Increased pulmonary artery perforating potential of pulmonary artery catheters during hypothermia

The rate of major complications from the use of pulmonary artery (PA) catheters has been reported to be as high as 9%, 0.2% of which may be attributed to PA perforation, a catastrophe with a fatal outcome more than 50% of the time. Although an uncommon event generally, more than one third of catheter-related PA perforations occur during cardiac surgery. Several factors act to advance the balloon-tipped PA catheter into the distal PA, where, during hypothermia, the catheter hardens and, thus, may be more likely to perforate the vessel. The relative contribution of hypothermia, itself, to the perforating potential of previously used, triple-lumen PA catheters (n = 5) was examined in vitro by mounting them in a temperature-controlled testing chamber, at a 90 degrees incident angle to a polyethylene membrane, which represented the PA wall. The membrane was made to pulsate 80 times/min against the PA catheter until it was perforated. Each catheter was tested 5 times each at 3 temperatures. At 35 degrees C, 30 degrees C, and 25 degrees C, the number of pulsations to produce perforation (perforation rate) was 488 +/- 280, 309 +/- 242, and 97 +/- 234, respectively. The perforation rates differed significantly between temperatures (P less than 0.01), but not between catheters or tests at the same temperature. This study demonstrates that perforation of a model PA by a triple-lumen PA catheter is 500% more likely during hypothermia.     

Pathophysiology of rupture of the pulmonary artery by pulmonary artery balloon-tipped catheters

High pressures have been reported in pulmonary artery catheter balloons. This study was undertaken to determine the in vitro rupturing pressures of human peripheral pulmonary arteries and to evaluate whether such pressures could be generated under clinical conditions. The in vitro model then was confirmed in vivo in the dog and the evolution of a rupture of a peripheral pulmonary artery studied. In vitro, pulmonary arteries of subjects under age 60 yr are remarkably resistant and tolerate intra-balloon pressures of 2700 mm Hg in the one mid-pulmonary artery studied and up to 4219 +/- 720 mm Hg (mean +/- SD) in the distal pulmonary artery. Subjects over the age of 60 yr have significantly lower rupturing pressures (1965 +/- 540 mm Hg in the mid-pulmonary artery, and 2498 +/- 600 mm Hg in the distal pulmonary artery), (P less than 0.05). Thus overdistension by the balloon may explain most ruptures. Preexisting pulmonary hypertension did not affect in vitro rupturing pressures. Clinicians generated intraballoon mean pressures of 795 +/- 130 mm Hg, with 20% of them generating higher and potentially dangerous pressures (1000 mm Hg or more). The in vitro model was confirmed by in vivo studies in dogs with pressures that cause pulmonary artery rupture. Furthermore, in normal dogs, rupture of a peripheral pulmonary artery was without complications. This suggests that rupture of the peripheral pulmonary artery may occur clinically more frequently than reported. The user of flotation pulmonary arterial catheters should be aware of the dangers associated with this diagnostic tool. In particular, liquids must never be used to inflate pulmonary arterial catheter balloons.     

简易肺动脉导管在心脏直视术后的临床应用

目的通过术中置放简易肺动脉导管（PACs,硬膜外留置管）进行肺动脉压和混合静脉压氧饱和度（SvO2）监测,观察其在术后监测的作用。方法对52例心脏直视术后,并行简易肺动脉导管监测的病人临床资料进行回顾性分析。结果21例病人有不同程度的肺动脉高压（PAP）,12例患者肺动脉舒张压（DPAP）偏低,13例患者DPAP升高,9例患者SvO2低于50％。予以相应处理后．上述参数有所改善。结论心脏直视术后简易肺动脉导管监测可以有效指导临床处理,提高心脏直视术后的监测处理水平。     

Effectiveness of pulmonary artery catheters in aortic surgery: A randomized trial

