Download Question 2 : FT

Case 413: Anaesthetics and ICU SAQs
Authors and Affiliations
Hannah Pham
Faculty of Medicine
University of Adelaide
Dr Mark Plummer, MBBS
Research Fellow
Discipline of Acute Care Medicine
University of AdelaideThese questions are designed for those preparing for Final Year Examinations.
Case Overview
Learning Objectives
Question 1 : FT
Question Information:
A 16-year-old girl presents to the Emergency Department with a 12 hour history of abdominal pain and
vomiting and a four day history of loose bowel motions. She has a background history of type 1
diabetes mellitus. She deliberately omitted her insulin yesterday given her poor oral intake to avoid
hypoglycaemia.
On examination, her pulse rate is 110/min, blood pressure 90/50mmHg, respiratory rate 15/min, and
temperature 38.5C. She is saturating at 100% on 4 litres of oxygen. Her chest is clear, heart sounds are
dual, and there are no murmurs. Her abdomen is soft but diffusely tender to palpate. Her peripheral and
cranial nerve examinations are unremarkable. Her mucous membranes are dry.
Investigations show:
†¢ Blood glucose level (BGL) 35.5mmol/L
†¢ Urinary ketones ++
†¢ Haemoglobin 135g/L [115-155]
†¢ White cell count 12.0 x 10^9/L [4.0-10.0]
†¢ Sodium 138.0mmol/L (corrected for BGL) [137-145]
†¢ Potassium 6.0mmol/L [3.5-4.9]
†¢ Venous blood gas - pH 7.2 [7.31-7.41], HCO3mEq/L 12 [22-27], VpCO2 20mmHg [40-52]
†¢ Electrocardiogram shows normal sinus rhythm and no acute changes
†¢ Chest X-ray is unremarkable
†¢ Blood cultures and urine cultures are pending
She is given boluses of fluid and insulin.
Her repeat blood tests at one hour show a potassium of 3.2mmol/L and sodium of 135mmol/L.
Question:
What is the most appropriate fluid regimen (with/without additives) now? (1 mark) Justify your answer.
(2 marks)
Choice 1: null Score : 0
Choice Feedback:
Answer
Normal saline (0.5) with potassium replacement (0.5)
Justification
†¢ The patient is currently in diabetic ketoacidosis (DKA) precipitated by an omitted insulin dose in the
setting of an intercurrent illness (likely gastroenteritis). (0.5) She appears to be fluid deplete (supported
by the history of poor oral intake, and clinical findings of hypotension, tachycardia, and dry mucous
membranes). Fluid resuscitation is a critical part of DKA treatment.
†¢ The initial correction of fluid loss is with normal saline or lactate Ringer solution (Hartmann†™s).
When BGLs fall below 12-15mmol/L, it may be appropriate to use 5% dextrose with normal saline and
potassium. The aim should be to keep BGL between 5-12mmol/L.
†¢ She did not receive any potassium replacement initially given her potassium level was greater than
5.5mmol/L. However, rapid correction may result in hypokalaemia following insulin therapy in the setting
of acidosis. Although the initial potassium was elevated, the patient likely had a total body potassium
deficit. (1)
Notes
†¢ She should continue to have her electrolytes checked.
References
†¢ http://emedicine.medscape.com/article/118361-treatment#a1156
†¢ http://www.rch.org.au/clinicalguide/guideline_index/Diabetes_Mellitus/
Question 2 : FT
Question Information:
A 50-year-old woman is reviewed on the morning surgical ward round. She is day 3 post bowel
resection with end-end anastomosis and ileocolic resection. Post-operatively, she was febrile
(temperature 38.6C) and hypotensive (blood pressure 90/50mmHg) and received two days of
intravenous antibiotics and fluid therapy for presumed sepsis.
Today, she is feeling better. On examination her pulse rate is 90/min, blood pressure 110/70mmHg,
respiratory rate 18/min, and temperature 37.0C. She is well-perfused peripherally. Her chest is clear.
Her abdomen is soft but mildly tender over the midline wound. There is no ooze from the wound or
surrounding erythaema. She weighs 70kg.
Her current medications includes:
†¢ Gentamicin 350mg daily
†¢ Amoxicillin 2gm daily
†¢ Metronidazole 500mg bd
Her morning blood tests show:
†¢ Haemoglobin 99g/L [115-155]
†¢ White cell count 20.5x10^9/L [4.0-10.0]
†¢ Creatinine 180umol/L [53-115]
Specific drug levels were not performed.
