Non-dimensional physiological indices in medical diagnostics andinterventional guidelines: lung ventilatory index for weaning mechanically ventilated copd patients

Objectives: A Non-Dimensional Physiological Index (NDPI) is a dimensionless parameter that can help characterize an abnormal state associated with a particular physiological system. NDPIs can be used to effectively compare data across different studies The distribution of the values of such NDPIs in an extensive patient population can enable us to designate normal and disordered ranges of NDPI, with a critical value of NDPI separating these two ranges.This paper proposesaLung Ventilatory Index (LVI) and a non-dimensional index (LVI2) to provide the guidelines for successfully weaning mechanically ventilated Chronic Obstructive Pulmonary Disease (COPD) patients. Methodology: First, we have developed the Lung Ventilation Model (LVM) of the differential equation of lung volume response to driving pressureapplied by the ventilator to a COPD patient, involving the parameters of lung compliance (Ca) and airway resistance-to-airflow (Ra). The LVM is employed to determine the lung volume response to the applied ventilator pressure for intubated COPD patients to obtain the values of Caand Ra. Clinical Studies and Results: We used patient datafrom a clinical study to determine the values for LVI. We have shown thatLVI can distinguish between an intubated COPD patient and a weaned patient. We then developed a non-dimensional ventilatory index LVI2 that presents distinctly different values for an intubated COPD patient and a successfully weaned patient. Conclusions: In this paper, we have proposed anovel NDPI to differentiate intubated COPD patients from weaned patients. This non-dimensional ventilatory index LVI2can enable precision diagnosis of a successfully weaned COPD patient. In future work, we can test the efficacy of this LVI2index in assessing the need of COPD therapy in an intensive care unit for a larger patient population.