Traditionally, patients are kept nil-per-os (NPO) or nil-by-mouth (NBM) prior to invasive cardiac procedures. There exists neither clear evidence nor guidance about the benefits of this.

The investigators aim to assess if there is a reduced incidence of vasovagal complications (primary outcome) and the combined incidence of aspiration pneumonia, change in eGFR, participant satisfaction if participants are not kept fasting.

This (pilot) randomised control trial will have an intervention arm allowing participants to drink clear liquids freely up to 1 hour before the procedure versus keeping them traditionally NPO.

240 patients will be randomised with 120 participants in each arm.

Introduction, background and justification for the study

Patients are traditionally kept Nulla-Per-Os/Nil-By-Mouth (NPO/NBM) for 4-6 hours prior to cardiac procedures including: diagnostic coronary angiograms, right heart catheters, percutaneous coronary interventions and device therapies to minimize the risk of vomiting and pulmonary aspiration during sedation or general anesthesia. The risk of developing pulmonary aspiration is 0.0015 % following emergency coronary artery bypass (CABG) surgery in patients without pre-procedural fasting. There is currently no data available regarding the risk of aspiration during cardiac angiographic interventions, but the risk is likely lower than that of emergency CABG. Currently no North-American or European guidelines require patients to be fasted before cardiac procedures.

The incidence of emergency CABG following cardiac catheterization is between 0.15 % to 0.4 %, whilst that of cardiac arrest is about 1%. In the subset of patients who develop cardiac arrest during elective cardiac catheterization or PCI, the incidence of pulmonary aspiration is low and similar between survivors and non-survivors (8.9% of patients who developed cardiac arrest).

Unsurprisingly, patients admitted with acute MI undergoing Primary PCI (PPCI) are not fasted beforehand and the need for emergency intubation/CABG remains rare in these patients.

A study has shown a rare occurrence of pulmonary aspiration in general anesthesia with a risk of 0.02% for elective and 0.1% for emergency procedures. In two randomized controlled trials, no case of pulmonary aspiration was reported despite the absence of pre-procedure fasting and use of Midazolam/Diazepam/etomidate.

Similarly, in an observational study no patient developed pulmonary aspiration. A Cochrane review did not show an increased risk of pulmonary aspiration with shorter fluid fast. A review article did not report an increased risk of pulmonary aspiration in non-fasted patients in the emergency department. However, a prospective multicenter emergency-department study of 2623 patients revealed only one patient developed aspiration pneumonia following the use of sedation. There is current consensus in the anesthesia literature that it is safe for healthy individuals to drink clear fluids up to 2 hours before induction of general anesthesia. It is recommended that 2 hours fasting for clear fluids, 6 hours for solids and supports the concept of pre-operative oral nutrition using a special carbohydrate-rich beverage. On the other hand, coronary procedures require the use of intravenous contrast, which can precipitate acute renal impairment. It has been shown that proper hydration can reduce the risk of contrast-induced nephropathy. A review study suggests that the oral route is as effective as the intravenous route for volume expansion and reduction of contrast-induced acute kidney injury. A prospective study demonstrated that lack of fasting was not associated with a higher incidence of adverse events in children undergoing pre-procedural sedation in the emergency department. A recent clinical policy published by the American College of Emergency Physicians; has recommended (Level B), that procedural sedations in emergency departments should not be delayed based on fasting status.

Similarly, a recent retrospective study of 1900 patients in UK, demonstrated that patients do not need to be NPO prior to Percutaneous Coronary Intervention (PCI). Another study has demonstrated that reduced gastric pH (<2.0) and increased gastric volumes predisposed to pulmonary aspiration. Invasive procedures such as angiography and angioplasty both are associated with a small risk of adverse events. One such adverse event is vasovagal reaction which occurs in 3-4% of patients and may be exacerbated by depletion of volume as seen in the fasted state .

Current status at the University Health Network UHN policy requires patients to fast for both solids and liquids for a minimum of 4 hours before cardiac catheterization.

The investigators explore a fasting protocol that is different from current UHN policy

Introduction, background and justification for the study:

UHN policy requires patients to fast for both solids and liquids for a minimum of 4 hours before cardiac catheterization.

The investigators explore a fasting protocol that is different from current UHN policy and have involved staff from both the cardiothoracic surgery and anesthesiology teams, who will also act as a safety monitor and be part of the Data Safety Monitoring Board to ensure that participants are safe from harm or adverse effects.

Currently there is no published data on the association between fasting state and peri-procedural vasovagal symptom reduction or procedural satisfaction.

Hypothesis:

A more liberal fasting protocol (fasting > 4 hours for solid, but encouraging oral clear fluids up to 1 hour prior to the procedure) is associated with a lower incidence of peri-procedural vasovagal complications than current standard fasting protocol (> 4 hours for both solids and fluids)

Methods and experimental design:

This is a prospective single-blind randomized pilot study. The Cardiac Interventionists involved in the procedure will be blinded to randomization. All patients undergoing cardiac invasive procedures will be screened for eligibility. The participants will be randomised to 2 groups (eligibility criteria and outcome measures are mentioned in a different section).

