Shock is a condition characterized by inadequate tissue perfusion due to circulatory insufficiency. It can be caused by fluid loss or redistribution, as well as impaired cardiac output. The main causes of shock include haemorrhage, diarrhoea and vomiting, burns, diuresis, sepsis, neurogenic shock, anaphylaxis, massive pulmonary embolism, tension pneumothorax, cardiac tamponade, myocardial infarction, and myocarditis.

One common cause of shock is haemorrhage, which is frequently encountered in the emergency department. Haemorrhagic shock can be classified into different types based on the amount of blood loss. Type 1 haemorrhagic shock involves a blood loss of 15% or less, with less than 750 ml of blood loss. Patients with type 1 shock may have normal blood pressure and heart rate, with a respiratory rate of 12 to 20 breaths per minute.

Type 2 haemorrhagic shock involves a blood loss of 15 to 30%, with 750 to 1500 ml of blood loss. Patients with type 2 shock may have a pulse rate of 100 to 120 beats per minute and a respiratory rate of 20 to 30 breaths per minute. Blood pressure is typically normal in type 2 shock.

Type 3 haemorrhagic shock involves a blood loss of 30 to 40%, with 1.5 to 2 litres of blood loss. Patients with type 3 shock may have a pulse rate of 120 to 140 beats per minute and a respiratory rate of more than 30 breaths per minute. Urine output is decreased to 5-15 mls per hour.

Type 4 haemorrhagic shock involves a blood loss of more than 40%, with more than 2 litres of blood loss. Patients with type 4 shock may have a pulse rate of more than 140 beats per minute and a respiratory rate of more than 35 breaths per minute. They may also be drowsy, confused, and possibly experience loss of consciousness. Urine output may be minimal or absent.

In summary, shock is a condition characterized by inadequate tissue perfusion. Haemorrhage is a common cause of shock, and it can be classified into different types based on the amount of blood loss. Prompt recognition and management of shock are crucial in order to prevent further complications and improve patient outcomes

Low-velocity gunshot wounds to the abdomen result in tissue damage through laceration and cutting. On the other hand, high-velocity gunshot wounds transfer a greater amount of kinetic energy to the abdominal viscera. These types of wounds can cause more extensive damage in the surrounding area of the missile’s path due to temporary cavitation.

When patients experience penetrating abdominal trauma as a result of gunshot wounds, certain organs are more commonly injured. The small bowel is affected in approximately 50% of cases, followed by the colon in 40% of cases. The liver is injured in around 30% of cases, while abdominal vascular structures are affected in about 25% of cases.

Please note that these statistics have been obtained from the most recent edition of the ATLS manual.

FAST scans consist of four standard views that are obtained to assess different areas of the body. These views include the right upper quadrant (RUQ), left upper quadrant (LUQ), pericardial sac, and the pelvis.

In the RUQ view, the focus is on the right flank or peri-hepatic area, which includes Morison’s pouch and the right costophrenic pleural recess.

The LUQ view examines the left flank or peri-splenic area, which includes the spleen-renal recess and the left costophrenic pleural space.

The pericardial sac is also assessed to evaluate any abnormalities in this area.

Lastly, the pelvis is examined in two planes to ensure a comprehensive evaluation.

In addition to these four standard views, an anterior pleural view is often performed alongside the others. This view used to be part of the extended FAST (eFAST) scan but is now commonly included routinely.

Further Reading:

Abdominal trauma can be classified into two categories: blunt trauma and penetrating trauma. Blunt trauma occurs when compressive or deceleration forces are applied to the abdomen, often resulting from road traffic accidents or direct blows during sports. The spleen and liver are the organs most commonly injured in blunt abdominal trauma. On the other hand, penetrating trauma involves injuries that pierce the skin and enter the abdominal cavity, such as stabbings, gunshot wounds, or industrial accidents. The bowel and liver are the organs most commonly affected in penetrating injuries.

When it comes to imaging in blunt abdominal trauma, there are three main modalities that are commonly used: focused assessment with sonography in trauma (FAST), diagnostic peritoneal lavage (DPL), and computed tomography (CT). FAST is a non-invasive and quick method used to detect free intraperitoneal fluid, aiding in the decision on whether a laparotomy is needed. DPL is also used to detect intraperitoneal blood and can be used in both unstable blunt abdominal trauma and penetrating abdominal trauma. However, it is more invasive and time-consuming compared to FAST and has largely been replaced by it. CT, on the other hand, is the gold standard for diagnosing intra-abdominal pathology and is used in stable abdominal trauma patients. It offers high sensitivity and specificity but requires a stable and cooperative patient. It also involves radiation and may have delays in availability.

