Use of the pulmonary artery catheter to reduce operative complications

Pulmonary artery catheters for adult patients in intensive care

BACKGROUND

Since pulmonary artery balloon flotation catheterization was first introduced in 1970, by HJ Swan and W Ganz, it has been widely disseminated as a diagnostic tool without rigorous evaluation of its clinical utility and effectiveness in critically ill patients. A pulmonary artery catheter (PAC) is inserted through a central venous access into the right side of the heart and floated into the pulmonary artery. PAC is used to measure stroke volume, cardiac output, mixed venous oxygen saturation and intracardiac pressures with a variety of additional calculated variables to guide diagnosis and treatment. Complications of the procedure are mainly related to line insertion. Relatively uncommon complications include cardiac arrhythmias, pulmonary haemorrhage and infarct, and associated mortality from balloon tip rupture.

OBJECTIVES

To provide an up-to-date assessment of the effectiveness of a PAC on mortality, length of stay (LOS) in intensive care unit (ICU) and hospital and cost of care in adult intensive care patients.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 12); MEDLINE (1954 to January 2012); EMBASE (1980 to January 2012); CINAHL (1982 to January 2012), and reference lists of articles. We contacted researchers in the field. We did a grey literature search for articles published until January 2012.

SELECTION CRITERIA

We included all randomized controlled trials conducted in adults ICUs, comparing management with and without a PAC.

DATA COLLECTION AND ANALYSIS

We screened the titles and abstracts and then the full text reports identified from our electronic search. Two authors (SR and MG) independently reviewed the titles, abstracts and then the full text reports for inclusion. We determined the final list of included studies by discussion among the group members (SR, ND, MG, AK and SC) with consensus agreement. We included all the studies that were in the original review. We assessed seven domains of potential risk of bias for the included studies. We examined the clinical, methodological and statistical heterogeneity and used random-effects model for meta-analysis. We calculated risk ratio for mortality across studies and mean days for LOS.

MAIN RESULTS

We included 13 studies (5686 patients). We judged blinding of participants and personnel and blinding of outcome assessment to be at high risk in about 50% of the included studies and at low risk in 25% to 30% of the studies. Regardless of the high risk of performance bias these studies were included based on the low weight the studies had in the meta-analysis. We rated 75% of the studies as low risk for selection, attrition and reporting bias. All 13 studies reported some type of hospital mortality (28-day, 30-day, 60-day or ICU mortality). We considered studies of high-risk surgery patients (eight studies) and general intensive care patients (five studies) separately as subgroups for meta-analysis. The pooled risk ratio (RR) for mortality for the studies of general intensive care patients was 1.02 (95% confidence interval (CI) 0.96 to 1.09) and for the studies of high-risk surgery patients the RR was 0.98 (95% CI 0.74 to 1.29). Of the eight studies of high-risk surgery patients, five evaluated the effectiveness of pre-operative optimization but there was no difference in mortality when these studies were examined separately. PAC did not affect general ICU LOS (reported by four studies) or hospital LOS (reported by nine studies). Four studies, conducted in the United States (US), reported costs based on hospital charges billed, which on average were higher in the PAC groups. Two of these studies qualified for analysis and did not show a statistically significant hospital cost difference (mean difference USD 900, 95% CI -2620 to 4420, P = 0.62).

AUTHORS' CONCLUSIONS

PAC is a diagnostic and haemodynamic monitoring tool but not a therapeutic intervention. Our review concluded that use of a PAC did not alter the mortality, general ICU or hospital LOS, or cost for adult patients in intensive care. The quality of evidence was high for mortality and LOS but low for cost analysis. Efficacy studies are needed to determine if there are optimal PAC-guided management protocols, which when applied to specific patient groups in ICUs could result in benefits such as shock reversal, improved organ function and less vasopressor use. Newer, less-invasive haemodynamic monitoring tools need to be validated against PAC prior to clinical use in critically ill patients.

Intraoperative Peripherally Inserted Central Venous Catheter Central Venous Pressure Monitoring in Abdominal Aortic Aneurysm Reconstruction

Numerous studies have found no clinically significant benefit to the perioperative use of pulmonary artery catheters (PACs), and peripherally inserted central venous catheters (PICCs) have been reported to measure central venous pressure (CVP) accurately. The objective of this study was to determine whether the dynamic shifts in preload associated with elective reconstruction of abdominal aortic aneurysms (AAAs) are accurately reflected by CVP measurements from open-ended PICCs compared to CVP measurements from concomitant indwelling PACs. This is a retrospective review of prospectively collected data. PICCs and PACs were placed preoperatively in five patients undergoing elective AAA reconstruction. CVP measurements were recorded every 15 min during the operation. Bland-Altman statistical analysis was used to determine the degree of agreement in data collected by the two measurement devices. Seventy-three paired measurements of CVP from concomitant indwelling PICCs and PACs obtained from five patients undergoing elective AAA reconstruction revealed PICC measurements to be higher than PAC measurements by 0.6 mm Hg (overall correlation coefficient 0.92). The difference between the two measurement devices was expected to be <3.4 mm Hg at least 95% of the time. The findings of this pilot study indicate that PICCs are an effective method for CVP monitoring in situations of dynamic systemic compliance and preload, such as those observed during elective AAA reconstruction.

