Examining Methodology and Design: Capnography During Resuscitation

The evaluation of the use of capnography during resuscitation among patients of a coronary care unit (CCU) may be developed in a variety of ways, including qualitative, quantitative, and mixed-methods studies. Pantazopoulos et al. (2015) define capnography as a method to measure the level of end-tidal carbon dioxide (ETCO2) and coronary perfusion pressure (CPP). This process is not frequently used in CCUs because of the lack of background knowledge and staff experience. In this paper, special attention will be paid to three research approaches to capnography use (i.e., qualitative, quantitative, and mixed-methods), including their external and internal validity and an assessment of their benefits in proving the appropriateness of capnography for cardiac patients and medical workers during resuscitation.

External and Internal Validity

Reliability and validity have to be properly applied to each research instrument as these concepts define whether the research goes as it is supposed to, and if obtained results are as consistent as expected. Internal validity is the extent to which the results contain the truth about the population and the topic. External validity explains the extent to which the results may be generally applied in practice (Patino & Fereeira, 2018). The increasing use of capnography in different healthcare units will lead to further opportunities to predict more extensively the duration of cardiopulmonary resuscitation (CPR) (Kodali & Urman, 2014). Its current limited implementation, and the potential benefits, should be investigated. Three main studies have been chose to be analyzed in terms of their validity.

Qualitative, quantitative, and mixed-methods studies all have their strong and weak aspects. Iyer, Koziel, and Langhan (2015) offered a qualitative evaluation of capnography on the basis of a grounded theory approach. Turle, Sherren, Nicholson, Callaghan, and Shepherd (2015) developed a quantitative study within several UK hospitals through a telephone questionnaire to explain the use of capnography among patients who experience cardiac arrest. Finally, Langhan, Kurtz, Schaeffer, Asnes, and Riera (2014) chose mixed-methods analysis to describe capnography experiences in acute care settings and defined the most effective implementation strategies. All these studies were introduced in peer-reviewed journals, proving their validity and credibility.

Validity aims to explain how well the gathered information covers the chosen area of research. In this case, the topic for analysis is the use of capnography during resuscitation. Iyer et al. (2015) developed a qualitative study with subjective and interpretive data. The researcher is the main instrument in a study, meaning that his or her abilities and knowledge affects the quality of the findings. Threats usually arise from the presentation and interpretation of the data. In this article, research was conducted rigorously, including the clear outlining of the established goals, chosen methods, a defined sample, and the obtained results. Therefore, it is possible to say that the study has internal validity. The same outcomes are observed in the articles by Turle et al. (2015) and Langhan et al. (2014). The authors succeeded in the introduction in setting out clear goals and properly described their methods of data gathering and analysis. All the hospitals and participants met the inclusion criteria, and ideas were generated to build theories and new implementation strategies.

External validity was also present in all three studies as it was possible to say that their findings could be applied to different hospital settings to improve the quality of patient care. For example, Langhan et al. (2014) identified the factors that fostered capnography use, and Turle et al. (2015) investigated the availability of capnography during cardiac arrest within all the departments of the hospital. The grounded theory approach of Iyer et al. (2015) addressed more general themes, such as nurse experiences and knowledge, attitudes towards capnography use, and barriers based on the lack of comfort or knowledge. Capnography could be applied in treating either pediatric or adult patients, and be effective if nurses and other medical workers have the appropriate knowledge background.


Each study made a significant contribution to the discussion of capnography use in a CCU. One of the strengths of the work presented by Iyer et al. (2015) was the possibility to obtain a full breadth of opinions about capnography and consider the changes that could be observed in personal and professional practice. Human experiences and emotions were not ignored, which improved the quality of research. The results helped the participants to understand their weaknesses while working with capnographers, and enabled them to choose the direction for further improvements and developments. Finally, grounded theory as the main method of a qualitative exploratory design provided a diverse nature of participants who gave a variety of responses in terms of which a common understanding of capnography was encouraged. In this study, everything was clear: capnography was a phenomenon for analysis, nurses and physicians were the interviewees who shared their opinions, and the researcher was the instrument to gather and analyze the data.

The major benefit of a quantitative study is the opportunity to measure the results and answer the research questions using objective data. Turle et al. (2015) defined cardiac arrest as one of the more serious complications in the emergency department (ED) and capnography as one of the possible solutions to control endotracheal tube placement in patients who have a cardiac arrest. A questionnaire was organized via a telephone to investigate the utilization of capnography at EDs and intensive care units (ICUs). Statistical data was introduced to explain the use of capnography during different cardiac scenarios, proving that this method could hardly lead to arrest or be used to make a prognosis regarding health complications. However, capnography was proved to be an effective means to control the placement of an endotracheal tube, detect the return of spontaneous circulation (ROSC), and succeed in cardiopulmonary resuscitation (Turle et al., 2015). The results proved the worth of capnography in different departments of the same hospital.

A mixed-methods study is characterized by a combination of qualitative and quantitative information. Langhan et al. (2014) focused their attention on the investigation of the reasons for limited implementation of capnography. Compared to the previous studies, this mixed-method approach with grounded theory, iterative data analysis, and a constant comparative method contributed to the generation of knowledge about capnography, the formulation of ideas, and the creation of new theories on how to foster the use of capnography. The benefits of this design include data exploration and analysis, the use of words and numbers in findings, and the reduction of personal biases in the discussion.


