BackgroundA systematic literature review was conducted to (a) identify the most frequently used health-related quality of life (HRQOL) models and (b) critique those models.MethodsOnline search engines were queried using pre-determined inclusion and exclusion criteria. We reviewed titles, abstracts, and then full-text articles for their relevance to this review. Then the most commonly used models were identified, reviewed in tables, and critiqued using published criteria.ResultsOf 1,602 titles identified, 100 articles from 21 countries met the inclusion criteria. The most frequently used HRQOL models were: Wilson and Cleary (16%), Ferrans and colleagues (4%), or World Health Organization (WHO) (5%). Ferrans and colleagues’ model was a revision of Wilson and Cleary’s model and appeared to have the greatest potential to guide future HRQOL research and practice.ConclusionsRecommendations are for researchers to use one of the three common HRQOL models unless there are compelling and clearly delineated reasons for creating new models. Disease-specific models can be derived from one of the three commonly used HRQOL models. We recommend Ferrans and colleagues’ model because they added individual and environmental characteristics to the popular Wilson and Cleary model to better explain HRQOL. Using a common HRQOL model across studies will promote a coherent body of evidence that will more quickly advance the science in the area of HRQOL.

In this study, the internal position of a nasogastric/orogastric tube was determined in 72 children, prior to an abdominal radiograph, by measuring CO 2 and pH and bilirubin of tube aspirate. Fifteen of the 72 tubes (20.8%) were incorrectly placed on radiograph. Using the suggested adult cutoff of pH 5, pH of aspirate correctly predicted misplacement outside the stomach in 7/28 (25%) of children and correctly predicted correct placement in the stomach in 34 of 40 children (85%). Using the suggested adult cutoff of bilirubin ≥ 5 mg/dL, bilirubin monitoring failed to identify either of two incorrectly placed tubes. In this study, using an algorithm of assuming stomach placement if the pH of aspirate is ≤ 5 and obtaining an abdominal radiograph when either no aspirate is obtained or the pH is > 5 would have resulted in 92% accuracy. Alternatively, obtaining an abdominal radiograph would result in nearly 100% accuracy.

An abdominal radiograph is considered the "gold standard" for determining the position of flexible small-bore nasogastric/orogastric tubes. However, placement must be checked frequently while a tube is in place, and the summative radiation risk of multiple radiographs, as well as their expense, make the development of adequate bedside placement-locating methods imperative. Several methods of detecting tube placement have been investigated in adults, including: aspirating gastric contents and measuring the pH, bilirubin, pepsin, and trypsin levels; examining the visual characteristics of aspirate; placing the proximal end of the tube under water and observing for bubbles in synchrony with expirations; measuring the carbon dioxide level at the proximal end of the nasogastric/orogastric tube; auscultation for a gurgling sound over the epigastrium or left upper quadrant of the abdomen; and measuring the length from the nose/mouth to the proximal end of the tube. Many researchers have already concluded simple auscultation is not a reliable method to assess tube position because injection of air into the tracheobronchial tree or into the pleural space can produce a sound indistinguishable from that produced by injecting air into the gastrointestinal tract. In adults, only pH and bilirubin of aspirate have been shown both to reliably predict tube position and to have inexpensive simple bedside tests. In children, only pH of aspirate has been shown to be reliable. Research on gastric tube placement in children is relatively new because children are challenging to study in that they are considered a vulnerable population. This review of the literature includes results of both adult and pediatric studies. Tube placement error rates varied from 1.9% to 89.5% in adults and between 20.9% and 43.5% in children.

Age-specific methods have the potential to predict accurately the distances to the body of the stomach in 98.8% of children from 0.5 to 100 months of age and in 96.5% of children over 100 months of age. Where age-specific prediction methods cannot be used, the next best choice is the nose or mouth to ear-mid-xiphoid-umbilicus span.