2. Difficult Airway
"The difficult airway is something one anticipates, the failed airway is something one experiences" - Ron Walls
Difficult airway can be due to:
1. Difficult Bag Valve Mask (BVM); mnemonic = MOANS
2. Difficult laryngoscopy and dificult intubation; mnemonics = LEMON
3. Difficult cricothyrotomy; mnemonic = SHORT
4. Difficult extraglottic devices; mnemonic = RODS
Note:
In the 2nd edition of Ron M. Wall's Manual of Emergency Airway Management, it was only mentioned of the 3 dimensions of difficult airway, namely the first three mentioned: difficult BVM, difficult laryngoscopy and intubation and difficult cricothyrotomy. This is known as the Sakle's triangle. In the 3rd edition of that book, the 4th dimension, difficult extra-glottic devices is added in.
1. Difficult BVM = MOAN!
M = Mask seal not good, e.g. beard, facial deformity, etc
O = Obesity (difficult ventilate), 3rd trimester pregnancy, or obstruction e.g. neck swelling, angioedema, hematomas, cancer, etc
A = Age, elderly, loss of muscle tone to support the upper airway
N = No teeth (no teach causing caved in face)
S = Stiff lungs - upper airway obstruction - exacerbation of asthma, COPD, etc
2. Difficult laryngoscopy: use LEMON
L = Look externally, e.g. short neck, large tongue, large teeth, etc
E = Evaluate 3-3-2
- 3 = adequacy of oral access
- 3 = to assess capacity of mandibular space to accommodate tongue
- 2 = distance of larynx to level of base of tongue
M = Mallampati scoring
- Difficulty to sit up; use tongue depressor, etc
- difficult to do proper, complete Mallampati
O = Obstruction
Any signs of upper airway obstruction?
three cardinal signs of upper airway obstruciton:
- muffled voice (hot potato voice),
- difficult swallowing secretions,
- stridor; when stridor happens, consider that circumference of airway reduced to roughly 10% of normal caliber!!!!
N = Neck mobility
3. Difficult cricothyrotomy
S = previous surgery
H = Hematoma/swelling around neck
O = Obesity
R = Radiation distortion
T = Tumor
4. Difficult Extraglottic devices
R = Restrictied mouth opening
O = obstruction upper airway
D = Disrupted or distorted upper airway
S = stiff lungs, spine of cervical
3. Acute Deterioration in Intubated Patient:
Four common causes of acute deterioration in any intubated patient are recalled by the mnemonic DOPE
D = tube Displacement
O = tube Obstruction
P = Patient (this is the first priority, not the machines), Pneumothorax, and
E = Equipment failure).
Neuroscience
1. Features in CT Scan to screen for:
"Blood Can Be Very Bad"
B = Blood clots - extradural, subdura, intra-parenchyma
C = Cistern - cisterns patent? suprasellar, quadrigeminal. etc
B = Brain parenchyma - Sulci-gyri differentiation, cerebral edema, diffuse axonal injuries features; any lesions? perilesional edema?
V = Ventricles - normal? dilated?
B = Bone. Any fracture?
Medicine
1. Diabetic Ketoacidosis
Triad of DKA is D.K.A.
Diabetics with sugar more than 14 mmol/l
Ketonemia +ve at 1:2 dilution or Ketonuria at least 3+
Acidosis with pH less than 7.3
Note: Remember: 14 and 15
1.2. The signs and symptoms of DKA is D.K.A.
D = Delirium, diuresis, dehydrated (3D)
K = Kussmaul breathing, ketotic breath (2K)
A = Abdominal pain (1A)
1.3. The precipitating factors of DKA is SSSSS..................
S = Sepsis
S = Surgery
S = Stress
S = Sugar high due to skipped insulin
S = Substance abuse, dope, alcohol
Formula
1. For the insulin infusion sliding scale, a rough guide to remember would be:
The Insulin Infusion Rate = (RBS Reading) / 5
e.g. RBS = 20, therefore insulin infusion rate = 20/5 = 4u/hour
Monitor RBS hourly.
