Exam 3 Flashcards
Diaphragm
Primary muscle of respiration
Diaphragmatic Hernia
GI organs migrate into the thoracic cavity through esophageal hiatus
Dx: No heart sounds on one side of chest or may hear gut sounds
Tx: Sx- must use ventilator
Spinal Cord Injury
Cervical vertebrae
Can’t use phrenic nerve-innervates the diaphragm
Pleura
Serous membrane that lines the thoracic cavity
Lined with simple squamous epithelium- movement
Mucous/goblet cells reduce friction
Parietal: lines the thoracic wall
Visceral: lines the organs within the thoracic cavity
Mediastinum
Serous membrane that divides left and right side of lungs
Prevents both lungs from collapse and infection
Intrapleural Space
Necessary to inflate lungs
Negative pressure
Vacuum
No air (Shouldn’t contain anything in this space)
Trachea/Bronchial Tree
Airway
O2 inhaled, C02 exhaled
Aspiration Pneumonia
Inflammation of the lungs caused by inhalation of foreign substances
Bronchioles
Lined with smooth muscle-involuntary
Alveolar Sacs
Lined with simple squamous epithelium
Surrounded by yellow elastic connective tissue
Gas exchange occurs here
Emphysema
A condition in which the alveolar sacs are damaged resulting in a decrease in pulmonary compliance (measure of the lungs ability to stretch and expand)
Tx: Oxygen therapy –> only adds O2 to system but does not help flush out expired CO2
Respiration
Inhalation: active process, contraction of muscles, intercostal, diaphragm pulled caudal into abdomen
Exhalation: passive process, muscles relax, diaphragm pulled cranial (help force CO2 out)
Composition of Air:
>02=21%, N2=79%, CO2=<1% (300 ppm)
Acid/Base Balance
pH of blood: 7.35-7.45
Lungs: When CO2 is increased –> pH decreases –> K+ in blood
Kidneys: When NaHCO3 is increased –> K+ in blood –> HR decreases
*Hyperkalemia –> Bradycardia
Pneumotaxic Center
Nuclei in brain stem
Measures CO2 levels
CO2 is what drives respiration
Tidal Volume
10-15 ml/kg
Amount of air contained in one entire breathe
Minute Volume
Tidal vol. X RR
Amount of air contained one one minute worth of breathing
Gas Exchange in the Alveoli (Capillary)
Low in CO2:
-pO2- 40 mmHg
High in CO2
-pCO2- 46 mmHg
Gas Exchange in the Alveoli (Alveoli)
Low in CO2
-pCO2- 40 mmHg
High in CO2
-pO2- 100mmHg
*Termed ETCO2 (end tidal CO2)
Should be 25-45 mmHG
Respiratory Alkalosis
Respiratory alkalosis is a primary decrease in carbon dioxide partial pressure (Pco2) with or without compensatory decrease in bicarbonate (HCO3−); pH may be high or near normal.
*Eliminating too much CO2
High pH
Low pCO2
Low HCO3- kidneys excrete bicarbonate
Caused by: Hyperventilation, iatrogenically during anesthesia
Respiratory Acidosis
Respiratory acidosis is a condition that occurs when the lungs cannot remove all of the carbon dioxide the body produces. This causes body fluids, especially the blood, to become too acidic.
Not removing enough CO2
Low pH
High pCO2
High HCO3- tries to neutralize acid
Caused by: neurological, respiratory, paralysis
3 Types: Intrapleural, intraalveolar, misc.,
Intrapleural Causes
AKA atelectasis (collapsing of alveolar sacs) Something extra in plueral space
Intraalveolar Causes
Anything which causes no gas exchange
- Drowning
- Pneumonia
- Pulmonary contusion
- Pulmonary edema- fluid in lungs
Emphysema
Lungs loose elasticity
Hardening of yellow elastic connective tissue
Increase of CO2 in blood
Obstructed Airway Causes
Aspiration
Strangulation
Mucous plug in ET tube
Medications- OPIODS- extreme resp. depressants
Asphyxiation
Deprivation of oxygen
NEVER leave pop-off valve closed
2 Main Reasons for Ventilating a Pt. on Anesthesia
- Decrease excess CO2- prevent hypercapnia
2. Prevent atelectasis- collapsing of alveolar sacs
4 Elements of Blood Gas
ph= 7.35-7.45
pCO2= 35-45 mmHg
HCO3= 18-25 mmol/L
Anion Gap= 12-24 meq/L
Metabolic Acidosis
Low pH (<7.35) Low HCO3 (bicarbonate) Caused by --> renal failure, ketoacidosis
Metabolic Alkalosis
High pH (>7.45) High HCO3 (bicarbonate) Caused by --> vomiting (decrease in HCl)
3 Functions of the Cardiovascular System
- Transportation of O2, CO2, nutrients, hormones, vitamins, waste
- Regulation of pH, fluid balance body temp.
