Role of BiPAP applied through endotracheal tube in unconscious patients suffering from acute exacerbation of COPD: a pilot study

Invasive mechanical ventilation using a bilevel PAP ST device in a healthy swine model

PURPOSE

The Coronavirus Disease 2019 (COVID-19) pandemic may cause an acute shortage of ventilators. Standard noninvasive bilevel positive airway pressure devices with spontaneous and timed respirations (bilevel PAP ST) could provide invasive ventilation but evidence on their effectiveness in this capacity is limited. We sought to evaluate the ability of bilevel PAP ST to effect gas exchange via invasive ventilation in a healthy swine model.

METHODS

Two single limb respiratory circuits with passive filtered exhalation were constructed and evaluated. Next, two bilevel PAP ST devices, designed for sleep laboratory and home use, were tested on an intubated healthy swine model using these circuits. These devices were compared to an anesthesia ventilator.

RESULTS

We evaluated respiratory mechanics, minute ventilation, oxygenation, and presence of rebreathing for all of these devices. Both bilevel PAP ST devices were able to control the measured parameters. There were noted differences in performance between the two devices. Despite these differences, both devices provided effective invasive ventilation by controlling minute ventilation and providing adequate oxygenation in the animal model.

CONCLUSIONS

Commercially available bilevel PAP ST can provide invasive ventilation with a single limb respiratory circuit and in-line filters to control oxygenation and ventilation without significant rebreathing in a swine model. Further study is needed to evaluate safety and efficacy in clinical disease models. In the setting of a ventilator shortage during the COVID-19 pandemic, and in other resource-constrained situations, these devices may be considered as an effective alternative means for invasive ventilation.

Application of BiPAP through Endotracheal Tube in Comatose Patients with COPD Exacerbation

Objective

To evaluate the effectiveness and safety of using BiPAP through endotracheal tube in comatose Chronic Obstructive Pulmonary Disease (COPD) patients with hypercapnic respiratory failure.

Methods

This is a prospective study done at Department of Chest Medicine, Jinnah Postgraduate Medical Centre, Karachi, during March to June 2017. It included all comatose COPD patients with hypercapnic respiratory failure who had a poor functional status prior to the illness and who did not meet the criteria to be kept on mechanical ventilator. Patients with apnea and other causes of coma were excluded. These patients were applied BiPAP through endotracheal tube and its response on blood gases and neurological status was evaluated.

Results

The success rate of BiPAP through endotracheal tube was 70.5% (31/44). Improvement in Glasgow Coma Scale (GCS) score (p<0.01), pH (p<0.01), and PaCO₂ (<0.01) was observed among the responders following two hours and 24 hours of therapy. No significant difference was found in response with regards to gender, smoking status, prior use of noninvasive ventilation or duration of disease. No complications were observed during the therapy.

Conclusion

In resource poor settings, the use of BiPAP through endotracheal tube can be an effective and safe intervention for comatose COPD patients with hypercapnic respiratory failure.

Noninvasive mechanical ventilation with average volume assured pressure support (AVAPS) in patients with chronic obstructive pulmonary disease and hypercapnic encephalopathy

BACKGROUND

Non-invasive mechanical ventilation (NIV) in patients with acute respiratory failure has been traditionally determined based on clinical assessment and changes in blood gases, with NIV support pressures manually adjusted by an operator. Bilevel positive airway pressure-spontaneous/timed (BiPAP S/T) with average volume assured pressure support (AVAPS) uses a fixed tidal volume that automatically adjusts to a patient's needs. Our study assessed the use of BiPAP S/T with AVAPS in patients with chronic obstructive pulmonary disease (COPD) and hypercapnic encephalopathy as compared to BiPAP S/T alone, upon immediate arrival in the Emergency-ICU.

METHODS

We carried out a prospective interventional match-controlled study in Guayaquil, Ecuador. A total of 22 patients were analyzed. Eleven with COPD exacerbations and hypercapnic encephalopathy with a Glasgow Coma Scale (GCS) <10 and a pH of 7.25-7.35 were assigned to receive NIV via BiPAP S/T with AVAPS. Eleven patients were selected as paired controls for the initial group by physicians who were unfamiliar with our study, and these patients were administered BiPAP S/T. Arterial blood gases, GCS, vital signs, and ventilatory parameters were then measured and compared between the two groups.

RESULTS

We observed statistically significant differences in favor of the BiPAP S/T + AVAPS group in GCS (P = .00001), pCO(2) (P = .03) and maximum inspiratory positive airway pressure (IPAP) (P = .005), among others. However, no significant differences in terms of length of stay or days on NIV were observed.

CONCLUSIONS

BiPAP S/T with AVAPS facilitates rapid recovery of consciousness when compared to traditional BiPAP S/T in patients with chronic obstructive pulmonary disease and hypercapnic encephalopathy.

TRIAL REGISTRATION

Current Controlled Trials application ref is ISRCTN05135218.