From the Department of Anesthesiology, Texas A&M University Health Science Center College of Medicine, Scott & White Hospital, Temple, Texas.
Anesth Analg. 2014 Apr;118(4):772-5. doi: 10.1213/ANE.0000000000000133.
Operating room fires are sentinel events that present a real danger to surgical patients and occur at least as frequently as wrong-sided surgery. For fire to occur, the 3 points of the fire triad must be present: an oxidizer, an ignition source, and fuel source. The electrosurgical unit (ESU) pencil triggers most operating room fires. Carbon dioxide (CO2) is a gas that prevents ignition and suppresses fire by displacing oxygen. We hypothesize that a device can be created to reduce operating room fires by generating a cone of CO2 around the ESU pencil tip. One such device was created by fabricating a divergent nozzle and connecting it to a CO2 source. This device was then placed over the ESU pencil, allowing the tip to be encased in a cone of CO2 gas. The device was then tested in 21%, 50%, and 100% oxygen environments. The ESU was activated at 50 W cut mode while placing the ESU pencil tip on a laparotomy sponge resting on an aluminum test plate for up to 30 seconds or until the sponge ignited. High-speed videography was used to identify time of ignition. Each test was performed in each oxygen environment 5 times with the device activated (CO2 flow 8 L/min) and with the device deactivated (no CO2 flow-control). In addition, 3-dimensional spatial mapping of CO2 concentrations was performed with a CO2 sampling device. The median ± SD [range] ignition time of the control group in 21% oxygen was 2.9 s ± 0.44 [2.3-3.0], in 50% oxygen 0.58 s ± 0.12 [0.47-0.73], and in 100% oxygen 0.48 s ± 0.50 [0.03-1.27]. Fires were ignited with each control trial (15/15); no fires ignited when the device was used (0/15, P < 0.0001). The CO2 concentration at the end of the ESU pencil tip was 95%, while the average CO2 concentration 1 to 1.4 cm away from the pencil tip on the bottom plane was 64%. In conclusion, an operating room fire prevention device can be created by using a divergent nozzle design through which CO2 passes, creating a cone of fire suppressant. This device as demonstrated in a flammability model effectively reduced the risk of fire. CO2 3-dimensional spatial mapping suggests effective fire reduction at least 1 cm away from the tip of the ESU pencil at 8 L/min CO2 flow. Future testing should determine optimum CO2 flow rates and ideal nozzle shapes. Use of this device may substantially reduce the risk of patient injury due to operating room fires.
手术室火灾是一种对手术患者构成严重威胁的哨兵事件，其发生频率至少与手术部位错误相同。要发生火灾，必须具备火灾三角的 3 个点：氧化剂、点火源和燃料源。电外科设备（ESU）铅笔触发了大多数手术室火灾。二氧化碳（CO2）是一种气体，通过取代氧气来防止点火和抑制火灾。我们假设可以创建一种设备，通过在 ESU 铅笔尖端周围产生 CO2 锥形来减少手术室火灾。通过制造发散喷嘴并将其连接到 CO2 源，就可以创建这样一种设备。然后将该设备放置在 ESU 铅笔上，使笔尖被 CO2 气体包裹在一个锥形中。然后在 21%、50%和 100%的氧气环境中对该设备进行了测试。ESU 在 50 W 切割模式下激活，同时将 ESU 铅笔尖端放在放在铝测试板上的剖腹海绵上，最多 30 秒或直到海绵点燃。高速录像用于确定点火时间。在每种氧气环境中，以 5 次为一组进行测试，一组设备处于激活状态（CO2 流量为 8 L/min），一组设备处于非激活状态（无 CO2 流量控制）。此外，使用 CO2 采样设备对 CO2 浓度进行了三维空间映射。对照组在 21%氧气中的中位±SD[范围]点火时间为 2.9 s±0.44[2.3-3.0]，在 50%氧气中为 0.58 s±0.12[0.47-0.73]，在 100%氧气中为 0.48 s±0.50[0.03-1.27]。每次对照试验都点燃了火灾（15/15）；当使用该设备时，没有点燃火灾（0/15，P<0.0001）。ESU 铅笔尖端末端的 CO2 浓度为 95%，而在底部平面上距铅笔尖端 1 至 1.4 厘米处的平均 CO2 浓度为 64%。总之，可以通过使用发散喷嘴设计来创建手术室火灾预防设备，该设计使 CO2 通过，形成灭火锥形。在可燃性模型中，该设备可有效降低火灾风险。CO2 三维空间映射表明，在 8 L/min 的 CO2 流量下，至少距离 ESU 铅笔尖端 1 厘米处可有效减少火灾。未来的测试应确定最佳 CO2 流速和理想的喷嘴形状。使用该设备可大大降低因手术室火灾而导致患者受伤的风险。
