- Email: [email protected]
THE SWAN-GANZ CATHETER
MONITORING CARDIAC FUNCTION AND TISSUE PERFUSION
0749-0704/96 $0.00
+
.20
THE SWAN-GANZ CATHETER Twenty-five Years of Monitoring Yehuda Ginosar, BSc, MBBS, and Charles L. Sprung, MD
The 25 years that have passed since the introduction of the pulmonary artery catheter (PAC) have been marked by radical changes in the practice of medicine in general and of critical care in particular. There has been an increased application of physiologic principles to the management of shock states, myocardial infarction, and respiratory failure. These years have been marked by the growth of highly sophisticated measurement techniques in clinical medicine. Because of this progress and parallel advances in allied subspecialties, there has been an increase in the expectations of patients and physicians alike and a greater preparedness to offer surgery or critical care to extremely aged or infirm patients. All of these simultaneous developments have impaired the appraisal of the impact of the PAC on outcome in critical care; indeed, the retrospective assessment of the impact of any one advance in such a dynamic field is likely to be, at best, subjective. The prospective assessment of the benefits of pulmonary arterial (PA) catheterization has been hampered by the lack of clinical trials, a consequence of the prevailing faith in the merits of the PAC and the perceived ethical dilemma of randomly "denying" patients PA catheterization.6, This honeymoon period has been long in passing, but, possibly as a consequence of the advance of noninvasive monitoring options, a more critical appraisal of the role of the PAC in current practice is more likely than was possible even 5 years ago.', 4,11, 23 The PAC developed from the extrapolation of the techniques used in the cardiac catheterization laboratory to provide hemodynamic data at the bedside. The principle of a flotation catheter (using the inflated balloon as a sail to be swept along the current of blood flow though the tricuspid and pulmonary valves) avoids the need for imaging techniques to guide catheter placernent.2l "Wedging" the inflated balloon in a proximal pulmonary artery also avoids the
From the Department of Anesthesiology and Critical Care Medicine, Hadassah University Hospital, The Hebrew University of Jerusalem, Jerusalem, Israel
CRITICAL CARE CLINICS VOLUME 12 * NUMBER 4 OCTOBER 1996
771
772
GINOSAR & SPRUNG
need to place the catheter tip in a distal pulmonary artery (with the attendant risks of infarction and trauma). The popularity of the PAC in critical care practice surprised even the team who developed it; they had anticipated its use being restricted to research.21,22 Clinical reports of PAC use, expanding indications, and complications appeared widely in the medical literature shortly after the landmark paper in 1970. Despite the fact that PA catheterization has never been shown clearly to reduce patient mortality, its use for various indications in the critically ill patient became routine Throughout the 1980s, the use of the PAC rose rapidly, resulting in an increase from 400,000 to more than 2 million catheters sold annually worldwide (Baxter Healthcare Corp., personal communication) (Fig. 1). The role of the PAC has expanded in critical care, both in terms of the clinical conditions that provide indications for its use and in terms of the direct and indirect data that may be accumulated.1z An important consequence of the introduction of the PAC into critical care practice was the necessity for the physician to consider physiologic and pathophysiologic concepts in the management plan. This plan allowed the physician to alter selectively the preload or afterload, to construct Starling curves, and to estimate contractility (as the changing cardiac performance under varying physiologic or pharmacologic conditions). In addition, the ability of PA catheterization to determine pressure gradients across the pulmonary circulation enabled the physician to differentiate cardiogenic from noncardiogenic pulmonary edema. Furthermore, based on the assessment of cardiac output and oxygen delivery, the PAC was used to guide the application of fluid and positive endexpiratory pressure (PEEP) in respiratory failure.*,19, 2o The various forms of
- -=
-Standard PAC
+Pacing 2500
PAC
- +-0ximetric &Total
PAC
PACs
2000
8
z
-6
1500
X
3
1000
500
0 1970
1980
Year
1990
Figure 1. Annual worldwide sales of the pulmonary artery catheter (all companies),1970 to 1996. PAC = pulmonary artery catheter. (Data from Baxter Healthcare Corporation, Round Lake, IL.)
