Endothelial Cells of Cerebral Blood Vessels

Epithelial Cells of the Choroid Plexus

Cells that form the outermost layer of the Arachnoid

Middle Meningeal Artery

This artery lies on the surface of the dura in the epidural space & within the grooves formed on the inside of the parietal bone

The brain constitutes 2% of the body's weight but uses 20% of the body's total resting cardiac output.

It requires approximately 750 mL of blood flow/min & can extract as much as 45% of arterial oxygen to meet normal metabolic needs.

Arterial supply to the spinal cord is segmented at best, making portions of the spinal cord that receive blood supply from two separate sources vulnerable to low flow states.

The most vulnerable of these ares are:

C2 - C3

T1 - T4

L1 - L2

Increasing wakefulness

Vigilance

Responsiveness for cortical & thalamic neurons to sensory stimuli

Spacial orientation & equilibrium with posture and muscle tone

Ensuring synchronized adjustments in movement & maintain overall balance & motor coordination

Cerebellar monitoring & adjustment of motor activity occurs simultaneously with movement, enabling significant control of fine motor functions.

Structural support

Nourishment

Protection

Astroglia (astrocyte): supplies nutrients and framework for neurons

Oligodendroglia: forms myelin sheath

Ependyma: lines ventricular system; forms the choroid plexus which produces CSF

Microglia: occurs in white matter; phagocytizes waste products from injured neurons

Particle size

Lipid solubility

Protein binding potential

Water

Oxygen

Carbon Dioxide

Glucose

apneustic center

pneumotaxic center

Although the reticular activation center is not the center of consciousness,

communication in the cerebral cortex of the RAS system is apparently necessary for consciousness to occur.

• temperature regulation
• regulation of food & water intake
• control of pituitary hormone release
• augmentation of overall autonomic nervous system output to a sympathetic or parasympathetic state

A vascular supply system unique to the brain's circulation.

When complete, the Circle of Willis is capable of supporting some degree of collateral blood flow in the case of arterial occlusion, although a sufficient arterial supply in the face of arterial obstruction is not guaranteed.

verbal speech

damage to this area results in an expressive or non-fluent aphasia

• Integration of sensory information
• Awareness of body parts
• Interpretation of touch
• Pressure
• Pain
• Self preservation
• Mood
• Emotional response

• Hearing
• Speech
• Memory

• Voluntary motor function
• Cognitive function
• Expressive language

The best possible score on the Glasgow Coma Scale (GCS) is 15 & the lowest is 3

Originally the scoring system was developed to assist in general communication concerning the severity of a neurological injury

The GCS provides data about the LOC only and never should it be considered as a complete neurological examination.

It is not a sensitive tool for evaluation of an altered sensorium, nor does it account for possible aphasia

The GCS is also a poor indicator of lateralization of neurological deterioration

(lateralization involves decreasing motor response on one side or unilateral changes in pupillary reaction)

• Central Stimulation
  • Trapezius pinch: squeeze trapezius muscle between thumb & first two fingers.  Difficult to perform on large/obese adults
• Peripheral Stimulation
  • Nail bed pressure: apply firm pressure, using object such as a pen, to nail bed

Which has a less serious prognosis:

decorticate posturing or decerebrate posturing?

Outcome studies indicate that abnormal flexion or decorticate posturing has a less serious prognosis

Onset of posturing or a change from abnormal flexion to abnormal extension (decerebrate) requires immediate physician notification.

Babinski's reflex is a significant neurologic finding because it indicates an upper motor lesion in the brain, brainstem, or spinal cord.

Babinski's reflex is a pathologic sign in any individual older than 2 YOA.

The presence of this reflex is tested by slow, deliberate stroking of the lateral half of the sole of the foot.  Sustained extensor response of the big toe is indicative of a positive Babinski's reflex.

This response is sometimes accompanied by the fanning out of the other 4 toes.

Flexor response of all the toes in response to the same stimuli is a normal finding & indicates absence of Babinski's reflex.

Refer to figure 27-3 pg. 705

Pupil diameter/size should be documented in millimeters (mm) with the use of a pupil gauge to reduce the subjectivity of description.

Most people have pupils of equal size between?

What is a normal discrepancy?

Most people have pupils of equal size between 2-5 mm

A discrepancy up to 1 mm between the two pupils is normal.

An irregularly shaped or oval pupil may be noted in patients who have undergone eye surgery.

Initial stages of CNIII compression from elevated ICP can cause the pupils to have an oval shape.

