Dependency of respiratory system mechanics on positive end-expiratory pressure and recruitment maneuvers in lung healthy pediatric patients-A randomized crossover study

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-guided best positive end-expiratory pressure in neonatal anesthesia: a proposed randomized, controlled study

BACKGROUND

Atelectasis is a common complication in neonatal anesthesia. Lung ultrasound (LUS) can be used intraoperatively to evaluate and recognize atelectatic lung areas. Hypotheses for the study are: (1) The use of LUS to guide choice of best positive end-expiratory pressure (PEEP) can lead to reduction of FiO2 to achieve same saturations of oxygen (SpO2). (2) In a less de-recruited lung, there will be less postoperative pulmonary complications. (3) Static respiratory system compliance could be different. (4) Hemodynamic parameters and amount of fluids infused or need for vasopressors intraoperatively could be different.

METHODS

We propose a randomized controlled trial that compares standard PEEP settings with LUS-guided PEEP choice in patients under 2 months of age undergoing general anesthesia.

RESULTS

The primary aim is to determine whether LUS-guided PEEP choice in neonatal anesthesia, compared to standard PEEP choice, can lead to reduction of FiO2 applied to the ventilatory setting in order to maintain same SpO2s. Secondary aims are to determine whether patients treated with LUS-guided PEEP will develop less postoperative pulmonary complications, will have a significant difference in hemodynamic parameters and amount of fluids or vasopressors infused, and in static respiratory system compliance.

CONCLUSIONS

We expect a significant reduction of FiO2 in LUS-guided ventilation.

IMPACT

Lung atelectasis is extremely common in neonatal anesthesia, because of the physiology of the neonatal lung and chest wall and leads to hypoxemia, being a lung area with a perfusion/ventilation mismatch. Raising inspired fraction of oxygen can overcome temporarily hypoxemia but oxygen is a toxic compound for newborns. Lung ultrasound (LUS) can detect atelectasis at bedside and be used to optimize ventilator settings including choice of positive end-expiratory pressure (PEEP). This randomized controlled trial (RCT) aims at demonstrating that LUS-guided choice of best PEEP during neonatal anesthesia can lead to reduction of inspired fractions of oxygen to keep same peripheral saturations SpO2.

Understanding pediatric ventilation in the operative setting. Part II: Setting perioperative ventilation

Approaches toward lung-protective ventilation have increasingly been investigated in recent years. Despite evidence being found in adults undergoing surgery, data in younger children are still scarce and controversial. From a physiological perspective, however, the continuously changing characteristics of the respiratory system from birth through adolescence require an approach based on the analysis of each individual patient. The modern anesthesia workstation provides such information, with the technical strengths and weaknesses being discussed in a review preceding the present work (see Part I). The present summary aims to provide ideas on how to translate the information displayed on the anesthesia workstation to patient-oriented clinical ventilation settings.

Understanding pediatric ventilation in the operative setting. Part I: Physical principles of monitoring in the modern anesthesia workstation

The modern anesthesia workstation provides a wealth of information some of which is of particular interest when it comes to optimizing ventilation settings. This knowledge gains even more importance in the therapy of pediatric patients. In the absence of evidence-based recommendations on optimal ventilation settings in pediatric patients, the evaluation of individual factors becomes crucial and challenging at the same time. Even when equipped with the latest sensor technology, the user will always have to be in charge of interpreting the provided monitoring variables. The purpose of this review is to outline the clinical impact, technological background, and reliability of the most relevant information measured and calculated by a modern anesthesia workstation. It aims at translating the technical knowledge into a more competent and vigilant application in the clinical setting.

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 (V_T) 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/V_T 8 ml kg^-1 (PEEP8/V_T8), PEEP 10 cm H₂O/V_T 5 ml kg^-1 (PEEP10/V_T5), PEEP 10 cm H₂O/V_T 8 ml kg^-1 (PEEP10/V_T8), and PEEP 12 cm H₂O/V_T 5 ml kg^-1 (PEEP12/V_T5). 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/V_T5 (60.5%), compared with PEEP10/V_T8, PEEP8/V_T8, and PEEP12/V_T5 (23.3-34.9%; P<0.001). Decreasing compliance profiles were most frequent when V_T increased to 8 ml kg^-1, PEEP increased to 12 cm H₂O, or both. Plateau airway pressures were lower at PEEP8/V_T8 (16.9 cm H₂O [2.2]) and PEEP10/V_T5 (16.7 cm H₂O [1.7]), compared with PEEP10/V_T8 (19.5 cm H₂O [2.1]) and PEEP12/V_T5 (19.0 cm H₂O [2.0]; P<0.001). Driving pressure was lowest with PEEP10/V_T5 (4.6 cm H₂O), compared with other combinations (7.0 cm H₂O [2.0]-9.5 cm H₂O [2.1]; P<0.001).

CONCLUSIONS

V_T 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 V_T settings on postoperative pulmonary complications in children undergoing surgery requires further study.

CLINICAL TRIAL REGISTRATION

NCT04633720.