The Significance Of The Pulmonary Artery Catheter In Cardiac Surgery - Essay Example

?THE SIGNIFICANCE OF THE PULMONARY ARTERY CATHETER IN CARDIAC SURGERY: AN INSIGHTFUL REVIEW Introduction The utilization of a Pulmonary Artery Catheter in cardiac surgeries has always stirred up controversy; hence, researches were looked into to unravel this generated dilemma. Two articles namely, Do we need a Pulmonary Artery Catheter in Cardiac Anesthesia?-An Indian Perspective (Kanchi 2011) and The Appropriateness of the Pulmonary Artery Catheter in Cardiovascular Surgery (Jacka et al 2002), tackled this pressing matter through conscientious investigation. According to Kanchi (2011), the pulmonary artery catheter is one of the most important and popular advances in the field of cardiac anaesthesia and intensive care; it measures the systolic, diastolic, mean pulmonary artery and the pulmonary capillary occlusion pressures and provides a means to derive many hemodynamic and oxygenation variables. Conversely, Jacka et al (2002) emphasized that the pulmonary artery catheter has the ability to acquire a large amount of physiologic data that aids in reducing uncertainty, facilitate diagnosis and in some cases, to direct interventions. The aforementioned articles were chosen in particular for the reason that, it both facilitated a profound analysis regarding the use of the pulmonary artery catheter in cardiac surgeries. Literature Review and Critique The article entitled, Do we need a Pulmonary Artery Catheter in Cardiac Anesthesia?-An Indian Perspective (Kanchi 2011) explored several important reasons why a pulmonary artery catheter is necessary during cardiac surgeries. Pulmonary artery catheterization or Swan-Ganz catheterization is an important technique for monitoring perioperative and postoperative cardiac pressures during open heart surgery (Kaplan et al 2000). This article clearly cited several reasons deemed important by the author why a pulmonary artery catheter should be utilized during cardiac surgeries. To begin with, Kanchi (2011) stressed that a patient undergoing cardiac surgery has an underlying cardiac pathology which can have an effect on intra-cardiac pressures and myocardial ability to maintain sufficient cardiac output. Moreover, it presents quantifiable information on heart chamber pressure, blood flow and vascular resistance—comparable to the data obtained in a cardiac catheterization laboratory. Secondly, there is a lack of correlation between central venous pressure and left-sided filling pressures in patients with moderate-to-severe cardio-pulmonary diseases; hence, it is rather common to observe a significant change in pulmonary capillary wedge pressure or PCWP with no reflection in central venous pressure or CVP (Kanchi 2011). Thirdly, Kanchi (2011) added that a pulmonary artery catheter offers access to obtain various hemodynamic and oxygen delivery parameters, which are of vital importance in a high-risk cardiac surgical patient. Lastly, the control of perioperative hemodynamic profile with the use of cardiovascular drugs, which affect the myocardial contractility and induce pulmonary and systemic vasodilatation/constriction, mandate the use of a PAC for comprehensive management (Kanchi 2011). As stressed also by Chatterjee (2009), individuals in the medical field have learned a great deal with hemodynamics especially in critically ill patients by employing the use of balloon flotation catheters; thus, its importance should not be neglected or overlooked. Furthermore, Stover et al (2009) highlighted that non-invasive cardiac output and blood pressure monitoring and less invasive devices for Goal-Directed Therapy or GDT cited by Della Rocca and Pompei (2011) in their article, cannot replace invasive monitoring system such as pulmonary artery catheters in examining critically ill patients, for the reason that it is clearly less reliable than the invasive methods. The research article by Kanchi (2011) evidently aims to provide comprehensive guidelines and to clearly identify the possible indications of utilizing a pulmonary artery catheter; hence, this research conducted a survey among the practicing cardiac anaesthesiologists however, the said research obviously mentioned that it was only carried out in the major cardiac centres in India. The author employed the use of a variety of sources even dating back to 1980, which probably for some readers studying the research article would say that the references were already obsolete since the article was published this year 2011. In spite of this, the author just wanted to point out the differences on the utilization of the pulmonary catheter. Furthermore, using a variety of sources from different timelines just goes to show that the author wishes to compare how definition, methods and outcomes affecting utilization of pulmonary artery catheter has changed throughout