RESUMEN
BACKGROUND: During mechanical ventilation medical aerosol delivery has been reported to be upto two fold greater with dry inhaled gas than with heated humidity. Urine levels at 0.5 h post dose (URSAL0.5%) has been confirmed as an index of lung deposition and 24 h (URSAL24%) as index of systemic absorption. Our aim was to determine the effect of humidification and aerosol device type on drug delivery to ventilated patients using urine levels. METHODS: In a randomized crossover design, 36 (18female) mechanically ventilated patients were assigned to one of three groups. Groups 1 and 2 received 5000 µg salbutamol using vibrating mesh (VM) and jet nebulizers (JN), respectively, while group 3 received 1600 µg (16 puffs) of salbutamol via metered dose inhaler with AeroChamber Vent (MDI-AV). All devices were placed in the inspiratory limb of ventilator downstream from the humidifier. Each subject received aerosol with and without humidity at >24 h intervals with >12 h washout periods between salbutamol doses. Patients voided urine 15 min before each study dose and urine samples were collected at 0.5 h post dosing and pooled for the next 24 h. RESULTS: The MDI-AV and VM resulted in a higher percentage of urinary salbutamol levels compared to the JN (p < 0.05). Urine levels were similar between humidity and dry conditions. CONCLUSIONS: Our findings suggest that in-vitro reports overestimate the impact of dry vs. heated humidified conditions on the delivery of aerosol during invasive mechanical ventilation.
Asunto(s)
Albuterol/farmacocinética , Pulmón/metabolismo , Inhaladores de Dosis Medida , Respiración Artificial/métodos , Administración por Inhalación , Aerosoles/administración & dosificación , Aerosoles/farmacocinética , Albuterol/administración & dosificación , Disponibilidad Biológica , Broncodilatadores/administración & dosificación , Broncodilatadores/farmacocinética , Estudios Cruzados , Diseño de Equipo , Femenino , Humanos , Humidificadores/estadística & datos numéricos , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND: Inhaled-medication delivered during mechanical-ventilation is affected by type of aerosol-generator and humidity-condition. Despite many in-vitro studies related to aerosol-delivery to mechanically-ventilated patients, little has been reported on clinical effects of these variables. The aim of this study was to determine effect of humidification and type of aerosol-generator on clinical status of mechanically ventilated asthmatics. METHOD: 72 (36 females) asthmatic subjects receiving invasive mechanical ventilation were enrolled and assigned randomly to 6 treatment groups of 12 (6 females) subjects each received, as possible, all inhaled medication using their assigned aerosol generator and humidity condition during delivery. Aerosol-generators were placed immediately after humidifier within inspiratory limb of mechanical ventilation circuit. First group used vibrating-mesh-nebulizer (Aerogen Solo; VMN) with humidification; Second used VMN without humidification; Third used metered-dose-inhaler with AeroChamber Vent (MDI-AV) with humidification; Forth used MDI-AV without humidification; Fifth used Oxycare jet-nebulizer (JN) with humidification; Sixth used JN without humidification. Measured parameters included clinical-parameters reflected patient response (CP) and endpoint parameters e.g. length-of-stay in the intensive-care-unit (ICU-days) and mechanical-ventilation days (MV-days). RESULTS: There was no significant difference between studied subjects in the 6 groups in baseline of CP. VMN resulted in trend to shorter ICU-days (â¼1.42days) compared to MDI-AV (p = 0.39) and relatively but not significantly shorter ICU-days (â¼0.75days) compared JN. Aerosol-delivery with or without humidification did not have any significant effect on any of parameters studied with very light insignificant tendency of delivery at humid condition to decrease MV-days and ICU-days. No significant effect was found of changing humidity during aerosol-delivery to ventilated-patient. CONCLUSIONS: VMN to deliver aerosol in ventilated patient resulted in trend to decreased ICU-days compared to JN and MDI-AV. Aerosol-delivery with or without humidification did not have any significant effect on any of parameters studied. However, we recommend increasing the number of patients studied to corroborate this finding.