Preparation for surgery Flashcards
1
Q
What is the definition and examples of ASA Grade I?
A
- Normal healthy patient
- Healthy, non-smoking, no or minimal alcohol use
2
Q
What is the definition and examples of ASA Grade II?
A
- A patient with mild systemic disease
- Mild diseases without substantive functional limitations, e.g. smoker, social alcohol drinker, pregnancy, obesity (BMI 30-40), well-controlled diabetes mellitus/ HTN, mild lung disease
3
Q
What is the definition and examples of ASA Grade III?
A
- Patient with severe systemic disease
- Substantive functional limitations; one or more moderate to severe diseases e.g. poorly controlled DM/HTN, COPD, BMI>40, active hepatitis, alcohol dependence or abuse, implanted pacemaker, moderate reduction of ejection fraction, end-stage renal disease undergoing regular dialysis, >3 months of MI history, CVAs
4
Q
What is the definition and examples of ASA Grade IV?
A
- A patient with severe systemic disease that is a constant threat to life
- e.g. recent (<3 mth) MI, CVAs, ongoing cardiac ischaemia or severe valve dysfunction, severe reduction of ejection fraction, sepsis, DIC, ARD or ESRD not undergoing regularly scheduled dialysis
5
Q
What is the definition and examples of ASA Grade V?
A
- A moribund patient who is not expected to survive without the operation
- e.g. ruptured abdominal/ thoracic aneurysm, massive trauma, intra-cranial bleed with mass effect, ischaemic bowel in face of significant cardiac pathology or multiple organ/ system dysfunction
6
Q
What is the definition and examples of ASA Grade VI?
A
- A declared brain-dead patient whose organs are being removed for donor purposes
7
Q
What are 5 available routes for establishing intravenous accessing during/before surgery?
A
- Peripheral venous cannula
- Central lines
- Intraosseous access
- Tunneled lines
- Peripherally inserted central cannula
8
Q
What are 3 advantages of peripheral venous cannulae?
A
- easy to insert
- minimal morbidity
- when properly managed, infections may be promptly identified and cannula easily re-sited
9
Q
What is the benefit of wide-lumen cannulae?
A
Can provide rapid fluid infusions
10
Q
What are 2 problems with peripheral venous cannulae?
A
- Problems relating to peripheral sites
- Unsuitable for administering vaso-active drugs such as inotropes, and irritant drugs such as TPN
11
Q
What are 3 key disadvantages of central lines?
A
- Insertion more difficult that peripheral venous cannulae
- Coagulopathies may lead to haemorrhage following iatrogenic arterial injury
- The multiple lumens are relatively narrow and don’t allow rapid rate of infusion
12
Q
What is normally done to aid the insertion of central lines?
A
most operators and NICE advocate use of ultra-sound
13
Q
What are 2 sites for central lines?
A
- Internal jugular
- Femoral lines
14
Q
What are 2 advantages and 1 disadvantage of femoral lines over internal jugular lines?
A
Pros: easier to insert, iatrogenic injuries easier to manage
Cons: Prone to high infection rates
15
Q
What is the preferred route for a central line?
A
Internal juugular route
16
Q
What is a key advantage of central lines?
A
They have multiple lumens allowing for administration of multiple infusions
17
Q
Where is intraosseous access usually performed?
A
At the anteromedial aspect of the proximal tibia
18
Q
What does intraosseous access provide access to?
A
The marrow cavity and circulatory system
19
Q
Traditionally which patients is intraosseous access performed in, and who else can it be used for?
A
Traditionally paediatrics; can also be used in adults and wide range of fluids infused
20
Q
What are 2 examples of tunneled lines for intravenous access?
A
- Hickman
- Groshong
21
Q
Among which patients are tunnelled lines popular?
A
Patients with long term therapeutic requirements
22
Q
How and where are tunnelled lines usually inserted?
A
Using ultrasound guidance, into internal jugular vein then tunnelled under the skin. Cuff of woven material sited near end, anchors device into tissues
23
Q
How can tunnelled line devices be removed?
A
Cuffs at the end require formal dissection to allow device to be removed
24
Q
What can tunneled lines for intravenous access be linked to?
A
Injection ports located under the skin
25
In which paient population are tunnelled lines particularly popular?
Paediatrics
26
What is a peripherally inserted central cannula (aka PICC line) popularly used for?
Establishing **central** venous access
27
What is the advantage of a PICC line to obtain central venous access?