THE SWAN-GANZ CATHETER
773
"shock" (cardiogenic, septic, hypovolemic, obstructive) each have distinct hemodynamic profiles and could be diagnosed more easily at the bedside. Pure hemodynamic diagnoses, however, did not always emerge. For example, sepsis may be accompanied by hemorrhage, hypovolemia, and myocardial dysfunction and may be treated with a combination of inotropic and other vasoactive drugs. All of these elements have their own hemodynamic influence, but the cumulative effect is occasionally confusing. The PAC also has been used to assess high-risk patients in the perioperative period, both by correcting abnormal hemodynamic variables and, in some centers, by actively pursuing supranormal ones.17 The PAC also has been used in the perioperative period as an early warning monitor for myocardial ischemia [acute deterioration in myocardial compliance or the appearance of "V" waves in the PA occlusion pressure (PAOP) trace].'O There has been a growing pharmacopoeia in critical care, ranging from classical vasodilators and inotropic agents to nitric oxide. The development and application of these drugs frequently was based on clinical observations made using hemodyanmic monitoring, whereas the rational use of these drugs often requires hemodynamic monitors to direct therapy. Although the first PAC did not allow for the measurement of cardiac output, this was provided for in early modifications by the use of a thermistor located close to the tip of the PAC. Thus, the basic PAC of 25 years ago evolved rapidly from a tool restricted to the measurement of pressures (including the pressure gradient across the pulmonary circulation) to a more sophisticated monitoring device. This evolution allowed (1) the direct measurement of pressures (right atrial, right ventricular, PA, PAOP), cardiac output, and mixed venous blood gas samples and (2) the indirect assessment of hemodynamic calculations that depended on the addition of cardiac output as a measured variable (systemic and pulmonary vascular resistance, left and right ventricular work index, oxygen delivery and consumption, and the intrapulmonary rightto-left shunt). Later versions have allowed cardiac pacing, the continuous assessment of cardiac output and mixed venous oxygen saturation, the measurement of right ventricular ejection fraction (and right ventricular end-diastolic volume), pulmonary capillary pressure, and extravascular lung water. The PAC is also associated with complications. The nature of the adverse effects may be (1)the direct result of central venous access (such as pneumothorax), (2) the direct result of PAC insertion or maintenance (such as ventricular dysrhythmias, pulmonary infarction, or pulmonary artery rupture), or (3) the indireot consequence of the measurement of data using the PAC (such as the initiation of inappropriate therapy as a result of errors in cardiac output or filling pressure determination). From an early prospective study of 500 patients, Boyd et a12 showed that there was a subjective assessment of patient benefit in 8O%, minor complications in 24%, and a serious complication in 4.4% of patients. The catheter could not be directly implicated in any patient death. The incidence of overall complications has been difficult to assess because it depends largely on the experience of the physicians involved and the types of patients selected. In relation to the first of these factors, studies both in the United States9 and in Europe5 among intensive care unit personnel have revealed a depressing lack of familiarity with basic hemodynamic theory and practice among a sizable portion of staff involved with PAC insertion and maintenance. Two features of both studies were a surprisingly low number of PACs inserted or used by each staff member studied and a correlation between the individual's hemodynamic monitoring workload and his or her adequacy of knowledge.
774
GINOSAR & SPRUNG
The rare but occasionally serious complications mandate the use of hemodynamic monitoring within the context of an integrated approach to critical care in which the potential benefits outweigh potential harm and in which maximum use is made of the data available. The most vocal opposition to PA catheterization probably has exaggerated the abuse and misuse of the PAC (and certainly the extent of patient harm caused as a r e s ~ l t ) . ' ~Nevertheless, ,'~ the catheter is not always used appropriately or for maximum patient benefit. It is distressing to see how many patients have PACs placed without full use of the catheter's potential. Cardiac output and mixed venous blood measurements with concomitant hemodynamic calculations are rarely, if ever, performed in some intensive care or coronary care units. The PAC has been demonstrated to provide a more accurate hemodynamic assessment than can be made clinically. Connors et a1,3 in a prospective assessment of 62 patients, showed that fewer than 50% of clinicians correctly predicted PAOP or cardiac output and that 48% made at least one change in treatment based on the data obtained from PA catheterization. In addition, Waller et alZ4 showed that surgeons