Anaesthetic considerations in polytrauma patients

Abstract

Trauma remains a major public health concern due to the high cost, associated morbidity, and mortality both in developed and developing countries. Management of polytrauma patients has advanced and improved over the last few decades with a better understanding of the pathophysiology of shock, resuscitation, and hemodynamic changes. Anaesthesia and application of anaesthetic principles have consequently evolved and can be applied in polytrauma patients throughout their journey of treatment beginning from pre-hospital care, emergency department resuscitation, surgical procedures, and rehabilitation. Providing immediate pain relief is an important component in the management of these patients. Performing peripheral nerve blocks in the pre-hospital setting when feasible or on arrival in the emergency room provides rapid pain relief, better patient co-operation, decreases the risk of chronic pain syndromes. This narrative evaluates the role of anaesthesia and anaesthesiologists in the management of polytrauma patients. The authors performed a thorough review of the literature using various databased of Medline, PubMed, Embase, and Google Scholar. The relevant papers were also searched manually from the cross-referencing of retrieved papers. Full papers published in English till September 25, 2020 were included for this review. The keywords included ‘trauma’, ‘difficult airway’, ‘anaesthesia’, ‘fluid and blood’, ‘monitoring’, ‘critical care’, ‘resuscitation’ and ‘surgery’ in various combinations. The holistic management of trauma victims requires a multidisciplinary time-based approach for an optimal outcome. The management starts from assessment and simultaneous management for the optimization of the trauma victim from the first point of contact itself. The anaesthetic technique of choice in the perioperative management of trauma patients depends on different factors such as neurological status, cardiovascular stability, type and duration of surgery, coagulation status. Regional techniques are to be used whenever possible due to the beneficial effects observed with these techniques. Various important aspects are being discussed in subsequent sections.

1. Introduction

Trauma remains the third commonest cause of mortality across all age groups and the most common cause of mortality in individuals up to the age of 45 years.¹ An improved understanding of the pathophysiology of polytrauma has evolved over the past three decades including evolving models of trauma care which has helped guide the anaesthetic care of patients requiring surgical intervention.^2,3 The role of anaesthesia in polytrauma requires an integrated, team approach. The optimal management of patients of trauma requires a multi-disciplinary, multimodal, and coordinated team approach for a successful outcome.⁴ Trauma anaesthesia begins before the patient arrives with a role in pre-hospital set-up followed by sedation and analgesia in the Accident and Emergency Department (AED), on-going haemodynamic resuscitation, dealing with trauma associated coagulopathy, preoperative optimization, ventilatory strategies, intensive care monitoring, and rehabilitation including pain management.^{5, 6, 7} Surgeons have an important role and are emphasized for definitive and supportive surgical interventions. Additional support for management from other team members like a physiotherapist, nursing staff, technicians, blood bank, microbiologist, and family as well is paramount for a successful outcome.^{8, 9, 10} The management of polytrauma patients can be challenging due to multi-organ involvement, occult injuries, limited information about patient history, evolving physiological derangements, presence of acute pain, limited time available to stabilize the patient in the pre-operative period. This review provides an insight into the management of trauma victims from a team approach perspective with a focus on perioperative anaesthetic concerns.

1.1. Anaesthetic consideration in the management of polytrauma patients

• 1Analgesia and sedation in the emergency room and diagnostic procedures
• 2Regional Anaesthesia in Trauma patients
• 3Role of Sedation in trauma patients
• 4Anaesthetic management
• 5Preparation of the operating room (OR).
• 6Haemodynamic management in trauma patients
• 7Critical care management in the polytrauma
• 8Chronic pain following trauma

