Voyaging medical questions


This is the time of year when I live far inland where the biggest backcountry risks are posed by avalanches and altitude illness. I am reduced to surfing the web for my virtual sea time and to keep in touch with what mariners are thinking. Fortunately, there is no shortage of thought-provoking forum discussion in the medical, health and safety sections of the various websites. Some have been bouncing around for years, and some are new. I’d like to offer my thoughts on a few of the comments and questions I’ve read recently. 

Is an AED now essential equipment aboard a boat? The automated external defibrillator (AED) is well documented as a life-saving tool in pre-hospital medicine. There are thousands of people still walking the earth today who would have died without an AED. But, thinking globally, one has to wonder how many lives would have been saved if the billions of dollars that have been spent on the manufacture and promotion of AEDs were spent elsewhere in health and safety, like relevant health education for school children or combating malaria. 

The AED question highlights the many ways that medical information, stories and statistics can be interpreted and spun. It also raises the difficult issue of how we choose to spend our limited resources. We tend to look for quick and well-defined responses to a perceived problem. It is much easier to donate an AED to a remote village than to design and deliver an educational program to school kids. It is much easier to publicize and celebrate a rare AED save than to track, measure and applaud the effect of health education on kids, their village and lives in the community over decades. 

An AED is designed to deliver an electric shock to a fibrillating heart, as occurs during some forms of heart attacks. In some of these cases, the shock will cause the heart to revert to a more effective rhythm, buying the patient a little time to get to a cardiologist and be stabilized. It is only one step in a chain of medical care including chest compressions, defibrillation and advanced medical care in a hospital. It is not a stand-alone treatment. 

Studies in urban areas have shown that a basic emergency medical technician with an AED and an ambulance produces higher cardiac arrest survival rates than paramedics with all of the drugs and sophisticated equipment that they have at their disposal. This is not because EMTs are better at defibrillating than paramedics, it is because EMTs cannot do much more about cardiac arrest than defibrillate, ventilate and drive. They get to the hospital faster. 

Early access to a defibrillator, ideally within five minutes, is the key to successful defibrillation. Early access to hospital care is the key to survival. Some of the people selling AEDs claim success rates of more than 90 percent. They are drawing their line of success at restoration of a pulse in specific cases of ventricular fibrillation. Most of us would prefer to draw the line at actually walking out of the hospital alive. That survival-to-discharge rate in the U.S. is 10.4 percent. The overwhelming majority of these saves occur in urban areas. The number is far lower for rural areas and almost zero in remote locations with no access to advanced medical care. There is a big difference between being defibrillated and being saved.

Many years ago I was challenged by a salesman who asked, “Even if there is a 1 in 100,000 chance of saving a life, isn’t that still worth carrying the AED?” For the average sailor on a budget, my answer is still no. In spite of the fact that AEDs have become smaller, easier to use and less expensive, the demographics of successful outcome have not changed. 

Defibrillators still retail for $1,200 and up. There are far too many other pieces of equipment — medical and otherwise — that have a far better chance of saving your life at sea. Spending money on your own medical and health education would have life-saving benefits far beyond your ability to respond to ventricular fibrillation. Better yet, educate your kids and the benefits will continue for decades to come. This is a good place to think globally about your little ship, its crew and where to spend your limited resources.

On the other hand, if you run a head boat, ferry or cruise ship you should definitely buy a defibrillator. If anyone dies on board of anything cardiac, you may be viewed as negligent if you don’t have one. The public has come to expect it, and most of these vessels either have advanced medical care aboard or operate within close range of a 911 response, making the cost-versus-benefit ratio slightly more favorable. Also, the larger number of people on board increases the probability that it will be used. 

For voyagers, though, even powerful and easy-to-use AEDs, like this model, are not a standalone treatment.

Courtesy CU Medical Systems

Is Malaria is easily prevented and cured? Easily prevented? Yes, just stay far out to sea. It is well known that land is expensive and dangerous. The associated stagnant water breeds the most lethal animals on the planet. Mosquito-borne illness kills millions of people annually, and sickens and annoys tens of millions more. To completely avoid exposure, you should only come ashore in the higher latitudes when the land is completely frozen. 

Easily cured? Not always. The treatment of uncomplicated falciparum malaria is actually rather complicated. There are various combinations of medication discussed for different parts of the world and depending on what might have been taken for prophylaxis. If not completely treated, the disease can reoccur months later. In some parts of Southeast Asia, the parasite is developing resistance to all known treatments. Not getting malaria in the first place is clearly the preferred strategy. 

