed by lung ultrasound (LUS).

METHODS

This propensity score-matched observational study was conducted at a tertiary pediatric hospital in Milan, Italy. Inclusion criteria were children ≤ 18 years undergoing elective surgery with general anesthesia. Patients were divided into inhalation and intravenous induction groups. LUS was performed before and after anesthesia induction to assess lung aeration. The primary endpoint was the global LUS score post-induction, with secondary endpoints including the incidence and distribution of atelectasis.

RESULTS

Of the 326 patients included, 65% underwent inhalation induction and 35% intravenous induction. The global LUS score was significantly higher in the inhalation group (12.0 vs. 4.0, p < 0.001). After propensity score matching (for age, presence of upper respiratory tract infection, duration of induction, and PEEP levels at induction), average treatment effect (ATE) of mask induction was 5.89 (95% CI, 3.21-8.58; p < 0.001) point on LUS global score and a coefficient of 0.35 (OR 1.41) for atelectasis.

DISCUSSION

Inhalation induction is associated with a higher incidence of atelectasis in pediatric patients also when we adjusted for clinically relevant covariates.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT06069414.

Lung ultrasound score-based assessment of postoperative atelectasis in obese patients according to inspired oxygen concentration: A prospective, randomized-controlled study

BACKGROUND

According to a recent meta-analysis, in patients with a body mass index (BMI) ≥ 30, a high fraction of inhaled oxygen (FiO2) did not increase postoperative atelectasis. However, a high FiO2 generally increases the risk of postoperative atelectasis. Therefore, this study aimed to evaluate the effect of FiO2 on the development of atelectasis in obese patients using the modified lung ultrasound score (LUSS).

METHODS

Patients were assigned to 4 groups: BMI ≥ 30: group A (n = 21) and group B (n = 20) and normal BMI: group C (n = 22) and group D (n = 21). Groups A and C were administered 100% O2 during preinduction and emergence and 50% O2 during anesthesia. Groups B and D received 40% O2 for anesthesia. The modified LUSS was assessed before and 20 min after arrival to the postanesthesia care unit (PACU).

RESULTS

The difference between the modified LUSS preinduction and PACU was significantly higher in group A with a BMI ≥ 30 (P = .006); however, there was an insignificant difference between groups C and D in the normal BMI group (P = .076).

CONCLUSION

High FiO2 had a greater effect on the development of atelectasis in obese patients than did low FiO2; however, in normal-weight individuals, FiO2 did not have a significant effect on postoperative atelectasis.

Atelectasis and lung recruitment in pediatric anesthesia: An educational review

General anesthesia is associated with development of pulmonary atelectasis. Children are more vulnerable to the development and adverse effects of atelectasis. We review the physiology and risk factors for the development of atelectasis in pediatric patients under general anesthesia. We discuss the clinical significance of atelectasis, the use and value of recruitment maneuvers, and other techniques available to minimize lung collapse. This review demonstrates the value of a recruitment maneuver, maintaining positive end-expiratory pressure (PEEP) until extubation and lowering FiO₂ where possible in the daily practice of the pediatric anesthetist.

Association of regional cerebral oxygen saturation and postoperative pulmonary complications in pediatric patients undergoing one-lung ventilation: A propensity score matched analysis of a prospective cohort study

BACKGROUND

Previous studies of the relationship of regional cerebral oxygen saturation (rScO2) and postoperative pulmonary complications (PPCs) in pediatric patients are not well established, and further investigation is warranted. The aim of this prospective study was to determine whether a decrease in intraoperative rScO2 is associated with PPCs in children undergoing thoracoscopic surgery requiring one-lung ventilation (OLV).

METHODS

One hundred and six children of ages 3 months to 8 years who received one-lung ventilation were enrolled in the study. Upon entering the operating room, regional cerebral oxygen saturation was continuously monitored bilaterally by near-infrared spectroscopy. Patients were divided into low rScO2 (L-rScO2) or high rScO2 (H- rScO2) groups according to whether the lowest intraoperative rScO2 value was 15% lower than the baseline value. Outcome is defined as PPCs occurring within 7 days after surgery.

RESULTS

After propensity score matching, 23 pediatric patients with decreased rScO2 and 46 pediatric patients without a decrease in rScO2 were included in this study. According to logistic regression analysis, patients in the H- rScO2 group were less likely to have PPCs than those in the L-rScO2 group (OR = 3.16; 95% CI = 1.05-9.5; P = 0.04). Moreover, intraoperative rScO2 reduction was associated with an increase in the severity of PPCs (OR = 3.90; 95% CI = 1.19-12.80; P = 0.025).