Stuporous

[BOX 27-1 PG. 702

THIS GOES OVER ALL THE CATEGORIES OF CONSCIOUSNESS]

Occurs when the extremity opposite the extremity receiving pain crosses the midline of the body in an attempt to remove the noxious stimulus from the affected limb.

(gave example of placing IV in right arm and left arm moving to try and stop you)

BOX 27-4 PG. 703

CLASSIFICATION OF ABNORMAL MOTOR FUNCTION

CNIII - Oculomotor

CNIV - Trochlear

CNVI - Abducens

In the unconscious pt assessment of the ocular function & innervation is performed by eliciting the dolls eyes reflex.

If the pt is unconscious as a result of trauma the nurse must ascertain the absence of cervical injury before performing this exam.

The nurse holds the pts eyelids open & briskly turns the head to one side while observing the eye movements and then briskly turns the head to the other side & observes.

If the eyes deviate to the opposite direction in which the head is turned the dolls eyes reflex is present, and the oculocephalic reflex arc is intact.

If the oculocephalic reflex arc is not intact the reflex is absent.[image]

The oculovestibular reflex is one of the final clinical assessments of brainstem functions, following confirmation that the tympanic membrane is intact.

The head is raised to a 30° angle, then 20-100 mL of ice water is injected into the extenal auditory canal.

In a normal response, eye movement is in the direction of the injection site.

An abnormal response is disconjugate eye movement which indicates a brainstem lesion.

No response indicates little or no brainstem functioning.

[image]

Rhythmic crescendo & decrescendo of rate and depth of respiration; includes both periods of apnea

Usually seen with bilateral deep cerebral lesions or come cerebellar lesions

TABLE 27-3 PG. 709 RESPIRATORY PATTERNS

• Decreased perfusion of the cerebral tissue
• Hypoxia
• Neurological injury

• Bradycardia
• Systolic HTN
• Widening pulse pressure

Related to pressure on the medullary area of the brainstem.

What GCS score would you give a patient who responds to noxious stimuli with extension?

What score would you give someone with no response?

2 - Extension: decerebrate posturing spontaneously or in response to noxious stimuli

1 - None: no response to noxious stimuli; flaccid

Commands should be kept simple & not involve multiple stimuli: asking a pt to stick out their tongue is a simple direct command.

Having the pt to squeeze the hands or let go of the hand may be a response of what reflex?

• Instillation of cycloplegic agents (such as atropine or scopolamine)
• Can indicate specific extreme stress

• Opioid overdose
• Lower brainstem compression
• Bilateral damage to the pons

CSF is normally clear, colorless, odorless solution that contains:

• Glucose (50-75 mg/dL)
• Protein (5-25)

DOES NOT normally contain RBC's

Involves the patients ability to remain motionless during the entire procedure.

Even swallowing interferes significantly with the imaging process.

1. Cerebral embolus caused by the catheter dislodging a segment of atherosclerotic plaque in the vessel
2. Hemorrhage or hematoma formation at the insertion site
3. Vasospasms caused by the irritation of the catheter placement
4. Thrombosis of the extremity distil to the injection site
5. Allergic or adverse reaction to the contrast medium

MRA (Magnetic Resonance Angiography)

Noninvasive visualization of the cerebrovascular system.  It uses MRI technology to evaluate cerebral blood flow & provide details about cerebral vessels.

MRA of the carotid arteries has become an established complement to preoperative ultrasound evaluation.  It helps determine the area of salvageable tissue (or penumbra) after an acute stroke & head injury

MEP's (Motor Evoked Potentials)

Assess the function integrity of descending motor pathways.

The motor cortex is stimulated via the direct high voltage electrical stimulation through the scalp or use of magnetic field to induce an electrical current within the brain.

LP (Lumbar Puncture)

• Possible brainstem herniation if the ICP is elevated
• Respiratory arrest associated with neurological deterioration

MRI (Magnetic Resonance Imaging) is lengthy & requires pt to lie motionless in a tight, enclosed space.

Mild sedation or a blindfold or both may be necessary for the claustrophobic pt.

DSA uses significantly less dye then arterial angiography.

Dye is injected into the venous or arterial system.  The pt must remain motionless during the procedure.

Complications include (same as angiography):

• cerebral embolus caused by catheter dislodging a segment of atherosclerotic plaque in the vessel
• hemorrhage or hematoma formation at the insertion site
• vasospasm of a vessel caused by irritation of the catheter placement
• thrombosis of the extremity distal to the injection site
• allergic or adverse rxn to the contrast medium, including renal impairment

• Keeping the pts head elevated 45° for 8 hours
• Monitoring neurological status
• Encouraging oral fluids

Ultrasound technology, although not an absolute measure of CBF (Cerebral Blood Flow) uses a noninvasive technique to provide information about the flow velocity of blood through carotid vessels.

