Pulmonary Artery Catheter Utilization: The Use, Misuse, or Abuse
2006; Elsevier BV; Volume: 20; Issue: 3 Linguagem: Inglês
10.1053/j.jvca.2006.03.018
ISSN1532-8422
Autores Tópico(s)Cardiac Arrest and Resuscitation
ResumoFor the past 20 years, articles and editorials have appeared in journals questioning the appropriateness and/or benefit of pulmonary artery catheter (PAC) monitoring. Some have gone so far as to suggest a "moratorium" against the utilization of PACs.1Robin E.D. Death by pulmonary artery flow-directed catheter Time for a moratorium.Chest. 1987; 92: 727-731Crossref PubMed Google Scholar, 2Dalen J.E. Bone R.C. Is it time to pull the pulmonary artery catheter?.JAMA. 1996; 276: 916-918Crossref PubMed Google Scholar A few publicized articles have received significant attention and have prompted many individuals and institutions to re-evaluate their current practices.3Gore J.M. Goldberg R.J. Spodick D.H. et al.A community wide assessment of the use of pulmonary artery catheter in patients with acute myocardial infarction.Chest. 1987; 92: 721-727Crossref PubMed Scopus (295) Google Scholar, 4Connors A.F. Speroff T.S. Davidson N.V. et al.The effectiveness of right heart catheterization in the initial care of critically ill patients.JAMA. 1996; 276: 889-897Crossref PubMed Google Scholar, 5Sandham J.D. Hull R.D. Brant R.F. et al.Canadian Critical Care Trials GroupA randomized controlled trial of the use of pulmonary artery catheters in high-risk surgical patients.N Engl J Med. 2003; 348: 5-14Crossref PubMed Scopus (1194) Google Scholar This past year, several more articles have been published reconfirming the previously reported lack of outcome benefit from PAC use.6Shah M.R. Hasselbled V. Stevenson L.W. et al.Impact of the pulmonary artery catheter in critically ill patients Meta-analysis of randomized clinical trials.JAMA. 2005; 294: 1664-1670Crossref PubMed Scopus (551) Google Scholar, 7The Escape Investigators and Escape Study CoordinatorsEvaluation of congestive heart failure and pulmonary artery catheterization effectiveness.JAMA. 2005; 294: 1625-1633Crossref PubMed Scopus (1034) Google Scholar, 8Harvey S. Harrison D.A. Singer M. et al.Assessment of clinical effectiveness of pulmonary artery catheters in the management of patients in intensive care (PAC-MAN) A randomized trial.Lancet. 2005; 366: 472-477Abstract Full Text Full Text PDF PubMed Scopus (809) Google Scholar In this issue of the Journal, 5 more articles appear addressing the use of the PAC and its impact on patient outcome.9Resano F.G. Kapetanakis E.I. Hill P.C. et al.Clinical outcomes of low-risk patients undergoing beating-heart surgery with or without pulmonary artery catheterization.J Cardiothorac Vasc Anesth. 2006; 20: 300-306Abstract Full Text Full Text PDF PubMed Scopus (40) Google Scholar, 10Djaiani G. Karski J. Yudin M. et al.Clinical outcomes in patients undergoing elective coronary artery bypass graft surgery with and without utilization of pulmonary artery catheter–generated data.J Cardiothorac Vasc Anesth. 2006; 20: 307-310Abstract Full Text Full Text PDF PubMed Scopus (20) Google Scholar, 11Settergren G. Angdin M. Anderson R.E. et al.Wedging the pulmonary artery catheter Changes in left atrial and pulmonary artery pressures and risk of perforation.J Cardiothorac Vasc Anesth. 2006; 20: 311-314Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar, 12Fortin M. Turcotte R. Gleeton O. et al.Catheter-induced pulmonary artery rupture Using occlusion balloon to avoid lung isolation.J Cardiothorac Vasc Anesth. 2006; 20: 376-378Abstract Full Text Full Text PDF PubMed Scopus (10) Google Scholar, 13Jacobsohn E. Fessler D.A. Rosemeier F. et al.Morbidity and mortality associated with accidentally entrapped pulmonary artery catheters during cardiac surgery A case series.J Cardiothorac Vasc Anesth. 2006; 20: 371-375Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar These articles suggest that PAC use may result in patient harm. The mantra of negativism has been heard and it is getting louder; but before abandoning the PAC (or as some have referred to it, the "Swan Gone(z)" catheter), the issues raised in the literature, as well as the proposed alternatives for patient management, must be reassessed. In one article included herein, Resano and colleagues examined clinical outcomes in low-risk patients undergoing beating heart surgery.9Resano F.G. Kapetanakis E.I. Hill P.C. et al.Clinical outcomes of low-risk patients undergoing beating-heart surgery with or without pulmonary artery catheterization.J Cardiothorac Vasc Anesth. 