Purpose: To evaluate the routine use of pulmonary artery catheters (PAC) in patients who undergo aortic surgery. Methods: One hundred twenty patients were randomized to placement of PACs for perioperative monitoring and hemodynamic optimization (tune up) in the intensive care unit on the night before aortic operation, or to intravenous hydration in the ward and perioperative monitoring without PACs. Before randomization, all patients underwent routine adenosine thallium-201 scintigraphy. Results: To meet predetermined endpoints, 30 PAC patients (50%) received nitrates, inotropic agents, or both. PAC patients received more fluid in the preoperative period (p < 0.001) and in the first 24 hours after operation (p = 0.002) than control subjects. Eleven PAC patients (18%) and three control subjects (5%) had adverse intraoperative events (p = 0.02). There were 20 adverse postoperative events in 15 PAC patients (25%; nine cardiac, seven pulmonary, four acute tubular necrosis), which was not different compared with 11 postoperative events in 10 control subjects (17%; five cardiac, five pulmonary, one acute tubular necrosis). There were also no differences in duration of mechanical ventilation, intensive care unit stay, or hospital stay between groups. Postoperative cardiac complications were more common among patients who had a history of congestive heart failure (p = 0.02; odds ratio, 3.75; confidence interval, 1.3 to 11) or reperfusion defects on adenosine thallium scintigraphy (p = 0.01; odds ratio, 3.4; confidence interval, 1.2 to 9.4), regardless of group. Conclusions: Routine use of PACs for perioperative monitoring with the above protocol during aortic surgery is not beneficial and may be associated with a higher rate of intraoperative complications. Preoperative tune up does not prevent postoperative cardiac, renal, and other complications. Variables such as cardiac risk factors and adenosine thallium scintigraphy may be more important predictors of cardiac events in patients who undergo aortic operations. (J Vasc Surg 1998;27:203-12.)     

Safety of a guidewire technique for replacement of pulmonary artery catheters

The purpose of this study was to determine if a guidewire change from a pulmonary artery catheter (PAC) to a central venous catheter (CVC) poses a significant infection risk. A total of 128 consecutive cardiac surgical patients with PACs inserted in the operating room were entered into this study. Postoperatively, patients were randomly allocated to receive a double-lumen CVC, either at the initial introducer insertion site over a guidewire, or at a new site with de novo catheterization. The tips of all introducers, PACs, and CVCs were cut off, cultured, and semi-quantitatively analyzed. The results show that insertion of CVCs over a guidewire within 48 hours after initial venapuncture is no more likely to be associated with catheter colonization than is de novo percutaneous insertion at a different site. From 48 hours up to 72 hours following initial insertion of the PAC, an incidence of catheter-related infection of 35.3% was observed in the guidewire group, as opposed to 12.5% in the de novo group. It is recommended that the use of a guidewire technique for catheter replacement (PAC to CVC) is a safe alternative to de novo insertion of a CVC within 48 hours after initial insertion of the PAC. In order to minimize the potential risk of catheter-related infection and bacteremia in cardiac surgical patients, de novo catheterization beyond 48 hours after initial venapuncture is suggested.     

Introducers and protective sleeves may increase thrombogenicity of pulmonary artery catheters

OBJECTIVE: To investigate the cause of clot formation on the surface of non-heparin coated/bonded pulmonary artery catheters. DESIGN: A controlled, unblinded, open-labeled study. SETTING: Research laboratory at Tulane School of Medicine, New Orleans, LA. PARTICIPANTS: Rhesus and African Green monkeys. INTERVENTIONS: Anesthetized monkeys (n = 24) were assigned to one of two groups. The first group (group A) had a pulmonary artery catheter inserted into a femoral vein through a cutdown without passage through an introducer or protective sleeve before insertion. In the second group (group B), the pulmonary artery catheter was passed through an introducer and protective sleeve before insertion in the femoral vein. After the study, the animals were returned to the primate breeding colony. Laboratory values were measured for each animal, and electron micrographs were taken of selected pulmonary artery catheters before and after passage of these catheters through the introducer sheath and/or protective sleeve. MEASUREMENTS AND MAIN RESULTS: Between the two groups, there was a significant difference in fibrinogen level, but not in hematocrit, prothrombin time, partial thromboplastin time, and platelet count. Clots were visible on 11 of 12 catheters in group B, which was statistically significant (p < 0.01), compared with only 3 of 12 catheters in group A. The average clot weight was 0.014+/-0.014 g in group A (range, 0.00 to 0.170 g), which was statistically significant (p < 0.01), compared with 0.216 < 0.058 g in group B (range, 0.000 to 0.620 g). Electron micrographs taken after catheters were passed through an introducer and/or protective sleeve showed that both significantly altered the surface of the catheter. The surface of the catheter was smooth and homogenous in appearance before insertion. Conversely, both the introducer and protective sleeve produced marked furrowing and a nodular appearance on the catheter surface, as shown by electron micrographs. CONCLUSION: The data from this study show that the incidence of clot formation and amount of clot formed on the surface of non-heparin-coated pulmonary artery catheters are significantly greater after passage through an introducer and/or protective sleeve. The electron micrographs also show that both introducers and protective sleeves abraded the catheters and were associated with thrombus formation on the catheter. Designing less traumatic valves on these devices is warranted and recommended.     

