Hypovolaemic Shock - the usual one we get to deal with. The volume of fluid circulating drops to a level that is lower than what the body needs in order to provide adequate "perfusion" (oxygenation of the tissues). The classic cause is heavy bleeding, both internal and external if the patient is unlucky. It can also be due to loss of fluid from large burns, and dehydration from getting too hot or a combination of pukeing/diarrhoea. Unfortunately one of the symptoms of shock is nausea, which doesn't help.
Anaphylactic Shock - the bee-sting allergy problem. Basically a severe allergic reaction. It can develop in within minutes or seconds as the body drastically over-reacts and the blood vessels dilate. The patient's airway has an annoying tendency to swell up, constricting their air supply and causing extreme panic. They need oxygen and an urgent injection of adrenaline, so it is important to notify HQ of the situation soonest.
Cardiogenic Shock caused by the heart not pumping enough blood to perfuse the tissues. This is fairly obviously part of the scenario we deal with as various forms of heart failure (myocardial infarction, congestive cardiac failure, heart disease etc.), and HQ are advised of the situation ASAP as per usual.
There are other forms of shock which are infrequently encountered by
the First Responder, at least in a form which has a practical treatment:
Toxic
Shock which is the result of an infection releasing a toxin that dilates
the circulatory system, dangerously lowering the blood pressure and causing
blood to pool. Neurogenic Shock is generally the result of
spinal trauma; the nerves are damaged and so the body's control over the
blood vessels goes up the creek. With these scenarios, we keep the patient
alive until paramedics arrive with suitable drugs.
But we must remember that shock can result from many things such as
illness, heart conditions, perforated ulcers, ectopic pregnancies, hyperthermia
- particularly with firemen wearing breathing apparatus or fighting bush
fires on hot days - and allergic reactions.
In the first stage of shock, called compensated shock, the body is making up for the loss of fluid by diverting blood from non-critical areas to the body core. What little blood it has, it pumps round like crazy to maintain the pressure. So as far as we can tell, the patient is fairly razzled (that's a technical term), has a high pulse of maybe 100 bpm, maybe has cold, paler, clammy skin. They may have slightly reduced capillary refill and feel nauseous or lightheaded. However, as we know very little about the normal state of our patient we often have to rely on deducing their state from the method of injury. Sometimes it is possible to ask Mum if the kid is usually as white a sheet, but the reply may be a little biased. A BP reading now will form a baseline for us, the ambulance and hospital people to compare things with. Oxygen will help keep the patient "compensated" for longer, but may interfere with the initial BP and pulse readings - whether this is important is a judgment call.
The body is preparing for a fight-or-flight reflex with a view to lying down and recuperating later. However, as more fluid is lost (30-40% of our 9-12 pints), the body fails to cope and we get into decompensated shock. At this point the patient's gallant attempts to look well start to fail, and the patient will start to look crook. The BP goes down, the pulse goes way up, breathing gets more rapid. The patient will look pale, and if not very hyperthermic, will sweat. Capillary refill will be noticeably slower and if they're not on oxygen now would be a really good time to give them lots. At 40% loss the patient becomes restless, agitated and irrational. The pulse is probably 120bpm+ and the systolic BP drops to less than 100mm Hg. They may gasp for air at this point, and things are not going well.
As the loss drops below 40% and heads to 50% the systolic pressure drops to 70mm Hg and below - internal organs start to get damaged at this point as they run in reverse. The radial pulse is going to be absent, and the carotid artery begin the last place the body will shut down may be the only palpable pulse site. The patient is probably going to pass out around now and will have blue lips. Respiratory distress, cardiac arrest and eventual death are the ultimate conclusion.
It is VERY IMPORTANT to remember that a person who is compensating
is not going into shock; they already are in shock and we treat them as
such.
Anaphylactic shock has some special rules. If we know the patient has been stung and is dangerously allergic to the stinging critter, they may have an Epi-pen for use in these situations - kids often have them kept in the school fridge. The patient should be encouraged to use it. If conscious, they will find it easier to breath in a semi-sitting position.
Otherwise, if the patient is conscious and has not got spinal, pelvic or serious leg injuries we place them in the shock recovery position - laying down on their back, raised legs with something soft underneath them.
If there are severe injuries to the legs, spinal or pelvic injuries, we put them in what we call the leave-them-as-you-found-them position - within reason of course - and try to work around them. Working in this case follows the SRABCS rules, probably including use of elevation and pressure to prevent external bleeding, and of course the rubber gloves are going to be essential here.
If the patient has heart trouble and their BP is dangerously low and/or
dropping, suggest that they do not use their GTN spray. GTN will drop their
BP further and may cause damage.
They may want a smoke. Smoking being a daft idea under the best of conditions; don't let them.
Watch the casualty carefully and take vital signs every 10 minutes if practical.
Be ready to do CPR and maintain life support.
Warmth
Air
Rest
Raise feet
Reassurance
This and other interesting documents can be found at http://family.gen.nz/launchpad