Peri-Operative Care Flashcards
What is Malignant Hyperthermia?
Autosomal Dominant Disorder
Initial muscle rigidity followed by increased temperature under General Anaesthesia
Why should you check the airways in a Pre-Op Exam?
Degree of mouth opening
Teeth (Any loose?)
Palate (Mallampati Classification)
How far can they extend neck
What is the American Society of Anaesthesiologist Grade?
Grades a patient from I-VI, with increasing severity of disease
Subsequently gives a prediction of mortality from anaesthesia
What is a Group and Save?
Done when blood loss is NOT anticipated
Determines blood group/rhesus status/atypical antibodies
No blood is issued
What is a Cross - Match?
Done when blood loss IS anticipated
Mixed with donor blood to see if reaction happens
What should you advise patients regarding eating Pre-Op?
Stop Eating 6hrs before
Stop clear fluids 2hrs before
To prevent Aspiration Pneumonitis (gastric contents) or Aspiration Pneumonia (direct inhalation)
Using the mnemonic CHOW, what medications should be stopped Pre - Op?
Clopidogrel (7d before)
Hypoglycaemics
Oral Contraceptives/HRT (stopped four weeks before)
Warfarin (5d before)
How are T1DM patients managed Pre-Op? Give three features
- Should be first on the morning list
- Reduce the insulin dose by a 1/3 the night before
- Omit morning insulin and set up sliding scale of Actrapid
How are T1DM patients managed Post-Op?
After Op give SC Insulin 20 mins before first meal
Stop IV infusion 30-60 mins after first meal
How are T2DM patients managed Pre-Op? Give three features
- Metformin stopped the morning of the Op
- Others stopped 24hrs before
- Patients put on sliding scale of Insulin, given 5% Dextrose and managed the same as T1DM
How should Steroids be adapted in an operative scenario?
- Need to be continued due to risk of Addisonian Crisis
- HPA axis increases its activity in surgery due to ‘stress state’ which may end up supressing steroids
- Stress dose should be given
All Operative patients are started on LMWH, give an exception
Head and Neck Surgery
Give three contraindications to TED Stockings
Severe Peripheral Vascular Disease
Recent Skin Graft
Severe Eczema
Give three indications for prophylactic antiobiotics
Orthopaedics
Bowel Surgery
Vascular Surgery
What Bowel Procedures require preparation? How would you do so?
Left Hemicolectomy/Sigmoidectomy/AP Resection/Anterior Resection - Phosphate Enema the morning of
Give four key considerations for fluid management
What is the aim? (Rescucitation/Maintenance/Replacement)
Most recent electrolytes
Comorbidities
Weight and Size
Describe the distribution of fluid in a 70kg man
42L Total
28L - Intracellular
14L - Extracellular (11L interstitial, 3L circulating)
Describe the target fluid compartment for different purposes
General Hydration - distributed across all fluid compartments
Rescucitation - Intravascular
Explain the fluid consideration in septic patients
Tight junctions between capillary endothelium breaks down causing fluid to leak out into tissues (therefore large volumes of IV fluid may be needed)
State four fluid outputs
Urine
Sweating
Respiration
Faeces
Give 4 features of fluid depletion OE
Reduced Skin Turgor
Decreased Urine Output
Orthostatic Hypotension
Increased Cap Refill Time
Give 2 features of fluid overload OE
Raised JVP
Oedema
State the daily requirements of Water, Na+, K+, Glucose
Water - 25ml/kg/d
Na+ - 1mmol/kg/d
K+ - 1mmol/kg/d
Glucose - 50g/d
What is a Crystalloid Fluid?
Contains mineral salts
Cheaper so used more often
Saline/Dextrose/Hartmanns
What is a Colloid Fluid?
Contains larger molecules
Higher Osmotic Pressure
Volplex/Blood
Give 2 examples of pathological fluid loss
Bowel Lumen in Bowel Obstruction
Retroperitoneum in Pancreatitis
At what concentration of Haemoglobin is a transfusion recommended?
<70g/L
Why is Rhesus D Status an important consideration in blood transfusions
- Not important if not pregnant as patients won’t attack their own RBC
- In pregnancy if first child is Rh positive to a Rh negative mother, antibodies against Rh will be formed, which will cause HND in second child
State the Universal Donor and the Universal Acceptor
Donor - O neg
Acceptor - AB pos
Who should be given CMV negative blood?