They are inserted peripherally so less prone to major complications relating to device insertion than conventional central lines
28
What are the 5 cannula colours and sizes, and the maximal flow rates of each?
1. Orange 14g - 270ml/min
2. Grey 16g - 180ml/min
3. Green 18g - 80ml/min
4. Pink 20g - 54ml/min
5. Blue 22g - 33ml/min
29
What are 6 types of nutrition options in surgical patients?
1. Oral intake
2. Nasogastric feeding
3. Naso-jejunal feeding
4. Feeding jejunostomy
5. Percutaneous endoscopic gastrostomy (PEG)
6. Total parenteral nutrition
30
How can oral intake for surgical patients be supplemented?
Calorie-rich dietary supplements
31
How is naso-gastric feeding usually administered?
Via fine bore naso-gastric feeding tube
32
What are 2 key things that complications of nasogastric tubes relate to?
1. Aspiration of feed
2. Misplaced tube
33
In what group of patients may naso-gastric feeding be safe to use?
Patients with impaired swallow
34
When is naso-gastric feeding often contra-indicated and why?
Following head injury due to risks associated with tube insertion
35
What are 2 key advantages of naso-jejunal feeding?
1. Avoids problems of feed pooling in stomach (and risk of aspiration)
2. Safe to use following oesophagogastric surgery
36
What is the safest way to insert a naso-jejunal feeding tube and why?
Easiest if done **intra-operatively**, as more technically complicated than NG tube
37
What is a feeding jejunostomy?
Surgically sited feeding tube - from skin to jejunum
38
What are 2 key advantages of feeding jejunostomies?
1. May be used for long-term feeding
2. Low risk of aspiration and thus safe for long term feeding following upper GI feeding
39
What are 2 risks of feeding jejunostomies?
1. Tube displacement
2. Peritubal leakage immediately following insertion, which carries a risk of peritonitis
40
How are percutaneous endoscopic gastrostomies (PEGs) inserted?
Combined endoscopic and percutaneous tube insertion
41
In which patients may it not be possible ot insert a PEG?
Those who cannot undergo successful endoscopy
42
What are 2 risks of PEGs for feeding?
1. Aspiration
2. Leakage at the insertion site
43
For whom is total parenteral nutrition the definitive option?
Patients in whom enteral feeding is contraindicated (i.e. bypass the GI system)
44
What is needed for patients alongside total parenteral nutrition?
Individualised prescribing and monitoring
45
How should total parenteral nutrition be administered and why?
Via a central vein as it is strongly phlebitic
46
What are 2 risks associated with long term total parenteral nutrition?
1. Fatty liver
2. Deranged LFTs
47
What are 6 things to consider in elective surgical cases as preparation for surgery?
1. Consider pre-admission **clinic** to address medical issues
2. **Blood tests** including FBC, U+Es, LFTs, clotting, group and save
3. **Urinalysis**
4. **Pregnancy test**
5. **Sickle cell test**
6. **ECG/ chest x-ray**
48
What will the exact tests performed before elective surgery depend on?
The proposed procedure and patient fitness
49
What is the key thing to consider risk factors for and make a plan accordingly, prior to surgery?
Deep vein thrombosis
50
What is a risk of surgery that is increased by poorly controlled diabetes?
High risk of woud infections
51
What is the first things to do in emergency surgical cases?
Stabilise and resuscitate where needed
52
After stabilisation and resuscitation in an emergency surgical, what are the 3 things that should be done next?
1. Consider whether antibiotics are needed and when and how they should be administered
2. Inform blood bank if major procedures planned, particularly where coagulopathies are present at the outset or anticipated e.g. ruptured AAA repair
3. Don't forget to consent and inform relatives
53
What special preparation is required for thyroid surgery?
Vocal cord check
54
What special preparation is required for parathyroid surgery?
Consider methylene blue to identify gland
55
What special preparation is required for a sentinel node biopsy?
Radioactive marker/ patent blue dye
56
What special preparation is required for surgery involving the thoracic duct?
Consider administration of cream
57
What special preparation is required for phaeochromocytoma surgery?
alpha and beta blockade
58
What special preparation is required for carcinoid tumours?
Covering with octreotide
59
What special preparation is required for colorectal cases?
Bowel preparation (especially left-sided surgery)
60
What special preparation is required for thyrotoxicosis?
Lugols iodine/ medical therapy
61
What are the 3 phases of an operation identified by the WHO surgical safety checklist?
