Cambios en Mecánica Respiratoria en Usuarios Pediátricos en Ventilación Mecánica Post Cirugía de Cardiopatía Congénita Sometidos a Kinesiología Respiratoria versus Succión Endotraqueal. Revisión Estructurada / Changes in Respiratory Mechanics in Pediatric Users on Mechanical Ventilation Post Congenital Heart Disease Surgery Undergoing Respiratory Kinesiology versus Endotracheal Suction. Structured Review

Introducción. Las cardiopatías congénitas (CC) en Chile corresponden a la segunda causa de muerte en menores de 1 año, requiriendo cirugías paliativas y/o correctivas el 65% de estas. En el post operatorio frecuentemente se utiliza ventilación mecánica invasiva (VM) y succión endotraqueal (SET) para remover secreciones. Sin embargo, la kinesiología respiratoria (KTR) ha mostrado mejoras significativas en la distensibilidad toracopulmonar (Cest) y resistencia de vía aérea (Rva) en otros grupos de usuarios pediátricos y adultos en VM. Objetivo. Comparar los cambios en la Cest y Rva en usuarios pediátricos en VM post cirugía de cardiopatía congénita (CCC) sometidos a KTR versus SET exclusiva. Métodos. Revisión sistemática de estudios publicados en bases de datos PUBMED, PeDro, Scielo y Google Scholar que comparan el uso de KTR ó SET sobre los cambios en mecánica ventilatoria en usuarios pediátricos en VM post cirugía de cardiopatía congénita, limitados a inglés, español y portugués, excluyendo a sujetos con traqueostomía o con oxigenación por membrana extracorpórea. Se utilizó guía PRISMA para la selección de artículos. Se revisaron 397 artículos y se seleccionó 1 artículo extra de los artículos sugeridos. Se eliminó 1 artículo por duplicidad. Por títulos y resúmenes se seleccionaron 2 artículos, los cuales al leer el texto completo fueron retirados debido a que la población no correspondía a cardiópatas. Resultados. El final de artículos seleccionados fue de 0 artículos, debido a lo cual se removió el operador Booleano "NOT", y se removió la población de cardiopatías. De este modo quedaron 2 artículos seleccionados para la revisión cualitativa final donde se compara KTR versus SET, y KTR en kinesiólogos especialistas y no especialistas, mostrando ambos aumento en la Cest y disminución de la Rva a favor de la KTR, hasta los 30 minutos post intervención. Conclusiones. No se encontraron artículos que demuestren cambios en Cest y Rva con el uso de KTR + SET versus SET exclusiva, en usuarios pediátricos ventilados posterior a CCC. Con la remoción de filtros seleccionamos 2 artículos que demuestran aumento de Cest y disminución de Rva en sujetos pediátricos en VM, uno comparando con SET, y por grupos de especialistas y no especialistas en respiratorio. Se sugieren estudios primarios para evaluar los efectos de esta intervención en esta población.

Introduction. Congenital heart diseases (CHD) are the second general cause for children death under 1 year. In Chile, approximately 65% CHD need surgery, could was palliative or corrective. In the postoperative period, invasive mechanical ventilation (MV) is frequently used as a life support method, but it is associated with complications. Tracheal suction (SET) is regularly used to remove secretions; however, respiratory chest physiotherapy (KTR) has shown significant improvements in thoraco-pulmonary compliance and airway resistance in other groups of pediatrics and adult's users in MV. Objetive. to compare changes in thoraco-pulmonary compliance and airway resistance in pediatric subjects under mechanical ventilation after congenital heart disease surgery comparing chest physiotherapy and exclusive tracheal suction. Methods. systematic review of studies published in PUBMED, PeDro, Scielo and Google Scholar databases who compares KTR or SET use on changes in ventilatory mechanics in pediatric users under MV after congenital heart disease surgery, limited to English, Spanish and Portuguese languages, excluding user with tracheostomy or extracorporeal membrane of oxygenation. It was use the PRISMA guide to articles selection. A search was carried out, with a total of 397 articles reviewed (English: PubMed = 3, PeDro = 8, Scholar = 383; Spanish: Scholar = 3, Scielo = 0; and Portuguese: Scielo = 0). One extra article was selected from the suggested articles, and 1 article was eliminated due to duplication. By titles and abstracts, 2 articles were selected, but the population did not correspond to heart disease. Results. the final selected articles were 0 articles. By this reason, it were removed: Boolean operator "NOT", and congenital heart disease population. Thus, 2 articles were selected for the final qualitative review where it was compares KTR versus SET, and KTR by specialist and non-specialist. Both articles shown improvement in compliance and resistance until 30 minutes post intervention. The CC population was in a 40 to 60% range in both studies. Conclusions. it was no found articles that demonstrate changes in compliance and resistance in the airway with the use of KTR + SET versus exclusive SET in pediatric users after CCC connected to MV. After filter remotion, we found 2 studies shown improves in increase compliance and reduce resistance in pediatric user in MV, ones comparing with SET, and the other one comparing between specialists in respiratory pediatric physiotherapy and not specialists. It suggests to made primary clinical studies about this intervention in CC population.

