309 SEDATION Monitoring during IV sedation Ensure patients given IV sedation receive O 2 , pulse oximetr y monitoring and have a venous cannula. Monitor ECG. Antagonists The speci \201 c antagonists \202 umazenil (for benzodiazepines) and naloxon e (for opioids) must be available immediately, but should be needed very rarely. If respira tory depression occurs, standard techniques to maintain the airway and breathing are more i mportant than giving antagonists. Flumazenil and naloxone have shorter durations of action than the drugs they antagonize, so careful observation is essential if either drug is used. Recovery and discharge after sedation If IV sedation is used, monitor the patient carefully until recovery is complete. Monitoring and resuscitation equipment and drugs must be available. Minimum criteria for discharging a patient are: \200 Stable vital signs. \200 Ability t o walk without support. \200 Toleration of oral \202 uids and minimal nausea. \200 Ad equate analgesia. \200 Adequate supervision at home by a responsible adult. Instruct the patient (both verbally and in writing) not to drive, operate machinery, make any important decisions or drink alcohol for 24 hours. Arrange appropriate follow-up. Ensure the adult ac companying the patient knows who to contact if there is any problem. Sedation in children Many children (and their parents and staff) are distressed by proce- d ures such as suturing of minor wounds under LA. Sedation is helpful to prevent distress and allows procedures to take place with minimal physical restraint. Sedation may be given by oral or nasal routes, IM or IV. Pediatric IV sedation requires anesthetic experience becaus e of the narrow therapeutic margin between sedation and anesthesia. Ketamine given IM in a dose of 2 \200\2232.5mg/kg is currently the method of choice for ped iatric sedation in the ED by doctors with appropriate training ( b p.278). This dose of ket amine does not provide full anesthesia and so local anesthesia is required for cleaning and suturing of wounds. Oral midazolam is advocated by some specialists. Oral sedation with promethazine is not adv isable, since it is often ineffective. 310 CHAPTER 7 Analgesia and anesthesia General anesthesia in the emergency department GA may be needed in the ED for many differen t conditions: \200 Minor surgery (eg drainage of abscesses, manipulation of fractures). \200 Cardioversion. \200 Airway problems (eg facial trauma, burns, epiglottitis). \200 Respiratory failure (eg asthma, chronic obstructive airways disease, pulmonary oedema, chest injuries). To protect the airway and control ventilation after head injuries and to keep the patient immobile for a CT scan. To protect the airway and maintain ventilation in status epilepticus unresponsive to standard drug therapy. Immediate major surgery (eg thoracotomy or laparotomy for trauma, ruptured ectopic pregnanc y or aortic aneurysm). If at all possible take the patient to the operating theater before anesthesia, as the loss of sympathetic tone after the onset of anesthesia can cause catastr ophic hypotension in a hypovolaemic patient. In extreme emergencies, it may be necessary to operate in the ED. GA in the ED tends to be stressful for the anesthetist and potentially hazardous for the pa tient, who is usually unprepared for anesthesia, with a full stomach and increased risk of aspiration. GA should only be given by doctors with anesthetic training, but other staff sh ould know what is required so they can help when necessary. Pre-operative assessment This is essential for safe anesthesia. If time allows, assess the patient before contacting the anesthetist to arrange the anesthetic. However, if emergency anesthesia is needed, call the anesthetist immediately so that he/she can come and assess t he patient, and get senior help if necessary. A checklist of questions to ask before GA is shown opposite. Fitness for GA The American Society of Anaesthesiologists (ASA) classi \201 - cation of pr e-operative \201 tness is widely used by anesthetists: 1 Healthy patient with no systemic disease. 2 Patient with a mild to moderate disease which does not limit their activity in any way (eg treated hypertension, mild diabetes, smoker). 3 Patient with a severe systemic disturbance from any cause which limits activity (eg IHD with d exercise tolerance, severe COPD). 4 Patient with a severe systemic disease which is a constant threat to life (eg severe chronic bronchitis, advanced liver disease). 5 Moribund patient who is unlikely to survive 24 hours with or without treatment. The risk of complications from GA correlates well with ASA group. Only patients in ASA grou ps 1 and 2 should be given an elective anesthetic by a junior anesthetist in the ED. Childr en aged <7 years should not usually have a GA in the ED, except in an emergency. 