Obesity is a growing health issue associated with changes in respiratory physiology, including decreased lung compliance, increased airway resistance, and impaired gas exchange. These changes may impact patients requiring mechanical ventilation. Over 40% of adults in the United States meet criteria for obesity, highlighting the clinical relevance of this population in ICU settings. This literature review evaluates the relationship between body mass index (BMI) and duration of mechanical ventilation in critically ill patients. A literature review was conducted using studies from the last ten years examining BMI in relation to mechanical ventilation outcomes. Databases, including Google Scholar, were used to identify articles. Search terms included obesity, mechanical ventilation, and ICU. Ten studies focusing on adult ICU populations reporting ventilation duration or weaning outcomes were evaluated and then included. Across studies, higher BMI was associated with prolonged mechanical ventilation and more complex weaning. Obese patients were more likely to experience delayed weaning, with some studies suggesting delays of several days compared to normal BMI patients. This is likely due to decreased chest wall compliance and increased work of breathing. However, findings were inconsistent. Some studies reported that BMI was not an independent factor when controlling for confounders such as illness severity and comorbidities. Evidence suggests an obesity paradox, where obese patients may have similar or lower mortality despite longer ventilation duration. Limitations include reliance on observational data. Overall, increased BMI appears associated with longer mechanical ventilation duration, though its independent impact remains unclear. Further research is needed to clarify this relationship.
