Evaluation of Impact of Nitrous Oxide on PONV in Breast Surgeries

Study Overview
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Brief Summary
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Postoperative nausea and vomiting (PONV) is considered one of the most unpleasant postoperative discomforts and lead to serious complications of aspiration of gastric contents, suture dehiscence, esophageal rupture, subcutaneous emphysema, or pneumothorax. The incidence of PONV is 30-40% in normal population and touches a peak of 75-80% in certain high-risk groups. PONV is associated with delayed recovery and prolonged hospital stay and is associated with significant morbidity. It may also result in delayed discharge, which is particularly significant after potentially ambulatory surgery. Women are 2 to 3 times more susceptible to PONV than men and breast surgery, which is primarily done in an outpatient setting, is associated with high incidence of PONV, ranging between 15% and 84% in the absence of prophylactic treatment. Nitrous oxide (N2O) has analgesic and sedative properties but may potentially increase the incidence of PONV. N2O might increase the incidence of PONV by several potential mechanisms: (1) increase in middle ear pressure (2) bowel distension, (3) activation of the dopaminergic system in the chemoreceptor trigger zone and (4) interaction with opioid receptors. N2O has been demonstrated to increase the incidence of PONV in some studies but not in others. The present study is undertaken to evaluate the effect of nitrous oxide- free general anesthesia on the undesirable clinical outcome of PONV.

Official Title
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Evaluation of Impact of Nitrous Oxide on PONV in Breast Surgeries

Conditions
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Breast Cancer

Intervention / Treatment
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* Drug: nitrous oxide anesthesia
* Drug: air anesthesia
* Device: laryngeal mask airway (LMA Supreme Size 3/4
* Drug: sevoflurane


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 1. ASA I and II female patients aged 18 years or over posted for Breast Surgeries under General Anesthesia in the main operating rooms Exclusion Criteria: ASA III, IV, V female patients Age less than 18 years Patients undergoing Breast Reconstructive Surgery Patients with contraindications to Fentanyl, Diclofenac, Paracetamol, Atracurium Chronic pain patients on long-term opioid medication Use of regional anesthetic technique (e.g. Paravertebral Block)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Air anesthesia<br>air will be used as carrier agent for maintenance of anesthesia | Drug: air anesthesia<br>* General anesthesia will be maintained by 40% oxygen (FiO2 0.4) with air and volatile anesthetic sevoflurane through laryngeal mask airway (LMA Supreme Size 3/4) or endotracheal tube (Size 7.0-7.5). All patients will receive standard anesthetic care and monitoring<br>Device: laryngeal mask airway (LMA Supreme Size 3/4<br> <br> Drug: sevoflurane<br> <br> |
| Active Comparator: Nitrous Oxide anesthesia<br>nitrous oxide will be used as carrier agent for maintenance of anesthesia | Drug: nitrous oxide anesthesia<br>* General anesthesia will be maintained by 40% oxygen (FiO2 0.4) with Nitrous Oxide and volatile anesthetic sevoflurane through laryngeal mask airway (LMA Supreme Size 3/4) or endotracheal tube (Size 7.0-7.5). All patients will receive standard anesthetic care and monitoring<br>Device: laryngeal mask airway (LMA Supreme Size 3/4<br> <br> Drug: sevoflurane<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| incidence and severity of post operative nausea and vomiting | Patients will be followed for 24 hours post-surgery or discharge from hospital whichever is earlier. postoperative nausea and vomiting intensity scale will be used to assess incidence and severity of nausea and vomiting. | up to 24 hours after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| measurement of pain score and analgesic requirements | Patients will be followed for 24 hours post-surgery or discharge from hospital whichever is earlier. Pain score will be measured by Visual Analogue Scale from 0-10. | up to 24 hours after surgery | 
| Airway device cuff pressures | airway device cuff pressure will be measured during the surgery either endotracheal tube or laryngeal mask airway which ever is applicable | During the surgery |