الفهرس 
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Abstract
Purpose
The Current Study Aimed To Compare Salbutamol Aerosol Delivery By Bi-Phasic Positive Airway Pressure (Bipap) Mode, At Two Different Pressures, With High Flow Nasal Cannula (HFNC ) (At Low Flow) In An Attempt To Find Out Which Would Be More Beneficial And To Help In Dose Adjustment When Changing from One Mode To Another.
Patients And Methods
In Vivo Study
The Study Included 36, Randomly selected, Acutely Exacerbated COPD Patients With Hypercapnia; Subdivided Into 3 Groups. Each group Was Given Salbutamol Using One Of The Three Different Delivery Methods; High Biphasic Postive Airway Pressure (IPAP/EPAP 20/5 Cm Water), Low Biphasic Postive Airway Pressure (IPAP/EPAP 10/5 Cm Water) Or High Flow Nasal Cannula System (HFNC) At Low Flow ; 5 L/Min.
Urine Samples Were Collected At 0.5 Hr Post Dosing And Cumulatively For 24 Hrs Post Dosing Indicating Pulmonary And Systemic Bioavailability.
Solid Phase Extraction (SPE) Followed By High Performance Liquid chromatography (HPLC) Were Used To Isolate And Quantify The Drug from Urine Samples.
Ex-Vivo Study
On The Third Day Of The Study, An Ex-Vivo Study Was Done By Inserting An Electrostatic Filter Between The Patient And The Administration Method. Then, The Amount Of Salbutamol Obtained By Sonication And Quantified By HPLC.
In Vitro Study
The Total Amount Of Salbutamol Delivered, Total Inhalable Dose (TID), To The Lung By The Three Previously Mentioned Delivery Methods Were Determined. Moreover, Particle Size characterization Of The Delivered Drug By The Three Methods Was Determined Using Anderson Cascade Impactor (ACI).
Results
In-Vivo Results
Using The Three Modes, Heart Rate (HR) Significantly Increased And Respiratory Rate (RR) Significantly Decreased (P<0.001), 30 Min Post Dose Compared To Baseline. Low Bipap Decreased The RR The Most Followed By HFNC Then High Bipap With No Significant Difference. Low Bipap Increased HR The Most Followed By High Bipap Then HFNC With No Significant Difference.
Both Pulmonary And Systemic Delivery Results Revealed That Low Pressure Bipap Showed The Highest Amount (And Percent Of Nominal Dose) Delivered To The Lung Followed By HFNC Then High Pressure Bipap. In Case Of Pulmonary Delivery, Significance Difference Was Only Observed Between Low And High Pressure Bipap Modes (P=0.012). In Systemic Delivery, Low Pressure Bipap Was Significantly Higher Than HFNC (P=0.017) And High Pressure Bipap (P=0.008).
Ex-Vivo Results
Ex- Vivo Delivery Results Revealed That Low Pressure Bipap Showed The Greatest Amount Of Drug On The Ex-Vivo Filter (And Percent Of Nominal Dose) Followed By HFNC Then High Pressure Bipap. Low Pressure Bipap Was Significantly Higher Than HFNC (P=0.033) And High Pressure Bipap (P=0.008).
In-Vitro Results
The Percent Of TID Delivered Using Bipap Mode At Low Inspiratory Pressure Was The Highest, Significantly Only With High Bipap (At P=0.014), Followed By HFNC Then Bipap At High Inspiratory Pressure. The HFNC System Had The Smallest Mass Median Aerodynamic Diameter (MMAD) Followed By Low Then High Inspiratory Pressure Bipap. The HFNC Was Significant Only from High Inspiratory Pressure Bipap (At P=0.002). There Was Also A Significant Difference Between High Inspiratory Pressure Bipap Mode And Low Inspiratory Pressure Bipap Mode (At P=0.027).
Conclusions
Increasing The IPAP In Bipap, from 10 To 20 Cm Water, Decreased The TID Percent And FPF Nearly By Half And Also Decreased The Pulmonary And Systemic Drug Delivery To The Patients Significantly. Using A High-Flow Nasal Cannula Delivered A TID That Was Non-Significant from That Delivered By Low Inspiratory Pressure Bipap. The Results Of The Current Study Suggest That There Must Be Dose Adjustment Upon Changing Between The Used Techniques.
Keys Words: Salbutamol, COPD, Bipap, HFNC, TID, Relative Lung Bioavailability.