1. Before the induction of *anaesthesia* (**sign in**)
2. Before the *_incision_* of the skin (**time out**)
3. Before the patient *leaves* the operating room (**sign out**)
62
What must be performed in each 'phase' identified by the WHO surgical safety checklist?
Checklist coordinator must confirm that the surgery team has completed the listed tasks before proceeding with the operation
63
What are the 7 things that must have been checked before the induction of anaesthesia?
1. **Patient** has confirmed: site, identity, procedure, consent
2. **Site** is marked
3. **Anaesthesia** safety check completed
4. **Pulse oximeter** is on patient and functioning
5. Does the patient have a known **allergy**?
6. Is there a **difficult airway/ aspiration** risk?
7. Is there a risk of \>500ml **blood loss** (\>7ml in children)?
64
What does thermoregulation in the perioperative period refer to?
* Temperature management of patients from **1 hour prior** to their surgery until **24 hours after** the surgery has been completed
* Patient should be kept normothermic: focus on **preventing hypothermia**
65
What is the definition of hypothermia in the perioperative setting?
\<36 degrees
66
Why is thermoregulation important in the perioperative period?
Essential to ensure good outcomes, as even slight reductions in temperature can have significant effects
67
Why are patients more likely to become hypothermic whilst under anaesthesia?
1. Due to fact they can't mount normal behavioural responses to cold
2. Effects of anaesthetic drugs
3. Often wearing little clothing with large body areas exposed
68
What are 5 risk factors for peri-operative hypothermia?
1. ASA grade 2 or above
2. major surgery
3. low body weight
4. large volumes of unwarmed IV infusions
5. unwarmed blood transfusions
69
What is the pre-operative phase as defined by NICE?
1 hour before induction of anaesthesia
70
What should be done in the pre-operative phase to prevent hypothermia?
* Temperature should be measured and if lower than 36, active warming should be commenced immediately
* If temperature is equal or greater than 36, acceptable to start warming 30 minutes prior to anaesthetic induction
* Shouldn't move patient to theatre suite if \<36 unless have a time critical condition that requires urgent management
71
How should patient temperature be measured during the intra-operative phase?
* Should be conducted with direct measurement of core temperature or a direct estimate shown to be accurate to within 0.5oC
* infra-red tympanic devices should **not** be used, **axillary and sublingual devices** will be used pre-operatievly with **oesophageal probes** often used during operation for anaesthetised patients
72
What are 2 things that should be done intra-operatively to prevent hypothermia?
1. Forced air warming devices e.g. 'Bair Hugger' should be used from onset of anaesthesia, for any patient with anaesthetic duration \>30 minutes or patients at high risk
2. Fluid volumes of \>500ml and all blood products should be warmed prior to administration (- but doesn't correct existing hypothermia)
73
What is intraoperative hyp**_er_**thermia typically due to?
Over-warming rather than fever (both volatile agents and opioids used for anaesthesia blunt febrile response)
74
What should be done for temperature regulation during the post-operative phase?
* Following transfer to the recover room, temperature should be documented initially then repeated every 15 minutes until transfer to the ward
* shouldn't be transferred to ward if temperature \<36
75
Why are patients more likely to display hyp**_er_**thermia in the post-operative phase than the peri-operative phase?
Due to fever response in the post-operative phase because of anaesthetic drugs being eliminated from circulation
76
What are 5 complications of perioperative hypothermia?
1. **Coagulopathy**: reduces blood's ability to clot, increased blood loss during surgery
2. **Prolonged recovery from anaesthesia**: prolongation of anaesthetic agents - muscle relaxants, propofol and inhalational agents
3. **Reduced wound healing**: local vasoconstriction so reduced perfusion to skin, reduces necessary immune moderators available at site
4. **Infection**: combination of poorer incisional site healing and reduced number of immune cells able to access skin
5. **Shivering**: can cause significant increase in metabolic rate, in some patient groups can result in myocardial ischaemia
77
What are 15 risk factors for deep vein prophylaxis in surgical patients?
1. Surgery lasting \>90min, or \>60min in lower limbs or pelvis
2. Acute admissions with inflammatory process involving abdominal cavity
3. Expected significant reduction in mobility
4. Age over 60 years
5. Known malignancy/ chemotherapy
6. Thrombophilia/ clotting disorder
7. Previous thrombosis
8. BMI \>30
9. Taking hormone replacement therapy or contraceptive pill
10. Varicose veins with phlebitis
11. Dehydration
12. one or more significant medical comorbidities e.g. heart disease, respiratory disease
13. Critical care admission
14. Pregnant or less than 6 weeks post-partum
78
What are 4 forms of mechanical thromboprophylacis?
