Vet tech prep power pages: surgical nursing review

The kidney is resoponsible for

regulating water and electrolyte balance in the body

the kidney maintains

acid-base homeostasis

the kidney aids in retaining

protein and glucose in the body

the kidney excretes

waste and toxins

the kidney plays a role in many

endocrine functions by secreting hormones

renal refers to the

kidneys

acid (kidney)

a substance that releases hydrogen ions in solution (pH <7).

base (kidney)

a substance that accepts hydrogen ions in solution (pH >7).

Nephron

functional unit of the kidney

renin

hormone secreted by the kidney;

-mediates extracellular volume and arterial vasoconstriction (regulates blood pressure) via the renin-angiotensin system

Aldosterone stimulates

active sodium reabsorption

antidiuretic hormone (ADH) stimulates

passive water reabsorption

the kidney is made up of

nephrons

The nephron is the

functional unit of the kidney

The nephron is made up of

the glomerulus

the glomerulus is surrounded by

Bowman's capsule and its tubule

The tubule is sectioned into the

proximal tubule, the medullary loop of henle, and the distal tubule which empties into the collecting duct.

Filtration in the kidneys happens through the

glomerular capillaries.

the filtration inside the glomerular capillaries is driven by

hydrostatic pressure as a direct result of arterial pressure.

Glomerular Filtration Rate (GFR)

the rate at which filtration through the glomerular capillaries occurs

The loop of henle is resposible for

concentrating the urine

what is resorbed at the loop of henle

sodium and chloride

The final urine concentration is dependent upon the

amount of antidiuretic hormone secreted by the pituitary gland

The proximal tubule resorbs

all glucose and amino acids, and most bicarbonate, phosphate, and water.

Renin increases the production of

Angiotensin II

Renin is released in response to

intravascular volume drops (dehydration, blood loss)

renin release causes then causes aldosterone release from

the adrenal cortex

renin release also causes increased release of

ADH from the posterior pituitary causing increased thirst, and constriction of the efferent arteriole to maintain GFR. In fluid overload, the opposite occurs.

Aldosterone causes

sodium and water resorption in the distal tubule and collecting duct

in the distal tubule and collecting duct

sodium is exchanged for potassium and hydrogen

what is released when sodium is low in the blood

aldosterone

examples of sodium loss

Vomiting or loss of gastric acids

sodium loss leads to

alkalosis

Antidiuretic hormone makes the

distal tube and collecting duct more permeable to water, which increases urine concentration

When antidiuretic hormone (ADH) is present

the urine is concentrated

When antidiuretic hormone (ADH)is not present

Nerve impulses from the hypothalamus stimulate

the pituitary to make ADH when osmotic blood pressure rises.

Vitamin D (calcitriol) is produced by the

to help promote calcium absorption from the intestine

the kidney also produces erythropoietin which

stimulates production of red blood cells.

Kidney values on a blood panel

BUN and creatinine

Amylase is excreted through

the kidneys

if renal function is impaired, amylase

rises

important factors on kidney function besides BUN/creatine is

UA and electrolyte values

How many cranial nerves are there?

12

cranial nerve diagram

CN 1

Olfactory nerve

CN 1- olfactory

Mediates the sense of smell, observed when the pet sniffs around its environment

CN 2

Optic

CN 2- Optic

Carries visual signals from retina to occipital lobe of brain, observed as the pet tracks an object with its eyes. It also causes pupil constriction.

The Menace response

is the waving of the hand at the dog's eye to see if it blinks (this nerve provides the vision; the blink is due to cranial nerve VII)

CN III

oculomotor nerve

CN III - Oculomotor Nerve

• Provides motor to most of the extraocular muscles (dorsal, ventral, and medial rectus) and for pupil constriction o Observing pupillary constriction in PLR

CN IV (4)

trochlear nerve

CN IV (4)- Trochlear Nerve

Provides motor function to the dorsal oblique extraocular muscle and rolls globe medially

CN V (5)

Trigeminal Nerve - Maxillary, Mandibular, and Ophthalmic Branches

CN V (5)- Trigeminal Nerve - Maxillary, Mandibular, and Ophthalmic Branches

• Provides motor to muscles of mastication (chewing muscles) and sensory to eyelids, cornea, tongue, nasal mucosa and mouth.

CN VI (6)

abducens nerve

CN VI (6)- Abducens Nerve

• Provides motor function to the lateral rectus extraocular muscle and retractor bulb

CN VI (6)- Abducens Nerve is tested by

touching the globe and observing for retraction (also tests V for sensory) Responsible for physiologic nystagmus when turning head (also involves III, IV, and VIII)

CN VII (7) facial nerve

• Provides motor to muscles of facial expression (eyelids,ears,lips) and sensory to medial pinna(ear flap). Also taste to rostral tongue

CN VII (7)

facial nerve

CN VII (7) facial nerve helps with

tear production (schirmer tear test)

CN VII (7) facial nerve- Palpebral response

-motor for the blink reflex when touching medial canthus (also tests V for sensory)

can observe for facial paralysis by

CN VII (7) facial nerve

symptoms: deviation of nose to one side or droopy lips

CN VIII (8)

vestibulocochlear nerve

CN VIII (8) -vestibulocochlear nerve

Sensory for hearing and head position

A head tilt or nystagmus may suggest dysfunction of

CN VIII (8)- Vestibulocochlear Nerve (vestibular disease or inner ear disease)

CN IX (9)

Glossopharyngeal nerve

CN IX (9)- Glossopharyngeal Nerve

•Innervates the pharynx for swallowing (with X).

