Atelectrauma or volutrauma: the dilemma

Critical care medicine is a highly complex field where diagnosing diseases and selecting effective therapies pose daily challenges for clinicians. In critically ill patients, biomarkers can play a crucial role in identifying and addressing clinical problems. Selecting the right biomarkers and utilizing them effectively can lead to more informed decisions, ultimately impacting patient outcomes. However, each biomarker has its strengths and limitations, making a thorough understanding essential for accurate diagnosis and treatment management. For instance, neuron-specific enolase (NSE) is commonly used to predict outcomes in out-of-hospital cardiac arrest (OHCA), procalcitonin (PCT) levels strongly correlate with bacterial infections, and NT-proBNP serves as a reliable indicator of cardiac stress. Additionally, serum creatinine (SCr) remains fundamental in renal diagnostics, while prealbumin helps differentiate catabolic and anabolic phases in critically ill patients. This narrative review highlights a carefully selected set of biomarkers known for their clinical utility and reliability in guiding critical care decisions. Further refining the application of biomarkers—especially by integrating them into a multimodal approach—will enhance clinicians’ ability to navigate the challenges of critical care, always striving to improve patient outcomes.

The improvement in oxygenation after helmet application in hypoxemic patients may be explained by the alveolar recruitment obtained with positive end expiratory pressure (PEEP) or by the administration of a more accurate inspiratory fraction of oxygen (F_iO₂). We have designed the “ZEEP-PEEP test”, capable to distinguish between the F_iO₂-related or PEEP-related oxygenation improvement. Our primary aim was to describe the use of this test during helmet CPAP to assess the oxygenation improvement attributable to PEEP application. We performed a prospective physiological study including adult critically ill patients. Respiratory and hemodynamic parameters were recorded before helmet application (PRE step), after helmet application without PEEP (ZEEP step) and after the application of the PEEP valve (PEEP step), while maintaining a constant FiO₂. We defined as “PEEP responders” patients showing a PaO₂/FiO₂ ratio improvement ≥10% after PEEP application. 93 patients were enrolled. Compared to the PRE step, PaO2/FiO2 ratio was significantly improved during helmet CPAP both at ZEEP and PEEP step (189 ± 55, 219 ± 74 and 241 ± 82 mmHg, respectively, p < 0.01). Both PEEP responders (41%) and non-responders showed a significant improvement of PaO2/FiO2 ratio after the application of helmet at ZEEP, PEEP responders also showed a significant improvement of oxygenation after PEEP application (208 ± 70 vs 267 ± 85, p < 0.01). Helmet CPAP improved oxygenation. This improvement was not only due to the PEEP effect, but also to the increase of the effective inspired FiO₂. Performing the ZEEP-PEEP test may help to identify patients who benefit from PEEP.

Introduction - Critical care medicine is a complex activity where knowledge, experience, intuition, and sometimes even luck converge. Diagnosing diseases and selecting effective therapies represent a daily challenges for clinicians, requiring them to analyze and process vast amounts of information. Patient’s medical history, clinical signs and symptoms, laboratory results, and radiological findings are just some of the elements that must be considered during routine practice. At times, the sheer volume of data can overwhelm doctors, exposing them to the risk of becoming lost in a maze of irrelevant information. This narrative review focuses on a curated set of biomarkers renowned for their reliability in supporting clinical decision-making. By leveraging these tools, we aim to streamline decision-making processes and enhance patient outcomes in the ICU’s high-stakes environment.