Term
| • Know the normal heart rate of small dogs |
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Definition
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Term
| • Know the normal heart rate of large dogs. |
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Definition
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Term
| • Know the normal heart rate of cats. |
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Definition
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Term
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Definition
- results in decreased cardiac output and subsequent poor perfusion
- often develops in cats in shock (<120 beats/min) and can be assoc w/ imminent cardiac arrest
- unusual finding in a critically ill pt, can result from electrolyte imbalances (hyperkalemia), neurologic dzs (increased intracranial pressure), conduction disturbances (AV block, sick sinus syndrome) or OD of anes or analgesia
- ECG indicated for full assessment |
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Term
|
Definition
- dogs >180 bpm, cats > 220 bpm
- body’s response to decreased blood volume, pain, anxiety, and hypoxiemia
- increasing HR will temp increase cardiac output and O2 delivery
- some limitation to response – when HR too fast, diastolic filling is compromised and stroke vol suffers
- sinus tachycardia often results from circulatory shock or pain
- tachycardia that is irregular or assoc w/ pulse deficits usually indicates an arrhythmia and an ECG is indicated |
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Term
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Definition
- pale or white = anemia or vasoconstrictive shock
- red = suggest vasodilation as seen in systemic inflammatory states and hyperthermia
- cyanotic = indicate a normal PCV (cyanosis will not be clinically evident w/o adequate hemoglobin) but severe hypoxia
- yellow = indicates increased serum bilirubin (from hepatic dz or hemolysis)
- brown = can be seen w/ methomoglobinemia
- petechiation or bleeding should be noted
- thrombocytopenia is an early finding in disseminated intravascular coagulation
- petichiae and bruising are clinical signs of platelet deficiency or dysfunction |
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Term
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Definition
- subject to interpretation, even recently deceased pt may have a normal CRT
- used w/ pulse quality, resp effort, HR, and gum color, CRT can help assess blood vol and peripheral perfusion, and give an insight into causes of causes of a pt’s shock
- normal CRT 1 – 2 sec = consistent w/ normal blood vol and perfusion
- CRT >2 sec is a subjective sign of poor perfusion or peripheral vasoconstriction
- peripheral vasoconstriction is an approp response to low circulating blood vol and reduced oxygen delivery to vital tissues
- pts w/ hypovolemic and cardiogenic shock should be expected to have peripheral vasoconstriction
- also commonly assoc w/ cool extremities
- CRT < 1 sec indicative of hyperdynamic state and vasodilation ( as are bright red mm)
- hyperdynamic states can be assoc w/ systemic inflammation, heat stroke, distributive shock and hyperthermia |
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Term
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Definition
- can be a sign of venous overload or R sided congestive heart failure
- palpation of jugular vein may demonstrate distention (may be easier to clip sm patch of hair over the lateral saphenous vein)
- w/ pt in lat recum, if the lateral saphenous vein appears distended (as if being held off), slowly raise the rear leg above the level of the heart.
- If vein remains distended, the pt likely has an elevated central venous pressure and volume overload or dzs causing right sided congestive heart failure (DCM, tricuspid insufficiency, pericardial effusion) should be considered.
- pt w/ pale mm from vasoconstriction in response to hypovolemia would not be expected to have venous distention
- cardiogenic shock is more likely to cause pale mm and increased venous distention |
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Term
| • At what body temperature should warming measures be discontinued? |
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Definition
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Term
| • How often should patients be turned to help prevent lung consolidation and pneumonia? |
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Definition
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Term
| • Know the nutritional needs of postoperative patients. |
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Definition
| - at least 30 kcal/kg q 24h |
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Term
| • Know the consequences of cellular hypoxia in shock and critical patients. (Very important!) |
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Definition
- resuscitation and stabilization of critical pts require rapid reestablishment of adequate oxygen delivery to the tissues
- if cellular hypoxia of the GI tract extends beyond 1 hr, death from organ dysfunction and sepsis from GI bacterial translocation and endotoxin absorption across the gut may occur a day to several days later
- speed of resuscitation also critical in saving the life of a pet w/ multiple injuries
- shock and tissue hypoxia must be rapidly reversed in the critical pt |
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Term
| • Know which drugs with significant hemodynamic effects should, and should not, be used in critical patients. |
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Definition
- analgesic and sedative drugs w/ significant hemodynamic effects (such as acepromazine and medetomidine) should not be used in the critical pt
- opiods and benzodiazepines are the most frequently used sedative and analgesic drugs for the critically ill or injured pt
- NSAIDS should also be avoided until hemodynamic stability, GI fxn, and renal fxn have been evaluated |