Question:
What modification should be made to her antibiotics? (1 mark) Justify your answer. (1 mark)
Choice 1: null Score : 0
Choice Feedback:
Answer
Reduce the dose of gentamicin (1)
Justification
†¢ The patient is on gentamicin, an aminoglycoside, that was dosed according to weight at 5mg/kg. In
view of the high creatinine, however, this dose should be reduced as aminoglycosides are nephrotoxic.
(1)
Notes
†¢ Gentamicin should always be modified according to degree of renal impairment to prevent its side
effects. This is calculated as creatinine clearance using the Cockcroft-Gault formula.
†¢ Serum creatinine should be monitored at baseline and repeated every 1-3 days.
Question 3 : FT
Question Information:
A 65-year-old woman is day 6 post coiling of left anterior choroidal artery aneurysm following a
hypertensive subarachnoid haemorrhage. On presentation, her glasgow coma score was 6 with
improvement to 12 after surgical intervention. She has been extubated.
Enteral feeding (gastric) via 12Fr nasogastric tube was commenced on day 3 at a rate of 30mL/hr. On
the morning ward round, the nurse tells you that the patient†™s nasogastric aspirates have been high.
You suspect this is due to poor gastric motility. The head of the bed is elevated to 45 degrees.
Question:
In addition to this, what medication(s) should be prescribed to promote gastric emptying? (1 mark)
Justify your answer. (1 mark)
Choice 1: null Score : 0
Choice Feedback:
Answer
Erythromycin (1)
Justification
†¢ Erythromycin is a prokinetic agent (0.5) that promotes gastric emptying decreasing the risk of
aspiration from reflux. (0.5)
Notes
†¢ Checking of gastric residual volumes in asymptomatic patients receiving tube feeds is falling out of
favour. Residuals are measured if the patient condition changes, such as new-onset abdominal pain,
abdominal distension, or haemodynamic deterioration.
†¢ Metoclopramide, usually prescribed with erythromycin, should not be used in patients with head
injuries.
Question 4 : FT
Question Information:
A 67-year-old woman is admitted for a right hemicolectomy with stoma formation for adenocarcinoma of
the hepatic flexure.
She is admitted to the high dependency unit post-operatively given her extensive cardiac history, which
includes an abdominal aneurysm repair, atrial fibrillation (on warfarin, which was ceased preoperatively), non-ST elevation myocardial infarctiion, and left-sided carotid artery stenosis (80%
stenosis) with a history of multiple transient ischaemic attacks.
On day 3 post-op, she develops an ileus. This does not resolve despite conservative measures over
five days. Thus she is started on total parenteral nutrition, which she remains on for five days.
On day 14 of her admission, she suddenly goes into rapid atrial fibrillation (AF) with a pulse rate of
180/min.
Her electrolytes are as follows:
†¢ Potassium 3.0mmol/L [3.5-4.9]
†¢ Chloride 90mmol/L [100-109]
†¢ Sodium 135mmol/L [137-145]
†¢ Magnesium 0.5mmol/L [0.75-0.95]
†¢ Phosphate 0.5mmol/L [0.8-1.4]
†¢ Blood glucose level 10.5mmol/L
Question:
What is the most likely explanation for her rapid atrial fibrillation? (1 mark) Justify your answer. (1 mark)
Choice 1: null Score : 0
Choice Feedback:
Answer
Electrolyte disturbances due to total parenteral nutrition (TPN) (1)
Justification
†¢ The electrolyte disturbances are hypokalaemia, hypomagnesaemia, and hypophosphataemia,
which are classically seen in TPN (0.5) and can predispose to arrhythmias. (0.5)
Notes
†¢ Other complications of TPN to consider include hyperosmolar dehydration syndrome, glucose
intolerance (hyperglycaemia, glycosuria), refeeding syndrome, Wernicke†™s encephalopathy, hepatic
dysfunction, and macro or micro nutrient excess or deficiency.
References
†¢ UpToDate article †œNutrition support in critically ill patients: Parenteral nutrition†•
Question 5 : FT
Question Information:
A 55-year-old man is admitted to the intensive care unit for monitoring following a code blue for status
epilepticus.
He has a past history of emphysema and gout.
A subclavian central venous catheter is inserted. Several minutes later, his respiratory rate increases
from 14/min to 30/min and he complains of difficulty breathing associated with chest pain.
Question:
What is the most likely cause of his dyspnoea? (1 mark)
Choice 1: null Score : 0
Choice Feedback:
Answer
Pneumothorax (1)
Notes
†¢ A traumatic pneumothorax is a possible complication of subclavian central venous catheter (CVC)
insertion, although uncommon (1.5-3.1%). The line is placed using the anatomical landmark 1cm
inferior to the junction of the middle and medial third of the clavicle.
†¢ A chest X-ray is always performed following CVC insertion to check for correct placement.
