21 - Perioperative Care 2 (OSCE Practice) Flashcards
What is the definition of an AKI and how is it staged?
Any of the following:
- 50% rise in creatinine from baseline in the past 7 days
- Increase in serum creatinine by >26.5mmol/L within 48 hours
- Urine output <0.5mls/kg/hr for more than 6 hours
Staging is to do with serum creatinine
What are some of the causes of an AKI?
- Prerenal: sepsis, dehydration( e.g NBM/bowel preparation), haemorraghe, renal artery stenosis
- Renal: nephrotoxins (e.g NSAIDs, ACEi, ARBs, Abx or Chemotherapy Cisplastin), parenchymal disease like glomerulonephritis, rhabdomyolysis, HUS
- Post-renal: renal stones, retroperitoneal fibrosis of ureter, blocked catheter, acute urinary retention, prostatic enlargement
How can you investigate an AKI?
- Assess fluid status of patient
- Bladder scan to see if retention
- Review drug chart for nephrotoxic drugs
- Urine dip
- FBC, CRP, LFTs, Ca
- ABG
- US KUB if not responding to initial treatment to look for obstructive pathology and any hydronephrosis
How is an AKI managed as this is classed as a medical emergency?
TREAT UNDERLYING CAUSE
Fluid status: Assess patient’s hydration status. If pre-renal cause suspected give fluid bolus, reassess and monitor urine output. Repeat boluses until euvolemic
Ongoing monitoring: Monitor urine output and consider catheter. Regular bloods with U+Es to check creatinine. If not responding to fluid therapy consider intrinsic and post renal causes
Drug Rationalisation: see image
What are the clinical features of acute urinary retention (symptomatic inability to empty bladder) in surgical patients?
- Little to no urine passed
- Sensation of needing to void but cannot
- Suprapubic mass that is dull to percuss
What are some common causes of acute urinary retention in the post surgical patient?
- Poor pain control
- Constipation
- Infection
- Anaesthetic agents (spinal or epidural use)
What are some risk factors for post operative urinary retention?
- >50
- Male
- Previous retention
- Pelvic or urological surgery
- Spinal or epidural anaesthesia
- Neurological or urological comorbities
- Antimuscarinics, alpha agonists, opiates
How do you assess a surgical patient with acute urinary retention?
- US bladder scan to look at post-void residual urine volume
- Check for any underlying reversible causes
- Adequate pain control
- Check renal function with U+Es
What is the management for acute urinary retention?
- Catheterisation
- TWOC (trial w/o catheter) shortly after
- If failed TWOC recatheterise then repeat TWOC in 1-2 weeks
What are the common organisms that cause UTIs in surgical patients?
- E.coli
- Klebsiella Sp
- Enterobacteur Sp
- Proteus Sp
- Pseudomonas Sp
- Staphylococcus Sp
What are some risk factors for developing a UTI post operatively?
- Femal
- Aged >60
- Significant comorbidities e.g DM
- Catheterisation
- Pregnancy
- Urinary retention
- Renal stones
How may a surgical patient with a UTI present?
- Dysuria, frequency, urgency
- May have suprapubic pain and pyrexia
Also check for signs of pyelonephritis!!! (loin pain, pyrexia, renal angle tenderness)
How should you investigate a suspected UTI in a surgical patient?
- Urine dipstick (nitrites or leucocyte esterase or blood +)
- MSU/CSU for MC&S
- Routine bloods (FBC, U+Es, CRP)
- Blood cultures and VBG if systemically unwell/sepsis
- If entered retention then bladder scan
- If pyelonephritis suspected then US to look for obstruction
What type of bacteria will cause nitrites to be positive on a urine dipstick?
Gram -ve as they can convert nitrates in the urine into nitrites
How should we manage surgical patients with a UTI?
- Ensure patient well hydrated
- Ensure patient has urine output >0.5mls/kg/hr
- Start abx (trimethoprim, nitrofurantoin or co-amoxiclav)
- Change any catheters before starting abx
What are some risk factors for developing hypoglycaemia post surgically?
- Diabetes
- Post gastrectomy or gastric bypass
- Alcohol excess
- Renal dialysis
- Beta blockers
What are the clinical features of hypoglycaemia?
- Sweating
- Tingling lips or extremities
- Dizziness
- Slurred speech
- Signs of pallor, confusion, tachycardia, tachypnoe
If taking beta blockers will mask signs and symptoms of hypoglycaemia as symptoms mediated by sympathetic nervous symptoms
What is gastric dumping syndrome?
Complication of gastric bypass surgery
Early (10-30 minutes post prandial): sudden large passage of hypertonic gastric contents into small intestine so intraluminal fluid shift and intestinal distension. Causes n+v, diarrhoea and hypovolemia
Late (1-3 hours post prandial): surge in insulin production following dumping of food leads to hypoglycaemia
How is gastric dumping syndrome managed?
