NMS Flashcards
Total body water
65% Intracellular
35% Extracellular- 25% Interstitial, 10% Intravascular
2/3 rule
Total body water comprises approximately 2/3 of body weight; of this, 2/3 is intracellular, and one third extracellular. Of the extracellular, 2/3 is interstitial, and 1/3 is intravascular.
Blood volume
Approx. 7% of body weight
Body water excreted
- urine- minimum = 0.5 mL/kg/hr
2. insensible loss (sweat, respiration, stool) = 600-900 mL/24 hr
Fluid requirement
First 10 kg = 4 cc/kg/hr
Second 10 kg = 2 cc/kg/hr
1 cc/kg/hr for every kg above
1/2 normal Saline (0.5% NaCl)
77 mEq/L Na+
77 mEq/L Cl-
Osmolarity = 154 mOsm/L
Normal Saline (0.9% NaCl)
154 mEq/L Na+
154 mEq/L Cl-
Osmolarity = 308 mOsm/L
Hypertonic Saline (3.0% NaCl)
513 mEq/L Na+
513 mEq/L Cl-
Osmolarity = 1027 mOsm/L
Lactated Ringer’s
130 mEq/L Na+ 4 mEq/L K+ 2.7 mEq/L Ca++ 98 mEq/L Cl- 28 mEq/L Lactate
Osmolarity = 525 mOsm/L
Plasmalyte
140 mEq/L Na+ 5 mEq/L K+ 3 mEq/L Mg++ 98 mEq/L Cl- 27 mEq/L Acetate 23 mEq/L Gluconate
Osmolarity = 294 mOsm/L
Signs of acute volume loss
tachycardia
hypotension
decreased urine output
Signs of gradual volume loss
loss of skin turgor
thirst
alterations in body temperature
changes in mental status
Signs of acute hypervolemia
acute shortness of breath
tachycardia
complications- acute CHF
Signs of chronic hypervolemia
peripheral edema
pulmonary edema
hyponatremia
serum Na+ < 130 mEq/L
Hyperosmolar hyponatremia
Dilutional
Causes: hyperglycemia, mannitol infusion, other osmotic particles present
Tx: correct hyperglycemia or other source
Normo-osmolar hyponatremia
Pseudohyponatremia
Causes: hyperglycemia, hyperlipidemia, hyperproteinemia
Tx: none required
Hypo-osmolar hyponatremia
True hyponatremia
Hypovolemic
Hypervolemic
Euvolemic
Hypovolemic hypo-osmolar hyponatremia
most common
total body sodium low
hypovolemia = ADH secretion, decreased free water excretion
Increased intake of free water from thirst or infusion of hypotonic solution
Dx: Urine osmolarity HIGH, Na LOW
Tx: isotonic fluid infusion, Na+ replacement if deficit is severe
Hypervolemic hypo-osmolar hyponatremia
total body sodium high
low cardiac output (less blood to kidneys, free water not excreted)
hypoalbuminemic (ex: cirrhosis) or other edematous state salt (Renin-angiotensin) and free water (ADH) cannot be excreted
Dx: Urine osmolarity HIGH, Na LOW
Tx: treat underlying medical condition, NaCl and free water restriction
Euvolemic hypo-osmolar hyponatremia
syndrome of inappropriate antidiuretic hormone (SIADH)
can be stimulated by stress response to trauma and surgery.