Pregnant Women, Intrauterine Transfusions, Neonates (<28d)
Can cause sensorineural deafness
Give 3 clinical features of administering blood
- Observations before/15 to 20 mins in/1hr/Completion
- Given through Grey (16G) or Green (18G) to reduce the risk of haemolysis
- Given via blood giving set (which includes a filter)
Give 3 clinical features of RBC transfusion
- Contains RBC only
- Indicated in Acute Blood Loss or Symptomatic Anaemia
- Given over 2-4 hrs
Give 2 clinical features of Platelets transfusion
- Indicated in Haemorrhagic Shock, Profound Thrombocytopenia, Low Pre-Op Platelet
- Given over 30mins
Give 3 clinical features of FFP transfusion
- Contains Clotting Factors
- Indicated in DIC, Haemorrhage Secondary to Liver Disease, All Massive Haemorrhages
- Given over 30 mins
Give 2 clinical features of Cryoprecipitate transfusion
- Contains Fibrinogen, VWF, Factor VIII, Fibronectin
- Indicated in DIC with low fibrinogen or VWF, or massive haemorrhage
Give 2 scores which can be used to assess nutritional status
BMI
MUST Score
State the Hierarchy of Feeding Options
- Oral Nutritional Supplements
- NG Tube
- PEG/RIG
- Jejunostomy
- Intestinal Failure
Albumin levels were thought to be an indicator of nutritional status, why is this not the case?
Patients with Anorexia Nervosa have normal Albumin levels
How should nutrition be managed in an Enterocutaneous Fistula?
High - Enteral/Parenteral Nutrition
Low - Low Fibre Diet
Give four medical managements of a High Output Stoma
Reduce Hypotonic Fluids
Loperamide
PPI
Low Fibre
What is a High Output Stoma?
A high output stoma (HOS) is when the output causes the patient to become water, sodium and magnesium depleted.
Give three advantages of day case surgery
- Cheaper
- Lower infection rates
- Reduces waiting list
Give four requirements in order for a procedure to be able to be done as a day case
Minimal Blood Loss expected
Short operating time
No expected complications
No requirements for specialist aftercare
State three types of Haemorrhage
- Primary - Occurring within the intra-operative period
- Reactive - Occurring within the first 24 hours of surgery (due to slipped ligature or missed vessels from intraoperative hypotension and vasoconstriction)
- Secondary - Occurring 7 to 10d post op, normally infective erosion
Other than visible bleeding, give four clinical features of Haemorrhage
Tachycardia
Dizziness
Agitation
Reduced UO
State the classification of Haemorrhage from I-IV
I - <15% blood loss
II - 15-30% blood loss
III - 30-40% blood loss
IV - >40% blood loss
How does Haemorrhage post Neck Surgery present?
Primary Sign is airway obstruction - because pretracheal fascia only distends so far
What vessel is most at risk during Laproscopic procedures?
Inferior Epigastric Artery
Runs from External Iliac up Mid-Clavicular line
Define SIRS
- Systemic Inflammatory Response Syndrome
- Two or more of the following criteria: tachycardia (heart rate >90 beats/min), tachypnea (respiratory rate >20 breaths/min), fever or hypothermia (temperature >38 or <36 °C), and leukocytosis, leukopenia, or bandemia (white blood cells >1,200/mm3, <4,000/mm3 or bandemia ≥10%)
Define Sepsis
- SIRS + Evidence of Infection
- Life threatening Organ Dysfunction due to dysregulated host response to infection
Define Septic Shock
- Perisistent Hypotension despite fluid rescucitation
Describe the qSOFA score
RR>22/min
Altered Mental State
Systolic<100mmHg
Describe the 7C’s of Sepsis source identification on a surgical ward
Chest Catheter Cannula Central Line Collections Cut Calves (DVT)
What 3 situations should pain be assessed in?
In bed
Mobilising
Deep Breathing
Using the mnemonic IGRAB, state the side effects of NSAIDs
Interactions with other medications (eg Warfarin) Gastric Ulcers Renal Impairment Asthma Sensitivity Bleeding Risk (interacts with platelets)
Give an example of a weak and strong Opioid respectively
Weak - Codeine
Strong - Fentanyl
How do Opioids work as pain relief?
Work by activating the opioid receptors MOP, DOP and KOP in the CNS, modifying pain perception
Give four side effects of Opioids
Nausea
Constipation
Sedation
Respiratory Depression
What Opioid should be given in Renal Impairment?
