Clinical effects of bi-level positive airway pressure and heated humidified high flow nasal cannula ventilation as initial treatment for premature infants with respiratory distress syndrome / 中国新生儿科杂志

Objective:To compare the efficacy and safety of bi-level positive airway pressure (BiPAP) ventilation and heated humidified high flow nasal cannula (HHHFNC) ventilation as initial respiratory support for premature infants with respiratory distress syndrome (RDS).Methods:From January 2019 to June 2021, premature infants [gestational age (GA) 28~35 weeks)] with grade Ⅰ to Ⅲ RDS admitted to Suining County People's Hospital were prospectively enrolled. The infants were randomly assigned into BiPAP group and HHHFNC group. The clinical characteristics, ventilation efficacy and complications were analyzed.Results:A total of 33 infants were in BiPAP group and 32 in HHHFNC group. No significant differences existed between the two groups in the following items: the frequency of apnea within 24 h of ventilation, FiO 2 and PaCO 2 at 24 h, the use of pulmonary surfactant (PS), the incidence of non-invasive ventilation failure within 72 h, non-invasive ventilation duration and the age achieving total enteral nutrition. HHHFNC group had lower score in premature infants pain profile (PIPP) than BiPAP group at 24 h of non-invasive ventilation [4 (3, 6) vs. 8 (6, 11), P<0.001]. No significant differences existed in nasal injury, pneumothorax, intraventricular hemorrhage, necrotizing enterocolitis, bronchopulmonary dysplasia and mortality rate between the two groups ( P>0.05). Conclusions:As the initial treatment for premature infants with grade Ⅰ to Ⅲ RDS, BiPAP and HHHFNC has similar rates of non-invasive ventilation failure within 72 h,non-invasive ventilation duration and adverse events. HHHFNC may ease the pain of the infants.

Effect of driving pressure-guided PEEP titration on lung injury in elderly patients undergoing robot-assisted radical prostatectomy / 中华麻醉学杂志

Objective:To evaluate the effect of driving pressure (ΔP)-guided PEEP titration on lung injury in elderly patients undergoing robot-assisted radical prostatectomy (RARP).Methods:Forty-six American Society of Anesthesiologists physical status Ⅱ or Ⅲ patients, aged 65-80 yr, with body mass index of 19-28 kg/m 2, with Assess Respiratory Risk in Surgical Patients in Catalonia score assessed as medium to high risk, scheduled for elective RARP, were divided into control group (group C, n=23) and ΔP titration group (group D, n=23) using a random number table method.Volume-controlled mechanical ventilation was used after anesthesia induction and tracheal intubation.In group C, 5 cmH 2O was used to fix PEEP.In group D, the optimal PEEP was titrated after computer-controlled breathing and after establishing Trendelenburg position and pneumoperitoneum, the first titration started from 4 cmH 2O and increased by 1 cmH 2O every 4 min until ΔP reached the minimum value or PEEP increased to 12 cmH 2O, and the second titration was increased in increments as the method described above based on the optimal PEEP of the first titration.At 4 min after completion of the first PEEP titration (T 1, 4 min after mechanical ventilation with fixed PEEP in group C), 2 h after establishment of Trendelenburg position (T 2), 1 min after extubation (T 3) and 2 h after operation (T 4), serum concentrations of Clara cell protein (CC16), surfactant protein D (SP-D), soluble receptor for advanced glycation end-products (sRAGE) and soluble intercellular adhesion molecule-1 (sICAM-1). Pulmonary complications were assessed within 7 days after operation. Results:The serum concentrations of CC16, SP-D, sRAGE and sICAM-1 were significantly higher at T 2-4 than at T 1 in two groups ( P<0.05). Compared with group C, the serum concentrations of CC16, SP-D, sRAGE and sICAM-1 were significantly decreased at T 2-4 ( P<0.05), and no significant change was found in the incidence of pulmonary complications within 7 days after operation in group D ( P>0.05). Conclusions:ΔP-guided PEEP titration can reduce lung injury in elderly patients undergoing RARP.

T-piece resuscitator versus self-inflating bag for positive pressure ventilation during neonatal resuscitation / 中华围产医学杂志

To compare the performance of self-inflating bag (SIB) with T-piece resuscitator (TPR) in neonatal resuscitation.Methods:This study involved the trainees participating in a Neonatal Resuscitation Simulation Camp (NRSC) organized by Shanghai First Maternity and Infant Hospital in December 2019. They were trained to provide positive pressure ventilation with the two devices on artificial lungs. Ventilation parameters including peak inspiratory pressure (PIP), positive end-expiratory pressure (PEEP), PIP in pulmonary alveoli (PIP alv), mean airway pressure (MAP), frequency, inspiratory time (Ti), tidal volume and minute ventilation volume were recorded and analyzed by independent sample t-test or rank sum test. Results:The PIP alv, PIP, oxygen flow rate, tidal volume and minute ventilation volume delivered by TPR were significantly lower than those by SIB [(17.18±1.61) vs (24.05±4.29) cmH 2O (1 cmH 2O=0.098 kPa), t=－6.87; (17.91±1.35) vs (29.97±4.50) cmH 2O, t=－14.06; (3.65±0.25) vs (6.88±1.59) L/min, t=－11.33; (15.90±1.81) vs (24.02±4.29) ml/min, t=－10.99; (664.71±88.94) vs (1 069.49±205.68) ml/min, t=－9.89; all P<0.001]. However, compared with SIB, the PEEP in pulmonary alveoli, Ti, duration of ventilation, inspiratory to expiratory ratio were increased when using TPR [(4.76(4.69-5.57) vs 0.19(0.12-4.10) cmH 2O, T=1 190.00; (0.59±0.15) vs (0.43±0.09) s, t=5.01; (1.46±0.23) vs (1.36±0.11) s, t=2.15; 0.71±0.22 vs 0.47±0.13, t=5.14; all P<0.05]. Conclusion:TPR could deliver more stable and safer PIP, PEEP and tidal volume than SIB and keeping MAP at a stable level during positive pressure ventilation on artificial lungs.