free water retained
Dx: Urine osmolarity HIGH, urine Na HIGH
Tx: free water restriction
Acute hyponatremia symptoms
acute cerebral edema
seizures
coma
Chronic hyponatremia symptoms
usually well tolerated
confusion/decreased mental status
irritability
decreased deep tendon reflexes
Hypernatremia
serum Na+ > 150 mEq/L
Sxs: volume depletion (tachy, hypotension)
dehydration (dry mucous membranes, decreased skin turgor)
lethargy
confusion
coma (water shift into intracellular in CNS)
Hypovolemia hypernatremia
volume deficit, more free water lost than Na+
Tx: calculate free water deficit
replace half within 8 hrs
second half over 16 hrs
Hypervolemia hypernatremia
iatrogenic infusion of too much sodium
rare
Tx: decrease Na+ infusion
free water infusion
diuretics
Free water deficit
= 0.6 x BW in kg x (pNA/140 - 1)
Hypokalemia
serum K+ < 3.5 mEq/L
Severe < 3.0 mEq/L or less
Sxs: ileus, weakness, respiratory failure, cardiac dysrhythmias
ECG changes in hypokalemia
seen when K+ < 3.0 mEq/L
T-wave flattening T-wave inversion depressed ST segments U wave development prolonged QT interval ventricular tachycardia
Causes of hypokalemia
renal- diuretics, vomiting, renal tubular acidosis
extrarenal- diarrhea, burns
intracellular shift- insulin, alkalotic state
medical disease- hyperaldosteronism, cushing syndrome
Treatment of hypokalemia
every 10 mEq of K+ should increase serum concentration by 0.1 mEq/L
Hyperkalemia
serum K+ > 6 mEq/L
Sxs: diarrhea, cramping, nervousness, weakness, flaccid paralysis, cardiac dysrhythmias
ECG changes in hyperkalemia
peaked T waves
widened QRS
ventricular fibrillation
Causes of hyperkalemia
Renal failure with inappropriate consumption/admin of K+
Extracellular shift- rhabdomyolysis, massive tissue necrosis, metabolic acidosis, hyperglycemia
Medical disease-Addison’s disease
Treatment of hyperkalemia
Acutely- IV Ca++, stablizes cardiac myocyte membrane to prevent dysrhythmias; glucose/insulin to shift K+ intracellularly; Bicarbonate to shift K+ intracellulary
Removal- ion-exchange resin (K-exylate) binds K+ in colon; Lasix only if kidneys can excrete; Dialysis
Respiratory acidosis
decreased ventilation relative to CO2 production, increased CO2 concentration
Causes: most common- decreased alveolar ventilation (respiratory depression, CNS disorder, physical), increased CO2 production (excess enteral carbs)
Tx: increase alveolar ventilation
Metabolic acidosis
loss of HCO3-, accumulation of strong anions, accumulation of weak acids
Causes: weak acid (anion gap; renal failure, lactic acidosis, DKA, toxins), strong anion (no gap; hyperchloremic acidosis), loss of bicarb (no gap; excess renal excretion, diarrhea)
Tx: underlying metabolic condition
bicarb only if pH < 7.2
Respiratory alkalosis
increase in alveolar ventilation with decrease in CO2 levels
Causes: anxiety, pain, shock, sepsis, toxins, CNS dysfunction, over ventilation
Tx: decrease ventilation, most self-limited
Metabolic alkalosis
pH over 7.45 and HCO3- > 26 mEq/L
causes: vomiting, diarrhea (loss of gastric contents), drugs that limit renal excretion of HCO3- (steroids, diuretics)
Primary hemostasis
Platelet adherence- glycoprotein Ib and vWF
Platelet activation- produce thromboxane A2 (vasoconstrict); Glycoprotein IIb/IIIa expressed for platelet-platelet adhesion (fibrinogen needed)
Extrinsic pathway
Tissue Factor (TF) binds Factor VII -> VIIa acivates Factor X -> Xa converts prothrombin -> thrombin (Va cofactor) -> fibrinogen -> fibrin
XIIIa mediates cross linking of fibrin
Intrinsic pathway
Factor XIIa activates XI -> XIa activates IX -> IXa activates X -> Xa converts prothrombin -> thrombin (Va cofactor) ->fibrinogen -> fibrin
XIIIa mediates cross linking of fibrin
Protein C and S
degrade factors V and VIII
Antithrombin III
inhibits thrombin-Xa complexes
Fibrinolysis
t-PA and urokinase-type plasminogen activator (uPA) convert plasminogen -> plasmin which cleaves fibrin
Prothrombin time (PT)
measures extrinsic cascade
measurement of vitamin K-dependent coag factors (II, VII, X)
used to monitor warfarin therapy
Activated partial thromboplastin time (aPTT)
measures intrinsic cascade
used to monitor pts on IV unfractionated heparin
