Comparing the Effectiveness of Lung Expansion Therapy in Adult Human Subjects

Investigators will use a convenience sampling scheme to identify potential study participants. Documentation of informed consent will be recorded. Electrical Impedance Tomography (EIT), which provides non-invasive and radiation free monitoring, will be used to monitor and measure regional distribution of ventilation during Incentive Spirometry (I.S.) and EzPAP® lung expansion therapy. The PulmoVista 500 EIT device has a reported high patient safety profile and poses minimal patient risk.

The potential benefit for study participants will not be realized directly since the investigators' aim is to only monitor regional distribution of ventilation in response to I.S. or EzPAP® lung expansion therapy. While I.S. is considered to be a standard of post-operative care, there is low quality evidence documenting I.S. effectiveness in preventing pulmonary complications after upper abdominal surgery.

Loss of dorsal lung volume (i.e., atelectasis) is an example of a post-operative pulmonary complication. EzPAP® is a lung expansion therapy that is used as an alternative to I.S. lung expansion therapy for increasing dorsal regional lung volume (i.e., Functional Residual Volume [FRC]) in an effort to prevent or reverse atelectasis. When expiratory positive airway pressures of 5, 10, and 15 cmH2O was administered to a small group of healthy human subjects, medical researchers identified that a positive pressure of 15 cmH2O was associated with the greatest FRC increase when compared to zero pressure and baseline FRC measurements.

While study participants may not benefit directly from this study, investigators anticipate that important information will be gained from EIT monitoring of regional distribution of ventilation. Future upper abdominal post-operative surgical patients may benefit from this study's findings as investigators hope to advance clinical understanding associated with these therapies with use of EIT.

Procedure set-up and device calibration will occur according to Draeger provided PulmoVista 500 EIT training and operation manual instructions:

• Study participant preparation

• Investigators will assess the participant's thorax to ensure that the skin's surface is free of body fluids that may prevent or impede electrode contact. Skin surface will be wiped clean with a dry cloth if necessary.
• Investigators will select an electrode belt and respective patient cable sizes after measuring participant's chest circumference with paper measurement tape placed across the midclavicular line at intercostal space 4 -5. Electrode belt size will be selected according to chest circumference measurement.
• A patient cable of the same electrode belt size will be selected and connected to the electrode belt before connection to participant. Investigators will align and snap connect the patient cable snaps over the electrode belt studs by aligning respective snaps and studs in ascending numerical order from 1 to 16 .
• A light spray of water may be applied to the black electrode surface on the electrode belt before it is applied to participant if natural moisture from the skin does not result in sufficient conductivity between the skin and electrodes.
• Investigators will attach an electrode belt and reference electrode to participant while they are lying supine in bed. Participant's head of bed will be positioned at 45-degrees.

• The electrode belt/cable combination will be attached around the thorax of each participant at the level of the 4th - 5th intercostal space, unless mammary tissue prevents this site of application. An alternative application site will be located immediately below the mammary tissue if necessary. Left to right belt orientation will be maintained with color coded patient cable ports signifying left and right side.
• Investigators will snap the electrode belt closed after verifying proper belt position. The belt's black electrodes should have close contact with the study participant's skin at this point.
• An adhesive ECG electrode will be place on the study participant's right upper abdominal quadrant and then the patient cable reference electrode snap will be attached to the ECG electrode.
• The patient cable will then be connected to the EIT monitoring device via a color coded trunk cable orientation that aligns with the patient cable left and right orientation
• EIT device calibration and signal check

• Investigators will initiate a PulmonVista 500 EIT monitoring device calibration each day prior to performing new study participant end-expiratory lung impedance measurements.
• A skin-electrode signal check will be performed to ensure that a minimum of 15 of 16 electrodes have sufficient contact with the participant's skin surface and signal quality is stable. Investigators will use the following status display and explanation to determine adequacy of electrode contact and signal quality.
• Monitoring sessions and Lung Expansion Therapy procedure

• Monitoring will be initiated after investigators perform PulmoVista 500 EIT device setup and calibration prior to one of the three scheduled lung expansion therapy sessions on day 1, 3, and 5 (if not discharged from hospital) after surgery.
• Approximate monitoring/measurement duration is 15-minutes.
• Lung expansion therapies will occur as follows:

• Participants will be positioned supine in bed or bedside chair with head of bed or bedside chair positioned at 45-degrees.