1.1.1. Analgesia and sedation in the emergency room and diagnostic procedures

Patients with trauma usually have acute pain and its severity depends on the extent of the injury. Early and effective treatment of pain is necessary to ensure patient co-operation for examination, diagnostic and bedside procedures, optimal positioning during anaesthesia, reduction in disability as well as shorter recovery time. Inadequate pain management leads to decreased productivity and poor quality of life. Oligoanalgesia is a risk factor for the development of chronic pain with a significant effect on productivity and quality of life.^{11, 12, 13} But pain is often overlooked especially in an unstable patient with only 35.7% of patients receiving analgesics and 12.5% receiving adequate pain management in the emergency department.¹⁴ Numerous factors must be considered while choosing analgesics which include the efficacy of analgesic, ease of use, onset and duration of action, safety and tolerability, contra-indications, the severity of pain, and the potential for drug interaction.¹⁵ A systematic review and meta-analysis regarding the use of analgesics in trauma patients in the emergency room concluded that opioids such as morphine and fentanyl, N-methyl-d-aspartate receptor (NMDA) receptor antagonist ketamine were suitable as analgesics in trauma patients breathing spontaneously in the presence of appropriate monitoring and expertise in emergency procedures.¹⁶ A thorough patient assessment including neurological, respiratory, and cardiovascular systems is required. Assessment of pain using pain scores like visual analogue scale (VAS), or numerical rating scale (NRS) to decide the drugs and modality of the analgesic approach is needed. Various drugs such as opioids, ketamine, dexmedetomidine, acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs), and lignocaine is available in an anaesthesiologist’s armamentarium. But each drug has its advantages, disadvantages, and limitations and therefore the choice of drugs and analgesic approach needs to be individualized. Opioid medications, although provide good analgesia, can cause respiratory depression, sedation, nausea, vomiting, and other side-effects which could be detrimental or have an adverse impact on the assessment of the trauma patients. Also, there have been concerns regarding the opioid crisis associated with these drugs. NSAIDs must be used sparingly due to the presence of coagulopathy and rhabdomyolysis in trauma patients. Dexmedetomidine provides good analgesia without respiratory depression but can cause bradycardia and hypotension. Recently, MEDITA (Methoxyflurane in the emergency department in Italy) trial (phase 3b) that compared standard analgesic treatment [intravenous (IV) morphine 0.1 mg/kg for severe pain (NRS ≥ 7); IV paracetamol 1 g or IV ketoprofen 100 mg for moderate pain (NRS 4–6)] with the efficacy and safety of methoxyflurane for acute pain in trauma concluded that in patients with moderate to severe pain methoxyflurane provided better analgesia than standard analgesic treatment and could be an effective and faster non-opioid treatment modality.¹⁷

1.1.2. Regional Anaesthesia in Trauma patients

Multi-modal analgesia that combines the use of non-opioid analgesics and regional analgesic techniques provides superior analgesia and reduces the need for opioid analgesics. Regional anaesthetic and analgesic techniques have been increasingly used in acute trauma patients. The use of ultrasound has led to increased safety and utility of regional techniques both as an analgesic technique in an emergency as well as for providing anaesthesia during surgeries. It provides rapid relief of acute pain and dense anaesthesia to the specific injured part being more effective than opioids and sedatives.^18,19 Regional techniques include neuraxial blocks, peripheral nerve blocks, non-neuraxial truncal blocks such as erector spinae, paravertebral, serratus anterior plane (SAP), quadratus lumborum, transversus abdominis plane (TAP), rectus abdominis plane block, liposomal bupivacaine infiltration, etc (Table 1). The advantage of these regional techniques is superior analgesia with lesser adverse events, keeping a patent airway, reduced opioid requirement in case any intervention is required, reduced need for monitoring, and faster recovery. They allow reassessment for any neurological insult, quicker triage, and earlier readiness for transportation. The advantages and disadvantages associated with regional techniques have been described in Table 2.

Table 1.

Advantages and disadvantages of regional techniques.