Effects of noninvasive positive pressure ventilation on cardiac function in premature infants using Tei index combined with correction of QT dispersion and B-type natriuretic peptide: a prospective study / 中华围产医学杂志

Objective:To assess the effects of noninvasive positive pressure ventilation on premature infants' cardiac function using Tei index combined with corrected QT dispersion (QTcd) and B- type natriuretic peptide (BNP).Methods:This prospective study involved premature infants from 28 to 32 weeks of gestational age diagnosed with respiratory distress syndrome (RDS) and treated with noninvasive positive pressure ventilation in the Neonatal Intensive Care Unit of Xuzhou Central Hospital from December 2017 to December 2020. According to the mean airway pressure (MAP) during noninvasive positive pressure ventilation, the patients were divided into the low-pressure group (≤6 cmH 2O, 1 cmH 2O=0.098 kPa), medium-pressure group (>6-<9 cmH 2O), and high-pressure group (≥9 cmH 2O). The right ventricular Tei index, QTcd, and blood BNP were monitored during the first 2 h of noninvasive positive pressure ventilation and 12 h after continuous ventilation with stable MAP. Chi-square test, one-way analysis of variance, paired t-test, and Pearson product-moment correlation coefficient were adopted for statistical analysis. Results:Totally 178 premature infants were enrolled, including 75 in the low-pressure, 62 in the medium-pressure, and 41 in the high-pressure group. After continuous ventilation with stable MAP for 12 h, the right ventricle Tei index and QTcd in the high-pressure group were higher than those in the medium- and low-pressure group [Tei index: (0.38±0.05) vs (0.33±0.04) and (0.33±0.04), F=29.18; QTcd: (27.6±4.2) vs (22.8±4.4) and (22.2±4.2) ms, F=23.26, all P<0.001], and the comparison between the medium- and the low-pressure group did not differ significantly. No significant difference was observed in blood BNP levels among the three groups ( F=1.33, P=0.267). The right ventricle Tei index and QTcd increased in the high-pressure group after continuous ventilation with stable MAP for 12 h as compared with those within the first 2 h of noninvasive positive pressure ventilation [Tei index: (0.38±0.05) vs (0.34±0.04), t=－6.61; QTcd: (27.6±4.2) vs (23.4±4.4) ms, t=－5.06, all P<0.001]. However, the figures did not change significantly in the medium- or the low-pressure group (all P>0.05). There were no significant changes in blood BNP in the three groups (all P>0.05). The right ventricle Tei index and QTcd were moderately positively correlated with MAP ( r=0.56 and 0.50, both P<0.001). Conclusions:For the premature infants with RDS, noninvasive positive pressure ventilation has no significant effect on the cardiac function when MAP is less than 9 cmH 2O, but would have a certain effect on the right ventricular function when used at higher pressure (MAP≥9 cmH 2O) and for longer time (>12 h).

Effects of non-invasive positive pressure ventilation on plasma B-type natriuretic peptide level and Tei index of right ventricle in preterm infants / 中华全科医师杂志

Objective:To investigate the effects of non-invasive positive pressure ventilation (NPPV) on plasma B-type natriuretic peptide (BNP) level and Tei index of right ventricle in preterm infants.Methods:Premature infants of gestational age<34 weeks with respiratory distress syndrome who were admitted in Neonatal Intensive Care Unit of Xuzhou Central Hospital and requiring for NPPV from December 2018 to October 2020, were enrolled in the study. Patients were randomly divided into two groups 46 patients received nasal continuous positive airway pressure ventilation (NCPAP group) and 49 patients received bi-level positive airway pressure ventilation (BiPAP group); 42 preterm infants of gestational age<34 weeks and without NPPV were selected as the control group. The plasma BNP, Tei index of right ventricle, mean airway pressure and oxygen index at 0-12 h and 48-60 h after NPPV were monitored in NCPAP group and BiPAP group. The plasma BNP and Tei index of right ventricle at 0-12 h and 48-60 h after admission were monitored in the control group. SPSS 20.0 statistical software was used for data analysis.Results:(1)The plasma BNP and Tei index of right ventricle at 48-60 h after NPPV were significantly higher than those at 0-12 h after NPPV in NCPAP group and BiPAP group [NCPAP group: (287.5±155.5) vs. (179.9±102.3) ng/L, (0.43±0.08) vs. (0.38±0.06); BiPAP group: (303.1±135.4) vs. (186.5±95.6) ng/L, (0.45±0.08) vs. (0.39±0.06); t=6.00, 3.34, 7.47, 4.48; all P<0.05]. There were no significant differences in the plasma BNP and Tei index of right ventricle at 48-60 h and 0-12 h after admission in the control group [(181.9±86.8) vs. (169.5±78.9) ng/L, (0.34±0.05) vs. (0.36±0.05); t=0.83, -1.59; all P>0.05].(2) There were no significant differences in the plasma BNP and Tei index of right ventricle at 48-60 h after NPPV between NCPAP group-and BiPAP group (all P>0.05), but they were significantly higher than those in control group at 48-60 h after admission(all P<0.05). (3)The mean airway pressure and oxygen index at 48-60 h after NPPV in NCPAP group and BiPAP group showed a decrease trend compared to those at 0-12 h after NPPV, but the differences were not significant [NCPAP group: (6.8±1.2) vs. (7.0±1.3) cmH 2O(1 cmH 2O=0.098 kPa), (5.7±2.1) vs. (6.1±2.3); BiPAP group: (7.0±1.3) vs. (7.2±1.2) cmH 2O, (5.5±2.0) vs. (5.8±2.1); t=-1.05, -0.80, -1.88, -0.67; all P>0.05]; while there were no significant differences between the two groups (all P>0.05). (4)There was a positive correlation between the plasma BNP and mean airway pressure ( r=0.48, P<0.001), but no correlation between Tei index of right ventricle and mean airway pressure ( r=0.17, P=0.119) at 48-60 h after NPPV. Conclusion:The cardiac function indexes such as plasma BNP and Tei index of right ventricle in preterm infants are increased at 48-60 h after NPPV. When mean airway pressure is the same, the effects of NCPAP and BiPAP on plasma BNP and Tei index of right ventricle in preterm infants are similar.

