Anaesthesia Flashcards

Question

- Name one depolarising muscle relaxant. What is: 1. It used for 2. It's dose 3. The SEs

Answer 1

_Suxamethonium_ _Use_: 1. Rapid intubation of the trachea and short periods of neuromuscular blockade. 2. Rapid sequence induction _Dose:_ 1 - 1.5 mg/kg _SEs:_ * Bradycardia * Muscle pains (due to fasciulations before paralysis) * Hyperkalaemia * ↑ICP, IOP and gastric pressure * Anaphylaxis - skin rash ► bronchospasm * Malignant hyperthermia * **Suxamethonium apnoea**

Answer 2

* Suxamethonium = metabolised by plasma cholinesterase (usually 5-10mins) - some PTs lack /have an altered enzyme ∴ ↓ metabolism * ∴ PTs may = paralysed for many hrs after administration * Pts must be anaesthetised/ventilated until after sux eliminated (slow!)

Answer 3

_Short_: Atracurium, mivacurium (aka nevercurium - hardly used!) (**10 letters, earlier in alphabet!**) _Intermediate_: vecuronium, rocuronium\*\* (**10 letters, later in alphabet**) _Long:_ Pancuronium (**11 letters!)**

Answer 4

- Slow onset and variable duration, therefore less side effects - Stimulate histamine release - ↓BP (vasodilation), ↑HR, Flushing

Answer 5

* Myasthenia gravis or myasthenic syndrome * Extremely sensitive to their effects.

Answer 6

**Neostigmine** **Mech**: Reversible, anti-cholinesterase ► prevents ACh breakdown ∴ ↑ACH **SEs**: Stimulates both nicotinic and muscarinic receptors (parasynp) * **Nicotinic:** _low dose:_ muscle contraction. _High dose:_ block neuromuscular transmission (↑↑↑acetylcholine) * **Muscarinic:** **_↓HR_**, **_bronchoconstriction_** (↑bronchial secretions), miosis, salivation, ↑GI tone/secretions/motility, N&V,

Answer 7

* Anti-muscarinic agent: **Glycopyrrolate** * ∴ prevents muscarinic SEs ass with neostigmine: * ↓bradycardia * ↓ salivary, tracheabronchial, pharyngeal, gastric, secretions * SEs: cant see, cant pee, cant spit, cant shit,

Answer 8

Anti-emetic agents: * 5HT3 blockers: Ondansetron - prevention and Tx of PONV (esp chemo/RT) * Anti-histamine: Cyclizine - opioids, GA, RT and vestibular. * Steroids: Dexamethasone (8mg Adults, 150mg/kg children) ► unclear mech. Tx for chemo and PONV. * Dopamine antagonists: Phenothiazides (e.g. Prochlorperazine) * Anti-dopaminergic: Metoclopramide * Benzodiazepines - Lorazepam - sedative/amnesic/antiemetic **Acupuncture** * Point P6 (2.5-5cm proximal to distal wrist crease. Between flexor carpi radialis and palmaris longus tendons). * 5 mins manual/electical stimulation ↓ vomiting incidence

Answer 9

**Patient factors** - young, female, history motion sickness, anxious, non smoker **Anaesthetic factors** - opioids, etomidate, N2O, volatile **Surgical factors** - gynae, abdominal, middle ear, neurosurgery, ophthalmic (e.g. squint), prolonged op times, poor pain control post op

Answer 10

_Vasoactive agents_ Commonly used: * Ephedrine * Phenylephrine * Metaraminol Severe hypotension / ICU * Noradrenaline * Adrenaline * Dobutamine

Answer 11

**Mech**: Activates α1 (indirectly), β1, β2 **Effects**: HR ↑, MAP ↑ (contractility), CO ↑ PVR ± **SEs**: Repeated doses less effective (tachyphylaxis)

Answer 12

**Mechs:** α1 (weak α2, weak β1) **Effects:** HR ↓, MAP ↑↑, CO ↓, PVR ↑↑ **SEs:**

Answer 13

Mechs: Activates α1 (indirectly), β1, β2 Effects: Vasoconstriction - ↑ systolic/diastolic BP, ↑PVR