CONCLUSIONS

The decrease in regional cerebral oxygen saturation during surgery increases the likelihood of postoperative pulmonary complications.

Evaluation of atelectasis using electrical impedance tomography during procedural deep sedation for MRI in small children: A prospective observational trial

STUDY OBJECTIVE

To investigate the variation of poorly ventilated lung units (i.e., silent spaces) in children undergoing procedural sedation in a day-hospital setting, until discharge home from the Post-Anesthesia Care Unit (PACU).

DESIGN

Prospective, single-center, observational cohort trial.

SETTING

This study was conducted at the radiology department and in PACU at Bern University Hospital (Switzerland), a tertiary care hospital.

PATIENTS

We included 25 children (1-6 years, ASA I-III) scheduled for cerebral magnetic resonance imaging scan, spontaneously breathing under deep sedation. Children planned for tracheal intubation, supraglottic airway insertion, or with contraindication for propofol were excluded.

INTERVENTION

After intravenous or inhaled induction, deep sedation was performed with 10 mg/kg/h Propofol. All children received nasal oxygen 0.3 ml/kg/min.

MEASUREMENTS

The proportion of silent spaces and the global inhomogeneity index were determined at each of five procedural points, using electrical impedance tomography: before induction (T1); before (T2) and after (T3) magnetic resonance imaging; at the end of sedation before transport to the PACU (T4); and before hospital discharge (T5).

MAIN RESULTS

The median [interquartile range (IQR)] proportion of silent spaces at the five analysis points were: T1, 5% [2%-14%]; T2, 10% [7%-14%]; T3, 12% [5%-23%]; T4, 12% [7%-24%]; and T5, 3% [2%-11%]. These defined significant changes in silent spaces over the course of sedation (p = 0.009), but no differences in silent spaces from before induction to before discharge from the PACU (T1 vs. T5; p = 0.29). Median [IQR] global inhomogeneity indices were 0.57 [0.55-0.58], 0.56 [0.53-0.59], 0.56 [0.54-0.59], 0.57 [0.54-0.60] and 0.56 [0.54-0.57], respectively (p = 0.93). None of the children reported anesthesia-related complications.

CONCLUSION

Deep sedation results in significantly increased poorly ventilated lung units during sedation. However, this does not significantly affect ventilation homogeneity, which was fully resolved at discharge from the PACU.

TRIAL REGISTRATION

clinicaltrials.gov, identifier NCT04507581.

Effect of intra-operative high inspired fraction of oxygen on postoperative nausea and vomiting in children undergoing surgery: A prospective randomised double-blind study

BACKGROUND

Administration of high inspired fraction of oxygen (FiO2) during anaesthesia has been proposed to decrease postoperative nausea and vomiting (PONV) in adults but has not been extensively studied in children.

OBJECTIVES

The primary objective of this study was to evaluate the effect of 80% FiO2 on the incidence of PONV in children undergoing surgery.

DESIGN

Prospective, randomised, study.

SETTING

Single-centre, teaching hospital.

PATIENTS

Children of either gender in the age group of 5 to 15 years scheduled for elective surgeries were assessed for eligibility. In cases of emergency surgeries; patients receiving supplemental oxygen pre-operatively or on mechanical ventilation; sepsis; bowel obstruction or ischaemia; poor nutritional status; anaemia (Hb <8 g%) or surgeries lasting less than 1 h or greater than 4 h were excluded from the study.

INTERVENTIONS

After induction of anaesthesia, children were randomised to receive either 30 or 80% oxygen in air, till the end of surgery.

MAIN OUTCOME MEASURES

Incidence of PONV within 24 h; surgical site infections (SSI)s; serum serotonin and TNF-α levels and the incidence of postoperative pulmonary complications (PPC)s were studied.

RESULTS

The overall 24 h incidence of PONV was not different between the low and high FiO2 groups [24 vs. 23%; P = 0.84; odds ratio (OR) 0.92; 95% confidence interval (CI), 0.44 to 2.06]. The incidence of SSIs (15 vs. 12%; P = 0.61; OR 0.77; 95% CI, 0.28 to 2.10) and PPCs (12 vs. 8%; P = 0.38; OR 0.59; 95% CI, 0.18 to 1.92) were not significant between the low and high FiO2 groups, respectively. Intragroup and intergroup comparisons of serum serotonin and TNF-α showed no significant difference either at baseline or at the end of surgery.