Effects of driving pressure-guided individualized PEEP ventilation on intraoperative cardiac function in elderly patients undergoing laparoscopic surgery / 中华麻醉学杂志

Objective:To evaluate the effect of driving pressure-guided individualized PEEP ventilation on intraoperative cardiac function in elderly patients undergoing laparoscopic surgery.Methods:Seventy American Society of Anesthesiologists physical statusⅠor Ⅱ patients, aged 60-75 yr, with body mass index of 18-25 kg/m 2, with left ventricular ejection fraction (LVEF)>50%, undergoing elective laparoscopic radical gastrectomy under general anesthesia, were divided into 2 groups ( n=35 each) by the random number table method: conventional PEEP ventilation group (group P) and driving pressure-guided individualized PEEP ventilation group (group D). The patients were mechanically ventilated in the volume-controlled ventilation mode, with a V T of 7 ml/kg, an inspired oxygen concentration of 60%, an inspiratory/expiratory ratio of 1∶2, and an end-inspiratory pause time of 10%.In group P, 5 cmH 2O PEEP was given for ventilation from 5 min after the establishment of pneumoperitoneum until the end of operation.In group D, driving pressure-guided individualized PEEP titration was performed at 5 min after the establishment of pneumoperitoneum, and ventilation was maintained with the titrated individualized PEEP until the pneumoperitoneum was closed.After the pneumoperitoneum was closed, group D underwent driving pressure-directed individualized PEEP again, and ventilation was maintained with re-titrated PEEP until the end of surgery.Before pneumoperitoneum (T 0), at 5 min after establishment of pneumoperitoneum (T 1), 5 min of PEEP ventilation (T 2), 30 min of PEEP ventilation (T 3) and 5 min after the end of pneumoperitoneum (T 4), MAP was recorded, LVEF, global longitudinal strain of left ventricle, tricuspid annular systolic displacement, early diastolic peak velocity (E peak) of mitral valve and tricuspid valve orifice, early diastolic peak velocity (e′) and systole peak velocity (S′) of mitral valve and tricuspid valve annulus were measured using transesophageal ultrasonography, and myocardial performance index (MPI) and E/e′ were calculated. Results:Compared with group P, MAP, LVEF, mitral valve annulus S′, global longitudinal strain of left ventricle, tricuspid valve annulus S′, and tricuspid annular systolic displacement were significantly decreased at T 2 and T 3, and left ventricular MPI, mitral valve E/e′, right ventricular MPI and tricuspid E/e′ were increased in group D ( P<0.05). Conclusions:Driving pressure-guided individualized PEEP ventilation can decrease the cardiac function during pneumoperitoneum in elderly patients undergoing laparoscopic surgery.

Lesão renal aguda em pacientes críticos em ventilação mecânica com pressão positiva / Lesión renal aguda en pacientes críticos en ventilación mecánica con presión positiva / Acute kidney injury in critically ill patients on positive pressure mechanical ventilation

Resumo Objetivo Avaliar o efeito do uso de ventilação mecânica com pressão positiva expiratória final (PEEP) na função renal dos pacientes internados em Unidade de Terapia Intensiva (UTI). Métodos Estudo de coorte retrospectivo, quantitativo, desenvolvido na UTI de um hospital público de Brasília, Distrito Federal. A amostra foi constituída de 52 prontuários de pacientes internados na UTI de novembro de 2016 a dezembro de 2018. A coleta dos dados foi realizada por meio de um questionário com dados demográficos, clínicos e laboratoriais. Os pacientes foram alocados em grupos: (1) PEEP ≤ 5 cmH2O, (2) PEEP > 5 cmH2O e < 10 cmH2O e (3) PEEP ≥ 10 cmH2O. Resultados A média de idade dos pacientes foi de 59 anos e 50% deles tinha mais de 63 anos. Constatou-se que 63,16% dos pacientes que estavam em ventilação mecânica com pressão positiva ao final da expiração ≥ 10 cmH2O evoluíram no estágio 1 (menor gravidade de lesão renal aguda (LRA)) e 21,5% no estágio 2 (moderada gravidade). Ainda assim, um pequeno percentual (5,8%) de pacientes evoluiu a óbito. Pacientes sem sucesso no desmame da ventilação mecânica apresentaram 10,24 vezes a chance de evoluir com LRA. Conclusão o emprego da ventilação mecânica pode determinar danos à função renal dos pacientes internados em unidade de terapia intensiva e que aqueles com maior necessidade de oferta de PEEP evoluíram com diferentes gravidades e persistência da LRA.

Resumen Objetivo Evaluar el efecto del uso de la ventilación mecánica con presión positiva espiratoria final (PEEP) en la función renal de los pacientes internados en Unidad de Cuidados Intensivos (UTI). Métodos Estudio de corte retrospectivo, cuantitativo, desarrollado en la UCI de un hospital público de Brasília, Distrito Federal. La amuestra estuvo constituida por 52 prontuarios de pacientes internados en la UCI de noviembre de 2016 a diciembre de 2018. La recolección de los datos se realizó por medio de un cuestionario con datos demográficos, clínicos y laboratoriales. Los pacientes fueron distribuidos en grupos: (1) PEEP ≤ 5 cmH2O, (2) PEEP > 5 cmH2O y < 10 cmH2O y (3) PEEP ≥ 10 cmH2O. Resultados El promedio de edad de los pacientes era de 59 años y el 50 % de ellos tenía más de 63 años. Se constató que el 63,16 % de los pacientes que estaban en ventilación mecánica con presión positiva al final de la expiración ≥ 10 cmH2O evolucionaron en la etapa 1 (menor gravedad de lesión renal aguda (LRA)) y 21,5 % en la etapa 2 (moderada gravedad). Aun así, un pequeño porcentaje (5,8 %) de pacientes falleció. Pacientes sin éxito en la descontinuación de la ventilación mecánica presentaron 10,24 veces la posibilidad de evolucionar con LRA. Conclusión el uso de la ventilación mecánica puede determinar daños a la función renal de los pacientes internados en una unidad de cuidados intensivos y que los que tengan una mayor necesidad de oferta de PEEP evolucionaron con distintas gravedades y persistencia de la LRA.

Abstract Objective To assess the effect of using mechanical ventilation with positive end-expiratory pressure (PEEP) on the renal function of patients admitted to the Intensive Care Unit (ICU). Methods This is a quantitative retrospective cohort study developed in the ICU of a public hospital in Brasília, Distrito Federal. The sample consisted of 52 medical records of patients admitted to the ICU from November 2016 to December 2018. Data collection was performed through a questionnaire with demographic, clinical and laboratory data. Patients were allocated in two groups: (1) PEEP ≤ 5 cmH2O, (2) PEEP > 5 cmH2O and < 10 cmH2O, and (3) PEEP ≥ 10 cmH2O. Results The mean age of patients was 59 years and 50% of them were over 63 years. It was found that 63.16% of patients who were on mechanical ventilation with positive end-expiratory pressure ≥ 10 cmH2O evolved in stage 1 (less severe acute kidney injury (AKI)) and 21.5% in stage 2 (moderate gravity). Even so, a small percentage (5.8%) of patients died. Patients who were unsuccessful in weaning from mechanical ventilation had a 10.24-fold chance of developing AKI. Conclusion mechanical ventilation use can cause damage to the renal function of patients hospitalized in the intensive care unit and that those with greater need to offer PEEP evolved with different severities and persistence of AKI.

