The field of anesthesia has been exemplary in the pursuit of ensuring patient safety perioperatively. Critical to this pursuit is the equipment we use. Perhaps then, it is ironical that the safety of containers for volatile anesthetic agents is yet to be confirmed.
In this report we highlight the need for safety standards for bottles of volatile liquids, and suggest a possible solution to a not so uncommon problem.
A lymph node biopsy under monitored anesthesia care was performed for an elderly male with ischemic heart disease. During the procedure, the attending anesthesiologist noted that the isoflurane vaporizer was nearly empty. Since the subsequent surgical case was scheduled under general anesthesia, the operation room (OR) technician was instructed to refill the vaporizer immediately. Unfortunately, while bringing the bottle of isoflurane from the OR store-room, she tripped against the OR door and fell headlong. Although the technician suffered no bodily harm, the fate of the bottle she had been carrying was very different. Its shards were scattered about the OR floor and the unmistakable odor of isoflurane permeated every corner of the theater.
The OR doors were immediately thrown open, with the intention of diluting and dispelling the vapor. The surgeons were urged to finish the procedure as fast as possible and the surgery was completed within the next 10 minutes. No ill effects because of the inadvertent exposure to isoflurane vapor molested any of the theater personnel, or complained of by the patient.
Events like this can happen in any operating room as most volatile anesthetics are stored in glass bottles. Safety guidelines for further management of such events are already in place.1 In our case, neither the patient nor any of the operating room staff had suffered untoward effects. A likely explanation to this is that the entire vaporization produced by the spurt of a full bottle of isoflurane is insufficient to reach any significant concentration in the atmospheric air in an average operating theater. Considering a 250 ml bottle of isoflurane, 49000 ml of vapor would be produced at OR temperature (21 °C), and the size of the theater being approximately 16 feet by 16 feet with a ceiling height of 10 feet, a concentration of 0.0675 v/v% is likely to be produced should the vaporization occur instantly and the vapor spread uniformly in the room (2560 ft = 72491127.58 ml).
As air changes in the theater take place at 20–30 times an hour, the isoflurane vapor would be rapidly diluted even further. Also, since isoflurane is denser than air, its ascent up to the circumambiency of the operating table would likely be retarded. In fact the shards of glass did pose a greater nuisance than the anesthetic gas itself, till they were uneventfully swept off into a plastic container and suitably disposed as per the guidelines from American Association of Nurse Anesthetists.1
Our departmental inquiry revealed that in the past decade several such instances had occurred resulting in unnecessary spillage of isoflurane and prior to this incident there were multiple instances with halothane spillage. Such a ‘theatrical spill’ although mercifully rare is hardly an isolated event. Even utmost care while handling isoflurane bottles may not always succeed in preventing such incidents. Currently, containers for fluorinated anesthetics are made of amber colored ‘Type III’ glass.2 Perhaps the simplest way around this problem is to store isoflurane in unbreakable containers. One alternative is storage of isoflurane in metal container made of aluminum or other metals in which isoflurane is known to remain stable. The main limitation with this handling is that the deposit of the volatile anesthetic in the bottle can hardly be assessed. To overcome both these problems, we suggest the development of glass bottles encased in a rigid external transparent plastic sheath, which would reduce the likelihood of the glass bottle from shattering on impact. This would not only reduce spillage of the anesthetic but also minimize the risk of glass shards being scattered (Fig. 1).
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