Definition Flashcards
Henderson Hasselback equation
H20 + CO2 = H2CO3 = H+ + HCO3-
Chloride shift
exchange of bicarbonate and chloride across RBC membrane
Buffer
Limit the change of pH by binding or releasing H+
Categories of Acute limb ischaemia
1 - Not immediately threatened
2a - Salvageable, partial sensory deficit
2b - salvageable, partial motor deficit
3 - amputation
reperfusion injury
revascularisation leads to increase venous return from ischaemic tissue containing toxic metabolites
This leads to SIRS - hypotension, MODS, arrythmia
Acute tubular necrosis
Damage to renal tubular cells 2ry to ischaemic insult or nephrotoxin
Causes - hypoperfusion, aminoglycosides, contrast, Mb, myeloma
Acute respiratory distress syndrome
Acute respiratory failure and non cardiogenic pulmonary oedema
Hypoxaemia and reduced lung compliance, which is refractory to Oxygen therapy
Normal pulmonary artery wedge pressure - <18mmHg
PaO2/FiO2 ratio reduces
Pain
unpleasant sensory and emotional experience associated with actual or potential tissue damage
Carried by A delta and C fibres - dorsal horn of spinal cord - thalamus - somatosensory cortex
Allodynia
Increased sensation of pain from normally non painful stimuli
Caused by cross talk of sympathetic or A beta and nociceptive fibres
Neuropathic pain
Results of damage to the pain signalling pathway
present as numbness or burning
Apnoea test
1) increase FiO2 to 1.0 check Sats >95% then lower resp rate
2) Once ETCO2 >6.0, and check PaCO2 >6.0
3) disconnect ventilator and give O2 5L/min via endotrachial catheter for 5mins, if PaCO2 raises by 0.5kPa - loss of respiratory drive
second degree burn
burns that have penetrated into the deep dermal layer of the skin
pink, painful, branches, blisters
Burn’s unit referral
Size - 5% in child, 10% in adults Age - <5, >60 Chemical Electrical Face, Hands, Feet, perineum, flexures, circumferential Inhalation injury
Frank-Starling law
Stroke volume of the heart increases in response to an increase in the volume of blood in the left ventricle
Myoglobin
Oxygen binding protein found in the muscle
Charcot’s triad
RUQ pain, jaundice, pyrexia
Ascending cholangitis
Disseminated intravascular coagulation
pathological consumptive coagulopathy
generation and deposition of fibrin - microvascular thrombi in various organ
Consumption of coagulation factors, platelets and activation of fibrinolysis leads to bleeding
Low Hb, PLt, fibrinogen and high PT/APTT/DDimer
Massive blood transfusion
> 50% of replacement of blood volume in 12 hours
Hypothermia
core body temperature <35
May lead to
metabolic acidosis, hypocalcaemia, cardiac arrythmia, enzyme dysfunction, shift in haemoglobin dissociation curve, platelet dysfunction
Signs of hypovolemia
pale anxious sinus tachy hypotension oliguria cool/clammy slow CRT
Fat embolism
Clinical diagnosis
Circulating fat globules in the circulation and pulmonary parenchyma
Trauma - pelvis, femur, tibia; IM nailing; major burns
Non trumatic - BM transplant, pancreatitis
petechial rash over axilla, neck, sternum
low sats
confusion
Areas of portosystemic shunt
lower oesophagus umbilical retroperitoneal bare area of liver patent ductus venosus upper anal canal
oesophageal varices
bulging veins secondary to back pressure due to portal hypertension at the portosystemic anastomosis
rule of 2/3
2/3 of cirrhosis leads to portal HTN
2/3 of portal HTN leads to oesophageal varices
2/3 of oesophageal varices presents with bleed
Sengstaken Blakemore tube
NG tube with two balloon (one above and below GOJ)
Inflated under radiological guidance
Used for 24 hrs
Can cause ischaemia, perforation, aspiration pneumonia
TIPSS
Tansjugular intrahepatic porto systemic shunt
Hepatic vein is cannulated from IJV using needle under fluoroscopy
Stent is inserted between hepatic and portal vein
Can lead to encephalopathy
False localising sign
6th nerve palsy due to raised ICP/herniation
Compression of the nerve not damage to nucleus
Secondary brain injury
injury insulted secondary to the primary injury
prevented by
Intubation, Sedation, PaCO2 <5.0, nurse at 45 degrees, CVP, Arterial line, ICP monitor, Mannitol
Cerebral perfusion pressure
MAP - ICP
pressure gradient that drives oxygen delivery to the brain
>65mmHg (MAP 90, ICP25)
Cerebral blood flow
autoregulated between 50-150mmHg
regulated by myogenic reflex and C02 and O2
Monroe Kellie doctrine
States that skull contains a certain amount of brain, blood and CSF
Any SOL leads to displace the others
Difference between CSF and plasma
PCO2 is higher Lower pH low protein low glucose high chloride low cholesterol
CSF circulation
Choroid plexus Lateral Ventricles Foramen Monroe Third ventricle Cerebral Aquaduct Fourth ventricle Foramen of Luschka & Magendie Subarachnoid space Arachnoid granulation
Respiration
Transportation of Oxygen to tissue and carbon dioxide outside the tissue
Minute ventilation
RR x tidal volume
Amount of air inspired per minute
Ischaemia
Abnormal reduction in the blood supply or drainage of a tissue/organ
Infarct
consequence of an ischaemic insult resulting in tissue death
Respiratory quotient
ratio of CO2 excretion to O2 consumption which determines which food is being metabolised during cellular respiration
RQ= CO2/O2
Ranson criteria
For non-gallstone pancreatitis Age >55 WCC >16 Glucose >11.2 LDH >350 AST>250
48hrs Hct drop by >10% Urea increase by 1.79 Ca <2.00 PaO2 60mmHg Base deficit 4 Fluid required >6L
Pancreatic pseudocyst
encapsulated fluid collection encased by fibrous capsule caused by leakage of enzyme-rich fluid, usually around 4 weeks
Can form anywhere along the pancreas
Seen in lesser sac obstructing gastroepiploic foramen
shock
inadequate tissue perfusion for metabolic requirement
coronary perfusion pressure
systemic diastolic arterial pressure - left ventricular end diastolic pressure
sedation
alteration in consciousness/analgesia/anxiety
used for diagnostic/therapeutic procedure of short duration
contraindicated - unstable patient, long lasting, no observation
Need to have reversal meds as well
light sedation
maintain airway with intact reflex
respond to stimuli
anxiolytic effect
deep sedation
airway is not necessary patent, may need support
repeated and painful stimuli needed for response
General anaesthesia
airway is not protected
patient not rousable
sepsis
life threatening organ dysfunction due to a dysregulated host response to infection
Septic shock
persistent hypotension requiring vasopressor to maintain a MAP of 65mmHg or having a serum lactate >2 despite adequate volume resuscitation
Steroid
organic compound that contains a characteristic arrangement of 4 cycloalkane rings that are joined together
ASA
American society of anaesthesiologist 1 - healthy 2- mild systemic disease 3 - severe systemic disease 4 - severe systemic disease with constant threats to life 5 - morbidund 6 - brainstem dead
LEMON assessment
Look - facial trauma, small mandible, short neck
Evaluate - 3 fingers between incisors, 3 fingers hyoid to chin, 2 fingers thyroid notch to floor of mouth
Mallanpati score
Obstruction
Neck mobility