and anesthesiologists were unaware of problems during 65% of cases of severe hemodynamic abnormalities during coronary bypass when they were blinded to data obtained from the PAC. Rao and El-Etr14 showed a greatly increased perioperative infarction rate among patients who had previous myocardial infarctions. This increase in perioperative infarction rate was greatly reduced if PA catheterization was performed before surgery (an overall reduction from 7.7% to 2.3%, with a reduction from 28% to 5% for an infarct more recent than 6 months). Studies performed by Shoemaker et all7 of high-risk patients undergoing major surgery showed that a treatment group in which PACs were inserted and used to guide the active pursuit of supranormal hemodynamic variables had a lower mortality rate and length of intensive care unit admission than either of two control groups (central venous pressure monitoring only and PAC without active pursuit of supranormal values). These results have not been found in subsequent studies: which may be related to different patient groups or other methodologic variables. Although some question remains as to the applicability of the data to the general patient population, Shoemaker's report stressed the importance of not merely inserting a PAC but also using it actively to pursue physiologic therapeutic goals. There are four key criteria for beneficial hemodynamic monitoring. (1) Appropriate patient selection, in which the consequences of possible complications are outweighed by the potential benefit. Potential benefit depends both on a defined end-point (such as a specific PAOP value for a particular diagnosis) and on the availability of treatment options for detected hemodynamic anomalies. A diagnostic tool could not be expected to reduce mortality without an accompanying therapeutic maneuver.18 (2) Caution should be taken when performing the procedure and when measuring hemodynamic variables so as to minimize the possibility of complications. (3) All hemodynamic data should be extracted (cardiac output and mixed venous gases should be measured and hemodynamic calculations made) so as to maximize the information used. (4) The therapeutic goals specified previously should be pursued actively, and this pursuit should be monitored frequently and regularly by the changing hemodynamic variables obtained from PA catheterization. The PAC has accompanied the coming of age of intensive care medicine and cannot be judged in isolation from the generally increased technical sophistication over the last 25 years. Currently, its use is being assessed in comparison with noninvasive techniques such as transesophageal echocardiography. The
THE SWAN-GANZ CATHETER
775
next 25 years are likely to see a shift in stress from hemodynamic to metabolic monitoring (such as near infrared spectroscopy), but as a simple, albeit invasive, bedside tool for the calculation of necessary hemodynamic variables, the PAC is likely to remain in the intensivist’s arsenal. References 1. American Society of Anesthesiologists Task Force on Pulmonary Artery Catheterization: Practice guidelines for pulmonary artery catheterization. Anesthesiology 78380394, 1993 2. Boyd KD, Thomas SJ, Gold J, et al: A prospective study of complications of pulmonary artery catheters in 500 consecutive patients. Chest 84:245-249, 1983 3. Connors AF Jr, McCaffree DR, Gray BA: Evaluation of right heart catheterization in the critically ill patient without acute myocardial infarction. N Engl J Med 308263267, 1983 4. European Society of Intensive Care Medicine: Expert panel: The use of the pulmonary artery catheter. Intensive Care Med 171-VIII, 1991 5. Gnaegi A, Feihl F, Perret C: Knowledge of intensive care physicians concerning the pulmonary artery catheter. CCM, in press 6. Guyatt G, Ontario Intensive Care Study Group: A randomized control trial of rightheart catheterization in critically ill patients. Journal of Intensive Care Medicine 6:9195, 1991 7. Hayes MA, Timmins AC, Yau EHS, et a1 Elevation of systemic oxygen delivery in the treatment of critically ill patients. N Engl J Med 3301717-1722, 1994 8. Humphrey H, Hall J, Sznaider I, et al: Improved survival in ARDS patients with a reduction in pulmonary capillary wedge pressure. Chest 97117&1180, 1990 9. Iberti TJ, Fischer EP, Leibowitz AB, et al: A multicenter study of physicians’ knowledge of the pulmonary artery catheter. JAMA 264:292&%2932, 1990 10. Kaplan JA, Wells P H Early diagnosis of myocardial ischemia using the pulmonary artery catheter. Anesth Analg 60:789-793, 1981 11. Naylor CD, Sibbald WJ, Sprung CL, et al: Pulmonary artery catheterization: Can there be an integrated strategy for guideline development and research promotion? JAMA 2692407-2411, 1993 12. Phelan JM, Parrillo JE: Indication for pulmonary artery catheterization. In Sprung CL (ed): The Pulmonary Artery Catheter: Methodology and Clinical Applications, ed 2. Closter, NJ, Critical Care Research Associates, 1993, pp 43-76 13. Putterman C, Sprung CL: Technology assessment and the pulmonary artery catheter. In Sprung CL (ed): The Pulmonary Artery Catheter: Methodology and Clinical