Damage control in the emergency department, a bridge to life / Control de daños en la sala de emergencias: un puente hacia la vida

Abstract Patients with hemodynamic instability have a sustained systolic blood pressure less or equal to 90 mmHg, a heart rate greater or equal to 120 beats per minute and an acute compromise of the ventilation/oxygenation ratio and/or an altered state of consciousness upon admission. These patients have higher mortality rates due to massive hemorrhage, airway injury and/or impaired ventilation. Damage control resuscitation is a systematic approach that aims to limit physiologic deterioration through strategies that address the physiologic debt of trauma. This article aims to describe the experience earned by the Trauma and Emergency Surgery Group (CTE) of Cali, Colombia in the management of the severely injured trauma patient in the emergency department following the basic principles of damage control surgery. Since bleeding is the main cause of death, the management of the severely injured trauma patient in the emergency department requires a multidisciplinary team that performs damage control maneuvers aimed at rapidly controlling bleeding, hemostatic resuscitation, and/or prompt transfer to the operating room, if required.

Resumen Un paciente politraumatizado hemodinámicamente inestable es aquel que ingresa al servicio de urgencias con una presión arterial sistólica menor o igual de 90 mmHg, una frecuencia cardiaca mayor o igual a 120 latidos por minuto y un compromiso agudo de la relación ventilación/oxigenación y/o del estado de conciencia. Por esta razón, existe una alta mortalidad dentro de las primeras horas de un trauma severo ya sea por una hemorragia masiva, una lesión de la vía aérea y/o una alteración de la ventilación. Siendo el objetivo de este artículo describir el manejo en urgencias del paciente politraumatizado hemodinámicamente inestable de acuerdo con los principios de control de daños. El manejo del paciente politraumatizado es una estrategia dinámica de alto impacto que requiere de un equipo multidisciplinario de experiencia. El cual debe de evolucionar conjunto a las nuevas herramientas de diagnóstico y tratamiento endovascular que buscan ser un puente para lograr una menor repercusión hemodinámica en el paciente y una más rápida y efectiva estabilización con mayores tasas de sobrevida.

Effect of individualized PEEP on postoperative lung complications in patients undergoing cardiac valve replacement / 中华麻醉学杂志

Objective:To investigate the effect of individualized positive end-expiratory pressure (PEEP) on postoperative lung complications in patients undergoing cardiac valve replacement.Methods:Sixty-four patients of both sexes, aged 40-70 yr, with body mass index of 18-26 kg/m 2, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ, with New York Heart Association class Ⅱ or Ⅲ, undergoing elective cardiac valve replacement (single or double) from July to October 2020, were enrolled in this study.The patients were divided into 2 groups ( n=32 each) using a random number table method: control group (group C) and individualized PEEP group (group P). After recruitment maneuver, group C was set with a fixed PEEP of 4 cmH 2O, group P was titrated using a PEEP-step method, and PEEP was set at 4 cmH 2O after admission to intensive care unit (ICU). Before induction of anesthesia (T 0), before recruitment maneuver (T 1), at 20 min after PEEP ventilation (T 2), at 2 h after surgery (T 3), and at 24 h after surgery (T 4), arterial blood samples were taken for determination of serum interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) concentrations.The hemodynamic indicators (heart rate, mean arterial pressure and central venous pressure) at T 1-T 4 were recorded.Pulmonary complications were diagnosed according to clinical manifestations, imaging and blood gas analysis during the postoperative hospitalization.The postoperative length of hospital stay, extubation time and duration of ICU stay were recorded. Results:PEEP in group P [(6.1±1.4)cmH 2O] was significantly higher than that in group C ( P<0.05). Compared with group C, the concentrations of serum IL-6 and TNF-α at T 3 were significantly decreased, central venous pressure at T 2 was increased, and the incidence of postoperative pulmonary complications was decreased ( P<0.05), and no significant change was found in the length of hospital stay, extubation time and duration of ICU stay in group P ( P>0.05). Conclusion:Early application of individualized PEEP after termination of cardiopulmonary bypass can decrease the risk of postoperative pulmonary complications in patients undergoing cardiac valve replacement.

Effect of driving pressure-guided individualized PEEP titration on atelectasis in elderly patients undergoing robot-assisted radical prostatectomy / 中华麻醉学杂志

Objective:To evaluate the effect of driving pressure-guided individualized positive end-expiratory pressure (PEEP) titration on atelectasis in elderly patients undergoing robot-assisted radical prostatectomy.Methods:Fifty elderly patients, aged 65-80 yr, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ, with body mass index of 19-28 kg/m 2, undergoing elective robot-assisted radical prostatectomy under general anesthesia, were divided into 2 groups ( n=25 each) according to the random number table method: traditional lung-protective ventilation group (group C) and driving pressure-guided individualized PEEP group (group D). The method for setting PEEP was as follows: PEEP 5 cmH 2O was used throughout operation in group C. In group D, the optimal PEEP was titrated after intubation and mechanical ventilation and Trendelenburg position-pneumoperitoneum construction, the initial value was the lowest PEEP allowed by the anesthesia machine, the PEEP was increased by 1 cmH 2O (PEEP≤12 cmH 2O) every 4 min, the plateau pressure and PEEP were simultaneously recorded to calculate the driving pressure, and the corresponding PEEP was considered as the optimal PEEP for the individual when the driving pressure reached the minimum.Ultrasound examination was performed after catheterization of radial artery (T 0), after anesthesia induction (T 1), 4 min after developing optimal PEEP ventilation (T 2, 4 min after developing ventilation in group C), after restoration of body position (T 3), before extubation (T 4), and at 2 h after admission to postanesthesia care unit (T 5). Atelectatic aeration loss scores were recorded at T 0, T 1, T 4 and T 5.Bilateral optic nerve sheath diameter was measured at T 0-4.Arterial blood gas analysis was performed at T 0, T 2, T 3 and T 5, PaO 2 and PaCO 2 were recorded, and oxygenation index was calculated.The postoperative pulmonary complications within 3 days after operation were recorded. Results:Compared with group C, atelectasis aeration loss scores at T 4, 5 and PaCO 2 at T 2, 3 were significantly decreased, and PaO 2 and oxygenation index were increased at T 2, 3, 5 in group D ( P<0.05). There were no significant differences in the bilateral optic nerve sheath diameter and incidence of postoperative pulmonary complications between the two groups ( P>0.05). Conclusion:Driving pressure-guided individualized PEEP can increase intraoperative oxygenation and decrease the development of atelectasis in elderly patients undergoing robot-assisted radical prostatectomy.