- Small frequent meals
- Avoidance of simple carbohydrates
- Separation of eating and drinking to avoid heavy loads on stomach
- Refer to dietician
How is hypoglycaemia managed after a BM and serum blood glucose is taken?
- A to E
- Conscious patient: Oral glucose immediately e.g 10g Glucogel. Monitor BM every 1-2 hours.
If no improvement start IV 1L 10% dextrose over 8 hours and monitor BMs
- Unconscious patient: Protect airflow and give high flow oxygen. Get IV access and give IV glucose (100ml 20% dextrose). If cannot get IV then intramuscular glucagon
How often is blood glucose monitored intraoperatively in diabetics?
- Every 30 minutes in diabetic patients
- If <4mmol diabetic on IVVRI then increase glucose infusion and stop insulin and recheck after 30 minutes
- If <2mmol treat as hypoglycaemia emergency
What is the definition of hyperkalaemia and what are some causes of this in the post operative patient?
K>5.5mmol/L
- Post op AKI
- Repeated blood transufsions
- Drugs (K+ Sparing Diuretics like Spironolactone and ACEi)
- Excessive potassium treatment
How can hyperkalaemia present?
- Often asymptomatic until 7.0 mmol/L then
- Paraesthesia
- Muscle weakness
- N+V
- Palpitations
What investigations should you do if a patient has hyperkalaemia?
- Routine bloods (U+Es, Ca, PO4, Mg)
- VBG for instant K+
- ECG
- Catheterisation if for fluid balance monitoring
Look at patients obs, fluid status and drugs!!
What are some ECG changes in hyperkalemia?
Mild (5.5-6.5)
- Tall tented T’s
- Prolonged PR
Moderate (6.5-7.5)
- Flattened P wave
- Prolonged QRS
Severe (>7.5)
- Widening of QRS
- Axial deviation and bundle branch blocks
- Sine wave when T merges with QRS then subsequent AF or asystole
How is hyperkalaemia managed?
- Stabilise myocardium: calcium gluconate or calcium chloride when ECG changes present
- Reduce serum potassium: variable rate insulin with dextrose infusion to increase cellular uptake. can also give salbutamol nebulisers as only short term
- Reduce total body potassium: calcium resonium and manage underlying cause
- Continue cardiac monitoring and retake bloods
What is the definition of hypokalaemia and what are the different severities of it?
K <3.5 mmol/L
Mild: 3.1-3.5
Moderate: 2.5-3.0
Severe: <2.5
Increases risk of cardiac arrhythmias
What are some causes of hypokalaemia in the surgical patient?
- Gastrointestinal losses: vomiting, diarrhoea, laxative abuse
- Urinary losses: diuretics (thiazides, loops), minercorticoid excess (Conn’s and Cushing’s), hypomagnesaemia, polyuria, renal tubular acidosis
- Skin losses: burns, excess sweating
- Inadequate intake: malnutrition and NBM
- Intracellular shifts: alkalosis, excess insulin administration (increased Na/K pump action), excessive beta agonist activity (e.g salbutamol as increase Na/K pump)
How can hypokalaemia present?
- Usually asymptomatic but can have…
- Muscle weakness
- Paraesthesia
- Ileus or Pseudo-obstruction
- Hypotonia
- Hyporeflexia
- Muscle cramps and tetany
- Cardiac arrhythmias
What are some ECG changes in hypokalaemia?
Causes cardiac hyperexcitability so can lead to function re-entrant loops so arrhythmias can develop
- Elongated PR interval
- T wave flattening or inversion
- Prominent U wave
- ST segment depression
How do you investigate a patient with hypokalaemia?
- ECG: if any changes noted may want to put on cardiac monitor
- Bloods: FBC, U+Es, Mg, Ca, PO4
- VBG: can be used to check if interventions are working and raising potassium levels
What are the most common causes of hypokalaemia?
- Diuretic use
- Diarrhoea
- Vomiting
How is hypokalaemia treated?
- Manage underlying cause
- Mild cases with no ECG changes: oral supplements like SandoK
- Moderate to Severe with ongoing losses or with ECG changes: IV replacement (max is 10mmol/hr if need more then need central line and admission to monitored bed)
Monitor bloods daily and correct any hypomagnesiumaemia
What is the definition of hypernatraemia and what are some symptoms of this?
Na > 145 but asymptomatic until >160
- Excessive thirst
- Weakness
- Lethargy
- Irritability
- Confusion, coma and seizures
- If >180 then neurological defects appear including ataxia, tremor, coma, seizures
What are some of the causes of hypernatraemia?
Hypovolaemic Hypernatraemia: loop diuretics, dehydration/fluid restriction, acute tubular necrosis, hyperosmolar states
Euvolaemic Hypernatraemia: diabetes insipidus
Hypervolaemic Hypernatraemia: excessive hypertonic saline administration, steroid excess (Cushing’s and Conn’s)
How is hypernatraemia investigated?
- Metabolic blood panel (glucose, K, Cl, Urea, Cr)
- Blood gas for acid-base distrubance
- Urine osmolality (minimal urine with high osmolality)
- Possible ADH levels and/or CT head to assess pituitary gland if think DI
What are the different types of diabetes insipidus and how is it diagnosed?