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Term
| Primary survey of a critical patient – ABCDE approach |
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Definition
Airway
Breathing
Circulation
Disability
External assessment |
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Term
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Definition
- A = Airway
assessment of airway, includes early, aggressive, nonconfining O2 supplementation by directing a oxygen source at nose/mouth (flow-by O2) via a face mask or clear plastic hood
if resp fxn is compromised or absent, bag-valve-mask ventilation immed while prepping to intubate
preox of pat w/ bag-valve-mask before attempting to intubation may reduce incidence of cardiopulmonary arrest
orotracheal intubation indicated if airway obstructed or if pt has absent gag reflex
if cannot be placed due to obstruction, emerg tracheotomy or cricothyroidotomy indicated |
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Term
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Definition
B = breathing
once airway established, observe breathing efforts
if none visible or weak intubate if not done already and initiate manual positive pressure ventilation
if unconscious the head shouldn’t be elevated, intubate in lateral or dorsal recumbency
if breathing spontaneously, adequacy of oxygenation and ventilation best assessed by careful visualization and auscultation
assess oxygenation by pulse ox and arterial blood gas measurement |
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Term
|
Definition
- C = Circulation
major visible hemorrhage – apply pressure manually/compression dressings
in some cases direct exposure/temp vascular occlusion and subsequent ligation or repair of the bleeding vessels is needed
assess tissue perfusion – level of consciousness, pulse strength, mm color, CRT, jugular vein distention, HR
when palpable pulses and audible HR absent, cardiac arrest should be assumed and CPR started
if intubation and manual ventilation not already started, should be initiated immed in addition to chest compressions and approp resuscitative drug admin
obtundation, pale mm, slow CRT, poor jugular vein distention are all indicative of poor perfusion or shock
arterial BP and jugular vein distention/speed of filling/emptying indicate global perfusion and rapidly determined point-of-care serial lactate, PvO2, and base excess values aid in further assessment of tissue perfusion
venous partial pressure of O2 (PvO2) is effective means of assessing perfusion effectiveness. PvO2 <35 mm Hg indication of hyperperfusion
Doppler blood flow monitoring, w/ the probe placed on the palmar arterial arch (or even the surface of the eye in the arrested or near arrested unconscious pt) is very effective in assessing circulatory fxn
3 main causes of shock = hypovolemia, vasodilation, cardiac failure, pts may suffer from more than one of these
most shock states in trauma pts result from blood loss, w/ secondary causes assoc w/ plasma-fluid loss, third space loss w/in edema assoc tissues, and pain over time
critically ill pts may be hypovolemic due to severe dehydration or third space fluid losses (esp into GI tract)
vasodilation typically from severe systemic inflammatory response, w/ or w/o sepsis
anaphylaxis and ischemic-reperfusion injury can also cause generalized vasodilation
vasodilatory shock may cause hyperemic mm and bounding pulses but most pts w/ vasodilatory shock have concurrent hypovolemia and will demonstrate signs more consistent w/ hypovolemic shock b4 adequate fluid resuscitation
primary cardiac dz is most common cause of cardiogenic shock
also secure IV access while ABC performed, opening in skin or minicutdown makes this easier
immed fluid resuscitation vital for all shock pts OTHER THAN those w/ suspected cardiac failure
in most cases, fluid resus aims to restore normal CV patamenters
in cases of active internal hemorrhage, a less aggressive fluid resus such as “hypotensive resus” may be considered |
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Term
|
Definition
- D = Disability
level of consciousness and ability to move and feel pain in all 4 limbs assessed
- AVPU
A = alert
V = responsive to verbal stimulation
P = responsive to painful stimulation
U = unresponsive to painful stimulation
- most important emergency triage drug to use in virtually all head or spinal cord emergent/critical conditions is supplemental O2 |
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Term
| - E = External assessment |
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Definition
- E = External assessment
particularly relevant to the acute trauma pt
evaluate entire animal for bleeding (incl orifices), lacerations, punctures, abrasions, contusions, significant swelling, crepitus, pain on palapation, obvious hernias, open fractures, angulations or deformitites
examine umbilical region for periumbilical ecchymosis (Cullen sign) which may indicate hemorrhage in the peritoneum or retro peritoneum |
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Term
| Secondary survey of the critical pt |
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Definition
- after primary survey complete and appropriate emergency therapy started
- full PE
- measurement of arterial BP
- assessment of jugular vein distention and relaxation time
- eval of emergency blood work results
ideally should include:
hemoglobin levels or packed red cell volume
total protein
BG
lytes
arterial and venous blood gases
lactate measurements
- assess O2 w/ pulse ox or arterial blood gas analysis
- Arterial partial pressure of O2 (PaO2) <80 mm Hg (pulse ox sat < 95%) indicates hypoxemia
- PaO2 of <60 mm Hg (SpO2 <90%) indicates severe hypoxemia
- if severe hypoxemia persists despite O2 therapy and management of primary dz processes (ex: evacuation of pleural space dz), mechanical ventilation is indicated
- ventilator ability best evaluated by measurement of the partial pressure of CO2 in arterial or venous blood (PCO2)
- PCO2 levels < 45 mmHg indicate hypoventilation