Carotid duplex studies are used as routine screening procedure for intraluminal narrowing of the common & internal carotid arteries as a result of atherosclerotic plaques.

Patient/Family Education

Physical preparation

Awareness of potential complications

Questions about possible sensitivity to iodine-based dye shoud be ascertained beforehand.

Persons who are allergic to shellfish are often allergic to iodine.

What category of consciousness would you choose for this pt:

Patient is disorientated to time, place, and person with loss of contact with reality & often has auditory or visual hallucinations.

Pt is asking you the same question, but totally out of context (i.e., the pt is looking around the room asking why is the cat meowing)

Delirious

BOX 27-1 CATEGORIES OF CONSCIOUSNESS PG. 702

What category of consciousness would you choose for this pt:

Patient displays a state of drowsiness or inaction in which the pt needs an increased stimulus to be awakened.

When you call their name & you have to vigorously shake them...

Lethargic

BOX 27-1 CATEGORIES OF CONSCIOUSNESS PG. 702

What category of consciousness would you choose for this pt:

Patient responds immediately to minimal external stimuli

You go in pts room and say good morning & they respond with a good morning back to you (well acknowledge you in some way at least!)

Alert

BOX 27-1 CATEGORIES OF CONSCIOUSNESS PG. 702

What category of consciousness would you choose for this pt:

Vigorous stimulation fails to produce any voluntary neural response

Pt appears to be sleeping in the bed & you are calling their name, vigorously shaking them and pt shows no form of stimulation, except he may withdrawal their arm but that is the only form of stimulation & the only response to stimulation shown

Comatose

BOX 27-1 CATEGORIES OF CONSCIOUSNESS PG. 702

CPP (Cerebral Perfusion Pressure)

CPP = MAP - ICP

Example:

MAP = 85

ICP = 15

MAP (85) - ICP (15) = CPP (70)

Average CPP: 80-100

CPP ≤30 results in cell death

*If MAP = ICP there is NO CBF (cerebral blood flow)*

Pupillary responses

They are usually intact except in anoxic encephalopathy, barbiturate intoxication, & hyperthermia.

Oftenly used to differentiate between structural & metabolic causes of the coma

• Emergency measures to support vital functions & prevent further neurological deterioration.
• Protection of the airway & ventilatory assistance are often needed.
• Administration of thiamine (at least 100 mg), glucose, & an opioid (narcotic) antagonist is suggested when the cause of the coma is not immediately known
• Thiamine is administered before glucose because the coma produced thiamine deficiency, Wernicke's encephalopathy, can be precipitated by a glucose load
  1. Thiamine
  2. Glucose
  3. Narcotic Antagonist

Which coma usually has a better outcome:

coma caused by trauma or nontraumatic coma

Which type of coma has a better prognosis:

metabolic coma or coma caused by a structural lesion?

early arousal

(pg. 726)

Instilling saline or methylcellulose lubricating drops (and taping the eyelids in the shut position) q2h

In addition, taping a polyethylene film over the eyes, extending beyond the orbits & eyebrows creates a moisture chamber around the cornea & assists in keeping the eyes moist

Rapid restoration of cerebral blood flow with thrombolytic therapy (rtPA).

Confirmation of the diagnosis of ischemic stroke with CT must be accomplished before rtPA (Recumbant Tissue Plasminogen Activator) can be administered.

National guidelines for the management of stroke are based on results of the National Institute of Neurologic Disorders (NINDS) rtPA Stroke Study.

This study showed that rtPA administered within 3 hours of the onset of stroke is effective, safe therapy for ischemic stroke

Major symptoms that are rapidly improving or only minor stroke symptoms (NIHSS <4) are a contradiction to thrombolytic therapy.

Major surgery or serious trauma in the previous 14 days are also contraindications

NIHSS (National Institutes of Health Stroke Scale) scale ranges 0-42 BOX 28-4 PG. 732

anticoagulant (aspirin, heparin, warfarin, ticlopidine)

antithrombotic

antiplatelet

pts shouldn't receive any of these medications for at least 24 hours after treatment

Rebleeding is the occurance SAH (Subarachnoid Hemorrhage) in an unsecured aneurysm, or, less commonly, an AVM.

The incidence of rebleeding during the first 24hours after the first bleed is 4% with a 1-2% chance per day the following month.