1. Early ambulation after surgery - cheap and effective
2. Compression stockings (CI in peripheral arterial disease)
3. Intermittent pneumatic compression devies
4. Foot impulse devices
79
What are 4 types of therapeutic agents for thromboprophylaxis for surgery?
1. Low molecular weight heparin
2. Fondaparinux (SC injection)
3. Unfractionated heparin
4. Dabigatran
80
What is the method of action of low molecular weigth heparin?
Binds antithrombin resulting in inhibition of factor Xa
81
What are 2 examples of LMWH?
* Enoxaparin aka Clexane
* Dalteparin
82
What is the mechanism of action of unfractionated heparin?
Binds antithrombin III which affects thrombin and factor Xa
83
What is the mechanism of action of dabigatran?
Orally administered direct thrombin inhibitor
84
How is low molecular weight heparin administered?
Given once daily as subcutaneous injection
85
In what risk category of DVT is LMWH given?
_Low_ doses given in those with **moderate to high** risk of thromboembolic events (if patients have normal renal function)
86
How is unfractionated heparin administered?
Intravenously
87
What is the onset and duration of action of unfractionated heparin?
Rapid onset, therapeutic effects decline quickly on stopping infusion
88
How is the activity of unfractionated heparin monitored?
Using APTT (activated partial thromboplastin time)
89
What can be used to reverse unfractionated heparin?
Protamine sulphate
90
When is dabigatran used as thromboprophylaxis?
Hip and knee surgery
91
Does dabigatran reuire therapeutic monitoring and is there an antidote?
No and no
92
In which patients should dabigatran not be used?
Any patient in whom there is a risk of active bleeding, or imminent likelihood of surgery
93
When is VTE risk assessment performed?
All patients admitted to hospital should be individually assessed to identify risk factors for VTE developement and bleeding risk
94
What is the recommended VTE risk proforma for medical and surgical patients?
Department of Health's VTE risk assessment tool
95
What key factor deems a medical patient at increased risk of developing VTE?
Significant reduction in mobility for 3 days or more (or anticipated to have significantly reduced mobility)
96
What are 6 risk factors for VTE specific to surgical/trauma patients?
1. hip/knee replacement
2. hip fracture
3. general anaesthetic and surgical duraction \>90min
4. surgery of pelvis or lower limb with GA and \>60min
5. acute surgical admission with inflammatory/intra-abdo condition
6. surgery with signficant reduction in mobility
97
In which patients is unfractionated heparin used for thromboprophylaxis?
patients with chronic kidney disease
98
What is the exception to starting patients at risk of VTE on pharmacological VTE prophylaxis?
Providing risk of VTE outweighs risk of bleeding, and no contraindications
99
What thromboprophylaxis may be given to medical patients at VERY high risk?
Anti-embolic stockings alongside pharmacological methods
100
What is the first line treatment for surgical patients at LOW risk of VTE?
Anti-embolism stockings
101
What thromboprophylaxis is given to surgical patients at HIGH risk?
Stockings and pharmacological
102
What pre-surgical advice for thromboprophylaxis is given to patients?
Advise women to stop taking combined oral contraceptive pill/hormone replacement therapy **4 weeks** before surgery
103
What are 2 post-surgical interventions for thromboprophylaxis?
1. Mobilise patients as soon as possible after surgery
2. Ensure patient is hydrated
104
What are three options for thromboprophylaxis following an elective hip replacement?
1. LMWH for 10 days followed by aspirin (75 or 150mg) for a further 28 days
2. LMWH for 28 days combined with anti-embolism stockings until discharge
3. Rivaroxaban
105
What are 3 thromboprophylaxis options following elective knee surgery?
1. aspirin 75 or 150mg for 14 days
2. LMWH for 14 days combined with anti-embolism stockings until discharge
3. rivaroxoban
106
What 2 options for thromboprophylaxis are recommended by NICE following fragility **fractures** of the pelvis, hip and proximal femur?
Prophylaxis for a month (if low bleeding risk), either:
1. **LMWH**, startign 6-12 hours after surgery
2. **Fondaparinux**, starting 6hrs after surgery