Hemophilia A
Factor VIII deficiency
Hemophilia B
Factor IX deficiency
von Willibrand disease
most common congenital coagulopathy (1-2%)
vWF deficiency, treated with intranasal/IV DDVAVP
Clean wound
incision made under sterile conditions, nontraumatic procedure, does not enter bowel, tracheobronchial tree, genitourinary system, or oropharynx
should be closed primarily, infection rate less than 2%
Clean-contaminated wound
bowel, tracheobronchial tree, genitourinary system, or oropharynx was entered under sterile conditions. No evidence of active infection
should be closed primarily, infx rate 3-4%
Contaminated wound
major contamination of wound during procedure (ex: stool from colon), fresh traumatic wounds
should be left open, infx rate 7-10%
Dirty and infected wounds
established infection present before procedure (ex: appendiceal abscess)
should be left open, infx rate 30-40%
Normal wound healing phases
- Coagulation phase
- Inflammatory phase ~ 1 wk
a. cellular- PMN (24-48 hr) and macrophages remove necrotic tissue and debris; epithelial bridging
b. vascular- angiogenesis
c. mediators - Proliferative phase- fibroblasts form collagen, wound strength increases, wound contraction, 3 wks
- Wound remodeling- scar formation
Primary closure
skin edges approximated shortly after wound incurred
Secondary intention
wounds with risk or current infection left open, heal by epitheliazation and wound contraction
Delayed primary closure
heavily contaminated wounds, left open 3-5 days, then primarily closed
Skin grafts
graft contains epidermis and portion of dermis, provide epithelial coverage for healing
Flaps
Rotation flap- retains normal blood supply, rotated to fill in a defect
Free flap- removed from normal blood supply, moved to another area, vasuclature reanastomosed (ex: toe to hand to form thumb)
Fick equation
to determine caloric requirements
cardiac output x arterial-venous oxygen content difference = oxygen consumption
Systemic vascular resistance (SVR)
SVR = [(MAP - CVP)/CO] x 80
normal: 800-1200 dynes.sec/cm5
Pulmonary vascular resistance (PVR)
PVR = [(MPAP - PCWP)/CO} x 80
normal: 20-120 dynes.sec/cm5
Dopamine
low dose (1-3 ug/kg/min)- receptors in kidney and intestine, increases blood flow
med dose (3-10 ug/kg/min)- beta receptor agonist, increase in cardiac contractility, incr CO
high dose (>10 ug/kg/min)- alpha agonist and vasoconstrictor
Dobutamine
affects both beta-1 and -2 receptors, increase in cardiac output, vasodilation
Norepinephrine
alpha agonist, vasoconstriction, mild beta activity, some increase in cardiac contractility
Epinephrine
alpha agonist, some beta agonist effect. vasoconstriction and increased cardiac output
Phenylephrine
alpha agonist, pure arterial constriction
Nitroprusside
primarily arterial vasodilator
reflex tachy, metabolite is cyanide
Nitroglycerin
primarily venodilator, coronary artery dilator
Shock
inadequate tisse perfusion to maintain normal cellular metabolism
Hypovolemic shock
most common type of shock, hemorrhage most common cause. perfusion defect due to blood loss (decreased preload) -> decreased CO
loss of RBC volume reduces O2 carrying capacity (Hgb)
Tx: volume replacement (2 x IV), stop blood loss
Cardiogenic shock
inadequate cardiac performance -> decreased CO
most commonly related to MI, also CHF, valvular disease
central venous pressures are elevated
Tx: inotropic support (dopa or dobutamine), nitro to reverse cardiac ischemia
Neurogenic shock
loss of sympathetic tone -> peripheral vasodilation -> relative hypovolemia, decreased cardiac performance
can be result of vasovagal response, cervicothoracic spinal cord injury, spinal anesthesia
Tx: volume resuscitation, consider phenylephrine or NEpi if unresponsive to volume replacement
Septic shock
toxins released by microbes -> hyperinflammatory derangements, hypovolemia, cardiac dysfunction, vasodilation
Tx: volume resuscitation, central venous access, consider dobutamine if SvO2 < 70%, consider NEpi or dopa if MAP < 65 mmHg
Obstructive shock
physical obstruction that decreases cardiac output (ex: tension pneumo, cardiac tamponade, massive PE, venous air embolism)
Tx: volume resuscitation, correct underlying condition.
