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n April 28-29 2014 in San Diego, CA, Richard Sadler, M.D., FACS, CDR Joseph Dituri USN (ret), M.S. Simon Mitchell, MB
ChB, PhD, FANZCA, Craig Jenni, JD, Richard Moon, MD, CM, MSc, FRCP(C), FACP, FCCP; and Richard Pyle, PhD met to discuss the topic of In Water Recompression (IWR) with the intent of polling industry leading physicians and divers in the use and practice of IWR. The following is a consensus statement and list of guidelines that came from the invited speakers and input of dive industry professionals. A consensus statement is a
recommendation(s) or general guidelines developed using available evidence and expert opinion in areas where high quality clinical data is limited or does not exist for controversial clinical dilemmas. These guidelines are systematically developed recommendations that assist the practitioner and diver in making decisions. These recommendations may be adopted, modified, or rejected according to needs and constraints and are not intended to replace local institutional policies. They are NOT to be considered a standard or “best practice” for emergency response of decompression illness (DCI). Their use cannot guarantee any specific outcome. These guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They represent basic recommendations that are supported by a synthesis and analysis of the current literature, expert opinion, and open forum commentary combined with any existing data. These statements represent the
opinion, beliefs and best judgments of the aforementioned subject matter experts. As such, they are not necessarily subjected to the same level of formal scientific review as standards. Each person, institution or practice should decide individually whether to implement the principles in this statement based on a careful evaluation of risk vs. benefit, and on the sound judgment of the participants involved situation at that time.
Statements: The definitive emergency response of DCI continues to be a combination of pressure and oxygen in high concentrations.
Oxygen and pressure are preferred over surface oxygen alone in the emergency response of DCI. It is determined that IWR is a viable methodology for first aid (an intermediate step) prior to definitive emergency response of DCI. Immediacy of emergency response with oxygen and pressure may be fundamental to effect optimal outcomes in selected symptomatic divers. The intrinsic advantage of immediacy in IWR surpasses the potential risks for appropriately selected symptomatic divers. IWR has potential for improving outcomes in those divers with symptoms that have rapid onset and a poor prognosis. IWR is rarely a complete and sole emergency response for DCI. All symptomatic divers of DCI shall, if they opt for IWR, be evaluated by a physician knowledgeable in diving and hyperbaric medicine as soon as possible following IWR.
Recommendations for Implementation of IWR: During IWR the diver must be accompanied by a tender. The effectiveness of IWR will be lessened if the diver becomes cold. Maintenance of optimal thermal comfort is therefore important. Indications: While acknowledging the potential benefits of IWR, the potential risks of IWR limits its applications to those divers with symptoms associated with poor outcomes. (Appendix I Tier System) and severe pain. Emergency response time should extend 60 minutes after the resolution of symptoms the total emergency response time must NOT to exceed 120 minutes at depth. The emergency response protocol should be terminated at any time if deemed necessary by either the tender or diver-symptomatic diver. The breathing mixture should be as close as possible to 100% oxygen (with the goal of achieving a PPO2 of 1.6 ATM/BAR); mixtures containing less than a minimum FiO2 of 0.80 (80% inspired oxygen concentration) should not be used for IWR. Emergency response depth should not exceed 20 ft (6m), even if the breathing mixture contains less than 100% oxygen. Periods of breathing air (“air breaks”) are not required due to
additional complexity. The planned ascent rate should be 1ft (0.3m) / min. if possible. In the event of an emergency (such as loss of consciousness in the treated diver) a rapid ascent should be made to the surface. If the diver is convulsing and the mouthpiece is retained, (eg. during use of a retaining strap or if a full face mask is used) ascent should be delayed until the seizure has stopped. If the mouthpiece is not retained an ascent should be made immediately, even if the convulsion continues. If symptoms return during ascent from the planned IWR, the diver may return back to 20ft (6m) if the total time at 20ft (6m) has not yet exceeded 120 min. After exiting the water following IWR, the symptomatic diver must not re-enter the water even if symptoms recur. Mild activity (e.g., gentle finning movement) is acceptable and encouraged during IWR. For severe DCI (e.g. paralysis), judgment will be required to weigh the benefits of quicker IWR with short delay to evacuation vs. immediate evacuation to a hyperbaric facility that may be many hours away. Consultation with an offsite diving medical expert is recommended.
Practical and Logistical Considerations for Equipment: Pre-emergency response informed consent of all potential IWR participants should ideally be obtained. In order to facilitate this, a webinar or video on line should be used where IWR is explained and a standard waiver is signed. Trained IWR divers should practice IWR regularly in order to maintain proficiency. A regulator retention (gag) strap
is strongly recommended to hold the regulator in place in the unlikely event of an oxygen seizure. (See Appendix II Airway Protection) The use of a full face mask is
recommended for trained users. Significant caution is advised for the untrained user. (Appendix II Airway Protection) While rebreathers are recognized
From ‘Beneath the Sea’ to DIVER, what
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as a potential tool for administration of oxygen during IWR, their use in IWR by divers untrained in their use should only be attempted under expert supervision. The symptomatic diver’s depth should be controlled by the use of a
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Photo: Leanna Rathkelly
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