PURPOSE: The application of NonInvasive ventilation (NIV) in Acute Hypoxaemic Respiratory Failure (AHRF) is still controversial. The pathophysiologic rationale supporting Continuous Positive Airway Pressure (CPAP) in nonhypercapnic AHRF is well established: the ability to reexpand alveoli improving oxygenation, allowing the recruitment of underventilated alveoli, enhancing clearance of airway secretions; to get mechanical bronchodilation, lowering airway resistance, reducing the collapse of small airways; to contrast inspiratory treshold imposed by intrinsic Positive End-Expiratory Pressure (PEEP), reducing dynamic hyperinflation, elastic respiratory workload, inspiratory effort; to increase functional residual capacity, favorably shifting the lung on its compliance curve, reducing the work of breathing. We investigated the influence of CPAP as first-line intervention in managing Acute Asthma (AA) patients.
METHODS: We evaluated a series of 10 patients admitted to our Emergency Departments (ED) for AHRF due to AA; 5 treated via Venturi mask, 5 with Boussignac device (PEEP 2-3 cm H2O, FIO2 0.6–0.9). Both groups had epidemiologic, clinical (dyspnoea grade, arterial blood pressure, heart rate, respiratory rate –RR) and arterial blood gas parameters recorded at entry and at 1 hour of treatment, without differences in medical therapy (systemic glucocorticosteroids, inhaled short acting β2-agonists using nebulizing systems).
RESULTS: Both groups showed similar improvement of all considered parameters, with no significant differences. CPAP sorted earlier and more sensible improvement in RR (“Venturi” group 31.2 ± 3.6 at entry, 24 ± 3.8 at 1 hour; “CPAP” group 30.8 ± 2.2 versus 21.8 ± 2.2) and subjective benefit (modified Borg dyspnoea scale: “Venturi” 5.6 ± 2.1 versus 3 ± 1.7; “CPAP” 5.6 ± 2.1 versus 1.8 ± 1.1). No adverse events were recorded.
CONCLUSION: In the ED the early initiation of NIV in AA can be useful: respiratory crises can be averted, respiratory fatigue prevented.
CLINICAL IMPLICATIONS: The overutilization of NIV is also a concern, if its inappropriate application leads to delay of needed intubation and squandering of resources. Carefully selected AA patients, closely monitored by an experienced, motivated staff with appropriate organization, can benefit of noninvasive CPAP treatment.
DISCLOSURE: Rodolfo Ferrari, No Financial Disclosure Information; No Product/Research Disclosure Information