- PCO2 levels > 60 – 70 mm Hg despite tx of the primary dz process is an indication for mechanical ventilation |
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Term
| • Know the arterial partial pressures of oxygen that would result in hypoxemia and severe hypoxemia |
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Definition
- Arterial partial pressure of O2 (PaO2) <80 mm Hg (pulse ox sat < 95%) indicates hypoxemia
- PaO2 of <60 mm Hg (SpO2 <90%) indicates severe hypoxemia
- if severe hypoxemia persists despite O2 therapy and management of primary dz processes (ex: evacuation of pleural space dz), mechanical ventilation is indicated |
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Term
| • What PCO2 levels would indicate hypoventilation and show an indication for mechanical ventilation? |
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Definition
- PCO2 levels < 45 mmHg indicate hypoventilation
- PCO2 levels > 60 – 70 mm Hg despite tx of the primary dz process is an indication for mechanical ventilation |
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Term
| • What measures can be take to insure that an endotracheal tube is properly placed or is still in the trachea? |
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Definition
- direct visualization of tube entering larynx
- palpation of neck to ensure tube is not felt w/in esophagus
- proper chest wall movement during ventilation |
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Term
| • What is the recommended respiratory rate during CPR? |
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Definition
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Term
| • Ventilation during CPR should not exceed how many cm H2O pressure? |
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Definition
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Term
| • What is the proper number of chest compressions that should be performed during CPR? |
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Definition
| - 100 – 120 compressions/min, pt in lateral recum |
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Term
| common causes of cardiac arrest in patients |
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Definition
- hypotension (secondary to hypovolemia, sepsis, or drug admin)
- hypoxemia (secondary to hypoventilation or lung dz)
- metabolic derangements (eg, severe metabolic acidosis)
- electrolyte abnormalities (eg hyperkalemia)
primary myocardial dz, a common cause of cardiac arrest in humans, is uncommon in vet pts |
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Term
| 2 subsets of pts that suffer cardiopulmonary arrest |
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Definition
| those with reversible causes of arrest and those w/ dz processes that cannot be reversed |
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Term
| Know the advantages, and disadvantages, of following the ABC mnemonic for basic life support |
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Definition
Pros-
- Establishing an airway
- Ensuring adequate ventilation
- Generating blood flow via external chest compression or internal cardiac compression
- All must be performed quickly and properly to maximize the chance for recovery
Cons
- Used to determine the order of intervention in basic life support, often results in a delay in the initiation of chest compressions until the pt is intubated |
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Term
| • What is the proper number of chest compressions that should be performed and guidelines during CPR? |
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Definition
100 – 120 compressions/min, pt in lateral recum
- Chest compressed to a depth of 25 – 33% of the thoracic diameter w/ a 50:50 ratio of compression to relaxation
- In small pts (<15kg), the compressions are performed directly over the heart to maximize the effectiveness of the cardiac pump mechanism
- Very sm pts (puppies/cats), the entire thorax may be circled and chest compressed w/ operator’s thumbs
- Larger pts (>15kg), compressions should be performed over the widest part of the thorax
- This results in the greatest change in intrathoracic pressure and maximizes flow via the thoracic pump mechanism
- Properly performed, may generate ~20% of normal cardiac output but may be diminished by other factors
- Very lg dogs (>50 kg) hard to be effective, internal cardiac compressions may result in sig higher myocardial perfusion pressure |
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Term
| Interposed abdo compressions |
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Definition
- Increase the effectiveness of external chest compressions, resulting in increased venous return to the thorax in diastole and thus increasing forward flow
- Adjunct to standard CPR
- Pts w/ no known abdo trauma, hemoperitonium or recent abdo sx
- Abdo compressed during relaxation phase of chest compressions, requiring coordination between the thoracic and abdo compressors |
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Term
| • Know when fevers become a threat to the life of patients. |
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Definition
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Term
| • Know the various causes of a true fever. |
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Definition
- A true fever is the body’s normal response to infxn and injury and is part of the acute phase response. Controlled by thermoregulatory center in hypothalamus
- May be initiated by variety of substances incl infectious agents or their products, immune complexes, tissue inflammation or necrosis, and several pharmacologic agents. Collectively called exogenous pyrogens
- In response to stimulation by an exogenous pyrogen, proteins (cytokines) released from cells of the immune system trigger the febrile response
- Macrophages are the primary immune cells involved, although T & B lymphocytes and other leukocytes may play significant roles
- The proteins produced are called endogenous pyrogens or fever-producing cytokines.