In the case of penetrating trauma, it is important to assess these injuries with the help of a surgical team. Penetrating objects should not be removed in the emergency department as they may be tamponading underlying vessels. Ideally, these injuries should be explored in the operating theater.

In summary, abdominal trauma can be classified into blunt trauma and penetrating trauma. Blunt trauma is caused by compressive or deceleration forces and commonly affects the spleen and liver. Penetrating trauma involves injuries that pierce the skin and commonly affect the bowel and liver. Imaging modalities such as FAST, DPL, and CT are used to assess and diagnose abdominal trauma, with CT being the gold standard. Penetrating injuries should be assessed by a surgical team and should ideally be explored in the operating theater.

A surgical cricothyroidotomy is a procedure performed in emergency situations to secure the airway by making an incision in the cricothyroid membrane. It is also known as an emergency surgical airway (ESA) and is typically done when intubation and oxygenation are not possible.

There are certain conditions in which a surgical cricothyroidotomy should not be performed. These include patients who are under 12 years old, those with laryngeal fractures or pre-existing or acute laryngeal pathology, individuals with tracheal transection and retraction of the trachea into the mediastinum, and cases where the anatomical landmarks are obscured due to trauma.

The procedure is carried out in the following steps:
1. Gathering and preparing the necessary equipment.
2. Positioning the patient on their back with the neck in a neutral position.
3. Sterilizing the patient’s neck using antiseptic swabs.
4. Administering local anesthesia, if time permits.
5. Locating the cricothyroid membrane, which is situated between the thyroid and cricoid cartilage.
6. Stabilizing the trachea with the left hand until it can be intubated.
7. Making a transverse incision through the cricothyroid membrane.
8. Inserting the scalpel handle into the incision and rotating it 90°. Alternatively, a haemostat can be used to open the airway.
9. Placing a properly-sized, cuffed endotracheal tube (usually a size 5 or 6) into the incision, directing it into the trachea.
10. Inflating the cuff and providing ventilation.
11. Monitoring for chest rise and auscultating the chest to ensure adequate ventilation.
12. Securing the airway to prevent displacement.

Potential complications of a surgical cricothyroidotomy include aspiration of blood, creation of a false passage into the tissues, subglottic stenosis or edema, laryngeal stenosis, hemorrhage or hematoma formation, laceration of the esophagus or trachea, mediastinal emphysema, and vocal cord paralysis or hoarseness.

Traumatic aortic rupture, also known as traumatic aortic disruption or transection, occurs when the aorta is torn or ruptured due to physical trauma. This condition often leads to sudden death because of severe bleeding. Motor vehicle accidents and falls from great heights are the most common causes of this injury.

The patients with the highest chances of survival are those who have an incomplete tear near the ligamentum arteriosum of the proximal descending aorta, close to where the left subclavian artery branches off. The presence of an intact adventitial layer or contained mediastinal hematoma helps maintain continuity and prevents immediate bleeding and death. If promptly identified and treated, survivors of these injuries can recover. In cases where traumatic aortic rupture leads to sudden death, approximately 50% of patients have damage at the aortic isthmus, while around 15% have damage in either the ascending aorta or the aortic arch.

Initial chest X-rays may show signs consistent with a traumatic aortic injury. However, false-positive and false-negative results can occur, and sometimes there may be no abnormalities visible on the X-ray. Some of the possible X-ray findings include a widened mediastinum, hazy left lung field, obliteration of the aortic knob, fractures of the 1st and 2nd ribs, deviation of the trachea to the right, presence of a pleural cap, elevation and rightward shift of the right mainstem bronchus, depression of the left mainstem bronchus, obliteration of the space between the pulmonary artery and aorta, and deviation of the esophagus or NG tube to the right.

A helical contrast-enhanced CT scan of the chest is the preferred initial investigation for suspected blunt aortic injury. It has proven to be highly accurate, with close to 100% sensitivity and specificity. CT scanning should be performed liberally, as chest X-ray findings can be unreliable. However, hemodynamically unstable patients should not be placed in a CT scanner. If the CT results are inconclusive, aortography or trans-oesophageal echo can be performed for further evaluation.

