Fully aware of the physical dangers and logistic hurdles to be overcome Verna nonetheless decided to put together another team and return to Boesmansgat in 2004. Naturally this would mean a year of progressively deeper dives and a lot of organising and planning before we could set a final date for the trip. Little did we know that 2004 was to have a very scary start for all of us and for me in particular.
DCI- what now?
As careful as I’ve always been over the years, as I said at the beginning of this tale no decompression model is foolproof. On Saturday the 3rd of January 2004 I may have had first-hand experience of the unknown error factor in the tables we use. I was at Badgat for the weekend to support Verna van Schaik on a dive that she planned to reach 160 metres down the incline shaft. We’d been at Badgat a few weeks earlier when Verna and I had done 108 metres down the shaft and along the tunnel at the bottom to retrieve a stage bottle for Don Shirley. I remember thinking what a great dive it had been and how everything had gone according to plan. I’d even been fairly warm most of the dive in spite of doing the dive of 133 minutes in my wetsuit. On Friday the 2nd of January I did a build up down the highway through the blast-door and down to around 60 metres. Also if memory serves me, the team placed some stages in the shaft at thirty six metres and even down as far as 80 metres. Excluding the Trimix dives these dives required an average of fifteen to twenty minutes of decompression. All of them went without any incident or indication of what was to come.
The dive
For the 160 metres dive I planned to use a profile I’d dived many times before with a helium mix of 8/60 (8% oxygen, 60% helium) this gives an equivalent depth of about forty metres which meant I would be very clear headed and able to assist Verna in transferring stage cylinders as she ascended the shaft.
I entered the water on schedule and swam to the blast-door via the highway, a tunnel approximately one and a half metres high by four-six metres wide that connects the main shaft to the open pit. It is approximately 110 metres long and sixteen-eighteen metres deep, depending on the water level. I followed our pre-laid jump-line from the entrance and soon found the permanent line that showed the way to the blast-door. This half metre by half metre door is set in a brick wall and was literally used to shield the effects of explosives set off during the active mining days. As I swam along the dark highway I swept my primary torch from side to side slowly, passed the first intersection that joins the two entrances to level one, the second intersection which joins the left and right hand sides of level one, and the other two possible routes I could take on this level, all the while running my dive through my mind and reviewing when I’d meet Verna and what I needed to do. I was confident everything was going according to plan.
Arriving at the blast-door I squeezed my single stage, my twin fifteen litre back mounts and myself through the door. Once through the door I checked myself to see everything was okay, and started down the shaft. As I moved down past the second level at twenty three metres, and the fourth level at about 70 metres I checked on Verna’s stages to make sure the valves worked and were not stuck closed.
Rendezvous at 107 metres
I got to 107 metres a little earlier than anticipated, and although Verna did not appear from the incline in the next long two to three minutes I was not too concerned. Although after about a minute more I began to do the mental calculations for how long I could wait at this depth and have enough gas to be safe. I knew in the back of my mind that I had enough HeliAir to stay for about twelve minutes. As a precaution I ascended to about 90 metres and waited.
An element of this type of support diving that is of vital importance and almost impossible to prepare for fully, is the way one’s mind can begin to work against one. In fact the more knowledge you have the worse it can be. I knew exactly how long Verna could survive on the gas she had, I knew I had very few options if she was late or did not reappear in the tunnel very soon. I could swim down the tunnel and wait at the entrance to the inclined shaft for a minute or so, or I could go a short way into the incline shaft in an attempt to find Verna. This would have been a very risky proposition as it would almost certainly extend my bottom time beyond my planned stay. I’d then have to rely on the safety built into my decompression schedule, my experience, my faith and a lot of luck to get out of the cave safely.
Finally, and the hardest decision I could imagine having to make as a support diver, I could decide to begin my ascent, perhaps very slowly to give Verna longer to come out of the tunnel, but this option would mean that I was conceding that my friend had died and would not be coming back; something I knew I never wanted to do. I knew that Verna would be fully aware of the factors governing her chances of survival should something go wrong. I knew we had an almost unspoken agreement not to endanger our own lives to try and save another. No one wants two deaths in a hopeless rescue attempt. But I also know that we’d both try everything in our power to help the other if we thought there was even the smallest chance of success.
