Hypoxemia in Young Children Undergoing One-lung Ventilation: A Retrospective Cohort Study

Abstract

Background One-lung ventilation in children remains a specialized practice with low case numbers even at tertiary centers, preventing an assessment of best practices. The authors hypothesized that certain case factors may be associated with a higher risk of intraprocedural hypoxemia in children undergoing thoracic surgery and one-lung ventilation. Methods The Multicenter Perioperative Outcomes database and a local quality improvement database were queried for documentation of one-lung ventilation in children 2 months to 3 yr of age inclusive between 2010 and 2020. Patients undergoing vascular or other cardiac procedures were excluded. All records were reviewed electronically for the presence of hypoxemia, oxygen saturation measured by pulse oximetry (Spo2) less than 90% for 3 min or more continuously, and severe hypoxemia, Spo2 less than 90% for 5 min or more continuously during one-lung ventilation. Records were also assessed for hypercarbia, end-tidal CO2 greater than 60 mmHg for 5 min or more or a Paco2 greater than 60 on arterial blood gas. Covariates assessed for association with these outcomes included age, weight, American Society of Anesthesiologists (Schaumburg, Illinois) Physical Status 3 or greater, duration of one-lung ventilation, preoperative Spo2 less than 98%, bronchial blocker versus endobronchial intubation, left operative side, video-assisted thoracoscopic surgery, lower tidal volume ventilation (tidal volume less than or equal to 6 ml/kg plus positive end expiratory pressure greater than or equal to 4 cm H2O for more than 80% of the duration of one-lung ventilation), and type of procedure. Results Three hundred six cases from 15 institutions were included for analysis. Hypoxemia and severe hypoxemia occurred in 81 of 306 (26%) patients and 56 of 306 (18%), respectively. Hypercarbia occurred in 153 of 306 (50%). Factors associated with lower risk of hypoxemia in multivariable analysis included left operative side (odds ratio, 0.45 [95% CI, 0.251 to 0.78]) and bronchial blocker use (odds ratio, 0.351 [95% CI, 0.177 to 0.67]). Additionally, use of a bronchial blocker was associated with a reduced risk of severe hypoxemia (odds ratio, 0.290 [95% CI, 0.125 to 0.62]). Conclusions Use of a bronchial blocker was associated with a lower risk of hypoxemia in young children undergoing one-lung ventilation. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Error traps in pediatric one‐lung ventilation

“…In the MPOG study previously mentioned, the rate of hypercarbia defined as an end-tidal carbon dioxide or PaCO 2 > 60 mm Hg on an arterial blood gas is 50% (95% CI, 44%-56%). 20 Using tidal volume <6 ml/kg, endobronchial intubation, VATS, and increased OLV duration were associated with an increased risk of hypercarbia. Fortunately, hypercarbia appears to be well tolerated in most children, with carbon dioxide levels returning to baseline levels fairly rapidly following reinstatement of two-lung ventilation.…”

“…In a recent multicenter perioperative outcomes group (MPOG) retrospective study looking at ventilation parameters in young children undergoing OLV, the median tidal volumes used for isolation ranged from 6.1 to 6.7 ml/kg, depending on the side of procedure and approach to OLV (endobronchial intubation vs. BB). 20 Interestingly, tidal volumes <6 ml/kg were not associated with an increased rate of hypoxemia. In this same study, the median FiO 2 during OLV with a BB and endobronchial intubation was 72% and 80%, respectively, in left-sided cases and 80% and 96%, respectively, in right-sided cases.…”

“…Regardless of the approach to OLV, typical goals during OLV include maintaining adequate oxygenation in the face of reduced compliance and frequently smaller tidal volumes. In a recent multicenter perioperative outcomes group (MPOG) retrospective study looking at ventilation parameters in young children undergoing OLV, the median tidal volumes used for isolation ranged from 6.1 to 6.7 ml/kg, depending on the side of procedure and approach to OLV (endobronchial intubation vs. BB) 20 . Interestingly, tidal volumes <6 ml/kg were not associated with an increased rate of hypoxemia.…”

“…Hypoxemia, which is defined as a decrease in oxygen saturation to <90% or an arterial oxygen tension (PaO 2 ) <60 mm Hg when the patient is being ventilated at an FiO 2 of 1.0, is common during OLV 18,22 . In a recent multicenter study, the risk of hypoxemia in young children undergoing OLV was 26%, and the incidence of severe hypoxemia, defined as an oxygen saturation <90% for 5 min or more, was 18% 20 . Hypoxemia during OLV is caused by the obligatory shunting of blood from the nondependent lung, and V/Q mismatch in the dependent lung.…”

“…Further, peak inspiratory pressures in young children should range from 21 to 24 cm H 2 O. 20 Additionally, because compliance, and therefore, ventilation, may be impaired in some patients, the clinician must be aware of the relatively high risk of hypercarbia during OLV.…”