Efficacy of left parapharyngeal pressure combined with cricoid pressure in preventing gastric insufflation during positive pressure ventilation by facemask / 中华麻醉学杂志

Objective:To compare the efficacy of left parapharyngeal pressure (PLP) combined with cricoid pressure in preventing gastric insufflation during positive pressure ventilation by facemask.Methods:Two hundred and forty patients of both sexes, aged 18-75 yr, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ, undergoing surgery under general anesthesia requiring endotracheal intubation, were selected and randomly divided into 4 groups ( n=60 each) using a random number table method: cricoid pressure group (group CP), left PLP group (group LP), cricoid pressure combined with left PLP7 group (group CP+ LP), and control group (group C). The gastric antrum cross-sectional area (CSA) was measured by ultrasound in all the patients before induction of anesthesia, and facemask ventilation in pressure-controlled mode with suction pressure of 25 cmH 2O was applied, the patients in 4 groups were treated with different manipulations, and 3 min later the CSA of gastric antrum was measured again.The gastric antrum CSA before and after ventilation and the difference were recorded.The occurrence of gastric insufflation was examined by ultrasound after ventilation. Results:Compared with the baseline before ventilation, the CSA of gastric antrum was increased after ventilation in C, CP and LP groups ( P<0.01), and no significant change was found in the CSA after ventilation in CP+ LP group ( P>0.05). The difference of gastric antrum CSA was decreased in turn in C, CP, LP and CP+ LP groups ( P<0.05 or 0.01). The incidence of gastric insufflation were 53%, 30%, 12% and 0 in C, CP, LP and CP+ LP groups, respectively.Compared with group C, the incidence of gastric insufflation was significantly decreased in LP and CP+ LP groups ( P<0.05), and no significant change was found in group CP ( P>0.05). Compared with group CP, the incidence of gastric insufflation was significantly decreased in group CP+ LP ( P<0.05), and no significant change was found in group LP ( P>0.05). Conclusion:The combination of left PLP and cricoid pressure can effectively prevent gastric insufflation during positive pressure ventilation by facemask.

Effects of noninvasive positive pressure ventilation combined with positive expiratory pressure device on pulmonary function, inflammatory factors and short-term prognosis in older adult patients with acute exacerbations of chronic obstructive pulmonary disease / 中国基层医药

Objective:To investigate the effects of noninvasive positive pressure ventilation combined with positive expiratory pressure device on pulmonary function, inflammatory factors and short-term prognosis in older adult patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD), which provide objective evidence for clinical treatment and prognosis evaluation of this disease.Methods:Eighty-three older adult patients with AECOPD who received treatment in Taizhou Central Hospital, China between January 2016 and December 2018 were included in this study. They were randomly assigned to undergo either noninvasive positive pressure ventilation (control group, n = 38) or noninvasive positive pressure ventilation combined with positive expiratory pressure device (study group, n = 45) for 7 days. Pulmonary function, blood gas indexes, inflammatory factor levels and curative effect were compared between the two groups. Results:After treatment, partial pressure of oxygen (PaO 2) and oxygenation index (PaO 2/FiO 2) in each group were significantly increased, and partial pressure of carbon dioxide (PaCO 2) was significantly decreased, compared with before treatment (all P < 0.05). The degree of improvement in PaO 2, PaCO 2 and PaO 2/FiO 2 in the study group was greater than that in the control group ( t = 2.261, 6.854, 2.040, all P < 0.05). The ratio of forced expiratory volume in the first second (FEV 1) to forced vital capacity (FEV 1/FVC), the ratio of FEV1 to predicted value (FEV 1/Pre), and the maximum voluntary ventilation (MVV) per minute in each group were significantly increased compared with before treatment. After treatment, the degree of increase in FEV 1/FVC, FEV 1/Pre, and MVV in the study group was greater than that in the control group ( t = 2.442, 2.120, 2.944, all P < 0.05). After treatment, serum levels of inerleukin-8, tumor necrosis factor-α, and high-sensitivity C-reactive protein in each group were significantly decreased compared with before treatment (all P < 0.05). After treatment, the degree of decrease in serum levels of inerleukin-8, tumor necrosis factor-α, and high-sensitivity C-reactive protein in the study group was significantly greater than that in the control group ( t =7.978, 10.857, 8.543, all P < 0.05). Length of hospital stay, duration of antibiotic use, chronic obstructive pulmonary disease assessment test score and St. George's Respiratory Questionnaire score in the study group were (7.52 ± 1.38) days, (7.14 ± 1.38) days, (18.95 ± 4.76) points, (1.73 ± 4.21) points, respectively, which were significantly shorter/lower than those in the control group [(8.55 ± 1.47) days, (8.25 ± 1.45) days, (8.07 ± 5.81) points, (55.97 ± 5.28) points, t = -2.510, -2.722, -7.943, -10.351, all P < 0.05]. Conclusion:Noninvasive positive pressure ventilation combined with positive expiratory pressure device can effectively improve the pulmonary function of older adult patients with AECOPD, decrease the level of inflammatory factors, and improve short-term prognosis. This study is highly innovative and scientific and is of significance for clinical promotion.

