ITE CA-2 formulas plus (from TL) Flashcards
alveolar gas equation
PAO2 = (Patm - PH2O) FiO2 - PaCO2/RQ Patm is the atmospheric pressure (at sea level 760 mm Hg), PH2O is partial pressure of water (approximately 45 mm Hg). FiO2 is the fraction of inspired oxygen. PaCO2 is partial pressure of carbon dioxide in alveoli (in normal physiological conditions around 40 to 45 mmHg). RQ is the respiratory quotient. The value of the RQ can vary depending upon the type of diet and metabolic state. RQ is different for carbohydrates, fats, and proteins (average value is around 0.82 for the human diet).
formula plasma osmolarity equation
Plasma osmolality (Posm) = 2 x [Na] + [glucose]/18 + blood urea nitrogen/2.8
oxygen content equation
OXYGEN CONTENT: CaO2 = SaO2 x Hgb x 1.34 + (PaO2 x 0.003) CaO2 = arterial oxygen content (mL/dL) SaO2 = arterial oxygen saturation **(should be 0.93-1)** Hgb = hemoglobin concentration (g/dL) PaO2 = arterial partial pressure of oxygen (mm Hg) 1.34 is used because it is the oxygen carrying capacity of hemoglobin and 0.003 is used as it is the solubility coefficient of oxygen in plasma
oxygen delivery equation
OXYGEN DELIVERY: DO2 = CaO2 x CO x 10 CaO2 = arterial oxygen content CO = cardiac output (which is heart rate x stroke volume)
formula for SVR equation
SVR = [80 * (MAP – RAP)] ÷ CO = [80 * (100 – 5)] ÷ 5 = 1520 dynes * sec/cm^5 Where: MAP = mean arterial pressure (mm Hg) RAP = right atrial pressure (mm Hg), central venous pressure is commonly substituted for RAP CO = cardiac output (L/min) 80 = conversion factor which changes mm Hg/L/min (Woods unit) to dynes * sec/cm^5
formula for MAP equation
MAP = [(1/3) * systolic pressure] + [(2/3) * diastolic pressure] = [(1/3) * 120 mm Hg] + [(2/3) * 90 mm Hg] = 100 mm Hg
MPAP formula equation
mean pulmonary arterial pressure (MPAP) must be calculated since it is not given directly: MPAP = [(1/3) * systolic pressure] + [(2/3) * diastolic pressure] = [(1/3) * 24 mm Hg] + [(2/3) * 12 mm Hg] = 16 mm Hg
PVR formula equation
PVR = [80 * (MPAP – PAOP)] ÷ CO = [80 * (16 – 8)] ÷ 5 = 128 dynes * sec/cm^5 Where: MPAP = mean pulmonary arterial pressure (mm Hg) PAOP = pulmonary artery occlusion pressure or pulmonary capillary wedge pressure (mm Hg) CO = cardiac output (L/min) 80 = conversion factor which changes mm Hg/L/min (Woods unit) to dynes * sec/cm^5
SvO2 equation
The Fick equation reveals SvO2 = SaO2 - [VO2 ÷ (CO * Hgb * 1.36)] Where: SvO2 = mixed venous oxygen saturation SaO2 = arterial oxygen saturation VO2 = total body oxygen consumption CO = cardiac output Hgb = hemoglobin concentration
law and formula regarding flow equation
The Poiseuille Law states that: Q = ΔP(π * radius4) / (8 * viscosity * length) Where: Q = flow, Δ = change in, P = pressure, π = 3.14159… (the mathematical constant).
CPP formula equation
CPP = (Aortic DBP – LVEDP)
Respiratory system compliance equation
1/CRS = 1/CL + 1/CCW Where C is compliance, RS is respiratory system, L is lungs, and CW is chest wall.
static compliance formula equation
CS = VT ÷ (PPL – PEEP) Where: CS is static compliance, VT is tidal volume, and PPL is plateau pressure. The static compliance of the respiratory system indicates the “stiffness” of the respiratory system, which includes the lungs and chest wall. It is determined at the end of inspiration when there is no airflow, hence “static.”
dynamic compliance formula equation
CS = VT ÷ (Ppeak – PEEP) Where: CS is static compliance, VT is tidal volume, and Ppeak is peak pressure.
Elastance formula equation
Elastance is the inverse of compliance: E = ΔP/ΔV.
The standard error of the mean (SEM) can be calculated by equation
The standard error of the mean (SEM) can be calculated by dividing the standard deviation (SD) by the square root of the sample size (n). SEM = SD / sqrt(n)
Power equation
Increasing the alpha (type I error/false-positive) will increase the power. The larger the alpha, the lower the chance of a false-negative conclusion (type II error/beta). Conversely, increasing the beta will decrease the power. Power = 1 - beta.
Benzos in pregnancy
Midazolam is a benzodiazepine which should be avoided during pregnancy, especially early in pregnancy when anatomical structures are developing. Use during the third trimester is associated with floppy infant syndrome and significant neonatal withdrawal symptoms.