Pulmonary artery catheters for adult patients in intensive care

BACKGROUND

Pulmonary artery catheterization was adopted about 30 years ago and widely disseminated without rigorous evaluation as to whether it benefited critically ill patients. The technique is used to measure cardiac output and pressures in the pulmonary circulation to guide diagnosis and treatment. Clinicians believe these data can improve patients' outcomes, even in the absence of consensus about the specific interpretation of the data.

OBJECTIVES

To assess the effect of pulmonary artery catheterization on mortality and cost of care in adult intensive care patients.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2, 2006); MEDLINE (all records to April 2006); EMBASE (all records to April 2006); CINAHL (all records to April 2006) and reference lists of articles. We contacted manufacturers and researchers in the field.

SELECTION CRITERIA

We included all randomized controlled trials in adults, comparing management with and without a pulmonary artery catheter (PAC).

DATA COLLECTION AND ANALYSIS

We screened the titles and abstracts of the electronic search results and obtained the full text of studies of possible relevance for independent review. We determined the final results of the literature search by consensus between the authors. We did not contact study authors for additional information.

MAIN RESULTS

We identified 12 studies. Mortality was reported as hospital, 28-day, 30-day, or intensive care unit. We considered studies of high-risk surgery patients (eight studies) and general intensive care patients (four studies) separately for the meta-analysis. The pooled odds ratio for the studies of general intensive care patients was 1.05 (95% confidence interval (CI) 0.87 to 1.26) and for the studies of high-risk surgery patients 0.99 (95% CI 0.73 to 1.24). Of the eight studies of high-risk surgery patients, five evaluated the effectiveness of pre-operative optimization but there was no difference in mortality when these studies were examined separately. Pulmonary artery catheterization did not affect intensive care unit (reported by 10 studies) or hospital (reported by nine studies) length of stay. Four studies, conducted in the United States, measured costs based on hospital charges billed to patients, which on average were higher in the PAC groups.

AUTHORS' CONCLUSIONS

To date, there have been two multi-centre trials of the effectiveness of PACs for managing critically ill patients admitted to intensive care, although only one was adequately powered. Efficacy studies are needed to determine optimal management protocols and patient groups who could benefit from management with a PAC.

Partial CO2 rebreathing indirect Fick technique for non-invasive measurement of cardiac output

OBJECTIVE

Evaluation in animals of a non-invasive and continuous cardiac output monitoring system based on partial carbon-dioxide (CO2) rebreathing indirect Fick technique.

METHODS

We have developed a non-invasive cardiac output (NICO) monitoring system, based on the partial rebreathing method. The partial rebreathing technique employs a differential form of the Fick equation for calculating cardiac output (QT) using non-invasive measurements. Changes in CO2 elimination (deltaVCO2) and partial pressure of end-tidal CO2 (deltaPETCO2) in response to a brief period of partial rebreathing are used to measure pulmonary capillary blood flow (Q(PCBF)). A non-invasive estimate of anatomic and intrapulmonary shunt fraction (Q(S)/Q(T)), based on oxygen saturation from pulse oximetry (SpO2) and inspired oxygen concentration (FIO2), is added to compute total cardiac output [Q(T) = Q(PCBF)/(1 - Q(S)/Q(T))]. The performance of the NICO was compared with iced 5% dextrose bolus thermodilution cardiac output (TDco) measurements in 6 dogs. Cardiac output was varied using dobutamine, and halothane, and by clamping of the inferior vena cava. Two hundred and forty-six (n = 246) paired measurements of TDco and NICO over a range of cardiac outputs (TDco range = 0.60-8.87 l/min) were compared using Bland-Altman analysis and weighted correlation coefficient.

RESULTS

The Bland-Altman technique yielded a NICO precision of +/- 0.70 l/min (13.8%) with a mean bias of -0.07 l/min (-1.4%) compared to TDco. The weighted correlation coefficient between TDco and NICO values was: r = 0.93 (n = 246).