Desafios para o desenvolvimento de ventiladores alternativos de baixo custo durante a pandemia de COVID-19 no Brasil / Challenges for the development of alternative low-cost ventilators during COVID-19 pandemic in Brazil

RESUMO A pandemia por COVID-19 tem deixado os gestores, os profissionais de saúde e a população preocupados com a potencial escassez de ventiladores pulmonares para suporte de pacientes graves. No Brasil, há diversas iniciativas com o intuito de produzir ventiladores alternativos para ajudar a suprir essa demanda. Para auxiliar as equipes que atuam nessas iniciativas, são expostos alguns conceitos básicos sobre fisiologia e mecânica respiratória, os termos comumente utilizados no contexto da ventilação mecânica, as fases do ciclo ventilatório, as diferenças entre disparo e ciclagem, os modos ventilatórios básicos e outros aspectos relevantes, como mecanismos de lesão pulmonar induzida pela ventilação mecânica, pacientes com drive respiratório, necessidade de umidificação de vias aéreas, risco de contaminação cruzada e disseminação de aerossóis. Após a fase de desenvolvimento de protótipo, são necessários testes pré-clínicos de bancada e em modelos animais, a fim de determinar a segurança e o desempenho dos equipamentos, seguindo requisitos técnicos mínimos exigidos. Então, é imprescindível passar pelo processo regulatório exigido pela Agência Nacional de Vigilância Sanitária (ANVISA). A empresa responsável pela fabricação do equipamento deve estar regularizada junto à ANVISA, que também deve ser notificada da condução dos testes clínicos em humanos, seguindo protocolo de pesquisa aprovado pelo Comitê de Ética em Pesquisa. O registro do ventilador junto à ANVISA deve ser acompanhado de um dossiê, composto por documentos e informações detalhadas neste artigo, que não tem o propósito de esgotar o assunto, mas de nortear os procedimentos necessários.

ABSTRACT The COVID-19 pandemic has brought concerns to managers, healthcare professionals, and the general population related to the potential mechanical ventilators' shortage for severely ill patients. In Brazil, there are several initiatives aimed at producing alternative ventilators to cover this gap. To assist the teams that work in these initiatives, we provide a discussion of some basic concepts on physiology and respiratory mechanics, commonly used mechanical ventilation terms, the differences between triggering and cycling, the basic ventilation modes and other relevant aspects, such as mechanisms of ventilator-induced lung injury, respiratory drive, airway heating and humidification, cross-contamination risks, and aerosol dissemination. After the prototype development phase, preclinical bench-tests and animal model trials are needed to determine the safety and performance of the ventilator, following the minimum technical requirements. Next, it is mandatory going through the regulatory procedures as required by the Brazilian Health Regulatory Agency (Agência Nacional de Vigilância Sanitária - ANVISA). The manufacturing company should be appropriately registered by ANVISA, which also must be notified about the conduction of clinical trials, following the research protocol approval by the Research Ethics Committee. The registration requisition of the ventilator with ANVISA should include a dossier containing the information described in this paper, which is not intended to cover all related matters but to provide guidance on the required procedures.

Recomendaciones en los laboratorios de sueño y para el uso de dispositivos de presión positiva durante la pandemia por COVID-19 / Recommendations in sleep lab and for the use of positive pressure devices during the pandemic of COVID-19

La enfermedad por coronavirus 2019 o COVID-19 se transmite principalmente a través de gotas respiratorias, contacto cercano no protegido y procedimientos generadores de aerosoles (1). Las pruebas realizadas en un laboratorio de sueño y la terapia con presión positiva, como la CPAP o la BPAP, pueden aumentar el riesgo de exposición de transmisión de COVID-19 al personal médico y a los pacientes. Las decisiones basadas en la evidencia son el estándar ideal; sin embargo, esta evidencia va apareciendo poco a poco, a un ritmo más lento que la emergencia de salud pública que estamos viviendo; por tanto, por el momento debemos basar nuestras decisiones en la experiencia, en documentos de consenso, cuando estén disponibles, y en el juicio clínico, cuando no exista evidencia. Nuestro objetivo es proporcionar unas recomendaciones, teniendo como marco de referencia las dictadas por organismos nacionales e internacionales, como la Asociación Colombiana de Medicina del Sueño, la Academia Americana de Medicina del Sueño, la Academia Mexicana de Medicina del Dormir y otras publicaciones en revistas indexadas (2,3).

The coronavirus disease 2019 or COVID-19 is transmitted primarily through respiratory drops, unprotected close contact, and aerosol-generating procedures (1). Tests performed in a sleep laboratory and positive pressure therapy such as CPAP or BPAP, may increase the risk of exposure of transmission of COVID-19 to clinicians and patients. Evidence-based making decisions are the ideal standard, however, this evidence appears little by little, at a slower rate than the public health emergency that we are experiencing; therefore, for the moment, our decisions must be based on our experience, on consensus documents, when they are available, and clinical judgment when there is no evidence. Our objective is to give recommendations, taking as a reference framework those issued by national and international organizations, such as Colombian Asociation of Sleep Medicine, the American Academy of Sleep Medicine, the Mexican Academy of Sleep Medicine, and other publications in indexed journals.

Impact of lung expansion therapy using positive end-expiratory pressure in mechanically ventilated patients submitted to coronary artery bypass grafting

Abstract Objective: To evaluate the impact of different levels of positive end-expiratory pressure (PEEP) on gas exchange in patients undergoing coronary artery bypass grafting (CABG). Methods: A randomized clinical trial was conducted with patients undergoing CABG surgery. Patients were randomized into three groups: Group 10, PEEP of 10 cmH2O; Group 12, PEEP of 12 cmH2O; and Group 15, PEEP of 15 cmH2O. After the randomization, all patients underwent gas analysis at three moments: (1) before lung expansion therapy (LET); (2) 30 minutes after LET; and (3) one hour after extubation. Results: Sixty-six patients were studied, of which 61.7% were men, with mean age of 64 ± 8.9 years. Patients allocated to Group 15 showed a significant improvement in gas exchange comparing pre- and post-expansion values (239±21 vs. 301±19, P<0,001) and the increase was maintained after extubation (278±26). Despite the use of high levels of PEEP, no significant hemodynamic change was evidenced. Conclusion: It is concluded that high levels of PEEP (15 cmH2O) are beneficial for the improvement of gas exchange in patients undergoing CABG.

