Anatomy and Timeline of a DCS Hit
Luke Moloney, 29 May 2013
While diving last week near Egmont, BC, I had my first DCS hit. The bogeyman of technical divers finally caught up with me. It was an underserved hit, in that it was unexpected, and not brought on my violating decompression obligations or ceilings. Even DAN doctors apparently found my case a bit strange. I'd like to relate my experience to other divers so they can avoid the discomfort I went through, but also to help develop a protocol that divers should follow while trying to get treatment for DCS, which I didn't do.
I did 2 dives that day, both deco dives. My buddies and I were all diving rebreathers with trimix diluent, trimix bottom bailout and nitrox deco bailout. The first dive, at about 11:03 was to 61m for a total run-time of 89 minutes. The second dive, after a 136 minute surface interval was to 63m max depth for 103 minutes. On the second dive I could have surfaced sooner, but kept to the longer deco schedule of my dive buddies. Also, I was already feeling DCS symptoms before surfacing, so I was keen to do more deco than required.
Between the dives, rather shortly after the first dive I was tidying up the deck of the boat, arranging bottles. In moving a 12l (aluminum 80) bailout bottle I somehow injured my shoulder. I'm not a kinesiologist so I can't adequately explain what I did, but something when pop in my shoulder while moving a bottle. It didn't hurt too bad, but wasn't comfortable and I thought to myself "I'd better be more careful slinging these heavy stages around". I didn't really notice it again until shortly before the second dive when I though it a bit sore, but nothing extreme. Maybe a pain level of 1.5 out of 10.
The DCS Incident
The second dive went without incident, for the most part. I followed my dive computer's deco profile, but on reaching about 6m I started to feel a pain in my shoulder right where it hurt when I injured it. I immediately suspected DCS due to the fact that I'd just ascended from a deco dive. My dive buddies had a bit longer deco obligation than I; I think this is because I followed my ceiling rather closely while they were a bit tardier reaching some of the deep stops. I ended up doing more than 10 minutes of extra deco at the final 6m stop. I ran my rebreather on manual O2 injection so I was breathing a PO2 of 1.0-1.2, rather than the standard 0.7, as a precaution.
On surfacing (16:05) with the boat I took my time getting out of the water and passed my bottles up to the captain, just to keep my exertion low. When back on deck, I paid attention to my shoulder a bit and then announced that I was bent. I went back on the 'breather and breathed a PO2 of 1.0 until we reached shore. Peter, who'd had experience with DCS, advised that I do no lifting, that I take myself back to the cabin and relax with an O2 bottle. I had a nice little 30 of O2 along on the trip for emergencies just such as this. Peter helped me out of my drysuit and kept a keen eye on me to make sure my condition was stable.
The Emergency Response Plan
16:45: pain level 5/10
While I relaxed, Peter went to call 911. We didn't have cell reception in our cabin, but the admin office had a land line. He advised the 911 dispatcher that there was a diver suffering DCS and needed immediate medical attention. Because of where we were, he was advised that it would be faster for me to be driven to St. Mary's hospital (in Sechelt) for examination rather than waiting for an ambulance. I had a good O2 bottle (plus spares in case I ran out) so off we went. Scott ran me to St. Mary's. Peter asked the dispatcher to have emergency in St. Mary's ready to receive me for immediate examination and probable ambulance dispatch to VGH for hyperbaric oxygen therapy (HBOT).
19:00: pain level 5/10
When we got to St. Mary's, however, I was asked the usual questions: Are you married? Who's your family doctor? Any drug allergies? Have you been to this hospital before? I was not asked anything relevant to the incident, AFAIK, such as How long has it been since the DCS incident? Are symptoms getting worse? Have you been breathing pure O2? Have you had a DCS hit before?