Incentive Spirometry Procedure Group:

• A respiratory therapist will provide instruction on Incentive Spirometry procedure performance before supervised therapy and monitoring begins.
• Participants will be asked to take 10 deep breaths through the incentive spirometer's mouthpiece, followed by a 60 second pause.
• The 10-breath cycle will be repeated three times with respiratory therapist coaching.
• Each Incentive Spirometry therapy session will last about 15 minutes three times per day.
• EIT monitoring and deep breathing measurements will occur during one of the three scheduled Incentive Spirometry sessions on day 1, 3, and 5 (if not discharged from hospital) after surgery.

EzPAP® Positive Airway Pressure Group:

• A respiratory therapist will provide instruction on EzPAP® procedure performance before supervised therapy and monitoring begins.
• Participants will be asked to breathe normally through the EzPAP® device's mouthpiece for 10 breaths, followed by a 60 second pause.
• The 10-breath cycle will be repeated three times with respiratory therapist coaching.
• Each TID EzPAP® therapy sessions will last about 15 minutes three times per day.
• EIT monitoring and deep breathing measurements will occur during one of the three scheduled Incentive Spirometry sessions on day 1, 3, and 5 (if not discharged from hospital) after surgery.

• PulmoVista set-up and monitoring sessions will be coordinated in collaboration with each participant's bedside nurse and a respiratory therapist. Initial setup and monitoring commitment time is approximately 15 - 20 minutes.
• Electrical Impedance Tomography lung monitoring and measurements will occur during one of three scheduled EzPAP® therapies on day 1, 3, and 5 (if not discharged from hospital) after surgery. Participants will continue to receive respective lung expansion therapy as ordered three times per day, but without EIT monitoring.

• Regional distribution of ventilation information will be displayed on the PulmoVista 500 device's main monitoring screen during lung expansion therapy. Clinical staff administering therapy and participants will be blinded from information displayed on the screen's monitor in an effort to reduce performance bias.
• Once lung expansion therapy session has ended, investigators will detach trunk cables from electrode cables, detach reference electrode snap from adhesive ECG electrode, unclamp the electrode belt, and then remove belt from the participant.
• Investigators will inspect the electrode belt contact area to assess for evidence of skin irritation or bruising. Participant's physician will be notified of any significant findings.

• Displaying changes
• Once the PulmoVista 500 EIT device is removed from participant's room, the investigator will change from main screen view to Display change view. Regional distribution of ventilation information displayed on the PulmoVista 500 EIT device's screen will be used to record pre and post lung expansion therapy end-expiratory lung impedance changes.
• PulmoVista 500 EIT device will be removed participant's room and returned to a storage location outside of patient care areas.

• Following each EIT to participant interface disconnect, an alcohol, aldehyde, or quaternary ammonium based compound will be soaked on a wipe cloth to disinfect the surfaces of the patient cable, electrode belt, trunk cable, and EIT unit.
• Participant's head of bed will be returned to original position or to an elevation that is preferred by the participant after therapy and monitoring session is complete.
• Participant will continue with assigned lung expansion therapy as scheduled.

Inclusion criteria

• Human subjects 18 - 79 years of age
• Post-operative upper abdominal surgery

Examples:

• Laparotomy
• Biliodigestive anastomosis
• Cholecystectomy
• Enterectomy
• Esophagectomy
• Gastrectomy
• Hepatectomy
• Pancreatectomy
• Unassisted spontaneous breathing

• Attending surgeon's approval
• Anticipated post-operative hospital length of stay greater than 3 days
• Documentation of written informed consent
• Ability to sign consent

Exclusion criteria

• Less than 18 or greater than 79 years of age
• Anticipated post-operative hospital length of stay less than 3 days
• Body mass index > 50
• Excessive chest hair
• Inability to obtain written informed consent
• Inability to follow verbal instructions
• Pregnancy-self reported
• uncontrolled body movements
• Insertion of an artificial airway
• Hemodynamic instability
• Loss of skin integrity at site where EIT electrodes and belt are projected to come into contact (i.e., chest burns, open wounds/lesions, etc…).
• Chest tube or dressings that prohibit placement of EIT electrodes and belt
• Active implants (i.e., cardiac pacemaker, implantable cardioverter-defibrillator [ICD]), diaphragm pacer, or when device compatibility is in doubt.)
• Invasive or non-invasive mechanical ventilation support
• Unstable spinal lesions or fractures
• Untreated pneumothorax
• Active hemoptysis
• Esophageal surgery
• Decision to withhold life-sustaining treatment