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What's the Investigation Station About ?

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What's the Investigation Station About ?

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Format:
4 Questions
Each Question has about 3-4 sub questions
Each question lasts 3-4 minutes
Usually starts with you being given an investigation & a scenario.

Types of investigations:
Anything you may encounter perioperatively, of relavance to anaesthesia / perioperative period / ICU.

Typically:

ECGs
X-rays - CXR, C-Spine, CT Head, etc
Blood Investigations
POCUS - Heart / Lungs
Pulmonary Function Tests
Arterial Blood Gases
etc

A DETAILED SYLLABUS FOR THE INVESTIGATION STATION IS PROVIDED ON THE DGMS WEBSITE. THE LINK IS BELOW:

INVESTIGATION STATION SYLLABUS

THE SYLLABUS FOR MMED PART B CAN BE FOUND HERE

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How to interpret FBC - Also available on TikTok

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How to interpret FBC - Also available on TikTok

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Here is a simple description of evaluation of FBC, from Geeky Medics. Of relevance - They can also be found on TikTok !

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Improve Article 👀

Introduction

This guide provides a structured approach to the interpretation of a full blood count (a.k.a. FBC, complete blood count, CBC) which you should be able to apply in most circumstances.

Note: This guide is only relevant to non-pregnant adults as normal ranges differ significantly in pregnant patients and in the paediatric population.

You might also be interested in our medical flashcard collection which contains over 1000 flashcards that cover key medical topics.

What tests are included in a FBC?

The full blood count gives insight into the cellular components of blood including white blood cells, red blood cells, and platelets providing numerical values relating to these cells (e.g. amount of them, size, contents). These results provide vital clues to the presence of underlying pathology. The long list of acronyms and numbers can seem daunting at first, however, by following a structured approach you can make sense of them all!

A standard FBC can be broken down into the following red cell, white cell and platelet tests.

Red cell tests

Red cell tests include:

Haemoglobin (Hb)

Haematocrit (Hct)

Mean corpuscular volume (MCV)

Red cell distribution width (RDW)

Red cell count (RCC)

Reticulocyte count

Mean corpuscular haemoglobin (MCH)

Mean corpuscular haemoglobin concentrate (MCHC)

White cell tests

White cell tests include:

Platelet tests

Platelet tests include:

Platelet count

Mean platelet volume (MPV)

Platelet distribution width (PDW)

Tip: Those tests shown in bold are the most important to understand and those that this article will focus on. However, some laboratories will provide results for all the above and more as part of a standard full blood count. These additional results tend to be used in more specific situations by specialists.

You might also be interested in our OSCE Flashcard Collection which contains over 2000 flashcards that cover clinical examination, procedures, communication skills and data interpretation.

Reference ranges

We have included key reference ranges below to assist you when interpreting a full blood count.

Haemoglobin (Hb):

White cell count (WCC):

Platelet count: 140 - 400 x10 ⁹/L

Red cell count (RCC):

Haematocrit:

Mean cell volume (MCV): 80 - 100 fL

Mean corpuscular haemoglobin (MCH): 27 - 32 pg/cell

Reticulocyte count: 0.2 - 2%

Note: Reference ranges are lab-specific, therefore always refer to your local reference ranges when interpreting a full blood count.

Red cell tests

Red cell tests can quantify the amount of haemoglobin/red cells present in a sample:

An abnormally low number of haemoglobin/red cells is known as anaemia

An abnormally high number of haemoglobin/red cells is known as polycythaemia.

Red cell tests can also provide important insights into the underlying cause(s) of anaemia or polycythaemia by looking at the average size of the cells and how much haemoglobin is contained within them.

Haemoglobin (Hb)

Anaemia

Anaemia refers to a decrease in the total amount of haemoglobin in the blood.

There are a wide range of causes of anaemia, which can be sub-categorised based on the average red cell size (mean cell volume/MCV):

Microcytic anaemia: low haemoglobin associated with a reduced MCV

Macrocytic anaemia: low haemoglobin associated with an increased MCV

Normocytic anaemia: low haemoglobin associated with a normal MCV

When you identify a low haemoglobin, you should look to the MCV to see which sub-type of anaemia is present as this information, alongside a good clinical assessment, can help narrow the differential diagnosis.

