After the fire is knocked down the rehab sheet comes over to you. Joe, the engineer off of Truck 3, standouts out on the list as his blood pressure is showing 160/100.
Joe looks fine and when you talk to him he says he feels fine. The paramedics appear concerned but vague or non-committal about the risk of letting Joe continue the shift or continuing to work on the scene.
This is a common response in many instances where a full set of vitals are recorded as part of the rehab process. Indecisiveness, turning a blind eye or lack of knowledge to the risk and the NFPA standard raises the probability of an eventual bad cardiovascular outcome.
Blood pressure surveillance in rehab operations is an area in the fire service that has a consistent “normalization of deviance” from NFPA 1581, 1582 and 1500. The American Heart Association defines hypertension as a blood pressure of 140/90.
Hypertension identified in rehab that has not been addressed by the department’s wellness physical, or frankly ignored when recorded in the rehab operations on the fireground, do not display obvious consequences. Yet it inflicts damages that will ultimately impair firefighter health.
Diuretics
Hypertension was coined as a silent killer before the marketing on carbon monoxide made it a prominent silent killer, as people died from a single exposure verses repeated cumulative exposures.
Hypertension is a silent killer because most patients with high blood pressure have no symptoms to alert them. But over time, high blood pressure increases the risk of serious problems such as stroke, congestive heart failure, heart attack and kidney failure.
The 2007 NFPA standard on controlling blood pressure is clear. It is helpful to understand the four common methods to control blood pressure and their effects on firefighters specifically.
The use of diuretics or water pills, medications commonly called thiazides, is often a first-line medication prescribed by physicians. Diuretics work by flushing excess water and sodium from the body, thus lowering blood pressure. This and lifestyle changes may be enough to control blood pressure.
A diuretic is not a good high blood pressure medication for firefighters because it causes dehydration. Arriving at a fire already dehydrated and incurring the thermal stress and water loss via sweat can wreak havoc on a firefighter. Fatigue, dizziness and confusion are all dangerous symptoms for a firefighter on an interior attack or working on a ladder or roof.
Beta and calcium blockers
Beta blockers control blood pressure by blocking certain nerve and hormonal signals to the heart and blood vessels, thus lowering blood pressure. Frequently prescribed beta blockers include metoprolol (Inderal, Lopressor, and Toprol XL), propranolol (Inderal), nadolol (Corgard) and atenolol (Tenormin).
Beta-blocker medication has been shown to increase the risk of heat stroke. Firefighter turnout ensembles work by drawing the heat off of the body’s core and periphery. The arms and legs play a large role is creating more surface area to draw the heat into the vapor barriers and cool the firefighter.
For this to occur, the heart rate needs to increase to circulate the blood to the arms and legs to help dissipate the heat. When a firefighter is on a beta blocker the heart rate cannot increase, therefore, the turnouts cannot function properly.
Calcium channel blockers are a third class of medications to prevent hypertension. These prevent calcium from going into heart and blood vessel muscle cells. This causes the cells to relax, which lowers blood pressure.
Frequently prescribed calcium channel blockers include amlodipine (Norvasc), diltiazem (Cardizem, Dilacor XR) and nifedipine (Adalat, Procardia).
Word of caution
Firefighters needs to be cautious about what type of calcium channel blocker they use. There are slow, medium and fast calcium channels and each has a different effect.
Slow calcium channels effect blood vessels and have the same effects as angiotensin-converting enzyme inhibitors, these include the medications of Procardia and Norvasc. The medium calcium channels, which have some effects on the heart and the blood vessels, are effected by Cardizem. The fast calcium channels are in the heart and are effected by antihypertensive like Verapamil.
The preferred antihypertensive for firefighters are angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers. These allow blood vessels to widen or relax by preventing the formation of a hormone called angiotensin.
Frequently prescribed angiotensin-converting enzyme inhibitors include enalapril (Vasotec), lisinopril (Prinivil, Zestril) and ramipril (Altace). Frequently prescribed angiotensin II receptor blockers include losartan (Cozaar), candesartan (Atacand) and valsartan (Diovan).
These medications work by vasodilating or dilating blood vessels. Vasodilation pushes blood outward to the skin; in a firefighting scenario can actually aid the turnout ensemble making the cooling process more efficient.
Preventive medicine
The 2013 NFPA 1581 Standard on Comprehensive Medical Programs for Fire Departments Section 9.16.9 covers the use of antihypertensive medication. It specifically states the medications not recommended and specific job task that are impacted that can compromises firefighter safety.
The rehab officer needs to ensure that blood pressures are accurately measured with the correct size of cuffs and ensuring that the meters are calibrated. A first blood pressure should always be manual and then it is acceptable to use a machine to measure blood pressure.
There are a lot of preventive measures to be taken prior to having a blood pressure be flagged in the rehab unit. Diet is a simple preventive measure. Reducing the salt intake, which is significant in diet soda, or finding a salt substitute is good.
Routine exercise and weight management is also another preventative measure. Simply walking 30 minutes a day, three times a week can help prevent weight gain and is shown to reduce hypertension.
Fire departments need to set guidelines for screening and enforce firefighter follow up and monitoring by a department physician to contain and control blood pressure.
It is critical to have a fire department physician that understands how heat stress in a turnout ensemble influences the antihypertensive that a firefighter may be prescribed.
