Dive_Man_ChangeA

CHAPTER 21 — Recompression Therapy Change A 21-23 21-5.6.2.1 Additional Personnel. If the patient has symptoms of serious decompression sick- ness or arterial gas embolism, the team will require additional personnel. If the treatment is prolonged, a second team may have to relieve the first team. Patients with serious decompression sickness and gas embolism would initially be accom- panied inside the chamber by a Diving Medical Technician or Diving Medical Officer, if possible. However, treatment should not be delayed to comply with this recommendation. 21-5.6.2.2 Required Consultation by a Diving Medical Officer. A Diving Medical Officer shall be consulted, if at all possible, before committing the patient to a Treatment Table 4, 7, or 8. The Diving Medical Officer may be on scene or in communica- tion with the Diving Supervisor. 21-5.6.3 Oxygen Control. All treatment schedules listed in this chapter are usually performed with a chamber atmosphere of air. To accomplish safe decompression, the oxygen percentage should not be allowed to fall below 19 percent. Oxygen may be added to the chamber by ventilating with air or by bleeding in oxygen from an oxygen breathing system. If a portable oxygen analyzer is available, it can be used to determine the adequacy of ventilation and/or addition of oxygen. If no oxygen analyzer is available, ventilation of the chamber in accordance with para- graph 21-5.6.6 will ensure adequate oxygenation. Chamber oxygen percentages as high as 25 percent are permitted. If the chamber is equipped with a life-support system so that ventilation is not required and an oxygen analyzer is available, the oxygen level should be maintained between 19 percent and 25 percent. If chamber oxygen goes above 25 percent, ventilation with air should be used to bring the oxygen percentage down. 21-5.6.4 Carbon Dioxide Control. Ventilation of the chamber in accordance with para- graph 21-5.6.6 will ensure that carbon dioxide produced metabolically does not cause the chamber carbon dioxide level to exceed 1.5 percent SEV (11.4 mmHg). 21-5.6.4.1 Carbon Dioxide Monitoring. Chamber carbon dioxide should be monitored with electronic chamber carbon dioxide monitors. Monitors generally read CO₂ percentage once chamber air has been exhausted to the surface. The CO₂ percent reading at the surface 1 ata must be corrected for depth. To keep chamber CO₂ below 1.5 percent SEV (11.4 mmHg), the surface CO₂ monitor values should remain below 0.78 percent with chamber depth at 30 feet, 0.53 percent with chamber depth at 60 feet, and 0.25 percent with the chamber at 165 feet. If the CO₂ analyzer is within the chamber, no correction to the CO₂ readings is necessary. 21-5.6.4.2 Carbon Dioxide Scrubbing. If the chamber is equipped with a carbon dioxide scrubber, the absorbent should be changed when the partial pressure of carbon dioxide in the chamber reaches 1.5 percent SEV (11.4 mmHg). If absorbent cannot be changed, supplemental chamber ventilation will be required to maintain chamber CO₂ at acceptable levels. With multiple or working chamber occupants, supplemental ventilation may be necessary to maintain chamber CO₂ at acceptable levels.