Answer 14

Neonate - 80% 6 Months - 70% 1 yr - 60% Young Adult - 60% Elderly - 50%

Answer 15

* Distributed into different compartments/spaces - seperated by membranes that regulate flow of water between compartments * **Intracellular Fluid (ICF)** - 2/3s (30L) of total body water * **Extracellular Fluid (ECF)** - 1/3 (15L) * Interstitial fluid (ISF) (10L) - occupies spaces between cells * Intravascular fluid (3.5L) - blood plasma * Transcellular Fluid (1.5L) - intraocular fluid, CSF, urine in bladder, fluid in bowel lumen

Answer 16

A liquid/ solid/gas which is able dissolve another solid/liquid/gas (solute\*) to form a solution e.g. water + salt Solute - a dissolved substance e.g. glucose

Answer 17

Both quantify how much of a solute is dissolved in a solution i.e. the solute concentration of a solution * _Osmolarity_: the number of osmoles of solute particles per **unit volume** of solution (milliosmole) * _Osmolality:_ the number of osmoles of solute particles per **unit weight** of solvent (milliosmoles/kg)

Answer 18

* Describes the **relative solute concentration** of two solutions seperated by a **selectively permeable (semi-permeable) membrane** (e.g. ICF and ECF) * Tonicity = influenced by **number of solute particles within a solution** (which cannot cross membrane) * **Hypertonic** (contains a higher concentration of solute on one side of the membrane) * **Isotonic** (contains the same concentration of solute on both sides of the membrane) * **Hypotonic** (contains a lower concentration of solute on one side of the membrane)

Answer 19

* Movement of water from less concentrated solution (hypotonic) to a more concentrated (hypertonic) solution across a semipermeable membrane * Semi-permeable membrane - allows free passage of water, but NOT any solutes Osmotic pressure - minimum pressure which needs to be applied to a solution to prevent the inward flow of its solvent across a semi-permeable membrane

Answer 20

**Interstitial and intravascular compartments** * Seperated by capillary wall (water crosses via gaps/through cell membrane) * Movement of H2O/solutes = largely passive (simple diffusion/filtration) **Cell membrane - allows passive movement** * Water/small uncharged/lipid soluble molecules able to cross via passive diffusion * Ions, glucose (facilitated diffusion), proteins via transmembrane proteins or ion channels (act to provide different permeability to different solutes) * Steady state - ECF and ICF = isotonic * Any difference in EC/IC tonicity = due to change in solute concentration in either fluid compartment * H2O then moves from area of relative hypertonicity ► hypotonicity

Answer 21

* Na+ - memebrane = impermeable to Na+ ions so extracell conc governs movement between ECF and ICF * Extracell Na conc = controlled by kidneys and neuroendocrine controls * K+ = major intracell ion

Answer 22

* Loses from **non-urine sources** - insensible losses incease in unwell patients (febrile, tachypnoeic, increased bowel movements/stoma output)

Answer 23

* **Crystalloids** - NaCl 0.9%, Dextrose, Dex/Sal, Hartmanns * **Colloids** - gelatins (Gelofusine, voluven, Volulyte), RBCs, Albumin (HAS)

Answer 24

* Thirst * Dry mucous membranes * ↓Skin turgor (sturnum) * Urine output \<0.5ml/kg/hr (Oliguria) Ongoing losses * ↑Cap refill time * ↓BP ↑HR * ↓JVP/CVP Monitor fluid input-output chart, daily weight chart and U&Es regularly

Answer 25

Mild - ↓weight (4%), ↓skin turgor, dry mucous membranes Moderate - ↓weight (5-8%), oliguria, ↓BP ↑HR Severe - ↓weight (\>8%), profound oliguria, CVS collapse

Answer 26

* Balanced salt/electrolyte solutions. Forms true solution and is capable of passing through semi-permeable membranes * Can be isotonic, hypertonic or hypotonic * Uses: Plasma expanders * ↑ the intravascular/circulatory volume via movement of intracellular and interstitial water into intravascular space * e.g. haemorrhage, dehydration or surgical fluid loss