The mortality rate associated with aneurysmal rebleeding is approximately 70%

Involves increasing the pts BP & CO with vasoactive meds & diluting the pts blood with fluid, volume & expanders.

Systolic BP is maintained between 150-160 mm Hg

The increase in volume & pressure forces blood through the vasospastic area at higher pressures

Tactile agnosia or asterionosis is a perceptual disorder in which a pt is unable to recognize by touch alone an object that has been placed in his/her hand.

This may occur even in the presence of an intact sense of touch.

Hypotension

results from peripheral vasodilation & can be compounded in an already dehydrated pt who has received large doses of an osmotic diuretic in an attempt to control ICP

Barbiturates therapy is a treatment protocol developed for management of uncontrolled HTN that has not responded to the conventional treatment previously described.

The two most commonly used drugs in barbiturate therapy are pentobarbital & thiopental.

The goal with either of these drugs is a reduction in ICP to 15-20 while a MAP of 70-80 is maintained.

High dose barbiturates increase cerebrovascular resistance & therefore decrease cerebral blood flow, resulting in a reduction of intracranial volume

• Access for CSF and drainage & sampling
• Access for the determination of volume pressure turgor
• Direct measurement of pressure
• Access for medication instillation

Transcalvarial herniation is the extrusion of cerebral tissue through the cranium in the presence of severe cerebral edema.

Transcalvarial herniation occurs through an opening exposed from a skull fracture or craniotomy site.

You have a pt that has become flaccid, have fixed dilated pupils, ICP that falls from 75 to 15.

What has this pt most likely suffered?

• Fixed dilated pupils
• Flaccidity
• Respiratory arrest
• ICP drops as the pressure is relieved by shifting the intracranial components downward

Mannitol is an osmotic diuretic & will pull swelling out of the edematous brain tissue, thereby decreasing ICP.

Lying the pt flat in the bed will impair venous drainage from the head & worsen ICP

Receptive aphasia is also known as Wernicke's aphasia.

This pt presents with impaired ability to comprehend

Also known as Broca's asphasia

Pt presents with impaired ability to physically articulate speech

This type of stroke can affect speech, cognitive functions, such as addition/subtraction.

There is usually not a change in the LOC with the left cerebral ischemic stroke

Common symptom in diagnosing a pt with SAH (Subarachnoid Hemorrhage) is a pt c/o "the worst headache I've ever had".  There is usually not a loss of consciousness & usually there is not a complaint of weakness that is necessarly present with the onset.

Main symptom is abrupt onset of a severe headaches (sometimes N/V & photophobia)

Large molecules, such as albumin & RBC's are prevented from entereing the filtrate.

The presence of large molecules in the urine is a signal that the glomerular membrane is damaged or affected by disease

The ability of the kidneys to autoregulate blood flow begins to fail when the mean arterial BP is <80 or >180.

When the mean arterial BP is decreased, the afferent arteriole dilates & the efferent arteriole constricts to maintain a higher pressure in the glomerular capillary bed & maintain the GFR

Creatinine is used as a measure of the GFR because it is a wast product produced at a fairly constant rate by the muscles.

It's freely filtered by the glomerulus & is minimally reabsorbed or secreted by the tubules.

A creatniine clearance <100 reflects a GFR of <100 mL/min and is a signal of decreased kidney function

A creatinine clearance & GFR <20 mL/min results in symptoms of kidney failure

What percentage of water content does a male, female, & infants have?

How does body fat affect fluid percentages?

Adult male pts usually have a water content of approximately 60%

Adult females has closer to 50%

Infants have a body fluid content estimated at 77%

With an increase in body fat, the body fluid percentage decreased because fat contains a smaller & less significant amount of water than muscle.

[Pg. 770 right hand side towards the bottom]

An isotonic solution has roughly the same concentration of particles as the blood plasma; cells within an isotonic solution maintain consistency & do not lose or gain fluid to their surroundings.

Colloid osmotic pressure is created primarily by the presence of plasma proteins in the intravascular space.

Plasma proteins exert a pull on water molecules & therefore produce osmotic pressure, which retains fluid within the intravascular compartment.

This force is maintained because proteins are large & cannot move or be transported across the semipermeable membrane unless the permeability of the membrane is changed by disease or other assaults on the body (i.e., burns, infections)

ADH is the major regulator of extracellular fluid volume.

ADH release results in increased fluid level reabsorption.  Thus as fluid is reabsorbed, hemodilution or over-hydration will occur

increased hematocrit

delayed skin turgor

Magnesium in the body functions as an intracellular carrier of substances that carry Na & K across the cell membrane.

