Background: Pulmonary atelectasis in anesthetized children is easily reverted by lung recruitment maneuvers. However, the high airways pressure reached during the maneuver could negatively affect hemodynamics. The aim of this study is to assess the effect and feasibility of a postural lung recruitment maneuver (P-RM); i.e., a new maneuver that opens up the atelectatic lung areas based on changing the child's body position under constant ventilation with moderated driving pressure (12 cmH 2 O) and of positive end-expiratory pressure (PEEP, 10 cmH 2 O). Forty ASA I-II children, aged 6 months to 7 years, subjected to general anesthesia were studied. Patients were ventilated with volume control mode using standard settings with 5 cmH 2 O of PEEP. They were randomized into two groups: (1) control group (C group, n = 20)-ventilation was turned to pressure control ventilation using a fixed driving pressure of 12 cmH 2 O. PEEP was increased from 5 to 10 cmH 2 O during 3 min maintaining the supine position. (2) P-RM group (n = 20)-patients received the same increase in driving pressure and PEEP, but they were placed, respectively, in the left lateral position, in the right lateral position (90 s each), and back again into the supine position after 3 min. Then, ventilation returned to baseline settings in volume control mode. Lung ultrasound-derived aeration score and respiratory compliance were assessed before (T1) and after (T2) 10 cmH 2 O of PEEP was applied. Results: At baseline ventilation (T1), both groups showed similar aeration score (P-RM group 9.9 ± 1.9 vs C group 10.4 ± 1.9; p = 0.463) and respiratory compliance (P-RM group 15 ± 6 vs C group 14 ± 6 mL/cmH 2 O; p = 0.517). At T2, the aeration score decreased in the P-RM group (1.5 ± 1.6 vs 9.9 ± 2.1; p < 0.001), but remained without changes in the C group (9.9 ± 2.1; p = 0.221). Compliance was higher in the P-RM group (18 ± 6 mL/cmH 2 O) when compared with the C group (14 ± 5 mL/cmH 2 O; p = 0.001). Conclusion: Lung aeration and compliance improved only in the group in which a posture change strategy was applied.

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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.

Protocol started on October 2014.

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Detrás de las acciones y estrategias de las personas para aprender o enseñar, existe un cuerpo teórico noexplícito, que se configura a partir de un conjunto de supuestos coherentes o incoherentes entre sí, en fun-ción de la relación que exista entre lo que el sujeto dice y lo que hace. Estas representaciones implícitas surgen no sólo de la educación formal recibida, sino de la propia historia educativa de cada sujeto y, en el caso de los docentes, orientan de un modo u otro su práctica, tal como lo indican numerosas investi-gaciones sobre el tema. En este trabajo se analizan las concepciones sobre el aprendizaje y la utilización de estrategias metacognitivas de dos grupos de estudiantes universitarios de profesorado, provenientes de distintas áreas disciplinares: ciencias humanas y ciencias exactas. Los resultados muestran dependencia de las concepciones de aprendizaje con respecto al dominio de formación disciplinar, situación que se da sólo parcialmente en el caso de la utilización de estrategias metacognitivas.