Estimación de Distensibilidad Dinámica Toraco-pulmonar en Modelos Neonatales de Ventilación Mecánica de Alta Frecuencia / Estimation of dynamic thoracopulmonary compliance in neonatal high-frequency mechanical ventilation models

Introducción. La ventilación de alta frecuencia (VAF) es utilizada en pacientes graves neonatales con un uso cercano al 10% del total de usuarios en ventilación mecánica (VM). Actualmente estos equipos miden volumen corriente de manera precisa, continua y rutinaria, sin embargo no hay estimaciones del comportamiento mecánico del sistema respiratorio del usuario, como lo es la distensibilidad toracopulmonar, durante el ciclo ventilatorio que sean reportadas por las pantallas de los equipos. Objetivo. Estimar distensibilidad dinámica toracopulmonar en modelos neonatales de VAF. Métodos. Estudio cuantitativo, observacional, descriptivo, y "wench work", donde se midió distensibilidad en VM convencional y volumen corriente (Vt) en VAF con equipo Acutronics Fabian® por 4 evaluadores independientes, en 5 tipos de pulmón de ensayo y bajo diferentes escenarios de parámetros de VAF con ajustes de presión media de la vía aérea (PMVA), amplitud, frecuencia respiratoria, tiempo inspiratorio, volumen garantizado, y tipo de circuito. Mediante suavización de regresiones locales por estimación mínima cuadrática (LOWESS) y análisis de regresión multivariada se obtuvieron los valores asociados a distensibilidad, con los que se construyeron ecuaciones de estimación de distensibilidad en VAF. Resultados. Se realizaron en total 46080 mediciones, con correlación intra e interevaluador > 0.99. La distensibilidad mediana (percentil 25; 75) de los 5 modelos pulmonares fue de 0.455 (0.3; 0.98). Se asociaron a distensibilidad, mediante modelos de regresión lineal múltiple de manera significativa, todas las variables evaluadas, salvo PMVA. Se establecieron asociaciones multivariantes crudas (R2=.311), de distensibilidad predicha por LOWESS (R2=.744) y distensibilidad predicha y variables independientes predichas por regresión lineal simple (R2=.973). Conclusiones. La distensibilidad en VAF esta determinada en pulmones de ensayos por los parámetros programados de: tipo de circuito, uso de volumen garantizado, tiempo inspiratorio, frecuencia respiratoria y amplitud, además del Vt medido. Se reporta ecuación explicativa de distensibilidad en VAF.