†¢ He also has a history of emphysema, which is a risk factor for pneumothorax.
References
†¢ http://emedicine.medscape.com/article/80336-overview#a17
Question 6 : FT
Question Information:
A 35-year-old man who works as a plastic textiles worker is brought in via ambulance following a factory
chemical explosion. He is assessed in the resuscitation bay and deemed to have burns to 28% of his
total body surface area. He weighs 80kg. His complete blood exam and biochemistry are unremarkable.
Question:
Outline the fluid regimen that is most appropriate in the first 48 hours. (2 marks)
Choice 1: null Score : 0
Choice Feedback:
Answer
†¢ 28x80x4 = approximately 9 litres in the first 24 hours = approximately 4.5 litres in the first 8 hours,
4.5 litres in next 16 hours of Hartmann†™s. (0.5)
†¢ 28x80x0.5 = 1120mL in the next 24 hours of Albumin. (0.5)
†¢ Titrate the fluid regimen to a urine output of 0.5-1mL/kg/hour. (1)
References
†¢ RAH ICU Medical Manual
Question 7 : FT
Question Information:
A 40-year-old man presents with severe epigastric pain radiating to his back. A CT abdomen is
performed which shows haemorrhagic and necrotic pancreatitis. He is managed in the intensive care
unit with conservative measures. He is currently day 3. On examination, there are several small
petechiae over his body.
He has no other medical conditions of note. His current medications include enoxaparin, pantoprazole,
ketamine, and fentanyl patient controlled analgesia.
His blood tests show:
†¢ Haemoglobin 97g/L [115-155]
†¢ Platelets 80 x10^9/L [150-450]
†¢ aPTT 60 seconds [24-38]
†¢ INR 2.4 [0.9-1.2]
†¢ Fibrinogen 110mg/dL [150-400]
†¢ D-dimer 1.5 mcg/mL [Normal, less than 0.5]
†¢ Fibrin degradation products (FDP) 28mcg/mL [Normal, less than 10]
Question:
What diagnosis should be considered in this man? (1 mark). Justify your answer. (2 marks)
Choice 1: null Score : 0
Choice Feedback:
Answer
Disseminated intravascular coagulopathy (DIC) (1)
Justification
†¢ This man has severe pancreatitis that has instigated a disseminated intravascular coagulopathy
(1) This results in intravascular clot formation and severe bleeding, the latter which occurs due to
accelerated fibrinolysis. This is supported by prolonged prothrombin time, elevated INR, aPTT, and low
fibrinogen (which occurs due to consumption). We would expect fibrin degradation products to also be
elevated. (1)Notes†¢ DIC is life-threatening and can result in multiple organ dysfunction syndrome.
Therefore, it should be treated promptly. †¢ General principles of treatment include resolving the
underlying cause, monitoring of vital signs, correcting hypovolaemia, assessing and documenting extent
of haemorrhage and thrombosis, and providing haemostasis when indicated. Fresh frozen plasma,
cryoprecipitate, heparin, and fibrinolytics may be considered.
References
†¢ http://emedicine.medscape.com/article/199627-treatment
Question 8 : FT
Question Information:
A 70-year-old woman presents to the emergency department following a conscious collapse, which was
preceded by two days of severe generalised abdominal pain and vomiting. She undergoes an
exploratory laparotomy where ischaemic bowel is identified but was deemed viable and was
subsequently not resected. She is currently day 3 post-op. A nasogastric tube was placed postoperatively.
On examination today, her pulse rate is 100/min, blood pressure 90/60mmHg, respiratory rate 18/min,
and temperature 38.8C. The JVP is not elevated. There is pitting oedema up to her knees. Her chest is
clear on auscultation. Her peripheries are warm.
Her blood tests show:
Haemglobin
White
90g/L [115-155]
cell count 20.5x10^9/L [4.0-10.0]
C-reactive
Lactate
protein 150mg/dL [Normal, less than 12]
4mmol/L [0.5-1]
Question:
What is the most likely diagnosis? (1 mark) Justify your answer. (2 marks)
Choice 1: null Score : 0
Choice Feedback:
Answer
Sepsis (1)
Justification
†¢ The patient meets the criteria for systemic inflammatory response syndrome (SIRS) (1) and has a
suspected infection, likely from her ischemic bowel. (1) This therefore makes sepsis the most likely
diagnosis.
The diagnostic criteria for SIRS is:
1. Temperature >38.0C or <36.0C
2. Heart rate >90/min
3. Respiratory rate >20/min or PaCO2 <32mmHg
4. White cell count >12.0 x10^9/L or <4.0 x10^9/L or >10% immature (band) forms
Notes
†¢ This is distinguished from severe sepsis (which is sepsis with signs of end organ damage,
hypotension, or elevated lactate) and septic shock (which is severe sepsis with persistent hypotension,
signs of end organ damage, or elevated lactate).