Regional technique	Advantages	Disadvantages
Peripheral nerve blocks (PNB)	➢ Excellent analgesia ➢No hemodynamic disruption or respiratory depression ➢Decreased incidence and severity of chronic post-traumatic pain syndrome20,21 ➢Improved surgical  Outcome.22 ➢Decreased vasospasm and improved vascular flow	➢Need for optimal positioning ➢Need for equipment, time, and space ➢Preparation for recognizing and treating LAST ➢Primary survey and early resuscitation gain priority ➢Adequate training and experience needed ➢The presence of coagulopathy precludes the use of PNB
Neuraxial blocks	➢Good analgesia ➢Reduced need for opioids (opioid-sparing effect) ➢Lesser pulmonary and cardiac complications ➢Facilitates physiotherapy ➢Reduces stress response ➢Avoids airway manipulation	➢Hemodynamic instability, coagulopathy, neurological deficits, elevated intracranial pressure precludes their use ➢Careful consideration in trauma patients in need of therapeutic thromboprophylaxis ➢Need for patient positioning ➢Greater monitoring and time

1.2. On arrival block in trauma patients

Performing “on arrival block” helps in providing immediate relief of pain in trauma patients and facilitates further examination, positioning for performing neuraxial blocks and surgery, minor procedures in the emergency department. Pericapsular nerve block (PENG) performed in five patients with hip fracture as on arrival block to facilitate positioning and for perioperative analgesia provided good pain relief within 10–15 min of the block.²³ A study comparing peripheral nerve block with analgo-sedation in 18 patients with isolated extremity injury concluded that patients who received peripheral nerve block had lower pain scores with reduced pain severity during pre-hospital medical interventions such as reduction, splinting as compared to those who received analgosedation (midazolam with ketamine or fentanyl).²⁴

Special considerations for the use of regional techniques in trauma patients –

• 1.Difficulty in obtaining consent due to impaired consciousness and impaired judgment due to substance use, iatrogenic cause, and others.
• 2.Performing regional techniques in patients with impaired consciousness can increase the risk of neural injury.
• 3.Difficulty in obtaining optimal patient position required for these techniques
• 4.Resuscitation of the patient gains priority over performing regional blocks for pain management.
• 5.The presence of coagulopathy which could be due to trauma, the use of anticoagulants, unknown medical history increases the risk of bleeding/hematoma formation after neuraxial techniques, and deep blocks. There is insufficient evidence regarding the safety of peripheral nerve blocks in patients on antiplatelet and anticoagulants.
• 6.Presence of nerve injury that increases the theoretical concern of permanent nerve injury.
• 7.Increased risk of infections.
• 8.Concerns regarding the masking of symptoms of compartment syndrome with the use of PNB.

Some of these concerns could be addressed by various approaches such as obtaining informed consent from surrogate if benefits outweigh the risks, use of ultrasound, considering fascial plane blocks and truncal blocks, avoidance of neuraxial and para neuraxial techniques until coagulation status is confirmed, prior discussion with the trauma team regarding the need for DVT prophylaxis and therapeutic anticoagulation, documenting the neurological examination findings, avoidance of PNB at pre-existing nerve injury sites, using low dose and short-acting local anaesthetics, regular examination of PNB catheter sites and use of aseptic precautions.

1.2.1. Role of Sedation in trauma patients

Procedural sedation is needed in trauma patients during diagnostic imaging and painful procedures such as closed reduction of fractures to alleviate anxiety while maintaining a patent airway. It should ensure patient safety, increase the success of procedure while returning the patient to the pre-sedation state. It should be administered only by skilled, trained personnel capable of providing resuscitation and airway management. No single agent is ideal, and it needs to be individualized as per the procedure, its duration, American Society of Anaesthesiologists (ASA) physical status of the patient, hemodynamic stability, associated cardiorespiratory, and airway compromise, and adverse effects of the drugs (Table 3).

Table 2.

Drugs and Pharmaceuticals to provide sedation in Trauma patients.

