Measurement of arterial pressure after cardiopulmonary bypass with long radial artery catheters

Hemodynamic Monitoring In The Cardiac Surgical Patient: Comparison of Three Arterial Catheters

OBJECTIVE

Systemic systolic (SAP) and mean (MAP) arterial pressure monitoring is the cornerstone in hemodynamic management of the cardiac surgical patient, and the radial artery is the most common site of catheter placement. The present study compared 3 different arterial line procedures. It is hypothesized that a 20-G 12.7- cm catheter inserted into the radial artery will be equal to a 20-G 12.7- cm angiocath placed in the brachial artery, and superior to a 20-G 5.00 cm angiocath placed in the radial artery.

DESIGN

A prospective randomized control study was performed.

SETTING

Single academic university hospital.

PARTICIPANTS

Adult patients ≥18 years old undergoing nonemergent cardiac surgery using cardiopulmonary bypass (CPB).

INTERVENTIONS

After approval by the Rhode Island Hospital institutional review board, a randomized prospective control study to evaluate 3 different peripheral intraarterial catheter systems was performed: (1) Radial Short (RS): 20-G 5- cm catheter; (2) Radial Long (RL): 20-G 12- cm catheter; and (3) Brachial Long (BL): 20-G 12- cm catheter.

MEASUREMENTS AND RESULTS

Gradients between central aortic and peripheral catheters (CA-P) were compared and analyzed before CPB and 2 and 10 minutes after separation from CPB. The placement of femoral arterial lines and administration of vasoactive medications were recorded. After exclusions, 67 BL, 61 RL, and 66 RS patients were compared. Before CPB, CA-P SAP and MAP gradients were not significant among the 3 groups. Two minutes after CPB, the CA-P SAP gradient was significant for the RS group (p = 0.005) and insignificant for BL (p = 0.47) and RL (p = 0.39). Two-group analysis revealed that CA-P SAP gradients are similar between BL and RL (p = 0.84), both of which were superior to RS (p = 0.02 and p = 0.04, respectively). At 10 minutes after CPB, the CA-P SAP gradient for RS remained significant (p = 0.004) and similar to the gradient at 2 minutes. The CA-P SAP gradients increased from 2 to 10 minutes for BL (p = 0.13) and RL (p = 0.06). Two minutes after CPB, the CA-P MAP gradients were significant for the BL (p = 0.003), RL (p < 0.0001), and RS (p < 0.0001) groups. Two-group analysis revealed that the CA-P MAP gradients were lower for the BL group compared with the RL (p = 0.054) and RS (p< 0.05) groups. Ten minutes after CPB, the CA-P MAP gradients in the RL and RS groups remained significant (p < 0.0001) and both greater than the BL group (p = 0.002). A femoral arterial line was placed more frequently in the RS group (8/66 = 12.1%) than in the RL group (3/61 = 4.9%) and the BL group (2/67 = 3.0%). Vasopressin was administered significantly more frequently in the RS group.

CONCLUSION

Regarding CA-P SAP gradients, the RL group performed equally to the BL group, both being superior to RS. Regarding CA-P MAP gradients, BL was superior to RL and RS. Clinically, femoral line placement and vasopressin administration were fewer for the BL and RL groups when compared with the RS group. This study demonstrated the benefits of a long (12.7 cm) 20- G angiocath placed in the radial artery.

Non-invasive detection of a femoral-to-radial arterial pressure gradient in intensive care patients with vasoactive agents

BACKGROUND

In patient requiring vasopressors, the radial artery pressure may underestimate the true central aortic pressure leading to unnecessary interventions. When using a femoral and a radial arterial line, this femoral-to-radial arterial pressure gradient (FR-APG) can be detected. Our main objective was to assess the accuracy of non-invasive blood pressure (NIBP) measures; specifically, measuring the gradient between the NIBP obtained at the brachial artery and the radial artery pressure and calculating the non-invasive brachial-to-radial arterial pressure gradient (NIBR-APG) to detect an FR-APG. The secondary objective was to assess the prevalence of the FR-APG in a targeted sample of critically ill patients.

METHODS

Adult patients in an intensive care unit requiring vasopressors and instrumented with a femoral and a radial artery line were selected. We recorded invasive radial and femoral arterial pressure, and brachial NIBP. Measurements were repeated each hour for 2 h. A significant FR-APG (our reference standard) was defined by either a mean arterial pressure (MAP) difference of more than 10 mmHg or a systolic arterial pressure (SAP) difference of more than 25 mmHg. The diagnostic accuracy of the NIBR-APG (our index test) to detect a significant FR-APG was estimated and the prevalence of an FR-APG was measured and correlated with the NIBR-APG.