- Defense against foreign organisms
Plasma
Fluid portion of anti-coagulated blood
Contains clotting factors, has ability to clot
Serum
Fluid portion of coagulated blood
Does not contain clotting factors
Dissolved Substances
Proteins- albumin, clotting factors, antibodies Nutrients- glucose, oxygen Electrolytes- Na+, Cl-, K+ Waste Products- BUN, bilirubin Hormones and Enzymes Cells
Electrical Conduction System of the Heart
- Sinoatrial Node (SA node)- Right atrium
- Atrial-Ventricular Node (AV node)- Septim between atria and ventricles
- Bundle of His- Septum of ventricles (interventricular septum)
- Purkinjie Fibers- Travel up right and left ventricular walls
- Both atria contract simultaneously with SA node
- Both ventricles contract simultaneously with AV node
Diastole
Relaxation of ventricles
Systole
Contraction of ventricles
Blood Flow Through the Heart
Vena Cava –> Right atrium –> Tricuspid valve –> Right ventricle –> Pulmonary valve –> Pulmonary artery –> Lungs –> Pulmonary vein –> Left atrium –> Bicuspid valve –> Left ventricle –> Aortic valve –> Aorta
Normal HR for Canines, Felines, and Equine
Canines: 60-160 bpm
Felines: 140-220 bpm
Equine: 30-40 bpm
Cardiac Output Formula
C.O= stroke volume (mls) X HR (bpm)
*C.O has a direct impact on BP
Normal Pressure Values
Systolic: 100-160 mmHg
Diastolic: 60-100 mmHg
Mean: 80-120 mmHg
How to Control BP
Regulate vessel diameter with vasoconstrictors –> increase BP
Control C.O with inotropic drugs (increase force of ventricular contraction) –> increase S.V
Regulate blood volume with IV fluids –> increase BP
*Give fluid bolus to pts. with low BP
Right Heart Failure (RHF)
Symptoms: ascites (fluid inside abd. cavity)
Left Heart Failure (LHF)
Congestive Heart Failure
*More common
Symptoms: pulmonary edema, decreased BP due to tachycardia
Treatment: O2, diuretic (draws fluid out of lungs), cardiac regulator (inotropic drugs)
Purpose of an ECG
Helps diagnose arrhythmias
Shows electrical activity of the heart
5 Leads to Attach to ECG
White: right axillary Black: left axillary Red: left inguinal Green: right inguinal Tan: sternum
5 Parts to an ECG
P wave: atrial depolarization (contraction, systole)
QRS complex: ventricular depolarization (contraction, systole)
T wave: ventricular repolarization (relaxation, diastole)_
6 Step Approach
- Rate (bradycardia, tachycardia, normal)
- R-R Interval (want to stay consistent)
- P-wave for every QRS complex
- QRS complex for every P-wave
- QRS complex normal size and shape? (tall and thin)
- T-waves normal? (no more than 25% of height of R wave)
Respiratory Sinus Arrhythmia
Common in large, deep chested breeds
Can be normal variation in dogs
HR will increase on inhalation and decrease on exhalation
Ventricular Premature Contraction (VPC)
Some ectopic force is causing the ventricle to beat prematurely
If occasional –> OK
Treatment: Lidocaine, Procainamide
Ventricular Tachycardia
More than 3 VPCs in consecutive sessions
–> significant decrease in C.O
Treatment: Lidocaine (IV), Procainamide
Ventricular Fibrillation (V-FIB)
Ventricle is not contracting in a normal fashion
Treatment: defibrillation
2nd Degree AV Block
Block in conduction between SA node and AV node
–> bradycardia
Treatment: anticholinergics (atropine sulfate) (IV)
3rd Degree AV Block
SA and AV node are not communicating
P-wave and QRS complex are not coordinated
Treatment: pace maker
Patent Ductus Arteriosus (Congenital)
*Most common defect in mammals
Opening between the pulmonary artery and the aorta in fetal circulation (should normally close after birth)
Causes machinery murmur (whoosh whoosh)
Symptoms: lethargic upon exercise, cyanotic mm
Treatment: sx, suture ductus closed (not open heart sx, trocharize thorax)
Patent Foramen Ovale (Congenital)