Immediate surgical intervention is necessary for these injuries. Endovascular repair is the most common method used and has excellent short-term outcomes. Open repair may also be performed depending on the circumstances. It is important to control heart rate and blood pressure during stabilization to reduce the risk of rupture. Pain should be managed with appropriate analgesic

ATLS guidelines now suggest administering only 1 liter of crystalloid fluid during the initial assessment. If patients do not respond to the crystalloid, it is recommended to quickly transition to blood products. Studies have shown that infusing more than 1.5 liters of crystalloid fluid is associated with higher mortality rates in trauma cases. Therefore, it is advised to prioritize the early use of blood products and avoid large volumes of crystalloid fluid in trauma patients. In cases where it is necessary, massive transfusion should be considered, defined as the transfusion of more than 10 units of blood in 24 hours or more than 4 units of blood in one hour. For patients with evidence of Class III and IV hemorrhage, early resuscitation with blood and blood products in low ratios is recommended.

Based on the findings of significant trials, such as the CRASH-2 study, the use of tranexamic acid is now recommended within 3 hours. This involves administering a loading dose of 1 gram intravenously over 10 minutes, followed by an infusion of 1 gram over eight hours. In some regions, tranexamic acid is also being utilized in the prehospital setting.

The Insall-Salvati ratio is determined by dividing the length of the patellar tendon (TL) by the length of the patella (PL). This ratio is used to compare the relative lengths of these two structures. A normal ratio is typically 1:1.

Further Reading:

A quadriceps tendon tear or rupture is a traumatic lower limb and joint injury that occurs when there is heavy loading on the leg, causing forced contraction of the quadriceps while the foot is planted and the knee is partially bent. These tears most commonly happen at the osteotendinous junction between the tendon and the superior pole of the patella. Quadriceps tendon ruptures are more common than patellar tendon ruptures.

When a quadriceps tendon tear occurs, the patient usually experiences a tearing sensation and immediate pain. They will then typically complain of pain around the knee and over the tendon. Clinically, there will often be a knee effusion and weakness or inability to actively extend the knee.

In cases of complete quadriceps tears, the patella will be displaced distally, resulting in a low lying patella or patella infera, also known as patella baja. Radiological measurements, such as the Insall-Salvati ratio, can be used to measure patella height. The Insall-Salvati ratio is calculated by dividing the patellar tendon length by the patellar length. A normal ratio is between 0.8 to 1.2, while a low lying patella (patella baja) is less than 0.8 and a high lying patella (patella alta) is greater than 1.2.

Recognizing the extent of blood loss based on vital sign and mental status abnormalities is a crucial skill. The Advanced Trauma Life Support (ATLS) classification for hemorrhagic shock correlates the amount of blood loss with expected physiological responses in a healthy individual weighing 70 kg. In terms of body weight, the total circulating blood volume accounts for approximately 7%, which is roughly equivalent to five liters in an average 70 kg male patient.

The ATLS classification for hemorrhagic shock is as follows:

CLASS I:
– Blood loss: Up to 750 mL
– Blood loss (% blood volume): Up to 15%
– Pulse rate: Less than 100 beats per minute (bpm)
– Systolic blood pressure: Normal
– Pulse pressure: Normal (or increased)
– Respiratory rate: 14-20 breaths per minute
– Urine output: Greater than 30 mL/hr
– CNS/mental status: Slightly anxious

CLASS II:
– Blood loss: 750-1500 mL
– Blood loss (% blood volume): 15-30%
– Pulse rate: 100-120 bpm
– Systolic blood pressure: Normal
– Pulse pressure: Decreased
– Respiratory rate: 20-30 breaths per minute
– Urine output: 20-30 mL/hr
– CNS/mental status: Mildly anxious

CLASS III:
– Blood loss: 1500-2000 mL
– Blood loss (% blood volume): 30-40%
– Pulse rate: 120-140 bpm
– Systolic blood pressure: Decreased
– Pulse pressure: Decreased
– Respiratory rate: 30-40 breaths per minute
– Urine output: 5-15 mL/hr
– CNS/mental status: Anxious, confused

CLASS IV:
– Blood loss: More than 2000 mL
– Blood loss (% blood volume): More than 40%
– Pulse rate: More than 140 bpm
– Systolic blood pressure: Decreased
– Pulse pressure: Decreased
– Respiratory rate: More than 40 breaths per minute
– Urine output: Negligible
– CNS/mental status: Confused, lethargic

If an adult with a head injury experiences more than one episode of vomiting, it is recommended to undergo a CT scan of the head. There are several criteria for an urgent CT scan in individuals with a head injury, including a Glasgow Coma Scale (GCS) score of less than 13 on initial assessment in the emergency department (ED), a GCS score of less than 15 at 2 hours after the injury on assessment in the ED, suspected open or depressed skull fracture, any sign of basal skull fracture (such as haemotympanum, ‘panda’ eyes, cerebrospinal fluid leakage from the ear or nose, or Battle’s sign), post-traumatic seizure, new focal neurological deficit, and being on anticoagulation medication. If any of these signs are present, a CT scan should be performed within 1 hour, except for patients on anticoagulation medication who should undergo a CT scan within 8 hours if none of the other signs are present. However, if a patient on anticoagulation medication has any of the other signs, the CT scan should be performed within 1 hour.