The Anopheles mosquito, the primary vector for malaria, is usually active at dawn and dusk — and sometimes all night. The Aedes mosquito responsible for the spread of Zika, chikungunya, dengue and yellow fever feeds at dawn and dusk and sometimes all day. In the tropics, at least, there really is no safe time of day or off-season. Anti-mosquito defense needs to be serious and full time. 

Tactics include armor, repellents, decoys, counterattacks and prophylaxis. Tight-weave insect-proof clothing is annoying in hot weather, but so is a fever of 103° F. It is well worth finding something mosquito-proof that looks good on you for dinner ashore. On board, high-quality hatch screens and bed nets can make the difference between a good night’s sleep and unimaginable irritation, not to mention febrile illness. This would be a good place to spend some of that money you’ve saved by not buying a defibrillator. 

The best mosquito repellents for skin application contain DEET or Picaridin in concentrations around 30 percent. Although some research suggests that mosquitoes can learn to ignore them, nothing else currently comes close in effectiveness. Both are very safe when used as directed. Another useful chemical, permethrin, is both repellent and an insecticide and best used on or soaked into clothing, companionway screens and bed nets. You can purchase permethrin by the bottle and DIY impregnate all kinds of fabrics. It will last months and survive multiple washings.  

Decoys and traps emitting carbon dioxide or other attractants are an interesting idea for a boat. One wonders if using a decoy at anchor would just attract more mosquitoes from shore, but the comments from mariners who have used them are generally positive. It’s interesting to note that studies suggest foot odor is particularly attractive to mosquitoes — this may explain why they always seem to get at your ankles while you are busy defending everything else. 

A counterattack usually involves using poison in concentrations high enough to kill mosquitoes but too low to kill you. In high-risk anchorages it might be worth spraying the living space aboard while the crew is ashore to allow most of the insecticide to dissipate before the humans return. This will kill mosquitoes hiding and resting in cabin and hull spaces.  

Another form of counterattack involves the use of a battery-charged electrocution device that looks something like a small tennis racket (not to be confused with a defibrillator). The defendant waves it about in the air until a sharp snap and puff of smoke signals the demise of at least one winged assailant. Using it is probably ineffective at preventing the spread of malaria, but still somehow deeply satisfying. 

Prophylactic medication is used to help prevent infection if avoidance measures fail. There is always some risk in taking drugs, and some of those used for malaria prophylaxis have significant side effects. In malaria-endemic areas, the benefits of prophylaxis outweigh the risks. The choice of medication depends on patient and prescriber preference, risk of exposure, interaction with other medications, potential adverse reactions and the area of the world being explored. 

One way for voyagers to stay healthy is to avoid infection in the first place. In areas with mosquitoes that carry infectious diseases, netting and screens can keep insects out of the boat.

Courtesy Mosquito Curtains

Remember, however, that access to malaria prophylaxis in no way diminishes the importance of mosquito avoidance and control. Antibiotics are useless in preventing and treating the mosquito-borne viral diseases. Dengue, while rarely fatal, can be pretty miserable to live through. 

And beware, as is typical with anything that scares people, there are lots of “miracle cures” and sure-fire protections offered to combat malaria. Rest assured that if this disease really could be cured with sodium chlorite and whipped cream, the World Health Organization would be all over it. Sadly, thousands die every year by being lured away from more effective treatments by false promises.   

We carry two antibiotics: Cipro for the real bad stuff and Z-Pak for the typical flu, etc. Is that right? Unfortunately, there is a lot of bad stuff that Cipro doesn’t cover well and azithromycin (Z-Pak) doesn’t treat the flu. As illustrated by malaria, pathogens are continually evolving ways to avoid or defeat the antibiotics we create to kill them. The excessive and inappropriate use of antibiotics is the major contributing factor. Practitioners in the developed nations, particularly the U.S., find it easier to satisfy the patient with a prescription rather than explain why antibiotics won’t help cure their viral respiratory infection. Resistance is also a problem in countries where antibiotics are sold over the counter. 

Offshore, or in an anchorage in the Tuamotos, preventing global antibiotic resistance may not be your prime concern. In a remote environment, the benefits of antibiotics definitely outweigh the risk and cost if they are used appropriately. Deciding on which ones should be stocked depends on current trends in resistance, travel destination, anticipated side effects and interaction with other medication that you may be using. Selection should be done with the help of a medical practitioner familiar with you and your travel plans, and with access to the latest information from reliable sources. If you are not lucky enough to have a bluewater doctor, you should take the time to describe your world afloat, including capabilities and limitations, to the medical professional trying to help you. As illustrated by the AED, what makes sense ashore may not work very well at sea. 

