Just checking, did you mean to put something like "common" in your first sentence? Sudden minor episodes are not uncommon, and with a baby of 27 weeks' gestation not totally unexpected. By which I mean not breathing, quite common as the brain is immature and they just "forget" - it's hard work too! ( They can be given caffeine to stimulate breathing, you might be interested to know). You virtually always have a reason for this. Also, collapse to the point of needing cardiac massage is not common at all, as the overwhelming majority of problems are respiratory, so once you sort that out all is well.
One more thing! The gestation is extremely important. Not just at birth, but the equivalent as they get older. So a healthy baby born at 27 weeks who is now 6 weeks old is looked at as a 33 weeker, who should be beginning to feed normally etc.