Lecture 1 Acid Bases

LECTURE 1 ACID BASES • learn how to convert lab values to words • the rule of the B’s! = if the pH and the BiCarb are both in the same ! direction -> metabolic! Hint: draw arrows beside each to see directions! * down = acidosis! * up = alkalosis! - respiratory -> has no b in it; if in other directions ! (or if bicarb is normal value)! - KNOW NORMAL pH, BiCarb, CO2 ! • Hint: DON’T MEMORIZE LISTS…know principles (they test knowledge of principles by having you generate lists..) - for “select all” questions! - ex. in general/principle what do opioids/pain ! meds do? = sedate you, CNS depressors! * ex. what does dilaudid do? don’t memorize specifics ! or a list of dilaudid, know principles of opioids (such ! as sedation, CNS depression -> lethargy, flaccidity, ! reflex +1, hypo-reflexia, obtunded)! - boards don’t test by lists because all books/! classes have different lists! • principles of S&S acid bases: as the pH goes so goes my patient (except K+)! - pH up = PT up -> body system gets more ! irritable, hyper-excitable (EXCEPT K+)! -> alkalosis - think of a body system and go ! high: hyper-reflexive (+3, +4 [2 is normal]), ! tachypnea, tachycardia, borborygmi, seizure! - pH down = PT down -> body systems shut ! down (EXCEPT K+)! -> acidosis - think of a system and go low: ! hypo-reflexive (+1, 0), bradycardia, lethargy, ! obtunded, paralytic illeus, respiratory arrest • ex. which acid-base disorders need an ambu-bag at the bedside? = acidosis (resp. arrest) • ex. which acid-base disorders need suction at the bedside? = alkalosis (seize and aspirate) • Mac Kussmaul - Kussmaul’s (compensatory respiratory mechanism) is only present in only 1 of the 4 metabolic (acid-base) disorders! * M = metabolic AC = acidosis! • most common mistake with select all questions = selecting one more than you should (stop when you select the ones you know! don’t get caught up on the “could be’s”) • Hint: don’t select none or all on select all that apply questions (never only one and never all) • Causes of Acid-Base Imbalance:! - scenarios and what acid-base disorder would ! result (what would cause an imbalance)! ** DON’T MIX UP S&S and CAUSATION! - often what causes something is the opposite of the S&S! - ex. diarrhea will cause a metabolic acidosis but once ! you are acidotic your bowel shuts down and you get a ! paralytic illeus • when you get scenarios: ! -> if it’s a lung scenario = respiratory! - then check if the client is over-ventilating ! (alkalosis) or under-ventilating (acidosis)! - remember to look at the words (ex. over, under, ! ventilating) -> “as the pH goes so goes my PT”! -> VENTILATING DOESN’T MEAN RESPIRATORY ! RATE; resp. rate is irrelevant w/ acid-base, ! ventilation has to do with gas exchange not resp. ! rate (look at the SaO2 -> if your resp. rate is fast ! but SaO2 is low you are under-ventilating)! -> ex. PCA pump - What acid-base disorder ! indicates they need to come off of it? = respiratory ! acidosis (resp. depression -> resp. arrest)! —> if it’s not lung, it’s metabolic • metabolic alkalosis - really only one scenario = if the PT has prolonged gastric vomiting/suctioning! - because you are losing ACID! * ex. GI surgery w/ NG tube with suctioning for ! 3 days; hyperemesis graviderum! - otherwise everything else that isn’t lung you ! pick metabolic acidosis (DEFAULT)! * ex. hyperemesis graviderum w/ dehydration ! acute renal failure, infantile diarrhea • remember, you only have 4 to pick from:! - respiratory alkalosis - respiratory acidosis! - metabolic alkalosis - metabolic acidosis • pay more attention to the modifying phrases than the original noun! - ex. person w/ OCD who is now psychotic (psychotic ! trumps OCD); hyperemesis with dehydration (pay ! attention to dehydration) VENTILATION • ventilators -> know alarm systems (you set it up so that the machine doesn’t use less than or more than specific amounts of pressure)! a) high pressure alarm = increased resistance ! to airflow (the machine has to push too hard to ! get air into lungs)! - from obstructions: ! i. kinks in tubing (unkink it)! ii. water condensation in tube (empty it!)! iii. mucous secretions in the airway (change ! positions/turn, C&DB, and THEN suction)! *** suction is only PRN!!!! -> priority questions = you would check ! kinks first, suction is not first! ! b) low pressure alarm = decreased resistance ! to airflow (the machine had to work too little ! to push air into lungs)! - from disconnections:! i. main tubing (reconnect it duh!)! ii. O2 sensor tubing (which senses FiO2 at ! the airway/trach area; black coated wire ! coming from machine right along the ! tubing - reconnect!) • ventilators -> know blood gases! - resp. alkalosis = ventilation settings might be ! set too high (OVER-VENTILATING)! - resp. acidosis = ventilation settings might be set ! too low (UNDER-VENTILATING) • ex. weaning a PT off ventilator -> should not be under-ventilated, they need the ventilator; if they are over-ventilating then they can be weaned • never pick an answer where you don’t do something and someone else has to do something