Wilderness and Rescue Medicine 7th Edition Jeffrey Isaac, PA-C and David E. Johnson, MD

Section VII: Roles, Responsibilities, and Technology 243

Subcutaneous fluid replacement (hypodermoc- lysis) is another option, but somewhat slower. This technique is very safe and low risk and can be easily accomplished with minimal training. It is a good option to consider aboard ship, for example, where carrying several liters of IV fluid is practical and the probability of dehydration from seasick- ness is high. Another example might be a vehicle supported bicycle or trekking trip. If fluid replacement is required during evacua- tion, a gravity-fed IV or sub cutaneous drip will be difficult to maintain. There are various pressure and power infusers that can be packaged with the patient, eliminating the need to hang the fluid bag above the litter. A better option is to use periodic bolus infusions administered while the litter team is taking a rest. This can be accomplished through intermittent connection to an IV heparin lock or via an intact system with the IV line closed while the patient is being carried. Fluid bolus can also be given subcutaneously in the same way that veterinarians sometimes do for cats and dogs. Aggressive fluid replacement for shock from uncontrolled bleeding can be dangerous when surgical care is not immediately available. The increase in blood pressure with volume expansion may dislodge clots causing bleeding to become worse. Additionally, too much fluid can dilute clotting factors. Current guidelines for hemor- rhagic shock usually call for a limited bolus of up to 500 ml followed by a slow drip until hemostasis is confirmed. Considering its weight versus its potential for benefit, packing more than a liter of normal saline or lactated Ringer’s into the backcountry is justified only when responding to a known medical problem where significant dehydration is likely to be on the problem list. Risk Versus Benefit The most basic risk in the use of any device is that it will take up space, weight, and money that could be better used for something more likely to reduce risk and improve outcome. The most obvi- ous example is the EMS crew running into the backcountry loaded down with drugs, monitors, defibrillators, and jump kits but no head lamps,

food, water, or rain gear. The corollary, of course, is the SAR crew arriving on scene fully prepared to weather the night, but without any way to treat the patient’s open fracture and pain, or prevent a serious infection. A more insidious form of risk is presented by technology in its tendency to distract you from good basic assessment and treatment. Your car- diac monitor may show normal sinus rhythm, but does it really change the field treatment of a 65-year-old man with substernal chest pain and sweating? Your pulse oximeter may read 75%, but does this really change your response to a patient with normal mental status, good skin color, and no apparent respiratory distress? In a field set- ting, diagnostic technology like this can confuse as often as confirm the pattern you’ve observed. A good question to ask when deploying diagnostic instrumentation is: what am I going to do with the information it gives me, and what difference will it make in my treatment? In the remote setting, the answer is often not much .