One minute stretched by, nothing but my own light and the sound of my own breathing. I spent another long minute occupying my mind by slowly sweeping my torch around the narrow confines of the bottom of the shaft and the even smaller 90 metres square rock cavern I found myself in. Not surprisingly the scenery didn’t hold my attention very long. The minute strolled by, still nothing. Finally, a faint glow appeared below me. As I descended again to the bottom the glow gradually grew into Verna as she emerged from the tunnel leading off the shaft at 107 metres. It’s hard to describe the sense of relief that flooded through me. I remember speaking out loud into my regulator “I knew she’d be okay!”. Very relieved to meet Verna, I checked she was okay and picked up two stages from her. At this point, at 110 metres, I struggled for a moment to attach one stage to my harness so I elected to simply hold on to it on the way up. This should also have caused no real problem since the stage was aluminium and nearly empty, therefore almost neutrally buoyant. But the effort of struggling to attach the cylinder was a factor I had not accounted for in my plan.
The doctors tell us that any exertion at depths like this can be a cause of problems, but at that point I felt no pain or discomfort other than the effort of holding the tank. My first decompression stop at 73 metres more or less coincided with Verna’s first stop as well. After that I pretty soon moved up on my own dive and left her in the care of the next support diver. I did not stay at 107 metres for more than about six minutes total. The dive itself went fine, although I was a little stressed when Verna was late for our meet up. All in all I picked up three additional stage cylinders which meant I had five on me as I swam back to the blast-door. To get through I had to methodically unclip each of the stages in turn, pass them through the door and clip them to the main line on the other side of the blast-door. Then I swam through and reattached each one to my harness. Once that was done I could finally start out along the highway to my oxygen cylinder that hung on a line at six metres just outside the entrance to the cave. At that point I experienced no discomfort or pain of any kind. I completed all my decompression stops up to six metres and changed to oxygen at the correct depth and time. My profile for this dive is shown on page 100. As with all the profiles shown in this book, it is provided for information only and not intended for use by anyone other than the author.
Compare this table with the one in chapter 5, which, although designed for a 110m dive, is built up very differently. The major difference between the two is the inclusion of so called “Deep Stops”. The technique of starting our decompression with short deeper stops. Back in 1993 we figured the faster you get shallow, the better. Time and the experience of divers from around the world have taught us differently. Most modern decompression theories build in some sort of “deep stop” in an attempt to minimise so-called micro bubbles in the tissues of the diver. Still I guess the term “deep stops” is accredited to Richard Pyle, an ichthyologist from Hawaii. Dr Pyle found that when he stopped on his way to his first scheduled decompression s
top (to puncture deep water fishes’ swim bladders) he felt much better after the dives. Richard Pyle duly documented his findings and the rest, as they say is history (Pyle, DeepTech 5:64).
Neurological bend?
Once I’d finished all my scheduled decompression stops I spent a few extra minutes on oxygen at six metres, as is my practice before finally surfacing after 114 minutes. I still had no pain or any other symptoms of DCI. After getting out of my heavy tanks and filling my BC to float my gear on the surface, I rested for a few minutes. In retrospect I might have waited a bit longer, although I can never know if it would have made any difference. I proceeded to climb up the ladder that leads out of the water and make my way up the twenty-odd metres of rough stairway and loose gravel to the top of the hole where I started to get out of my wetsuit. So much for no heavy exertion after a deep dive, but by then, although I didn't know it, I was probably already not thinking clearly. Within about twenty five minutes of surfacing, I began to see visual disturbances or ‘auras’ as they are called in a migraine headache. I should point out that I do have a history of migraines and sometimes quite bad ones. The problem is that the symptoms I was experiencing at that point were no different to those I’d had with migraines in the past. These symptoms are very similar to those experienced by divers who have neurological decompression sickness! Incordination, lethargy, fatigue, numbness, pain and headaches to mention a few. If it was indeed DCI it meant that a bubble/s of nitrogen or helium had formed during my ascent and lodged somewhere in my central nervous system or CNS. The bubble, or more likely bubbles could be anywhere from the spine upwards to the brain. If not very promptly treated this could mean temporary or permanent loss of memory, trouble walking and talking, hearing problems and other similar effects.
At its worst this type of decompression sickness can mean permanent paralysis or even death from a bubble in the brain. So what did I do? I took two muscle relaxants called Norflex, and promptly went to sleep. I woke up hours later, retching and unable to remember my name. More to the point, I was unable to articulate anything intelligible enough to convince my wife and friends that I was ‘only’ having a migraine. My wife and friends were by now becoming very concerned about me and, on the advice of DAN evacuated me to the hospital in nearby town of Barberton. From here I was taken by ambulance 450 kilometres to Pretoria, only to find the chamber closed. I was then flown courtesy of DAN to a mono-place chamber in Welkom, a relatively remote town , almost totally dependent on the mining industry for its existence. I arrived in Welkom on Sunday the 4th of January at 7:05 am. I was placed in the very able care of Dr Frik Ziervogel and Sister Hiske Smart. The doctor took one look at me and decided to take a conservative approach and treat me as if I had a neurological decompression illness. So I was placed in the chamber on US Navy Treatment Table 6. This table involves an almost five hour stay in a decompression chamber (more correctly termed a recompression chamber).
