The Eyes Have It or Do They

Every now and then I come across an instance when I discover that something that I have known for some time truly is not as well appreciated as I might think.

Twice in my career I have come across the following situation which has been generalized to eliminate any specific details about a patient.  In essence this is a fictional story but the conclusions are quite real.

Case of the Flat Baby

A mother arrives at the hospital with severe abdominal pain and in short order is diagnosed with a likely abruption at 26 weeks gestational age. Fetal monitors are attached and reveal a significant fetal bradycardia with a prolonged period of minutes below 100 and sometimes below 60 beats per minute.  She is rushed to the OR where an emergency c-section is performed.

A live born infant is handed to the resuscitation team after cord clamping is stopped at 30 seconds due to significant cyanosis and no respirations.  After placing the infant in a polyethylene wrap and performing the initial steps of ventilation there is no respiratory effort and the baby is given PPV.  After no heart rate is noted chest compressions commence followed by intubation and then epinephrine when a heart rate while detected remains below 60.  The team gives a bolus of saline followed by another round of epinephrine and by 10 minutes a pulse of 80 BPM is detected.  While a pulse is present it remains borderline and the baby shows no sign of any respiratory efforts.

The care providers at this point have a decision to make about continuing resuscitative efforts or not.  One of the team members performs a physical exam at this stage and notes that the pupils are unresponsive to light with a 3 mm pupillary diameter.  The team questions whether based on this finding irreversible neurological damage has occurred.

Pupillary Reactions in Preterm Infants

It turns out that much like many organs in the body which have yet to fully mature the same applies to the eye or more specifically in this case the pupil. Robinson studied 50 preterm infants in 1990 and noted that none of the infants under 30 weeks gestational age demonstrated any reaction to light shone in the eye.  After 30 weeks the infants gradually realized this function until by 35 weeks all infants had attained this pupillary reaction to light.

iseyes.jpg

Isenberg in the same year when examining 30 preterm infants under 30 weeks noted that in addition to the lack of pupillary constriction to light, as the gestational age decreased the pupillary diameter enlarged.  The youngest infants in this study at 26 weeks had a mean pupillary diameter of 4.7 mm while by 29 weeks this number decreased to 2.9 mm.  This means that the smaller the infant the larger the pupillary size and given that these are also the highest risk infants one can see how the appearance of a “fixed and dilated pupil” could lead one down the wrong path.

Conclusion

Deciding when to stop a resuscitation is never an easy decision.  Add to this as I recently wrote, even after 10 minutes of resuscitation outcomes may not be as bad as we have thought; Apgar score of 0 at 10 minutes: Why the new NRP recommendations missed the mark.  What I can say and obviously was the main thrust of this piece is that at least when you are resuscitating an infant  < 30 weeks gestational age, leave the eyes out of the decision.  The eyes in this case “do not have it”.

 

 

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