Evidence of Aspiration Risk is the research study I have chosen to review. The goal of conducting any research experiments is to accurately test a hypothesis in an unbiased format and derive valid trustworthy results. The internal validity of a study is the proven relationship between the independent variable and the outcome of the study (Polit & Beck, 2017). If the findings of a study can be explained in a way other then it is being presented, the internal validity of the study is automatically weakened. Quasi-experimental studies have a higher risk of issues with internal validity than other research designs (Polit & Beck, 2017). Researchers must plan to prevent any possible ambiguity or threats to the internal validity of their study by using control mechanisms such as selection biases.
Questioning the Internal Validity
I read the “Methods” section of the aspiration risk-reduction study as instructed in this week’s discussion post instructions, and I immediately had questions. Before reading the entire study, my thoughts were: What was the age (or age range), gender, and comorbidities of all of the patients involved? Did they all have the same vent settings? How sedated were they? Was there a suctioning schedule followed for both groups? Was the same suction equipment used in all of the patients? What method was used to determine their target feeding goal? Were they all bolus fed through the feeding tube or around the clock fed? Did they all receive free water flushes? Were the feedings held based on residual? How often was residual checked? Did any of them have a diagnosis of upper GI bleed? Were they all on a peptic ulcer prevention drug? In which part of the lung was pneumonia found? Did they only consider the right upper lobe “aspiration pneumonia”?
These are just to name a few of the questions that I had surrounding this study. After reading the entire study many of the questions I mentioned above were answered. However, I still found that some of the specific questions I had were not addressed. Had the researcher discussed some of the variables that could have impacted the outcome it would have strengthened the internal validity of the study. Additionally, of the data described in this study does question the internal validity as both groups that were monitored and compared for aspiration were treated differently. The usual care group did not address guidelines regarding head of the bed elevation, nor did the nurses have formal training regarding insertion of small-bowel feeding tubes, and the gastric residual volumes were not regulated. Whereas the Aspiration Risk-Reduction Protocol (ARRP) group had guidelines to follow for all of the above (Metheny, Davis-Jackson, & Stewart, 2010). Because this is an older study and I am very familiar with the CDC “VAP Bundle”, and it is fairly common knowledge that keeping the head of the bed up helps prevent pneumonia and aspiration. With all of the variables in this study, the external validity is questioned, meaning how can this research pinpoint what was most effective. With that said, despite my personal experience and additional questions, I feel that the findings do concur with current practice as it related to keeping the head of the bed up. However, have never seen feeding tubes placed in the small bowel below the pylorus.
Failing to consider validity
Statistical validity is the relationship between variables which can be simply described as the hypothesized cause and effect. Where construct validity is the inferences made from the specific settings, outcomes, or treatments, and external validity helps determine if the results of the study can be applied to various people, settings, and treatment (Polit & Beck, 2017). If any area of validity in a study is in question, that can potentially compromise the overall validity of the study, leaving the learner to question all aspects of the research.
Metheny, N., Davis-Jackson, J., & Stewart, B. (2010). Effectiveness of an aspiration
risk-reduction protocol. Nursing Research, 59(1), 18-25.
Polit, D. F., & Beck, C. T. (2017). Nursing research: Generating and assessing evidence for
nursing practice (10th ed.). Philadelphia, PA: Wolters Kluwer.