Vitamin C to prevent pulmonary complications in cardiac surgery

Approved 07/07/2022, Ethics Committee of Medical Faculty UC Belgrade (8th Dr Subotić St, Belgrade, 11000, Serbia; +381 (11) 3636300; mf.bg@med.bg.ac.rs), ref: 1322/VII-24

1. The severity of postoperative pulmonary complications (PPC) measured using the modified Kroenke’s scoring tool daily at baseline, and during the first 7 postoperative days
2. The incidence of PPC measured using the modified Kroenke’s scoring tool daily, at baseline and during the first 7 postoperative days

The secondary outcome measures are grouped as follows:

1. Pulmonary Oxygenation and Ventilation:
1.1. Horowitz Index: PaO2/FiO2 – is calculated by using PaO2 values from the ABG analysis and FiO2 from the oxygen delivery device, 48 hours after the surgery
1.2. Alveolar–arterial Gradient: A-aDO2 – is directly recorded from the ABG analyzer, 48 hours after the surgery
1.3. Time Spent on Mechanical Ventilation – is calculated for each patient before the transfer from the ICU as the total number of hours spent on mechanical ventilation, from the time of intubation (or initiation of non-invasive ventilation) to the time of extubation (or discontinuation of non-invasive ventilation).

2. Inflammatory Markers: (Procalcitonin, C-reactive Protein, Leucocytes, Neutrophils, Lymphocytes, Sedimentation Rate, Fibrinogen, Albumin, D-dimer, and Ferritin) all measured from blood samples processed in the clinical hematological and biochemical laboratory following standard hospital laboratory protocols and recorded at baseline, 0, 24, 48, 72 and 96 hours after the surgery

3. Renal Function: (Glomerular Filtration Rate (GFR) < 60mL/min, Creatinine, Urea) all measured from blood samples processed in the clinical hematological and biochemical laboratory following standard hospital laboratory protocols and recorded at baseline, 0, 24, 48, 72 and 96 hours after the surgery

4. Non-pulmonary Postoperative Complications: (Postoperative nausea and vomiting -PONV, delirium, transfusion, acute renal failure, wound infection, cardio-pulmonary-resuscitation – CPR) all assessed as an episode (event) after being assessed and documented by the blinded attending practitioner and recorded using the medical documentation tool before the discharge from the hospital

5. Postoperative Organ Dysfunction:
1. SOFA Score - Sequential Organ Failure Assessment (SOFA) score calculated and recorded by a blinded assistant 48 hours after the surgery
2. ASA/SOFA Ratio - The American Society of Anesthesiologists (ASA) score is calculated and recorded by a blinded assistant at baseline and ASA/SOFA ratio is calculated upon discharge from the ICU

6. Intensive Care Unit (ICU) Parameters:
6.1. Re-admission – recorded at the time of occurrence and counted before the hospital discharge, as any new episode (event) of ICU admission after the initial ICU discharge, regardless of medical reason and time spent in the ICU after re-admission.
6.2. Length of Stay - calculated as the total number of hours spent in ICU for each patient upon discharge from the ICU, measured from any (initial and subsequent) admission to ICU to discharge from the ICU

7. Hospital Parameters:
7.1. Length of Stay - calculated as the total number of days spent in the hospital and recorded upon discharge from the hospital measured as the number of days from admission to discharge from the hospital
7.2. Hospital Mortality – defined as death from any cause during the hospital stay and recorded upon discharge from the hospital