B737-300 DEPARTING MSP HAD PAX ILLNESS AND MULTIPLE WX DELAYS. FORGOT TO NOTIFY MAINT OF A USED OXYGEN BOTTLE WRITE-UP.

Narrative

PUSHED BACK INITIALLY ON TIME FROM GATE. NEAR BLIZZARD CONDITION PREVAILED AT THE TIME. WE DE-ICED AND HEADED FOR TKOF. HAD TO RETURN TO GATE AFTER APPROX 40 MINS DUE TO FAILURE OF DE-ICE FLUID ON WINGS. JUST PRIOR TO ARR BACK AT THE GATE FLT ATTENDANT CALLED WITH MEDICAL EMER AND INDICATED THEY WERE USING SUPPLEMENTAL OXYGEN ON PAX THAT WAS FEELING FAINT. WE CALLED FOR PARAMEDICS TO MEET THE ACFT AT THE GATE. PAX DEPLANED WITH THE PARAMEDICS AND WAS FEELING MUCH BETTER AT THAT TIME. THE BLIZZARD CONTINUED AND GND CREWS WERE WORKING HARD TO KEEP THE ARPT OPEN. THE CAPT AND DISPATCH DECIDED TO DELAY THE FLT DUE TO THE INTENSITY OF SNOW AND RAPIDLY CHANGING RWY CONDITIONS THAT WERE DIFFICULT TO ASSESS. THE CAPT AND MY ATTN WAS NOW DIRECTED TOWARD THE REMAINING PAX AND CUSTOMER SVC. WE BOTH YIELDED MANY QUESTIONS; DEALT WITH BAG ISSUES; ETC; AND TRIED OUR VERY BEST TO KEEP THE SIT UNDER CTL. AFTER ALMOST 5 HRS AND LIGHT SNOW FALLING NOW; THE CAPT AGAIN DECIDED TO PUSH BACK; DE-ICE AND ATTEMPT TO TAKE OFF. THIS TIME TKOF WAS SUCCESSFULLY ACCOMPLISHED AND IT WASN'T UNTIL FL180 THAT I REMEMBERED THE OXYGEN BOTTLE WRITE-UP WAS NEVER ENTERED INTO ACARS. BOTH THE CAPT AND I HAD INADVERTENTLY FORGOTTEN TO WRITE IT UP. UPON REACHING CRUISE ALT I SENT THE DISCREPANCY TO MAINT AND THE BOTTLE WAS REPLACED IN ZZZ.