We are currently updating our website, and will have our new version online soon. Please check back later this fall.

Mailing List

Subscribe to the KT Canada mailing list




Once you have signed up, you will receive a confirmation email with your username and password. To activate your account, follow the instructions in the email.


Centre for Evidence-
Based Medicine

Completed Therapy Worksheet for Evidence-Based Neonatal Medicine


The Neonatal Inhaled Nitric Oxide Study Group. Inhaled nitric oxide in full-term and nearly full-term infants with hypoxic respiratory failure. N Engl J Med 1997; 336: 597-604.

Are the results of this single preventive or therapeutic trial valid?

  1. Was the assignment of patients to treatments randomised?
    And was the randomisation list concealed?
  2. Yes. Central telephone randomisation was used.
    Were all patients who entered the trial accounted for at its conclusion?
  3. And were they analysed in the groups to which they were randomised?
    Yes to both questions.
  4. Were patients and clinicians kept "blind" to which treatment was being received?
    Yes. Designated individuals who were not involved in the clinical care adjusted and monitored the study gases.
  5. Aside from the experimental treatment, were the groups treated equally?
  6. Were the groups similar at the start of the trial?

Are the valid results of this randomised trial important?

Your calculations:

Event rate for primary outcome (death by 120 days of age or initiation of ECMO) Relative Risk Reduction
Absolute Risk Reduction
Number Needed to Treat
64% 46% 28% 18% 6

Further analyses demonstrated that inhaled nitric oxide reduced the need for ECMO but did not decrease mortality: CER 55%, EER 39%, RRR 29%, ARR 16%, NNT 7 (95% CI 4 to 31).

Can you apply this valid, important evidence about a treatment in caring for your patient?

Do these results apply to your patient?

  1. Is your patient so different from those in the trial that its results can't help you?

How great would the potential benefit of therapy actually be for your individual patient?

  1. Method I: f
    Risk of the need for ECMO in your patient, relative to patients in the trial. Expressed as a decimal: 1

    = 7 / 1
    = 7
    (NNT for patients like yours)
  2. Method II: 1 / (PEER x RRR)
    Your patient's expected event rate if they received the control treatment: PEER:______

    1 / (PEER x RRR)
    = 1/________
    = __________
    (NNT for patients like yours)

Are your patient's values and preferences satisfied by the regimen and its consequences?

  1. Do your patient and you have a clear assessment of their values and preferences?
    This needs to be discussed with the parents of the patient; however, since inhaled nitric oxide is far less invasive than ECMO, chances are that parent would accept a recommendation to try inhaled nitric oxide first.
  2. Are they met by this regimen and its consequences?

Additional Notes

See commentary with the abstract in Evidence Based Medicine Sept/Oct. 1997 page 153

Continue to CAT