Standard monitoring

Standard monitoring should be used as described in Chapter 15.

Intra-arterial blood pressure monitoring should be used if, based on the patient’s condition or the nature of the surgical procedure, rapid hemodynamic alterations are anticipated, or frequent ABG evaluation is needed.

1. Compression of the heart and great vessels may occur during thoracic surgical exposure. Continuous blood pressure monitoring allows for the immediate diagnosis of hemodynamic instability.
2. Manipulations during surgical procedures on peripheral lung tissue, such as thoracoscopic wedge resection, are less likely to compress the heart or great vessels. Intermittent blood pressure monitoring may be sufficient in these cases.
3. Arterial line is helpful for hemodynamic monitoring of patients undergoing thoracic surgery.
4. In the lateral position, it is possible for blood flow to the dependent arm to be impaired by compression of the axilla. Pulsatile flow to the dependent arm should be monitored with an arterial catheter or a pulse oximeter.
5. During mediastinal surgery (eg, mediastinoscopy), it is possible for the innominate artery to be compressed, restricting flow to the right carotid and brachial arteries. Perfusion to the right arm should be monitored by pulse oximeter. Immediate feedback to the surgeon will allow decompression of the innominate artery. Blood pressure monitoring of the left arm should be available to allow monitoring of systemic arterial pressure in the event that the surgeon is unable to relieve compression of the innominate artery.

The use of additional invasive monitors is dictated by the patient’s comorbidities. If a pulmonary artery catheter is placed:

1. It is customarily inserted from the nondependent side of the neck. If the catheter interferes with the surgical resection, it can be retracted into the main pulmonary artery and readvanced when the artery on the operative side is clamped.
2. Pressure measurements referenced to the atmosphere may be affected by lateral positioning and opening the chest. Trends in central venous pressure, pulmonary artery pressure, and pulmonary artery occlusion pressure should be monitored for these changes. Cardiac output and stroke volume measurements should remain accurate.