Open AccessFeasibility of critical care ergometry: Exercise data of patients on mechanical ventilation analyzed as nine‐panel plots
Author(s) -
den Oever Huub L. A.,
Kök Mert,
Oosterwegel Aloys,
Klooster Emily,
Zoethout Siebrand,
Ruessink Erwin,
Langeveld Bas
Publication year - 2022
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.15213
Subject(s) - medicine , anaerobic exercise , oxygen pulse , ventilation (architecture) , respiratory minute volume , cardiology , heart rate , incremental exercise , mechanical ventilation , vo2 max , physical therapy , respiratory system , blood pressure , mechanical engineering , engineering
Nine‐panel plots are standard displays of cardiopulmonary exercise data, used in cardiac and pulmonary medicine to investigate the nature of exercise limitation. We explored whether this approach could be used to analyze the data of critically ill patients on mechanical ventilation, capable of exercising actively. Patients followed an incremental exercise protocol using a bedside cycle ergometer. Respiratory gases were analyzed using indirect calorimetry, and blood gases were sampled from arterial catheters. Data of seven patients were combined into nine‐panel plots. Systematic analysis clarified the nature of exercise limitation in six cases. Resting metabolic rate was increased in all patients, with a median oxygen uptake (V ˙ O 2 ) of 5.52 (IQR 4.29–6.31) ml/kg/min. Unloaded cycling increased theV ˙ O 2 by 19.8% to 6.61 (IQR 5.99–7.08) ml/kg/min. Adding load to the ergometer increased theV ˙ O 2 by another 20.0% to reachV ˙ O 2 peakat a median of 7.14 (IQR 6.67–10.75) ml/kg/min, corresponding to a median extrinsic workload of 7 W. This was accompanied by increased CO 2 production, respiratory minute volume, heart rate, and oxygen pulse. Three patients increased theirV ˙ O 2 to >40% of predictedV ˙ O 2 max , two patients passed the anaerobic threshold. Dead space ventilation was 44%, decreasing to 42% and accompanied by lower ventilatory equivalents during exercise. Exercise produced no net change in alveolo‐arterial PO 2 difference. We concluded that diagnostic ergometry in mechanically ventilated patients was feasible. Analysis of the data as nine‐panel plots provided insight into individual limitations to exercise.