Applications, ed 2. Closter, NJ, Critical Care Research Associates, 1993, pp 31-42 14. Rao TLK, El-Etr AA: Re-infarction following anesthesia in patients with myocardial infarction. Anesthesiology 59:499-505, 1983 15. Robin ED: Death by pulmonary artery flow-directed catheter: Time for a moratorium? Chest 92727-731, 1987 16. Robin E D Hazards of the Swan Ganz catheter [letter]. Ann Intern Med 108:151, 1988 17. Shoemaker WC, Appel PL, Kram HB, et a1 Prospective trial of supranormal values of survivors as therapeutic goals in high-risk surgical patients. Chest 94:1176-1186, 1988 18. Sibbald WJ, Sprung CL: The pulmonary artery catheter: The debate continues. Chest 94899-901, 1988 19. Simmons RS, Berdine GG, Seidenfeld JJ, et al: Fluid balance and the adult respiratory distress syndrome. Am Rev Respir Dis 1353924-929, 1987 20. Suter PM, Fairley HB, Isenberg MD: Optimum end-expiratory airway pressure in patients with acute pulmonary failure. N Engl J Med 292284289, 1975 21. Swan HJC: Introduction. In Sprung CL (ed): The Pulmonary Artery Catheter: Methodology and Clinical Applications. Rockville, MD, Aspen, 1983, pp 73-104 22. Swan HJC, Ganz W: The Swan Ganz catheter: Past and present. In Blitt CD (ed): Monitoring in Anesthesia and Critical Care Medicine, ed 2. New York, Churchill Livingstone, 1990, pp 211-220
776
GINOSAR & SPRUNG
23. Technology Subcommittee of the Working Group on Critical Care, Ontario Ministry of Health. Hemodynamic monitoring: A technology assessment. Can Med Assoc J 145:114-121, 1991 24. Waller JL, Johnson SP, Kaplan JA, et al: Usefulness of pulmonary artery catheters during aortocoronary bypass surgery. Anesth Analg 61:221-222, 1982 Address reprint requests to Yehuda Ginosar, BSc, MBBS Department of Anesthesiology and Critical Care Medicine Hadassah University Hospital The Hebrew University of Jerusalem POB 12000 Jerusalem 91120, Israel
0749-0704/96 $0.00
+
.20
THE SWAN-GANZ CATHETER Twenty-five Years of Monitoring Yehuda Ginosar, BSc, MBBS, and Charles L. Sprung, MD
The 25 years that have passed since the introduction of the pulmonary artery catheter (PAC) have been marked by radical changes in the practice of medicine in general and of critical care in particular. There has been an increased application of physiologic principles to the management of shock states, myocardial infarction, and respiratory failure. These years have been marked by the growth of highly sophisticated measurement techniques in clinical medicine. Because of this progress and parallel advances in allied subspecialties, there has been an increase in the expectations of patients and physicians alike and a greater preparedness to offer surgery or critical care to extremely aged or infirm patients. All of these simultaneous developments have impaired the appraisal of the impact of the PAC on outcome in critical care; indeed, the retrospective assessment of the impact of any one advance in such a dynamic field is likely to be, at best, subjective. The prospective assessment of the benefits of pulmonary arterial (PA) catheterization has been hampered by the lack of clinical trials, a consequence of the prevailing faith in the merits of the PAC and the perceived ethical dilemma of randomly "denying" patients PA catheterization.6, This honeymoon period has been long in passing, but, possibly as a consequence of the advance of noninvasive monitoring options, a more critical appraisal of the role of the PAC in current practice is more likely than was possible even 5 years ago.', 4,11, 23 The PAC developed from the extrapolation of the techniques used in the cardiac catheterization laboratory to provide hemodynamic data at the bedside. The principle of a flotation catheter (using the inflated balloon as a sail to be swept along the current of blood flow though the tricuspid and pulmonary valves) avoids the need for imaging techniques to guide catheter placernent.2l "Wedging" the inflated balloon in a proximal pulmonary artery also avoids the
From the Department of Anesthesiology and Critical Care Medicine, Hadassah University Hospital, The Hebrew University of Jerusalem, Jerusalem, Israel
CRITICAL CARE CLINICS VOLUME 12 * NUMBER 4 OCTOBER 1996
771
772
GINOSAR & SPRUNG
need to place the catheter tip in a distal pulmonary artery (with the attendant risks of infarction and trauma). The popularity of the PAC in critical care practice surprised even the team who developed it; they had anticipated its use being restricted to research.21,22 Clinical reports of PAC use, expanding indications, and complications appeared widely in the medical literature shortly after the landmark paper in 1970. Despite the fact that PA catheterization has never been shown clearly to reduce patient mortality, its use for various indications in the critically ill patient became routine Throughout the 1980s, the use of the PAC rose rapidly, resulting in an increase from 400,000 to more than 2 million catheters sold annually worldwide (Baxter Healthcare Corp., personal communication) (Fig. 1). The role of the PAC has expanded in critical care, both in terms of the clinical conditions that provide indications for