IRB-HSR# 15084 A Prospective, Unblinded, Controlled Study to Evaluate the Effect of the ITPR in Patients Undergoing OPCAB Surgery

• hemodynamic changes [ Time Frame: during surgery ] [ Designated as safety issue: No ]
  hemodynamic changes noted, including systemic blood pressure, pulmonary arterial pressure, pulse pressure, heart rate (recorded most reliably from the arterial line), cardiac output (CO), cardiac index (CI), mixed venous oxygen saturation (SVO2), SVR, pulmonary vascular resistance (PVR), and stroke volume (SV).
  
  

• use of vasopressors [ Time Frame: during surgery ] [ Designated as safety issue: No ]
  the specific drug and dos will be comparedage used during surgery
  
  
• IV fluids administered [ Time Frame: during surgery ] [ Designated as safety issue: No ]
  the type & amount of fluid administered suring surgery will be compared
  
  
• the number of times the surgeon must reposition the heart for treatment of hypotension [ Time Frame: during surgery ] [ Designated as safety issue: No ]
  the number of times the surgeon must reposition the heart for treatment of hypotension will be compared, and ascertain whether the ITPR will help patients tolerate the cardiac displacement better, thus decreasing the time required to complete the bypass graft anastamosis.
  
  
• cardiac ischemia [ Time Frame: during surgery ] [ Designated as safety issue: No ]
  ECG will be monitored intraoperatively for signs of ischemia including ST changes, greater than 1mm depression or elevation.
  
  
• diuretics administered [ Time Frame: 48 hours after surgery ] [ Designated as safety issue: No ]
  Postoperatively, we will record the need for and amount of diuretic required.for the first 48 hours post-operatively.
  
  

A new method to improve cardiac performance during OPCAB surgery is needed in order to avoid the administration of large amounts of intravenous volume, reduce vasopressor medications, and thus improve cardiac function and reduce the need for postoperative diuresis.

The CirQlator TM Intrathoracic Pressure Regulator (ITPR) is an FDA-approved device intended to increase circulation and blood pressure in hypovolemic and cardiogenic shock. The device is inserted within a standard respiratory circuit between the patient and the ventilator. It functions by decreasing intrathoracic pressure during the expiratory phase to subatmospheric levels after each positive pressure ventilation. The decrease in intrathoracic pressure creates a vacuum within the thorax relative to the rest of the body thereby enhancing blood return to the heart and consequently increasing cardiac output and blood pressure. Activation of the device is also accompanied by a decrease in systemic vascular resistance (SVR). The end result is a device that simultaneously improves cardiac output by increasing preload and decreasing systemic vascular resistance (SVR) while increasing coronary perfusion pressure by increasing blood pressure and decreasing left ventricular end systolic pressure and volume (LVESP/LVESV).7-14