Comparison of Intraabdominal Pressure

Study Overview
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Brief Summary
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Increased intra-abdominal pressure(IAP) might influence on perioperative morbidity related to increased CVP, PVWP, SVR, PAP and decreased venous return and cardiac output. Prone position has been known to increase IAP. In clinical field, various apparatuses has developed to minimize IAP elevation during prone position operation. In this study, we would compare the changes of IAP and respiratory system compliance according to positional apparatus in prone position.

Detailed Description
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In clinical field, Wison frame, chest rolls and Jackson table have been widely used for prone position surgery. Among those apparatus, Jackson table has padded supports under the chest and pelvis, so that the abdomen can hang freely and prevent the abdominal compression. By reducing abdominal and thoracic pressure, Jackson table would reduce blood loss, and less effects on pulmonary mechanics. But few studies has known to compare IAP with other positioning apparatus such as Wilson frame or chest roll.

Official Title
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Comparison of Intraabdominal Pressure and Respiratory Parameter Changes According to Positional Apparatus in the Prone Position

Conditions
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Prone Position

Intervention / Treatment
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* Device: Jackson surgical table
* Device: Wilson frame
* Device: Chest roll


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who are scheduled for prone positioned spinal surgery ASA Physical Status Classification System class I or II Exclusion Criteria: Patients who did not agree BMI > 30kg/m2 Patients who did not insert urinary foley catheter Patients who have COPD or emphysema Patients who have severe spine deformities such as scoliosis

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Group C<br>Group C means active comparator group which use chest rolls intraoperatively for prone position. | Device: Chest roll<br>* After standard total intravenous anesthesia using propofol and remifentanil continous infusion, patients were turned to the prone position on a chest roll. The supports were positioned vertically from shoulder to iliac crest.<br>|
| Active Comparator: Group W<br>Group W means experimental group which use Wilson frame intraoperatively for prone position. | Device: Wilson frame<br>* After standard total intravenous anesthesia using propofol and remifentanil continous infusion, patients were turned to the prone position on a Wilson frame. The supports were positioned vertically from shoulder to iliac crest.<br>|
| Experimental: Group J<br>Group J means experimental group which use Jackson surgical table intraoperatively for prone position. | Device: Jackson surgical table<br>* After standard total intravenous anesthesia using propofol and remifentanil continous infusion, patients were turned to the prone position on a Jackson table with two padded supports on each side. The supports were positioned under the lateral chest and at the iliac crest.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| changes of Intraabdominal presure (IAP) | Compare IAP changes from supine to prone according to the positional apparatus : Wilson frame, Chestrolls and Jackson table | 5 minute after position change | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes of IAP and total respiratory system comliance (Crs) accoridng to PEEP change | Compare IAP and Crs according to PEEP changes in each group. PEEP applied 0,3,6 and 9 cm H2O and recoding was done at 1min after PEEP change. Total respiratory system compliance (Crs) = TV/(Pplat-PEEP) | 1min after PEEP change | 
| changes of dead space ventilation after position change | After genearal anesthetic induction, arterial blood gas analyssis (ABGA)was done at supine position. And then the position was changed to prone. 5minutes after prone position change, ABGA repeated, and calculated the dead space ventilation at each point. Dead space ventilation (Vd/Vt) = [PaCo2-PETCO2]/PaCo2 Finally, we would compare changes of dead space ventilation after position change. | 5 minute after prone position | 
| Hemodynamic change | Check the hemodynamic changes according to PEEP change : 0,3,6 and 9 cmH2O | 1min after PEEP change | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Prone position, Intra-abdominal pressure, Respiratory system compliance, Jackson table, Wilson frame, Chest roll