I was put in a secondary waiting room for about 20 minutes. As the last ferry departure was approaching (so I thought) I was about to leave when the nurse asked to take my vitals. And then wait. I was about to leave again when the doctor asked to speak with me. It was a short interview as time was off the essence. He advised me that he was unaware I was on my way, that there was no way to get an ambulance to get me to the ferry on time, and that I'd better just go by myself. He volunteered to call VGH hyperbaric unit on my behalf and have them ready to receive me. I told him I would have the steward on the ferry arrange an ambulance for me.
19:50: pain level 6/10
When we got to the ferry, just in time for the last boat, which I'd been repeatedly told was at 20:00, there was no boat there. Scott dropped me off and went back to the cabin. I should probably have kept the O2 bottle, and I probably should have talked him in to staying with me, but I didn't. I just lay down in the waiting room and waited for a boat while the ache in my shoulder got worse.
20:55: pain level 5/10
On the ferry, when the chief steward's office opened (about 10 minutes into sailing) I informed the steward I was having a medical emergency and needed his help. I asked him to call VGH, inform them of a diver suffering from DCS and to dispatch an ambulance to meet me at the terminal. He did as I requested, but what I didn't notice is that he didn't talk to the hyperbaric unit. He talked to admissions or something like that. Despite my insistence, nobody notified the hyperbaric unit that I was coming.
21:30: pain level 7-8/10
At the ferry terminal, the walk to the arrival entrance was quite challenging. It's about 200-300m of elevated walkways. I had 2 small bags with me over my good shoulder and was using one as an arm sling. I understood why it's called "the bends". I was involuntarily bending over from the pain. I was dismayed to see no ambulance so I called 911 myself. After some explanation I was told an ambulance would arrive shortly as it was already on its way. Even standing was hard so I sat on the ground and waited.
21:40: pain level 7/10
In the ambulance I was given oxygen at my request. The paramedic gave me the prongs-in-nostrils O2, not a mask. I should have insisted on a mask. I reminded her that we had to go to VGH, not the closest hospital, as VGH has the only hyperbaric unit around. It took some insistence to change their plan to take me to LGH. As she asked me the basics and took my vitals, I asked her to call VGH and make sure the hyperbaric unit was aware of my arrival and confirm they would be ready. She used her mobile to call VGH and tell them of a DCS-suffering diver arriving, but somehow the DCS information, again, got ignored, and I was just sent into general admitting.
22:00: pain level 7/10
At VGH I was slowly admitted through a variety of admin staff. While being asked by various people my age, my marital status, my drug allergies, my family doctor and a variety of other questions completely unrelated to my emergency, I mentioned again and again that I was suffering from DCS and needed immediate hyperbaric therapy. I was then told to sit in a corner, next to a large O2 bottle with no regulator on it, while they ignored me for a few hours. During that time a nurse came and took me away for blood extraction (I wasn't told why and probably should have consented only if they were looking for bubbles in my blood). Luckily I'd brought warm water from the ferry and kept hydrating. Another technician took me away for an ECG. Patients are kept rather in the dark about what's going on here and I was getting delirious from the pain.
23:00: pain level 8/10
As an indication of how far my expectations were from how the actual emergency was being handled, I had a funny conversation. As she was fitting me with ECG probes, I had a discussion with the technician (paraphrased):
Me: What are these probes for?
Tech: We're doing an ECG on you.
Me: Ah, so you're checking me for a PFO or bubbles?
Tech: What's a PFO?
Me: You know, a patent foramen ovale?
Tech: What's that?
Me: You know, a "hole in the heart". An opening between the left and right atria that allows bubbles in the veinous blood to flow to the arterial blood. It makes DCS incidents much more dangerous for people who have a PFO.
Tech: Oh, I'd not heard it called that in a long time. We're just doing an basic electrical scan of your heart.
Me: Oh, you're not a hyperbaric doctor?
Tech: No, I'm just an ECG tech. We're done here. You can put your shirt on and go sit in the corner again.
I was very distressed and frustrated. I was thinking I should have just done in-water recompression, but it was way too late for in-water recompression. Also, that could be dangerous, and my dive gear (and dive buddies) were all in Egmont.