2006; 20: 300-306Abstract Full Text Full Text PDF PubMed Scopus (40) Google Scholar Similar to previous studies, this retrospective, nonrandomized analysis did not demonstrate a significant mortality difference, but did show a significant increased utilization of inotropic agents and a prolonged intensive care unit (ICU) stay in the PAC group. Like other low-risk patient analyses, this study appears grossly underpowered to draw conclusions regarding a mortality difference.5Sandham J.D. Hull R.D. Brant R.F. et al.Canadian Critical Care Trials GroupA randomized controlled trial of the use of pulmonary artery catheters in high-risk surgical patients.N Engl J Med. 2003; 348: 5-14Crossref PubMed Scopus (1194) Google Scholar, 14Bellomo R. Uchino S. Cardiovascular monitoring tools Use and misuse.Curr Opin Crit Care. 2003; 9: 225-229Crossref PubMed Scopus (61) Google Scholar In another trial, Djaiani and colleagues performed a prospective observational study assessing the need for PAC-generated data in the management of low-risk patients undergoing elective coronary artery bypass graft surgery.10Djaiani G. Karski J. Yudin M. et al.Clinical outcomes in patients undergoing elective coronary artery bypass graft surgery with and without utilization of pulmonary artery catheter–generated data.J Cardiothorac Vasc Anesth. 2006; 20: 307-310Abstract Full Text Full Text PDF PubMed Scopus (20) Google Scholar Although the intent was to blind PAC data from the caregivers, they were not blinded from the monitor's pulmonary artery tracing. The authors concluded the employment of a PAC "could be delayed until the clinical need arises." Interestingly, despite the routine use of central venous pressure (CVP) monitoring, they elected to unblind the PAC data in 23% of patients, resulting in a treatment modification in 9%. It can be suspected that the inference of their conclusions was that these numbers are small and clinically insignificant. To the contrary, these numbers could be considered high for a low-risk population with predicted low mortality (0.0% in this study). The additional 3 articles by Settergren et al,11Settergren G. Angdin M. Anderson R.E. et al.Wedging the pulmonary artery catheter Changes in left atrial and pulmonary artery pressures and risk of perforation.J Cardiothorac Vasc Anesth. 2006; 20: 311-314Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar Fortin et al,12Fortin M. Turcotte R. Gleeton O. et al.Catheter-induced pulmonary artery rupture Using occlusion balloon to avoid lung isolation.J Cardiothorac Vasc Anesth. 2006; 20: 376-378Abstract Full Text Full Text PDF PubMed Scopus (10) Google Scholar and Jacobsohn et al13Jacobsohn E. Fessler D.A. Rosemeier F. et al.Morbidity and mortality associated with accidentally entrapped pulmonary artery catheters during cardiac surgery A case series.J Cardiothorac Vasc Anesth. 2006; 20: 371-375Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar discuss 2 recognized complications associated with PAC use, as well as their proposed mechanisms and management (discussed later). On the basis of these new articles and the prior available literature, how can clinicians rationally assess and justify PAC utilization in the future? Before beginning any defense of the PAC, this author must concur and support the opinion that the routine use of PACs in low-risk patients is probably unwarranted. No technology or diagnostic modality should be employed inappropriately, excessively, indiscriminately, and without a demonstration of benefit. It is this author's contention that clinicians' greatest issues are not with the PAC, but with their understanding and utilization of this technology. Before inadvisably condemning the PAC, the following questions should be answered: What should be expected from a monitoring or diagnostic device? Does it accurately measure what it is intended to measure within acceptable clinical limits? Does it provide data for clinical decision-making? How should the technology be assessed independently or against proposed alternative methods? What should be concluded from the available knowledge on this topic? The PAC is a monitoring/diagnostic tool and should not be expected to independently alter outcomes! To that regard, there is an absence of scientific studies demonstrating a conclusive mortality benefit from other commonly employed or endorsed monitoring technologies (eg, pulse oximetry [SaO2], transesophageal echocardiography [TEE], CVP). Numerous studies have repetitively demonstrated flaws in judgment predicated on the clinical examination in critically ill patients in the absence of diagnostic tools.15Eisenberg P. Jaffe A. Shuster D. Clinical evaluation compared to pulmonary artery catheterization in the hemodynamic assessment of critically ill patients.Crit Care Med. 1984; 12: 549-553Crossref PubMed Scopus (313) Google Scholar, 16Squara P. Bennett D. Perret C. Pulmonary artery catheters. Does the problem lie in the user?.Chest. 