Describe the importance of monitoring dead space during thoracic surgery, specifically during one-lung ventilation.
The concept of dead space has gained renewed interest among anesthesiologists ever since breath-by-breath measurement by volumetric capnography became available. Monitoring dead space during thoracic surgery assesses the ventilatory deficiencies related to increases in instrumental, airway and/or alveolar dead space, when ventilating patients with positive pressure and double-lumen tubes. Another interesting use of such monitoring is to detect ventilator-induced lung injury due to tidal overdistension. This type of injury threatens the fragile lungs especially during one-lung ventilation and can clinically be recognized as an increase in airway and alveolar dead space above normal values. To date, lung protective ventilation is based on the use of low tidal volumes and airway pressures to decrease overdistension. It has been shown to reduce the incidence of postoperative pulmonary complications after thoracic surgeries. However, such a ventilatory strategy impairs ventilation and induces hypercapnia due to increases in dead space. Therefore, continuous assessment of dead space is helpful in guiding ventilation and avoiding overdistension while maintaining the elimination of CO2 during thoracic surgery sufficiently high.
Monitoring dead space helps anesthesiologists monitor the status of the lung and find appropriate ventilatory settings during thoracic surgeries.
aDepartment of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina
bSwisstom AG, Landquart, Switzerland
cDepartment of Anesthesiology and Critical Care, Hedenstierna Laboratory, Uppsala University Hospital
dDepartment of Surgical Sciences, Uppsala University, Uppsala, Sweden
eCIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
Correspondence to Fernando Suarez-Sipmann, MD, PhD, Department of Anesthesiology and Critical Care, Department of Surgical Sciences, Hedenstierna Laboratory, Uppsala University Hospital, SE-75185 Uppsala, Sweden. Tel: +46 18 611 96 97; e-mail: Fsuarez.firstname.lastname@example.org