RESULTS

Eighty-one patients aged 68 [IQR 58-75] years and an SAPS2 score of 35 (SD 7) were included from which 228 measurements were obtained. A significant FR-APG occurred in 15 patients with a prevalence of 18.5% [95%CI 10.8-28.7%]. Diabetes was significantly associated with a significant FR-APG. The use of a 11 mmHg difference in MAP between the NIBP at the brachial artery and the MAP of the radial artery led to a specificity of 92% [67; 100], a sensitivity of 100% [95%CI 83; 100] and an AUC ROC of 0.93 [95%CI 0.81-0.99] to detect a significant FR-APG. SAP and MAP FR-APG correlated with SAP (r2 = 0.36; p < 0.001) and MAP (r2 = 0.34; p < 0.001) NIBR-APG.

CONCLUSION

NIBR-APG assessment can be used to detect a significant FR-APG which occur in one in every five critically ill patients requiring vasoactive agents.

Pressure difference between radial and femoral artery pressure in minimally invasive cardiac surgery using retrograde perfusion

Objective:

To investigate whether radial artery pressure is a reliable surrogate measure of central arterial pressure as approximated by femoral artery pressure in minimally invasive cardiac surgery with retrograde perfusion via femoral cannulation.

Method:

Fifty-two consecutive patients undergoing minimally invasive cardiac surgery were prospectively included in this study. Cardiopulmonary bypass was established via a femoral artery cannulation and femoral vein. Radial and femoral arterial pressures were recorded continuously, and the pressure differential between them was calculated for both systolic and mean arterial pressures. The agreement between measurements from the two arteries was compared using Bland–Altman plots. An interval of 95% limits of agreement of less than 20 mm Hg was set as satisfactory agreement.

Results:

Average age was 65 ± 14 years. With respect to systolic arterial pressure, 28 patients (54%) had a peak pressure differential between radial and femoral arteries ⩾20 mm Hg. With respect to mean arterial pressure, only five patients (9%) had a peak pressure differential ⩾20 mm Hg. The pressure differential changed with time. Pressure differential in systolic arterial pressure was 5 ± 8 mm Hg until aortic declamping, then increased to a peak of 23 ± 16 mm Hg when cardiopulmonary bypass was turned off. The femoral systolic arterial pressures were significantly greater than radial systolic arterial pressures from time of aortic declamping to 20 min after cardiopulmonary bypass. The Bland–Altman plots revealed large biases and poor agreement in this period.

Conclusion:

Radial and femoral systolic artery pressure readings can differ significantly in minimally invasive cardiac surgery with retrograde perfusion. Intraoperative arterial pressure management based solely on radial systolic arterial pressure readings should be avoided.

Needle-guided ultrasound technique for axillary artery catheter placement in critically ill patients: A case series and technique description

PURPOSE

Axillary arterial cannulation for blood pressure monitoring has been reported in adults since 1973. Reported failure rates using palpation landmarks are high. This report describes a needle-guided ultrasound technique for axillary arterial line placement in critically ill patients.

METHODS

A retrospective review of all patients requiring axillary arterial cannulation attempts with ultrasound-assisted needle guidance for hemodynamic monitoring was performed from July 2010 to June 2016 at a single institution.

RESULTS

One hundred fifty nine (159) cannulation attempts were performed in 155 patients. The overall success rate was 97%, with a first pass success rate of 84%. Inexperienced operators performed 49% of procedures under direct faculty supervision, and had a 99% success rate, which was not different from experienced operators. Almost 20% of patients had moderate-to-severe coagulopathy (platelets<50k/uL, INR>2.0 or PTT>60s). Complications reported included the following: nonfunctioning of catheter (6%) and hematoma (6%). Ischemia was noted in 2 patients (1%), but only one was attributed to the arterial catheter.

CONCLUSIONS

Use of the needle-guided ultrasound assisted approach for axillary arterial line placement is easily teachable and can be used to promote safe and successful placement of axillary arterial lines for novice learners.

Late evaluation of upper limb arterial flow in patients after long radial (PiCCO™) catheter placement

BACKGROUND

The purpose of the study was to assess blood flow in the upper limb arteries after prolonged catheterization with long radial artery catheters (LRC) which reach the subclavian artery compared to catheterization with standard short radial artery catheters (SRC) and a group of upper limb flow without any catheter placement (NOCATH), with both SRC and NOCATH as control groups.

METHODS

Prospective observational study with 20 patients admitted to ICU (40 upper limbs) with LRC and/or SRC inserted >48 h for hemodynamic monitoring. More than 45 days after catheter withdrawal, patients underwent a Doppler ultrasound study of both upper limbs. Arterial flows of arms with LRC (FlowLRC) were compared with arterial flows of arms with SRC (FlowSRC) and those without any catheter (FlowNOCATH).