Study Groups Group 1 - Control Group: Participants will be fasted according to current standard practice at UHN (a minimum of 4 hours of fasting period for both liquids and solid food).

Group 2 - Intervention group: Participants will be allowed (and encouraged) to drink clear fluids up to 1 hour before the procedure. Solid foods will be allowed up to 4 hours before the procedure which is current standard practice at UHN.

Enrolment and randomization:

Participants who qualify for the study will be approached in person prior to (if in-patient) or on the day of the procedure (if ambulatory) to obtain written informed consent prior to randomization.

A verbal explanation and written information in the form of the patient information sheet will be given to participants. They will be approached by co-investigators who are not involved in their care and given at least 4-24 hours to consent for the study. They will have as much time as they need to consider the study. They will also have the opportunity to discuss it with their family, friends and family doctor.

They will be given contact details of the on-site research team including the study doctors and nurses who will be able to answer any of their queries at any point during the study. They will be notified that they are not obliged to participate in the study and if they do decide to take part and change their mind at any point they can withdraw from the study unconditionally and their withdrawal will not affect their future care.

Vulnerable groups will not be participating in this research hence no special measures will be taken for their recruitment. Participants will also be informed of any potential safety concern that may arise during the study and will be advised about further treatment options. Wherever possible the Hospitals translation service will be used to offer translation of the consent form to patients who do not have English as their first language. Other individuals, who require specialist communication such as the visually impaired or those who suffer from deafness will wherever possible, be accommodated with the hospitals on-site services.

Throughout the study the participant's identity will be protected and will not be disclosed outside the Hospital in keeping with the University Hospital Network (UHN) Patient Health Information (PHI) policy. At the beginning of the study the investigators will receive an identification log to enable them to record patient study pseudonymised identification numbers. This record will remain at the central research offices at the participating centers and will act as a reference document for the PI. Data from the case report forms (CRFs) will be stored on an onsite computer. The hard copy CRFs will be kept in the research doctor's office -the persons able to access the case report forms will be the PI and the cardiology research doctors and nurses delegated for this study purpose.

Follow up:

Participants will be requested to return for one blood test between day 3 and day 5 post- procedure. To and from public transport cost will be provided to the patient and one accompanying person if needed. A telephonic follow up will also be undertaken at one week to ensure no adverse events have occurred.

Baseline investigations/Information:

At the time of the procedure , the investigators will obtain and record the following:

Pre-procedural Information

1. Pre-procedure investigations (Hemoglobin, Urea, Creatinine, eGFR)
2. Patient demographics (Diabetes Mellitus {DM}, hypertension {HTN}, renal impairment, peripheral vascular disease {PVD})
3. Index admission diagnosis (NSTEMI, Chronic stable angina)
4. Weight, height and Body Mass Index (BMI)
5. Medications on admission

Procedural and post-procedural information will be recorded, including:

1. Type of procedure
2. Route (access site-femoral or radial) of procedure
3. Intra-procedural details (sedation, analgesia, complications, devices-used)
4. Procedural and post-procedural outcomes(Success, in-hospital complications, discharge time and date, complications including mortality and aspiration pneumonia)
5. Patient satisfaction survey
6. Post-procedural creatinine
7. Post-procedural telephonic call one week from date of procedure Statistical analysis Demographic and procedural variables will be presented as percentage (categorical variable) or mean ± SD (continuous variable). Comparison of demographic and procedural variables between the two groups will be performed by chi-square or Fisher's exact test for categorical variables and student's t test for continuous variables. Statistical analysis will be performed using SPSS version 22. Randomization will be performed by systematic random sampling by utilizing an online computer generated random number assignment tool.

Sample size calculation:

Sample size was calculated based on proportion and effect size. A total sample size of 240 patients (120 patients in each arm) would have an 80 % power to detect a 1.0% incidence of vasovagal reaction in the intervention arm (for an α of 0.05).

Funding:

This study is being funded by the UHN Innovation Committee. Once the outcomes of the pilot study are available and if safety endpoints are accomplished, , the investigators will consider conducting a similar multicentre study.

Ethics:

All aspects of Good Clinical Practice will be adhered to. Patient confidentiality will be maintained as per the data protection policy including anonymising data. Ethical approval has been obtained from the REB through routine channels (CAPCR).

Inclusion Criteria:

1. Ability to give written informed consent
2. Diagnostic coronary angiography and coronary interventions (both elective and stable Acute Coronary Syndrome {ACS} patients).
3. ≥ 18 years of age

Exclusion Criteria:

1. Patients who are intubated

2. Patients unable to give informed consent

3. Patients presenting with an acute unstable condition, including:

   1. STEMI
   2. unstable ACS

4. Patients with a history of or at risk for aspiration pneumonia

   • stroke
   • dysphagia
   • severe gastroesophageal reflux disease

5. Patients with known or anticipated difficult airway

6. Patients who request to be allotted to a particular arm of the study

7. Patients who are temporary transfers from other hospitals