Analysis of different levels of positive end-expiratory pressure during lung retrieval for transplantation: an experimental study

Atelectasis and inadequate oxygenation in lung donors is a common problem during the retrieval of these organs. Nevertheless, the use of high positive end-expiratory pressure (PEEP) is not habitual during procedures of lung retrieval. Twenty-one Sprague-Dawley male consanguineous rats were used in the study. The animals were divided into 3 groups according to the level of PEEP used: low (2 cmH2O), moderate (5 cmH2O), and high (10 cmH2O). Animals were ventilated with a tidal volume of 6 mL/kg. Before lung removal, the lungs were inspected for the presence of atelectasis. When atelectasis was detected, alveolar recruitment maneuvers were performed. Blood gasometric analysis was performed immediately. Finally, the lungs were retrieved, weighed, and submitted to histological analysis. The animals submitted to higher PEEP showed higher levels of oxygenation with the same tidal volumes PO2=262.14 (PEEP 2), 382.4 (PEEP 5), and 477.0 (PEEP 10). The occurrence of atelectasis was rare in animals with a PEEP of 10 cmH2O, which therefore required less frequent recruitment maneuvers (need for recruitment: PEEP 2=100%, PEEP 5 =100%, and PEEP 10=14.3%). There was no change in hemodynamic stability, occurrence of pulmonary edema, or other histological injuries with the use of high PEEP. The use of high PEEP (10 cmH2O) was feasible and probably a beneficial strategy for the prevention of atelectasis and the optimization of oxygenation during lung retrieval. Clinical studies should be performed to confirm this hypothesis.

Atelectasias em pediatria: mecanismos, diagnóstico e tratamento: [revisão] / Atelectasis: mechanisms, diagnosis and treatment in the pediatric patient: [review]

OBJETIVO: Realizar uma revisão da literatura sobre os mecanismos, diagnóstico e tratamento das atelectasias pulmonares em pediatria. MÉTODOS:Efetuou-se uma pesquisa nos bancos de dados eletrônicos Medline e Scielo com os critérios de inclusão: artigos publicados entre os anos de 1960 e 2007, que abordassem a etiologia, fisiopatologia, conseqüências funcionais, avaliação, prevenção, tratamento e complicações das atelectasias pulmonares em pediatria. Palavras-chave: atelectasis, children, pediatrics, mucus plugs, chest physiotherapy; atelectasias, criança, pediatria, fisioterapia respiratória, secreção brônquica. Utilizou-se o escore de Sackett DL, 1989 para a classificação do nível de evidência dos artigos encontrados. RESULTADOS:Foram analisados 45 artigos sobre atelectasias pulmonares, sendo 17 artigos em pediatria. Dos artigos com pacientes pediátricos, 13 estudos com série de casos clínicos, três artigos de revisão da literatura e um relato de caso, demonstrando que poucos artigos abordando atelectasias em pediatria foram publicados no período da pesquisa e que o nível de evidência dos artigos existentes são D e E. CONCLUSÃO: Poucos estudos clínicos foram realizados atualmente para identificar o tratamento mais eficaz para a resolução das atelectasias em pediatria. Embora a prática clínica tenha evoluído no tratamento das mesmas, com o aperfeiçoamento das técnicas de broncoscopia e da fisioterapia respiratória existe a necessidade da realização de estudos clínicos randomizados nesta área.

OBJECTIVE: To review the literature about mechanisms, diagnosis and treatment of atelectasis in the pediatric patient. METHODS: An electronic data search was carried out in Medline and Scielo using the following inclusion criteria for articles published between 1960 and 2007 about: atelectasis etiology, physiopathology, functional consequences, evaluation, prevention, treatment and complications, in pediatrics. The used key words were atelectasis, children, pediatrics, mucus plugs, chest physiotherapy; RESULTS: 45 pulmonary atelectasis articles were analyzed, 17 of them in pediatrics. Of the pediatric, 13 were case series, 3 literature reviews and one a case report. This demonstrates that there were few articles on atelectasis during the reviewed period and that these articles were at the D and E evidence level. CONCLUSION: No clinical trials were performed to identify s the most efficient treatment for atelectasis in the pediatric patient. Although clinical practice for treatment of atelectasis has evolved, mostly due to improvement of bronchoscopy and chest physiotherapy techniques, there is still a need to perform randomized clinical trials to address treatment of atelectasis in the pediatric patient.