CONCLUSION

High intra-operative FiO2 of 80% does not provide additional protection against PONV in children.

TRIAL REGISTRATION

The study was registered with Clinical Trials Registry of India (CTRI) with trial registration no: CTRI/2018/07/014974.

Development of a Chinese Version of the State Behavioral Scale for Mechanically Ventilated Children

PURPOSE

To develop a Chinese version of the State Behavioral Scale (SBS-C) and to evaluate its reliability and validity for sedation assessment in mechanically ventilated children in China.

DESIGN AND METHODS

Cross-sectional survey design was used in a two-part study of mechanically ventilated children, aged 6 weeks to 6 years. A total 172 children and 145 children were recruited from Jan-Dec 2017 and Jan-Dec 2018, respectively, at a tertiary care pediatric hospital in southeast China. Following translation of the scale, the content validity was established by the content validity index, internal consistency was established using Cronbach's α, and construct validity was confirmed by correlation with a similar well-recognized scale, the COMFORT Scale-Chinese version (CS-C).

RESULTS

The content validity index for the seven scale dimensions ranged from 0.83 to 1.0 and for the full scale was 0.932. In the first study, Cronbach's α for the full SBS-C was 0.986 and for the seven scale dimensions ranged from 0.973 to 0.983; similarly, in the second study, Cronbach's α for the full scale was 0.983 and for the seven dimensions ranged from 0.977 to 0.987. The correlation coefficient between scores of the SBS-C and the CS-C was 0.919 (P < .01).

CONCLUSIONS

The SBS-C is valid, reliable, and responsive and is suitable for assessing sedation in mechanically ventilated children in China.

IMPLICATIONS FOR PRACTICE

The SBS-C can be used for sedation assessment in mechanically ventilated children in China, guiding decision making and the provision of care, and optimizing patient safety.

Effect of spontaneous breathing on atelectasis during induction of general anaesthesia in infants: A prospective randomised controlled trial

BACKGROUND

Atelectasis occurs commonly during induction of general anaesthesia in children, particularly infants.

OBJECTIVES

We hypothesised that maintaining spontaneous ventilation can reduce atelectasis formation during anaesthetic induction in infants. We compared spontaneous ventilation and manual positive-pressure ventilation in terms of atelectasis formation in infants.

DESIGN

Randomised controlled study.

SETTING

Single tertiary hospital in Seoul, Republic of Korea, from November 2018 to December 2019.

PATIENTS

We enrolled 60 children younger than 1 year of age undergoing general anaesthesia, of whom 56 completed the study. Exclusion criteria were history of hypoxaemia during previous general anaesthesia, development of a respiratory tract infection within 1 month, current intubation or tracheostomy cannulation, need for rapid sequence intubation, preterm birth, age within 60 weeks of the postconceptional age and the presence of contraindications for rocuronium or sodium thiopental.

INTERVENTION

Patients were allocated randomly to either the 'spontaneous' group or 'controlled' group. During preoxygenation, spontaneous ventilation was maintained in the 'spontaneous' group while conventional bag-mask ventilation was provided in the 'controlled' group. After 5 min of preoxygenation, a lung ultrasound examination was performed to compare atelectasis formation in the two groups.

RESULTS

Atelectasis after preoxygenation was seen in seven (26.9%) of 26 patients in the 'spontaneous' group and 22 (73.3%) of 30 patients in the 'controlled' group (P = 0.001). The relative risk of atelectasis in the 'spontaneous' group was 0.39 (95% CI 0.211 to 0.723). Regarding ultrasound pictures of consolidation, the total score and sum of scores in the dependent regions were significantly lower in the 'spontaneous' group than in the 'controlled' group (P = 0.007 and 0.001, respectively).

CONCLUSION

Maintaining spontaneous ventilation during induction of general anaesthesia has a preventive effect against atelectasis in infants younger than 1 year of age, particularly in the dependent portions of the lungs.

TRIAL REGISTRATION

Clinicaltrials.gov (identifier: NCT03739697).

Prevention of atelectasis by continuous positive airway pressure in anaesthetised children: A randomised controlled study

BACKGROUND

Continuous positive airway pressure (CPAP) prevents peri-operative atelectasis in adults, but its effect in children has not been quantified.

