Albuterol Delivery by Metered-Dose Inhaler With a Pediatric Mechanical Ventilatory Circuit Model

Study Objective . To determine albuterol delivery by metered-dose inhaler (MDI) in an in vitro pediatric mechanical ventilatory circuit model. The influence of a spacing device, endotracheal tube (ETT) diameter and length, and air humidity was also investigated. Design . An albuterol MDI canister was connected to an AeroVent spacer or Airlife MDI adapter and ETT 4.0, 5.0, or 6.0 mm at commercially available and equal lengths. The ETT tip was attached to an in-line filter holder with a 1-μm type A/E glass fiber filter. Ventilator settings were fractional concentration of inspired oxygen 50%, tidal volume 250 ml, inspiratory:expiratory (I:E) ratio 1:3, rate 25 breaths/minute, temperature 35°C, and a decelerating flow pattern. Ten albuterol canisters were activated two times each (total 2000 μg) into dry (4.0-, 5.0-, and 6.0-mm ETT) and humidified air (4.0- and 6.0-mm ETT) and repeated in triplicate. Percentage MDI output was determined by weighing the filter before and after drug administration (balance sensitivity 10 μg). Significant differences (p≤0.05) among the groups with and without a spacer and in dry and humidified air were determined by ANOVA with Scheffe's multiple comparison test. Multiple regression was used to determine significant associations between ETT diameter and length and delivery. Main Results . With the AeroVent spacer in humidified air, delivery with the 4.0- and 6.0-mm ETT was approximately 2.3% and 5%, respectively. The spacer and dry air significantly improved delivery. Conclusions . In humidified air, the dose of albuterol by MDI with an AeroVent spacer should be doubled for children intubated with 6.0-mm ETT, and four puffs administered for every one puff desired for 4.0-mm ETT. The results of this investigation should prove useful in initial clinical trials of albuterol MDI in ventilator-dependent infants and children.     

Measuring clinical outcome

At the present time, there are many fundamental issues coming from the Department of Health or from other national organizations, which will have an effect on the future development of the dietetic profession. The British Diatetic Association (BDA) Professional Development Committee will consider these issues, as and when appropriate, and will publish the information in the form of Briefing Papers.
The first Briefing Paper on 'Quality Assurance' was published by the BDA in November 1989. The second on 'Measuring clinical outcome' is published below. In each case the opinion of BDA members and specialist groups has been sought and the Professional Development Committee wishes to thank individuals and the specialist groups for their comments.
The Briefing Papers are intended to provide information and promote discussion among the membership. I would welcome further comments from readers, which may be directed to the British Dietetic Association Office.     

Practice guidelines: the radiology perspective

Clinical practice guidelines have emerged as a reality for medical practitioners over the past 20 years. Although virtually all groups interested in the development of practice guidelines hope for improvements in patient care, secondary expectations vary widely among those using them. Their use in daily practice by physicians has met with resistance from barriers including concerns of “cookbook” medicine, a loss of autonomy, and increased professional liability. The recent experience of the ACR in addressing these challenges illustrates that physicians are receptive to steps perceived to mitigate the risks accompanying the use of guidelines as well as to efforts to increase their understanding of implementing guidelines in clinical practice. The experiences of other medical societies and an inventory of future trends reveal additional challenges associated with the use of practice guidelines, as third parties look to guidelines as points of reference for gauging the performance of health care providers.     

In vitro release of lectins by Phallusia mamillata hemocytes.

-Lactose specific lectins are released from Phallusia mamillata hemocytes during short-term cultures. The molecular weight of the subunits, the immunological cross-reaction and the sugar specificity suggest that the released lectins are similar to those isolated from the sonicated hemocytes. Because lectin release appears to take place independently of active protein synthesis, the possibility exists that lectins are pre-formed, stored in hemocytes and released when in vitro conditions stimulate the cells.     

APOE epsilon3 gene transfer attenuates brain damage after experimental stroke.

Apolipoprotein E (apoE, protein; APOE, gene) is the major lipid-transport protein in the brain and plays an important role in modulating the outcome and regenerative processes after acute brain injury. The aim of the present study was to determine if gene transfer of the epsilon3 form of APOE improves outcome in a murine model of transient focal cerebral ischaemia. Mice received an intrastriatal injection of vehicle, a second-generation adenoviral vector containing the green fluorescent protein gene (Ad-GFP) or a vector containing the APOE epsilon3 gene (Ad-APOE) 3 days before 60 mins focal ischaemia. Green fluorescent protein expression was observed in cells throughout the striatum and subcortical white matter indicating successful gene transfer and expression. ApoE levels in the brain were significantly increased after Ad-APOE compared with Ad-GFP or vehicle treatment. Ad-APOE treatment reduced the volume of ischaemic damage by 50% compared with Ad-GFP or vehicle treatment (13+/-3 versus 29+/-4 versus 27+/-5 mm(3)). The extent of postischaemic apoE immunoreactivity was enhanced in Ad-APOE compared with Ad-GFP or vehicle treated mice. These results show the ability of APOE gene transfer to markedly improve outcome after cerebral ischaemia and suggest that modulating apoE levels may be a potential strategy in human stroke therapy.