2002; 121: 2009-2015Crossref PubMed Scopus (59) Google Scholar, 17Steingrub J.S. Celoria G. Vickers-Lahti M. et al.Therapeutic impact of pulmonary artery catheterization in a medical/surgical ICU.Chest. 1991; 99: 1451-1455Crossref PubMed Scopus (78) Google Scholar The PAC provides data—cardiac output, intrapulmonary vascular pressures, mixed venous oxygen saturation (SvO2), ejection fraction, and end-diastolic volume numbers. The conversion of these diagnostic data to knowledge can potentially impact outcome through the appropriate and timely delivery of care. But numbers don't cure patients! Therapeutics (eg, antibiotics, antihypertensives, thrombolytics, etc) alter outcome. The defense of the PAC has been predicated on the scientific quality of the existing studies. The specific methodologic flaws cited are many—selection bias; retrospective design; inadequate blinding or randomization; crossover; underpowered for conclusion offered; "funny" statistics; therapeutic trespass of protocols without independent justification; caregiver noncompliance; Hawthorne effect; or questionable goals or endpoints of care. As a result of the above issues, many clinicians (the present author included) have commonly employed "expert opinion" as the basis for the practice and "evidence-based" care for the PAC. The clinician should not pass judgment based on studies of low-risk patients anymore than he or she can interpret the independent role, risk, or benefit of PAC use in studies of patients in which the mortality grossly exceeds the projected APACHE II projected risk of death.5Sandham J.D. Hull R.D. Brant R.F. et al.Canadian Critical Care Trials GroupA randomized controlled trial of the use of pulmonary artery catheters in high-risk surgical patients.N Engl J Med. 2003; 348: 5-14Crossref PubMed Scopus (1194) Google Scholar, 8Harvey S. Harrison D.A. Singer M. et al.Assessment of clinical effectiveness of pulmonary artery catheters in the management of patients in intensive care (PAC-MAN) A randomized trial.Lancet. 2005; 366: 472-477Abstract Full Text Full Text PDF PubMed Scopus (809) Google Scholar The basis for a PAC (monitoring) benefit should be predicated on enhanced availability of diagnostic data, altering the subsequent patient management, resulting in an improved outcome (morbidity and mortality). Unquestionably, the PAC provides more data on a continuous basis than are available from a CVP. Unfortunately, there is a recognized and continued demonstration of inadequate caregiver knowledge or competency in the use of PACs and the management of critically ill patients.18Iberti T. Fischer E. Leibowitz A. et al.A multicenter study of physician knowledge of the pulmonary artery catheter.JAMA. 1990; 12: 2933-2940Google Scholar, 19Gnaegi A. Feihl F. Perret C. Intensive care physicians insufficient knowledge of right heart catheterization at the bedside Time to act.Crit Care Med. 1997; 25: 213-220Crossref PubMed Scopus (223) Google Scholar, 20Trottier S.J. Taylor R.W. Physicians' attitudes toward and knowledge of the pulmonary artery catheter Society of Critical Care Medicine membership survey.New Horiz. 1997; 5: 201-206PubMed Google Scholar, 21Jacka M. Cohen M.M. To T. et al.PAOP estimation—how confident are anesthesiologists.Crit Care Med. 2002; 30: 1197-1203Crossref PubMed Scopus (40) Google Scholar These gaps in knowledge can lead to the misinterpretation of the data, as well as the delivery of inappropriate or unwarranted therapeutic interventions.22Pinsky M.R. Vincent J.L. Let us use the pulmonary artery catheter correctly and only when we need it.Crit Care Med. 2005; 33: 1119-1122Crossref PubMed Scopus (138) Google Scholar Squara and colleagues questioned the role of the PAC user (rather than the PAC) in a study to determine the impact of PAC data on treatment variability and appropriateness of care by critical care physicians versus the opinion of a panel of experts in the management of a clinical case.16Squara P. Bennett D. Perret C. Pulmonary artery catheters. Does the problem lie in the user?.Chest. 