311 GENERAL anesthesia IN THE EMERGENCY DEPARTMENT Pre-operative investigations No investigation except \200\230dipstick \200\231 urinalysis is needed, unless pre-operative assessment reveals a problem. Measure Hb in any patient who appears anemic. Check for sickle cell disease in any patient of Afro-Caribbean, Cypriot or Indian origin. Measure U&E in patients on diuretics, and blood glucose in diabetics. ECG a nd CXR are not needed, unless clinically indicated. Perform a pregnancy test if pregnancy i s possible. Checklist for pre-operative assessment in the ED Age. \200 Weight. \200 Time of last drink. \200 Time of last food. \200 Drugs. \200 Drugs given in the ED. \200 Time of last analgesia. \200 Allergies. \200 Sickle cell risk? \200 Infection risk? \200 Family history of GA problems? \200 Is the pati ent expected to go home after recovery from anesthetic? \200 Is there a responsible adult who can look after the patient at home? Airway problem? \200 Dentures/crowns/loose teeth? \200 Chest disease? \200 Smoker? \200 Cardiac disease? \200 Blood pressure. \200 GI problem? \200 Other illness? \200 Possibility of pregnancy? \200 Previous GA? (problems?) \200 Consent form signed? Preparation for GA Ideally, the patient should have nothing to drink for 4 hours and no foo d for 6 hours before anesthesia. Explain why this is necessary. Fasting does not guarantee an empty stomach. Trauma, pregnancy and opioids delay gastric emptying. If the patient is in pain, give analgesia and an antiemetic. Discuss with the anesthetist a ny other drug treatment that is required. Patients with a hiatus hernia or gastro-oesophage al re \202 ux need antacid prophylaxis (eg ranitidine 50mg IV and an antacid). Explain the proposed operation and anesthetic to the patient (and relatives if appropriate) and ensure valid consent is obtained. The patient must be clearly labeled with a wrist-ban d. Remove contact lenses, false teeth and dental plates. Recovery and discharge after anesthesia When the operation has \201 nished, place the pat ient in the recovery posi- tion and ensure continuous observation by trained staff until re covery is complete. The anesthetist should stay with the patient until conscious- ness is r egained and the airway is controlled. Monitoring and resuscitation equipment and drugs must be available. The minimum criteria for dis- charging a patient are the same as following s edation ( b p.309). Importantly, tell the patient (both verbally and in writing) not to dri ve, operate machinery, make any important decisions or drink alcohol for 24 hours. Arrange appropriate follow-up and make sure that the adult accompanying the patient knows who to co ntact if there is a problem. 312 CHAPTER 7 Analgesia and anesthesia Emergency anesthesia and rapid sequence induction Emergency anesthesia and intubation are o ften needed to protect the airway and provide adequate ventilation in a patient with a head injury or multiple trauma. There is a high risk of aspiration of gastric contents into the lungs, so use a cuffed ET tube (uncuffed in small children). In a patient with a gag re \202 ex any attempt to intubate without anesthesia may cause vomiting and aspiration. Anest hesia before intubation is essential in head- injured patients to minimize the i in ICP. Rapid sequence induction (RSI) RSI involves administration of a sedative or induction agent virtually simultaneously with a neuromuscular blocking agent to allow rapid tracheal intub ation. RSI should only be performed by staff who have had speci \201 c training and experi ence in the techniques and the drugs used, and the recognition and management of possible p roblems . However, it is useful if ED staff who have not had such training understand the p rinciples of RSI, so that they can assist as needed. \200 Call for senior ED/anesthetic/I CU help. \200 Check all drugs and equipment, including suction, bag and masks, laryngosco pe (and spare with large blade), tracheal tubes and introducers, syringe and valve or clamp for ET tube cuff, connectors. \200 Check that the trolley can be tilted head-down easily . \200 Check monitoring equipment (ECG, BP, pulse oximeter, end-tidal CO 2 monitor). Explain the procedure to the patient if possible. \200 Assess the risks and any condition s which might cause problems with intubation (eg trauma to the face or neck, d mouth openin g, receding chin). Identify a back-up plan ( b p.314) and communicate this to the team. Establish monitoring (ECG and pulse oximetry) and secure IV access. \200 Protect the cerv ical spine in all trauma patients: an assistant should provide in-line immobilization durin g intubation. In other patients, use a pillow and position the head and neck to aid intubat ion. If possible, pre-oxygenate for 3min with 100 % O 2 via a tight- \201 tting mask, with the patient breathing spontaneously. If breathing is inadequate, ventilate for 2min on 100 % O 2 with a bag and mask, with an assistant applying cricoid pressure by pressing \201 rmly downwards with a thumb and index \201 nger on the cricoid cartilage, while supporting the patient \200\231s neck with the other hand. Give an induction agent (eg thiopental or etomidate) quickly to provide rapid anesthesia. C ricoid pressure must be maintained continuously until the airway is secure. Follow the induction agent immediately with a muscle relaxant (usually suxamethonium). Keep the face mask tightly applied until the anesthetic and relaxant are effective. Then intubate and in \202 ate the cuff quickly. 