Advanced practice organ procurement techniques: placement of pulmonary artery catheters

Insertion of pulmonary artery catheters by organ procurement coordinators may be incorporated into donor management to optimize organ perfusion. As invasive procedures are added to coordinator roles, the organ procurement organization must include didactic instruction and supervised clinical experience as part of any training program. Policies and procedures guiding the use of the pulmonary artery catheter and the measurements obtained must be provided by the organization to guide practitioners. This article focuses on methods for insertion and basic troubleshooting of a pulmonary artery catheter.     

Indications for the use of pacing pulmonary artery catheters in cardiac surgery.

Several varieties of pulmonary artery catheters (PACs) with pacing capabilities are now available. Although specific recommendations for prophylactic perioperative placement of pacemakers have been offered previously, the authors believe that those recommendations warrant further examination, taking into consideration the availability of new pacing modalities. Toward this end, the use of pacing PACs in cardiac surgical patients was prospectively examined. In 600 consecutive adult patients with PACs placed prior to cardiopulmonary bypass (CPB), the cardiac anesthesiologist recorded if a pacing PAC was placed, the indications for placing it, and whether the catheter was used to pace. If a pacing PAC was not chosen, the anesthesiologist indicated whether cardiac pacing was needed prior to CPB. In all patients, the presence and specifics of the following five possible indications were documented: sinus node dysfunction/bradydysrhythmias, atrioventricular heart block, fascicular or bundle branch block, cardiac reoperation, and/or valvular heart disease. PACs with pacing capability were placed in 180 of the 600 patients (30.0%) and were used in 34 of these 180 patients (18.8%). In 4 of 420 patients (0.95%) without pacing PACs, cardiac pacing was needed prior to CPB. The following preoperative diagnoses were significant predictors (P less than .05) for the use or need for pacing catheters: sinus node dysfunction/bradydysrhythmias, a history of transient complete atrioventricular block, aortic stenosis, aortic insufficiency, and reoperation. The majority of adult patients undergoing cardiac surgery do not require the use of a pacing PAC prior to CPB.(ABSTRACT TRUNCATED AT 250 WORDS)     

Left coronary artery occlusion after percutaneous pulmonary valve implantation

Percutaneous pulmonary valve implantation (PPVI) is an attractive option for patients with pulmonary valve insufficiency or stenotic right ventricular outflow tracts. We present the case of a 26-year-old patient in which PPVI was used to treat d-transposition of the great arteries, uncommon coronary artery anatomy, and conduit stenosis that resulted from multiple operations on the right outflow. Days after discharge to home, she experienced acute chest discomfort correlating with ischemia noted on an electrocardiogram and elevated troponin levels. Coronary angiography confirmed mechanical compression of the left anterior descending coronary artery. The valve was removed in an emergency operation and replaced with a biological conduit.     

In vitro oxyhaemoglobin saturation measurements in haemoglobin solutions using fibreoptic pulmonary artery catheters

