[The basics on mechanical ventilation support in acute respiratory distress syndrome]

Equations for calculating ideal body weight in patients on mechanical ventilation in adult intensive care units in Latin America: exploratory review

Introduction: Ideal body weight calculation is used in critical medicine for drug dosing and setting ventilation parameters. However, the suggested and used equations were designed on the basis of anthropometric variables that do not represent the Latin American population. Objective: To map and present the current evidence on the equations used to calculate ideal weight in patients on mechanical ventilation in intensive care units in Latin America. Material and Methods: Exploratory review using the Joanna Briggs Institute method conceived by Arskey / O’Malley. A search was performed in the BVS, LILLACS, REDALYC, Ovid, Google Scholar and Scielo databases using keywords and MeSH terms in Spanish, English, and Portuguese, with no time limitation. The results are presented in descriptive tables. Results: Overall, 1126 studies were identified and 1120 were excluded; 6 studies were reviewed and 3 additional studies were identified through a manual search. The studies were published in Chile, Brazil, Mexico, Ecuador, and Peru. In 89%, the ARDS Network equation was used to calculate tidal volume. Acute respiratory distress syndrome was the most reported pathology (33%). Conclusions: Adult intensive care units in Latin America use the equation suggested by the ARDS Network, which was designed in a population with different anthropometric characteristics.

Electrical impedance tomography

Continuous assessment of respiratory status is one of the cornerstones of modern intensive care unit (ICU) monitoring systems. Electrical impedance tomography (EIT), although with some constraints, may play the lead as a new diagnostic and guiding tool for an adequate optimization of mechanical ventilation in critically ill patients. EIT may assist in defining mechanical ventilation settings, assess distribution of tidal volume and of end-expiratory lung volume (EELV) and contribute to titrate positive end-expiratory pressure (PEEP)/tidal volume combinations. It may also quantify gains (recruitment) and losses (overdistention or derecruitment), granting a more realistic evaluation of different ventilator modes or recruitment maneuvers, and helping in the identification of responders and non-responders to such maneuvers. Moreover, EIT also contributes to the management of life-threatening lung diseases such as pneumothorax, and aids in guiding fluid management in the critical care setting. Lastly, assessment of cardiac function and lung perfusion through electrical impedance is on the way.

[Acute respiratory distress syndrome: a review of the Berlin definition]

Acute Respiratory Distress Syndrome (ARDS) is due to many causes. The absence of a universal definition up until now has led to a series of practical problems for a definitive diagnosis. The incidences of ARDS and Acute Lung Injury (ALI) vary widely in the current literature. The American-European Consensus Conference definition has been applied since its publication in 1994 and has helped to improve knowledge about ARDS. However, 18 years later, in 2011, the European Intensive Medicine Society, requested a team of international experts to meet in Berlin to review the ARDS definition. The purpose of the Berlin definition is not to use it as a prognostic tool, but to improve coherence between research and clinical practice.