Background. Background: High frequency mechanical ventilation (HFV) is used in severe neonatal subjects nearly 10% of total mechanically ventilated (MV) users. Currently, this MV's mode allow to measure tidal volumen in an accurately, continuous and routinarie way in HFV, however there are non estimation to assess mechanical behavior of respiratory system during ventilatory cycle, like thoraco-pulmonary compliance, who be report in the equipment display. Objetive. To estimate thoraco-pulmonary compliance in artificial neonatal lung models in HFV. Methods. Quantitative, observational, descriptive, and wench work study, where distensibility was measured in conventional MV and tidal volume (TV) in HFV with Acutronics Fabian® equipment by 4 independent evaluators, in 5 types of test lung and under different scenarios of HFV parameters with adjustments of mean airway pressure (MAP), amplitude, respiratory rate, inspiratory time, guaranteed volume, and type of circuit. By smoothing local regressions by least quadratic estimation (LOWESS) and multivariate regression analysis, the values associated with distensibility were obtained, with this measures, equations for estimating compliance in VAF were constructed. Results. A total of 46080 measurements were made, with intra and inter-evaluator correlation coefficent > 0.99. The median compliance (25th percentile; 75) of the 5 lung models was 0.455 (0.3; 0.98). All variables evaluated, except MAP, were associated with compliance, by means of multiple linear regression models. Crude multivariate associations (R2 = .311), predicted compliance by LOWESS (R2 = .744) and predicted compliance and independent variables predicted by simple linear regression (R2 = .973) were established to estimate thoraco-pulmonary compliance. Conclusions. Compliance in VAF is determined in test lungs by the programmed parameters of: type of circuit, use of guaranteed volume, inspiratory time, respiratory frequency and amplitude, in addition to the measured Vt. An explanatory equation for distensibility in VAF is reported.

Análise comparativa da complacência do sistema respiratório em três diferentes posições no leito (lateral, sentada e dorsal) em pacientes submetidos à ventilação mecânica invasiva prolongada / Comparative analysis of respiratory systems compliance in three different positioning (lateral, dorsal and sitting) in patients in prolonged invasive mechanical ventilation

OBJETIVOS: A realização deste estudo se justifica pelo fato que na prática clinica ocorrem constantes mudanças de decúbito do paciente no leito durante a hospitalização na terapia intensiva, sendo que necessita melhor entendimento sobre possíveis efeitos adversos principalmente sobre as condições do sistema respiratório que tais mudanças podem ocasionar. O objetivo deste estudo foi avaliar se o posicionamento do paciente no leito pode interferir na complacência pulmonar. MÉTODOS: Todos os pacientes incluídos neste estudo estavam em ventilação mecânica, e foram sedados e curarizados. Verificou-se a complacência do sistema respiratório de todos os pacientes em três diferentes posicionamentos: decúbito lateral (DL), decúbito dorsal (DD) e sentado (PS), para tanto, após a manobra de recrutamento alveolar os pacientes ficavam no posicionamento definido por 2 horas e nos últimos 5 min os dados eram colhidos do mostrador do ventilador mecânico. RESULTADOS: Vinte e oito pacientes foram prospectivamente analisados, Os valores de complacência do sistema respiratório no DL foram 37,07 ± 12,9 no DD 39,2 ± 10,5 e na PS 43,4 ± 9,6 mL/cmH2O. Houve diferença estatisticamente significativa quando a PS e a DD foram comparadas com a DL para complacência o sistema respiratório (p = 0.0052) e volume corrente (p < 0.001). Houve correlação negativa entre os valores médios de pressão expiratória final positiva e complacência do sistema respiratório (r = 0,59, p = 0,002). Para o DL a FIO2 foi 0,6, para o DD e posição sentada foi 0,5. (p = 0,049). CONCLUSÕES: O posicionamento dos pacientes no leito, em ventilação mecânica invasiva, ocasiona variação na complacência do sistema respiratório, volume corrente e saturação arterial de oxigênio. Na posição sentada a complacência do sistema respiratório é maior quando comparada aos decúbitos dorsal e lateral.