Drug	Dose	Onset of action	Duration of action	Advantages	Disadvantages
Midazolam	0.05–0.2 mg/kg i.v	Within 5 min	20 min	Anxiolysis spasmolytics amnesia	No analgesia Respiratory depression (Hypoventilation, hypoxemia, apnoea)
Propofol	0.5–1 mg/kg i.v bolus; repeated at a dose of 0.25–0.5 mg/kg every 3–5 min Infusion-100-150mcg/kg/min	15–30 s	3–10 min	Anxiolysis amnesia	No analgesia Hypotension Respiratory depression
Ketamine	1–2 mg/kg i.v	60 s	5–10 min	Analgesia Amnesia	Emergence delirium Increased intracranial, intra-ocular pressure Increased secretions Tachycardia
Etomidate	0.1–0.2 mg/kg i.v	<60 s	5–10 min	Anxiolysis Maintains hemodynamic stability	No analgesia Myoclonus Adreno-cortical suppression Nausea, vomiting
Dexmedetomidine	0.5-1 mcg/kg i.v over 10 min Infusion-0.2-0.7 mcg/kg/hr.	3–5 min	15 min	Sedation Analgesia No respiratory depression	Hypotension Bradycardia Dryness of mouth
Ketofol	0.5–0.75 mg/kg of both agents	30–60 s		Analgesia Sedation Amnesia Lesser agitation Shorter induction and recovery time	Respiratory depression Vomiting Bradycardia Emergence (lesser extent)
Fentanyl	1-1.5mcg/kg followed by 1 mcg/kg every 3 min	1–2 min	30–60 min	Rapid onset of action Shorter duration of action Less constipation	Pruritus Nausea, vomiting Respiratory depression Chest wall rigidity (high doses)

AbbreviationsIntravenous = i.v; Kilogram = kg; microgram = mcg; milligram = mg

Table 3.

Different peripheral nerve, nerve plexus, myo-fascial plane blocks used in trauma patients.

Site of trauma	Block	Advantages	Special considerations
Upper extremity	Brachial plexus (supraclavicular, infraclavicular, Axillary) Median, radial and ulnar nerve blocks Intravenous regional anaesthesia (Bier’s block)	➢Provides rapid analgesia ➢Facilitates surgery ➢Provides immobilization of repaired structures along with regional sympathectomy ➢Facilitate closed reduction ➢Individual nerve block provides selective analgesia and help to preserve motor function	➢Hemidiaphragmatic paralysis can further compromise respiratory function ➢Horner’s syndrome (interscalene block) may complicate the recognition of brain injury ➢Positioning may be difficult due to pain
Lower extremity	Lumbar/sacral plexus block, compartment block (Fascia Iliaca), femoral nerve block, lateral femoral cutaneous block, adductor canal block, sciatic nerve block, ankle block, quadratus lumborum block	➢Good analgesia -facilitates positioning ➢Patient co-operation for further examination ➢Facilitates diagnostic procedures and minor surgical procedures	➢Risk of coagulopathy in deeper plane blocks ➢Multiple injections (ankle block) ➢Increased risk of fall if quadriceps is blocked -patients need to be counselled ➢Compartment syndrome could be masked
Anterior chest wall, axilla and distal clavicle	Pectoral block (Pecs 1 and 2) Serratus anterior plane block Erector spinae block Intercostal block Intrapleural block	➢Useful in chest tube placement, rib fractures, clavicle fractures, posterior and lateral injuries ➢Easier to perform ➢Catheter insertion for continuous analgesia possible ➢Can be performed in patients with coagulopathy ➢Minimal hemodynamic derangements (intrapleural analgesia) ➢No motor weakness	➢Intercostal block -less effective in major chest trauma and thoracotomy ➢Multiple injections (intercostal block)- risk of Local Anaesthetic Systemic Toxicity, risk of pneumothorax ➢Intrapleural analgesia unreliable ➢Limited data in trauma patients
Unilateral chest injury	Paravertebral block	➢Good unilateral analgesia ➢Segmental dermatomal block – less hypotension compared to thoracic epidural ➢Similar coverage as with epidural	➢Risk of pneumothorax (although less with the use of ultrasound) ➢Coagulopathy and hematoma formation ➢Epidural spread
Anterior abdominal wall	Rectus sheath block Transversus abdominis plane block Ilioinguinal/iliohypogastric	➢Avoids adverse effects of neuraxial block ➢Superficial block and compressible	➢Data available in trauma patients limited ➢Visceral plane is not covered ➢Tissue plane may be distorted
Low thoracic to hip	Quadratus lumborum	➢Can be administered in supine position ➢Visceral pain may be covered ➢Supra and infra-umbilical, femoral and acetabular neck may be covered	➢Limited data ➢Risk of renal and colon injury, retroperitoneal hematoma