313 EMERGENCY anesthesia AND RAPID SEQUENCE INDUCTION Try to con \201 rm tracheal placement of the tube: ideally it will have been seen passing through the cords, but this may not be possible in an emergency intubation. Check air entry in both sides of the chest. Check end-tidal CO 2 (but this may be misleading if oesophagea l intubation occurs in a patient who has recently consumed antacids or \201 zzy drinks). If CO 2 is not detected, oesophageal intubation has occurred. Cricoid pressure can be released when the ET tube is correctly positioned, the cuff has bee n in \202 ated and ventilation is satisfactory. Secure the tracheal tube. \200 Continue observation and monitoring. 314 CHAPTER 7 Analgesia and anesthesia Dif \201 cult intubation Dif \201 culties with intubation may result from problems with t he equipment, the patient, the circumstances of intubation, and from lack of experience or skill. Equipment Proper working equipment must be available where intubation may be needed \200 \224 pillow, suction, laryngoscope (and spare) with interchange- able blades, ET tubes of d ifferent diameters (cut to suitable lengths, but with uncut tubes available), syringe and c lamp for cuff, connectors, \202 exible stylet, gum-elastic bougie, lubricating jelly, Mag ill \200\231s forceps, tape for securing ET tube. A face mask and ventilating bag, and oral /nasal airways must be immediately available. Laryngeal masks and cricothyroidotomy equipme nt must be accessible. Fiber-optic laryngoscopes are useful in skilled hands, but are not r outinely kept in EDs. The patient Patients may be dif \201 cult to intubate because of facial deformity or swell ing, protruding teeth, d mouth opening from trismus or trauma, d neck movement or instabili ty of the cervical spine, epiglottitis or laryngeal problems, tracheal narrowing or deviati on, blood, vomit or FB in the airway. Circumstances and skills Intubation is much easier in the controlled environment of an oper ating theater than in an emergency in the ED or in pre-hospital care. Skilled help is vital \200\224 in-line immobilization of the neck, cricoid pressure, and assistance with equipm ent and cuff in \202 ation are needed. Practice intubating manikins regularly. Practical points Before attempting intubation, oxygenate by bag and mask ventilation. Take a deep breath as you start intubation \200\224 if the patient is not intubated successfull y when you have to breathe again, remove the ET tube and laryngoscope, and ventilate with O 2 for 1 \200\2232min using a bag and mask before making another attempt. Consider adjustin g the patient \200\231s position, using a different size of laryngoscope blade or ET tube o r a stylet or bougie. Cricoid pressure can help by pushing the larynx backwards into view. The BURP maneuver (Backwards Upwards Rightwards Pressure on the thyroid cartilage) may be u seful in a dif \201 cult intubation. Oesophageal intubation Fatal if unrecognized. The best way of con \201 rming tracheal intu bation is to see the ET tube pass between the vocal cords. Inadvertent oesophageal intubati on can produce misleadingly normal chest movements and breath sounds. End-tidal CO 2 measur ement helps to con \201 rm tracheal intubation, but end-tidal CO 2 can be misleadingly i i n patients who have taken antacids or \201 zzy drinks. If in doubt, remove the ET tube an d ventilate with bag and mask. 315 DIFFICULT INTUBATION Failed intubation drill Persistent unsuccessful attempts at intubation cause hypoxia and i risk of aspiration and damage to teeth and other structures. If three attempts at intubatio n are unsuccessful, follow a failed intubation drill: \200 Inform all staff that intubati on attempts have ceased and get senior help. Ventilate the patient on 100 % O 2 using bag and mask, and an oral or nasal airway, while an assistant maintains cricoid pressure. If ventilation is impossible, turn the patient onto the left side and tilt the trolley head down, while maintaining cricoid pressure. If ventilation is still impossible release crico id pressure slowly and attempt to ventilate again. A laryngeal mask airway (LMA) can be very useful in this situation but requires