In general, when you identify anaemia it is sensible to check haematinics (e.g. ferritin, B12/folate) as deficiencies are common and easy to treat.

Polycythaemia

Polycythaemia is an abnormally high haemoglobin concentration, this is usually seen alongside an elevated haematocrit (the percentage of blood that is made up by red cells). Polycythemia can be due to an increase in the number of red cells, termed absolute polycythaemia, or it can be caused by a decrease in the amount of blood plasma (the liquid component of blood), which is termed relative polycythaemia. Absolute polycythemia can be caused by an issue in the bone marrow leading to a proliferation of red cell precursors (primary polycythaemia) or conditions that increase the amount of erythropoietin (EPO) circulating in the blood (secondary polycythaemia). EPO is a hormone produced in the kidneys which stimulates the bone marrow to make more red blood cells. As a result, when there is a state of EPO excess, this leads to polycythemia.

Primary polycythaemia is typically caused by myeloproliferative neoplasms (e.g. polycythaemia rubra vera).

Secondary polycythaemia has a wide range of possible causes, some of these create a chronic state of hypoxia while some are due to ectopic EPO production or stimulation. Some examples of causes of secondary polycythaemia include:

Relative polycythaemia involves a reduction in the volume of blood plasma causing red blood cells to become more concentrated while the actual number of them does not change (like putting less water into cordial would make a more concentrated drink, less plasma in the blood sample will concentrate the red blood cells). This can be caused by low fluid intake or states of excess fluid loss, such as significant burns.

Tip: Most polycythaemia is secondary, with the most common causes being smoking and excess alcohol intake.

Mean corpuscular volume (MCV)

Mean corpuscular volume (MCV) is a measure of the average size of the red cells present in the blood sample. This test is particularly useful in the context of anaemia, where it can be used to aid the differential diagnosis of potential underlying causes and guide which investigations to perform next.

The following list of underlying causes are 'textbook' but there is often some overlap between them. For instance, don't assume a patient with a macrocytosis cannot also be iron deficient.

Microcytic anaemia

Causes of microcytic anaemia include:

Iron deficiency anaemia: the commonest cause in the UK (see our article on iron deficiency anaemia)

Haemoglobinopathies (e.g. thalassemia syndrome/trait)

Anaemia of chronic disease/inflammation (can be microcytic, but often normocytic)

Lead poisoning (rare)

Sideroblastic anaemia (rare)

Hookworm infection (a common cause of microcytic anaemia in low/middle-income countries)

Hint: An acronym to remember the causes of microcytic anaemia is TAILS: Thalassemia/haemoglobinopathies, Anaemia of chronic disease/inflammation, Iron deficiency anaemia, Lead poisoning, S ideroblastic anaemia

Normocytic anaemia

Causes of normocytic anaemia include:

Anaemia of chronic disease/inflammation

Acute blood loss

Increase plasma volume (e.g. pregnancy, fluid overload)

Mixed aetiology anaemias

Haemoglobinopathies (e.g. thalassaemias)

Aplastic anaemia

Haemolysis

Hypersplenism (leads to increased destruction of red blood cells)

Macrocytic anaemia

Causes of macrocytic anaemia include:

B12/folate deficiency

Toxins (e.g. alcohol, chemotherapy)

Liver disease

Reticulocytosis (reticulocytes are immature red blood cells)

Pregnancy

Myeloma

Myelodysplastic syndrome

Hypothyroidism

Haematocrit (Hct)

Haematocrit (Hct) is the percentage of the blood sample that is made up of red cells and tends to closely follow the trend of the haemoglobin level and red cell count. Haematocrit can be affected by either the number of red blood cells or the volume of blood plasm a.

A raised haematocrit can result in increased blood viscosity due to there being a high number of red cells relative to blood plasma making blood 'sticky'. If the haematocrit continues to rise, hyperviscosity syndrome can develop, which is associated with the development of thrombi and symptoms such as headaches, blurred vision and chest pain. To prevent hyperviscosity some patients require venesection to reduce their haematocrit to safe levels with specific target levels varying depending on the underlying cause of the polycythemia.