2002; 121: 2009-2015Crossref PubMed Scopus (59) Google Scholar Their results showed that PAC data reduced the variability of therapeutic interventions, improved agreement among participants as well as between the participant and experts, and reduced the incidence of "harmful" (therapeutic trespass) treatments. The persistent frequency (10%) of harmful therapies suggested the need for further practitioner training. Their conclusions provide reason for concern for the injudicious abandonment of PAC utilization in the care of critically ill patients under appropriate circumstances by trained individuals. It is this author's belief that the problems regarding PAC utilization are several-fold: (1) inaccurate measurement and data interpretation; (2) inappropriate, unwarranted, or scientifically unsubstantiated therapeutic interventions and protocols; (3) delays in the timeliness of intervention; (4) inappropriate patient selection; and (5) the absence of a treatment to alter the outcome of the underlying pathophysiologic condition. The absence of a treatment protocol speaks to the question of variability of care, yet the provision of a protocol does not assure the independent benefit or appropriateness of each treatment decision in the care and management of the individual patient or situation. The initiation of a treatment (protocol) based on monitoring can be a harm or benefit. Therefore, the demonstrated increased use of inotropes in association with the use of PAC data is not necessarily justified nor the fault of the PAC.5Sandham J.D. Hull R.D. Brant R.F. et al.Canadian Critical Care Trials GroupA randomized controlled trial of the use of pulmonary artery catheters in high-risk surgical patients.N Engl J Med. 2003; 348: 5-14Crossref PubMed Scopus (1194) Google Scholar, 9Resano F.G. Kapetanakis E.I. Hill P.C. et al.Clinical outcomes of low-risk patients undergoing beating-heart surgery with or without pulmonary artery catheterization.J Cardiothorac Vasc Anesth. 2006; 20: 300-306Abstract Full Text Full Text PDF PubMed Scopus (40) Google Scholar A recent protocol for the management of severe sepsis and septic shock (early goal-directed therapy) demonstrated a 16% reduction in "absolute" mortality.23Rivers E. Bryant N. Haystall S. et al.Early goal-directed therapy in the treatment of severe sepsis and septic shock.N Engl J Med. 2001; 345: 1368-1377Crossref PubMed Scopus (7927) Google Scholar Looking at the individual elements and goals of the protocol (fluids, pressors, lactate level, central venous oxygen saturation [ScvO2] monitoring, CVP endpoints, dobutamine, or transfusion therapy), all could be discussed and independently questioned for validity and value to the outcome. What appears to be significant between the goal-directed protocol and control groups relative to outcome are the acuity of intervention and time to therapy. Timeliness of care has been previously demonstrated to impact outcome in multiple situations related to critical care. Myocardial ischemia/infarction; cerebrovascular ischemia/stroke; trauma; antibiotic administration for pneumonia; and now sepsis all appear to have a window of time that directly impacts efficacy of care and outcome. How often are diagnostic or therapeutic interventions delayed in critically ill patients for a period of "wait and see?" Clinicians have experienced the role of pulse oximetry and capnography in the early detection of oxygenation or ventilation abnormalities. The data provided or abnormality detected by the monitors does not assure appropriate patient assessment or management (that is clinician-dependent). Timeliness of PAC utilization has been addressed in a number of articles. In a study by Lefrant and colleagues, the median time to PAC insertion was 120 minutes from the point of decision to employ a PAC, but the common time delay from the initial period of patient need or reversible deterioration was not addressed.24Lefrant J.Y. Muller L. Bruelle P. et al.Insertion time of the pulmonary artery catheter in critically ill patients.Crit Care Med. 2000; 28: 355-359Crossref PubMed Scopus (33) Google Scholar Others have shown an outcome benefit utilizing a PAC in the preoperative "normalization" of hemodynamics in patients undergoing major elective noncardiac surgery.25Flanebaum L. Ziegler D. Choban P.S. Preoperative intensive care unit admission and hemodynamic monitoring in patients scheduled for major elective noncardiac surgery A retrospective review of 95 patients.J Cardiothorac Vasc Anesth. 