Answer 27

**Advantages** * Short half life (30-60mins) * Inexpensive, readily avaliable * Non-allergenic **Disadvantages** * 3x volume needed for replacement (Molecules = small enough to freely cross capillary walls ∴ 2/3s of infused volume fluid will move into tissues) * Excessive use: peripheral and pulmonary oedema

Answer 28

* 9 g of NaCl/L water * 154 mmol/L sodium * 154 mmol/L chloride * Osmolality = 308 mosm/L * Does not contain the same electrolytes in the same concentrations as extracellular fluid (135- 145) • Potential problem = hyperchloraemic metabolic acidosis, more likely with renal insufficiency

Answer 29

* Normal saline (0.9% NaCl) * Hartmanns solution * Lactated Ringer's * Hypertonic Saline (3, 5, 7.5%) * Ringer's solution

Answer 30

* Na+: 131 mmo/l * Cl = 111 mmol/l * Lactate = 29 mmol/l * K = 5 mmol/L * Ca = 2mmol/L * Isotonic - distributes across extravascular space * Potential SEs: K+ may accumulate

Answer 31

* Hypertonic saline solutions include 1.8%, 3%, 5%, 7.5% and 10% sodium chloride solutions * Osmolality = exceeds intracellular water. the extracellular fluid (ECF) becomes slightly hyperosmolar thus gradient formed i.e. cell water ► extravascular space * Comps: ↓intracellular volume (cellular dehydration), hypernatraemia?

Answer 32

* Only water and dextrose (5% i.e. 50g/L) - Glucose taken up by cells and water distributes quickly across all fluid compartments * Contains no electrolytes so decreases blood osmolality by dilution * 1 g Dextrose 3.4 Kcal * Calorific value approx. 170 kcal

Answer 33

* Contain NaCl and large chemicals (proteins/starches) which are incapable of passing across a semi-permeable membrane. * Thought to increase oncotic pressure ► increase intravascular volume * Synthetic: * Gelatine based - dextrans * Starch based - Glesofusin (**banned in 2013 - hyperoncotic ►AKI; anaphylaxis, coagulopathy**) * Human protein products * Blood products: RBS, platelets, FFP * Human Albumin Solution (HAS)

Answer 34

* Anaphylactic reactions * Coagulopathy * Cost

Answer 35

* Individualise to the particular patient * Assess current fluid status * Replace any deficit * Maintenance fluids / electrolytes * Replace ongoing losses

Answer 36

Water - 30-40 ml/kg (35ml/kg if elderly) Energy - 30-40 kcal/kg Na - 1-2 mmol/kg K - 1mmol/kg Glucose - 50g/day

Answer 37

* Water = 70 x 40 = 2800ml * Na = 70 x 1-2 = 70-140 mmol * K = 70 mmol * 50g Glucose/day 1st bag: 1L 0.9% saline/Hartmanns over 8hrs 2nd Bag: 1L of 5% dextrose + 20mmol/L K 3rd: 1L of 5% dextrose + 20mmol/L K **Total:** - 3000ml Water - Saline: 154 mmol Na/Hartmanns: 131 mmol Na - 40 mmol K -

Answer 38

**Reduced intake** (high urea:creartinine, high PCV) * Elderly, dysphagia, unconscious **Increased Requirements** * Trauma, burn, post-operative **Increased Loss** * Fever/sweating * Hyperventilation * GI loss: vomiting (low K, low Cl, alkolosis), diarrhoea (low K, acidosis) * Renal loss (↑ diuresis - e.g. diuretics) * Third space losses e.g. lumen (bowel obstruction), retroperitoneum (e.g. pancreatitis),

Answer 39

* Prescribe for routine maintenance requirement plus additional fluid and electrolyte supplements to replace the ‘measured’ abnormal ‘ongoing’ losses * (refer to table and prescribe according to source of loss)

Answer 40

* To maintain intravascular volume (in order to maintain blood pressure) e.g. hypovolaemic/cardiogenic/distributive shock * To replace massive fluid losses (may require blood transfusion + other blood products) * AIM: ↑volume to ↑BP

Answer 41

* Crystalloids (0.9% sodium chloride) 500 ml fluid bolus over less than 15 minutes. * If fluid resus still required, repeat bolus. * If \>2000ml given and fluid resus still required, seek expert help

Anaesthesia Flashcards

(72 cards)