Is your dentist capable of handling a life-threatening emergency? If you do an internet search for “medical gas accidents,” you might not come across too many, but common errors do occur on the dental side of health care. 

One such incident happened in March 2009, when a Tonganoxie, Kansas, teenager was seriously injured due to an improperly installed medical gas system. Other accidents have happened when dentists perform procedures that are above and beyond what their facilities are designed to handle. 
The following are the categories as defined by 2012 NFPA 99, Chapter four, which provides guidance for the medical gas designer when designing a medical gas system in a healthcare facility such as a dental office. My comments are italicized:

4.1 Building System Categories. Building systems in healthcare facilities shall be designed to meet system Category 1 through Category 4 requirements as detailed in this code.

4.1.1 Category 1. Facility systems in which failure of such equipment or system is likely to cause major injury or death of patients or caregivers shall be designed to meet system Category 1 requirements as defined in this code.

4.1.2 Category 2. Facility systems in which failure of such equipment is likely to cause minor injury to patients or caregivers shall be designed to meet system Category 2 requirements as defined in this code. If a dental office performs procedures using anesthesia, it will typically fall into this category, which in turn qualifies it for Category 1. 

4.1.3 Category 3. Facility systems in which failure of such equipment is not likely to cause injury to patients or caregivers, but can cause patient discomfort, shall be designed to meet system Category 3 requirements as defined in this code. A typical dental office falls under this category.

4.1.4 Category 4. Facility systems in which failure of such equipment would have no impact on patient care shall be designed to meet system Category 4 requirements as defined in this code. 

4.2 Risk Assessment. Categories shall be determined by following and documenting a defined risk assessment procedure.

For a long time, dental offices have fallen into the Category 3 classification based on the procedures and sedation levels they use. The following are definitions of the levels of anesthesia and levels of sedation / analgesia as described by 2012 NFPA 99:

3.3.61 General Anesthesia and Levels of Sedation/Analgesia.

3.3.61.1 General Anesthesia. A drug-induced loss of consciousness during which patients are not arousable, even by painful stimulation. The ability to independently maintain ventilatory function is often impaired. Patients often require assistance in maintaining a patent airway, and positive pressure ventilation may be required because of depressed spontaneous ventilation or drug-induced depression of neuromuscular function. Cardiovascular function may be impaired. 

3.3.61.2 Deep Sedation/Analgesia. A drug-induced depression of consciousness during which patients cannot be easily aroused, but respond purposefully following repeated or painful stimulation. The ability to independently maintain ventilatory function may be impaired. Patients may require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained. 

3.3.61.3 Moderate Sedation/Analgesia (Conscious Sedation). A drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patient airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained. 

3.3.61.4 Minimal Sedation (Anxiolysis). A drug-induced state during which patients respond normally to verbal commands. Although cognitive function and coordination may be impaired, ventilatory and cardiovascular functions are unaffected. 

A dentist may administer either a local analgesic (local shot) or a painkiller (pill-dosing) prior to performing minor procedures. At this point, the dentist may use a drill and perform work including crowns, braces, cleanings and minor extractions. 

However, when it comes to performing oral and maxillofacial procedures during which general anesthesia is administered, the dental office may not be designed with the required safety measures built in. Those procedures utilizing general anesthesia actually fall under a Category 1 facility.

Dentists who perform these types of procedures may or may not have the required safety measures built into their facilities to handle anesthetized patients. Sometimes dentists bring in an anesthesiologist and a portable anesthesia cart, but this is when most of the problems occur since the facility still does not meet the ventilation, medical gas, alarm, monitoring, electrical or staff requirements. 

As designers, we need to ask questions about procedures being performed in the facility, how they will be performed, and what levels of anesthesia and sedation will be used so we can install the required systems. Inspectors of the facility should request the same documentation during their initial and follow-up visits to make sure the facility remains in compliance. 

John Gregory, mechanical coordinator in HDR’s Phoenix architecture studio, has 28 years of experience in medical gas systems design and inspections, process piping, plumbing, and fire protection systems design for multiple business classes. He coordinates projects with HDR’s clients and supervises team members on plumbing, process piping, fire protection and medical gas systems. Gregory is a certified medical gas inspector NITC 6020. He serves on the NFPA 99 Technical Committee for piping and installation, and he is a co-chair of the P.I.P.E. Medical Gas Committee in Arizona. Gregory’s unique skills are an asset to every team in which he is involved. He can be reached at john.gregory@hdrinc.com.