1998; 12: 3-9Abstract Full Text PDF Scopus (34) Google Scholar Based on experience with pulse oximetry and capnography, it appears intuitively evident that appropriate diagnostics, coupled with the effective timely administration of therapeutic interventions, could result in better outcomes under the right circumstances. As for the commonly recommended role of alternative diagnostics, most would agree that less is better. Presuming adequate knowledge and training by the user, what is the basis to support CVP and ScvO2 measurements having a mortality outcome benefit, but pulmonary artery occlusion pressure (PAOP) and SvO2 not being beneficial? Why would cardiac output measured by any other technology result in better quality data or outcome than thermodilution cardiac output from a PAC? With the understanding that the role and definition of the word monitor are to "warn or remind," why would it be accepted or presumed that the measurement of an intermittent number would be better than the availability of continuous data in the dynamic and unstable critically ill patient? What about the recent inference that TEE is the technology of choice, especially for intraoperative use during cardiac surgery? Proponents argue (and this author tends to agree) that it is less invasive and provides better data as it relates to cardiac anatomy, preload, ischemia detection, and cardiac function. Despite many articles suggesting the value and encouraging the use of TEE in the anesthetic and surgical management of the cardiac surgical patient, there is a lack of evidence supporting its routine use and "… essentially no randomized trials assessing health outcomes for diagnostic tests," such as echocardiography.26Cheitlin M.D. Armstrong W.F. Aogemma G.P. et al.ACC/AHA/ASE 2003 guidelines update for the clinical application of echocardiography.Circulation. 2003; 108: 1146-1162Crossref PubMed Scopus (683) Google Scholar Evidence suggests a definite lack of uniform training and knowledge base in personnel using TEE, and an undefined role for its application in the prolonged management of the nonintraoperative (ie, ICU) critically ill patient. TEE is very operator-dependent. Similar to the PAC (or other technologies), "the inaccurate interpretation of TEE images by inexperienced examiners can generate incorrect information, potentially resulting in improper clinical decisions … hence unnecessary perioperative complications."27Practice guidelines for perioperative transesophageal echocardiography. A report by the ASA and SCA Task Force in Transesophageal Echocardiography.Anesthesiology. 1996; 84: 986-1006Crossref PubMed Scopus (520) Google Scholar, 28Stevenson J.G. Adherence to physician training guidelines for pediatric transesophageal echocardiography affects the outcome of patients undergoing repair of congenital cardiac defects.J Am Soc Echocardiog. 1999; 12: 165-172Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar While TEE appears to be an excellent addition to the technologic armamentarium, it seems to be supported primarily by "recommendations based on evidence from observational studies or on the expert consensus," causing concern about the appropriate application.27Practice guidelines for perioperative transesophageal echocardiography. A report by the ASA and SCA Task Force in Transesophageal Echocardiography.Anesthesiology. 1996; 84: 986-1006Crossref PubMed Scopus (520) Google Scholar Seems like an old story that has been heard before! The other 3 articles in this issue are consistent with many other reports expressing concern about the procedural risks associated with PAC monitoring.11Settergren G. Angdin M. Anderson R.E. et al.Wedging the pulmonary artery catheter Changes in left atrial and pulmonary artery pressures and risk of perforation.J Cardiothorac Vasc Anesth. 2006; 20: 311-314Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar, 12Fortin M. Turcotte R. Gleeton O. et al.Catheter-induced pulmonary artery rupture Using occlusion balloon to avoid lung isolation.J Cardiothorac Vasc Anesth. 2006; 20: 376-378Abstract Full Text Full Text PDF PubMed Scopus (10) Google Scholar, 13Jacobsohn E. Fessler D.A. Rosemeier F. et al.Morbidity and mortality associated with accidentally entrapped pulmonary artery catheters during cardiac surgery A case series.J Cardiothorac Vasc Anesth. 