- Although interleukin-1, interleukin-6 and tumor necrosis factor-alpha are considered the most important fever-producing cytokines, at least 11 cytokines can start a febrile response |
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Term
| • Know the appropriate, and the inappropriate methods, of cooling patients that are hyperthermic. |
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Definition
O2 and IV Isotonic Fluid Therapy
Surface cooling techniques
- Clip fur if indicated
- Tepid water to skin or whole body (manually or via bath)
- Fan
- Ice packs over areas w/ lg vessels (neck, axilla, inguinal region)
- Combo of above
Internal cooling tech
- Rectal admin of cool isotonic fluids
- Gastric lavage
- Open body cavity
- Peritoneal dialysis
Extracorporeal techniques
Antipyretic drugs
- Antiprostaglandins
- Dantrolene
- Dipyrone
- Aminopyrine
- COX-2 inhibitors (COX = Cyclooxygenase-2)
- Glucocorticoids
- Addt’l NSAIDS |
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Term
| Blood pressure and hypotension |
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Definition
- The force that the flow of blood puts on vessel walls
- MAP equates to overall pressure throughout the cardiac cycle
- Most of the cardiac cycle is spent in diastole, therefore most of the mean blood pressure is affected by the diastolic BP
- BP = CO x SVR (Cardiac output x systemic vascular resistance)
- (CO is the product of HR and stroke vol (CO= HR SV))
- (SV is the amt of blood ejected w/ each heartbeat and is affected by the preload, contractility and afterload
- (vascular resistance refers to the effects of vascular tone and blood viscosity on flow through a blood vessel.)
- Resistance to blood flow through a vessel increases as the blood becomes more viscous and as the vessel becomes more constricted
- Thus hypotension is typically the result of a decrease in the HR, SV, the SVR of the entire arterial vasculature, or, more commonly, a combination |
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Term
| • What effect would increased sympathetic noradrenergic innervation of cardiac muscle have? |
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Definition
| - Mediates increases in HR (chronotropic effect) and force of contraction (inotropic effect |
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Term
| • Know the normal, low value, and high values of the MAP |
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Definition
- Normal dogs/cats 60-100 mm Hg
- Low <60 mmHg
- High >100 mmHg |
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Term
| • Know the clinical signs of systemic hypotension. |
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Definition
- Depend on underlying cause, duration and severity
- Tachycardia
- Abnormal pulse quality (weak or bounding)
- Pale mm
- Slow capillary refill time
- Mental dullness
- Hypothermia
- Cold extremities
- Decreased urine output
- Weakness
- Mm in dogs w/ sepsis or systemic inflammatory response syndrome (SIRS) often injected rather than pale
- Cats w/ hypotension due to sepsis or SIRS often have bradycardia and rarely have injected mm |
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Term
| • Know the appropriate supportive therapies for systemic hypotension. |
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Definition
- Most important to treat underlying cause if possible
- Very important to differentiate between primary cardiogenic causes and other causes of hypotension
Primary cardiogenic causes
- Primary cardiogenic causes such as severe arrhythmias and DCM do not respond to fluid therapy, often worsen following fluids and may result in severe pulmonary edema
- Cardiogenic causes differentiated based on PE, thoracic rads, ECG, echocardiography
- Specific therapy may incl positive inotropic meds, diuretics and even vasodilatory agents
Primary cardiogenic dz excluded
- General tx (beyond tx specific dz) aggressive IV fluids
- Goal of fluid therapy is to increase preload, stroke volume, and cardiac output and to correct specific deficits (ex: anemia) if present
If fluid goals met and hypotension persists
- Cause is either secondary cardiogenic or vasodilatory
- Tx of secondary cardiogenic hypotension gen requires inotropic support with b-adrenergic agonists
- Conversely, a-agonists or vasopressin are used to manage vasodilatory hypotension
- Choice to use either is a clinical decision based on whether poor cardiac output or low systemic vascular resistanceis predom responsible for hypotension
- Many dzs that cause vasodilation can cause decreased cardiac contractility and vice versa
- Therefore, the decision to manage w/ an inotrope or vasopressor is often empiric
- Consider the possible benefits/consequences
- Positive inotrope to animal w/ vasodilatory shock, consequences may incl arrhythmias and/or vasodilation
- Vasopressor when decreased cardiac contractility present will worsen cardiac output by increasing afterload
- Clinical judgment and response to empirical therapy are often used to guide vasopressor therapy |
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Term
| • What are the parameters that define oliguria in patients? |
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Definition
- Less than 0.27 ml/kg/hr to less than 1 - 2 ml/kg/hr
- Normal output for dogs and cats is 1-2 ml/kg/hr |
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Term
| • What are the causes of pre-renal oliguria? |
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Definition
- Hypovolemia
- Dehydration
- Blood loss
- Third space losses
- Decreased cardiac output
- CHF
- Cardiac tamponade
- Sepsis
- Vasodilation
- Cirrhosis
- Nephrotic syndrome
- Vasodilatory drugs |
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Term
| • What are the causes of post-renal oliguria? |
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Definition
- Urethral obstruction
- Urinary tract rupture |
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Term
| • Causes of renal oliguria |
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Definition
- Acute tubular necrosis
- Ischemia
- Nephrotoxicity
- Chronic renal failure (end stage) |
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Term
| • Which drugs are used to treat patients with oliguria? |
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Definition
- Loop diuretics such as furosemide (logic is that increasing the vol of ultrafiltrate in the tubular lumen will help to flush out tubular debris that might otherwise contribute to further damage. Also, since furosemide inhibits the Na+-K+-2Cl- pump of the ascending limb of the loop of Henle, it was thought that the subsequent decrease in renal tubular energy requirements would also be of benefit. many studies done on usefulness of furosemide, but none have shown clear therapeutic benefit)
- The osmotic diuretic mannitol – also increase the vol of ultrfiltrate which may be of benefit in flushing debris from the tubular lumen. Also has free-radical scavenging capabilities,
- Production of )2 free-radical spp has been implicated in the progression of acute tubular necrosis so scavenging of thesde agents would theoretically be of benefit – no human/vet trials have shown this to be the case.