-Also innervates some salivary glands and provides taste innervation from caudal tongue

examine the CN IX (9) - Glossopharyngeal Nerve by

eliciting a gag reflex and observing for dysphagia (difficulty swallowing)

CN X (10)

vagus nerve

CN X (10) - Vagus Nerve

•Innervates the larynx, esophagus, and pharynx. Also provides parasympathetic innervation to the heart and viscera

CN X (10) - Vagus Nerve is tested by

a gag reflex along with CN IX (9)

CN XI (11)

spinal accessory nerve

CN XI (11) spinal accessory nerve

•Innervates cranial cervical (neck) muscles

CN XII (12)

hypoglossal nerve

CN XII (12) hypoglossal nerve

• Motor to the tongue (causes tongue movement)

GDV

Gastric Dilatation Volvulus (Bloat)

GDV is a condition most prevalent in

dogs

GDV mortality rate

15-30%

Is GDV an emergency?

yes patients are typically in critical condition with shock at presentation, requiring aggressive resuscitation and immediate supportive care and monitoring

definitive GDV treatment includes

surgical decompression and derotation of the stomach followed by gastropexy to prevent recurrence.

GDV is most common in

large breed, deep chested dogs. Great dane is most common breed.

When antidiuretic hormone (ADH)is not present

the tubule is not very permeable to water so the urine is dilute

GDV is when the

-stomach rotates counterclockwise when viewing from cranial to caudal in dorsal recumbency

-Also can be stated that stomach rotates clockwise when viewed caudal to cranial

GDV can result in

-venous compression, congestion, and local compromise of perfusion to the stomach, resulting in necrosis

-tearing of short gastric vessels connecting the stomach and spleen

GDV leads to hypovolemic shock because

Air accumulates in stomach, eventually impeding venous return to the heart via the vena cava and resulting in hypovolemic shock

GDV can lead to

-global tissue ischemia and systemic inflammatory response

○ Inflammatory mediators and myocardial ischemia can lead to arrhythmias

GDV happens more in

-large to giant breeds

-deep chested dogs

-Great Dane, German Shepherd,

Rottweiler, Irish Wolfhound, etc

great danes have what percent likelihood of developing GDV

37%

Other predisposing factors for GDV

○ Related to a dog that had a GDV

○ Anxious dogs

○ Very fast eaters

Clinical signs of GDV

● Restless/nervous pacing

● Painful ● Non-productive retching/vomiting

● Abdominal distension

● Increased respiratory rate

● Signs consistent with shock/cardiovascular collapse

○ Tachycardia, weak pulses, pale mucous membranes, prolonged CRT

○ Depressed to comatose mentation

We diagnose GDV by

-ECG- arrythmias common, VPC most likely

-blood gas- Metabolic acidosis (lactic acidosis) +/- respiratory compensation:, May have hypercapnia from gastric distention and impaired ventilation

-radiographs

treatment of GDV includes first stabilizing the patient:

● Place two large-bore cephalic catheters (avoid saphenous since caudal venous return is poor)

● Shock dose crystalloid fluid therapy (80-90 ml/kg in fractions until resuscitation achieved) ○ Patient's large size often requires use of pressure bags for rapid administration of fluids

● Monitor blood pressure and ECG ● Lactate levels may provide some insight as to prognosis

Treatment of GDV includes decompressing the stomach:

1. Orogastric tube

a. Pros: more effective emptying

b. Cons: requires heavy sedation, tube might not pass, possible esophageal trauma/rupture

2. Trocarization

a. Pros: more rapid intervention, does not require sedation

b. Cons: limited decompression, risk of lacerating gastric wall, puncturing spleen

c. Trocarize at point of maximum tympany, can't be sure if spleen is on the left or right

Treatment of GDV inlcludes: Surgey:

● Goal is to fully decompress and reposition stomach, evaluate viability of stomach and resect any necrotic tissue. Also assess spleen, determine if splenectomy is indicated (rarely necessary)

. ● Perform gastropexy to prevent recurrence. ○ Incisional, circumcostal, belt-loop, incorporating, tube.

survival rate of GDV

Reported survival 75-90% with surgery and post-operative care

Negative prognosis indicators of GDV

○ Lactate > 6 mmol/L

○ Need for gastric resection/splenectomy

○ Long onset of signs to time of presentation (5 or 6 hours)

○ Recumbency at presentation

If a patient has GDV and a gastropexy is performed, the recurrence of GDV is

less than 4%

If a patient has GDV and a gastropexy is NOT performed, the recurrence of GDV is

recurrence is 50%