The research focused on 102 infants with congenital pulmonary airway malformation, or CPAM, a developmental lung abnormality characterized by adenomatous overgrowth of the terminal bronchioles. CPAM accounts for roughly 40 percent of pediatric thoracoscopic lobectomies, making these infants a well-defined and clinically important population. All of the children, aged between birth and twelve months, underwent elective thoracoscopic lung resection between January 2022 and February 2025. After excluding nine patients for reasons including incomplete data, abandonment of one-lung ventilation, conversion to open surgery, or postoperative intensive care transfer, the researchers analyzed 93 infants divided into two groups based on the ventilator strategy actually delivered during surgery.

The dividing line between the groups was positive end-expiratory pressure, or PEEP, the pressure maintained in the airways at the end of each breath to keep the tiny air sacs of the lungs from collapsing. One group received a conventional fixed PEEP of 5 centimeters of water throughout one-lung ventilation, a standard choice in anesthetic practice meant to maintain basic alveolar recruitment. The other group received individualized PEEP titration guided by dynamic lung compliance, a physiological parameter that reflects the elasticity of lung tissue and the resistance of the airways. Compliance-guided titration works on a straightforward principle: the anesthesiologist increases PEEP step by step and measures how easily the lungs inflate at each level, then selects the lowest pressure at which compliance reaches its maximum, indicating optimal alveolar recruitment without overdistension.

The titration protocol was meticulous. After lung recruitment maneuvers, infants in the protocol-guided group started at zero PEEP, and the pressure was increased by 1 centimeter of water every ten respiratory cycles up to a maximum of 10 centimeters of water. At each step, dynamic compliance was calculated as the delivered tidal volume divided by the difference between peak airway pressure and PEEP. The pressure level yielding the highest compliance was then maintained for the remainder of one-lung ventilation. In practice, this individualized approach settled on a mean PEEP of about 7.1 centimeters of water, notably higher than the fixed 5 centimeters of water used in the conventional group. Ventilation itself followed a volume-controlled protocol with an inspired oxygen concentration of 0.5, a fresh gas flow of 2 liters per minute, and tidal volumes of 6 milliliters per kilogram during single-lung phases, with a bronchial blocker positioned under bronchoscopic guidance to isolate the operative lung.

The intraoperative results revealed a clear physiological advantage for the compliance-guided strategy. Using repeated-measures analysis of variance with group-by-time interaction as the principal inferential test, the researchers found significant differences in dynamic compliance, the ratio of arterial oxygen partial pressure to inspired oxygen fraction, and the alveolar-arterial oxygen gradient, a sensitive marker of gas exchange efficiency. At the measurement points thirty and sixty minutes after PEEP was established, compliance-guided infants showed substantially higher lung compliance, better oxygenation ratios, and smaller oxygen gradients than those on fixed PEEP. Notably, these benefits persisted even fifteen minutes after both lungs were returned to shared ventilation, suggesting that the individualized pressure settings had left the lungs in a better functional state. Crucially, heart rate, mean arterial pressure, and plateau pressure showed no significant between-group differences, indicating that the improved gas exchange came without hemodynamic cost.

The study’s primary outcome, however, lay beyond the operating room. The researchers turned to the Nursing Activities Score, or NAS, a validated instrument originally proposed by Miranda and colleagues in 2003 and tested across 99 intensive care units in 15 countries. The scale comprises 23 items that together estimate the percentage of a nurse’s time devoted to direct patient care over a 24-hour period, with a total score of 100 percent representing the work of one full-time nurse. Prior multicenter work has shown that NAS can account for 75 to 90 percent of the actual workload of intensive care nurses. In this study, attending PACU nurses prospectively recorded NAS for every infant throughout the recovery stay, with all 23 items applicable and no missing data.