A depletion of magnesium liberates K to the extracellular fluid & thereby increases renal excretion of K, resulting in hypokalemia

• Volume depletion
• Hypoperfusion
• Hypotension
• HTN
• Decreased CO (cardiac output)

The BUN/Creatinine & low urine output are secondary to the renal failure that most likely resulted that most likely results from long-term HTN

A reduction in vascular volume stimulates the release of Renin.

Renin converts to angiotensin I which converts to the powerful vasoconstrictor angiotensin II

In turn, angiotensin II stimulates the adrenal gland to secrete aldosterone which acts on the distal tubules to reabsorb Na from the tubular lumen into the circulation therefore increasing water absorption as well (where salt goes water follows...)

• Formation of urine
• BP regulation
• Regulation of acid/base balance
• Produce RBC's (by secretion of erythropoietin)

Decreased albumin levels in the vascular space result in the plasma to interstitial fluid shift, creatign peripheral edema.

A decreased albumin level can occur as a result of protein calorie malnutrition, which occurs in many critically ill pts, in whom available stores of albumin are depleted.

A drop in systolic BP of 20 mm/Hg or more

A drop in diastolic BP of 10 mm/Hg or more

or

A rise in pulse rate of more than 15 bpm from lying to sitting, or from sitting to standing indicates orthostatic hypotension

The drop in BP occurs because sufficient preload is not immediately availabe when the pt changes position.

The HR increases in an attempt to maintain CO & circulation

Percussion is performed to detect pain in the area of a kidney to determine excess accumulation of air, fluid, or solid around the kidneys.

Percussion of the kidneys also provides information about kidney location, size, & possible problems.

Differentiating ascites from distortion caused by solid bowel contents is accomplished by producing a fluid wave.

A fluid wave is elected by exerting pressure to the abdominal midline while one hand is placed on the right or left flank.

Tapping the opposite flank produces a wave in the accumulated fluid that can be felt under the hands.

Daily weight

24-hour I & O

The PAOP (Pulmonary Artery Occlusion Pressure) represents the left atrial pressure to fill the left ventricle.

When the left ventricle is full at that end fo diastole, it represents the volume of blood available for ejection.

It is also known as left ventricular preload & is measured by the PAOP.

The normal PAOP is 5-12 mm/Hg.

In fluid volume excess, the PAOP rises and in fluid volume deficit the PAOP is low.

When the serum osmolality level is increased, ADH is released from the posterior pituitary gland & stimulates increase water reabsorption in the kidney tubules.

This expands the vascular space, returns the serum osmolality level back to normal and results in more concentrated urine & an elevated urine osmolality level.

Decrease in a specific gravity reflects the inability of the kidneys to excrete the usual load into the urine.

A low specific gravity reflects the inability of the kidneys to concentrate urine

BUN & Creatinine

(hemoglobin & hematocrit may or may not be elevated & blood glucose levels should remani constant with the opposing action of insulin & glucagon)

2 x Na(mmol/L) + BUN /3 (mg/dL) + Glucose/18 (mg/dL)

Example:

Na = 145

BUN = 18

Glucose = 108

(2 x 145) + (18 ÷ 3) + (108 ÷ 18) =

290 + 6 + 6 = 302

Serum Osmolality = 302

Although the choice of fluid & the amount used are based on the pts general condition & that pts ability to tolerate interventions,

Saline or solute loading in the prevention mode of treating acute tubular necrosis (ATN) has been proven to expedite reovery.

Irritation of the GI tract from metabolic waste accumulation in relation is expected.

A stress ulcer prophylactic is usually prescribed & usually stool, NG drainage & emesis are routinely tested for occult blood.

A patent fistula has a thrill when palpated gently with the fingers

and has a bruit if ascultated with a stethoscope

(feel the thrill, hear the bruit)

As a critical care nurse we will frequently assess the quality of blood flow through the fistula.  You need to assess for both a thrill & bruit.

The extremity should be pink & warm to touch.

NO BP measurements, IV infusion, or laboratory phlebotomy procedures are performed on the arm with the fistula

To remove fluid, a positive hydrostatic pressure is applied to the blood & a negative hydrostatic pressure is applied tot he dialysis bag.

The two forces together cause the transmembrane pressure pull & squeeze the excess fluid from the blood.

The difference between the two values represents the transmembrane pressure & results in fluid extraction which is known as ultra filtration from the vascular space.