Further Reading:

Indications for CT Scanning in Head Injuries (Adults):
– CT head scan should be performed within 1 hour if any of the following features are present:
– GCS < 13 on initial assessment in the ED
– GCS < 15 at 2 hours after the injury on assessment in the ED
– Suspected open or depressed skull fracture
– Any sign of basal skull fracture (haemotympanum, ‘panda’ eyes, cerebrospinal fluid leakage from the ear or nose, Battle’s sign)
– Post-traumatic seizure
– New focal neurological deficit
– > 1 episode of vomiting

Indications for CT Scanning in Head Injuries (Children):
– CT head scan should be performed within 1 hour if any of the features in List 1 are present:
– Suspicion of non-accidental injury
– Post-traumatic seizure but no history of epilepsy
– GCS < 14 on initial assessment in the ED for children more than 1 year of age
– Paediatric GCS < 15 on initial assessment in the ED for children under 1 year of age
– At 2 hours after the injury, GCS < 15
– Suspected open or depressed skull fracture or tense fontanelle
– Any sign of basal skull fracture (haemotympanum, ‘panda’ eyes, cerebrospinal fluid leakage from the ear or nose, Battle’s sign)
– New focal neurological deficit
– For children under 1 year, presence of bruise, swelling or laceration of more than 5 cm on the head

– CT head scan should be performed within 1 hour if none of the above features are present but two or more of the features in List 2 are present:
– Loss of consciousness lasting more than 5 minutes (witnessed)
– Abnormal drowsiness
– Three or more discrete episodes of vomiting
– Dangerous mechanism of injury (high-speed road traffic accident, fall from a height.

The ability to rotate the neck actively by 45 degrees to the left and right is a crucial distinction between the ‘no risk’ and ‘low risk’ categories when applying the Canadian C-spine rules. In this case, the patient does not exhibit any high-risk factors for cervical spine injury according to the Canadian C-spine rule. However, they do have a low-risk factor due to their involvement in a minor rear-end motor collision. If a patient with a low-risk factor is unable to actively rotate their neck by 45 degrees in either direction, they should undergo imaging. It is important to note that while the patient’s use of anticoagulation medication may affect the need for brain imaging, it typically does not impact the decision to perform a CT scan of the cervical spine.

Further Reading:

When assessing for cervical spine injury, it is recommended to use the Canadian C-spine rules. These rules help determine the risk level for a potential injury. High-risk factors include being over the age of 65, experiencing a dangerous mechanism of injury (such as a fall from a height or a high-speed motor vehicle collision), or having paraesthesia in the upper or lower limbs. Low-risk factors include being involved in a minor rear-end motor vehicle collision, being comfortable in a sitting position, being ambulatory since the injury, having no midline cervical spine tenderness, or experiencing a delayed onset of neck pain. If a person is unable to actively rotate their neck 45 degrees to the left and right, their risk level is considered low. If they have one of the low-risk factors and can actively rotate their neck, their risk level remains low.

If a high-risk factor is identified or if a low-risk factor is identified and the person is unable to actively rotate their neck, full in-line spinal immobilization should be maintained and imaging should be requested. Additionally, if a patient has risk factors for thoracic or lumbar spine injury, imaging should be requested. However, if a patient has low-risk factors for cervical spine injury, is pain-free, and can actively rotate their neck, full in-line spinal immobilization and imaging are not necessary.

NICE recommends CT as the primary imaging modality for cervical spine injury in adults aged 16 and older, while MRI is recommended as the primary imaging modality for children under 16.

Different mechanisms of spinal trauma can cause injury to the spine in predictable ways. The majority of cervical spine injuries are caused by flexion combined with rotation. Hyperflexion can result in compression of the anterior aspects of the vertebral bodies, stretching and tearing of the posterior ligament complex, chance fractures (also known as seatbelt fractures), flexion teardrop fractures, and odontoid peg fractures. Flexion and rotation can lead to disruption of the posterior ligament complex and posterior column, fractures of facet joints, lamina, transverse processes, and vertebral bodies, and avulsion of spinous processes. Hyperextension can cause injury to the anterior column, anterior fractures of the vertebral body, and potential retropulsion of bony fragments or discs into the spinal canal. Rotation can result in injury to the posterior ligament complex and facet joint dislocation.