0:00: pain level very high
Finally I was taken to an actual examination room and asked to put on a gown and lie down on a bed. This is when the nurse fitted me for an IV and chatted with me about Egmont, where she's soon to be married. After she took my vitals I asked her why I was not given oxygen. She asked if I wanted oxygen, to which I replied I should be on oxygen. She looked at the heart monitor and told me I didn't need oxygen as my perfusion was near 100% - normal. I rather snapped at her that I didn't want oxygen, but rather that oxygen and hydration are indicated for anyone suspected of DCS. She gave me the prongs-in-the-nostrils style again, instead of the mask-over-the-face kind. She also asked me if I wanted "something for the pain" to which I replied that I wanted "something for the cause of the pain, and that's recompression therapy". I know that you're not supposed to take painkillers if you have DCS, as you need to monitor the pain to know if the HBOT is working.
0:05: pain level 9/10
A doctor finally came to see me! Looking at my chart and asking a few casual questions about my dives, he informed me that he didn't think I had DCS, but just a sore shoulder. I insisted that there's at least a 90% chance that I'm suffering DCS and that I needed immediate HBOT. With a sigh, he said he'd page the on-call hyperbaric doctor for me and get a second opinion.
I was aghast and very upset. Here's the emergency doctor who clearly doesn't understand diving medicine telling me I don't have DCS and only calling the hyperbaric doctor at my insistence. Not only that, the 911 dispatch didn't notify VGH hyperbaric medicine unit (either time they were called), the doctor in Sechelt (who said he would call on my behalf) didn't notify them, the steward on the ferry and the paramedic (both to whom I'd insisted they specifically call the hyperbaric medicine unit) failed to get a message through, admissions at VGH failed to notify them, the various nurses and techs who'd examined me didn't pass on a message. At so many points did the actual DCS complaint get completely ignored and converted to a "sore shoulder" complaint. I was staggered, and still am.
0:20: pain level 9/10
After the hyperbaric doctor finally called back to emerg, I could overhear the emerg doctor's side of the story. He occasionally came to ask me clarifications such as: Where were you diving? How deep was the second dive? What was your time between dives? After a few of these interruptions he came and asked me to talk to hyperbaric doctor myself. I staggered bare-backed out into the lobby (I couldn't tie the gown in the back very well because my shoulder mobility was quite limited) and half climbed up on the some stretchers that were in the way to get to the phone. Dr. Kerrie asked me to explain the situation because he was "having a hard time getting a clear picture from the emergency doctor". After a quick run-down he informed me that it sounded like an odd case, but he would be in as soon as he could and I would "probably be going for a dive [in the chamber] tonight". Again the gravity of it sunk in. This is the first time anybody in the hyperbaric unit heard of my DCS incident. He wasn't even at the hospital. I was interrupting his sleep and it would certainly be a while before I was in the chamber. After going back to my bed in the examination room, the nurse hurried in and swapped my oxygen nostril thing out for a proper mask. "They finally got the message" I thought. Soon I would be in competent hands.
~1:00: pain level 9+/10
When the doctor came in to examine me he did a neurological examination: I squeezed his fingers, pulled his hands, demonstrated balance, walked forward and backward, followed his finger with my eyes. After a few more questions he asked me to lie down and relax while the rest of the on-call HBOT techs arrived.
I was taken to the hyperbaric unit. The doctor put me in a wheelchair, with a portable oxygen bottle and my belongings. This contrasted well with the previous treatment of no oxygen and carrying my own things around that I'd had the first few hours.
In the hyperbaric unit I changed into fireproof scrubs, was fitted with a neck-seal and given the drill of how the dive will go. I was also asked if I would participate in a multi-centre study that is gathering blood samples from DCS patients that hopes to find bio-markers for DCS susceptibility. I consented and nurse attendant Scott took a blood sample. I "signed" the consent form, which was more of a rough squiggle from my now-very-weak arm which could barely hold a pen.