Most electrolytes like K become increasingly elevated in ARF

Ca levels are reduced

In each case, these conditions often produce life threatening cardiac dysrhythmias (if the levels are too low they can also produce life threatening cardiac dysrhythmias)

The oliguric or anuric phase, the second phase of ATN, lasts 5-8 days in the nonoliguric pt and 10-16 days in the oliguric pt.

The accumulation of necrotic cellular debris in the tubular space blocks the flow or urine & causes damage to the tubular wall & basement membranes.

Excess electrolytes, fluid, & toxins by the use of a hemodialyzer.

Although hemodialysis is efficient in removing solutes it DOES NOT remove ALL the metabolite.

Furthermore, levels of electrolytes, toxins, & fluids increase between treatments, necessitating hemodialysis on a regular basis.  Normally a pt will dialyze in a hemodialysis clinic 3 x per week

(normally either: MWF or TRS)

air embolism

decrease in flow pressure

electrolyte imbalances

blood leaks

access failure

clotted hemofilter

CVVH is used for large volume removal & hemodynamicly unstable pts.

Treatment of choice for the pt who is too hemodynamicaly unstable to do hemodialysis.

• Urea
• Creatinine
• Uric acid
• Na
• K
• Ca
• Drugs not bound by proteins

Blood loss or the response to the blood products & medications.

Then use the order vasopressor support & decrease the net ultra filter to Ø (zero)

Provides information about electrolyte changes that may occur in and may need to be corrected with a pt in ARF.

Activate a PT & INR are important in determining bleeding & clotting time to prevent hemorrhage & clots

Renal Failure

(you have an increase in metabolic waste products during renal failure & those metabolic waste products would be your creatinine)

When you have a pt whose hemodynamic parameters are consistent with hypovolemia you would treat with fluid resuscitation of 0.9% NS.

Dopamine would not be your drug of choice because it is a alpha andrenergic drug & could further decrease renal flow.

If you have a pt that appears to be in acute anuric renal failure that would mean that the K that was not eliminated from the body but was simply shifted intracellular, soon the K will return to the blood stream.

The Kayexalate will help permanently remove it from the body.

Continuous Renal Replacement Therapy uses what to push water across a dialysis filter & drag solutes with it? 

(This is considered as convection.)

Recovery may last 1-2 years: renal function returns to normal; urine production increases

Oliguric or Anuric lasts 5-16 days: An accumulation of cellular debris causes damage to the tubular walls; BUN increases

Onset lasts from hours to days: GFR is decreased & irreversible damage can be avoided

Diuretic phase lasts 7-14 days: GFR increases, edema & scarring of tubules is present

Shock is a complex pathophysiological process that often results in MODS (Multiple Organ Dysfunction Syndrome) & death.

All types of shock eventually result in ineffective tissue perfusion & the development of acute circulatory failure

Hypovolemic shock occurs from inadequate fluid volume in the intravascular space.

The lack of inadequate circulating volume leads to decreased tissue perfusion & initiation of the general shock response.

Hypovolemic shock is the most commonly occurring form of shock.

Measures to facilitate the administration of volume replacement include insertion of large-bore peripheral IV cath, rapid administration of prescribed fluids, & positioning the client with the legs elevated, trunk flat and head/shoulders above the chest

Cardiogenic shock is the result of failure of the heart to effectively pump blood forward.

It can occur with dysfunction of the right or left venticle (or both).

The lack of adequate pumping function leads to decreased tissue perfusion & circulatory failure.

Assessment of the hemodynamic parameters of the pt in cardiogenic shock reveals decreased CO with a CO <2.2 L/min

With anaphylactic reactions that are IgE mediated, the next time the antigen enters the body the preformed IgE antibody reacts with it and a second immune response occurs.

This reaction triggers the release of biochemical mediators from the mast cells & basophils and initiates the cascade of events that precipitates anaphylactic shock.

increased CO

decreased systemic vascular resistance

The syndrome encompassing severe sepsis & septic shock is a complex systemic response that is initiated when a microorganism enters the body & stimulates the inflammatory/immune system.

Shedded protein fragments & the release of toxins and other substances from the microorganism activate the plasma enzyme cascades (complement, kinin/kallikrein), coagulation, & fibrinolytic factors) as well as platelets, neutrophils, monocytes, & macrophages.

To reverse the pathophysiologic responses, control the infection, & promote metabolic support.

This approach includes supporting the cardiovascular system & enhancing tissue perfusion, identifying & treating the infection, limiting systemic inflammatory response, restoring metabolic balance, & initiating nutritional therapy.