the years. Moreover, Kanchi (2011) was able not only the indications for using a pulmonary catheter but also the author was able to unravel several probable complications that affected the minimal use of the pulmonary artery catheter in a variety of cardiac surgical procedures. Such complications enumerated were arrhythmia or dysrhythmias specifically non-sustained ventricular tachycardia cited by Baldwin (2000) in his research as experienced evidently by 2% of individuals who underwent removal of pulmonary artery catheter, other potential problems included were coiling/knotting which was also tackled by Bossert et al (2006), surgeon’s stitch, carotid puncture similar to what the findings of the study of Kaczmarek et al (2003) had shown with a total of 71 cases revealed in the results of the said research; results also unravelled that difficult floatation, thrombocytopenia, wedge infarct and intrapulmonary bleeding were also evident complications of using a pulmonary artery catheter. The set of questions applied by Kanchi (2011) to elicit response regarding the use of pulmonary artery catheter among one hundred cardiac anaesthesiologists with at least 5 years of experience in a moderate-to-large sized cardiac surgical set-up where at least 500 cardiac operations happen annually, were objective and comprehensible in attempting to answer the inquiry highlighted by his research. The questions used tried to explore the kinds of pulmonary artery catheter utilized by each cardiac anaesthesiologists while performing cardiac surgeries in their respective facilities whether in the private corporate ones or in the academic institutions. The formulated questions also deemed to correlate known theories cited by the references to actual application via what is practiced and what is experienced by the said respondents. Kanchi (2011) utilized a survey questionnaire to be able to obtain information regarding his research. The author visibly explained how the process of eliciting data was achieved. Kanchi (2011) stated that he got the approval first from the Institutional Review Board (IRB) and then got a census of cardiac anaesthesiologists with at least 5 years of experience in a moderate-to-large-sized cardiac surgical setup. Subsequently, Kanchi (2011) obviously cited that one hundred cardiac anaesthesiologists were selected for his study. The method chosen by the researcher had been effective enough in drawing out information regarding the use of pulmonary artery catheters in cardiac operations. However, the researcher did not mention any advantages or disadvantages of the method he preferred to use. Kanchi (2011) visibly explained the procedure on how data collection was facilitated. The first questionnaire was sent to the respondents in December 2008. Those who did not reply by February 2009 were contacted on telephone to persuade response, and second or final telephonic call was made in March 2009 to obtain a response from the practitioners who did not respond. Kanchi (2011) appropriately analyzed the data obtained using simple descriptive statistics by entering the answers to each question into a database. In addition, the numbers of complications with the use of pulmonary artery catheter were combined to provide complication rate in terms of the number of complications per 1000 pulmonary artery catheterizations. The study undertaken by Kanchi (2011) is more of a qualitative research wherein to be able to analyze the data he obtained; he utilized simple descriptive statistics by entering information into an electronic database which was responsible in scrutinizing the information he acquired. The researcher, however, did not mention how he validated the responses he obtained. The researcher of this study was able to uphold moral principles in conducting his investigation by getting the approval of the Institutional Review Board first before pursuing with the distribution of his survey questionnaires. Moreover, Kanchi (2011) did not mention any particular names in his study probably to maintain the anonymity of his respondents and to promote also the confidentiality of their responses. The results presented by Kanchi (2011) were practitioner-based and included individual preferences in a specific institution. The researcher presented the common complications with the use of a pulmonary artery catheter experienced by the respondents using a table. The results of his study showed that the respondents felt that the pulmonary artery catheter is complementary but not competitive; however, if the clinical situation necessitates its use, the respondents are willing to utilize it. The findings of the result were tackled and backed up by employing a variety of references. Kanchi (2011) highlighted that two previous systematic reviews that analyzed small randomized clinical trials showed no overall benefit of use of a pulmonary artery