By Dr. Apurba Kumar Sarma, MCh CVTS | Cardiac Surgeon, Tulip Mediworld Superspeciality Hospital, Guwahati
Quick Takeaways
- Bypass surgery follows a clear, well-established sequence. Knowing what happens at each step removes most of the fear around it.
- You will be completely asleep under general anaesthesia for the entire procedure. You will feel nothing.
- The heart-lung bypass machine temporarily takes over the work of your heart and lungs so the surgeon can operate on a still, quiet heart. This is safe, routine, and widely used in cardiac surgery worldwide.
- Most patients are moved out of the ICU within 24–48 hours of an uncomplicated bypass surgery. The majority go home within 5–7 days.
- The night before surgery, speak to your surgical team about any concerns. There are no foolish questions when it comes to your heart.
Every patient I have operated on in over 25 years as a cardiovascular and thoracic surgeon has asked me some version of the same question before their bypass surgery: “Doctor, what exactly is going to happen to me?”
It is a completely reasonable question. Bypass surgery – formally called Coronary Artery Bypass Grafting, or CABG – is a major operation. I have performed more than 7,000 heart surgeries, and I still make it a point to sit with every patient the evening before their procedure and walk them through exactly what will happen the following day. Because in my experience, the single biggest source of pre-surgery anxiety is not the surgery itself – it is not knowing what to expect.
This article does what that conversation does. I want you – or the family member you are reading this for – to go to sleep tonight knowing precisely what tomorrow looks like. Step by step, from the night before to waking up in the ICU.
Your admission team will give you specific instructions, but here is what the evening before bypass surgery generally involves.
Fasting from midnight. You will be asked not to eat or drink anything after midnight – including water, unless instructed otherwise. This is a safety precaution required for general anaesthesia. An empty stomach significantly reduces the risk of complications when anaesthesia is induced.
Antiseptic bath. You will be asked to bathe with an antiseptic wash (usually chlorhexidine) the night before and again on the morning of surgery. This reduces the risk of surgical site infection.
Medications. Some of your regular medications will be continued as usual; others – particularly blood thinners such as aspirin or clopidogrel – may be paused several days before surgery. Your surgical team will give you a clear list of what to take and what to skip. Follow this exactly. If you are unsure, call the hospital rather than guessing.
What to bring. Comfortable clothes for recovery, essential personal items, and a list of all current medications. Leave valuables at home. Your family will need to know where to wait and when to expect updates – the nursing team will guide them.
Emotional preparation. This is the part that gets less attention than it deserves. It is entirely normal to feel worried, unsettled, or even frightened the night before surgery. These feelings do not mean something is wrong. What helps most patients is a combination of honest information (which this article is meant to provide) and knowing that the team performing their operation has done this hundreds of times. Speak to the nurses on the ward if you have concerns. They are there through the night.
You will be taken to the pre-operative preparation area – sometimes called the “holding area” – a few hours before your scheduled surgery time.
What happens here:
Meeting the anaesthesiologist. Before you are taken to the operating theatre, your cardiac anaesthesiologist – the specialist who will keep you safely asleep throughout the procedure – will speak with you. This is your opportunity to ask any final questions. They will confirm your medical history, current medications, and any allergies, and explain what general anaesthesia will feel like. The answer to that last question is simple: within seconds of the anaesthetic being given, you will feel a gentle heaviness, and then nothing at all until you wake up in the ICU.
You will not be conscious for any of this. But many patients tell me they find it reassuring to know exactly what was happening while they were asleep – so here is a straightforward account.
The surgical team. A bypass surgery involves a cardiac surgeon (and typically a surgical assistant), a cardiac anaesthesiologist, a perfusionist (the specialist who manages the heart-lung bypass machine), and scrub and circulating nurses. At Tulip Mediworld, this team works together with a rhythm built on hundreds of shared procedures.
The sternotomy. Once you are under general anaesthesia, the surgeon makes an incision along the centre of your chest and carefully divides the sternum (breastbone) to access the heart. This is called a median sternotomy. At the end of surgery, the sternum is wired back together with stainless steel wires that remain permanently in place – they cause no problems and will not set off airport metal detectors.
Harvesting the graft vessels. Before bypassing the blocked arteries, the surgeon needs healthy blood vessels to use as the bypass grafts. The two most commonly used are:
Going on bypass – the heart-lung machine. This is the step patients ask about most. The heart-lung bypass machine (also called cardiopulmonary bypass, or CPB) is a device that temporarily takes over the pumping and oxygen-delivering functions of your heart and lungs. Tubes are inserted into the large blood vessels entering and leaving the heart, and your blood is routed through the machine – which oxygenates it and circulates it through your body – while the surgeon works on a still, quiet heart. Without this machine, operating on a beating heart for an extended period would be far more difficult. The machine has been used safely in cardiac surgery since the 1950s and is operated throughout your procedure by a trained perfusionist. Per Cleveland Clinic protocols, the patient’s body temperature is often cooled during bypass to reduce the heart’s metabolic needs and protect it during this period.
Creating the bypasses. The blocked section of each coronary artery is bypassed by stitching one end of the graft vessel above the blockage and the other end below it, creating a new route for blood to flow around the obstruction. If you need three bypasses, this is called a “triple bypass,” or triple-vessel CABG. The number of bypasses depends on how many arteries are significantly blocked – not on how ill you are.
Coming off bypass. Once all the grafts are in place, the heart is rewarmed gently. In most cases, the heart begins beating on its own again as it warms up. If it does not restart spontaneously, a brief controlled electrical shock restarts it – this is routine and does not indicate a problem. The bypass machine is gradually withdrawn as the heart resumes its normal function, and the surgeon checks each graft to confirm good blood flow before closing.