• flat neck veins
• decreased LOC
• weak & thready peripheral pulses
• narrow pulse pressure

• compensatory - tachycardia, vasoconstriction, & hypoglycemia
• progressive - ventilation failure, ARDS, DIC, ATN
• initial - decreased CO & tissue perfusion
• refractory - MODS (clinical manifestations would be death)

fluid resuscitation to maintain central venous pressure at 8 mL or greater

administer activated protein C

achieve central venous saturation of 70% or more

• temp >38°C or <36°C [>100.4°F or <96.8°F]
• HR >90 bpm
• RR >20 or PaCO₂ <32 mm/Hg
• WBC >12,000 or <4,000 or >10% immature (band) forms

Tumor Necrosis Factor A (TNF) is a polypeptide that is released from macrophages & lymphocytes in response to endotoxin, tissue injury, viral agents & interleukins.

When present in excessive amounts TNF causes?

• hypoperfusion & shock like state
• translocation of normal GI bacteria into systemic circulation
• colonization of oral pharynx with pathogenic organism

• thrombocytopenia
• prolonged clot times
• decrease platelet counts & levels of clot factors (particularly factor VII, fibrinogen, & fibrin)
• increased levels of breakdown products fibrinogen fibrin degradation product & d-dimer

Autocatabolism

Autocatabolism manifests as a severe decrease in lean body mass, severe weight loss, anergy, & increased CO & Vo₂ resulting from profound alterations in carbohydrate, protein, & fat metabolism.

Normally a pt with SIRS requires 20-25 calories/kg/day for adequate nutritional support.

(1 kg = 2.2 lbs)

• begins with lungs (most commonly affected organ)
• then to liver
• gut
• kidneys
• late components are:
  • cardiac
  • bone marrow (at times)

hyperacute rejection occurs within hours after transplantation & results in immediate graft failure.

The primary mechanism triggering this response is activation of humoral-mediated rejection.

Such an immediate response by the immune system is caused by the presence of preformed reactive antibodies as a consequence of previous exposure to antigens.

Presensitization can be the result of previous blood transfusions, multiple pregnancies, or previous organ transplantation.

because of synergistic effect

they have lower drug dose, decrease risk of side effects, infection, & malignancy

Initial treatments of triple drug regimen consists of high-dose corticosteroids with a calcineurin inhibitor such as cyclosporine or tacrolimus in addition to mycophenolate mofetil, sirolimus, & occassionally azathioprine.

These triple-drug regimens are designed to prevent rejection while reducing the toxicity of the individual drugs.

A 2nd P-Wave

2nd p-wave is generated by the native SA node that has been left in the atrial cuff

because this impulse doesn't cross the suture line, it is capable of conducting only through the remnant of the native recipient atria.

this impulse is not seen in hearts transplanted with use of the bicaval technique because the native right atrium & its SA node are removed.

FFP (fresh frozen plasma)

plasma contains most clotting factors & indicative for liver dysfunction.  administration of plasma may decrease risk of bleeding tamponade.

A major but rare complication of biopsy is ventricular perforation, which results in cardiac tamponade.  This emergency situation may require open heart surgical repair.

Pneumothorax may result from perforation of the visceral pleura during cannulation of the jugular vein; its clinical manifestations are a sudden onset of sharp pain in the affected side & dyspnea.

Pt weaned from vent support as soon as possible.  Longer period of intubation the higher the risk of pneumonia.

After extubation pt encouraged to cough, deep breath, & get out of bed.

Pulmonary function studies usually not started for a couple weeks after transplantation.

Hypovolemia can lead to?

(with organ transplant)

compromised blood flow to kidneys

ATN (acute tubular necrosis)

possible graft failure

blood glucose levels

pancreatic biopsy is rarely done

Cyclosporine can cause what? 

What form does it come in?

Can I switch out forms it comes in?

What are benefits?

Can cause HTN

Comes in capsule & liquid form

They are not interchangable

Immune system has some ability to work & doesn't affect bone marrow

Cyclosporine

This inhibits T-Cells generation without totally impairing the body's ability to fight infection

• Liver - HTN, renal insufficiency
• Heart - absence of chest pain, silent infarction
• Lungs - obliterative broncholitis

renal disease

age

peripheral vascular disease

lack of interest

failure to approve protocols

delays in termination of life support

• Head: 9% total (4.5% anterior/posterior)
• Trunk: each side=18%
• Arm: each arm=4.5%
• Leg: each leg=9%
• Groin: 1%

You have a pt that has sustained partial & full-thickness burns.