Miscellaneous shock
cyanide toxicity, severe hypoxia, normovolemic severe anemia, profound hypoglycemia, anaphylaxis
Carcinoma
malignancy from epithelium
Adenocarcinoma
malignancy from epithelium with glandular component
Sarcoma
malignancy from mesodermal tissues
Steps necessary for malignancy
- expression of cell adhesion molecules
- produce extracellular matrix molecules
- produce cytoskeletal proteins for motility
- produce angiogenic factors for neovascularization
Classic symptoms of cancer
CAUTION Change in bowel or bladder habits A sore that does not heal Unusual bleeding or discharge Thickening or lump in the breast or elsewhere Indigestion or difficulty swallowing Obvious change in a wart or mole Nagging cough or hoarseness
Postop fever
- Wind - post op days 1-3
- Water - UTI, post op days 3-5
- Wound infections - post op days 5-8
- Walk - venous complications
- Wonder drugs
Indications for operative repair of fistula
FRIEND Foreign body at fistula Radiation injury Injured bowel or inflammatory bowel disease Epithelialization of fistula tract Neoplasia or cancer Distal obstruction beyond fistula
symptomatic anemia
tachycardia oliguria hypotension fatigue syncope tachypnea dyspnea transient ischemic attack
preoperative risk factors for mortality in noncardiac surgery
Admission serum albumin ASA class Disseminated cancer Emergency operation Age Blood urea nitrogen (BUN) > 40 mg/dL DNR orders Operation complexity score SGOT > 40 IU/mL Weight loss > 10% in 6 months Functional status WBC > 11,000/mm3
Perioperative pulmonary edema
Causes: Volume overload
Cessation of positive pressure ventilation (increase in preload)
Anesthetic induced myocardial depression
Postop HTN
70% develop within first hour after surgery
Indications for emergent dialysis
AEIOU metabolic Acidosis, can't give bicarb Electrolyte - hyperkalemia Intoxication of medication volume Overload, severe Uremia - pericarditis, mental status changes, asterixis
Anterior mediastinum
from sternum to pericardium
contains thymus, lymph nodes, ascending and transverse aorta, great veins
Visceral mediastinum
from pericardium to anterior longitudinal spinal ligament
contains pericardium, heart, trachea, hilar structures of lung, esophagus, phrenic nerves, lymph nodes
Paravertebral sulci
potential spaces
contain sympathetic chains, intercostal nerves, descending thoracic aorta
Immediate life-threatening thoracic injuries
- Airway obstruction
- Tension pneumothorax
- Open pneumothorax
- Massive hemothorax
- Cardiac tamponade
- Flail chest
Potentially life-threatening thoracic injuries
- Tracheobronchial disruption
- Aortic disruption
- Diaphragmatic disruption
- Esophageal disruption
- Cardiac contusion
- Pulmonary contusion
Most common chest wall deformity
Pectus excavatum (funnel chest)
Poland’s syndrome
unilateral absence of costal cartilages, pectoralis muscle, and breast
Thoracic outlet syndrome (TOS)
compression of neurovascular bundle at thoracic outlet. Brachial plexus compression occurs most offen, vascular compression less frequently
Common metastatic pulmonary tumors
Colorectal
Breast
Melanoma
Renal
Anterior mediastinum mass
4 T's Thymoma Teratoma - from branchial cleft pouch Terrible Lymphoma Tumor- Germ cell (seminoma, embryonal cell carcinoma, teratocarcinoma, choriocarcinoma, endodermal sinus)
Classic triad of mitral stenosis
apical diastolic rumble
opening snap
loud first heart sound
Coronary artery disease risk factors
HTN Smoking Hypercholesterolemia Family history of heart disease DM Obesity
Stable angina
Unchanged for a prolonged period
Unstable angina
recent change from previously stable pattern, includes new-onset angina
Angina at rest
unprovoked by activity
Graft of choice for CABG