The findings were striking. In the unadjusted analysis, infants managed with compliance-guided PEEP had a mean NAS of 24.10 points compared with 27.99 points in the conventional group, a difference of 3.89 points. After statistical adjustment for age, sex, body mass index, American Society of Anesthesiologists physical status, lesion laterality, and duration of one-lung ventilation, the adjusted mean difference remained significant at 3.75 points, with a 95 percent confidence interval spanning from 6.44 down to 1.07 points and a p-value of 0.007. The overall regression model was statistically significant, and no problematic collinearity was detected among the covariates. Although the minimal clinically important difference for NAS in a pediatric recovery unit has not been formally established, the authors interpret this difference as suggesting a genuinely lower observed nursing workload, encompassing reduced demands for monitoring, repositioning, medication administration, fluid management, and emergency resuscitation.

Supporting secondary outcomes reinforced the picture. Infants in the compliance-guided group were extubated roughly 3.3 minutes sooner on average and spent about 5.3 fewer minutes in the PACU, both differences statistically significant. Most notably, the composite rate of recorded adverse events, defined a priori as any occurrence of laryngospasm, coughing, hypoxemia, nausea and vomiting, or bradycardia, was 6.5 percent in the compliance-guided group versus 23.4 percent in the conventional group, an odds ratio of 0.23 with a Fisher’s exact p-value of 0.040. Hypoxemia, defined as oxygen saturation below 90 percent, was recorded in one infant in the guided group compared with six in the conventional group, though this individual comparison did not reach statistical significance given the small numbers. Measures of emergence delirium using the Paediatric Anaesthesia Emergence Delirium scale and pain using the FLACC scale showed no significant differences, nor did the need for propofol or pentazocine rescue medication. Postoperative hospital stay trended about 1.1 days shorter in the guided group but did not reach significance.

Exploratory subgroup analyses across age, lesion location, and duration of one-lung ventilation found no statistically significant heterogeneity in the association, with all interaction p-values exceeding 0.05, hinting that the benefit may be broadly consistent across these patient characteristics. The authors are careful, however, to frame their conclusions within the study’s limitations. The retrospective, single-center design and modest sample size mean residual and unmeasured confounding cannot be excluded. Post-exposure exclusions may have introduced selection bias, and a formal sensitivity analysis was not feasible because so few events occurred. The NAS instrument itself was developed for intensive care settings, and its validity in the infant recovery room remains uncertain, while total scores may also be influenced by the length of the PACU stay itself. Sparse adverse events and subgroup comparisons were underpowered, and the confidence interval around the adjusted NAS difference was relatively wide.

Even with those caveats, the study offers a compelling glimpse of how a physiological measurement made at the bedside of an anesthetized infant can echo through the entire perioperative journey. By tailoring PEEP to each child’s own lung mechanics rather than applying a one-size-fits-all pressure, anesthesiologists may achieve more homogeneous alveolar recruitment, less ventilation-perfusion mismatch, and a reduced risk of ventilator-induced lung injury, and the downstream effects appear to include smoother recoveries, fewer complications, and lighter nursing burdens in the critical first hour after surgery. The authors describe their findings as hypothesis-generating and call for confirmation in prospective studies, but the message for perioperative teams is clear: the ventilator settings chosen in the operating room may be among the most powerful determinants of what unfolds in the recovery unit, and individualizing them could transform care for the smallest surgical patients.

Subject of Research: Compliance-guided positive end-expiratory pressure during one-lung ventilation in infants and its association with post-anaesthesia care unit nursing workload and recovery outcomes

Article Title: Association Between Cdyn‐Guided PEEP and Nursing Activities During PACU Recovery in Infants Undergoing One‐Lung Ventilation: A Retrospective Observational Cohort Study

Article References: Hao, M., Zhang, B., Han, Y., Zhao, C., Dong, Z., & Song, B. (2026). Association Between Cdyn‐Guided PEEP and Nursing Activities During PACU Recovery in Infants Undergoing One‐Lung Ventilation: A Retrospective Observational Cohort Study. Nursing Open, 13(10), Article e70935. https://doi.org/10.1002/nop2.70935

Image Credits: AI Generated

DOI: 10.1002/nop2.70935

Keywords: one-lung ventilation, PEEP titration, dynamic lung compliance, infants, thoracoscopic surgery, PACU, Nursing Activities Score, lung-protective ventilation, congenital pulmonary airway malformation, pediatric anesthesia, oxygenation, adverse events