its use and in terms of the direct and indirect data that may be accumulated.1z An important consequence of the introduction of the PAC into critical care practice was the necessity for the physician to consider physiologic and pathophysiologic concepts in the management plan. This plan allowed the physician to alter selectively the preload or afterload, to construct Starling curves, and to estimate contractility (as the changing cardiac performance under varying physiologic or pharmacologic conditions). In addition, the ability of PA catheterization to determine pressure gradients across the pulmonary circulation enabled the physician to differentiate cardiogenic from noncardiogenic pulmonary edema. Furthermore, based on the assessment of cardiac output and oxygen delivery, the PAC was used to guide the application of fluid and positive endexpiratory pressure (PEEP) in respiratory failure.*,19, 2o The various forms of
- -=
-Standard PAC
+Pacing 2500
PAC
- +-0ximetric &Total
PAC
PACs
2000
8
z
-6
1500
X
3
1000
500
0 1970
1980
Year
1990
Figure 1. Annual worldwide sales of the pulmonary artery catheter (all companies),1970 to 1996. PAC = pulmonary artery catheter. (Data from Baxter Healthcare Corporation, Round Lake, IL.)
THE SWAN-GANZ CATHETER
773
"shock" (cardiogenic, septic, hypovolemic, obstructive) each have distinct hemodynamic profiles and could be diagnosed more easily at the bedside. Pure hemodynamic diagnoses, however, did not always emerge. For example, sepsis may be accompanied by hemorrhage, hypovolemia, and myocardial dysfunction and may be treated with a combination of inotropic and other vasoactive drugs. All of these elements have their own hemodynamic influence, but the cumulative effect is occasionally confusing. The PAC also has been used to assess high-risk patients in the perioperative period, both by correcting abnormal hemodynamic variables and, in some centers, by actively pursuing supranormal ones.17 The PAC also has been used in the perioperative period as an early warning monitor for myocardial ischemia [acute deterioration in myocardial compliance or the appearance of "V" waves in the PA occlusion pressure (PAOP) trace].'O There has been a growing pharmacopoeia in critical care, ranging from classical vasodilators and inotropic agents to nitric oxide. The development and application of these drugs frequently was based on clinical observations made using hemodyanmic monitoring, whereas the rational use of these drugs often requires hemodynamic monitors to direct therapy. Although the first PAC did not allow for the measurement of cardiac output, this was provided for in early modifications by the use of a thermistor located close to the tip of the PAC. Thus, the basic PAC of 25 years ago evolved rapidly from a tool restricted to the measurement of pressures (including the pressure gradient across the pulmonary circulation) to a more sophisticated monitoring device. This evolution allowed (1) the direct measurement of pressures (right atrial, right ventricular, PA, PAOP), cardiac output, and mixed venous blood gas samples and (2) the indirect assessment of hemodynamic calculations that depended on the addition of cardiac output as a measured variable (systemic and pulmonary vascular resistance, left and right ventricular work index, oxygen delivery and consumption, and the intrapulmonary rightto-left shunt). Later versions have allowed cardiac pacing, the continuous assessment of cardiac output and mixed venous oxygen saturation, the measurement of right ventricular ejection fraction (and right ventricular end-diastolic volume), pulmonary capillary pressure, and extravascular lung water. The PAC is also associated with complications. The nature of the adverse effects may be (1)the direct result of central venous access (such as pneumothorax), (2) the direct result of PAC insertion or maintenance (such as ventricular dysrhythmias, pulmonary infarction, or pulmonary artery rupture), or (3) the indireot consequence of the measurement of data using the PAC (such as the initiation of inappropriate therapy as a result of errors in cardiac output or filling pressure determination). From an early prospective study of 500 patients, Boyd et a12 showed that there was a subjective assessment of patient benefit in 8O%, minor complications in 24%, and a serious complication in 4.4% of patients. The catheter could not be directly implicated in any patient death. The incidence of overall complications has been difficult to assess because it depends largely on the experience of the physicians involved and the types of patients selected. In relation to the first of these factors, studies both in the United States9 and in Europe5 among intensive care unit personnel have revealed a depressing lack of familiarity with basic hemodynamic theory and practice among a sizable portion of staff involved with PAC insertion and maintenance. Two features of both studies were a surprisingly low number of PACs inserted or used by each staff member studied and a correlation between the individual's hemodynamic monitoring workload and his or her adequacy of knowledge.