Red cell count

Red cell count is the number of red cells present per unit volume of blood. This test can be used in combination with the haemoglobin level and the haematocrit to confirm the presence of anaemia or polycythaemia. The causes of a high or low red cell count are the same as those for haemoglobin and haematocrit.

Red cell distribution width (RDW)

Red cell distribution width (RDW) is useful to take a more in-depth look at the MCV (average of the red cell size). The RDW is a range from the largest red cell present to the smallest red cell present. This is useful information in the context of mixed anaemia (i.e. anaemia involving the presence of both macrocytic red cells and microcytic red cells). Mixed anaemia may develop in conditions where absorption from the gut is impaired, such as coeliac disease, leading to deficiencies in both iron (which typically causes microcytic anaemia) and B12/folate (which typically causes macrocytic anaemia). In these situations, the MCV can be misleadingly normal, however, this large variation in red cell size will be evident with an elevated RDW. The presence of red cells of varying sizes is known as anisocytosis and can be associated with iron deficiency anaemia as well.

Reticulocyte count

A reticulocyte is an immature red cell that is normally released from the bone marrow into the peripheral blood, fully maturing into a red blood cell within 24 hours. Therefore, the reticulocyte count can be used to assess the response of the bone marrow to anaemia.

A raised reticulocyte count in the context of anaemia implies that the bone marrow is effectively functioning to produce lots of new red blood cells to correct the anaemia. This would therefore suggest red blood cells are being destroyed in the peripheral circulation (e.g. haemolysis, bleeding) rather than there being an issue with the production of red blood cells in the bone marrow itself.

Whereas, a low reticulocyte count in the context of anaemia implies a problem with the bone marrow not being able to make enough cells. This could be due to nutritional deficiencies (e.g. B12/folate or iron) or a primary bone marrow disorder (e.g. aplastic anaemia, bone marrow infiltration from solid organ malignancies).

A raised reticulocyte count in the absence of anaemia may indicate that the body is effectively compensating for blood loss or haemolysis (i.e. the increased production is managing to replenish the number of cells being lost in the peripheral circulation). Alternatively, a raised reticulocyte count in the absence of anaemia may be due to the body adapting to increased oxygen demands.

White cell tests

Leukocytosis

A high white cell is known as leukocytosis and can be caused by a wide range of pathological processes. Important factors in determining the cause of leukocytosis include the rate of the white cell count rise and which type of white cell(s) are raised.

Common causes of acute leukocytosis:

Reactive: infection, inflammation, post-surgery

Steroids: stress response (i.e. endogenous steroids) or medication (i.e. exogenous steroids)

Haematological: acute leukaemias

Common causes of chronic leukocytosis:

Reactive: chronic infection, smoking

Haematological: leukaemia, certain subtypes of lymphoma

Hyposplenism: typically mild

Pregnancy

Neutrophils and lymphocytes make up the majority of the white cells in the blood, so these two cell types are usually the cause of a raised total white cell count.

A comprehensive assessment is always required to help narrow the differential diagnosis of leukocytosis and guide the need for further investigations.

Leukopenia

A low white cell count is known as leukopenia and can also be caused by a wide range of pathological processes.

Important factors in determining the cause of leukopenia include the rate of the white cell count fall and the type of white cell(s) which are low.

Neutrophils and lymphocytes account for the majority of white cells in the blood, so these types of white cells are typically reduced in the context of leukopenia.

A comprehensive assessment is always required to help narrow the differential diagnosis of leukopenia and guide the need for further investigations.

Common causes of leukopenia include:

Infection: can be seen as a transient phenomenon in viral illness or as a result of consumption in sepsis

Medications: antibiotics, immunosuppressants, anti-epileptics, cytotoxic agents (e.g. chemotherapy)

B12/folate deficiency

Autoimmune disease

Iron deficiency

HIV (any cytopenia could be due to HIV)

Racial variation: middle eastern and black patients can have lower baseline neutrophil counts which are not pathological

Bone marrow failure: often this will be seen alongside low platelets and low haemoglobin

White cell differential

Neutrophils

Neutrophils usually account for 40-70% of the total white blood cells and are key in the acute phase of infection (particularly bacterial infections).