Oxycodone or Fentanyl rather than Morphine
Give two points about co-prescribing with Opioids
- Paracetamol should be co-prescribed to reduce the requirements of opiates
- Do not co-prescribe weak and strong opioids as they competitively inhibit the same receptors
Describe the bioavailability of Morphine
Oral is 30%
SC/IV is 80%
What is Patient Controlled Analgesia?
Use of pumps that give IV bolus when patient presses a button
Analgesia is tailored to patient, and the amount they use it can be converted to a regular dose
What is Neuropathic Pain?
Irritation/Injury to nerves which present as shooting/stabbing pain
Describe the non pharmacological and pharmacological management of Neuropathic Pain
Non Pharmacological - CBT, Transcutaneous Nerve Stimulation
Pharmacological - Gabapentin, Amitryptyline, Pregabalin
Define Major Haemorrhage
Bleeding to the extent that the patient is in shock
Define Massive Haemorrhage
Loss of whole blood volume within 24 hours
How does Tranexamic Acid work?
Reduces the conversion of Plasminogen to Plasmin and hence clot break down
What is Thromboelastography?
Measures: How quickly a clot forms, how ‘strong’ the clot is, and how quickly the clot breaks down
What is the Lethal Triad of Death
Acidosis
Hypothermia
Coagulopathy
What is Cell Salvage?
Used in haemorrhages where you give the patient back their own blood
Good for Jehovah’s Witnesses
State the order of Cannulas from smallest to largest
Blue - 22G Pink - 20G Green - 18G Grey - 16G Orange - 14G
Give 6 complications of blood transfusions
ARDS O2 Affinity Abnormalities Hypothermia Electrolyte abnormalities Thrombocytopenia Acid Base Abnormalities
State four consequences of PONV
Increased recovery time
Aspiration Pneumonia
Incisional Hernia
Metabolic Alkalosis
Name one patient factor, one surgical factor and one anaesthetic factor increasing risk of PONV
Patient - Female
Surgical - Intra-abdominal Lapropscopic Surgery
Anaesthetic - Inhalation agents
What is the Vomiting Centre?
Lateral reticular formation located in Medulla Oblongata responsible for co-ordinating movements involved in vomiting
Name four inputs to the Vomiting Centre
Chemoreceptor Trigger Zone
Vestibular System
GI tract
Higher Cortical
Give an example of neurotransmitters used in : Vomiting Centre, CTZ, GI tract, Vestibular Apparatus
Vomiting Centre and Vesitibular Apparatus: Histamine
GI Tract and CTZ: Dopamine
What prophylaxis could you give a patient to try and avoid PONV?
Reduce use of volatile gases
Anti-Emetics
Dexamethasone at anaesthetic induction
The management of PONV post op should be multimodal. Give two examples of medications that could be used
Ondansetron
Cyclizine
Describe the likely aetiology of a post-op infection depending on the time frame
Day 1-2 : Resp Source
Day 3-5: Urinary Tract Source
Day 5-7: Surgical Site/Abscess
What is PUO
Pyrexia of Unknown Origin
Recurrent Fever>38 persisting for more than 3 weeks without an obvious cause despite more than a weeks worth of inpatient investigations
How should you treat a PUO with an unknown infective cause?
IV Cefuroxime, Metronidazole and Gentamicin
What is Atelectasis?
Partial collapse of the small airways
What causes Atelectasis
Thought to be a combination of airway compression, intraoperative alveolar gas resorption, and impaired surfactant production
Give four risk factors for Atelectasis
Age
Smoking
Prolonged Bed Rest
Pre-existing lung disease
How would Atelectasis present clinically?
Varying degrees of compromise but normally increased resp rate and decreased O2 sats
How is Atelectasis managed?
Deep breathing exercises
Chest Physio
If persisting - Bronchoscopy
State four O2 giving devices WITHOUT ventilatory support
Nasal Cannulae
Simple Hudson Face Mask
Venturi Face Mask
Non Rebreath Mask
Why is a Venturi Mask used for Controlled Oxygen Therapy?
Can measure the exact oxygen given
What is a physiological shunt (in terms of ventilation)?
Alveoli that are perfused but not ventilated
What is physiological dead space (in terms of ventilation)?
Alveoli that are ventilated but not perfused
What is PEEP?
Positive End Expiratory Pressure
Splints open small airways so that they don’t collapse after expiration (hence reducing physiological shunt)
What is CPAP?
Focuses on maximising PEEP by giving a continuous amount of pressure
What is BiPAP?