- Mannitol use w/ caution – can result in aggressive expansion of the vascular col and vol overload if not excreted
- Final tx – dopamine – catecholamine that exerts dopaminergic as well as a-adrenergic and b-adrenergic effects
- In both human/vet med, low dose admin (<5ug/kg/min) has been advocated to increase renal blood flow and urine output, w/ the goal of either preventing or reversing oliguria
- Unfortunately, the theoretical benefits of dop not recog clinically, human lit recommendation is against use of dop at a “renal dosage”. No clinical trials for vet pts w/ renal failure
- Addtl therapies under investigation for the tx of acute renal failure incl fenoldopam (a selective DA-1 receptor agonist), calcium channel blockers (diltiazem) and atrial natriuretic peptide – at this time insufficient evidence to recom use in vet med
- Animals that are oliguric despite therapy may req dialysis as a lifesaving measure |
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Term
| • What are the common states of consciousness? |
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Definition
- Normal – normal demeanor and interaction w/ environment (must rely on client’s knowledge of the pet’s behavior as well as initial neurologic eval
- Obtunded – a state of decreased responsiveness or alertness, graded as mild, moderate or severe. Lethargy is similar, reflecting decreased level of consciousness w/ listlessness and drowsiness. Terms commonly used in humans such as confusion, delirium and dementia are difficult to extrapolate to vet med
- Stupor or semicoma – pt responds only to vigorous or painful stimuli
- Coma – pt does not respond consciously to any stimuli. Segmental spinal reflexes will be present (in the absence of addtl lesions) and poss exaggerated, and cranial nerve refleses may be present, depending on the location of the lesion causing the coma |
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Term
| • Which part of the brain is responsible for the integration of sensory information from the entire body, the planning of motor activity, and the appropriate responses to this information, emotion, and memory? |
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Definition
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Term
| • Which part of the brain activates the cerebral cortex and maintains consciousness? |
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Definition
- The ascending reticular activating system (RAS) or reticular formation – a network of anatomically and physiologically distinct nuclei in the brain stem that fxn to “activate” the cerebral cortex and maintain consciousness
- Numerous nuclei in the RAS have projections to the cerebrum but those in the midbrain, rostral pons, and thalamus are the most important for maintaining consciousness |
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Term
| • Which common metabolic diseases may cause altered mentation? |
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Definition
- Hypoxia (anemia, pulmonary dz, methemoglobinemia)
- Ischemia (cardiac dz, postarrest, hyperviscosity, systemic embolic dz)
- Hypoglycemia
- Hepatic dz (hepatic encephalopathy)
- Renal failure (uremic encephalopathy)
- Endocrine dysfxn (hyper or hypo fxn)
_ pituitary (apoplexy)
_ thyroid
_adrenal (hypoadrenocorticism, pheochromocytoma)
_pancreas (DM, esp hyperosmolar)
- Sepsis
- Hyperbilirubinemia (kernicterus)
- Hyper or hypothermia
- Pain
- CNS dzs
_ continuous seizure activity
_postictal state
_diffuse meningitis or encephalitis
- Electrolyte or acid-base abnormalities
_sodium or water
_magnesium
_calcium
_acidosis (metabolic or respiratory)
_alkalosis (metabolic or respiratory) |
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Term
| • Know the common drugs that may cause altered mentation |
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Definition
- Anticonvulsants (barbituates, bromides)
- Benzodiazepines
- Opiates
- Anesthetic drugs
- Atropine
- Abx (penicillin, cephalosporins, quinolones, aminoglycosides, metronidazole)
- Steroids
- Histamine-2 receptor blockers
- Cardiac glycosides (digitalis)
- Antihypertensives (hydralazine, ACE inhibitors)
- Illicit substances (cannabis, cocaine, amphetamines) |
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Term
| • Know the most life-threatening causes for a decline in mentation for patients in an ICU. |
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Definition
- Increased intracranial pressure and herniation of brain structures
- Infarction or hemorrhage secondary to the underlying brain lesions is also possible |
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Term
| • Know the normal values for oxygen and hypoxemia in patients. |
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Definition
| - Hypoxemia occurs when the partial pressure of oxygen in the arterial blood (PaO2) is less than 80 mm Hg (sea level) |
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Term
| • Know the 5 primary causes of a reduced PaO2 in arterial blood. |
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Definition
- Decreased partial pressure of inspired o2 (PiO2)
- Hypoventilation
- Ventilation-perfusion (Va/Q ) mismatch
- Shunt
- Diffusion impairment |
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Term
| • Decreased partial pressure of inspired oxygen (PiO2)/decreased inspired oxygen |
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Definition
- as occurs at high altitudes , causes hypoxemia
- in this case, not a pathological prob
- avg barometric pressure (BP) at sea level is 760 mm Hg
- PiO2 determined by total BP – vapor pressure of water (VPH2O) at body temp (47 mmHg at 37 C) times the fraction of of inspired oxygen (FiO2). The FiO2 of unsupplemented air (room air) is approx. 21%
