Cannulation for Cardiopulmonary Bypass

*Emily Bond, Crystal Valadon and Mark Slaughter*

### **Abstract**

Cardiac surgery has made significant progress since the advent of cardiopulmonary bypass. Arterial cannulation for bypass is a cornerstone to most cardiac procedures. Choosing an ideal cannulation site, employing peri- and intraoperative imaging, selecting an appropriate cannula, and avoiding complications are vital to success. These, along with the steps to arterial cannulation, are discussed in this chapter.

**Keywords:** cardiopulmonary bypass, arterial cannulation, aortic cannulation, femoral cannulation, axillary cannulation

#### **1. Introduction**

Cardiopulmonary bypass serves the purpose of acting in place of the patient's heart and lungs during a cardiac operative procedure. The mechanism allows for blood to become reoxygenated in order to ensure sufficient perfusion throughout the patient's body. The application of this novel concept is attributed to John Gibbon Jr., and its first successful clinical use was reported in 1953 [1]. However, it did not become more practically available until in 1955 when both John Kirklin at the Mayo Clinic and C. Walton Lillehei at the University of Minnesota introduced its routine use in open heart surgery [1].

The utilization of cardiopulmonary bypass increased significantly between the years 1960 and 1969 due to the increased demand brought on by advances in the field of cardiothoracic surgery. Prior to this era, the majority of cardiac surgeries being performed addressed congenital heart disease in an expeditious fashion. Bypass allowed more complex problems to be repaired by allowing more time for the surgeon to operate while the patient maintained perfusion. Additionally, the need for reliable extracorporeal circulation was expanded with the introduction of coronary artery bypass grafting, the development of artificial heart valves, the utilization of deep hypothermia to facilitate circulatory arrest, and heart transplantation [1].

With the use of cardiopulmonary bypass increasing so dramatically, research into further understanding and improvement of the process was initiated, particularly in the 1980s. Special investigative attention was given to the inflammatory reaction induced by cardiopulmonary bypass, the development of drugs to reduce adverse neurologic events, and flow pulsatility [1–3]. The field of cardiothoracic surgery and the advancement of cardiopulmonary bypass have continued to be refined and improved.

### **2. Arterial cannulation sites**

Arterial cannulation is necessary in order to provide oxygenated blood systemically during cardiopulmonary bypass. Currently, there are three different sites that can be utilized to achieve this function:


The most commonly utilized site is the distal ascending aorta. In this instance, cannulation is performed near the origin of the brachiocephalic trunk [4]. In the event this site is not a viable option, the femoral artery is the standard peripheral site. Femoral arterial cannulation can be accessed both by open cutdown technique and percutaneous techniques. If a percutaneous approach is taken, the arteriotomy will need to be closed using a percutaneous vessel closure device or an open repair. If both the distal ascending aorta and femoral artery prove to be high-risk options due to complications, the axillary artery is the next alternative, preferably on the right side. This vessel is accessed via the deltopectoral groove via a standard infraclavicular cutdown.

#### **3. How to choose the appropriate arterial cannulation site**

Determining which arterial cannulation site to use depends on factors such as the procedure being performed, patient body habitus, and the degree of atherosclerotic disease present [5]. Therefore, each case should be evaluated individually to decide upon the best course of action. Based on the surgical procedure, it must be determined if the distal ascending aorta is an appropriate cannulation site. Instances where this may not be the case include repeat sternotomy, emergency surgery, minimally invasive surgery, anatomic anomalies, prohibitive atherosclerotic disease, and robotic cardiac surgery, among others [4]. The benefits of antegrade versus retrograde flow must also be weighed. Both the distal ascending aorta and the axillary artery have the advantage of anterograde flow, whereas the femoral artery exhibits retrograde flow [5]. This is especially important in cases involving aortic dissection. When contemplating using femoral access, excessive arterial calcification, previous groin operations, and body habitus must be considered.

#### **4. Preoperative imaging**

Obtaining the appropriate imaging studies prior to conducting cardiopulmonary bypass is essential, as the information gathered can influence the surgical approach. There are several different imaging options that can be utilized. The most routine preoperative imaging study performed is chest radiography. Chest x-ray (anteroposterior and lateral) can provide information such as the size and shape of the cardiac silhouette, traces of previous thoracic interventions or hardware, severe atherosclerotic disease, and significant pulmonary disorders, in addition to other pertinent information [6]. In the current era, nearly every patient who presents with chest pain has CT imaging ordered by a provider during

**15**

cannula [10].

**6. Steps to cannulation**

*Cannulation for Cardiopulmonary Bypass DOI: http://dx.doi.org/10.5772/intechopen.86033*

planning of the surgical procedure [7].

**5. Types of cannulas**

the work-up. Chest CT can provide an abundance of information regarding the patient's anatomy and quality of vasculature, as well as many anomalies and abnormalities. Certain findings such as porcelain aorta, dissections, and subclavian stenosis can alter the operative treatment plan. Recent data has suggested that CT should be the standard preoperative imaging for patients with prior sternotomy, as doing so has been associated with a lower risk of perioperative complication [7]. This type of imaging allows for the surgeon to visualize and analyze the sternum more effectively, providing information that will ultimately optimize

Additional imaging modalities that can be utilized preoperatively include transesophageal echocardiogram (TEE) and transthoracic echocardiogram (TTE). Echocardiography has the ability to provide critical information in order to optimize hemodynamics and identify conditions that had not been appreciated on static imaging [8]. In regard to determining which form of echocardiography (TEE vs. TTE) is most appropriate, several factors should be considered. The imaging quality of TTE is limited by the structures the signal must traverse. TEE has shown to provide superior imaging, particularly for posterior structures that are closer in association to the esophagus including the aorta and both atria [9]. The disadvantages of TEE in comparison to TTE include its invasive nature, requirement for sedation, and increased time to perform. Despite these factors, TEE's improved ability to visualize critical structures suggests that it should be the echocardiography imaging of choice for procedures requiring cardiopulmonary bypass. In our practice, TEE is regularly performed in the operating room after induction and prior to incision to

