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

The ATLS guidelines categorize chest injuries in trauma into two groups: life-threatening injuries that require immediate identification and treatment in the primary survey, and potentially life-threatening injuries that should be identified and treated in the secondary survey.

During the primary survey, the focus is on identifying and treating life-threatening thoracic injuries. These include airway obstruction, tracheobronchial tree injury, tension pneumothorax, open pneumothorax, massive haemothorax, and cardiac tamponade. Prompt recognition and intervention are crucial in order to prevent further deterioration and potential fatality.

In the secondary survey, attention is given to potentially life-threatening injuries that may not be immediately apparent. These include simple pneumothorax, haemothorax, flail chest, pulmonary contusion, blunt cardiac injury, traumatic aortic disruption, traumatic diaphragmatic injury, and blunt oesophageal rupture. These injuries may not pose an immediate threat to life, but they still require identification and appropriate management to prevent complications and ensure optimal patient outcomes.

By dividing chest injuries into these two categories and addressing them in a systematic manner, healthcare providers can effectively prioritize and manage trauma patients, ultimately improving their chances of survival and recovery.

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.

An X-ray of the foot is recommended when there is pain in the base of the fifth metatarsal or the navicular bone, as well as an inability to bear weight immediately after an injury or in the emergency department. The Ottawa ankle rules can also be used to determine if an X-ray is necessary for ankle injuries. These rules focus on two specific areas (the malleolar and midfoot zones) to determine if an X-ray of the ankle or foot is needed. More information on these rules can be found in the notes below.

Further Reading:

Ankle fractures are traumatic lower limb and joint injuries that involve the articulation between the tibia, fibula, and talus bones. The ankle joint allows for plantar and dorsiflexion of the foot. The key bony prominences of the ankle are called malleoli, with the medial and posterior malleolus being prominences of the distal tibia and the lateral malleolus being a prominence of the distal fibula. The distal fibula and tibia are joined together by the distal tibiofibular joint or syndesmosis, which is comprised of three key ligaments. An ankle X-ray series is often used to guide clinical decision making in patients with ankle injuries, using the Ottawa ankle rules to determine if an X-ray is necessary. Ankle fractures are commonly described by the anatomical fracture pattern seen on X-ray relative to the malleoli involved, such as isolated malleolus fractures, bimalleolar fractures, and trimalleolar fractures. The Weber classification is a commonly used system for distal fibula fractures, categorizing them as Weber A, B, or C based on the level and extent of the fracture.

The ATLS guidelines categorize chest injuries in trauma into two groups: life-threatening injuries that require immediate identification and treatment in the primary survey, and potentially life-threatening injuries that should be identified and treated in the secondary survey.

During the primary survey, the focus is on identifying and treating life-threatening thoracic injuries. These include airway obstruction, tracheobronchial tree injury, tension pneumothorax, open pneumothorax, massive haemothorax, and cardiac tamponade. Prompt recognition and intervention are crucial in order to prevent further deterioration and potential fatality.

In the secondary survey, attention is given to potentially life-threatening injuries that may not be immediately apparent. These include simple pneumothorax, haemothorax, flail chest, pulmonary contusion, blunt cardiac injury, traumatic aortic disruption, traumatic diaphragmatic injury, and blunt oesophageal rupture. These injuries may not pose an immediate threat to life, but they still require identification and appropriate management to prevent complications and ensure optimal patient outcomes.

By dividing chest injuries into these two categories and addressing them in a systematic manner, healthcare providers can effectively prioritize and manage trauma patients, ultimately improving their chances of survival and recovery.

Blunt abdominal trauma often results in injury to the liver and spleen, which are the two organs most commonly affected. The liver, being the largest and located in a vulnerable position, is particularly prone to injury in such cases.

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.

Patients who have suffered burns should receive high-flow oxygen (15 L) through a reservoir bag while their breathing is being evaluated. If intubation is necessary, it is crucial to use an appropriately sized endotracheal tube (ETT). Using a tube that is too small can make it difficult or even impossible to ventilate the patient, clear secretions, or perform bronchoscopy.

According to the ATLS guidelines, adults should be intubated using an ETT with an internal diameter (ID) of at least 7.5 mm or larger. Children, on the other hand, should have an ETT with an ID of at least 4.5 mm. Once a patient has been intubated, it is important to continue administering 100% oxygen until their carboxyhemoglobin levels drop to less than 5%.

To protect the lungs, it is recommended to use lung protective ventilation techniques. This involves using low tidal volumes (4-8 mL/kg) and ensuring that peak inspiratory pressures do not exceed 30 cmH2O.

The airway is deemed at risk when the Glasgow Coma Scale (GCS) falls below 8. There are various factors that can lead to airway obstruction, including the presence of blood or vomit in the airway, a foreign object such as a tooth or food blocking the passage, direct injury to the face or throat, inflammation of the epiglottis (epiglottitis), involuntary closure of the larynx (laryngospasm), constriction of the bronchial tubes (bronchospasm), swelling in the pharynx due to infection or fluid accumulation (oedema), excessive bronchial secretions, and blockage of a tracheostomy tube.

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

The scalp is primarily supplied with blood from branches of the external carotid artery. The posterior half of the scalp is specifically supplied by three branches of the external carotid artery. These branches are the superficial temporal artery, which supplies blood to the frontal and temporal regions of the scalp, the posterior auricular artery, which supplies blood to the area above and behind the external ear, and the occipital artery, which supplies blood to the back of the scalp.

Further Reading:

The scalp is the area of the head that is bordered by the face in the front and the neck on the sides and back. It consists of several layers, including the skin, connective tissue, aponeurosis, loose connective tissue, and periosteum of the skull. These layers provide protection and support to the underlying structures of the head.

The blood supply to the scalp primarily comes from branches of the external carotid artery and the ophthalmic artery, which is a branch of the internal carotid artery. These arteries provide oxygen and nutrients to the scalp tissues.

The scalp also has a complex venous drainage system, which is divided into superficial and deep networks. The superficial veins correspond to the arterial branches and are responsible for draining blood from the scalp. The deep venous network is drained by the pterygoid venous plexus.

In terms of innervation, the scalp receives sensory input from branches of the trigeminal nerve and the cervical nerves. These nerves transmit sensory information from the scalp to the brain, allowing us to perceive touch, pain, and temperature in this area.