As most of the white cells present in the blood are neutrophils, the causes of a high neutrophil count are the same as those that cause a high total white cell count.
Neutropenia
As most of the white cells present in the blood are neutrophils, the causes of a low neutrophil count are the same as those that cause a low total white cell count.

Hint: When neutrophil counts are low (<1.5) there is a higher infection risk. For this reason, if a neutropenic patient is febrile it is a medical emergency that requires prompt treatment with broad-spectrum intravenous antibiotics. This is known as neutropenic sepsis or febrile neutropenia.

Lymphocytes

Lymphocytes make up between 18-42% of white cells found in circulating blood. There are various subtypes with slightly different functions which play key roles in many aspects of the immune system, including fighting viral infections.
Lymphocytosis
A raised lymphocyte count is not uncommon and is typically due to a benign cause (e.g. viral infection). However, in some cases, a raised lymphocyte count may be caused by an underlying haematological malignancy.

Causes of lymphocytosis include:

Viral infection

Smoking

Hyposplenism/post-splenectomy

Malignancy: leukaemia and certain types of lymphoma

Pertussis: rates are increasing in the U.K. with decreased vaccination rates

Lymphopenia
Lymphopenia is usually due to a benign transient cause (e.g. infection) and rarely causes any long term issues. However, it can be also indicative of more serious underlying pathology.

Causes of lymphopenia include:

Infection

Older age (rarely clinically significant in this context)

Alcohol excess

HIV

Autoimmune disease

Bone marrow disease

Medications: cytotoxic agents, immunosuppressants

Renal failure

Congenital immunodeficiency disorders (e.g. Wiskott-Aldrich syndrome)

Monocytes

Monocytes make up about 4% of the total white cell count. They also play an important role in the immune system, becoming macrophages or dendritic cells in the periphery and taking part in phagocytosis, antigen presentation and cytokine production.
Monocytosis
A high monocyte count (monocytosis) is usually an acute finding in response to inflammation or infection.

Common causes of monocytosis include:

Bacterial infection

Autoimmune disease

Steroids

Monocytopenia
A low monocyte count (monocytopenia) is not usually clinically relevant unless it is very low (i.e. near 0).

Causes of a very low monocyte count include:

Acute infection

Steroids

Bone marrow failure

Cytotoxic agents (e.g. chemotherapy)

Hairy cell leukaemia

Eosinophils

Eosinophils account for between 2-3% of the total white cell count. They migrate to sites of inflammation and are key in the immune response to helminth infections. Once activated, eosinophils release reactive oxygen species and enzymes causing local tissue damage. Eosinophils are implicated alongside basophils and mast cells in the underlying pathophysiology of asthma. They also have various non-immunological functions which are beyond the scope of this article.

Due to eosinophils making up such a small percentage of white cells, a reduced number of eosinophils is not usually clinically relevant.
Eosinophilia
There is a wide range of possible causes of a raised eosinophil count (eosinophilia). As a result, a comprehensive clinical assessment is required to guide any potential further investigations.

Causes of eosinophilia include:

Allergies/atopy

Parasitic infection

Autoimmune disease (e.g. vasculitis)

Medications (e.g. antibiotics, anti-epileptics, allopurinol)

Gastrointestinal disease (e.g. eosinophilic oesophagitis)

Respiratory disease (e.g. asthma)

Malignancy (any solid organ or haematological)

Basophils

Basophils are the least common type of white blood cell making up just 0.5-1% of the total white cell count. They have granules containing histamine and serotonin which promote inflammation as part of the immune response, as well as heparin which prevents blood from clotting improving the blood supply to the inflamed tissue. Like eosinophils, basophils play key roles in parasitic infections and allergies. Basophils bind IgE to a receptor on their cell surface acting as part of the selective response to environmental substances. As basophils make up such a low percentage of total white cells in healthy individuals, there is usually little clinical significance in a low basophil count.