CONCLUSION

The partial CO2 rebreathing technique for measurement of cardiac output is non-invasive, automated, and based on the well accepted Fick principle. The limits of agreement between NICO and TDco is within the recommended value for NICO to be a clinically acceptable method for cardiac output measurement. The results of this canine study show that NICO performed as well, and in some cases better, than other currently available non-invasive cardiac output techniques over a wide range of cardiac outputs.

Recognition and management of preoperative risk

Internists are frequently asked to do preoperative consultations and to manage perioperative complications. Realistic goals are to identify patient factors that increase the risk of surgery, to quantify this risk in order to make decisions about the appropriateness of and timing of the surgery, to provide recommendations on how to minimize the risk, to identify and manage coexisting medical conditions and their associated medication requirements, to monitor the patient for perioperative problems, and to make recommendations to deal with these problems when they occur. With few exceptions, nonselective imaging and laboratory screening tests have repeatedly been shown to be of little value when the history and physical do not suggest a problem. The risk associated with the planned surgery can be estimated, with the most common serious complications being cardiac events. Updated versions of Goldman's risk indices are particularly helpful for this. Clinical variables are optimally combined with selective stress testing to discern which patients will benefit from preoperative revascularization. This has been studied best in the setting of vascular surgery. A critical guiding principle is that the value of revascularization must be judged in terms of long term gains rather than just immediate perioperative benefit. Other interventions include the selective use of beta blockers, adequate analgesia for all, control of hypertension, and appropriate volume management, especially in the settings of preexisting CHF or valvular disease. It must also be recognized that perioperative ischemia and CHF often present atypically. An approach that combines aspects of both the ACC/AHA and the ACP guidelines seems optimal. A variety of noncardiac issues must also be addressed. Postoperative pulmonary complications are common, especially with preexisting pulmonary disease, thoracic and upper abdominal surgery, and obesity. PFTs and ABGs are indicated in selected patients. Stopping smoking, incentive spirometry, and selective use of bronchodilators and antibiotics are helpful. Patients with rheumatologic diseases have specific concerns based on systemic manifestations of disease including anemia, thrombocytopenia, pulmonary fibrosis, pericarditis, and hypercoagulability; medication effects particularly from steroids and nonsteroidal anti-inflammatory drugs; and specific joint problems including contractures and atlantoaxial joint instability. Diabetes increases the risk of infection and cardiac complications. Prevention of ketoacidosis and glucose control are necessary and can be achieved through a variety of approaches, depending on whether the patient suffers from Type 1 or Type 2 diabetes. The threshold for transfusion has increased in recent years, as has the use of erythropoietin and autologous blood donation. There is no longer an absolute hemoglobin that requires transfusion, although most require transfusion for hemoglobins less than 8 mg/dL, especially in the setting of cardiac disease and bloody surgery. The elderly require surgery at an increased rate and often do not do as well as younger patients. The primary issues are, however, not their age but their increased frequency of underlying disease and diminished reserve. The latter makes them prone to postoperative delirium, sensitivity to medications, and cardiac and pulmonary problems. Despite the many diseases that patients often have and the stresses of surgery itself, modern anesthetic and surgical techniques allow almost all patients to undergo necessary procedures at acceptable risk. The internist plays a critical role in minimizing this risk even further.

Preoperative intensive care unit admission and hemodynamic monitoring in patients scheduled for major elective noncardiac surgery: a retrospective review of 95 patients

OBJECTIVE

To review experience with preoperative intensive care unit (ICU) admission and hemodynamic monitoring to determine which patients benefited and how.

DESIGN

Retrospective review over 32-month period (1991 to 1994).

SETTING

Surgical ICU of a university teaching hospital.

PARTICIPANTS

Ninety-five patients admitted to the surgical ICU before a major elective noncardiac, nonthoracic surgical procedure.

INTERVENTIONS

All patients underwent hemodynamic monitoring with a pulmonary artery catheter (PAC). Interventions were made at the discretion of the ICU attending and attending surgeon, based on a general algorithm. Patients were categorized based on history or hemodynamics. The historic classification was as follows: group I, patients with cardiac disease documented by history and cardiac imaging, n = 37; group II, patients with cardiac disease documented by history, but not cardiac imaging, n = 24; group III, patients without documented cardiac disease, but with other significant medical problems, n = 34. Hemodynamic classification considered patients to have subnormal parameters if the cardiac index was < 2.5 L/min/m2, the mixed venous oxygen saturation was < 65%, or the oxygen delivery index was < 350 mL/min/m2 (n = 45), and normal parameters if greater than these (n = 50).