Ref: Manual of Anaesthesia for Medical Officers by CY Lee
2. Calculated serum osmolality 2 (Na) + Urea + Glucose
Normal = 280 - 300 mmol/l
High osmolar gap is when the actual measured osmolality is greater than 10 mmol/l compared to calculated osmolality
3. Bicarbonate therapy in severe metabolic acidosis
Target bicarbonate level 8 is 10 mmol/l
Target pH is 7.20
Formula for amount of bicarbonate needed:
0.5 * (target bicarbonate level - current bicarbonate level) * body weight
Example:
Current bicarbonate level 4 mmol/l
Target bicarbonate level 8 mmol/l
Body weight 70 kg
Bicarbonate needed: (8-4)*70*0.5 = 140 mmol/l
Wait for 30 minutes after completion of bicarbonate therapy before repeating ABG and decide for further bicarbonate
Ref:
Adrogue, H. J. Madias, N. E. (1998). Management of life-threatening acid-base disorders. First of two parts. N Engl J Med, 338 (1), 26-34.
2. Concept and Formula In Acid Base Equations:
A. Metabolic Acidosis
Winter's equation:
Expected pCO2 = 1.5 * [HCO3-] + 8 (+/-2)
If the measured PaCO2 is less than the expected → concurrent respiratory alkalosis
If the measured PaCO2 is more than the expected → concurrent respiratory acidosis
Winter’s rule
states that the last 2 digits of pH greater than 7 predicts the PaCO2 in a compensatory respiratory mechanisms
Example:
Pt with metabolic acidosis with pH 7.25, the predicted PaCO2 would be 25 mmHg
Delta Gap = Measured AG – normal AG (Normal AG taken as from 3 - 11, average 7)
Delta gap + measured HCO3- MUST BE equal back to the normal HCO3-
If Delta Gap + measured HCO3 more than normal HCO3-, this means there are too much HCO3-, therefore there is co-existing metabolic alkalosis
If Delta Gap + measured HCO3 less than normal HCO3, there is co-existing normal anion gap metabolic acidosis (besides the wide anion gap metabolic acidosis)
The presence of very high AG (more than 20) suggests wide anion gap metabolic acidosis EVEN IN THE PRESENCE OF NORMAL pH!!!
Bicarbonate therapy
Aim:
Return blood pH to 7.2
↑ plasma bicarbonate 8 to 10 mmol/l
Sodium bicarb needed = (body weight * [target – measured HCO3-] * 0.5) mmol/l
B. Metabolic Alkalosis
Expected PCO2 would be
(0.6 * [HCO3- - 24] + 40) mmHg
If measured PCO2 is less than expected → concurrent respiratory alkalosis
If measured PCO2 is more than expected → concurrent respiratory acidosis
C. Respiratory Acidosis/Alkalosis
In acute setting,
For every 10 mmHg change of PCO2
[HCO3-] changes 1 – 2 mmol/l and
pH changes 0.08
In chronic setting,
For every 10 mmHg change of PCO2
[HCO3-] changes 4 – 5 mmol/l and
pH changes 0.03
D. Partial Pressure of Arterial Oxygen
FiO2
Predicted PaO2 = FiO2 * 6 (FiO2 in percentage; e.g. FiO2 of 1.0 is 100%; therefore expected PaO2 would be 100*6 = 600)
Age
Predicted PaO2 (in supine position) = [100 – 1/3 * (age in years)]
pH of blood
A rise or fall of pH by 0.10 results in PaO2 falls or rise (opposite direction) by 10%
E. PaO2/FiO2 Ratio
A quick way to estimate impairment of oxygenation
Normal PaO2/FiO2 ratio is 500 – 600 (when FiO2 is expressed in decimal)
Example: in PaO2 80mmHg, FiO2 40%, then PaO2/FiO2 ratio is 80/0.4= 200
PaO2/FiO2 is 300 – indicates ALI
PaO2/FiO2 is 200 – indicates ARDS
F. A-a Gradient
A-a gradient = PAO2 - PaO2
Therefore, A-a gradient = (713*FiO2) - (PaCO2*1.25) - PaO2
Normal A-a gradient = 10 – 20 mmHg
Normal A-a gradient for the particular age = (Age/4 + 4)
High A-a gradient in V/Q mismatch, Rt to Lt shunt, diffusion abnormalities
References:
Adrogue, H. J. and Madias, N. E. (1998). Management of life-threatening acid-base disorders. First of two parts. N Engl J Med, 338(1), 26-34.
Leong, B. and Lee, K. W. (2004) In Guide To The Essentials In Emergency Medicine (Eds, Ooi, S. and Manning, P.) McGraw-Hill, Singapore, pp. 158-68.