Respiratory support AND ventilatory support
Two different levels of CPAP (one higher during insp and one lower during exp)
Used in Type 2 Resp Failure
Name two possible harmful outcomes of artifical ventilation
Volutrauma
Barotrauma
Give three reasons why post- op patients are pre-disposed to Pneumonia
Reduced chest ventilation (stasis of fluids)
Change of Commensals (Hospital)
Intubation
What is ARDS?
Acute Respiratory Distress Syndrome
Acute lung injury characterised by severe hypoxaemia in the absence of a cardiogenic cause
Describe the four diagnostic features of ARDS
- Acute onset within 7 days
- PaO2:FiO2 is less than 300
- Bilateral infiltrates on CXR
- Alveolar Oedema not explained by cardiogenic causes or fluid overload
Give two direct and two indirect causes of ARDS
Direct - Pneumonia, Smoke Inhalation
Indirect - Sepsis, Polytrauma
Describe the pathophysiology of ARDS
- Direct injury or activation of inflammatory cascade results in breakdown of alveolar capillary barrier
- Permeability increases leading to alveolar oedema
- Reduces gas exchange and damages type II alveolar cells
How would you manage ARDS?
Resp Support (likely requiring intubation and ITU) Treat underlying cause
Describe the components of Virchow’s Triad
- Abnormal Blood Flow
- Abnormal Blood Contents
- Abnormal Vessel Wall
Give four clinical features of a DVT
Unilateral leg pain and swelling
Low grade pyrexia
Pitting Oedema
Prominent Superficial veins
How is the Wells Score used to determine further investigations in DVT?
If Wells Score<1 then a DVT is unlikely and D-Dimers should be used
If Wells Score>1 then DVT is likely and should be confirmed using USS or Contrast Venography
Describe D-Dimers in terms of Sensitivity and Specificity
High Sensitivity Low Specificity (also raised in Heart Failure, Cancer etc)
How would you manage a haemodynamically stable DVT/PE?
DOACs (Unless Renal Impairment - Warfarin)
Direct Factor Xa Inhibitor - Apixiban, Rivaroxiban
Direct Thrombin Inhibitor - Dabigatran (5 days of LMWH first)
How is the Wells Score used to determine further investigations in PE?
If Wells Score<4 then a PE is unlikely and D-Dimers should be used
If Wells Score>4 then PE is likely and should be confirmed using CTPA
Describe 3 ways a PE could present on an ECG
RBBB
RV Strain (inverted T waves in V1-V4)
S1Q3T3 - Deep S, Pathological Q, Inverted T
What is a Massive PE?
PE causing haemodynamic compromise
Requires thrombolysis
Give two examples of mechanical thromboprophylaxis
Antiembolic Stockings
Intermittent Pneumatic Compression (in theatre)
What is an Anastamotic Leak?
Leak of luminal contents from a surgical join
Name four risk factors for Anastamotic Leaks
Steroid Use
Obesity
Emergency Surgery
Longer Intraoperative Time
Give 3 clinical presentations of Anastamotic Leaks
Abdominal Pain and Fever (usually 5-7 days post-op)
Delirium
Prolonged Ileus
What technique of imaging should be used for Anastamotic Leaks?
CT with contrast
Describe three managements of Anastamotic Leaks
NBM
Broad Spectrum Abx
Percutaneous Drainage/Explorative Laparatomy
What is Post-Op Ileus?
- Deceleration/Arrest in intestinal motility following surgery
- Very common but may be a sign of a more serious pathology such as anastamotic leaks
Give four risk factors for Post-Op Ileus
Electrolyte Imbalances
Anticholinergics
Opioids
Extensive Intra-Operative bowel handling
Give three clinical features of Post-Op Ileus
- Failure to pass flatus/faeces
- Nausea/Vomiting
- Bloating
Describe the bowel sounds of Post-Op Ileus compared to Mechanical Obstruction
Post - Op Ileus = Absent
Mechanical Obstruction = Tinkling
Describe the management of Post-Op Ileus
Conservative
Daily Bloods
Encouraging mobilisation
Could drain with NG tube
Warn patients they may have watery diarrhoea for the first few days after
What are Bowel Adhesions?
Fibrous bands of scar tissue secondary to previous surgery or intra-abdominal inflammation
Most common cause of small bowel obstruction
How would you manage uncomplicated Bowel Obstruction?
Tube decompression
NBM
Analgesia
IV Fluids
How would you manage complicated (ie ischaemia, perforation) Bowel Obstruction?