- PiO2 (sea level) = FiO2 (BP – VPH2O)
- = 0.21 (760-47)
- = 150 mm Hg
- PiO2 (5000 ft) = FiO2 (BP – VPH2O)
- = 0.21 (640 – 47)
- = 124 mm Hg
- Animals at higher altitudes will compensate by increasing alveolar ventilation – result is normal oxygenation w/ a lower partial pressure of carbon dioxide (PCO2) or mild hyperventilation |
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Term
|
Definition
- Results in less fresh gas reaching the alveoli (decreasing alveolar ventilation)
- By bringing less fresh air to the alveoli to dilute waste gases, hypoventilation causes a rise in blood PCO2;
- An elevated PCO2 is, by definition, hypoventilation
- Because the gas exchange surfaces in the lungs are normal, hypoxemia from hypovent is corrected by increasing the FiO2 (fraction of inspired oxygen) w/ supplemental oxygen
- Linear relationship between PCO2 and PaO2 – as PCO2 rises (hypovent), PaO2 falls. A function of the resp exchange ratio, this inverse linear relationship is nearly 1:1. For every torr (mm Hg) the PCO2 goes up, PaO2 will down ~ 1 torr
- Arterial PO2 can fall to extremely low levels only if severe hypoventilation occurs in the pt breathing room air
- Another important metabolic consequence of extreme hypovent is resp acidosis |
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Term
| • Ventilation-perfusion (Va/Q) mismatch |
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Definition
- Occurs when ventilation and blood flow are not closely matched in gas exchange units, resulting in inefficient gas exchange
- Normally ventilation and perfusion are closely matched so that blood is directed to well-ventilated alveoli
- Parts of lung with more ventilation than perfusion (High Va/Q) = increased PaO2
- Parts w/ less ventilation than perfusion (low Va/Q) = lower PaO2
- Extreme of low Va/Q – parts not ventilated at all but perfused, the functional result is a shunt
- Most common cause of low Va/Q – pulmonary conditions that cause incomplete alveolar collapse (pneumonia, pulmonary edema, atelectasis)
- Hypoxic pulmonary vasoconstriction – compensatory reflex vasoconstriction of pulmonary vessels in response to low alveolar oxygen tension, reduces perfusion to poorly ventilated alveoli, improving Va/Q matching and optimizing gas exchange |
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Term
|
Definition
- Occurs when venous blood bypasses gas exchange areas of the lung and mixes w/ oxygenated arterial blood
- Venous admixture can result from either cardiac or pulmonary shunt
- Ex: cardiac shunt – Eisenmenger’s ventricular septal defect, tetralogy of Fallot
- Pulmonary shunt can result from – pulmonary masses, complete lung atelectasis, orpulmonary dz causing regions of alveolar collapse and/or obstruction
- Shunt is the most important cause of clinically significant hypoxemia, because not very responsive to oxygen therapy (because the oxygen conent of the blood perfusing the alveoli can be increased only minimally w/ the increased FiO2and is insufficient to compensate for the very low O2 content of the blood perfusing the ventilated alveoli |
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Term
|
Definition
| - Implies that normal equilibration between alveolar gas and pulmonary capillary blood does not occur |
|
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Term
| • Know what happens when venous blood bypasses the gas exchange areas of the lung and mixes with oxygenated arterial blood. |
|
Definition
Shunt
- Occurs when venous blood bypasses gas exchange areas of the lung and mixes w/ oxygenated arterial blood
- Venous admixture can result from either cardiac or pulmonary shunt
- Ex: cardiac shunt – Eisenmenger’s ventricular septal defect, tetralogy of Fallot
- Pulmonary shunt can result from – pulmonary masses, complete lung atelectasis, orpulmonary dz causing regions of alveolar collapse and/or obstruction
- Shunt is the most important cause of clinically significant hypoxemia, because not very responsive to oxygen therapy (because the oxygen conent of the blood perfusing the alveoli can be increased only minimally w/ the increased FiO2and is insufficient to compensate for the very low O2 content of the blood perfusing the ventilated alveoli
- |
|
|
Term
| • What is the normal FiO2 of unsupplemented room air? |
|
Definition
|
|
Term
|
Definition
- Inadequate cellular energy production and most commonly occurs secondary to poor tissue perfusion
from low or unevenly distributed blood flow. This leads to a critical decrease in oxygen delivery (DO2) compared to oxygen consumption (VO2) in the tissues
- Key predictor of outcome in shock pts is the magnitude of the oxygen deficit |
|
|
Term
| • Know the causes of hypovolemic shock and how it is treated |
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Definition
- Hypovolemic shock – a decrease in circulating blood vol
- Hemorrhage
- Severe dehydration
- trauma |
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Term
| • Know the causes of cardiogenic shock and how it is treated |
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Definition
- Cardiogenic shock – a decrease in forward flow from the heart
- CHF
- Cardiac arrhythmia
- Cardiac tamponade
- Drug overdose (anesthetics, beta-blockers, calcium channel blockers, etc) |
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Term
| • Know the basic diagnostic tests that should be initially completed as a part of the initial survey for all shock patients in order to assess the extent of organ injury and identify the etiology of the shock state. |
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Definition
For all shock pts
- Venous or arterial blood gas w/ lactate measurement
- CBC
- Blood chemistry panel