2006; 20: 371-375Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar Yes, it is true that most invasive procedures have associated risks and complications! Yes, unnecessary procedures are unwarranted! Yes, the unknowing or inexperienced will not benefit from the information, and potentially generate additional and avoidable complications associated with the procedure itself or the interpretation of the data.18Iberti T. Fischer E. Leibowitz A. et al.A multicenter study of physician knowledge of the pulmonary artery catheter.JAMA. 1990; 12: 2933-2940Google Scholar, 36Deshpande K.S. Hatem C. Ulrich H.L. et al.The incidence of infectious complications of central venous catheters at the subclavian, internal jugular, and femoral sites in an intensive care unit population.Crit Care Med. 2005; 33: 13-20Crossref PubMed Scopus (176) Google Scholar The simple acceptance of a CVP as the monitoring surrogate for the PAC (despite less data generation) does not eliminate one of the most frequent complications associated with the PAC, that of central venous cannulation.29McGee D.C. Gould M.K. Current concepts preventing complications of central venous monitoring.N Engl J Med. 2003; 348: 1123-1133Crossref PubMed Scopus (1638) Google Scholar Yes, there is the very rare but recognized complication of PA perforation; yet there is also the rare but reported complication of cardiac tamponade associated with CVP monitoring.30Collier P.C. Blocker S.H. Graff D.M. et al.Cardiac tamponade from central venous catheters.Am J Surg. 1998; 176: 212-214Abstract Full Text Full Text PDF PubMed Scopus (139) Google Scholar When an institution's frequency of a complication appears to exceed the recognized published incidence, it must presume underreporting by others or an institutional need to address the problem. Only through training and experience can the skills necessary to assess the situation, appreciate the relative risks associated with the procedure, and, most importantly, benefit from the information obtained in an effort to alter the management and patient outcome be attained. TEE is touted for both the information generated and perceived safety. Despite its classification as minimally invasive, the frequency of certain complications like dysphagia are reportedly high and significant complications like esophageal perforation (and associated death) have been previously recognized.31Brinkman W.T. Shanewise J.B. Clements S.D. et al.Transesophageal echocardiography Not an innocuous procedure.Ann Thorac Surg. 2001; 72: 1725-1726Abstract Full Text Full Text PDF PubMed Scopus (20) Google Scholar, 32Rousou J.A. Tighe D.A. Garb J.L. et al.Risk of dysphagia after transesophageal echocardiography during cardiac operations.Ann Thorac Surg. 2000; 69 (discussion 489-490): 486-489Abstract Full Text Full Text PDF PubMed Scopus (99) Google Scholar A recent retrospective database audit at a single institution was aimed at determining the incidence of major gastrointestinal (GI) complications associated with intraoperative TEE for cardiac surgery.33Lennon M.J. Gibbs N.M. Weightman W.M. et al.Transesophageal echocardiography—related gastrointestinal complications in cardiac surgical patients.J Cardiothorac Vasc Anesth. 2005; 19: 141-145Abstract Full Text Full Text PDF PubMed Scopus (126) Google Scholar The authors' results suggested a 4-fold increase in major complications, defined as perforation of the esophagus or stomach and upper GI bleeding requiring transfusion. The 1.2% incidence was greater than previously reported because of their inclusion of late presentations (>24 hours post-procedure), suggesting a potential underestimation by others. With the addition of the 5 articles included herein to the continued assault on the PAC, where do clinicans go from here? What has been learned from the literature? What should clinicians do? It is now universally agreed that the PAC is not indicated for all routine cardiac surgical procedures. The intraoperative period is a limited and often controlled environment relative to the perioperative period. If the PAC is going to make a difference it will be in the perioperative care of the critically ill patient with reversible pathophysiology, when additional data enhance clinical decision-making to guide therapeutic interventions. The PAC is probably unnecessary in the low-risk patient and unwarranted in the terminally moribund patient. The complexity and responsibility associated