- Cranial: impaired ADH secretion from posterior pituitary, often after pituitary surgery or head trauma
- Nephrogenic: impaired response of kidney tubules to ADH
- Present with polyuria and polydipsia. Do water deprivation test, no fluids for 8 hours then give desmopressin
How do you manage hypernatraemia?
(use mneumonic)
- Replace any fluid deficit, enteral free water preferred
- If enteral not possible give IV 5% dextrose preferred.
- Only reduce slowly by 10mmol/day as risk of cerebral oedema
What are some causes of hypo-osmotic hyponatraemia?
- Classify in terms of patients extracellular fluid status and urine sodium concentration
- Measure serum osmolality to see if hyper,hypo or isoosmotic hyponatraemia
What are some clinical features of hyponatraemia?
- Usually asymptomatic
- If severe can have neurological signs like malaise, headache, confusion, reduced consciousness, seizures
What is an issue when correcting chronic hyponatraemia that you need to be aware of?
If corrected too rapidly can cause central pontine myelinolysis
Large change in extracellular osmolarity causes damge to myelin sheaths of nerves of the brainstem
Causes confusion, balance problems then pseudobulbar palso and quadriplegia
Diagnosed by MRI, no curative treatment
What are the two types of wound dehiscence?
Most common in abdominal surgery
Superficial: skin wound alone fails to heal, rectus sheath in tact, often due to local infection, poorly controlled DM or poor nutritional status
Full Thickness: rectus sheath fails to heal and bursts out abdominal contents, often due to increased intraabdominal pressure (e.g ileus), poor surgical/suture technique or critically unwell patient
What are some risk factors for wound dehiscence after surgery? (3 of each type)
- Patient factors
- Intraoperative factors
- Post operative factors
What is a sign of full thickness/deep wound dehiscence?
New bulging of the wound with seepage of pink serous or blood stained fluid from the wound
Sudden increase in wound discharge consider this
Need to remove skin clips/sutures at area of maximal leakage and physically examine rectus sheath to see if intact
How do you manage surgical wound dehiscence?
- Take wound swabs if infection
- Superficial: wash out wound with saline then pack wound with absorbent gauze, now healing will be by secondary intention. Can do Vacuum-Assisted closure to speed things up
- Full Thickness: analgesia and broad spectrum abx. Cover wound in saline soaked gauze and arrange theatre urgently to reclose wound with large interrupted sutures
What is the pathophysiology of keloid scarring?
- Nomal wound healing there is balance between new tissue biosynthesis and tissue degradation
- In keloid scars there is prolonged inflammatory phase (immune cells get into scar rissue) so excess fibroblast activity and increased ECM deposition. Leads to tissue beyond original wound margin
What are some risk factors for keloid formation?
Keloids often shiny and hairless that start red then go pale
What is the Vancouver Scar Scale?
Way of quantifying scars and monitoring effectiveness of treatment
What are the differences between hypertrophic and keloid scars?
Once a patient has been admitted to an acute surgical ward after being stabilised using A to E, how do you investigate and manage them?
SYSTEM OF FIVE - inform the registrar
- Blood tests include FBC, U+Es, LFTs, Amylase, Clotting profile and G+S
- Imaging includes CXR and ECG
- Specialist tests could be endoscopy, CT etc
What is SBAR?
Way to hand over to senior member of staff, write down on piece of paper!!!
S: who you and the patient is and their NEWS score
B: why patient in hospital and what has changed
A: what i think it is and what i have done
R: what i would like and what would the reg like me to do
What is the A to E assessment?
- Used for critically ill patients with reduced GCS
- ALWAYS REASSESS
Report on this x-ray and state what further investigations you would request?
- FBC and CRP
- Blood culture
- Sputum for gram stain and culture
- Oxygen saturation
How do you treat post-surgical hospital acquired pneumonia and what are the likely causative organisms?
- Give co-amoxiclav if known not to be MRSA carrier as covers S.Pneumoniae and H.Influenza
- Review abx when sputum/blood culture comes back
- Have physiotherapy as may be some atelectasis
What is the likely causes of distension?
- SBO
- Ascites
An AXR for a patient shows this (see image). A CT abdomen pelvis with IV contrast is requested, what abnormalities will this show?
- presence or absence of small bowel dilatation
- the point of obstruction
- presence of ascites
- evidence of metastatic disease in other organs such as the liver)
COMMENT ON EVERYTHING WHEN REPORTING AN XRAY E.G CENTRAL LOCATION
What are the following blood products used for:
- FFP
- Cryoprecipitate
- PCC
- Platelets
What factors have contributred to this presentation?
Oesophageal varices due to portal HTN
How do you manage a patient with delirium?
How do you treat a hypertensive emergency?
- IV Labetalol
- IV sodium nitroprusside
- GTN
- Nicardipine
Lower sys BP<110 in 3-12 hours