†¢ A septic work-up, including chest X-ray, blood cultures, and urine cultures would be appropriate to
perform.
References
†¢ http://emedicine.medscape.com/article/168943-overview
Question 9 : FT
Question Information:
A 68-year-old woman is admitted to hospital for an elective radical hysterectomy and bilateral salpingooophorectomy for endometrial cancer.
She has a background history of moderate congestive cardiac failure. A transesophageal
echocardiogram two months ago demonstrated an ejection fraction of 30%. Her regular medications
includes metoprolol 50mg and frusemide 20mg daily.
On examination today, her pulse rate is 80/min, blood pressure 100/70mmHg, respiratory rate 20/min
and temperature 36.5C. Her JVP is 2cm. The chest is clear on auscultation and there is no peripheral
oedema.
Her haemoglobin today is 69g/L [115-155]. A pre-operative haemoglobin was 98g/L [115-155].
She is given two units of red blood cells. One hour following the completion of the transfusion, she
becomes mildly dyspnoeic with a respiratory rate of 24/min. Her oxygen saturation is 97% on room air.
Her blood pressure and pulse rate remain stable.
Question:
What is the most likely cause of her dyspnoea? (1 mark) Justify your answer. (2 marks)
Choice 1: null Score : 0
Choice Feedback:
Answer
Exacerbation of cardiac failure or fluid overload (1)
Justification
†¢ Two units of red blood cells is approximately 600mL of fluid, which is enough to precipitate acute
pulmonary oedema in someone with known systolic dysfunction (ejection fraction is 30% in this patient).
(1)
†¢ The main differential in this case is transfusion-associated acute lung injury (TRALI), which would
be expected to cause a more pronounced respiratory failure. (1) TRALI may occur up to six hours
following the transfusion.
Question 10 : FT
Question Information:
A 16-year-old boy arrives by transfer from a rural to a tertiary hospital six hours after a snake bite on his
lower leg. He identified it as a brown snake. A pressure immobilisation bandage was applied
immediately and remains on the lower leg. The wound site has been swabbed and blood is taken for
analysis. Anti-venom is administered.
On examination, his pulse rate is 80/min, blood pressure 120/70mmHg, respiratory rate 14/min, and
temperature 36.2C. Two small bite marks 0.5cm apart are seen just above his left lateral malleolus.
There is mild erythema at the site. There is no surrounding swelling or bruising.
His blood tests show a normal complete blood examination and coagulation studies. His serum
creatinine is 300umol/L [53-115] and Creatine kinase (CK) is 1200IU/L [60-174].
An electrocardiogram shows normal sinus rhythm. His urine output is approximately 20mL/hr.
Question:
What is the most likely diagnosis? (1 mark) Justify your answer. (2 marks)
Choice 1: null Score : 0
Choice Feedback:
Answer
Rhabdomyolysis (0.5) and acute kidney injury (0.5)
Justification
The
patient has suffered a snake bite injury. The venom may have a neurotoxic, myotoxic,
cardiotoxic, procoagulant, anticoagulant, haemorrhagins, nephrotoxic, or necrotoxic effect. (1)
His
initial blood results indicate he likely has an acute rhabdomyolysis (elevated Creatine Kinase)
with secondary renal injury, likely from myoglobinuria. His urine output is 20mL/hr, which is sub-optimal
and in keeping with a picture of acute kidney injury. (1)
Notes
Fluid resuscitation and correction of electrolyte and acid-base disturbances should be initiated to
prevent acute kidney injury.
References
http://www.toxinology.com/
http://emedicine.medscape.com/article/1007814-treatment#a1156
Question 11 : FT
Question Information:
A 68-year-old man is admitted to the intensive care unit following an out of hospital cardiac arrest with a
prolonged down time (estimated to be 50 minutes). Overnight, his pupils became fixed and dilated.
Certification of brain death occurred at 0930 the following morning in the presence of senior consultant
doctors. The ventilator is turned off at 1630.
Question:
What is the time of death? (1 mark)
Choice 1: null Score : 0
Choice Feedback:
Answer
0930 (1)
Notes
Certification
of brain death is the time of death
Synopsis
Recommended learning outcomes from this set of Anaesthetics and ICU SAQs include:1.Diabetic
ketoacidosis2.Gentamicin dosing3.Gastric motility agents4.Electrolyte disturbances in total parenteral
nutrition5.Central venous catheter complications6.Fluid management in burns7.Disseminated
intravascular coagulopathy8.Sepsis9.Complications of transfusion10.Complications of snakebite
injury11.Certification of death