Atelectasias durante anestesia: fisiopatologia e tratamento: [revisão] / Atelectasis during anesthesia: pathophysiology and treatment: [review]

JUSTIFICATIVA E OBJETIVOS: O colapso pulmonar intra-operatório é uma complicação de elevada incidência em pacientes submetidos à intervenção cirúrgica sob anestesia geral com relaxamento/paralisia da musculatura. Essa complicação está associada à piora das trocas gasosas no intra-operatório e, em alguns casos, necessidade de suporte respiratório prolongado no período pós-operatório. Os objetivos deste estudo foram revisar os aspectos fisiopatológicos da formação de atelectasias durante anestesia geral e as possíveis manobras terapêuticas para prevenir e tratar essa complicação. CONTEÚDO: Nesta revisão, os conceitos sobre a incidência de atelectasias intra-operatórias, os fatores relacionados com o seu desenvolvimento, tanto mecânicos quanto associados ao ajuste do respirador durante procedimento cirúrgico, os aspectos do diagnóstico e as estratégias de prevenção e tratamento foram abordados de maneira sistemática. CONCLUSÕES: A compreensão dos mecanismos relacionados com o desenvolvimento do colapso pulmonar durante o período intra-operatório, assim como o seu tratamento, pode contribuir para a redução da incidência de complicações pulmonares pós-operatórias, o tempo de recuperação e os custos hospitalares.

BACKGROUND AND METHODS: The incidence of intraoperative pulmonary collapse is elevated in patients undergoing surgery under general anesthesia with muscle relaxation/paralysis. This complication is associated with worsening intraoperative gas exchange and, in some cases, the need for prolonged postoperative respiratory support. The objective of this report was to review the pathophysiological aspects of atelectasis during general anesthesia and possible therapeutic maneuvers that could prevent and treat this complication. CONTENTS: This review discusses the concepts about the incidence of intraoperative atelectasis, factors that influence their development, both mechanical and those related to mechanical ventilator settings during the surgery, diagnostic criteria, and strategies to prevent and treat this complication. CONCLUSIONS: Understanding of the mechanisms related with the development of intraoperative pulmonary collapse, as well as its treatment, can contribute to reduce the incidence of postoperative pulmonary complications, the length of recovery and hospital costs.

JUSTIFICATIVA Y OBJETIVOS: El colapso pulmonar intraoperatorio es una complicación de elevada incidencia en pacientes sometidos a la intervención quirúrgica bajo anestesia general con relajamiento/parálisis de la musculatura. Esta complicación está asociada al empeoramiento de los cambios de gas en el intraoperatorio y en algunos casos, necesidad de soporte respiratorio prolongado en el período postoperatorio. Los objetivos de este estudio fueron los de revisar los aspectos fisiopatológicos de la formación de atelectasias durante anestesia general y las posibles maniobras terapéuticas para prevenir y tratar esa complicación. CONTENIDO: En esta revisión, los conceptos sobre la incidencia de atelectasias intraoperatorias, los factores relacionados a su desarrollo, tanto mecánicos como los relacionados al ajuste del respirador durante el procedimiento quirúrgico, los aspectos del diagnóstico y las estrategias de prevención y tratamiento fueron abordados de manera sistemática. CONCLUSIONES: La comprensión de los mecanismos relacionados al desarrollo del colapso pulmonar durante el período intraoperatorio, como también su tratamiento, pueden contribuir para la reducción de la incidencia de complicaciones pulmonares postoperatorias, el tiempo de recuperación y los costes de las internaciones en los hospitales.