Opening between left and right atrium in fetal circulation (should normally close after birth)
Treatment: open heart sx, suture a patch over foramen (dacron patch)
Very expensive
Can produce hypothermic pt. (85 degrees will allow for 45 min. without damage to cardiac muscle)
Aortic Stenosis
Due to scar tissue
Causes dilation of left ventricle –> LHF
Symptoms: pulmonary edema
Treatment: dissect scar tissue (can create more scar tissue)
Pulmonic Stenosis
Causes dilation of right ventricle –> RHF
Symptoms: ascites
Treatment: dissect scar tissue
Ventricular Septal Defect (VSD)
Should never be an opening between right and left ventricle
Treatment: open heart sx- patch the foramen
A-V Insufficiency (Acquired)
Opposite of stenosis, valves hang open
Valves should be closed during systole (contraction)
Causes machine murmur
More commonly effects left side
Common Causes: dental dz, poorly performed prophylaxis
Treatment: vasodilators, sx to repair mitral valve
Heartworm Dz (Acquired)
Microfilaria live in pulmonary artery (can cause obstruction)
Blood will back up to right ventricle
Most common in southern/eastern states
Treatment: heartworm prevention meds
Vegetative Endocarditis (Acquired)
Bacterial colonies on heart valves
Caused by: dental dz
Symptoms: dyspnea, exercise intolerance, enlarged heart, coughing
Cardiomyopathy (Acquired)
- Dilated
Caused by weak muscle –> myocardial infarction (heart attack)
Symptoms: wet cough
Treatment: diuretics, cardiac regulators
2. Hypertropic Caused by overwork of the heart muscle Common in maine coon cats (genetic test) Decrease HR Treatment: Anti-adrenergics- propranol
*Geriatric animals are predisposed to both
Cardiac Tamponade (Acquired)
Due to pericardial effusion (fluid build up in pericardial sac)
Causes pressure build up in sac –> will collapse chambers of the heart, decrease C.O
Dx: auscultation, very quiet heart beat
Treatment: pericardial centesis
Atherosclerosis (Acquired)
Narrowing of vessels
More common in humans due to diet
Treatment: removal bypass
Hypovolemic Shock
AKA traumatic shock
Acute blood loss (hemorrhaging, H2O loss)
Treatment: IV fluids
Septic/Distributive Shock
Septicemia
Bacterial endotoxins
Caused by: injury to GI tract, dental dz, gram positive bacteria (release exotoxins) –> blood will get trapped by the sphincters
Treatment: IV fluids, bacteriostatic antibiotics (tetracyclines)
Anaphylactic Shock
Can be caused by injectable vaccines or antibiotics
Stimulates mast cells in resp. and GI tracts
Release histamines –> vasodilation –> sphincters close
Treatment: IV fluids, corticosteroids IV (reduce inflammation), +/- epinephrine
Neurogenic Shock
Neocortex overrides brainstem
Mildest form: syncope (fainting)
Can result from life threatening situations
Humans are prone to this
Cardiogenic Shock
Caused by myocardial infection –> heart attack
Humans are prone to this
Failure of heart to pump blood adequately
–> drastic decrease in C.O
Treatment: cardiac regulator, inotropic drugs to increase C.O
Early Shock Signs
Tachycardia (up tp 240 bpm) Bounding pulses Bright mm Fast CRT Proper mentation (alert)
Compensatory Shock Signs
Tachycardia
Pale mm
Weak pulses
Depressed mentation
Decompensatory Shock Signs
Variable HR Poor/absent pulses Prolonged CRT Pale mm Dull mentation (almost comotose)
Crystalloids
LRS, Normosol, 0.9% NaCL (PSS)
Cheaper
Colloids
Hetastarch- replacement blood product
Best option
Hypertonic Saline
7% NaCl
Pulse Sites for Equine
Transverse facial artery Facial artery (submandibular) Lateral/dorsal metatarsal artery (between hock and fetlock) *mostly anesthesia
Digital Arteries
Used to evaluate the condition of the horse’s feet
Not used to palpate pulse
Venipuncture Sites for Equine
Jugular vein
Transverse facial vein (should not be pulsating)
Medial sacral vein (“tail bleeding”, used in cattle)