Efeitos agudos da hiperinsuflação com o ventilador com aumento do tempo inspiratório sobre a mecânica respiratória: ensaio clínico cruzado randomizado / Acute effects of ventilator hyperinflation with increased inspiratory time on respiratory mechanics: randomized crossover clinical trial

RESUMO Objetivo: Avaliar os efeitos da hiperinsuflação com o ventilador sobre a mecânica respiratória. Métodos: Foi realizado ensaio clínico cruzado randomizado com 38 pacientes ventilados mecanicamente com infecção pulmonar. A ordem da hiperinsuflação ou controle (sem alterações nos parâmetros) foi randomizada. A hiperinsuflação foi realizada por 5 minutos no modo ventilação com pressão controlada, com aumentos progressivos de 5cmH2O até atingir pressão máxima de 35cmH2O, mantendo-se a pressão positiva expiratória final. Após atingir 35cmH2O, o tempo inspiratório e a frequência respiratória foram ajustados para que os fluxos inspiratório e expiratório atingissem a linha de base, respectivamente. As medidas de complacência estática, resistências total e de vias aéreas e pico de fluxo expiratório foram avaliadas antes, imediatamente após a manobra e após aspiração. Foi utilizada a análise de variância two-way para medidas repetidas com pós-teste de Tukey, considerando significativo p < 0,05. Resultados: A hiperinsuflação com o ventilador aumentou a complacência estática, mantendo-se após aspiração (46,2 ± 14,8 versus 52,0 ± 14,9 versus 52,3 ± 16,0mL/cmH2O; p < 0,001). Houve aumento transitório da resistência de vias aéreas (6,6 ± 3,6 versus 8,0 ± 5,5 versus 6,6 ± 3,5cmH2O/L.s-1; p < 0,001) e redução transitória do pico de fluxo expiratório (32,0 ± 16,0 versus 29,8 ± 14,8 versus 32,1 ± 15,3Lpm; p < 0,05) imediatamente após a manobra, com redução após aspiração traqueal. Não foram observadas modificações no controle e nem alterações hemodinâmicas. Conclusão: A hiperinsuflação com o ventilador promoveu aumento da complacência associado ao aumento transitório da resistência de vias aéreas e do pico de fluxo expiratório, com redução após aspiração.

ABSTRACT Objective: To evaluate the effects of ventilator hyperinflation on respiratory mechanics. Methods: A randomized crossover clinical trial was conducted with 38 mechanically ventilated patients with pulmonary infection. The order of the hyperinflation and control (without changes in the parameters) conditions was randomized. Hyperinflation was performed for 5 minutes in pressure-controlled ventilation mode, with progressive increases of 5cmH2O until a maximum pressure of 35cmH2O was reached, maintaining positive end expiratory pressure. After 35cmH2O was reached, the inspiratory time and respiratory rate were adjusted so that the inspiratory and expiratory flows reached baseline levels. Measurements of static compliance, total resistance and airway resistance, and peak expiratory flow were evaluated before the technique, immediately after the technique and after aspiration. Two-way analysis of variance for repeated measures was used with Tukey's post hoc test, and p < 0.05 was considered significant. Results: Ventilator hyperinflation increased static compliance, which remained at the same level after aspiration (46.2 ± 14.8 versus 52.0 ± 14.9 versus 52.3 ± 16.0mL/cmH2O; p < 0.001). There was a transient increase in airway resistance (6.6 ± 3.6 versus 8.0 ± 5.5 versus 6.6 ± 3.5cmH2O/Ls-1; p < 0.001) and a transient reduction in peak expiratory flow (32.0 ± 16.0 versus 29.8 ± 14.8 versus 32.1 ± 15.3Lpm; p <0.05) immediately after the technique; these values returned to pretechnique levels after tracheal aspiration. There were no changes in the control condition, nor were hemodynamic alterations observed. Conclusion: Ventilator hyperinflation promoted increased compliance associated with a transient increase in airway resistance and peak expiratory flow, with reduction after aspiration.

Fluid balance in pediatric patients in prone position: a pragmatic study

SUMMARY OBJECTIVE: To verify the association between prone position, increased diuresis, and decreased cumulative fluid balance in critically ill pediatric patients who underwent mechanical ventilation (MV) for pulmonary causes and describe adverse events related to the use of the position. METHODS: This is a retrospective observational study. Patients aged between 1 month and 12 years who underwent MV for pulmonary causes, between January 2013 and December 2015, were selected and divided between those who were put on prone position (PG) and those who were not (CG) during the hospitalization at the Pediatric Intensive Care Unit (PICU). Data were analyzed longitudinally from D1 to D4. RESULTS: A total of 77 patients (PG = 37 and CG = 40) were analyzed. The general characteristics of both groups were similar. In the comparison between the groups, there was no increase in diuresis or decrease in cumulative fluid balance in the prone group. In the longitudinal analysis of D1 to D4, we saw that the PG presented higher diuresis (p = 0.034) and a lower cumulative fluid balance (p = 0.001) in D2. Regarding the use of diuretics, there was greater use of furosemide (P <0.001) and spironolactone (P = 0.04) in the PG. There was no increase in adverse events during the use of the prone position. CONCLUSION: The prone position was not associated with increased diuresis or decreased cumulative fluid balance in critically ill pediatric patients who underwent to MV for pulmonary causes.

RESUMO OBJETIVO: Verificar a associação entre posição prona, aumento da diurese e diminuição do balanço hídrico em pacientes pediátricos criticamente enfermos e submetidos à ventilação mecânica (VM) por causa pulmonar, além de descrever eventuais intercorrências relacionadas à aplicação dessa posição. MÉTODOS: Estudo observacional retrospectivo. Pacientes submetidos à VM por causa pulmonar, com idade entre 1 mês e 12 anos no período entre janeiro de 2013 e dezembro de 2015, foram selecionados e divididos entre os que receberam posição prona (GP) e os que não receberam (GC) durante a internação na Unidade de Terapia Intensiva Pediátrica (Utip). Os dados foram analisados longitudinalmente de D1 a D4. RESULTADOS: Foram analisados77 pacientes (GP=37 e GC=40). Em termos de características gerais, os grupos foram semelhantes entre si. Na comparação entre os grupos, não houve aumento da diurese ou diminuição do balanço hídrico cumulativo no grupo prona. Na análise longitudinal de D1 a D4, evidenciou-se que o GP apresentou maior diurese (p=0,034) e menor balanço hídrico cumulativo (p = 0,001) no D2. Com relação ao uso de diuréticos, houve maior uso de furosemida (P<0,001) e de espironolactona (P=0,04) no GP. Não houve aumento de eventos adversos durante a utilização da posição prona. CONCLUSÃO: A posição prona não demonstrou associação com aumento da diurese ou diminuição de balanço hídrico cumulativo em pacientes críticos pediátricos submetidos à VM por causa pulmonar.