Depth
Runtime
Gas
16
10
EAN32
36
12
HeliAir 8/60
110
21
HeliAir 8/60
73
26
HeliAir 8/60
60
29
HeliAir 8/60
50
31
HeliAir 8/60
40
33
EAN32
32
34
EAN32
28
36
EAN32
26
37
EAN32
24
38
EAN32
22
40
EAN32
20
43
EAN50
18
45
EAN50
16
53
EAN50
12
56
EAN50
10
63
EAN50
8
72
EAN50
6
80
Oxygen
4
92
Oxygen
2
114
Oxygen
The author decompressing in Boesmansgat (courtesy Theo van Eeden)
Resolution
I responded to the treatment well and by the end of it could correctly fill in a form with my name, identity number, address etc. I should stress again that although I responded to the treatment table, I was at eighteen metres on oxygen for almost two hours and then at nine metres for a further two hours. This degree of oxygen might have had a neutralising effect on the Norflex. Besides, it was almost thirty six hours after I took the Norflex, so it had probably worn off anyway. Yet again, I’ll never know. Even so, the doctors who saw me later were also not prepared to say it was just a migraine. They felt that my symptoms had presented too soon after the dive to make a definitive statement that what I had experienced was a migraine.
US Navy Treatment Table 6:
Oxygen Treatment of Type II Decompression Sickness
Depth
(metres)
Time
(minutes)
Breathing
Media
Total
Elapsed
Time (hr:min)
18
20
O2§
0:20
18
5
Air
0:25
18
20
O2
0:45
18
5
Air
0:50
18
20
O2
1:10
18
5
Air
1:15
18 to 9
30
O2
1:45
9
15
Air
2:00
9
60
O2
3:00
9
15
Air
3:15
9
60
O2
4:15
9 to 0
30
O2
4:45
In the Recompression Chamber at Welkom Hyperbaric Facility
At this point the DAN doctors recommend I did not dive for six months just in case. In it self this was not a terrible thing. In fact I could count myself very lucky not to have any permanent damage. However there was an added complication. About two years prior to this incident I was diagnosed with a probable PFO or Patent Foramen Ovale. This is a condition where the flap of tissue that divides the left atrium of the heart from the right atrium does not fully close within a few weeks of birth. What this means is that blood coming from the veins can pass directly into the arterial system. Along with this, un-oxygenated blood can go bubbles of nitrogen absorbed by the diver during a dive. It is estimated that about one in three people have a PFO (Alert Diver September/October 2004). In non-divers it is usually not a problem. However, given the possibility of bubbles moving into the arterial system and worse still, the brain, in divers it can be very dangerous.
Even so, based on their current body of knowledge about this condition, doctors cannot give an accurate assessment of the increased risk of acute decompression illness, or even the more serious arteriole gas embolism. PFO is still not regarded as a negative indicator for diving, although as I’ve said some doctors have reservations about it. DAN studies estimate that “the estimated risk of a DCI incident characteristic of those correlated with PFO is between 0.002-0.03 percent of dives (Alert Diver September/October 2004).”
I was advised by some of the most knowledgeable doctors I know to continue diving in the conservative manner I had been doing, very carefully. And this I did. Via the inter
net I found out that migraine with aura is often found in people with PFO. I also discovered a relatively simple procedure that can close the PFO and possible stop the migraines altogether (Windecker,ESC Congress,2003). As a result of this, and in the light of my recent ‘incident’, I decided to have the PFO closed. At least this would remove one more risk factor from my diving.
I met Dr Geoff Harrisburg at Sunninghill Clinic in February 2004. We chatted, and after doing an ultrasound investigation, he confirmed the PFO and agreed that given my history I should have it closed. The operation was scheduled for 2 March 2004. The procedure is a very modern form of heart surgery called a Trans-Catheter implant. As the name suggest, it involves implanting a small device in the heart to block the PFO. The device is a sort of two sided umbrella that is inserted via the large vein in one’s groin and then literally pushed all the way into your heart where one end is pushed through the PFO and then opened followed by the other side. The two sides of the umbrella form a substrate on which new tissue grows and thus seals the gap. Surprisingly enough, the entire procedure can be done under local anaesthetic. In my case however, the doctor wanted to test a new ultra-sound device that provides images from within the heart during the operation. Because of this I was placed under general anaesthetic.
Into The Deepest And Darkest Page 9
