Ball point pens are not all equivalent, suggests this emergency-medical study:
“Airflow efficacy of ballpoint pen tubes: a consideration for use in bystander cricothyrotomy,” David Owens, Ben Greenwood, Alistair Galley, Alun Tomkinson, Sarah Woolley, Emergency Medicine Journal, 2010;27:317-320. (Thanks to investigator @MsCelsius for bringing this to our attention.) The authors, at Princess of Wales Hospital, Bridgend, Wales, University Hospital of Wales, Cardiff, and Bristol Royal Infirmary, Bristol, UK, report:
OBJECTIVE To examine the suitability of commonly available ballpoint pens as a substitute emergency tracheostomy tube.
METHODS commonly available ballpoint pens were examined and compared against two standard cricothyroidotomy sets. The pens were evaluated for dimensions, speed of construction of a temporary tracheostomy tube and airway resistance with differing flow rates.
RESULTS Internal diameters of the pens varied considerably. Time taken to construct a temporary tube ranged from 3 to 170 s, and in the majority of pens the airway resistance increased dramatically as the airflow rate increased.
CONCLUSION Contrary to popular belief, the majority of ballpoint pens appear unsuitable for use as a substitute tracheostomy tube. In this study only two pens fulfilled the criteria for use: the Baron retractable ballpoint and the BIC soft feel Jumbo.
NOTE: Both of those recommended kinds of pens are now rather difficult to find (perhaps as a result of hordes rushing to stock up, after reading the study?)