Doxycycline, for example, is a broad-spectrum antibiotic active against some forms of malaria, Lyme disease and some of the bacteria that cause respiratory infections, urinary tract infections, cholera, plague, syphilis and intra-abdominal infections like appendicitis — a wonder drug, it would seem. Unfortunately, doxy can be hard on the stomach and esophagus, and can cause severe photosensitivity reactions in people exposed to the sun. Not so wonderful for sailors, sometimes. 

On a remote voyage, it is wise to carry several different antibiotics chosen to span the spectrum of anticipated pathogens and allow you to avoid certain adverse effects when necessary. You can cover almost everything treatable with four different types. You should also consider carrying a broad-spectrum antibiotic that can be given by intramuscular injection in case the patient cannot swallow oral meds or their GI system is not working well.  

To minimize the risks associated with antibiotics or any other drug, you should make it your business to learn as much as you can about how they work and what they are really used for. For any medication that you carry, you should know the indications, contraindications, side effects, precautions, dose and route. If you are not familiar with these terms, look them up. It would be a good way to enhance your medical education and allow you to better communicate with the practitioner helping you build your medical kit. 

Is anybody cruising without a spleen? Well, that one caught my attention because I cruise without a spleen. Ashore, my chances of dying from overwhelming post-splenectomy sepsis (OPSS) are about the same as dying in a car accident. Not high, but not unusual. At sea, my risk of dying of OPSS is increased by being remote from medical care, while my chance of developing OPSS is decreased by not being exposed to as many pathogens. So, am I safer at sea or ashore? This highlights the interesting world of medical risk assessment.

If you choose to voyage with a chronic medical condition, you should make it your business to know as much as you can about your condition and its management. Consult a practitioner expert in your disease. Combine that expertise and advice with what you have learned and your expertise in the marine environment to develop a good sense for the risk you are taking and how you might reduce it. This will be a lot of work and you might have to look far and wide for good information, but it could save your life. 

Repellents containing DEET can keep mosquitoes from biting.

Courtesy Sawyer Products

I was amazed to discover how little the practitioners in my area know about life without a spleen — myself included. There was little useful information from the surgeon who removed it, and not much more from my primary care physician. I had to research it myself. 

The most useful advice came out of the U.K. and Australia. I now know what vaccines I need, what antibiotics to carry and when to use them, and especially to avoid land where I might encounter babesiosis and falciparum malaria. Much to her consternation, I no longer allow my dog to give happy kisses or sympathetic hand licks (re: Capnocytophaga canimorsus). 

I have become my own expert on the subject, as you certainly can with whatever condition you might be dealing with.  

And don’t forget to write it down. Carry a summary of your medical history, any medications taken, vaccination records, recent laboratory reports, electrocardiogram and a digital copy of  recent chest x-rays. This information can be extremely helpful and save you a lot of expense and trouble when far from home. If you don’t have a spleen, for example, your blood count and cell morphology will look a little odd. It would be nice to have data from the past for comparison so the doctor in Whangarei can tell the difference between a new problem and your normal odd self. 

Electrocardiograms and chest x-rays are particularly important. I’ve spent many hours trying to save a patient a multi-thousand-dollar work up by accessing an old ECG. This always happens on a weekend or holiday when their doctor’s office is closed. I can’t tell if that little elevation or upside-down wave in the tracing is new or old, especially if they have a history of heart problems. Please, carry a copy of yours. It could save a lot of angst, and maybe a long flight to Australia. 

On a final note: It has always amazed me that mariners who can understand complex navigational systems, fix diesel engines and debate the vectors and forces affecting anchoring systems can be so naive about medicine. It seems that the amount of misinformation, bad advice and just plain fiction found in the medical sections of the various cruising forums exceeds that of any other topic (with the possible exception of relationship advice). I suspect that this is a reflection of the basic education on the subject that we didn’t get as school kids, at least in the U.S. When we go to sea or any other remote place where we rely on ourselves for every life skill, it would seem to be an important deficiency to correct.

Jeff Isaac PA-C is the curriculum director for Wilderness Medical Associates International, a licensed captain, and an experienced sailor. He is the primary instructor for Offshore Emergency Medicine, the WMA training program designed for cruising sailors and marine professionals. When “feet dry,” he practices emergency medicine in Crested Butte, Colo.

By Ocean Navigator