catheter. Kanchi (2011) also mentioned a prospective cohort study by Connors et al (1996) that involved a mixed population of medical and surgical patients in intensive care units showed increased mortality, length of stay and costs associated with the use of a pulmonary artery catheter. On the contrary, the findings of the study of Shah et al (2005) concluded that the use of the pulmonary artery catheter or PAC neither increased overall mortality or days in hospital nor conferred benefit. Significant problems with PAC study outcomes were also discussed by Kanchi (2011) such as flaw in study design in the form of lack of therapeutic protocols, treatment algorithms and inadequate randomization, insufficient statistical power, lack of competency in interpreting PAC-derived data, some studies left the management decisions at the discretion of treating clinicians, eligibility criteria had tendency to focus on patients that were critically ill but not on patients in whom invasive hemodynamic monitoring was thought of particular value, most studies included patients who were 65 years and older, studies were conducted on heterogeneous population, 9 studies have reported about cross-over, e.g. assignment to the control group but received PAC; nevertheless, because of deteriorating status—with significant monitoring in these patients, subgroups analysis difficult as the number of available studies in all meta-analyses was too small to perform. Based on the findings derived by Kanchi (2011), he recommended the use of a pulmonary artery catheter for the following indications like coronary artery bypass grafting or CABG with decreased left ventricular function, combined procedures, left ventricular aneurysmectomy, recent myocardial infarction that occurred for less than 30 days, renal dysfunction, pulmonary hypertension, diastolic dysfunction, acute ventricular septal defect, and those with left ventricular assist device. The researcher also stressed that to avoid possible complications with the use of pulmonary artery catheter; the institution should have a specific policy regarding its correct use and its correct need in terms of economic considerations, patient population, and the expertise of medical and nursing staff. This is also what Ranucci (2006) stressed in his study that adequate training as to the pathophysiological meaning of this monitoring and diagnostic tool should be given and periodically refreshed so that all of the potential benefits of the PAC can be realized while avoiding potential misuse. Finally, due to the results and recommendations unleashed in the study, the Indian Association of cardiovascular and thoracic anaesthesiologists was motivated in bringing out the guidelines for the practitioners about the use of PAC in cardiac surgery. The other article entitled, The Appropriateness of the Pulmonary Artery Catheter in Cardiovascular Surgery (Jacka et al 2002) described the current clinical practice attitudes among anaesthesiologists in cardiac and vascular surgery during that year in an effort to determine the most appropriate indications for the use of the pulmonary artery catheter or PAC. The researchers pointed out that despite the common use of the pulmonary artery catheter, controversy about its application continues, because of inconsistent and inadequate evidence. At least two organizations namely, the American Society of Anaesthesiologists and the Society of Critical Care Medicine have developed guidelines for pulmonary artery catheter application though these have been limited by broad generalizations. Moreover, clinicians have had to rely on low levels of evidence, and incorporate their own experience, to guide PAC application. The researchers’ goal in conducting this investigation was to ascertain the indications for appropriate PAC application during cardiovascular surgery, as identified by the opinion and typical methodology of practicing anaesthesiologists. In addition, the factors related to the patient, practitioner, and practice setting that may manipulate assessment of appropriateness were also focused on. Jacka et al (2002) also hypothesized that the ratings of appropriateness by practicing clinicians would be associated to patient disease, and to clinicians’ volume and type of practice, amount and level of training, continuing medical education (CME) indicators, and country of certification, training and practice. Jacka et al (2002) utilized several resources even dating back to the year 1970; possibly the authors employed such references from different timelines to provide comparison. However, it would be better if the researchers utilized a more current dated source for the reason that what might be practiced before may not be applicable during the year they conducted the study. The researchers, though, were able to correlate their investigation to a broader aspect by using varied