MAIN RESULTS

There were no differences in APACHE II scores. Group I patients had greater Goldman Cardiac Risk Indices than group III patients (7.4 +/- 4.8 v 5.0 +/- 3.0). Patients in group I had a significantly greater incidence of subnormal initial hemodynamic values (63%) than patients in group II (47%) or group III (32%). The incidence of postoperative cardiovascular complications among groups was not different. Fifty patients (52%) had normal hemodynamics initially; two (4%) developed postoperative cardiovascular complications compared with 10 patients (22%) of the 45 with subnormal initial hemodynamic values. Of these 45 patients, 24 (52%) had their hemodynamic parameters corrected preoperatively with crystalloids, packed red blood cells, inotropes, and/or afterload reduction. Two of these 24 patients (8%) experienced postoperative cardiovascular complications, compared with 8 of the remaining 21 patients who had no attempt to normalize their hemodynamic values preoperatively other than maintaining a normal pulmonary artery occlusion pressure.

CONCLUSIONS

Patients who had normal initial preoperative hemodynamic parameters or abnormal initial parameters that were normalized preoperatively experienced significantly fewer perioperative cardiovascular complications than those with abnormal initial values that were not normalized preoperatively. These results suggest that there may be benefit to the practice of preoperative ICU admission, hemodynamic monitoring with a PAC, and "optimization" of cardiac function in selected patients undergoing major elective noncardiac surgery. Further studies are needed to better delineate the most appropriate patient populations and effective therapeutic protocol.

Routine pulmonary artery catheterization does not reduce morbidity and mortality of elective vascular surgery: results of a prospective, randomized trial

OBJECTIVE

The authors determined whether the preoperative placement of a pulmonary artery catheter (PAC) with optimization of hemodynamics results in outcome improvement after elective vascular surgery.

SUMMARY BACKGROUND DATA

The PAC commonly is used not only in patients who are critically ill, but also perioperatively in major elective surgery. Few prospective studies exist documenting its usefulness.

METHODS

One hundred four consecutive patients were randomized to have a PAC placed the morning of operation (group I) or to have a PAC placed only if clinically indicated (group II). Group I patients were resuscitated to preestablished endpoints before surgery and kept at these points both intraoperatively and postoperatively. Group II patients received standard care.

RESULTS

There was one death in each group. An intraoperative or postoperative complication developed in 13 patients in group I versus 7 patients in group II (p = not significant). Group I patients received more fluid than did group II patients (5137 +/- 315 mL vs. 3789 +/- 306 mL; p < 0.003). There was no significant difference in either overall or surgical intensive care unit length of stay. Only one patient in group II required a postoperative PAC.

CONCLUSIONS

Routine PAC use in elective vascular surgery increases the volume of fluid given to patients without demonstrable improvement in morbidity or mortality.

A prospective randomized trial of preoperative "optimization" of cardiac function in patients undergoing elective peripheral vascular surgery

BACKGROUND

Previous investigations have suggested that preoperative invasive hemodynamic monitoring with "optimization" of cardiovascular function may favorably affect the outcome among patients undergoing peripheral vascular surgery. The purpose of this study was to evaluate the effect of preoperative optimization of hemodynamic parameters on outcome in patients undergoing aortic reconstruction (AR) or limb salvage procedures (LSP) in a randomized, prospective clinical trial.

METHODS

All 72 patients who consented to participate in this study were admitted to the intensive care unit at least 12 hours before operation for placement of a pulmonary artery catheter (PAC). Patients who were randomized to the treatment group (n = 32) were "optimized" by adjusting their hemoglobin concentration, oxygen saturation (SaO2), cardiac output, or afterload until the mixed venous O2 saturation (SvO2) was at least 65%. The control group (n = 40) underwent placement of a PAC and had oxygen transport parameters measured without any attempt to optimize SvO2.

RESULTS

There were no significant differences between the treatment and control groups with respect to age, gender, type of operation, initial Acute Physiology and Chronic Health Evaluation (APACHE) II score, SvO2, pulmonary artery occlusion pressure, or cardiac index. All treatment patients achieved an SvO2 of at least 65% before operation. Comparing the treatment and control groups, postoperative cardiovascular complications occurred in 25% versus 27%, intraoperative complications in 28% versus 20%, and death in 9% versus 5%, respectively. None of these differences was statistically significant as a whole or within the subgroups undergoing AR or LSP.

CONCLUSIONS

These data suggest that preoperative optimization of cardiovascular function by using achievement of SvO2 above 65% as the end point does not result in any reduction of intraoperative or perioperative cardiac complications in patients undergoing PVS. Further studies with alternative assessments and manipulation of different cardiopulmonary parameters may yield additional information.