Please select the eligibility criteria that correspond to the clinical trial below.
Title: The Effects of Hypercapnia, Supplemental Oxygen, and Dexamethasone on Surgical Wound Infection
Brief Summary: The investigators will test the hypotheses that mild hypercapnia and supplemental oxygen reduce wound infection risk in patients undergoing colon resection. The investigators will simultaneously test the hypothesis that low-dose dexamethasone (a common treatment for postoperative nausea and vomiting) does not increase infection risk.


Options:
A: Inclusion Criteria:

* Colon resection expected to last \>2 and \<6 hours

Exclusion Criteria:

* Bowel obstruction
* Fever
B: Inclusion Criteria:

* Patients over or equal to the age of 18 years old who can understand the study protocol and are able to give consent
* Patients with an American Society of Anaesthesiology (ASA) classification 1 to 3
* Patients must have a preoperative oral 24 hour opioid consumption of less than or equal to 30 mg morphine equivalents
* Patients must be able to understand and be able to use patient controlled analgesia
* Patients must be undergoing a primary total knee arthroplasty with neuraxial anesthesia

Exclusion Criteria:

* Patients with a contraindication to neuraxial and/or regional anaesthesia
* Patients with an allergy to local anaesthetics
* Patients who have chronic pain not related to their knee joint
* Patients with chronic opioid use (daily or almost daily use \>3 months)
* Patients with contraindications to dexamethasone (allergy, infection, Insulin dependent Diabetes Mellitus)
* Patients with pre-existing neuropathy
* Patients with hepatic failure
* Patients with renal failure with eGFR\<60
* Patients with allergy to ketorolac or NSAIDs
C: Inclusion Criteria:

* Age 18 or older with an American Society of Anesthesiologists (ASA) physical status of I to II
* Scheduled for vitrectomy under local anesthesia

Exclusion Criteria:

* Hypersensitivity to study drug or rescue medication
* Preoperative score for nausea greater than 4 out of 10 points
* Subjects who suffer from chronic nausea and/or vomiting
* Severe hepatic insufficiency (Child-Pugh score \> 9)
* Other antiemetic within 12 hours prior to surgery
* Patients unable to undergo a local anesthetic
* Subjects with clinically significant or unstable cardiac, respiratory, hepatic, renal, or other major organ system disease
* Psychotic illness or depression
* Addiction to illicit substances or alcohol
* Non-psychotic emotional disorders
* Pregnant or lactating
* Subjects who, in the opinion of the investigator, would experience an unacceptable risk from administration of study drug
D: Inclusion Criteria:

* 18-80 yrs of age
* American Society of Anesthesiologists (ASA) physical status 1-3
* Scheduled for outpatient TEP bilateral inguinal hernia repair

Exclusion Criteria:

* Patients refusal to participate
* inability to give consent
* drug allergies to medications used in study
* pregnancy
* bleeding diathesis
* conversion to an open procedure
* any subject whose anatomy, or surgical procedure, in the opinion of the investigator might preclude the potential successful performance of a TAP block
* any subject whose anatomy, or surgical procedure, in the opinion of the investigator, might preclude the potential successful performance of a TAP block

Answer: A