Effect of NIPPV in the treatment of AECOPD complicated with type Ⅱ respiratory failure and its influence on blood gas index / 中国基层医药

Objective@#To investigate the effect of noninvasive positive pressure ventilation(NIPPV) in the treatment of patients with acute exacerbation of chronic obstructive pulmonary disease(AECOPD) complicated with type Ⅱ respiratory failure and its influence on blood gas index.@*Methods@#From August 2014 to December 2016, the clinical data of 79 patients with AECOPD complicated with type Ⅱ respiratory failure in the Central Hospital of Shanxi Coal were retrospectively analyzed.The patients were divided into two groups according to different treatment methods.Thirty-five patients in the control group were treated with conventional therapy, 44 patients in the observation group were treated with conventional NIPPV.The blood gas index, nutritional index, plasma N-terminal brain natriuretic peptide precursor(NT-proBNP), lactate(Lac) and the changes of procalcitonin (PCT), soluble myeloid cell trigger receptor-1(sTREM-1) level were compared between the two groups.@*Results@#There were no statistically significant differences in respiratory frequency, blood gas index and APACHE Ⅱ score between the two groups before treatment(P=0.282, 0.177, 0.485, 0.472, 0.485). The levels of pH (7.41±0.07) and PaO2[(82.30±6.99)mmHg]in the observation group were higher than those in the control group(t=9.357, 5.328, P=0.000, 0.000). The respiratory frequency[(20.02±2.15)times/min], PaCO2[(52.36±5.15)mmHg]and APACHE Ⅱ score[(18.20±1.01)points]in the observation group were lower than those in the control group(t=7.782, 10.608, 9.360, P=0.000, 0.000, 0.000). There were no statistically significant differences between the two groups in the levels of nutritional indicators before treatment(t=0.027, 0.039, 0.068, P=0.488, 0.485, 0.473). After treatment, the serum total protein level in the observation group was higher than that in the control group, but the levels of serum albumin and hemoglobin had no statistically significant differences compared with those in the control group(t=3.606, 1.659, 0.034, P=0.000, 0.051, 0.486). There were no statistically significant differences in the levels of Lac, NT-proBNP, inflammatory factors between the two groups before treatment(P=0.465, 0.477, 0.451, 0.493). The levels of Lac[(1.57±0.55)mmol/L], NT-proBNP[(130.25±42.36)ng/L], PCT[(0.16 ±0.09)g/L], sTREM-1[(66.36±12.87)ng/L]in the observation group were lower than those in the control group(t=7.662, 2.248, 4.030, 2.709, P=0.000, 0.014, 0.000, 0.004). After treatment, the respiratory rate, blood gas index and APACHE Ⅱ score of the two groups were improved compared with those of the control group(all P<0.05). The respiratory rate per minute, pH, PaO2, PaCO2 and APACHE Ⅱ scores in the observation group were better than those in the control group(all P<0.05). The levels of serum total protein, hemoglobin and Lac, NT-proBNP, inflammatory factors in the two groups were lower than those before treatment, and the levels of serum total protein and Lac, NT-proBNP, PCT, sTREM-1 in the observation group were higher than those in the control group(all P<0.05). The serum albumin level in the control group after treatment was lower than that before treatment, and there was no statistically significant difference between the two groups after treatment(P>0.05).@*Conclusion@#NIPPV in the treatment of AECOPD complicated with type Ⅱ respiratory failure can effectively improve the blood gas status and nutritional status of patients, and reduce the body Lac and NT-proBNP levels.

Optimal PEEP for volume-controlled ventilation in patients undergoing surgery with general anesthesia: pulmonary electrical impedance tomography monitoring / 中华麻醉学杂志

Objective To determine the optimal positive end-expiratory pressure (PEEP) for volume-controlled ventilation using pulmonary electrical impedance tomography in the patients undergoing surgery with general anesthesia.Methods Fifty patients of both sexes,aged 18-64 yr,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,with body mass index of 18.5-28.0 kg/m2,scheduled for surgery for ureteral calculi under general anesthesia,were enrolled in this study.The patients were tracheally intubated after anesthesia induction and mechanically ventilated in volume-controlled mode,with tidal volume 6 ml/kg,mean arterial pressure was recorded at 3 min of ventilation and served as the baseline value,and then PEEP was increased with an increment of 3 cmH2O every 3 min until PEEP reached 15 cmH2 O.The percentage of dorsal pulmonary ventilation and peak airway pressure were recorded at 3 min of ventilation with different PEEPs.When the decrease in mean arterial pressure was more than 20％ of the baseline value during ventilation,deoxyepinephrine 0.1 mg was injected intravenously,and the consumption of deoxyepinephrine was recorded within 3 min of ventilation with different PEEPs.Results Peak airway pressure was gradually increased with the increase of PEEP (P＜0.05),the percentage of dorsal pulmonary ventilation was gradually increased when PEEP was 6 cmH2O (P＜ 0.05),and the consumption of deoxyepinephrine was gradually increased when PEEP was 15 cmH2O (P＜0.05).Conclusion The optimal PEEP is 12 cmH2O during volume-controlled ventilation with tidal volume of 6 ml/kg in the patients undergoing surgery with general anesthesia.

Effect of PEEP on lung atelectasis in pediatric patients without high risk factors: evaluation using lung ultrasound / 中华麻醉学杂志

Objective To evaluate the effect of positive end-expiratory pressure (PEEP) on lung atelectasis using lung ultrasound ( LUS) in the pediatric patients without high risk factors. Methods One hundred American Society of Anesthesiologists physical statusⅠor Ⅱ patients of both sexes, aged 1-6 yr, with body mass index in the normal range, scheduled for elective non-abdominal surgery, were divided into no PEEP group (group C, n=50) and PEEP group (group P, n=50) using a random number table meth-od. The animals were mechanically ventilated in volume-controlled mode after intravenously injecting propo-fol, with PEEP 5 cmH2 O, tidal volume 8 ml/kg, inspiratory/expiratory ratio 1 : 2, respiratory rate 20-25 breaths/min in group P. In group C, the animals received no PEEP, and the other treatments were similar to those previously described in group P . Lung ultrasound was carried out after anesthesia induction and at the end of surgery. The severity and development of lung atelectasis were recorded. Results Compared with group C, the severity of lung atelectasis was significantly reduced after anesthesia induction and at the end of surgery, and the incidence of lung atelectasis was decreased in group P ( P＜0. 05) . Conclusion Early application of PEEP 5 cmH2 O can reduce the occurrence of atelectasis for the pediatric patients with-out high risk factors for atelectasis.