references. The researchers opted to give definition to the word appropriate, the adjective they utilized in their study to describe the incidences or answer the inquiry regarding when the use of pulmonary artery catheter can be maximized. Jacka et al (2002) plainly cited that they use a survey instrument to be able to draw out the data that they wish to obtain to be able to answer their premise. The researchers asked their respondents to rate the appropriateness of pulmonary artery catheter use in thirty-six clinical scenarios by using a nine-point Likert scale. The researchers visibly mentioned that anaesthesiologists from the USA and Canada were the respondents of their study. Jacka et al (2002) stated that they chose respondents specifically from English-speaking hospitals in Canada while subjects from the USA were randomly chosen. The researchers revealed that three hundred forty-five anaesthesiologists at twenty-nine centres were surveyed. The survey instrument was mailed by the researchers on January 13, 1998. Each was numbered and contained a return postcard and self-addressed, stamped with a return envelope. A second mailing was performed to non-respondents one month later. Those still not responding were given a follow-up telephone call, and another mailing if requested (Jacka et al 2002). A second and final telephone call was done in the latter part of April 1998 by the researchers. The responses obtained from the survey instruments were entered into a database using EpiInfo, a public domain Software by the Centre for Disease Control in Atlanta, Georgia and analyzed using SAS version 6.0 by the SAS Institute in the USA (Jacka et al 2002). The respondents’ ratings of appropriateness of PAC use were extracted from the nine-point Likert scale utilized in each of the 36 scenarios. The frequency distributions were scrutinized graphically, and were illustrated using measures of central tendency (mean, mode) and spread (standard error). Respondents were educated on the survey instrument that responses would be grouped as follows: inappropriate (rating 1–3), uncertain appropriateness (rating 4–6), and appropriate (rating 7–9). Initially, the sample size consisted of three hundred forty-seven anaesthesiologists in the twenty-nine centres surveyed. However, two of the respondents moved to another location prior to mailing so they were deleted from the final sample leaving a total of three hundred forty-five subjects. The study by Jacka et al (2002) is evidently a quantitative research. Univariable analyses to evaluate appropriateness ratings with practitioner and practice characteristics were carried out using analysis of variance for categorical and constant variables; whereas, multivariable analysis was consequently executed in a reverse step-wise fashion (Jacka et al 2002). The researchers stressed that all practitioner and practice variables that had a “P” value less than 0.30 or which were clinically sensible were considered in the multivariable analysis. The researchers also cited that the multivariable model was reduced until all remaining variables had a P value less than 0.05. The frequency distributions of all appropriateness ratings were considered prior to univariable and multivariable analyses, to assess the goodness of fit of the linear, logarithmic, and logistic models (Jacka et al 2002). In each case, the best fit was obtained with the logistic model as pointed out by Jacka et al (2002). Consequently, logistic regression was employed by Jacka et al (2002) to gauge the connection between appropriateness ratings of PAC use and the independent variables. Jacka et al (2002) secured an Institutional Ethics approval first before conducting a survey of all anaesthesiologists from all English-speaking hospitals in Canada and in the USA. The researchers preserved the inscrutability of their respondents by not including any particular names in the study so as to also uphold the confidentiality of their responses. The results were presented by Jacka et al (2002) using bar graphs to clearly portray the comparison among the respondents’ answers. According to Wall et al (2002), pulmonary artery catheters are often used during and after coronary bypass grafting. The results of the study conducted by Jacka et al (2002) showed that a majority of the anaesthesiologists agreed that the pulmonary artery catheter was not appropriate with patients with stable angina and normal ventricular function undergoing elective coronary artery bypass grafting or abdominal vascular surgery. When presented with most of the other scenarios, the opinion of anaesthesiologists about PAC appropriateness was uncertain. These situations included distant myocardial infarction or MI, non-surgical aortic stenosis, renal insufficiency not requiring dialysis, renal failure requiring dialysis, recent MI, pulmonary hypertension, and a history of heart