2:30: pain level 9+/10
Dive time! After settling into the DCS chamber I was ready to dive. Zora was my attendant and gave me last-minute instructions and assistance. I was told that, if it really is DCS, the pain should go away almost immediately, but that we'd be in the chamber for about 5 hours. I was on a "schedule 6" HBOT dive plan which goes to 20msw (3ATA) for about 2 hours and then slowly ascends with a long stay at 10msw (2ATA). I was to do 20 minute oxygen periods (PO2 of 3.0!) with 5 minute air breaks between. My descent rate was fast! It seemed about 2 minutes to get to 20m. The air in the chamber got hot very fast and Zora seemed to be having a good time. I later learned that the elective dives descend very slowly so this more rapid descent is probably fun for the attendants. About 5 seconds into the dive I felt an astounding sensation in my shoulder. It felt like ball-bearings or glass marbles were rolling around in my shoulder joint. It hurt like heck, but any break from the "normal" pain was very welcome. I also felt exonerated: after having the DCS complaint downplayed or ignored by everyone, I was right. I did have DCS, and this would help.
4:30: pain level as low as 4
A chamber ride is not super comfortable. You wear an oxygen hood: sort of a stiff plastic bag over your head into which oxygen is piped. There's an oxygen exhaust pipe as well. With your breathing, this hood expands and contracts a bit so your head keeps bobbing around. I was exhausted and wanted to sleep but that was out of the question. I'd brought a book (from the ferry gift shop) but was mostly too uncomfortable to read. The first hour of the dive was painful. After about 90 minutes my pain level was fluctuating between 5 and 9+. This was puzzling to both myself and the doctor. Dr. Kerrie suspected I was having muscle spasms at the site where the bubbles were and had me take aspirin to reduce inflammation. At around 120 minutes into the dive I almost nodded off. In the uncomfortable environment of the chamber I found that strange and noted that, finally, my shoulder pain was almost gone. I now had residual pains around my elbow, wrist and a bit still in my shoulder, but that's progress!
6:00: pain level low
At about this time I started to notice that I was suffering Pulmonary Oxygen Toxicity (POT). I'd breathed a lot of oxygen in the previous 24 hours. I could no longer take a full breath of oxygen, and anything but shallow breathing brought on coughing. In the oxygen hood, coughing is very unpleasant and the oxygen even started to smell bad to me. Zora shortened one of the oxygen periods for my benefit.
7:15: pain level minimal
Upon surfacing I was hella groggy, but cured. The POT was really bad by the time the doctor joined us in the chamber (there's an air lock) at 10msw. He fitted Zora with an oxygen hood so she could do her deco while he asked me a few questions. He also cut out my last oxygen period after asking me to take a deep breath (which I couldn't in my hood). After we finished our ascent, I was asked for more blood (the study involves pre- and post-dive blood samples), given a bit of breakfast and sent on my way. Dr Kerrie gave me the number to his department and said he'd call me later after his regular day shift. I slept well after a lengthy stagger/bus ride home and a shower.
I slept much of the day but finally Dr. Kerrie called to make sure I was doing well. The prescribed Ibprufen helped with inflammation and pain so I was feeling pretty good. My shoulder did (and still does) feel bruised. He had a hard time giving me a specific stay-out-of-the-water time, but suggested something between 2 and 4 weeks. I also suggested I'd wait for my shoulder to mend and then set my computer to a higher conservatism factor. I've since noted that my computer (Liquivision X-1, V-Planner live) is set to the highest conservatism factor already!
Suggested DCS Protocol for Divers
While resting up and post-morteming with my dive colleagues I'm shocked at how poor the emergency response was to this incident. Nobody seemed to understand, or take seriously, DCS. I was ambulatory, able to answer questions and not bleeding profusely so I was regarded as a "sore shoulder", rather than a time-sensitive life-threatening medical emergency case.
I will talk to the hyperbaric unit at VGH for their recommendation and try to figure out why I was so darn ignored. I don't have a lot of confidence I can affect a positive change in the lassitude of medical administration, but I think we can change how divers react to this type of incident.