RESULTS

Flow in the ulnar, brachial, and subclavian arteries did not show any significant difference between the two types of catheters. The only significant difference was in the radial arteries, showing a lower mean flow in the arms with LRC than in the arms with SRC (2.2 vs. 8.5 cc/min; p = 0.041). Flow reduction in the radial artery (74%) in the arms with LRC compared to the SRC arms showed a tendency to increase ulnar flow as a compensatory mechanism. None of the patients with LRC included in our study had any ischemic events, in spite of observing complete flow occlusion in three radial arteries (18%) from the Doppler study.

CONCLUSIONS

In this sample, the use of PiCCO long radial catheters reaching the subclavian artery did not produce chronic significant changes in brachial or subclavian flows. However, LRC produces a significant reduction in radial flow and a tendency to increase ulnar flow. When comparing these blood flow changes with those produced by SRC use, only the radial flow reduction was significantly lower, whereas the other arterial flow changes did not significantly differ.

Radial mean arterial pressure reliably reflects femoral mean arterial pressure in uncomplicated pediatric cardiac surgery

OBJECTIVE

To see if radial mean arterial pressure reliably reflects femoral mean arterial pressure in uncomplicated pediatric cardiac surgery.

DESIGN

An ethics committee-approved prospective interventional study.

SETTING

Operating room of a tertiary care hospital.

PARTICIPANTS

Forty-five children aged 3 months to 4 years who underwent pediatric cardiac surgery with hypothermic cardiopulmonary bypass.

MEASUREMENTS AND MAIN RESULTS

Simultaneous femoral and radial arterial pressures were recorded at 10-minute intervals intraoperatively. A pressure gradient>5mmHg was considered to be clinically significant. The patients' mean age was 14±11 months and and mean weight was 8.0±3.0kg. A total of 1,816 simultaneous measurements of arterial pressure from the radial and femoral arteries were recorded during the pre-cardiopulmonary bypass, cardiopulmonary bypass, and post-cardiopulmonary bypass periods, including 520 (29%) systolic arterial pressures, 520 (29%) diastolic arterial pressures, and 776 (43%) mean arterial pressures. The paired mean arterial pressure measurements across the 3 periods were significantly and strongly correlated, and this was true for systolic arterial pressures and diastolic arterial pressures as well (r>0.93 and p<0.001 for all). Bland-Altman plots demonstrated good agreement between femoral and radial mean arterial pressures during the pre-cardiopulmonary bypass, cardiopulmonary bypass, and post-cardiopulmonary bypass periods. A significant radial-to-femoral pressure gradient was observed in 150 (8%) of the total 1,816 measurements. These gradients occurred most frequently between pairs of systolic arterial pressure measurements (n = 113, 22% of all systolic arterial pressures), followed by mean arterial pressure measurements (n = 28, 4% of all mean arterial pressures) and diastolic arterial pressures measurements (n = 9, 2% of all diastolic arterial pressures). These significant gradients were not sustained (ie, were not recorded at 2 or more successive time points).

CONCLUSIONS

The results suggested that radial mean arterial pressure provided an accurate estimate of central mean arterial pressure in uncomplicated pediatric cardiac surgery. There was a significant gradient between radial and femoral mean arterial pressure measurements in only 4% of the mean arterial pressure measurements, and these significant gradients were not sustained.

Deep hypothermic circulatory arrest and the femoral-to-radial arterial pressure gradient

OBJECTIVES

To determine the femoral-to-radial arterial pressure gradient, as well as the factors associated with them, in patients receiving cardiopulmonary bypass (CPB) with profound hypothermia and circulatory arrest.

DESIGN

Retrospective automated hemodynamic record review.

SETTING

University hospital.

PARTICIPANTS

Patients undergoing pulmonary thromboendarterectomy with deep hypothermic circulatory arrest.

MEASUREMENTS AND MAIN RESULTS

The automated hemodynamic records of 54 consecutive patients undergoing pulmonary thromboendarterectomy with deep hypothermic circulatory arrest were reviewed, comparing the femoral and radial arterial pressures throughout the intraoperative period. In 20 of the patients, the hemodynamic data from the first 16 postoperative hours were also studied. Forty-one of 54 (76%) of the patients exhibited a mean arterial gradient of at least 10 mmHg either during or after CPB, femoral being higher. Clinically significant gradients were noted throughout the CPB period and the post-CPB period in these patients. In the 54 patients studied, the systolic blood pressure (SBP) gradient was 32 +/- 19 mmHg after CPB (95% confidence limits 28.2 mmHg, 39.0 mmHg), and the mean arterial pressure (MAP) gradient was 6.3 +/- 4.9 mmHg (95% confidence limits 5.5 mmHg, 8.6 mmHg). The duration of clinically significant SBP (>10 mmHg) and MAP (>5 mmHg) gradients in the postoperative period were 5.2 +/- 5.7 hours and 5.8 +/- 7.2 hours, respectively. Advanced age correlated with high post-CPB pressure gradients in this population and was associated with prolonged postoperative resolution of the gradients.