ASA standard monitoring such as the electrocardiogram (ECG), pulse oximetry, non-invasive blood pressure (NIBP), capnography along with emergency airway management and resuscitation equipment must be readily available before providing procedural sedation. Supplemental oxygen should be provided throughout the procedure. These agents can also be used in combination with the synergistic effect and reduction of side effects. Various sedation scales such as the Ramsay sedation scale, Richmond Agitation Sedation (RAS) Scale, Observer’s Assessment of Alertness/Sedation Scale (OAASS) can be used to monitor the patient response. Guidelines have been provided by ASA, the American College of Emergency Physicians (ACEP) for the safe conduct of procedural sedation.^25,26

1.2.2. Anaesthetic management

The anaesthetic management of a trauma patient can be challenging due to the limited history available regarding co-morbidities, medications, allergies, presence of hemodynamic instability, occult injuries, airway injuries, and limited time available for optimization of co-morbidities. Despite time constraints, all the relevant history should be obtained along with a thorough airway assessment and a quick physical examination. Pre-anaesthetic evaluation of these patients should always begin with airway, breathing, and circulation. Mental status, focal neurological signs, heart sounds and breath sounds, arterial pressure, pulse rate, airway assessment, skin colour (pallor, icterus, cyanosis) should be assessed and documented. The nature and extent of injuries should be determined along with the surgeon. Various trauma scoring systems such as Injury Severity Score (ISS), Abbreviated Injury Scale, Revised trauma score, Acute physiology, and chronic health evaluation score (APACHE) and others can be used for the purpose.

The procedure to be performed on an emergent basis and the procedure that could be postponed until the patient is stable has to be decided by the trauma management team including the trauma surgeon, anaesthesiologists, and emergency physician.²⁷ Preoperative investigations such as complete blood count, chest x-ray, lateral x-ray cervical spine, ECG, focused abdominal ultrasound, coagulation profile, electrolytes should be obtained if possible. Blood grouping and cross-matching should be obtained, and the availability of adequate blood should be ensured.

1.2.3. preparation of the operating room (OR)

The trauma OR needs to be kept ready for the trauma victims. Apart from routine OR related arrangements, certain specific preparations are required for perioperative management of trauma patients for surgical intervention. The OR should be warmed to 26–28 °C before shifting the patient. Ensure the presence of adequate fluids (colloids and crystalloids), fluid warmers, rapid infusion sets, drugs including vasopressors and inotropes, blood and blood products, cell saver, forced air warmer, difficult airway cart. Emergency drugs and airway carts should be ready. The patient should always be transported with supplemental oxygen and proper monitors and ensured that the cervical spine is cleared, or the neck is stabilized before transporting the patient.

A good intravenous (IV) access with two 14G cannulas should be obtained. American Society of Anaesthesiologists (ASA) standard monitoring (ECG, Human Non-invasive Blood Pressure (NIBP), capnography, pulse oximetry, core temperature) should be used. Urine output monitoring needs to be done as it is an indicator of end-organ perfusion. Invasive blood pressure monitoring, non-invasive cardiac output monitor, central venous access use is indicated in hemodynamically unstable patients, presence of co-morbidities, complex surgical procedures with expected massive blood loss, and fluid shifts. Use of point of care coagulation monitors such as thromboelastography (TEG), rotational thromboelastography (ROTEM) will help to guide the use of blood products and drugs such as antifibrinolytics.

Airway management can be challenging in the presence of facial and neck trauma. The presence of spinal cord injury, blood, secretions, tissue oedema, a full stomach, head injury, laryngeal injury, urgency of the situation further complicates the situation. Manual in-line stabilization of the cervical spine although controversial should be maintained all time during laryngoscopy and intubation or a hard-cervical collar should be used. If the base of the skull fracture is suspected, nasotracheal intubation should be avoided. Difficult airway cart with a fibreoptic bronchoscope, video laryngoscopes with different blades, laryngoscopes with various size blades, surgical cricothyroidotomy set, different size endotracheal tubes, airways, bougie, stylet, second-generation supraglottic airway device, tracheostomy set, transtracheal jet ventilation should be readily available and checked. An experienced anaesthesiologist should be preferably involved in securing the airway. An alternative airway management plan should be readily available. ASA has provided a difficult airway algorithm modified for trauma.²⁸ Proper pre-oxygenation should be done before the induction of anaesthesia and airway management along with oxygen supplementation throughout the period of airway management.