OBJECTIVES: This study is justified by the fact that in clinical practice, changes occur in patient's positioning in the bed during hospitalization in intensive care unity, it's necessary better understanding about possible adverse effects that such changes might cause mainly on the respiratory system condition. The objective this study was to evaluate if the patients positioning in bed can to alter the pulmonary complacency. METHODS: All included patients were submitted to mechanical ventilation and were sedated and curarized respiratory system compliance was assessed in three different positioning: lateral, dorsal and sitting. After an alveolar recruitment maneuver, patients were placed to a position throughout two hours, and in the last five minutes the data was collected from the mechanical ventilator display. RESULTS: twenty eight patients were prospectively assessed. Values of respiratory system compliance in the lateral position were 37,07 ± 12,9 in the dorsal were 39,2 ± 10,5 and in the sitting 43,4 ± 9,6 mL/cmH2O. There were a statistical difference when we compared to the sitting and dorsal with lateral positioning for respiratory system compliance (p = 0.0052) and tidal volume (p < 0.001). There was a negative correlation between mean values of positive end expiratory pressure a respiratory system compliance (r = 0.59, p = 0.002). The FIO2 administered was 0.6 for the lateral positioning and 0.5 for the dorsal and sitting positioning (p = 0.049). CONCLUSIONS: That body positioning in patients restrained to a bed and submitted to invasive mechanical ventilation leads to pulmonary compliance, tidal volume and SpO2 oscillations. In the sitting position the pulmonary compliance is higher than in others positions.

Mecânica pulmonar de pacientes em suporte ventilatório na unidade de terapia intensiva. Conceitos e monitorização / Concepts and monitoring of pulmonary mechanic in patients under ventilatory support in intensive care unit

JUSTIFICATIVA E OBJETIVOS: Em ventilação mecânica invasiva e não-invasiva, o conhecimento da fisiologia da mecânica respiratória, é imprescindível para tomada de decisões e no manuseio eficiente dos ventiladores modernos. A monitorização dos parâmetros da mecânica pulmonar é recomendada nos trabalhos de revisão e de pesquisas clínicas. O objetivo deste estudo foi rever os conceitos de mecânica pulmonar e os métodos utilizados para obtenção de medidas à beira do leito, enfatizando três parâmetros: resistência, complacência e PEEP intrínseca. MÉTODO: Foi realizada revisão bibliográfica através dos bancos de dados LILACS, MedLine e PubMed, no período de 1996 a 2006. RESULTADOS: Esta revisão abordou os parâmetros de resistência, complacência pulmonar e PEEP intrínseca como fundamentais na compreensão da insuficiência respiratória aguda e suporte ventilatório mecânico, principalmente na doença pulmonar obstrutiva crônica (DPOC) e na síndrome da angústia respiratória aguda (SARA). CONCLUSÕES: A monitorização da mecânica pulmonar em pacientes sob ventilação mecânica em unidade de terapia intensiva (UTI) pode fornecer dados relevantes e deve ser implementada de forma sistemática e racional.

BACKGROUND AND OBJECTIVES: In mechanical ventilation, invasive and noninvasive, the knowledge of respiratory mechanic physiology is indispensable to take decisions and into the efficient management of modern ventilators. Monitoring of pulmonary mechanic parameters is been recommended from all the review works and clinical research. The objective of this study was review concepts of pulmonary mechanic and the methods used to obtain measures in the bed side, preparing a rational sequence to obtain this data. METHODS: It was obtained bibliographic review through data bank LILACS, MedLine and PubMed, from the last ten years. RESULTS: This review approaches parameters of resistance, pulmonary compliance and intrinsic PEEP as primordial into comprehension of acute respiratory failure and mechanic ventilatory support, mainly in acute respiratory distress syndrome (ARDS) and in chronic obstructive pulmonary disease (COPD). CONCLUSIONS: Monitoring pulmonary mechanics in patients under mechanical ventilation in intensive care units gives relevant informations and should be implemented in a rational and systematic way.

