limit of viability

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limit of viability by Mind Map: limit of viability

1. factors affecting the survival rate in extremely premature infants (less than 26 weeks of gestation)

1.1. gestational age

1.1.1. a challenge to determine accurately

1.1.2. margin of error from a few days if it was based on very early ultrasound accurate assessment of age based on physical appearance is only possible in the first 2 weeks to 2 weeks if based on last menstrual period date and/or second trimester untrasound a newborn believed to be 23 weeks can be under 22 or more than 24! you can't tell by physical examination

1.1.3. it is determined in the case of in vitro fertilisation

1.2. birth weight

1.2.1. the more the better

1.3. gender

1.3.1. female sex has better chance

1.4. plurality

1.4.1. singleton birth has better survival

1.5. use of antenatal glucocorticoids

1.5.1. it is associated with increased survival rate for infants if administered to their mothers in preterm labor

2. Definition

2.1. the stage of fetal maturity that ensures a reasonable chance of extrauterine survival

2.1.1. we need it to determine when to avoid costly and painful operations in infant that do not have a survival chance

3. Ethical questions

3.1. should resuscitation and intensive care measures - including intubation, chest compression, epinephrine, and mechanical ventilation - be initiated in the delivery room?

3.1.1. impact of initial management not providing intensive care may result in near 0 survival, so the question is weather the intensive care affects survival significantly, not weather the infant can survive on his own

3.2. are such measures impermissible, optional, or obligatory?

3.2.1. if the prognosis is good - based on date about mortality and morbidity - resuscitation is obligatory

3.2.2. if the prognosis is very poor and survival is not likely then resuscitation is impermissible

3.2.3. if the prognosis is uncertain then it should be up to the informed parents

3.3. how much of a say should parents have?

3.4. what are the decisions based on?

3.5. is it ethically permissible to stop things like mechanical ventilation after they are started?

3.5.1. yes. some thought that it's not, but if it was permissible to start it for a reason then we can stop it for a reason too

3.6. a rational approach will be aided with these questions

3.6.1. what are the strengths and weaknesses of the data?

3.6.2. what are the relevant ethical issues and principles? the right to life beneficence the right to mercy (avoiding pain) non-maleficence the right for the parents for information to make informed decisions, but their authority may be overridden with child's rights Autonomy justice

3.6.3. what are the recommendations of professional organisations and what are they based on?

4. Long term morbidity should be considered

4.1. cognitive impairment, cerebral palsy, visual impairment, hearing impairment, and learning difficulties

4.2. but still you cannot predict them very accurately

5. summery and guideline

5.1. the dilemma is: we can't be 100% accurate

5.1.1. if treatment is given to all This will be good for infants that have a good survival chance. They will be supported and treated to live normally It will be harmful for infants that have no chance of survival by making them suffer by prolonging death time, or may make them live with severe disability (poor quality of life)

5.1.2. if the treatment is withheld from all it will be harmful for those infants that have a chance to survive with treatment, so they will be "killed" by withholding treatment it will be good for those infants that have no chance of survival, because it reduces their suffering

5.1.3. so in either cases we will do harm!

5.2. up to date guideline to management approach

5.2.1. below 22 weeks of gestation - no resuscitation

5.2.2. 22 weeks to 22 and 6 days resuscitation offered if there's a chance of survival based on available information NICHD calculator provided ONLY IF requested by the parents

5.2.3. 23 weeks to 23 and 6 days resuscitation offered, provided on request

5.2.4. 24 weeks to 24 and 6 days resuscitation offered, provided on request unless chance of survival without neurological damage is more than 50%, then it's provided

5.2.5. 25 weeks and higher resuscitation provided