The anaesthetic technique used during the surgery depends on the type of surgery, duration of surgery, hemodynamic status of the patient, and presence of a full stomach. In the case of general anaesthesia rapid sequence intubation (RSI) is preferred. The anaesthesia induction agent should be used in small doses and titrated to the response. Severe hypotension can result in the use of propofol and thiopentone and hence must be used in small doses. Etomidate can be used in hemodynamically unstable patients, but it can cause adrenocortical suppression and myoclonus.²⁹ It has minimal cardiovascular and respiratory depressant effects with favourable effects on cerebral perfusion and cerebral oxygen supply-demand ratio at a dose <0.25 mg/kg. Ketamine is also used in trauma patients as an induction agent but in patients with severe shock, the cardiac depressant effect can get unmasked leading to cardiovascular collapse.³⁰ Rocuronium is the preferred neuro-muscular blocking agent during RSI. Fentanyl is the preferred opioid in these patients. Maintenance of anaesthesia can be done using low concentration volatile anaesthetic, total intravenous anaesthesia, opioid, and neuromuscular blocking drugs. Volume resuscitation needs to be continued to prevent vascular collapse.

Regional anaesthetic techniques can be considered as the sole technique or combined with general anaesthesia depending on the surgery, hemodynamic status of the patient, presence or absence of coagulopathy, and sepsis. Regional techniques are useful at it does not interfere with airway patency, attenuates stress response, preserves bowel function, no interference with neurological status. It facilitates patient positioning, painful procedures, patient transport, improves blood flow, provides greater patient comfort, reduces the risk of opioid tolerance and abuse, a positive impact on chronic pain, decreases the post-operative delirium and stress response, decreased ICU and hospital length of stay and decreased cost.³¹ Hence, regional techniques should be a part of perioperative patient management whenever feasible. A Cochrane review on the benefits of nerve blocks in patients with hip fractures concluded that femoral nerve block provided good analgesia reducing opioid requirements pre-operatively and during surgery.³² A study comparing general anaesthesia with low dose ultrasound-guided axillary block in upper extremity surgery reported reduced opioid consumption, good analgesia, and anaesthesia, shorter time to recovery with earlier discharge from hospital in patients who received ultrasound-guided axillary block.³³

1.2.4. Haemodynamic management in trauma patients

Hemodynamic compromise may occur in the trauma victim and its severity is based on the mechanism of injury, the systemic insult and organs involved, whether the patient is a responder, non-responder, or transient responder to initial resuscitation. Continuous monitoring of the volume status should be done with adjustment of fluid therapy according to the need. Initial resuscitation involves the administration of 1 L of balanced warm crystalloids.

Damage Control Resuscitation (DCR) is an accepted strategy for the management of trauma victims and the primary principle includes permissive hypotension, Hemostatic resuscitation, and damage control surgery.³⁴ Permissive hypotension involves the restriction of fluid administration until surgical control of haemorrhage while allowing sub-optimal organ perfusion for a limited duration while resuscitation and damage are being managed. The threshold systolic blood pressure of 80–100 mmHg is acceptable in otherwise normotensive patients. Hemostatic resuscitation involves early administration of blood and blood products as primary resuscitation fluid to prevent the development of dilutional coagulopathy and treat acute traumatic coagulopathy. TEG and ROTEM help in early recognition of coagulopathy. Packed red blood cells (PRBC), fresh frozen plasma (FFP), and platelets should be transfused in 1:1:1 ratio. Hypothermia, acidosis, and hypocalcaemia should be prevented. Recombinant factor VIIa (rVIIa), cryoprecipitate, fibrinogen concentrates need to be used when appropriate. Damage control surgery has been established as a standard of care in trauma patients with severe injury and performed to control the haemorrhage, minimize the contamination along with temporary abdominal closure. Prevention of the lethal triad -hypothermia, acidosis, and coagulopathy is of utmost importance in trauma patients. Massive blood transfusion can result in hypocalcaemia which should be treated with the administration of calcium gluconate/chloride which also helps to correct hypotension associated with hypocalcaemia.³⁵ Higher mortality has been reported with the use of vasopressors in trauma patients.³⁶ Vasopressin bolus (5–10 units) followed by an infusion (0.04U/min) can be tried in refractory hypotension together with aggressive blood and blood product administration.