Internal mammary artery (IMA) - 90% 10 year patency
Tumors with mets to heart
Melanoma
Lymphoma
Leukemia
Acute pericarditis
Bacterial infection Viral infection Uremia Traumatic hemopericardium Malignant disease Connective tissue disorders
Most common congenital heart defect
Ventricular septal defects (conoventricular most common)
Eisenmenger’s syndrome
Development of higher pulmonary vascular resistance that leads to reversal of flow across ventricular septal defect
Tetralogy of Fallot
- Obstruction of right ventricular outflow
- Ventricular septal defect (VSD)
- Hypertrophy of right ventricle
- Overriding aorta
wet gangrene
infection within nonviable tissue
Pentoxifylline
for intermittent claudication
reduces blood viscosity by decreasing plasma fibrinogen and platelet aggregation
GI upset
Leriche syndrome
buttock and thigh claudication
absent femoral pulses
impotence (males)
Acute lower extremity ischemia
“5 P’s”
- Pain
- Pallor
- Paralysis
- Paresthesias
- Pulselessness
Thrombolytic contraindications
sensory and motor changes on presentation recent surgery (< 2 wks) known intracranial pathology
Acute mesenteric ischemia
surgical emergency, 80% mortality
severe abd pain, out of proportion to PE findings
caused by: embolization, thrombosis, nonocclusive ischemia (ex: cardiogenic shock)
Riolan’s arch
collateral blood supply between SMA and IMA
most common causes of renal artery stenosis
atherosclerosis
fibromuscular dysplasia
risk factors for AAA
Age
Smoking
HTN
Family history
Men > Women 4:1
Ruptured AAA Dx
1 Severe pain 2 Pulsatile, tender abdominal mass 3 Shock (elevated HR, unstable BP, or syncope)
Ischemic cholitis
suspect with post-op diarrhea, stool is heme +
Tx: Hartmann’s procedure: resect necrotic colon, proximal colostomy, distal closure
Artery supply to spinal cord
artery of Adamkiewicz, arises between T8-T12
classic anterior spinal artery syndrome
Paraplegia
Rectal and urinary incontinence
Loss of pain and temp sensation
Preservation of vibratory and proprioceptive sensation
Raynaud’s phenomemnon
associated with scleroderma and collagen vascular diseases.
Milroy’s disease
Lymphedema that is both congenital and hereditary
Chief cells
found in fundus of stomach
secrete pepsinogen -> pepsin
stimulated by cholinergic impulses, gastrin, secretin
Oxyntic/Parietal cells
found in body/fundus of stomach
produce hydrochloric acid and intrinsic factor
stimulated by gastrin
G cells
found in antrum of stomach
secrete gastrin
Carcinoid syndrome
flushing
diarrhea
bronchoconstriction
tricuspid and pulmonary valve disease
only in pts with liver mets or primary extraintestinal carcinoid
Crohn’s disease surgery indications
intestinal obstruction- most common
abscesses and fistulas
perforation, hemorrhage, intractible sxs- less common
most common diverticulum of GI tract
Meckel’s diverticulum
2 ft from ileocecal valve
Familial Adenomatous Polyposus
autosomal dominant
mutation of APC gene on chrom 5
Amsterdam criteria for HNPCC
Three+ relatives with colon cancer (1 first deg)
Colorectal carcinoma in 2+ generations
1+ diagnosed before age 50
Colon cancer risk factors
Family history Ashkenazi Jews Personal history of colorectal cancer Personal history of colorectal polyps Chronic inflammatory bowel disease (UC>Chr) Age > 50 Diet (high fat, low fruit/veg, high calcium) low activity level Obesity DM Smoking EtOH
most sensitive indicator of recurrent colorectal cancer
CEA- glycoprotein secreted by colorectal tumors
if rising- CXR and abd CT
(nonspecific, also high in cirrhosis, pancreatitis, renal failure, UC, other cancer, smoking)
fulminant colitis with toxic megacolon
Dilation of transverse colon
Abdominal pain, tenderness, distention
Fever, leukocytosis, hypoalbuminemia
Risk of colonic perforation
