Does High Intraoperative Inspired Oxygen Reduce Postoperative Arterial Oxygen Saturation?

Phase 2

Completed

Interventions: Other: FiO2 >0.9 with 3-5 cm water PEEP
Other: FiO2 (fraction of inspired oxygen) 0.3 plus PEEP (positive end expiratory pressure) 3 -5 cm water
Other: FiO2 0.3 without PEEP
Other: FiO2 >0.9 without PEEP

Brief Summary: The purpose of this study is to determine whether breathing high levels of oxygen during surgery affects oxygen levels after surgery. The second purpose of this study is to determine whether giving positive end expiratory pressure PEEP and high oxygen together affects patients oxygen levels after surgery.

Detailed Description: This is a randomized, controlled, blinded trial in patients undergoing non-abdominal surgery of the effect of intraoperative increased inspired oxygen used (FiO2\>0.9 vs. FiO2 = 0.3) on non-invasive oxygen saturation (pulse oximetry, SpO2) and amount of required supplemental oxygen in the post-anesthesia care unit (PACU); arterial oxygen partial pressure (PaO2) after 45 minutes in the PACU; room air SpO2 24 hours after surgery, and amount of supplemental oxygen required 24 hours after surgery. The purpose of the study is to determine whether absorption atelectasis induced by use of inspired oxygen concentrations in excess of 90% leads to a higher risk of hypoxemia, as evidenced by room air oxygen values and the need for supplemental oxygen. The objective of this study is to determine whether high inspired oxygen (\>0.8), which has been demonstrated to reduce the risk of surgical site infection in patients undergoing colon surgery and other major surgical procedures has side effects that limit its use to prevent infection in lower risk operations.

There are four groups of intraoperative ventilation management in this study. Fi02 0.3 plus PEEP, Fi02 0.3 without PEEP, Fi02 greater than 0.9 plus PEEP 3 to 5 cm of water, Fi02 greater than 0.9 without PEEP.

Recruitment & Eligibility

Inclusion Criteria

Patients aged 18-70 years undergoing surgery under general endotracheal anesthesia at the University of Utah Hospital Operating Room and the Huntsman Cancer Hospital Operating room who will be admitted to the hospital for at least 24 hours after surgery

Exclusion Criteria

Major (open) abdominal surgery
Major spine surgery
Craniotomy surgery
Surgeries where electrocautery or laser devices may be used near the airway (eg tracheostomy, oral surgery) because of the risk of fire with high inspired oxygen in these cases
Procedures planned for monitored anesthesia care (MAC) or regional without general anesthesia
Planned airway management with a laryngeal mask airway rather than an endotracheal tube
Procedures planned in the prone position because this increases atelectasis
Planned postoperative intubation
Planned postoperative care in the intensive care unit
Recent (within 3 weeks) chemotherapy because of the increased risk of pulmonary oxygen toxicity
History of bleomycin administration because of the increased risk of pulmonary oxygen toxicity
Diagnosed Obstructive Sleep Apnea with home continuous pulmonary airway pressure (CPAP) use
Home oxygen use
Preoperative room air (RA) SpO2 <90%
History of spontaneous pneumothorax
Emergency surgery
Pregnancy. Women of child-bearing age are routinely screened for pregnancy urine human chorionic gonadotropin, (HCG) on the morning of surgery. Patients with a positive result will be excluded from the study (and most likely will have their elective surgery cancelled).
Patient refusal

Arm && Interventions

Group	Intervention	Description
3	FiO2 >0.9 with 3-5 cm water PEEP	Group 3 will receive \> 90% oxygen plus PEEP + 3 to 5 cm of water for the duration of anesthesia and surgery
1	FiO2 (fraction of inspired oxygen) 0.3 plus PEEP (positive end expiratory pressure) 3 -5 cm water	Group 1 will receive 30% oxygen plus PEEP + 3 to 5 cm Water duration of anesthesia and surgery
2	FiO2 0.3 without PEEP	Group 2 will receive 30% oxygen without PEEP for the duration of anesthesia and surgery
4	FiO2 >0.9 without PEEP	Group 4 will receive \> 90% oxygen and no PEEP for the duration of anesthesia and surgery

Primary Outcome Measures

Name	Time	Method
Oxygen Requirement	24 hours after tracheal extubation	amount of oxygen (LPM) required to maintain SpO2 \>90%
Oxygen Requirement to Maintain SpO2>90%	45 min after emergence (tracheal extubation)	Arterial oxygen saturation by pulse oximetry (SpO2) is measured while subject is lying quietly in the post anesthesia care unit (PACU) and breathing room air (RA). Oxygen is added 0.5 liters per min (LPM) at a time to maintain SpO2 \>90%.

Secondary Outcome Measures

Name	Time	Method
Arterial Oxygen Saturation by Pulse Oximetry "(SpO2)"	45 min after tracheal extubation	SpO2 measured on room air or minimum supplemental oxygen to keep SpO2\>90%
SpO2 Postoperatively	24 hours after tracheal extubation	SpO2 is measured on room air or minimum oxygen required to keep SpO2\>90% on the ward 24 hours after tracheal extubation.