Massive blood transfusion involves a replacement of 50% of the total blood volume in 3 h or entire blood volume in 24 h. These protocols will help to improve survival, reduce errors, reduces the wastage of resources, and ensure timely delivery of the blood products. Identification of patients who might require massive transfusion would help in better planning. Truncal haemorrhage with proximal amputation, multiple proximal amputations, laceration of liver, pelvic fracture, the evisceration of abdominal organs with hypotension are some of the predictors of massive transfusion.³⁷

A hypercoagulable state can be seen in severely injured and is termed “Acute Coagulopathy of Trauma-shock”. Numerous factors may contribute to the pathogenesis of this coagulopathy. Hypoperfusion following trauma causes increased anticoagulation and hyperfibrinolysis by an increase in protein C, tissue plasminogen activator production, and decrease in plasminogen activator inhibitor and thrombin activatable fibrinolysis inhibitor.⁶ Those patients with a combination of ISS (Injury Severity Score) score greater than 25, pH < 7.10, temperature < less 34 °C, and systolic blood pressure <70 mmHg have a 98% likelihood of developing life-threatening coagulopathy.³⁸ The decision of tracheal extubation or shifting the patient to a critical care unit with tracheal tube in-situ is determined by various factors such as duration of surgery, hemodynamic and metabolic status, arterial lactate level, preoperative cardiac and pulmonary status, intraoperative blood loss, and transfusion.

1.2.5. Critical care management in the polytrauma

In the critical care unit, resuscitation should be continued to correct the physiological changes and the metabolic consequences of haemorrhagic shock. Volume resuscitation, correction of coagulopathy and acidosis, prevention or treatment of hypothermia should be instituted. Parameters such as urine output, the output from drains and nasogastric tube, blood lactate levels, and changes in blood pressure, heart rate may be used to guide fluid therapy. Non-invasive cardiac output monitors that use dynamic indices can also be used to guide fluid therapy. Fluid therapy should prevent visceral oedema and minimize volume overload to improve the outcome of primary fascial closure. Also, attention should be focused on analgesia, nutritional status, and respiratory mechanics. Patients need to be closely monitored for recurrent abdominal compartment syndrome and ongoing surgical bleeding for early re-exploration. The physiological changes should be optimized as an open abdomen can delay the extubation and increase the risk of entero-cutaneous fistulae. Active re-warming should be continued. The goal in these patients should be to obtain a core temperature of 37 0C within 4 h of admission to the critical care unit.³⁹ The goal of correcting coagulopathy is to obtain a prothrombin time (PT) < 15, platelet counts >100 k, and fibrinogen >100.⁴⁰

The endpoints of resuscitation include hemodynamic stability without the need for vasopressors, lactate <2 mmol/L, normal coagulation, normoxia, normocarbia, normothermia, and urine output>1  mL/kg/h. Dyselectrolytemia, hyperglycaemia should be corrected. Low volume lung ventilation is preferred.⁴¹ Infective complications may occur and a low threshold for escalation to higher antibiotics must be followed.

1.2.6. Chronic pain following trauma

Chronic pain following trauma can be of different types –

• 1Complex Regional Pain Syndrome
• 2Phantom limb pain
• 3Post-traumatic abdominal pain
• 4Spinal cord injury pain
• 5Pain due to traumatic brain injury
• 6Pain due to vertebral fracture
• 7Persistent post-surgical pain

Any patient presenting with pain following trauma needs to be evaluated with proper history and examination. The history should include relevant medical, surgical history, and pain description. Questionnaires such as Mc Gill pain questionnaire -short form can be used for this purpose.

