Search

JUSTIFICATIVA E OBJETIVOS: A posição em decúbito ventral (posição prona) aplicada em pacientes com síndrome do desconforto respiratório agudo (SDRA), tem demonstrado melhora da oxigenação em mais de 70% dos casos. Uma vez que essa posição promove uma série de alterações pulmonares, inclusive na mecânica pulmonar, abre-se a hipótese da necessidade de otimizar os parâmetros ventilatórios após a instalação deste novo decúbito, principalmente do valor da pressão positiva expiratória final (PEEP). O objetivo deste estudo foi avaliar a influência da posição prona no cálculo da PEEP ideal, titulada pela melhor complacência pulmonar e comparar as alterações pulmonares de mecânica, de oxigenação e de ventilação nas posições supina e prona. MÉTODO: Estudo prospectivo realizado no Serviço de Terapia Intensiva da Irmandade Santa Casa de Misericórdia de São Paulo. Foram comparadas três fases. Fase 1: na posição supina, após o cálculo de PEEP ideal. Fase 2: após duas horas o decúbito do paciente era modificado para prona, após cálculo da PEEP. O paciente era mantido por seis horas neste decúbito. Fase 3: após este período, era colocado na posição supina, realizando-se novo cálculo da PEEP e nova coleta gasométrica, após duas horas. Foi comparada a fase 1 versus fase 2, fase 2 versus fase 3 e fase 3 versus fase 1. RESULTADOS: Não foram encontradas diferenças nos valores de PEEP ideal nas três fases do estudo: fase 1 = 14 ± 4,43, fase 2 = 14,73 ± 4,77 e fase 3 = 13,65 ± 4,92. CONCLUSÕES: Não houve diferença de PEEP ideal quando na posição prona ou supina. Portanto, de acordo com este estudo não há necessidade de se readequar a PEEP a cada mudança de decúbito.BACKGROUND AND OBJECTIVES: In acute respiratory discomfort syndrome (ARDS) patients, prone position improves oxygenation in more than 70% of the cases. It is well known that prone position promotes a lot of pulmonary changes, including pulmonary mechanics, so we hypothesized that there is the necessity to optimize the ventilatory parameters after the patient is placed in prone position, especially the positive end expiratory pressure (PEEP) values. The objective of this study valued the influence of the prone position at the calculation of the ideal PEEP, given a title by the best pulmonary complaisance and he compared the pulmonary alterations of mechanics, of oxygenation and of ventilation in the positions supine and prone. METHODS: Prospective study, taken place in the Irmandade Santa Casa de Misericórdia de São Paulo Intensive Care Service. Three fases have been compared. Fase 1: in supine position, after the best PEEP calculation. Fase 2: two hours after the patient was placed in prone position and the best PEEP was calculated. The patient was kept for 6 hours in this position. Fase 3: after this time, patient was placed in supine again and after two hours, a new best PEEP calculation and arterial gas analysis was done. And then fase1 versus fase 2, fase 2 versus fase 3, fase 3 versus fase1 were compared. RESULTS: There were no differences in the PEEP values found in all study fases: fase 1 = 14 ± 4.43; fase 2 = 14.73 ± 4.77 and fase 3 = 13.65 ± 4.92. CONCLUSIONS: There were no differences in best PEEP values between prone and supine position. Therefore, there is no need to recalculate the PEEP value after each position change.

Background: During general anesthesia, mechanical ventilation can cause pulmonary damage through mechanism of ventilator-induced lung injury, which is a major cause of post-operative pulmonary complications, which varies between 5 and 33% and increases the 30-day mortality of the surgical patient significantly., Objective: The aim of this review is to analyze different variables which played a key role in the safe application of mechanical ventilation in the operating room and emergency setting., Methods: Also, we wanted to analyze different types of the population that underwent intraoperative mechanical ventilation like obese patients, pediatric and adult population and different strategies such as one lung ventilation and ventilation in trendelemburg position. The peer-reviewed articles analyzed were selected according to PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) from Pubmed/Medline, Ovid/Wiley and Cochrane Library, combining key terms such as: "pulmonary post-operative complications", "protective ventilation", "alveolar recruitment maneuvers", "respiratory compliance", "intraoperative paediatric ventilation", "best peep", "types of ventilation". Among the 230 papers identified, 150 articles were selected, after title - abstract examination and removing the duplicates, resulting in 94 articles related to mechanical ventilation in operating room and emergency setting that were analyzed., Results: Careful preoperative patient's evaluation and protective ventilation (i.e., use of low tidal volumes, adequate PEEP and alveolar recruitment maneuvers) has been shown to be effective not only in limiting alveolar de-recruitment, alveolar overdistension and lung damage, but also in reducing the onset of Pulmonary Post-operative Complications (PPCs)., Conclusion: Mechanical ventilation is like "Janus Bi-front" because it is essential for surgical procedures, for the care of critical care patients and in life-threatening conditions, but it can be harmful to the patient if continued for a long time and where an excessive dose of oxygen is administered into the lungs. Low tidal volume is associated with a minor rate of PPCs and other complications and every complication can increase the length of Stay, adding cost to NHS between 1580 € and 1650 € per day in Europe and currently the prevention of PPCS is the only weapon that we possess., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

In patients ventilated for acute respiratory failure PEEP was changed either by gradual increase and decrease (5 cm H2O/min) or in steps of 5 cm H2O. The effects on gas exchange, pulmonary mechanics and pulmonary and systemic circulation were studied. Total compliance did not change uniformly and cardiac index decreased so much due to PEEP that the increase in PaO2 could not prevent the decrease of arterial oxygen transport. No variable was found helpful to predict the "best PEEP" in a clinical situation. [ABSTRACT FROM AUTHOR]

We assessed hemodynamics, total lung and chest wall compliance (CT) and gas exchange using two different levels of PEEP during controlled ventilation in two different groups of patients with ARF; in the first group (Group 1, 12 patients) chest X-Rays showed a symmetrical pattern of bilateral alveolar infiltrates; in the second group (Group 2, 5 patients) chest X-Ray showed a asymmetrical pattern with unilateral lobar consolidation. A first level of PEEP (best PEEP = 9 +/- 3 cm H2O) produced an improvement in CT and in gas exchange with a slight decrease in cardiac index in both groups; but improvement in PaO2 (from 64 +/-33 to 122 +/- 76 torr, p less than 0.001 in Group 1, and from 76 +/- 39 to 91 +/- 33 torr, p less than 0.05 in Group 2) and decrease in QS/QT were not as well marked in Group 2 as i Group 1. A second level of PEEP (high level PEEP: 20 +/- 4 cm H2O) produced a sharp decrease in CT and required hemodynamic support in each case (blood volume expansion with or without Dopamine infusion) to maintain cardiac index within a normal range. In Group 1 this high level PEEP produced a greater improvement in gas exchange (PaO2 increased from 122 +/- 76 to 194 +/- 76, p less than 0.01) but in Group 2 it had a deleterious effect, producing a decrease in PaO2 (from 91 +/- 33 to 76 +/- 41 torr, p less than 0.05), and an increase in QS/QT; with this higher PEEP we also noted an increase of alveolar dead space in Group 2. This study demonstrates the efficiency of high levels of PEEP to reduce QS/QT in ARF but also shows its limitations: namely reduction in cardiac performance and in efficiency if the damage to one lung is significantly more pronounced than that to the other lung. [ABSTRACT FROM AUTHOR]