Talking it over with my colleagues, we've come up with the following protocol, for a diver suffering, or suspected of suffering, DCS:
* As the patient, you should relax, hydrate and breathe oxygen. Let your buddies handle your gear and/or leave it on the boat/beach/car or wherever your gear is. Ideally, assign another diver to take care of the gear so you don't have to stress about it.
* Assign an advocate/attendant to take care of you throughout the ordeal. This advocate should be a diver who understands DCS, and is prepared to advocate for you, and help you through the administrative red tape that would otherwise delay or deny you proper treatment. Ideally this attendant/advocate knows something about basic medicine and first aid.
* Call 911 to arrange transportation, whatever seems best. Ambulance if you can get it, or a dive buddy to get you to the nearest hospital for examination. Note, however, that you need to get to a chamber and any interim hospital stops may only delay treatment. There's not much they can do to help you, except give you oxygen and maybe arrange an ambulance.
* Stay on the phone with the 911 operator and ask them to put you through to the VGH hyperbaric unit. Be specific. It has to be a hyperbaric doctor, not a regular doctor. It has to be hyperbaric doctor, not an emergency admissions person. Be patient, but explain that you are representing someone who has a time-sensitive, life-threatening medical emergency for which the only treatment is Hyperbaric Oxygen Therapy (HBOT).
* If that doesn't work, feel free to call the VGH hyperbaric unit directly. I called them to make sure they're OK with this, and Dr. Khezei says they're OK with divers calling directly. Their number is 604.875.4033. Note that if it's not normal business hours you will just get an answering machine and you will need to call the VGH switchboard (604.875.4111) and ask them to page the hyperbaric specialist.
* When it comes time to move the patient (in ambulance or private car) bring an oxygen bottle with a regulator. The attendant will carry the bottle, as well as all of the patient's belongings (if any). Bring an extra bottle, if you can, in case of distress of the patient and/or delays. (S)he will ride in any ambulance, boats or private cars with the patient and keep an eye on the patient. The attendant/advocate will observe the patient and note (in writing, ideally) any changes in condition: awareness, mobility, breathing, pain levels. Ideally this person should not drive so as to take care of patient. (S)he will also take care of any phone calls (such as receiving calls from a hyperbaric doctor) and do all the talking. The patient just breathes pure oxygen (if you have it, the richest Nitrox you have otherwise) for 20 minutes periods, with 5 minute air breaks.
* Upon arrival at the hospital, the attendant stays with the patient and carries any oxygen bottles. Bring your own oxygen, as it may be some time before the hospital admits you or gives you oxygen.
* At this time the attendant will insist on seeing the hyperbaric specialist. Marital status is irrelevant, blood tests are not required, an ECG may be a waste of time, sitting in the waiting room is a life-threatening waste of time. Remind everyone you meet what the situation is. Remind them that you already know the diagosis: Acute DCS, a time-sensitive and life-threatening medical emergency. Also remind everyone that you know the treatment: immediate HBOT. Deny pain-killers (which will interfere with the therapy) insist on immobilization, an oxygen face mask and hydration. If left to wait for more than 5 minutes, demand to know where the hyperbaric doctor is and why you have not heard from him/her. Any movement of the patient is to be by wheelchair. You will probably be detested by the hospital admittance staff, paramedics, nurses and emerg doctors. You will probably be asked to wait outside, to be quiet and ignored. Don't take it. Be patient, keep your cool and remind everyone that the patient is under your medical supervision and you will not leave until you are satisfied that proper, competent medical care is being administered. Remind anyone asking you to leave that you know the diagnosis and the therapy. Remember that they probably don't know, and probably don't believe that you know.
* When the hyperbaric doctor finally arrives, the attendant will do most of the talking. After under the care of a hyperbaric doctor the attendant can leave. There will be 5-10 hours of waiting so you may as well go get some rest, collect dive gear or whatever.
* The attendant should keep his/her mobile phone on to handle getting called by the hospital and offer to pick up the patient (who may be weak and groggy) after therapy.