OBJECTIVE

The aim of this study was to evaluate the role of CPAP in preventing postinduction and postoperative atelectasis in children under general anaesthesia.

DESIGN

A randomised controlled study.

SETTING

Single-institution study, community hospital, Mar del Plata. Argentina.

PATIENTS

We studied 42 children, aged 6 months to 7 years, American Society of Anesthesiologists physical status class I, under standardised general anaesthesia.

INTERVENTIONS

Patients were randomised into two groups: Control group (n = 21): induction and emergence of anaesthesia without CPAP; and CPAP group (n = 21): 5 cmH2O of CPAP during induction and emergence of anaesthesia. Lung ultrasound (LUS) imaging was performed before and 5 min after anaesthesia induction. Children without atelectasis were ventilated in the same manner as the Control group with standard ventilatory settings including 5 cmH2O of PEEP. Children with atelectasis received a recruitment manoeuvre followed by standard ventilation with 8 cmH2O of PEEP. Then, at the end of surgery, LUS images were repeated before tracheal extubation and 60 min after awakening.

MAIN OUTCOME MEASURES

Lung aeration score and atelectasis assessed by LUS.

RESULTS

Before anaesthesia, all children were free of atelectasis. After induction, 95% in the Control group developed atelectasis compared with 52% of patients in the CPAP group (P < 0.0001). LUS aeration scores were higher (impaired aeration) in the Control group than the CPAP group (8.8 ± 3.8 vs. 3.5 ± 3.3 points; P < 0.0001). At the end of surgery, before tracheal extubation, atelectasis was observed in 100% of children in the Control and 29% of the CPAP group (P < 0.0001) with a corresponding aeration score of 9.6 ± 3.2 and 1.8 ± 2.3, respectively (P < 0.0001). After surgery, 30% of children in the Control group and 10% in the CPAP group presented with residual atelectasis (P < 0.0001) also corresponding to a higher aeration score in the Control group (2.5 ± 3.1) when compared with the CPAP group (0.5 ± 1.5; P < 0.01).

CONCLUSION

The use of 5 cmH2O of CPAP in healthy children of the studied age span during induction and emergence of anaesthesia effectively prevents atelectasis, with benefits maintained during the first postoperative hour.

TRIAL REGISTRY

Clinicaltrials.gov NCT03461770.

Lung ultrasound score to determine the effect of fraction inspired oxygen during alveolar recruitment on absorption atelectasis in laparoscopic surgery: a randomized controlled trial

Background

Although the intraoperative alveolar recruitment maneuver (RM) efficiently treats atelectasis, the effect of Fio₂ on atelectasis during RM is uncertain. We hypothesized that a high Fio₂ (1.0) during RM would lead to a higher degree of postoperative atelectasis without benefiting oxygenation when compared to low Fio₂ (0.4).

Methods

In this randomized controlled trial, patients undergoing elective laparoscopic surgery in the Trendelenburg position were allocated to low- (Fio₂ 0.4, n = 44) and high-Fio₂ (Fio₂ 1.0, n = 46) groups. RM was performed 1-min post tracheal intubation and post changes in supine and Trendelenburg positions during surgery. We set the intraoperative Fio₂ at 0.4 for both groups and calculated the modified lung ultrasound score (LUSS) to assess lung aeration after anesthesia induction and at surgery completion. The primary outcome was modified LUSS at the end of the surgery. The secondary outcomes were the intra- and postoperative Pao₂ to Fio₂ ratio and postoperative pulmonary complications.

Results

The modified LUSS before capnoperitoneum and RM (P = 0.747) were similar in both groups. However, the postoperative modified LUSS was significantly lower in the low Fio₂ group (median difference 5.0, 95% CI 3.0–7.0, P < 0.001). Postoperatively, substantial atelectasis was more common in the high-Fio₂ group (relative risk 1.77, 95% CI 1.27–2.47, P < 0.001). Intra- and postoperative Pao₂ to Fio₂ were similar with no postoperative pulmonary complications. Atelectasis occurred more frequently when RM was performed with high than with low Fio₂; oxygenation was not benefitted by a high-Fio_2.

Conclusions

In patients undergoing laparoscopic surgery in the Trendelenburg position, absorption atelectasis occurred more frequently with high rather than low Fio₂. No oxygenation benefit was observed in the high-Fio₂ group.

Trial registration

ClinicalTrials.gov, NCT03943433. Registered 7 May 2019,