Adhesiolysis (normally laproscopically)
What is an Incisional Hernia? Give 3 risk factors
Protrusion of contents of a cavity through the previously made incision in the bowel wall
Midline Incision, Pre-Op Chemo, BMI>25
Give four different aetiologies of Constipation
Physiological (eg low fibre diet)
Iatrogenic (eg Opioids)
Pathological (eg BO)
Functional (eg previously painful defaecation)
Give an example of an Osmotic, Stimulant, Bulk Forming and Rectal Laxative respectively
Osmotic - Movicol
Stimulant - Sodium Picosulfate
Bulk Forming - Ispaghula Husk
Rectal - Glycerin Suppository
Give four causes of Post-op Hypogylcaemia
- Hypoglycaemics/Insulin Overdose
- Late Gastric Dumping
- Decompensated Liver Disease
- Adrenal Insufficiency
State four clinical features of Hypoglycaemia
Sweating
Tingling Lips
Slurred Speech
Tachycardia (Beta Blockers may distort this)
How should you manage conscious patients with Hypoglycaemia?
Oral Glucose and Complex Carbohydrates
How should you manage unconscious patients with Hypoglycaemia?
O2 and IV Glucose
IV Glucose Fluid Therapy
Any delay - IM Glucagon
How is Hypoglycaemia managed intra-operatively?
BM measurements taken every 30 mins
<4mmol/l causes insulin infusion to be stopped
<2mmol/l is a hypoglycaemic emergency
Give 3 causes of post op Hyperkalaemia
Post Op AKI
Repeated Blood Transfusions
Diuretics
What other electrolyte abnormality might you have to correct along with HYPOkalaemia?
HYPOmagnesaemia
Why is Post-Op HYPOnatraemia a problem?
Most common post-op electrolyte abnormality
Can cause cellular oedema and swelling which impairs tissue healing
Why is Post-Op Hyponatraemia common?
They are likely given a lot of Dextrose Fluid intra-op
Fluid retention is part of the stress response to surgery (via increased cortisol and ADH)
Give 3 Pre-Op prophylactic measures to prevent wound infections
Prophylactic Antibiotics
Dont routinely remove hair
Maximise Diabetic control
What is Wound Dehiscence?
The wound fails to heal, reopening a few days after surgery
Most common with Abdominal Wounds
Describe the two types of Wound Dehiscence
Superficial - Skin wound alone fails, rectus sheath remains intact (often secondary to infection/DM)
Full Thickness - Rectus sheath fails to heal and bursts causing potential protrusion of abdo organs
How would you manage Superficial Wound Dehiscence?
Wash out with saline
Simple wound care
Advise patient the wound now needs to heal by secondary intention
How would you manage Full Thickness Wound Dehiscence?
Analgesia
Broad Spectrum Abx
Cover with saline gauze
Return to surgery
What are Keloid Scars?
Abnormal proliferations of scar tissue occurring at the site of injury (due to excess fibroblast activity)
Rising above the skin level
Projects beyond margins
Does not regress
Give four risk factors for Keloid Scars
Ethnicity (Black and Asian)
Age (between 20 and 30)
Cause of injury (Burns)
Anatomical Site (Ear Lobes, Shoulder, Sternum)
What is the difference between Keloid Scars and Hypertrophic Scars?
Keloid Scars proliferate outside of the wound margins whereas Hypertrophic scars remain within
Describe the management of Keloid Scars
Rarely operated on (due to recurrence)
Intralesional Steroids
Silicone Gel
Radiation Therapy
How would you classify cardiac risk pre-op?
High: >5%
Intermediate: 1-5%
Low: <1%
Increased if you are going into a body cavity
Describe the ASA from I to VI
I - Normal Healthy II - Smoker/Obese/Pregnant III - Severe systemic disease IV - Severe systemic disease with constant threat to life V - Will die without op VI - Brain dead
What is SORT?
Surgical Outcome Risk Tool
Used to stratify the risk of mortality one month after surgery etc
If more than 5% consider post-op ITU
Describe the time scale of Surgical Procedures
Urgent
Emergency
Expedited
Elective
Name a classification system for cellulitis
Enron Classification
Name two early and two late adverse transfusion reactions
Early - Anaphylaxis, Acute Haemolytic
Late - Infections, Iron Overload
How should you manage Heart Failure patients requiring transfusion?
Absolutely essential if Hb<50g/l
Transfuse with caution if Hb 60-80g/l
Give blood alongside furosemide