One half of her arm, her entire left leg, & her perineum.  What percentage of her body is burned?

arm = 4.5%

left leg = 18%

perineum = 1%

total = 23.5%

a light to bright red moderate appearance

these wounds may appear wet & weeping, may contain bullae, & are extremely painful and sensitive to air currents

the microvessels that profuse this area are injured and the permeability is increased resulting in leakage of large amounts of plasma into the interstitium.

this fluid in turn lifts off the thin damaged epidermis causing blister formation

despite the loss of the entire basal layer of the epidermis, a burn of this depth will heal in 7-21 days

Restriction of chest wall expansion & decreased compliance.

Decreased compliance requires higher ventilator pressures to provide the pt with adequate tidal volumes.

According to the Parkland formula,

half (50%)of the calculated amount of fluid is administered to the pt in the first 8 hours after injury.

25% is given in the second 8 hours.

25% is given in the third 8 hours.

TABLE 41-1 PG. 1024

Plasma colloid osmotic pressure is decreased as a result of?

(in reg to burns)

What is the half life of carbon monoxide at the following O₂ levels:

Room air/21% O₂

40% O₂

100% O₂

Hyperbaric Oxygen Chamber

Room Air/21% O_{2 =} 4 hours

40% O₂ = 2 hours

100% O₂ = 40-60 min

Hyperbaric Oxygen Chamber = 30 min

(3x the atmospheric pressure)

[currently the use of hyperbaric O₂ is of controversial benefit in the care of a burn pt]

As healthcare providers it is always our goal & duty to prevent spreading infections & cross contamination between pts.  What are some interventions to implemetn for this?

(burn pts)

• Proper hand washing between each pt
• Protective isolation equipment as required by each pt
• Cleaning shared equipment with bacterialcidal agent between uses

Although the polyurethane film dressings possess many of the properties of an ideal skin substitute, fluid can collect under the dressing in large quantities.

When fluid collects it often leaks & decreases the adherence of the dressing.

The fluid can be removed with a needle & syringe (use caution, the needle can punture the dressing.  if punctured it must be patched with a small piece of polyurethane film)

Initially after a burn injury how are narcotics administered & when can they be given orally?

(burn pts)

Initially after a burn injury narcotics are administered intravenously in small doses & titrated to affect

the constant background pain may be addressed with the use of a PCA device

once hemodynamic stability has occurred and GI function has returned, oral narcotics can be useful.

splints may be taken off for 2 hours every shift to allow burn care & ROM exercises

mild contractures may be kept in a splint for 4 hours & out of splints for 4 hours to promote exercise & mobility

• consideration of motivation
• willingness to participate in care
• ability to understand & perform the necessary procedures
• potential aversions to wound care or dressing changes
• reliability of transportation

Wound surface is usually red with patchy white areas that blanche with pressure

These burns are not usually characterized by blister formation

Pain mngmt in burn injuries must be addressed early & frequently and reassessed to determine the adequacy of interventions.

IV opiates such as morphine sulfate are indicated & titrated to affect

• pulses
• skin color
• capillary refill
• sensation

• a urinary output of 0.5-1 mL/kg/hr
• HR <120 bpm
• BP in normal to high ranges
• central venous pressure <12 cm or PAOP <18
• clear lung sounds
• clear sensorium
• absence of intestinal events (such as nausea & paralytic ileus)

loss of function setting in after 12-24 hrs

numbness & paresthesia may occur only 30 min before loss of pulses

Escharotomy may become necessary to allow the underlying tissue to expand

in deeper wounds, fasciotomy, which involves incision inot the fascia, may be necessary

Can result in a profound alteration in acid-base balance & rhabdomyolysis resulting in myoglobinuria which poses a serious threat to renal function.

Myoglobin is a normal constituent of muscle.

With extensive muscle destruction it is released into the circulatory system & filtered by the kidneys.

It can be highly toxic & can lead to intrinsic renal failure.

Daily cleansing & inspection of the wound & unburned skin are performed to assess for signs of healing & local infection.

Generally this therapy is performed once or twice daily.

Pain management & measures to reduce hypothermia are used.

Pts should receive adequate premedication with analgesics, narcotics, and/or other sedatives.

Hypothermia

Heat is lost through the open burn wound by means of evaporation & radiation

• Zone of coagulation is usually the site of greatest heat transfer & where irreversible skin death occurs.  Site of the most severe damage.
• Zone of Stasis is characterized by impaired circulation that can lead to cessation of blood flow.  Area is potentially salvageable.
• Zone of hyperaemia where there is vasodilation & increased blood flow but minimal cell involvement.  early spontaneous recovery can occur in this area.