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Treatment and the treatment process

Transplant day

Transplant day — "day zero" — is when stem cells are given into a vein. It is like an ordinary blood transfusion and is often calmer than people expect.

Last updated: ~2 min read
In a calm, dim transplant room, a small stem cell bag glowing red and gold hangs on an infusion stand.
Figure 1.Stem cells are dripped into a vein.

01Short answer

Before a stem cell transplant comes conditioning — high-dose chemotherapy and sometimes radiotherapy. Then comes "day zero": the stem cells (from a donor — allogeneic — or your own cells collected earlier — autologous) are dripped in through a central line. It is not an operation, it is painless and usually takes from a few minutes to a few hours. Identity and bag details are checked carefully first, and medicines may be given to prevent reactions. Because of the preservative (DMSO) in frozen cells, you may notice a garlic taste and a distinctive smell in the room. After that, days are counted "+1, +2…"; the cells settle in the bone marrow and usually start making new blood cells within a few weeks — this is called engraftment.

02Simple explanation

A new start. Stem cells are dripped into a vein.

Painless. It is like a blood transfusion.

They find their way. The cells travel to the bone marrow by themselves.

Waiting. Engraftment usually takes a few weeks.

03Scientific explanation

Graft types: peripheral blood stem cells (most common), bone marrow or cord blood; allogeneic or autologous. In allogeneic transplant the donor’s and recipient’s blood groups may differ, in which case the product is processed further.

Infusion reactions: with frozen products, DMSO-related nausea, flushing, slow heart rate and blood pressure changes; premedication and monitoring of vital signs reduce these risks. With large-volume or ABO-incompatible products, haemolysis risk is watched.

Engraftment is usually recorded when the absolute neutrophil count passes a set threshold on consecutive days; platelets may recover later. Infection prophylaxis and transfusions continue in this period, and in allogeneic transplant, GVHD prophylaxis.

04What happens in the body?

How does the infusion go?

The stem cell bag hangs on a stand and is connected to your central line. A nurse stays with you, checking blood pressure, pulse and oxygen.

How do the cells find their way?

Stem cells carry special "address" molecules on their surface; from the bloodstream they settle in the bone marrow and begin to multiply.

Small glowing stem cells travel along the bloodstream and settle into a honeycomb-like bone marrow space.
Figure 2.The cells find their own way to the bone marrow.

An emotional day

Many people call it their "second birthday". You can share a quiet, memorable moment with loved ones while following infection rules.

Soft sunrise light comes through the window of a quiet single hospital room with a neatly made bed.
Figure 3.For many, day zero is a new beginning.

05Day zero and after

A simplified outline.

Conditioning ends — There may be a day or two of rest.1Conditioning endsThere may be a day or two of rest.
Checks — Identity and product.2ChecksIdentity and product.
Infusion — Under observation.3InfusionUnder observation.
Waiting for engraftment — Days are counted.4Waiting for engraftmentDays are counted.
Protective measuresAgainst infection and reactions.
EngraftmentNew blood cells appear.
A few weeksCounts recover.

06What to expect on transplant day

StageWhat happensNote
PreparationPremedication, vital signsSometimes fluids are given
InfusionCells dripped inMinutes to hours
Straight afterObservationGarlic taste and smell possible
Following daysCounts are lowInfection rules, transfusions
EngraftmentNeutrophils recoverUsually within a few weeks

* Timings vary with the type of transplant and the centre; your team will explain your plan.

07Key terms

Day zero
The day stem cells are given.
Conditioning
Intensive treatment before transplant.
Allogeneic
Cells from a donor.
Autologous
The patient’s own cells.
Engraftment
When new cells start making blood.
DMSO
A substance that protects frozen cells.

08Key points

  • Transplant day is a painless infusion.
  • Everything is double-checked for safety.
  • The unusual taste passes.
  • Infection risk is high in the following weeks.
  • Engraftment usually takes a few weeks.
  • Tell the nurse about any new symptom.

09Frequently asked questions

Is the infusion painful?

No, it is like a blood transfusion; sometimes there is nausea or a warm feeling.

Can my family be with me?

It depends on the centre’s rules; infection protection matters.

What if the cells don’t engraft?

This is rare; the team watches closely and takes further steps if needed.

When can I go home?

Usually once counts recover and you are stable; your team decides when.

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

  1. Is the infusion painful?

  2. Can my family be with me?

  3. What if the cells don’t engraft?

  4. When can I go home?

My questions

12Sources

  1. NHS. How a stem cell or bone marrow transplant is done
  2. NHS. Stem cell or bone marrow transplants
  3. National Cancer Institute (NCI). Stem Cell and Bone Marrow Transplants for Cancer
  4. ICUsteps. Guide to intensive care: introduction
  5. ICUsteps. Guide to intensive care: your time in the ICU
  6. MedlinePlus (U.S. National Library of Medicine). Critical Care
  7. Society of Critical Care Medicine (SCCM). Patient and Family Resources
  8. Journal of Clinical Oncology, 2013. Outcomes of critically ill patients with hematologic malignancies: prospective multicenter data from France and Belgium
  9. Critical Care Medicine, 2017. Guidelines for Family-Centered Care in the Neonatal, Pediatric, and Adult ICU
  10. Critical Care Medicine, 2012. Improving long-term outcomes after discharge from intensive care unit: report from a stakeholders’ conference
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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