1.3. Complex Regional Pain Syndrome (CRPS)

CRPS is a painful and disabling disorder that affects the extremities and shows signs of vasomotor, sudomotor, inflammatory, and trophic changes in the affected extremity along with severe, continuous pain. It is of 2 types - CRPS 1 and CRPS 2. CRPS 1 has no nerve lesion which is demonstrable while CRPS 2 has a nerve lesion which can be demonstrated. The exact pathophysiology is not known and both central and peripheral mechanisms are proposed to play a role in the initiation and maintenance of CRPS. Inflammatory response, neurogenic inflammation, genetics, cortical reorganization, deep tissue microvascular ischemia-reperfusion injury, and psychological factors are the various pathogenic mechanisms that have been proposed to be involved in CRPS.⁴² The diagnosis is mainly based on history and physical examination.

Treatment options for CRPS are limited. Physiotherapy can help to reduce pain. Medications used should follow the most prominent mechanism that has been deemed to have caused CRPS. Immunomodulating drugs such as glucocorticoids, thalidomide, TNF-alpha antagonists have been tried but have not been accepted as the standard of care due to insufficient and conflicting evidence.⁴³

World Health Organisation (WHO) analgesic ladder can be used to treat the pain in CRPS. Neuropathic pain can be treated using gabapentin. Low dose IV ketamine can be tried in refractory pain, but the exact dose is not clear. Calcium channel blockers, phosphodiesterase 5 inhibitors, alpha-blockers can be tried on a short-term basis in the presence of vasomotor symptoms but should be stopped in the absence of benefit.⁴⁴

Interventional modality such as spinal cord stimulation can be considered in refractory cases and has a positive effect on vasomotor symptoms and somatosensory system due to multiple mechanisms of action.⁴⁵

1.4. Persistent post-surgical pain

Pain that lasts for more than two months after surgery in the absence of alternative causes that includes any other chronic condition causing pain and infection of chronic nature.⁴⁶ Preoperative pain, genetics, preoperative opioid use, psychological factors, inadequate control of acute postoperative pain, nerve injury caused during surgery, perioperative use of a high dose of remifentanil leading to opioid-induced hyperalgesia, inflammatory response via monocyte recruitment are some of the risk factors implicated in the development of persistent post-surgical pain.^47,48 Various drugs and techniques such as ketamine, gabapentinoids, clonidine, dexmedetomidine, anti-inflammatory drugs, regional anaesthesia, and local anesthetics have been tried in the prevention of chronic postoperative pain with varying results and no conclusive evidence.^{49, 50, 51, 52, 53, 54}

1.5. Future direction

The beneficial effects of regional blocks have been studied in surgeries such as breast, cholecystectomy, spine surgeries, and others but there is a paucity of literature (randomised trials, systematic reviews, and meta-analysis) on outcomes specific to trauma patients for the length of hospital stay, surgical outcomes, development of chronic pain and opioid dependence. Hence, this could provide a potential topic of interest for research in the future. Enhanced Recovery After Surgery remains a proven modality for various surgeries but needs to be extended to trauma surgery. This needs further research for its utility and various specific intervention needed for the same.

2. Conclusion

Anaesthesia for trauma patients can be challenging but a multi-disciplinary approach with proper planning and communication among the trauma team can help to improve the outcome. The extent of the injury, resuscitation status, co-morbidities need to be considered while planning for perioperative management. The role of anaesthesiologists is crucial in the management of trauma patients and begins in the emergency room resuscitation and continues in the perioperative period and beyond as in chronic pain management.

Author’s contributions

RD and RG involved in Conceptualization, literature search, review, and editing. VJ and KPI involved in literature search, writing, editing, drafting, RV writing, editing, drafting of the manuscript. RV supervised the study. All authors have read and agreed on the final draft submitted.

Disclosure

None.

Source of Funding

None

Funding of the study

No funding was involved in this study

Declarations of competing interest

The authors declare No conflict of interest.