Transient, isolated basophilia is rarely clinically significant as it can be caused by many benign processes. However, when basophilia is present alongside elevated neutrophil and eosinophil counts or if the elevation is significantly above the normal range, this should raise the suspicion of a myeloproliferative disorder and prompt discussion with a haematologist.

Causes of basophilia include:

Allergic reactions/atopy

Iron deficiency

Chronic inflammation

Hypothyroidism

Infection

Haematological malignancies (myeloproliferative disorders)

Blasts

Blasts are immature cells that are usually only found in the bone marrow where they complete their maturation before being released into the circulation. The presence of high numbers of blasts in the circulating blood is abnormal and could be caused by leukaemia, hence this should prompt an urgent haematology assessment including a blood film and a bone marrow biopsy.

Causes of an elevated blast count include:

Acute leukaemia

Myeloproliferative disorders

Reactive (severe infection or treatment with G-CSF)

Cytotoxic agents (chemotherapy)

Platelet tests

Platelet count

Platelets (a.k.a. thrombocytes) are disc-shaped cell fragments that react to blood vessel injury by clumping to initiate the formation of a blood clot.

The platelet count is the number of platelets present per unit volume of blood. This can be high (thrombocytosis) or low ( thrombocytopenia).

Low platelet count

A reduced platelet count (thrombocytopenia) increases the risk of bleeding due to a reduced ability to form blood clots. Clinical features of thrombocytopenia include mucosal bleeding (e.g. epistaxis, bleeding gums) and spontaneous bruising.

The causes of a low platelet count can be grouped into acute and chronic.

Causes of acute thrombocytopenia:

Consumption (e.g. infection, bleeding)

Acute viral infection

Medications (e.g. antibiotics, anti-epileptics, cytotoxic agents)

Disseminated intravascular coagulation/microangiopathic haemolytic anaemia (e.g. TTP, HUS)

Heparin-induced thrombocytopenia (HIT)

Immune thrombocytopenic purpura (ITP)

Pregnancy: pre-eclampsia/HELLP syndrome

Causes of chronic thrombocytopenia:

Hypersplenism

Cirrhosis

Alcohol excess

Medications (e.g. anti-epileptics, cytotoxic agents)

ITP

Autoimmune disease

B12/folate deficiency

Iron deficiency

HIV

Hepatitis B/C

Haematological disease

Bone marrow failure

Thrombocytosis

A raised platelet count is known as thrombocytosis and has lots of potential causes.

Causes of thrombocytosis include:

Reactive: inflammation/infection

Myeloproliferative disorders: typically essential thrombocythaemia although any myeloproliferative disorder can elevate platelet counts

Iron deficiency

Hypospenlism/post-splenectomy

Underlying malignancy: likely secondary to underlying inflammatory processes

Hint: When an elevated platelet count is reactive, there is no increased clotting risk and the count tends to normalise after treatment of the underlying cause.

Reviewers

Dr Hannah Bielby
Haematology Registrar
Dr Callum Wright
Haematology Registrar
Further reading

For those wanting to improve their overall understanding of haematology, I've found the following books really useful:

Barbara J Bain. A beginner's guide to blood cells. Published 2017.

Barbara J Bain. Haematology: A Core Curriculum. Published 2010.

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Full Blood Count Interpretation | FBC | OSCE | Geeky Medics

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Improve Article 👀 This guide provides a structured approach to the interpretation of a full blood count (a.k.a. FBC, complete blood count, CBC) which you should be able to apply in most circumstances. Note: This guide is only relevant to non-pregnant adults as normal ranges differ significantly in pregnant patients and in the paediatric population.

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A 67 year old man complains of SOB and chest pain in the PACU. He has just undergone ORIF of elbow # with a supraclavicular block. SpO2 is 89% and BP is 85/45.

1) Describe the CXR findings

2) What is the diagnosis?

3) List the complications of supraclavicular block

4) What is your immediate management in PACU.

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A-Z of ECG Interpretation
It's useful to have a systematic and structured way to interpret ECGs.
Use any method you like. Develop your own. This one is from Oxford Medical Education.

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In case you have forgotten stuff from medical school.

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This ECG is from a MMED Anaesthesia OSCE Investigation Station.

