Page 24 - JSOM Summer 2022

74
Immersion blast injuries were commonly seen in World War II, associated with clinical improvement. Other authors have
when sailors, forced to abandon their ships, were in the water reported neurologic improvement in CAGE patients despite
as a torpedo, depth charge, or bomb then exploded close to delays to initial HBO treatments of as long as 39, 52, and 60
2
41
their location. In one episode, 125 British sailors went into hours after the embolic event. 72,75,76 Residual neurologic defi-
the water wearing life preservers after their ship was sunk, but cits are often seen after the first treatment, especially when
35 were subsequently killed by a nearby depth charge explo- HBO therapy is delayed; repeated HBO treatments are indi-
2
2
sion. In another event from 1967, the Israeli destroyer Eilat cated in such patients.
was sunk by an Egyptian missile. Twenty-seven of the 35 sur- The Officer in Charge and the Medical Regulating Control Of-
vivors had blast lung and five required ventilatory support. ficer on board the LHA would coordinate with the 5th Fleet
Twenty-two of the survivors had bowel perforations. In a Surgeon’s office to determine the hyperbaric treatment facility
41
third incident, an underwater charge detonated near 13 indi- to which the CAGE casualty should be transported. Identifying
viduals who were swimming for recreation. All 13 got out of these facilities is part of the routine operational planning con-
the water alive, but two suffered cardiac arrest within a min- ducted by deploying forces, with the caveat that chamber avail-
ute of their exit from the water. Within 10 minutes, two addi- ability may vary as a result of ongoing hyperbaric treatments,
tional swimmers suffered a cardiac arrest, and by 30 minutes chamber maintenance, or other contingencies. Considerations
after their exit from the water, another two had died. These in chamber selection would also include what additional medi-
fatalities were likely caused by pulmonary barotrauma with cal or surgical resources the casualty might require.
resulting gas emboli to cerebral or coronary arteries. 41
Naval Support Activity Bahrain is home to the naval forces
A preventive measure recommended by British surgeon Sir
Zachary Cope during World War II is worthy of mention. He assigned to the US Central Command as well as to the head-
noted that injuries from underwater blasts might be mitigated quarters of the United States 5th Fleet. There is a hyperbaric
by the simple act of having the casualties immersed in the wa- chamber with a US Navy Undersea Medical Officer at that
ter float on their backs. This maneuver avoids exposure of the location.
chest and abdomen to the full effect of the underwater blast An important resource in arranging treatment for casualties
wave. 41 who need emergent HBO is the Divers Alert Network (DAN).
2
This organization maintains a 24/7 emergency hotline (1-919-
Hyperbaric Oxygen Treatment for 684-9111) for diving emergencies and has a list of hyperbaric
Cerebral Arterial Gas Embolism chambers that are currently available to provide emergent
Casualty 6, the individual with pulmonary barotrauma from HBO treatment. In this scenario, additional DAN-identified
2
an immersed blast exposure has suffered a CAGE secondary chambers in the area include:
to his lung damage. This life-threatening injury occurs when – Wudam Al Sahil Naval Base in Oman
damaged alveoli or bronchioles allow air bubbles to enter the – The Royal Hospital in Oman
pulmonary venous system and then subsequently return to – Dubai Police Department Chamber
the left side of the heart, from which they are subsequently – Subtech Diving Middle East Commercial Complex in
pumped into the systemic arterial sys tem. Both the cerebral Dubai (personal communication, Dr. Jim Chimiak, DAN
and the coronary circulations may be affected, with secondary Chief Medical Officer, 16 July 2021).
stroke-like symptoms, hemiplegia, a decreased state of con-
sciousness, cardiac dysrhythmias, or cardiac arrest. Once a proposed hyperbaric treatment facility is identified, the
chamber personnel at the intended treatment chamber should
Definitive treatment for CAGE is hyperbaric oxygen deliv- be contacted prior to initiating transport, to confirm availabil-
ered in accordance with the treatment guidelines found in the ity and readiness to treat.
40
US Navy Diving Manual. The most important prehospital
measure in caring for casualties with CAGE is to administer Plasma Resuscitation for Burn Casualties
100% oxygen or as high an inspired oxygen fraction as can be Casualties 2 and 5 both require fluid resuscitation for severe
achieved with the available respiratory support technology. burns. Burn patients are hypovolemic as a result of fluid loss
71
The patient should be maintained in a horizontal, not a head- from the vascular space to the interstitial space and require
77
down position. LR may be used to prevent dehydration during volume replacement. The standard of care for fluid resus-
transport to a hyperbaric treatment facility, but excess admin- citation in burn patients at present is crystalloids and the
istration of crystalloid fluids may worsen the cerebral edema destroyer carries Lactated Ringer’s solution suitable for this
that can result from CAGE. 71 purpose. Plasma was formerly used for burn resuscitation,
but clinicians moved away from this treatment option because
Hyperbaric oxygen should be provided even if the signs and
symptoms of CAGE resolve spontaneously or with 100% ox- of the infection risk that plasma transfusions entailed during
ygen, since the manifestations of CAGE may recur without WWII when plasma was pooled and not tested for hepatitis.
HBO2 treatment. Whenever possible, the patient should Now that that risk has been virtually eliminated, there have
71
be transported at altitudes under 1,000 feet or in aircraft in been recent calls from leading burn surgeons to reconsider
77
which the cabin can be pressurized to 1 atmosphere. 71 plasma resuscitation for burn patients. As far back as 2010,
a survey of centers associated with the International Society
With respect to the time urgency for HBO treatment, Coving- for Burn Injuries and the American Burn Association found
2
ton observed: “There is little argument that a shorter time to that in 13.9% of the respondents, plasma was the preferred
hyperbaric oxygen therapy treatment is likely to yield a more fluid for burn resuscitation. 78
favorable patient outcome.” Extended delays to hyperbaric If plasma is found to be superior to crystalloids for burn resus-
72
oxygen treatment are associated with less favorable outcomes citation, it might be especially advantageous for treating burn
in CAGE patients, 71,73 but one study found that HBO treat- casualties in the prehospital shipboard environment, since
2
ment administered within 8 hours of symptom onset was still
22 | JSOM Volume 22, Edition 2 / Summer 2022