serologic markers for IBD
pANCA (UC)
ASCA (CD)
Sulfasalazine
main medical treatment for UC
Sclerosing cholangitis
UC > CD
Immunosuppressives for IBD
6-Mercaptopurine
Azathioprine
Methotrexate
IV cyclosporine
most common benign hepatic tumor
Hemangioma
benign hepatic tumor strongly associated with oral contraceptives and androgenic steroid use
Hepatocellular adenoma
sulfer-colloid scan
distinguish between Focal Nodular Hyperplasia and a hepatocellular adenoma: FNH takes up sulfer-colloid, adenoma does not
benign hepatic tumor of children
Infantile Hemangioendothelioma
has malignant potential
Most common primary malignant tumor of liver
Hepatocellular carcinoma
risk factors for hepatocellular carcinoma
Chronic hep B
Cirrhosis
Hemochromatosis
Schistosomiasis and other parasitic infection
Carcinogens- polycholirnated bipheyls, chlorinated hydrocarbos, vinyl chloride, nitrosamines
most common primary malignant liver tumor in children
Hepatoblastoma
tumor from bile duct epithelium
Cholangiocarcinoma
Pringle maneuver
control and compression of porta hepatis
used for hemostasis after liver trauma
Vasopressin
potent vasoconstrictor, lowers portal pressure
Somatostatin
causes splanchnic vasoconstriction, fewer side effects than vasopressin
TIPS
Transjugular intrahepatic portosystemic shunt
between a hepatic vein and a branch of the portal vein
Salt and water retention in liver failure
Due to hyperaldosteronism -> decreased aldosterone breakdown by liver
Tx: diuretics, especially aldosterone antagonists
Increase bile flow
Vagal and splanchnic stimulation Secretin Theophylline Phenobarbital Steroids
Release of bile
Colecystokinin (CCK)- humoral control
vagal and splanchnic nerves also contribute
Acalculous cholecystitis
acute or chronic cholecystitis in the absence of stones
acute from burns, sepsis, trauma, or collagen vascular disease
chronic also called biliary dyskinesia
Turner’s sign
flank eccchymoses from blood dissection of flank tissues
sign of retroperitoneal hemorrhage from sever pancreatic inflammation and necrosis
Cullen’s sign
periumbilical ecchymosis from blood dissection up falciform ligament
Adrenal cortex
zona glomerulosa- mineralocorticoids (aldosterone)
zona fasciculata- glucocorticoids (cortisol)
zona reticularis- androgens and estrogens
Superior parathyroid origin
fourth branchial pouch
close to origin of thyroid
abnormal location- within thyroid, or posterior mediastinum
Inferior parathyroid origin
third branchial pouch
close to thymic anlage, cross superior in descent
Tx for symptomatic hypocalcemia
IV Ca2+ gluconate (severe)
Thymus embryology
Third branchial pouch
descends into anterosuperior mediastinum
Sxs of myasthenia gravis
ptosis double vision dysarthria dysphagia nasal speech weakness of arms and legs
Path of myasthenia gravis
autoantibodies against ACh receptors
Tx of MG
Medically- neostigmine, pyridostigmine (drugs that stimulate NMJ)
Surgically- thymectomy
- post-op plasmapharesis
MEN I
Hyperparathyroidism
Pancreatic tumors (nonbeta islet cell- ZE synd)
Pituitary tumors
Sxs of MEN I
hypercalcemia
hypoglycemia
peptic ulcer (pancreatic gastrinoma)
pituitary mass complaints
MEN 2A
Medullary thyroid carcinoma (medullary hyperplasia of C cells- increased calcitonin)
Pheochromocytomas (B/L)
Parathyroid hyperplasia
MEN 2B
Medullary thyroid carcinoma
Pheochromocytomas
Marfanoid/multiple mucosal neuromas
APUD cells
Amine Precursor Uptake Decarboxylation cell system
APUDomas
Insulinomas Gastrinomas (Z-E synd) Glucagonomas VIPomas (vasoactive intestinal peptide) Somatostatinomas
Pancreatic cholera (WDHA syndrome)
Watery Diarrhea
Hypokalemia (high potassium in stool from hypersecretion)
Achlorhydria
severe diarrhea due to hypersecretion of a pancreatic nonbeta islet cell tumor