The questions were something like this:

A 50 yr old male is post op day 1 ORIF #Tibia for a crush injury. The nurse was concerned about the ECG on the monitor and obtains a 12 lead ECG.

1) What abnormalities are present in this ECG?

2) What is your differential diagnosis?

You are now shown a set of blood results:

CK-MB Normal
CK > 20,000
K 7.5
Ur 16
Cr 185
Urine Dipstick - Blood ++ Myoglobin ++

3) What is your diagnosis ?

4) What is your immediate management ?

Read More Here:

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A 65 year old male is day 1 post op CABG. He is on the CTICU, but has recurrent episodes of ECG abnormalities. One such episode was captured here. The episodes are self limiting, last for about 15 - 30 seconds, but are increasing in frequency.

1) What does the ECG show?

2) List the possible causes for this in our patient?

3) What investigations would you request ?

4) The patient has another episode, during which he becomes unconscious with unrecordable BP. Describe your immediate management.

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1) List the TYPES of pacemaker failure.

2) What type of pacemaker failure is shown here ?

3) List the possible CAUSES for pacemaker failure.

4) Describe the pacemaker coding system.

5) Your patient with this ECG presents for emergency laparotomy. Describe your preoperative management.

A brief summary of pacemakers can be found here

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A 55 year old man presents for urgent laparotomy for perforated bowel. He gives a history of syncope 10 years ago, but was never followed up. This is his ECG.

1) Describe the pathological ECG findings.

2) What are the potential risks of surgery and anaesthesia ?

3) List the drugs that should be avoided ?

4) The patient develops Torsades post intubation. What is your management ?

Read more here:

Anaesthesia For Patients with Congenital Long QT

Long QT Syndrome and Perioperative Torsades de Pointes: What the Anesthesiologist Should Know

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On a late night pre op visit, you come across a 45 year old lady scheduled for Left Breast WLE first thing tomorrow am.

1) List the medical conditions that could be responsible for the above ECG.

2) What pertinent points in the history and physical examination may suggest a pathological cause ?

3) What further investigations would you request if any ?

4) How will you decide whether to proceed with the case ?

Feel free to edit this or any question.

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You are about to leave PACU after a long day when the nurse calls you to look at a patient. His rhythm strip is shown above.

You can either create a scenario and questions to share with your colleagues or just make a diagnosis.

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You see this ECG in a patient presenting at the AOCC clinic for preop evaluation. His exercise tolerance is limited due to OA and he is anxious to get his TKR done next week.

1) Describe the ECG findings

2) What could be the underlying causes for this ECG ?

3) What further information could help you decide management ?

4) The patient has no past medical history, and no other investigations in his record. How would you proceed preoperatively ?

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You can either create a scenario and questions,

or just make diagnosis. Doing the former may be more useful.

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A 66 year old lady has the following rhythm seen on her vitals monitor in PACU. She is post op laparoscopic cholecystectomy.

1 a) What is the diagnosis ?

1 b) Is this rhythm concerning ? Why ?

2) What are the possible causes for this rhythm ?

3) What further investigations would you request ?

4) What is your management ?

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A 50 year old lady presents for lap cholecystectomy. This is her preoperative ECG.

1) Describe the pertinent ECG findings.

2) What is your diagnosis ?

3) What other pre-excitation syndromes are you aware off ?

4) What are the potential complications of anaesthesia and surgery ?

Read More:

Perioperative Management of Pateints with pre-excitation syndromes.

SVTs and their management.

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Feel free to create a scenario. This has come up in the Investigation station before.

Reading -

1) Book Chapter by Peter Slinger

2) Review article in EJA

3) BJA Educational Article - Anaesthesia for Mediastinoscopy

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There are modules on Cardiac and Lung Ultrasound here.

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Online Learning Program Our Modules We currently have 4 modules to offer. Start with the Basic Ultrasound Physics Module. This will give you a good foundation to build on for the Focused Cardiac Ultrasound & Lung Ultrasound Modules. Gastric Ultrasound, Airway Ultrasound and eFAST modules coming soon.

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One way of structuring your answers for CXR interpretation.