training. P ractice the technique of LMA insertion on manikins and on patients in the operating theater whenever possible. Cricothyroidotomy ( b p.326) is rarely needed, but must be performed promptly if necessary. In non-emergency cases, the patient can be allowed to wake up, but this is not an option in a life-threatening emergency. Discuss the problem with a senior anesthetist. Warn the patient and GP if the dif \201 culty with intubation is liable to recur. Laryngospasm Laryngospasm occurs when the laryngeal muscles contract and occlude the airway , preventing ventilation and causing hypoxia. Causes \200 Stimulation of the patient during light anesthesia. \200 Irritation of the airway by secretions, vomit, blood or an oropharyngeal airway. Irritant anesthetic vapors. \200 Extubation of a lightly anesthetized patient. Treatment \200 Give 100 % O 2 . \200 Clear the airway of secretions, using gentle suction. \200 Gently ventilate the patient using a bag and mask. Over-in \202 ation is liable to \201 ll the stomach and cause regurgitation. Monitor the ECG for bradycardia or arrhythmias. In severe laryngospasm, an experienced anes thetist may consider deepening anesthesia or giving suxamethonium to allow intubation, or v entilation with a bag and mask. In a hypoxic patient, suxamethonium may cause bradycardia r equiring treatment with atropine. 316 CHAPTER 7 Analgesia and anesthesia General anesthetic drugs GA should only be given after anesthetic training. IV anesthetic i nduction agents are used for induction of anesthesia, as the sole drug for short procedures (eg cardioversion), for treatment of status epilepticus unresponsive to other anticonvulsa nts ( b p.149), for total IV anesthesia and for sedation of a ventilated patient. They are particularly hazardous in patients with upper airway obstruction or severe hypovolaemia. Th iopental, etomidate and many other drugs are unsafe in acute porphyria (see b p.165 and BNF ). Propofol is particularly useful in day-case surgery, and for manipulation of fractures and dislocations, because recovery is rapid. The injection may be painful. Hypotension is c ommon and severe bradycardia may occur. Induction dose is 1.5 \200\2232.5mg/kg. Etomidate causes less hypotension than propofol or thiopental (and so may be useful in pati ents who are already hypotensive), and recovery is rapid. However, the injection is painful , and uncontrolled muscle movements and adrenocortical suppression may occur. Induction dos e is up to 0.3mg/kg. Ketamine ( b p.278) is used mainly in prehospital care, but may be use ful for rapid sequence intubation in hypotensive patients and in acute asthma. Induction do se is 1 \200\2232mg/kg IV. Thiopental (thiopentone) is a barbiturate drug. Thiopentone solution is unstable and has to be prepared from powder to form a 2.5 % solution (25mg/mL). Care is needed with injections because extravasation causes irritation, and arterial injection is particularly dangerous. Hypotension may occur, especially with overdosage. The induction dose in a \201 t adult is up to 4mg/kg (child: 2 \200\2237mg/kg). Muscle relaxants Suxamethonium is a short-acting depolarizing muscle relaxant, which is oft en used to allow intubation, especially in rapid sequence induction of anesthesia ( b p.312 ). In a dose of 1mg/kg it causes muscle fasciculation followed rapidly by \202 accid para lysis. Suxamethonium is contra-indicated in hyperkalaemia and also in burns, paraplegia or crush injuries, where dangerous hyperkalaemia may develop if suxamethonium is used 5 \200 \223120 days after injury. Suxamethonium causes i ICP and i intraocular pressure. Usual dur ation of action is 8 5min, but prolonged paralysis occurs in patients with abnormal pseudo- cholinesterase enzymes. Rocuronium is a muscle relaxant that may be used for intubation if suxamethonium is contrai ndicated. Atracurium and vecuronium are non-depolarizing muscle relaxants, which act for 8 20 \200 \22330min. They cause fewer adverse effects than older relaxants (eg pancuronium). Paralysi s from these drugs can be reversed with neostigmine, which is given with atropine or glycop yrronium to prevent bradycardia. 