Similarities in the resuscitation of adults, children (age 1 year to puberty), and infants (under one year, not including newborns):
Similarities in the resuscitation of adults, children (age 1 year to puberty), and infants (under one year, not including newborns): Initial assessment of the patient: check for responsiveness, breathing, and pulse (spend no more than 10 seconds to do the pulse check). For witnessed collapse, if the rescuer is alone, a mobile device may be used to activate the emergency response system (ERS) and call for an automatic external defibrillator (AED). If no mobile device is available, the rescuer may leave the patient to activate the ERS and obtain the AED. Initiate compressions as soon as possible. When only one rescuer is present, use a compression-ventilation ratio of 30:2 until an advanced airway can be obtained. The compression rate is 100-120 compressions a minute. Once an advanced airway is in place, breaths may be given once every six seconds, including during compressions.
Differences between collapesd adults and the pediatric population (children and infants):
Differences between adults and the pediatric population (children and infants): In an unwitnessed collapse of an adult, proceed the same as a witnessed collapse: the rescuer may use a mobile device or leave the patient to activate the ERS and obtain an AED. However, in an unwitnessed collapse of a child or infant, the rescuer should give two minutes of CPR prior to calling or leaving to get help. Whether there are one or two rescuers, the compression-ventilation ratio without an advanced airway in adults is 30:2. If there are two rescuers in a child or infant, the compression-ventilation ratio is 15:2 instead of 30:2 (one-rescuer scenario). The compression depth for adults is at least 5 cm. In children, it is about 5 cm and at least one-third of the anterior-posterior (AP) diameter of the chest. In infants, it is about 4 cm and at least one-third of the AP diameter of the chest.
The __________ test is used to compare data that are considered nominal (categorical) or ordinal
The chi-square test is used to compare data that are considered nominal (categorical) or ordinal in order to determine whether observed frequencies are significantly different from expected frequencies. Nominal data are characterized by non-ordered responses such as gender, eye color, occupation, etc. Ordinal data are characterized by ordered response categories such as pain scores, annual income ranges, etc
Fent patch contraindications
Transdermal fentanyl is an excellent treatment option for chronic pain. Transdermal fentanyl is contraindicated for patients with acute pain or any pain state that requires rapid dose adjustments or any pain states that have states of pain-free intervals since the risk of respiratory depression is high.
Incidence and risk factors of neg pressure pulm edema
Negative pressure pulmonary edema has an incidence of 0.05-0.1% in all general anesthetics. Risk increases to 4% if airway obstruction occurs in a spontaneously breathing patient. Other risks include young age, male gender, physical fitness, and HEENT surgery
Bradycardia following spinal anesthetic
Bradycardia following spinal anesthetic injection is more common in patients with high baseline vagal tone, anesthetic levels above T5, and is associated with decreased cardiac preload Use epi early
Brainstem ischemia may lead to apnea.
Brainstem ischemia may be the result of hypotension and leads to apnea.
Cardiac acceleration fibers
When a sympathetic block reaches the level of T4, the sympathetic cardiac accelerating fibers begin to be blocked. The cardiac accelerating fibers originate from T1-T4 spinal nerves. When these fibers are blocked the heart rate will begin to slow. Effective treatments for bradycardia resulting from blockade of the cardiac accelerating fibers include atropine and epinephrine.
Bainbridge reflex
Decreased cardiac preload can cause bradycardia as a result of decreased stretch of the myocardium. Sympathectomy following spinal anesthesia results in a decrease in systemic vascular resistance and decreased venous return. Preload in the heart causes stretch of the myocardium, which increases intrinsic activity of the heart (Bainbridge reflex). When preload falls, the intrinsic depolarization of the SA node slows resulting in another cause of bradycardia following spinal anesthesia.
Bezold–Jarisch reflex
Bezold–Jarisch reflex (also called the Jarisch-Bezold reflex or Von Bezold-Jarisch) involves a variety of cardiovascular and neurological processes which cause hypopnea (excessively shallow breathing or an abnormally low respiratory rate) and bradycardia (abnormally low resting heart rate).
What is the active metabolite of morphine and why does it matter
Morphine 6-glucuronide is an active metabolite of morphine which can result in respiratory depression especially in patients with impaired renal function.
Meperidine metabolite
Normeperidine is a metabolite of meperidine after hepatic metabolism. Normeperidine produces CNS stimulation manifesting as myoclonus and seizures. This is particularly important in patients with impaired renal function since normeperidine can accumulate.
What is contraindicated if recent intravitreous gas injection and for how long
Nitrous oxide administration should be avoided for five days after intraocular air injection, 10 days after sulfur hexafluoride injection, or 30-90 days or longer after other perfluoropropane injection. This is because of blood:gas partition coefficient differences, which allows for nitrous oxide to readily diffuse into and expand the intraocular gas bubble.
CRPS types
CRPS is divided into two types. In type 1 there is no evidence of nerve damage, and in type 2 there is documented evidence of nerve damage.
Output equation given: carrier gas ml/min vapor pressure barometric pressure
Output = Carrier gas X vapor pressure/barometric pressure - vapor pressure Output = 100 X 150/750-150 = approx 25 ml/min (vapor) 25 ml/min output / 5000 ml/min FGF - 0.005 or 0.5%
How long wait after MI for for elective noncardiac surgery.
Remember: After an MI wait 14 days after balloon angioplasty, 30 days after BMS, 60 days if no coronary intervention, and 180 days after DES for elective noncardiac surgery.
FeNa formula
[(UNa)/(UCr)]/[(PNa)/(PCr)] x 100 = [(PCr x UNa ) / (PNa x UCr)] x 100
How to calculate what percent of gas someone is inhaling