774
GINOSAR & SPRUNG
The rare but occasionally serious complications mandate the use of hemodynamic monitoring within the context of an integrated approach to critical care in which the potential benefits outweigh potential harm and in which maximum use is made of the data available. The most vocal opposition to PA catheterization probably has exaggerated the abuse and misuse of the PAC (and certainly the extent of patient harm caused as a r e s ~ l t ) . ' ~Nevertheless, ,'~ the catheter is not always used appropriately or for maximum patient benefit. It is distressing to see how many patients have PACs placed without full use of the catheter's potential. Cardiac output and mixed venous blood measurements with concomitant hemodynamic calculations are rarely, if ever, performed in some intensive care or coronary care units. The PAC has been demonstrated to provide a more accurate hemodynamic assessment than can be made clinically. Connors et a1,3 in a prospective assessment of 62 patients, showed that fewer than 50% of clinicians correctly predicted PAOP or cardiac output and that 48% made at least one change in treatment based on the data obtained from PA catheterization. In addition, Waller et alZ4 showed that surgeons and anesthesiologists were unaware of problems during 65% of cases of severe hemodynamic abnormalities during coronary bypass when they were blinded to data obtained from the PAC. Rao and El-Etr14 showed a greatly increased perioperative infarction rate among patients who had previous myocardial infarctions. This increase in perioperative infarction rate was greatly reduced if PA catheterization was performed before surgery (an overall reduction from 7.7% to 2.3%, with a reduction from 28% to 5% for an infarct more recent than 6 months). Studies performed by Shoemaker et all7 of high-risk patients undergoing major surgery showed that a treatment group in which PACs were inserted and used to guide the active pursuit of supranormal hemodynamic variables had a lower mortality rate and length of intensive care unit admission than either of two control groups (central venous pressure monitoring only and PAC without active pursuit of supranormal values). These results have not been found in subsequent studies: which may be related to different patient groups or other methodologic variables. Although some question remains as to the applicability of the data to the general patient population, Shoemaker's report stressed the importance of not merely inserting a PAC but also using it actively to pursue physiologic therapeutic goals. There are four key criteria for beneficial hemodynamic monitoring. (1) Appropriate patient selection, in which the consequences of possible complications are outweighed by the potential benefit. Potential benefit depends both on a defined end-point (such as a specific PAOP value for a particular diagnosis) and on the availability of treatment options for detected hemodynamic anomalies. A diagnostic tool could not be expected to reduce mortality without an accompanying therapeutic maneuver.18 (2) Caution should be taken when performing the procedure and when measuring hemodynamic variables so as to minimize the possibility of complications. (3) All hemodynamic data should be extracted (cardiac output and mixed venous gases should be measured and hemodynamic calculations made) so as to maximize the information used. (4) The therapeutic goals specified previously should be pursued actively, and this pursuit should be monitored frequently and regularly by the changing hemodynamic variables obtained from PA catheterization. The PAC has accompanied the coming of age of intensive care medicine and cannot be judged in isolation from the generally increased technical sophistication over the last 25 years. Currently, its use is being assessed in comparison with noninvasive techniques such as transesophageal echocardiography. The
THE SWAN-GANZ CATHETER
775