317 GENERAL anesthetic DRUGS Inhalational anesthetics These can be used for analgesia (especially Entonox ), inductio n of anesthesia (particularly in upper airway obstruction, when IV induction of anesthesia is hazardous), and for maintenance of anesthesia. Nitrous oxide (N 2 O) is widely used for analgesia as Entonox , a 50:50 mixture with O 2 ( b p.278). It is also used frequently i n GA in a concentration of 50 \200\22370 % in O 2 , in combination with other inhaled or IV anesthetics. N 2 O is contraindicated in certain circumstances (eg undrained pneumothorax) \200\224 see b p.278. Halothane, en \202 urane, iso \202 urane, and sevo \202 urane ar e inhalational anesthetic agents that are given using specially calibrated vaporizers in O 2 , or a mixture of N 2 O and O 2 . Sevo \202 urane is particularly useful for gas inducti on of anesthesia in upper airway obstruction. Halothane is also effective for gas induction , but now rarely used because of the risk of hepatotoxicity, especially after repeated use. Halothane sensitizes the heart to catecholamines, so adrenaline must not be used with halo thane. These inhalational anesthetic drugs can cause malignant hyperpyrexia ( b p.265) in s usceptible patients. This page intentionally left blank 319 Chapter 8 Major trauma Major trauma: treatment principles Investigations in major trauma Airway obstruction: basic measures Airway obstruction: surgical airway Tension pneumothorax Chest wall injury Trauma tic pneumothorax Haemothorax Chest drain insertion Pulmonary contusions and aspiration Pene trating chest injury Aortic injury Focused assessment with sonography for trauma 320 322 324 326 328 330 334 335 336 338 340 344 (FAST) scan 346 347 348 350 351 352 354 356 358 360 362 364 366 368 370 372 374 376 378 380 386 388 389 390 392 394 396 398 Diagnostic peritoneal lavage (DPL) Blunt abdominal trauma Penetrating abdominal trauma Rena l trauma Bladder, urethral, and testicular trauma Head injury: introduction Head injury: tr iage and monitoring Head injury: history Head injury: examination Head injury: imaging Mana gement of serious head injury Minor head injury Post-concussion symptoms Maxillofacial inju ries: introduction Middle third facial fractures Zygomatic, orbital and frontal sinus fract ures Mandibular injuries Penetrating neck trauma Spine and spinal cord injury Dermatomes Gu nshot injuries Blast injuries Burns: assessment Major burns: resuscitation Inhalation injur y Management of smaller burns Crush syndrome 320 CHAPTER 8 Major trauma Major trauma: treatment principles Patients who present with serious (or apparently serious ) injuries require immediate assessment and resuscitation. The \201 ner points of history taking may have to wait until later. However, suspect major trauma in: \200 High speed r oad collisions, vehicle ejection, rollover, prolonged extrication. \200 Death of another individual in the same collision. \200 Pedestrians thrown up or run over by a vehicle. \200 Falls of more than 2m. Management of speci \201 c injuries is outlined in subsequent pages. Although treatment should be tailored to the needs of each individual patient, many therapeutic interventions are common to all patients: Airway control Use basic maneuvers (suction, chin lift, oropharyngeal airway) to open the a irway and apply O 2 by face mask ( b p.324). Avoid tilting the head or moving the neck if t here is a chance of neck injury. If the airway remains obstructed despite these measures, g et ED and ICU and/or anesthesia help and consider advanced maneuvers ( b p.326). O 2 Provide high \202 ow O 2 to all. Patients who are apnoeic or hypoventilating require assistance by bag and mask ventilation prior to tracheal intubation and IPPV. Cervical spine control This is the \201 rst priority in any patient who presents with pos sible spine injury (eg neck pain, loss of consciousness). Provide immediate in-line manual cervical immobilization by placing one hand on each side of the patient \200\231s head and holding it steady (without traction) and in line with the remainder of the spine. Whilst ma intaining manual immobilization, ask an assistant to apply an appropriately sized hard cerv ical collar. Adhesive tape and sandbags may be applied, but may cause problems in certain p atients (eg patients who are vomiting or uncooperative patients who have consumed alcohol). IV \202 uids Insert 2 large cannulae into forearm or antecubital fossae veins. If initial attempts fail, consider a femoral venous line or an intra-osseous line. If these fail or a re inappropriate, consider a central line or a cut-down onto the long saphenous vein. Howev er, bear in mind the dif \201 culties and potential hazards of attempting central venous a ccess in hypovolaemic patients. Commence IV \202 uids for patients with hypovolaemic shoc k with 1L of 0.9 % saline (or Hartmann \200\231s solution) in adults (20mL/kg in children). Consider urgent blood transfusion if > 2L (in an adult) have been given ( b p.174) and loo k for sources of bleeding \200\224 chest, abdomen, and pelvis. Analgesia Adequate pain relief is often forgotten or deferred. Give morphine IV (diluted in saline to 1mg/mL) titrated in small increments according to response. Provide an antiemeti c (eg cyclizine 50mg IV) at the same time. Consider other forms of analgesia (eg regional n erve blocks, immobilization, and splintage of fractures). 