The Effects of 6% Hydroxyethyl Starch (HES) 130/0.4 and 6% HES 200/0.5 on Tissue Oxygenation and Postoperative Bleeding in Patients undergoing Off-pump Coronary Artery Bypass Surgery / 대한마취과학회지

BACKGROUND: Hydroxyethyl starch (HES) effectively restores plasma volume and thereby enhances microcirculation and tissue oxygenation at the expense of coagulation impairment. These effects are related to molecular weight, substitution and C2:C6 ratio. But, most of the studies regarding coagulation impairment in cardiac surgeries were performed in patients undergoing cardiopulmonary bypass which significantly causes coagulation derangements. Therefore, we have evaluated the effects of 2 different HES solutions on tissue oxygenation and postoperative bleeding in patients undergoing off-pump coronary artery bypass surgery (OPCAB). METHODS: Forty four patients were prospectively enrolled. After the induction of anesthesia, either HES 130/0.4 (V group) or 200/0.5 (H group) were infused for fluid therapy to maintain predetermined urine output, cardiac index and filling pressure up to 16 h after the surgery. Tissue oxygenation profiles and respiratory parameters were recorded after induction of anesthesia, completion of distal anastomosis and sternum closure, upon admission at intensive care unit, and 4 h thereafter. The amounts of chest tube drainage, transfusion and fluid balance were measured up to 16 h after the surgery. RESULTS: Patients' demographic data were similar between the groups. Tissue oxygenation profiles, respiratory parameters, hemodynamics, and time to extubate were not different between the groups. However, chest tube drainage and transfusion requirements were significantly less in the V group. CONCLUSIONS: In OPCAB, 6% HES 130/0.4 causes less postoperative bleeding and transfusion requirement and has a comparable efficacy on hemodynamic stability, pulmonary function and tissue oxygenation when compared to 6% HES 200/0.5.

Assisted Cough and Pulmonary Compliance in Patients with Duchenne Muscular Dystrophy

The aim of this study was to investigate the factors affecting cough ability, and to compare the assisted cough methods in patients with Duchenne muscular dystrophy (DMD). A total seventy-one male patients with DMD were included in the study. The vital capacity (VC) and maximum insufflation capacity (MIC) were measured. The unassisted peak cough flow (UPCF) and three different techniques of assisted peak cough flow were evaluated. UPCF measurements were possible for all 71 subjects. But when performing the three different assisted cough techniques, peak cough flows (PCFs) could be obtained from only 51 subjects. The mean value of MICs (1801+/-780cc) was higher than that of VCs (1502+/-765cc) (p< 0.01). All three assisted cough methods showed a significantly higher value than the unassisted method (F=80.92, p< 0.01). The manual assisted PCF under MIC (MPCFmic) significantly exceeded those produced by manual assisted PCF (MPCF) or PCF under MIC (PCFmic). The positive correlation between the MIC, VC difference (MIC-VC), and the difference between PCFmic and UPCF (PCFmic-UPCF) was seen (r= 0.572, p< 0.01). The preservation of pulmonary compliance is important for the development of an effective cough as well as assisting the compression and expulsive phases. Thus, the clinical importance of the inspiratory phase and pulmonary compliance in assisting a cough should be emphasized.

Analysis of Pulmonary Mechanics and the Factors for Coughing in Duchenne Muscular Dystrophy

OBJECTIVE: To investigate the pathologic pulmonary mechanics and analyze the factors affecting cough ability in patients with Duchenne muscular dystrophy (DMD). METHOD: Thirty-one patients with DMD were investigated. The vital capacity (VC), maximum insufflation capacity (MIC), maximal inspiratory (MIP), and expiratory pressure (MEP) were measured. Unassisted peak cough flow (UPCF) and assisted PCF at three different conditions were evaluated. RESULTS: The mean value of MICs (1, 873 +/- 644 cc) was higher than that of VCs (1, 509 +/- 640 cc). MIP and MEP were 48.8 +/- 21.4% and 29.5 +/- 19.5% of predicted normal value respectively. MIP was correlated with UPCFs as well as MEP. All of three assisted cough methods showed significantly higher value than unassisted method (p<0.01). The manual assisted PCFs at MIC significantly exceeded those produced by manual assisted or PCFs at MIC. The positive correlation between the MIC-VC difference and PCF at MIC-UPCF difference was seen (p<0.01). CONCLUSION: Inspiratory muscle strength and the preservation of pulmonary compliance is important for the development of effective cough as well as expiratory muscle power. Thus, the clinical implication of the inspiratory phase in assisting a cough should be emphasized.