CONCLUSIONS

The femoral-to-radial arterial pressure gradients, particularly systolic, after CPB, were greater and of longer duration in these patients undergoing deep hypothermic circulatory arrest than gradients previously reported for routine CPB. Central arterial pressure monitoring is recommended for patients undergoing deep hypothermic circulatory arrest, being valuable both for intraoperative and postoperative care.

Measurement of cardiac output by transpulmonary arterial thermodilution using a long radial artery catheter. A comparison with intermittent pulmonary artery thermodilution

Cardiac output can be measured accurately by transpulmonary arterial thermodilution using the PiCCO (Pulsion Medical Systems, Munich, Germany) system with a femoral artery catheter. We have investigated the accuracy of a new 50 cm 4 French gauge radial artery catheter and the ability to use the system with a shorter radial catheter. We studied 18 patients who had undergone coronary artery surgery and made three simultaneous measurements of cardiac output by arterial thermodilution and with a pulmonary artery catheter. The radial catheter was withdrawn in 5 cm increments and the measurements were repeated. We found close agreement between arterial thermodilution and pulmonary artery thermodilution with a mean (SD) bias of 0.38 (0.77) l x min(-1). Arterial thermodilution became unreliable once the catheter had been withdrawn by more than 5 cm. We conclude that cardiac output measurement with arterial thermodilution with a radial catheter is interchangeable with that derived from a pulmonary artery catheter, and that a centrally sited arterial catheter is required for accurate determination of cardiac output by transpulmonary arterial thermodilution.

Clinical review: complications and risk factors of peripheral arterial catheters used for haemodynamic monitoring in anaesthesia and intensive care medicine

In order to evaluate the complications and risk factors associated with peripheral arterial catheters used for haemodynamic monitoring, we reviewed the literature published from 1978 to 2001. We closely examined the three most commonly used arterial cannulation sites. The reviewed papers included a total of 19,617 radial, 3899 femoral and 1989 axillary artery catheterizations. Factors that contribute to higher complication rates were investigated. Major complications occurred in fewer than 1% of the cases, and rates were similar for the radial, femoral and axillary arteries. We conclude that arterial cannulation is a safe procedure.

Comparison of axillary artery or brachial artery pressure with aortic pressure after cardiopulmonary bypass using a long radial artery catheter

Arterial pressure measured in a peripheral artery may significantly underestimate central arterial pressure after discontinuation of cardiopulmonary bypass (CPB). Arterial pressure measured with a 50 cm radial artery catheter advanced into the brachial or axillary artery was compared to ascending aortic pressure in 31 patients before and after discontinuation of CPB. The radial artery catheter extended proximally into the brachial artery in 8/31 patients, and into the axillary artery in 23/31 patients. The patient's age, pre-CPB cardiac ejection fraction, and surgical procedures were similar in both groups. The systolic arterial pressure measured in the ascending aorta was found to be significantly different from that in the axillary artery after CPB, whereas the mean and diastolic pressures were not. The average aorta-to-axillary artery systolic pressure gradient was -3.0 +/- 4.0 mmHg, with no patient having a gradient greater than 10 mmHg. The systolic and mean arterial pressures measured in the ascending aorta were found to be significantly different from that in the brachial artery after discontinuation of CPB, whereas the diastolic pressure was not. The average aorta-to-brachial artery systolic pressure gradient was 6.9 +/- 6.9 mmHg, with 3/8 patients having a gradient greater than 10 mmHg. Long radial artery catheters, placed using the Seldinger technique, provide an accurate estimate of central aortic pressure after CPB when they are advanced into the axillary artery. Sites more distal than the axillary artery may result in significant underestimation of the central aortic pressure in these patients.

What's new in monitoring the coronary surgery patient?

Monitoring has been extensively reviewed in most textbooks of cardiothoracic surgery and anaesthesia, particularly in the recent textbooks on monitoring edited by Carol L Lake 1 and Casey D Blitt 2 and in the Journal of Clinical Monitoring. Although monitoring properly includes both pre- and postoperative periods, this review will concentrate exclusively on the operative period. I will also concentrate on new approaches or information which relate to more traditional approaches to monitoring. The emphasis in this review will not be on what we can monitor, but rather on what we should monitor. In this regard, I will analyse accuracy and identify sources of error and try to answer the following questions. Does the device or parameter measure (monitor) what we want to know? Does it improve patient outcome and safety? Is it cost-effective? Unfortunately, data are not always available to answer all these questions at present, but hopefully the discussions will make us aware of what we do and do not know, and what we should look for in the near future.