Closing. The sternum is wired back together, the muscles and skin are closed in layers, and small drain tubes are placed in the chest to remove any fluid that accumulates in the first hours after surgery.
A straightforward bypass surgery typically takes 3 to 6 hours from the time anaesthesia begins to when you are moved to the ICU. More complex cases – such as redo bypass surgery or procedures with additional valve work – may take longer.
| Time | What Is Happening | What You Experience |
|---|---|---|
| Night before | Fasting, antiseptic wash, final medication review | Awake – rest and emotional preparation |
| Early morning | Arrival, IV line, pre-op preparation, sedative | Awake, then gently sedated |
| Pre-op | Anaesthetic induction | Counting backwards – then nothing |
| Hour 1 | Sternotomy, graft harvesting | Completely unconscious |
| Hours 1–3 | Bypass machine on, grafts sewn | Completely unconscious |
| Hours 3–5 | Off bypass, heart restarted, closure | Completely unconscious |
| Post-op | Moved to cardiac ICU | Beginning to wake up |
The first thing most patients notice when they begin to regain consciousness is the breathing tube in their throat – called an endotracheal tube. This tube was placed to manage your breathing during surgery and connects to a ventilator. It is uncomfortable and prevents speaking, but it is temporary. In most uncomplicated cases, the breathing tube is removed within 2 to 6 hours of arrival in the ICU, once you are breathing adequately on your own. The nursing team will tell you when it is coming out, and it is removed very quickly.
You will also notice:
The ICU team will speak to you regularly and explain everything they are doing. You may feel confused or disoriented initially – this is normal and temporary, particularly in the first 12–24 hours.
While you are in surgery, your family will be waiting. This is one of the hardest parts of the entire experience – not for the patient, but for the people who love them.
At Tulip Mediworld, families are kept informed by the nursing and surgical team. Once surgery is complete, the surgeon will speak directly to the family to explain how the procedure went and what to expect next. This conversation typically happens within 30–60 minutes of you being moved to the ICU.
Encourage your family to ask questions when they speak to the surgical team. No question is too basic. Understanding what happened during surgery helps families support the patient’s recovery more effectively.
No. You will be under general anaesthesia from the moment it is induced until the surgical team wakes you up in the ICU. General anaesthesia means complete unconsciousness – you will have no awareness, no sensation, and no memory of the procedure. The cardiac anaesthesiologist monitors you continuously throughout the operation to keep you safely asleep and to manage all your body’s functions while the surgeon works. Mayo Clinic describes general anaesthesia as one of the most closely monitored states in medicine.
Not during the operation – you are completely unconscious. After surgery, there is discomfort at the sternotomy (chest incision) and, if a leg vein was used, at the harvest site on the leg. This discomfort is well managed with pain medications in the ICU and ward. Most patients describe it as manageable – a soreness and tightness rather than sharp pain – and it diminishes progressively over the first two weeks. By six weeks, the vast majority of patients have returned to comfortable daily activity. Your team will guide you on safe pain management at every stage of recovery.
A standard bypass procedure typically takes 3 to 6 hours from the time anaesthesia is started. This includes time for preparation, graft harvesting, the bypass itself, and closure. Complex cases – those requiring redo bypass surgery, additional valve procedures, or involving significant arterial calcification – may take longer. Your surgeon will give you a specific estimate based on your individual case. The length of the operation is not a direct indicator of how the surgery is going; some complex, successful procedures simply take more time.
For uncomplicated bypass surgery, most patients are transferred from the ICU to a regular cardiac ward within 24 to 48 hours. Total hospital stay is typically 5 to 7 days for straightforward cases. Patients with additional medical conditions, or those who require closer monitoring, may stay longer – this is a clinical decision made in your best interest, not a sign that something went wrong.
Once on the ward, you will begin sitting up, standing, and taking your first careful steps – often on the same day you leave the ICU. This early mobilisation is deliberate and beneficial. Moving helps prevent complications, improves circulation, and accelerates recovery.
If you would like to understand the full recovery journey – from hospital discharge to returning to normal life – you can read our complete guide to life after bypass surgery on the Tulip Mediworld website.
The unknown is the hardest part of preparing for heart surgery. Now you know.
You know what will happen the night before, what the morning looks like, what the surgical team is doing while you are asleep, and what you will experience when you wake up. That knowledge does not eliminate every concern – but it does replace shapeless fear with manageable facts.
Bypass surgery is one of the most thoroughly researched and consistently successful procedures in all of modern medicine. In over 25 years of performing it – including thousands of cases at Tulip Mediworld Superspeciality Hospital in Guwahati, where patients from across Northeast India have received world-class cardiac care without leaving their home region – I have seen its power to restore lives that heart disease had quietly been taking away.
Your surgery team is ready. And now, so are you.
To speak with our team before your procedure, or to book a consultation, visit drapurbasarma.in or call 1800 890 4655. We are here for every question – before surgery, during recovery, and long after.
About the Author
Dr. Apurba Kumar Sarma, MBBS, MS (General Surgery), MCh (CVTS) is a cardiovascular and thoracic surgeon with over 25 years of experience and 7,000+ successful heart surgeries. He is the Founder, Chairman and Managing Director of Tulip Mediworld Superspeciality Hospital, GS Road, Rukmini Gaon, Guwahati, Assam — 781022. He is a Fellow of the Indian Association of Cardiovascular-Thoracic Surgeons and a Life Member of the Indian Medical Association.
This article is for informational purposes only and does not constitute medical advice. Please consult a qualified cardiac surgeon for evaluation and treatment specific to your condition.