Causes of High AG Metabolic Acidosis
Mnemonic #1:
CAT MUD PILES
C = Carbon monoxide, Cyanide
A = Alcoholic ketoacidosis
T = Toluene
M = Methanol
U = Uremia
D = Diabetic ketoacidosis
P = Paraldehyde, Phenformin
I = Iron, Isoniazid
L = Lactic acidosis
E = Ethylene glycol
S = Salicylates poisoning
Mnemonic #2:
KUSSMAL
(because metabolic acidosis like sepsis frequently present with Kussmaul breathing; furthermore, KUSSMAL gives the more commonly causes only that we encounter in our setting)
K = dKA
U = Uremia
S = Salicylates poisoning
S = Sepsis
M = Methanol poisoing
A = Alcoholic ketoacidosis
L = Lactic acidosis
Causes of Normal Anion Gap Metabolic Acidosis
Mnemonic #1 (I prefer to use this mnemonic as USED CARP gives the meaning of the wasting or "used up" bicarbs, thus causing NAGMA):
USED CARP
U = Ureteroenterostomy
S = Small bowel fistula
E = Extra chloride
D = Diarrhea
C = Carbonic anhydrase inhibitors
A = Adrenal insufficiency
R = Renal tubular acidosis
P = Pancreatic fistula
Mnemonic #2:
HARD-UP
H = Hyperventilation (chronic)
A = Acetazolamide, Acids (e.g., hydrochloric), Addison's disease
R = Renal tubular acidosis
D = Diarrhea
U = Ureterosigmoidostomy
P = Pancreatic fistulas and drainage
S = Saline (in large amounts) (hyperchloremic metabolic acidosis)
3. The use of CHADS2 score is a scoring system to identify risk factors for developing stroke in patients with nonrheumatic atrial fibrillation.
The acronym of CHADS2 stands for:
C = Congestive Heart Failure
H = Hypertension or treated hypertension
A = Age 75 yrs or older
D = DM
S = Stroke or TIA previously
C-H-A-D each component: 1 point
S (previous stroke or TIA) = 2 points
If patient has 0 point: it is classified under low risk = aspirin daily will do
If patient has 1 point: it is classified under moderate risk: either aspirin, or warfarin with INR target 2 - 3
If patient has 2 or more points: it is classified under high risk: warfarin with INR 2 - 3 is needed
The higher the score, the higher the stroke risk
Patient with mitral stenosis or prosthetic heart valve is classified as high risk, and therefore warfarin is needed.
* The use of warfarin to prevent stroke must be balanced with the risk of developing bleeding due to the use of warfarin.
Ref: Gage BF, Waterman AD, ShannonW, et al. Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. JAMA 2001;285:2864–70
4. Asthma
Common Medications used to treat ASTHMA:
A = Albuterol
S = Steroid
T = Theophylline
H = Humidified Oxygen
M = Magnesium (MgSO4)
A = Antileukotrienes
Pediatrics
Criteria to define SIMPLE Febrile seizure
A Simple Febrile seizure is defined as a seizure in a FEBRILE child aged 6 months to 60 months and without:
S = Seizure of focal type
I = Intracranial infection
M = Multiple times a day
P = Past history of afebrile seizure
L = Last longer than 15 minutes
E = Examination abnormalities
* if there is evidence of the above criteria. then it is a complex febrile seizure
The way to stop importing blog posts on facebook? 'Stop importing' button is just not found.
?
my blog ... Transvaginal mesh Lawyers
Hello, Neat post. There is a problem with your site in internet explorer, may check this?
IE still is the marketplace leader and a large component of folks will pass over your great
writing because of this problem.
my web site: Psn Code Generator
Currеntly it seems like Movablе Type is the best blogging platform аνailable right now.
(from ωhat I've read) Is that what you are using on your blog?
my page: birmingham plumber
First of all I want to say terrific blog! I had a quick question that I'd like to ask if you don't minԁ.
I wаs intеreѕted to finԁ out hοw yоu cеnter уоursеlf and cleаr your thoughts priοг
tο writіng. I have haԁ a tough time clearing my thoughts in getting my іdeaѕ out.
I do enjoy writing hоweveг it ϳust sеemѕ
likе the fіrst 10 to 15 mіnutes are
waѕted just trying to figure out how to bеgin.
Any recommеndatіons or hints? Ϻanу thanκs!
Feel freе to surf to my ωеblog increase boobs naturally
Pleaѕe let me knоw if you're looking for a article author for your weblog. You have some really great posts and I feel I would be a good asset. If you ever want to take some of the load off, I'd love to wгite some material for your blog
in exchange fοr a link back to mine.
Plеasе blast me аn e-mail if interested.
Thank you!
Аlѕο visіt my wеblog bigger breasts