Here is another way if you are more 'kiasu' - THE A to I method:

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Life in the Fast Lane * LITFL * Medical Blog

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Chest X-Rays (CXR) are routine investigation in clinical practice and consequently it is important for medical students and clinician's alike to know how to interpret them. There are many approaches to CXR interpretation, each trying to ensure that key abnormalities are identified and no area is overlooked.

Many people would be familiar with the ABC method to interpreting CXRs.

This is a simple way of approaching CXR, and it works for many people, however some people still struggle using this approach. DRSABCD is a familiar acronym for those who have undertaken First Aid/Basic Life Support courses. Now DRSABCDE can used as a simple, yet comprehensive, approach to CXR interpretation.

D - Details

Before you even begin interpreting a CXR you should have the correct details. This includes;

Patient name, age / DOB, sex

Type of film - PA or AP, erect or supine, correct L/R marker, inspiratory/expiratory series

Date and time of study

R - RIPE (assessing the image quality)

Next up, how " ripe " is the image. That is, what is the technical quality of the film?

Rotation - medial clavicle ends equidistant from spinous process

Inspiration - 5-6 anterior ribs in MCL or 8-10 posterior ribs above diaphragm, poor inspiration?, hyperexpanded?

Picture - straight vs oblique, entire lung fields, scapulae outside lung fields, angulation (ie 'tilt' in vertical plane)

Exposure (Penetration) - IV disc spaces, spinous processes to ~T4, L) hemidiaphragm visible through cardiac shadow.

S - Soft tissues and bones

SOFT TISSUES/BONES

In CXR interpretation it is common to leave soft tissues until the end.

Ribs, sternum, spine, clavicles - symmetry, fractures, dislocations, lytic lesions, density

Soft tissues - looking for symmetry, swelling, loss of tissue planes, subcutaneous air, masses

Breast shadows

Calcification - great vessels, carotids

A - Airway & mediastinum

AIRWAY

Trachea - central or slightly to right lung as crosses aortic arch

Paratracheal/mediastinal masses or adenopathy

Carina & RMB/LMB

Mediastinal width <8cm on PA film

Aortic knob

Hilum - T6-7 IV disc level, left hilum is usually higher (2cm) and squarer than the V-shaped right hilum.

Check vessels, calcification.

B - Breathing

Vascularity - to ~2cm of pleural surface (~3cm in apices), vessels in bases > apices

Pneumothorax - don't forget apices

Lung field outlines - abnormal opacity/lucency, atelectasis, collapse, consolidation, bullae

Horizontal fissure on Right Lung

Pulmonary infiltrates - interstitial vs alveolar pattern

Coin lesions

Cavitary lesions

Pleural reflections

Pleural thickening

C - Circulation

CIRCULATION

Heart position -⅔ to left, ⅓ to right

Heart size - measure cardiothoracic ratio on PA film (normal <0.5)

Heart borders - R) border is R) atrium, L) border is L) ventricle & atrium

Heart shape

Aortic stripe

D - Diaphragm

Hemidiaphragm levels - Right Lung higher than Left Lung (~2.5cm / 1 intercostal space)

Diaphragm shape/contour

Cardiophrenic and costophrenic angles - clear and sharp

Gastric bubble / colonic air

Subdiaphragmatic air (pneumoperitoneum)

E - Extras
Further Reading

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DRSABCDE of CXR Interpretation * LITFL * Examination Medicine

# data[].attributes.attachment_link.description
Chest X-Rays (CXR) are routine investigation in clinical practice and consequently it is important for medical students and clinician's alike to know how to interpret them. There are many approaches to CXR interpretation, each trying to ensure that key abnormalities are identified and no area is overlooked.

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Write a scenario and some questions.

Read more:

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Marcin Migaczewski et al. VideoSurgery & Miniinvasive Surgery. Creative Commons. Figure - available via license: Creative Commons Attribution-NonCommercial

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Create ....

Read More:

All you need to know about anaesthesia for esophageal surgery

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A patient with the above x ray is scheduled for TURBT.

1) List the implications of his medical condition for anaesthesia.

2) What further investigations would you request pre operatively ? Give reasons for each investigation.