- Coag panel
- Blood typing
- Urine analysis
May be indicated once stabilized
- Thoracic/abdo rads
- Abdo u/s
- ECG |
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Term
| • Signs of a well-perfused pt |
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Definition
- Central venous pressure brtween 5 and 10 cm H2O (2 – 5 in cats)
- Urine prod of at least 1 ml/kg/hr
- MAP between 70 – 120 mm Hg
- Normal body temp, HR, heart rhythm and RR
- Moist, pink mm with CRT <2s
Addt’l monitoring may be beneficial
- Measurement of blood lactate
- Indices of systemic oxygenation transport
- Mixed venous oxygen saturation |
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Term
| • What are the most suitable treatments for the initial treatment of shock? |
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Definition
- Mainstay for all forms of shock except cardiogenic:
- Rapid vascular access essential but may be difficult (due to poor vascular filling and a collapsed cardiovascular state – since speed vital, use short, lg bore catheters in a central or peripheral vein – may need to do cut-down or IO cath)
- Admin of lg volumes of isotonic crystalloid fluids, enough to restore effective circulating vol and tissue profusion
- Studies don’t show clear benefit of one type of fluid over another, however, failure to administer an adequate vol of fluids may contribute significantly to mortality |
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Term
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Definition
| severe inflammatory response syndrome – a widespread response to an insult that is infectious or noninfectious in origin |
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Term
| • Know the properties and consequences of severe inflammatory response syndrome (SIRS). |
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Definition
- Most commonly assoc w/ sepsis but other dz states known to cause widespread release of endogenous mediators (trauma, burns, major sx, pancreatitis, etc)
- Can progress to mult organ failure, shock, and death due to the magnitude of the inflammatory response alone (and in absence of infxn)
- SIRS describes a clinical state rather than a dz entity
- Proposed dx criteria – 2 out of 4 signs
1. Hypo or hyperthermia
2. Leukocytosis or leukopenia
3. Tachycardia
4. tachypnea |
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Term
| • What can severe systemic inflammation often lead to in patients |
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Definition
- Vascular hyporesponsiveness, increased endothelial permeability, and a hypercoagulable state
- Can progress to mult organ failure, shock, and death due to the magnitude of the inflammatory response alone (and in absence of infxn) |
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Term
| • What are the treatments for SIRS? |
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Definition
| - Supportive care aimed at preserving organ fxn and tx of underlying dz |
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Term
| • What can trigger systemic inflammation? |
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Definition
- May be triggered by products of both gram-positive and gram-negative bacteria
- Inflammatory response is designed to protect the host
- Excessive activation of inflammation however, may contribute to mult organ failure and death |
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Term
| • What are the common causes of SIRS? |
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Definition
| - Most commonly assoc w/ sepsis but other dz states known to cause widespread release of endogenous mediators (trauma, burns, major sx, pancreatitis, etc) |
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Term
| • How are pathogens in hospitals most commonly spread? |
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Definition
- Primarily via the hands of personnel
- Reservoirs of pathogens incl humans, animals, fomites, air currents, water and food sources, insects and rodents |
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Term
| • What are the most effective methods to prevent the spread of pathogens in veterinary hospitals? |
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Definition
| - Frequent hand washing and use of gloves when handling pts |
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Term
| • What are the guidelines for the prevention and control of nosocomial infections in veterinary hospitals? |
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Definition
- Simple, 3 main approaches
1. Methods needed to prevent cross-contamination and to control potential sources of pathogenic microorganisms that can be transmitted from pt to pt or from hospital personnel to pt
2. Guidelines are needed to direct the appropriate use of prophylactic, empiric and therapeutic antimicrobial use
3. Strategies to limit the emergence or spread of MDR pathogens should be developed and targeted against organisms known to be prevalent in individual institutions |
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Term
| • What are the timelines that are now generally accepted to define if infections are considered to be nosocomial? |
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Definition
- If they develop at least 48 hrs after hosp admission w/o proven prior incubation
- If they occur up to 3 days of d/c or w/in 30d of a sx procedure |
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Term
| • What are the risk factors for nosocomial infection in the intensive care unit (ICU)? |
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Definition
- Significant risk factor is trauma
- Understaffing and overcrowding in the ICU |