next 25 years are likely to see a shift in stress from hemodynamic to metabolic monitoring (such as near infrared spectroscopy), but as a simple, albeit invasive, bedside tool for the calculation of necessary hemodynamic variables, the PAC is likely to remain in the intensivist’s arsenal. References 1. American Society of Anesthesiologists Task Force on Pulmonary Artery Catheterization: Practice guidelines for pulmonary artery catheterization. Anesthesiology 78380394, 1993 2. Boyd KD, Thomas SJ, Gold J, et al: A prospective study of complications of pulmonary artery catheters in 500 consecutive patients. Chest 84:245-249, 1983 3. Connors AF Jr, McCaffree DR, Gray BA: Evaluation of right heart catheterization in the critically ill patient without acute myocardial infarction. N Engl J Med 308263267, 1983 4. European Society of Intensive Care Medicine: Expert panel: The use of the pulmonary artery catheter. Intensive Care Med 171-VIII, 1991 5. Gnaegi A, Feihl F, Perret C: Knowledge of intensive care physicians concerning the pulmonary artery catheter. CCM, in press 6. Guyatt G, Ontario Intensive Care Study Group: A randomized control trial of rightheart catheterization in critically ill patients. Journal of Intensive Care Medicine 6:9195, 1991 7. Hayes MA, Timmins AC, Yau EHS, et a1 Elevation of systemic oxygen delivery in the treatment of critically ill patients. N Engl J Med 3301717-1722, 1994 8. Humphrey H, Hall J, Sznaider I, et al: Improved survival in ARDS patients with a reduction in pulmonary capillary wedge pressure. Chest 97117&1180, 1990 9. Iberti TJ, Fischer EP, Leibowitz AB, et al: A multicenter study of physicians’ knowledge of the pulmonary artery catheter. JAMA 264:292&%2932, 1990 10. Kaplan JA, Wells P H Early diagnosis of myocardial ischemia using the pulmonary artery catheter. Anesth Analg 60:789-793, 1981 11. Naylor CD, Sibbald WJ, Sprung CL, et al: Pulmonary artery catheterization: Can there be an integrated strategy for guideline development and research promotion? JAMA 2692407-2411, 1993 12. Phelan JM, Parrillo JE: Indication for pulmonary artery catheterization. In Sprung CL (ed): The Pulmonary Artery Catheter: Methodology and Clinical Applications, ed 2. Closter, NJ, Critical Care Research Associates, 1993, pp 43-76 13. Putterman C, Sprung CL: Technology assessment and the pulmonary artery catheter. In Sprung CL (ed): The Pulmonary Artery Catheter: Methodology and Clinical Applications, ed 2. Closter, NJ, Critical Care Research Associates, 1993, pp 31-42 14. Rao TLK, El-Etr AA: Re-infarction following anesthesia in patients with myocardial infarction. Anesthesiology 59:499-505, 1983 15. Robin ED: Death by pulmonary artery flow-directed catheter: Time for a moratorium? Chest 92727-731, 1987 16. Robin E D Hazards of the Swan Ganz catheter [letter]. Ann Intern Med 108:151, 1988 17. Shoemaker WC, Appel PL, Kram HB, et a1 Prospective trial of supranormal values of survivors as therapeutic goals in high-risk surgical patients. Chest 94:1176-1186, 1988 18. Sibbald WJ, Sprung CL: The pulmonary artery catheter: The debate continues. Chest 94899-901, 1988 19. Simmons RS, Berdine GG, Seidenfeld JJ, et al: Fluid balance and the adult respiratory distress syndrome. Am Rev Respir Dis 1353924-929, 1987 20. Suter PM, Fairley HB, Isenberg MD: Optimum end-expiratory airway pressure in patients with acute pulmonary failure. N Engl J Med 292284289, 1975 21. Swan HJC: Introduction. In Sprung CL (ed): The Pulmonary Artery Catheter: Methodology and Clinical Applications. Rockville, MD, Aspen, 1983, pp 73-104 22. Swan HJC, Ganz W: The Swan Ganz catheter: Past and present. In Blitt CD (ed): Monitoring in Anesthesia and Critical Care Medicine, ed 2. New York, Churchill Livingstone, 1990, pp 211-220
776
GINOSAR & SPRUNG
23. Technology Subcommittee of the Working Group on Critical Care, Ontario Ministry of Health. Hemodynamic monitoring: A technology assessment. Can Med Assoc J 145:114-121, 1991 24. Waller JL, Johnson SP, Kaplan JA, et al: Usefulness of pulmonary artery catheters during aortocoronary bypass surgery. Anesth Analg 61:221-222, 1982 Address reprint requests to Yehuda Ginosar, BSc, MBBS Department of Anesthesiology and Critical Care Medicine Hadassah University Hospital The Hebrew University of Jerusalem POB 12000 Jerusalem 91120, Israel