We compared in vitro oxyhaemoglobin saturations using two pulmonaryartery catheters (catheter So₂) with oxyhaemoglobin saturations(So₂) measured by the IL282 co-oximeter and derived partialoxyhaemoglobin saturations (partial So₂) at different oxygentensions (Po₂) in six solutions: whole blood, 50:50 mixtureof whole blood and Plasmalyte A (haemodiluted blood), 50:50mixture of whole blood and 8% pyridoxylated haemoglobin-polyoxyethylene(PHP) conjugate (WB-PHP), 75:25 mixture of 8% PHP and PlasmalyteA solution (PHP66), 50:50 mixture of 8% PHP and Plasmalyte Asolution (PHP44) and stroma-free haemoglobin solution (SFH).Calculated P₅₀ values (Po₂, vs So₂) were 3.79, 3.58, 3.49, 3.15,3.04 and 2.07 kPa, respectively. However, if partial So₂ wasused the curves were shifted to the left, reducing P₅₀. CatheterSo₂ correlated well with So in whole blood (r² > 0.99 forboth catheters), haemodiluted blood (r² > 0.98 for both catheters)and WB-PHP solution (r² = 0.94 for both catheters). In PH P44(r² = 0.64 and r² = 0.57), PHP P66 (r² = 0.40 for the Oximetrixand r² = 0.25 for the Edwards catheter) and SFH solutions (r²= 0.33 for the Oximetrix and r² = 0.22 for the Edwards catheter)both catheters performed poorly. We conclude that mixed venousoxyhaemoglobin saturations measured by oximetric pulmonary arterycatheters are inaccurate in the presence of haemoglobin solutions.For accuracy a multi-wavelength co-oximeter should be used ifblood containing PHP or SFH is to be analysed. Present address: Department of Anaesthetics, Bristol Royal Infirmary,Bristol, UK     

Temporary transmyocardial pacing using epicardial pacing wires and pacing pulmonary artery catheters

This study investigated the feasibility of transmyocardially pacing the heart using one temporary epicardial pacing lead and one endocardial lead of a pacing pulmonary artery catheter. Twenty patients undergoing cardiopulmonary bypass with cardioplegic arrest were studied 10 to 45 minutes and 18 to 30 hours after discontinuation of cardiopulmonary bypass. The Swan-Ganz Flow-Directed Pacing TD Catheter (Baxter Healthcare Corporation) was inserted in one group of 10 patients, and the Swan-Ganz Thermodilution A-V Paceport Catheter (Baxter Healthcare Corporation, Irvine, CA) was used in another group of 10 patients. Using the Pacing TD Catheter, transmyocardial atrial (TMA) pacing was successful in 14 of 16 attempts (87.5%), and transmyocardial ventricular (TMV) pacing was successful in 15 of 16 attempts (93.8%). With the AV Paceport Catheter, TMA pacing was successful in 16 of 18 attempts (88.9%), and TMV pacing was successful in 17 of 19 attempts (89.5%). Transmyocardial atrial-ventricular sequential pacing was achieved in all cases when both TMA and TMV pacing were independently successful. There were no significant differences between catheters in the success rates of either TMA or TMV. It is concluded that transmyocardial pacing is feasible using one temporary epicardial pacing lead and one endocardial lead of a pacing pulmonary artery catheter.     

The effect of heparin-coated pulmonary artery catheters on activated coagulation time in cardiac surgical patients

OBJECTIVE: To investigate the effect of heparin-coated pulmonary artery catheters (HPACs) on activated coagulation time (ACT) drawn through a non-heparin-coated introducer sheath. DESIGN: A prospective, observational study. SETTING: University teaching hospital. PARTICIPANTS: Patients scheduled for surgical procedures requiring cardiopulmonary bypass. INTERVENTIONS: With institutional review board approval, 63 patients without prior coagulopathy undergoing procedures requiring cardiopulmonary bypass were studied. Jugular venous and radial arterial ACTs were measured before and immediately after insertion of an HPAC. Additional measurements were obtained 1 hour later and 4 minutes after completion of protamine infusion. MEASUREMENTS AND MAIN RESULTS: The ACT drawn from the introducer after placement of an HPAC was 48 seconds greater than the ACT drawn before the HPAC was placed (p < 0.0001). This difference was still present 1 hour later but not after the administration of protamine or in blood drawn at any time from another site. Baseline ACTs drawn from radial arterial catheters, kept patent using a heparin flush system, resulted in elevated measurements, despite withdrawing seven times the deadspace before taking a sample. CONCLUSIONS: Blood obtained from an introducer with an HPAC in situ provides a spuriously high ACT. ACTs drawn from catheters kept patent using heparin flush also result in prolonged measurements. Baseline ACT measurement from an introducer should be obtained before placement of the HPAC.