3) List possible cervical spine pathology in this patient that may impact anaesthesia management.

Reading:

If you don't have time, just read this - The AAABBBCs method to read a C-Spine xray

1) Rheumatoid arthritis and anaesthesia

2) Anaesthesia for the adult patient with rheumatoid arthritis

3) Cervical Spine complications of rheumatoid

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This has come out in MMED OSCE before !

How to interpret a CT Head - Blood Can Be Very Bad (BCBVB) - by Dr Andrew Perron

Tell us how you do it - what's your method ?

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Easiest on laptop/desktop.
Mobile works.
Open up the post - top right hand corner 3 dots.
Scroll through posts like a presentation.
Watch the screencast video for details

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A 45 year old man is rushed to the OT from the emergency room for decompressive craniectomy. This is his CT Head.

1) Describe the likely clinical symptoms and signs that he may have presented with.

2) Describe the CT head. What is the diagnosis ?

3) What can you do as an anaesthetist to control intracranial pressure?

4) The patient is transferred to ICU post op. What methods of CBF and ICP monitoring are you aware of?

Read More:

Cerebral Physiology - BJA

Monitoring the Injured Brain - ICP and CBF - BJA - It's a bit old from 2006, check elsewhere for updates

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ABGs by Dr Hatton - anaesthesiologist from Kentucky

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ABGs by Dr Hatton - anaesthesiologist from Kentucky

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Watch Part 2 of his explanation below

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University of Kentucky Department of Anesthesiology

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By Dr Hatton...

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University of Kentucky Department of Anesthesiology

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From the American College of Physicians - probably covers all you need to know !

Article here.

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A 30 year old man sustains blunt traumatic injury to his chest. As part of the eFAST scan the above is seen in the cardiac box.

1) Which view is shown ? What are the other required views for a complete eFAST scan ?

2) Describe the findings. What is the diagnosis ?

3) What ECG findings are associated with this ?

4) He is tachycardic with a BP of 60/35. The CTVS team wants to bring him to EOT for emergency sternotomy. Describe your management.

Read/Watch More:

Perioperative Implications of Pericardial Effusions - BJA Ed

Echocardiographic Assessment of Pericardial Effusion by Peters & Schuck

A great tutorial on eFAST by Vi Dinh - POCUS 101

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Feel free to edit and create a scenario.

Read More:

More about imaging in PE

European Soc cardiology: PE: Role of Echo

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I'll huff and I'll puff and I'll blow your house down

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I'll huff and I'll puff and I'll blow your house down

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Feel free to create

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CT Neck From Tunio et al. License under Creative Commons 2.0

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A 72 year old lady presents for total thyroidectomy and neck dissection. This is her CT neck.

1) Write some questions....

Read More:

Anaesthesia for Head & Neck Cancer Surgery

Imaging in Head and Neck Cancers - BJA Ed

eFONA - BJA Ed

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A 22 year old man is brought in unconscious to the EMD. His friend gives a history of him consuming some unknown liquid.

1) Describe the ABG and comment on the type of acid base abnormality.

2) Explain your reason for your chosen type of acid base abnormality.

3) What is the calculated osmolarity ? How did you calculate this ?

4) What is the osmolar gap ? How did you determine this ?

5) What is the most likely diagnosis ?

Read more:

Mind the Gap from ATS Journal

LITFL - Osmolar Gap

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How to communicate and describe transducer manipulations. A standardised method.

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Radiological Features

Recent Developments & Anaesthetic Implications

Video - C-Spine Interpretation - AABBCDEs

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"Iron makes you strong like a lion" Harry Belafonte

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"Iron makes you strong like a lion" Harry Belafonte

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This is the full blood count of a patient scheduled for elective FESS next week.

1) What is the most likely diagnosis and why ?

2) List the causes of this type of anaemia.

3) How would you optimize this patient preoperatively?

4) What would your expert opinion be on timing of surgery?

Read More From Association of Anaesthetists & BJA:

International consensus statement on the peri-operative management of anaemia and iron deficiency

Iron homeostasis and perioperative management of iron deficiency

Ask Dr Chris King