with the care of critically ill patients are continually challenging. In the pursuit of excellence, clinicians need to develop problem-solving skills that go beyond basic pattern recognition and limited understanding, generating a high risk of error and therapeutic misadventure. The uniqueness of individual patient management must be appreciated, despite the desire to implement goal-directed, protocol-based therapies. Expert knowledge necessitates a programatic analysis, utilizing multiple variables, differentiating several pathophysiologic alternatives, predicated on prior experiences and applicable to the specific problem and individual.34Norman G.R. Problem-solving skills, solving problems, and problem-based learning.Med Education. 1988; 22: 279-286Crossref PubMed Scopus (193) Google Scholar Caution should be taken against the unbridled enthusiasm for any technology used by the untrained or inexperienced—even if it is noninvasive. Individuals who have not demonstrated a reasonable understanding of the key issues associated with a diagnostic or therapeutic approach cannot be credentialed. The biggest problem continues to be the inappropriate measurement and interpretation of the data, leading to inappropriate and potentially harmful interventions (eg, atropine is not the cornerstone therapy for hypoxemic-induced bradycardia). With respect to the preceding discussion, if clinicians are going to employ PACs, it must be for the appropriate patient and clinical situation, and in the appropriate setting.35Practice guidelines for pulmonary artery catheterization. An updated report by the American Society of Anesthesiologists Task Force on Pulmonary Artery Catheterization.Anesthesiology. 2003; 99: 998-1014Google Scholar Patient selection is the first step. The patient should not be low risk. The patient should be one with significant pre-existent disease at risk of further organ dysfunction or death. The situation should be predicated on the individual's risk of acute pathophysiologic pertubations associated with the clinical problem or surgical procedure, in which the additional diagnostic data can guide the therapeutic decisions. Probably the most important (and often underappreciated) impact on the benefit and/or risk associated with PAC monitoring is the setting. Just inserting the catheter or implementing a protocol will not be enough to make a real difference in the high-risk critically ill patient. All caregivers (eg, nurses, physician's assistants, nurse practitioners) involved in the management of these patients must be educated to appropriately assess the information generated, appreciate the changes or trends identified, and recognize the potential limitations or mishaps associated with the use of PACs. Nursing education and participation are essential for the provision of continuous care (24/7) in the critically ill. Online web-based programs are being developed to improve the knowledge base on the PAC and the management of hemodynamic issues. There is no free lunch. Today, the focus is on the PAC. Irrespective of this author's opinions or bias, clinicians must put the responsibility where it rightfully belongs. It should not be presumed that the practice of PAC monitoring or the role of any diagnostic approach will independently alter outcome. Remember, numbers do not cure patients! The role of the practitioner must be addressed. History has implied that it is more often the carpenter and not the tools. Over the past 3 decades, the PAC has enhanced the clinician's ability to assess the cardiopulmonary system, understand the response to therapeutic interventions, and advance the art of managing critically ill patients. As a long-term advocate of the PAC, this author is concerned that the correct questions have not been asked nor answered by well-conducted and appropriate studies. If that is the case, the fear is that the universal extrapolation of the available data could compromise the use of the PAC for the appropriate patient, in the appropriate situation, and appropriate setting. Clinicians must continue the pursuit of education and knowledge. The diagnostic acumen must be enhanced as new and better therapeutics are developed to guide the timely institution for the given individual. Clinicians should not "throw the baby out with the bath water" while attempting to address the real problems—the practice of PAC monitoring or the practitioners of care!
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