failure. However, the respondents agreed that the PAC was appropriate in the patient with a recent exacerbation of heart failure (Jacka et al 2002). Moreover, majority of the respondents agreed that in cases such as impaired ventricular function and stable angina, unstable angina with normal ventricles, unstable angina and ventricular impairment, the utilization of a pulmonary artery catheter was deemed appropriate by the subjects. There were differences in the mean appropriateness scores according to respondent characteristics (Jacka et al 2002). The findings derived from the investigation of Jacka et al (2002) revealed that PAC use during cardiac surgery had a higher appropriateness than its use in vascular practice. On the contrary, in academic practice, the appropriateness was higher than in community practice (Jacka et al 2002). PAC use by Canadian respondents was rated more appropriate than by US respondents according to the results. In the multivariable analyses, the most significant associations were the positive ones between appropriateness and the proportion of cases in which the PAC was used, as well as with the amount of practice (Jacka et al 2002). Furthermore, the country of practice was highly associated with a rating of appropriateness, as those practising in Canada rated PAC appropriateness more highly than those practising in the USA (Jacka et al 2002). Jacka et al (2002) concluded that the appropriate application of the PAC remains unresolved, due to the absence of unequivocal evidence of benefit or harm. Jacka et al (2002) also pointed out that the ideal method to guide clinical practice remains elusive because of patient variation, entrenched practice patterns, financial, and temporal and other logistic constraints. The respondents of the study performed by Jacka et al (2002) also agreed that the use of the PAC in the routine patient without co-morbidity undergoing these surgeries is not appropriate. In multiple other scenarios, no agreement was found among respondents. Hence, the researchers supposed that further use of this method to describe appropriate technology application may be beneficial. Both articles deliberated on the possible incidences or cases where a pulmonary artery catheter might be deemed useful. The study by Kanchi focused mainly on the medical practice only in India while the study by Jacka et al focused on two regions namely, the United States of America and Canada. However, Kanchi’s research is more up to date compared to the study by Jacka et al for the reason that it was published this year 2011 while the latter was made available during the year 2002. Nevertheless, the analysis done by Jacka et al was more complicated and comprehensive than those with Kanchi. Moreover, the research of Jacka et al can be considered as more representative of the population due to a higher number of respondents encouraged to partake in the study. Conclusion Pulmonary artery catheterization is mostly used to define the mechanism of circulatory failure and to optimize patient management (Payen and Gayat 2006). It also allows measurement of hemodynamic variables that cannot be measured reliably or continuously by less invasive means (Evans et al 2009). Moreover, pulmonary artery catheterization with the use of balloon flotation catheters is an easy and rapid technique for bedside hemodynamic monitoring (Chatterjee 2009). Both articles by Kanchi (2011) and Jacka et al (2002) provided substantial evidences regarding the utilization of pulmonary artery catheter during cardiac surgeries. In terms of being timely and content-wise, the study by Kanchi (2011) surpasses that of Jacka et al (2002) for the reason that the research by Kanchi was published this year 2011 and it covered not only the possible indications of pulmonary artery catheter use which was also focused on by Jacka et al, but it also tackled the possible complications associated with the utilization of a pulmonary artery catheter during cardiac surgeries. However, in terms of reliability and complexity, the research done by Jacka et al outshine the study by Kanchi due to the fact that they were able to cover a wider area and were successful in obtaining response from a greater number of subjects. Generally, both articles had their strengths and weaknesses plus each exceeded the other in different aspects so it goes to show that both articles are exceptional in their own ways. References Baldwin, I.C. and Heland, M. 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Available from: < http://www.biomedcentral.com/1471-2253/9/6>. [Accessed 24 October 2011]. Wall, M.H., MacGregor, D.A., Kennedy, D.J., James, R.L., Butterworth, J., Mallak, K.F., and Royster, R.L. (2002) Pulmonary Artery Catheter Placement for Elective Coronary Artery Bypass Grafting: Before or After Anesthetic Induction?. Anesthesia & Analgesia, 94, p. 1409-15. Read More