NIMV is commonly used in treating respiratory failure in patients with COPD and CHF. Response to NIMV is assessed by arterial blood gases. Whether breathing pattern parameters can adequately assess clinical response to NIMV has not been evaluated. This study aimed at determining the efficacy of breathing pattern parameters as compared to ABGs in assessing response to NIMV.
Twenty patients with Type II Respiratory Failure were treated with NIMV using a Kimura KV3 ventilator delivered via a nasal CPAP mask. ABG and breathing pattern parameters were determined before, 4 hours after and on day 3 on NIMV. Breathing parameters studied included respiratory rate (RR), Percent ribcage contraction (%RC), Mean inspiratory flow (Vt/Ti), Total compartment displacement/tidal volume(TCD/VT), Fractional inspiratory time (Ti/T), Tidal volume(TV) and Minute ventilation(MV).
Mean age was 56± 10.6 years; 80% were males, 20% females.The studied parameters are shown in Table 1.
ParametersPre-NIMV4HRS- Post3 DaysppH7.267.357.42<0.00005PCO2856950<0.00005PO2525858.5<0.005O2 SAT(%)79.784.489.5<0.05RR302623<0.05VT(%)95.510599.3NSVE (%)9110497.4NS%RC624851<0.00005Ti/T.34.34.34NSTCD/VT1.041.041.03NSVT/Ti101.511198NS
The improvement in respiratory failure with NIMV, as evident by ABG parameters was also reflected by changes in certain breathing pattern parameters such as percent rib cage contraction and respiratory rate.
Instead of frequent ABGs, certain breathing pattern parameters such as percent ribcage contraction and respiratory rate could be used to assess response to NIMV. Larger studies are needed to confirm this.
B. Datta, None.