Investigation of the Cause of Readmission to the Intensive Care Unit for Patients with Lung Edema or Atelectasis

PURPOSE: For patients with acute respiratory failure due to lung edema or atelectasis, Surplus lung water that is not removed during an initial stay in the Intensive Care Unit (ICU) may be related to early ICU readmission. Therefore, we performed a retrospective study of patient management during the first ICU stay for such patients. MATERIALS AND METHODS: Of 1,835 patients who were admitted to the ICU in the 36 months from January, 2003 to December, 2005, 141 were patients readmitted, and the reason for readmission was lung edema or atelectasis in 21 patients. For these 21 patients, correlations were investigated between body weight gain at the time of initial ICU discharge (weight upon discharge from the ICU ÷ weight when entering the ICU) and the time to ICU readmission, between body weight gain and the P/F ratio at ICU readmission, between the R/E ratio (the period using a respirator (R) ÷ the length of the ICU stay after extubation (E)) and the time to ICU readmission, between the R/E ratio and body weight gain, and between body weight gain until extubation and the time to extubation. RESULTS: A negative linear relationship was found between body weight gain at the time of initial ICU discharge and the time to ICU readmission, and between body weight gain at the time of ICU discharge and the P/F ratio at ICU readmission. If body weight had increased by more than 10% at ICU discharge or the P/F ratio was below 150, readmission to the ICU within three days was likely. Patients with a large R/E ratio, a large body weight gain, and a worsening P/F ratio immediately after ICU discharge were likely to be readmitted soon to the ICU. Loss of body weight during the period of respirator support led to early extubation, since a positive correlation was found between the time to extubation and body weight gain. CONCLUSION: Fluid management failure during the first ICU stay might cause ICU readmission for patients who had lung edema or atelectasis. Therefore, a key to the prevention of ICU readmission is to ensure complete recovery from lung failure before the initial ICU discharge. Strict water management is crucial based on body weight measurement and removal of excess lung water is essential. In addition, an apparent improvement in respiratory state may be due to respiratory support, and such an improvement should be viewed cautiously. Loss of weight at the refilling stage of transfusion prevents ICU readmission and may decrease the length of the ICU stay.

Progressive hypoxemia, hypercarbia and hyperthermia associated with prolonged anesthesia- a case report

The authors report a case of 66-year-old female patient, 55 kg, ASA I who, under general anesthesia in supine position, developed gradual hypoxemia [from a baseline PaO[2] of 250 to 91 mmHg], carbon dioxide build up [from a baseline PaCO[2] 31 to 41 mmHg] associated with gradual hyperthermia up to 38.3°C over seven hours, intra-operatively. These observations were noted while using a semiclosed carbon dioxide absorption circuit in conjunction with the Hygroster filter at a fresh gas flow of 4 1/min of 50% nitrous oxide in oxygen. While the ventilation pattern was unchanged throughout the procedure, there was a change in exhaled tidal and minute ventilation volume with a net decrease of 28 ml and 0.4 l/min respectively. Findings are probably the result of pulmonary atelecatasis under general anesthesia due to the use of a relatively high-inspired oxygen concentration [50%]. In addition, the use of a high humidity and temperature heat moisture exchanger [HME] filter [Hygroster] in conjunction with the circle absorber system may have resulted in over humidification and aggravated the pulmonary atelecatasis over the long operative time

Broncoscopia rígida en recién nacidos / Rigid bronchoscopy in newborns

Los autores evaluaron en un estudio prospectivo la utilidad y el riesgo de la broncoscopia rígida en recién nacidos. Se incluyeron en el estudio 28 neonatos, 17 de pretérmino y 11 de término, administrados en la unidad de Pediatría del Hospital Mocel entre septiembre de 1991 y febrero de 1992, por síndrome de dificultad respiratoria. En todos se practicó broncoscopia con instrumental rígido de 2.5 o 3 mm de diámetro externo. El procedimiento se llevó a cabo en la misma Unidad de Pediatría, sin sacar al niño de la cuna o de la incubadora térmica y con monitoreo de sus constantes vitales o metabólicas. La indicación más frecuente de broncoscopia (50 por ciento) fue la atelectasia lobar o de todo un pulmón, con obstrucción bronquial por tapones de moco. La atelectasia y la dificultad respiratoria desaparecieron después de aspirar los tapones mucosos y de permeabilizar la vía aérea. En el 18 por ciento de los casos se diagnosticó por broncoscopia algún tipo de malformacion de la vía aérea. No hubo defunciones ni complicaciones relacionadas con el procedimiento endoscópico