In general, the chosen three articles all have specific strengths and limitations, depending on their methodologies and designs. On the one hand, a qualitative study creates an opportunity to gather general information and utilize it in different hospital units to improve patient care and health outcomes. On the other hand, the benefits of a quantitative study cannot be ignored because statistics serve as one of the best and strongest evidence for capnography utilization in the modern healthcare system. At the same time, instead of choosing between qualitative and quantitative data, Langhan et al. (2014) used a mixed-methods approach to combine the results of both studies. However, the question about its validity and reliability remains open because the researcher has to work hard and cooperate with a team of experts to check the worth of each statement. A final choice of methodology for investigating the use of capnography during resuscitation depends on the researcher’s readiness, available resources, and the deadlines set for the study. In all three cases, the topic of capnography was properly described, proving the presence of internal and external validity that is expected from qualitative and quantitative researchers.


Iyer, N. S., Koziel, J. R., & Langhan, M. L. (2015). A qualitative evaluation of capnography use in paediatric sedation: Perceptions, practice and barriers. Journal of Clinical Nursing, 24(15-16), 2231–2238. Web.

Kodali, B. S., & Urman, R. D. (2014). Capnography during cardiopulmonary resuscitation: Current evidence and future directions. Journal of Emergencies, Trauma, and Shock, 7(4), 332-340. Web.

Langhan, M. L., Kurtz, J. C., Schaeffer, P., Asnes, A. G., & Riera, A. (2014). Experiences with capnography in acute care settings: A mixed-methods analysis of clinical staff. Journal of Critical Care, 29(6), 1035–1040. Web.

Pantazopoulos, C., Xanthos, T., Pantazopoulos, I., Papalois, A., Kouskouni, E., & Iacovidou, N. (2015). A review of carbon dioxide monitoring during adult cardiopulmonary resuscitation. Heart, Lung and Circulation, 24(11), 1053-1061. Web.

Patino, C. M., & Fereeira, J. C. (2018). Internal and external validity: Can you apply research study results to your patients? Journal Brasileiro de Pneumologia, 44(3), 183. Web.

Turle, S., Sherren, P. B., Nicholson, S., Callaghan, T., & Shepherd, S. J. (2015). Availability and use of capnography for in-hospital cardiac arrests in the United Kingdom. Resuscitation, 94, 80–84. Web.


Table 1. Comparison of Methodologies and Designs.

Type of Article Title of Article Type of Analysis and Rationale (can be more than one) Applicability of Test Reliability and Validity
Quantitative “Availability and use of capnography for in-hospital cardiac arrests in the United Kingdom”. Microsoft Excel spreadsheet software was used to analyze data of the study. The goal of this quantitative research was to quantify the availability of ETCO2monitoring among patients who have cardiac arrests. Monitoring evaluation proves that waveform capnography was frequently used in the majority of emergency cases, compared to other methods, such as disposable colorimetric devices or quantitative devices. A description of the current application of capnography during cardiopulmonary resuscitation was developed. An application was properly validated with a high level of sensitivity. A telephone questionnaire helped to clarify the outcomes of capnography use in EDs and ICUs. Convenience of sampling, clearly established goals and the comparison of techniques within the same cardiac context.
Qualitative “A qualitative evaluation of capnography use in paediatric sedation: Perceptions, practice and barriers”. An inductive approach was used to analyze the information. The first step was a review of interview transcripts to gain an overall understanding of the themes, identify emerging topics for discussion, and clarify the connection between different concepts. A grounded theory approach was based on a coding structure with line-by-line transcripts. A comparative method was applied to refine codes and encourage a systematic review. Manual analysis was performed to promote outcome evaluation using HyperRESEARCH version 3.5.2 for defining thematic categories. Inductively generated theories and themes were analyzed until theoretical saturation. As soon as capnography technology was introduced, it could be applied to a variety of patients in different healthcare settings. Interviews helped to test people’s opinions and attitudes towards the chosen technique. Criterion sampling (past participation in randomized controlled trials) and the presence of a team of researchers who reviewed discrepancies and developed consensus-based decisions.
Mixed Methods “Experiences with capnography in acute care settings: A mixed-methods analysis of clinical staff”. First, a grounded theory approach was applied through interactive data analysis and a comparative method where ideas were inductively generated, and theories were built. Then, a coding team worked on interview transcripts line by line. An iterative process occurred to edit themes. HyperRESEARCH qualitative analysis software was used to organize gathered data. Finally, an audit trial was performed to ensure that all systematic documentation was added to the study. This provoked analytical decision-making among the researchers. Cohen’s khelped to control reporting of capnography use. The Fisher exact test was applied to analyze demographic data of participants. Student t test helped to analyze the differences between capnography use and nonuse. Inductive analysis enhanced reliability, and interviews were used to obtain credible information from participants. A purposeful sample contributed to a better discussion of the topic. Physicians and nurses from different departments were invited to participate in semi-structured interviews and share their opinions about future implementation of capnography in their practice.