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Term
| • What are the indications for a central line IV catheter? |
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Definition
- Lg vol crystalloid or collaid infusion
- Continuous drug infusion
- Repeated blood sample collection
- Infusion of parenteral nutrition or other hyperosmolar substances
- Central venous pressure measurement |
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Term
| • What are the contraindications for placing a central line IV catheter? |
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Definition
- Coagulopathies
Thrombocytopenia
Thrombocytopathia
Vit k antagonist rodenticide
- Hypercoagulable states
Hyperadrenocorticism
Disseminated intravascular coagulation (DIC)
Protein losing enteropathy
Protein losing neuropathy |
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Term
| • Which vessels should central venous catheters not be placed into? |
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Definition
| - Not placed in the jugular vein in cases of increased intraocular or intracranial pressure or thrombosis of one jugular vein |
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Term
| • What are the indications, and contraindications, for a vascular cutdown to facilitate the placement of an IV catheter? |
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Definition
Indications
- Catheterization of vessel in pts w/ extreme hypotension, peripheral vasoconstriction, or obesity
- Infusion of crystalloid or colloid fluids
- Infusion of blood products
- Infusion of drugs
- Obtain blood samples
Contraindications
- Abrasion, burn or pyoderma over catheter site
- Direct percutaneous catheterization is possible |
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Term
| • Which scalpel blade is recommended for use in performing an IV cutdown? |
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Definition
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Term
| • Which suture material is recommended for use in performing an IV cutdown? |
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Definition
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Term
| • What specific types of catheters are indicated when performing IV cutdowns? |
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Definition
| - 14 – 18 g venocath or over the needle peripheral catheter |
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Term
| • How long should catheters placed by cutdown in emergency situations be left in place? |
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Definition
| - Only until pt’s vol and BP have been normalized |
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Term
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Definition
the body’s inability to produce energy (ATP) required to sustain physiologic functions.
- This occurs because of a lack of oxygen delivery to the tissues, preventing efficient energy production through aerobic metabolism.
- the body’s response to inadequate tissue perfusion
- Can be result of accident or sx
- Signs of shock
Tachycardia
Prolonged crt
Weak pulse
Tachypnea
Hypothermia
Weakness
Depression
Dilation of pupils
- Hypovolemic
- Distributive (vasculogenic)
- Cardiogenic
- Obstructive |
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Term
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Definition
Tachycardia
Prolonged crt
Weak pulse
Tachypnea
Hypothermia
Weakness
Depression
Dilation of pupils |
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Term
| • Know the various causes of shock. |
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Definition
| - circulatory failure (hypovolemic, cardiogenic, distributive, obstructive) and any cause for inadequate energy production (hypoxemic) |
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Term
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Definition
| - circulatory failure (hypovolemic, cardiogenic, distributive, obstructive) and any cause for inadequate energy production (hypoxemic) |
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Term
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Definition
decrease in circulating blood vol
Causes:
hemorrhage,
severe dehydration,
trauma |
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Term
| - Distributive (vasculogenic)- |
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Definition
loss of systemic vascular resistance
Causes:
Sepsis
Obstruction (hw dz, saddle thrombosis)
anaphylaxis |
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Term
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Definition
– decrease in forward flow from the heart
CHF
Cardiac arrhythmia
Cardiac tamponade
Drug overdose (anesthetics, B-blockers, calcium channel blockers, etc) |
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Term
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Definition
– a decrease in O2 content in arterial blood
Anemia
Severe pulmonary dz
Carbon monoxide toxicity
methemoglobinemia |
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Term
| risk factors for nosocomial infxn in ICU |
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Definition
severity of underlying illness
prolonged length of stay
mechanical ventilation
indwelling devices |
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Term
| what is common among nosocomial pathogens? |
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Definition
| Multiple antibiotic resistance |
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Term
| What is an emerging dz in dogs/cats? |
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Definition
| - MRSA (methicillin-resistant Staphylococcus aureus) |
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