Aortic cannulas come in a variety of commercially available options. Cannula size should be selected in conjunction with the perfusionist team so as to utilize the appropriate cannula for adequate flow within the circuit. Too large of a cannula may require an aortotomy that is difficult to close in a standard fashion, while too small of a cannula will not allow sufficient flows. A narrower cannula can cause high pressure gradients, cavitation, or jets of flow which can increase the likelihood of dissection. Diffusion-tip cannulas are available which provide multidirectional flow to reduce jets. The tip of the cannula may be straight, tapered, or angled, as well as made from metal or plastic. Various tip modifications, such as flanges or adjustable rings, are available to prevent the cannula from being inserted too far into the aorta and impeding flow to the head vessels. When using an alternate arterial cannulation site, certain adjustments must be made. Adequate bypass support via femoral cannulation is best achieved with a long, wire-reinforced cannula, whereas the diameter of the axillary artery must be taken into account when selecting an appropriate

Arterial cannulation is almost always completed prior to venous cannulation during the setup for cardiopulmonary bypass. The steps below outline the appropri-

1.Identify the appropriate cannulation site through the use of preoperative imag-

ate manner in which arterial cannulation can be achieved.

ing, surgical history, and operator preference (**Figure 1**).

verify and support the other preoperative cardiac function tests.

#### *Cannulation for Cardiopulmonary Bypass DOI: http://dx.doi.org/10.5772/intechopen.86033*

*Cardiac Surgery Procedures*

**2. Arterial cannulation sites**

• Distal ascending aorta

• Femoral artery

• Axillary artery

clavicular cutdown.

be considered.

**4. Preoperative imaging**

can be utilized to achieve this function:

Arterial cannulation is necessary in order to provide oxygenated blood systemically during cardiopulmonary bypass. Currently, there are three different sites that

The most commonly utilized site is the distal ascending aorta. In this instance, cannulation is performed near the origin of the brachiocephalic trunk [4]. In the event this site is not a viable option, the femoral artery is the standard peripheral site. Femoral arterial cannulation can be accessed both by open cutdown technique and percutaneous techniques. If a percutaneous approach is taken, the arteriotomy will need to be closed using a percutaneous vessel closure device or an open repair. If both the distal ascending aorta and femoral artery prove to be high-risk options due to complications, the axillary artery is the next alternative, preferably on the right side. This vessel is accessed via the deltopectoral groove via a standard infra-

Determining which arterial cannulation site to use depends on factors such as the procedure being performed, patient body habitus, and the degree of atherosclerotic disease present [5]. Therefore, each case should be evaluated individually to decide upon the best course of action. Based on the surgical procedure, it must be determined if the distal ascending aorta is an appropriate cannulation site. Instances where this may not be the case include repeat sternotomy, emergency surgery, minimally invasive surgery, anatomic anomalies, prohibitive atherosclerotic disease, and robotic cardiac surgery, among others [4]. The benefits of antegrade versus retrograde flow must also be weighed. Both the distal ascending aorta and the axillary artery have the advantage of anterograde flow, whereas the femoral artery exhibits retrograde flow [5]. This is especially important in cases involving aortic dissection. When contemplating using femoral access, excessive arterial calcification, previous groin operations, and body habitus must

Obtaining the appropriate imaging studies prior to conducting cardiopulmonary bypass is essential, as the information gathered can influence the surgical approach. There are several different imaging options that can be utilized. The most routine preoperative imaging study performed is chest radiography. Chest x-ray (anteroposterior and lateral) can provide information such as the size and shape of the cardiac silhouette, traces of previous thoracic interventions or hardware, severe atherosclerotic disease, and significant pulmonary disorders, in addition to other pertinent information [6]. In the current era, nearly every patient who presents with chest pain has CT imaging ordered by a provider during

**3. How to choose the appropriate arterial cannulation site**

**14**

the work-up. Chest CT can provide an abundance of information regarding the patient's anatomy and quality of vasculature, as well as many anomalies and abnormalities. Certain findings such as porcelain aorta, dissections, and subclavian stenosis can alter the operative treatment plan. Recent data has suggested that CT should be the standard preoperative imaging for patients with prior sternotomy, as doing so has been associated with a lower risk of perioperative complication [7]. This type of imaging allows for the surgeon to visualize and analyze the sternum more effectively, providing information that will ultimately optimize planning of the surgical procedure [7].

Additional imaging modalities that can be utilized preoperatively include transesophageal echocardiogram (TEE) and transthoracic echocardiogram (TTE). Echocardiography has the ability to provide critical information in order to optimize hemodynamics and identify conditions that had not been appreciated on static imaging [8]. In regard to determining which form of echocardiography (TEE vs. TTE) is most appropriate, several factors should be considered. The imaging quality of TTE is limited by the structures the signal must traverse. TEE has shown to provide superior imaging, particularly for posterior structures that are closer in association to the esophagus including the aorta and both atria [9]. The disadvantages of TEE in comparison to TTE include its invasive nature, requirement for sedation, and increased time to perform. Despite these factors, TEE's improved ability to visualize critical structures suggests that it should be the echocardiography imaging of choice for procedures requiring cardiopulmonary bypass. In our practice, TEE is regularly performed in the operating room after induction and prior to incision to verify and support the other preoperative cardiac function tests.