321 MAJOR TRAUMA: TREATMENT PRINCIPLES Antibiotics Give prophylactic IV antibiotics for compound fractures and penetrating wounds of the head, chest or abdomen. Antibiotic choice follows local policy \200\224 a broad spe ctrum antibiotic (eg cefuroxime) is useful. Tetanus Ensure tetanus prophylaxis in all patients ( b p.410). Advanced trauma life support (ATLS ) The ATLS concept was introduced by the American College of Surgeons in an attem pt to improve the immediate treatment of patients with serious injury. The ATLS approach has enabled some standardization of trauma resuscitation. According to ATLS , treatment of all patients with major trauma passes through the same phases: \200 Primary survey. \200 Resuscitation phase. \200 Secondary survey. \200 De \201 nitive care phase. A ke y feature of ATLS is frequent re-evaluation of the patient \200\231s problems and the re sponse to treatment. Any deterioration necessitates a return to evaluate the \200\230ABC \200\231 (airway, breathing, and circulation). Primary survey On initial reception of a ser iously injured patient, life-threatening prob- lems should be identi \201 ed and addressed as rapidly as possible. An \200\230ABC \200\231 approach is adopted, with each of the fol lowing aspects being quickly evaluated and treated: A \200\224 airway maintenance with cer vical spine control. B \200\224 breathing and ventilation. C \200\224 circulation and hem orrhage control. D \200\224 disability (rapid assessment of neurological status). E \200 \224 exposure (the patient is completely undressed to allow full examination). With optimum staf \201 ng and direction, instead of considering each of these aspects sequ entially (from \200\230A \200\231 to \200\230E \200\231), aim to address them simultaneou sly. Resuscitation phase During this period, treatment continues for the problems identi \201 ed during the primary survey. Further practical procedures (eg insertion of oro/nasoga stric tube, chest drain and urinary catheter) are performed. Occasionally, immediate surger y (damage control surgery) is required for hemorrhage control before the secondary survey. Secondary survey This is a head to toe examination to identify other injuries. This should be accompanied by relevant imaging and other investigations. Monitor the patient closely \200\224 any deterioration requires a repeat ABC assessment. A high index of suspicion is e ssential to avoid missing occult injuries \200\224 particularly in the severely injured an d those with d conscious level. De \201 nitive care phase The early management of all inju ries is addressed, including fracture stabilization and emergency operative intervention. 322 CHAPTER 8 Major trauma Investigations in major trauma Select speci \201 c investigations according to the present ation, but bear in mind that all patients with major trauma require: group and save/X-match , BMG, X-rays, ABG. Consider measuring lactate levels. BMG This is mandatory for all patien ts with major trauma and particularly important on any patient with GCS<15/15. SpO 2 Attach a pulse oximeter on ED arrival, then monitor continuously. Blood tests Check U&E, FBC, and glucose in all patients. If there is any possibility of signi \201 cant hemorrhage, reque st a group and save, or cross-match. Request a baseline clotting screen in patients with ma jor hemorrhage or those at special risk (eg alcoholics or those on anticoagulants). Request fresh frozen plasma and platelets early for patients with major hemorrhage. X-rays Multipl y injured patients often require multiple X-rays. Obtain CXR and pelvic X-rays as a minimum . Cervical spine X-rays do not change the initial management in the resuscitation room and can be deferred to the secondary survey. Don lead aprons and gloves, and remain with the pa tient whilst X-rays are taken \200\224 in particular, ensure satisfactory immobilization o f the cervical spine throughout. Accompany the patient if he needs to be taken to the radio logy department for further imaging. Urinalysis Test the urine for blood if there is suspic ion of abdominal injury. Microscopic haematuria is a useful marker of intra-abdominal injur y. Arterial blood gas Provides useful information about the degree of hypoxia, hypoventilat ion and acidosis. In critically ill patients (especially those requiring ventilatory suppor t or those destined for neurosurgery/ICU) repeat as necessary and consider inserting an int ra-arterial line to continuously monitor BP. Electrocardiogram Monitor all patients; record an ECG if > 50 years or signi \201 cant chest trauma. Computed tomography scan CT is incr easingly used to evaluate head, neck and truncal injuries. An appropriately trained doctor should accompany the patient to the CT scanner and monitoring must continue. Local protocol s will dictate which patients have a total body \200\230pan scan \200\231 rather than sele ctive imaging. Patients with haemodynamic instability should not go to the CT scanner. USS (FAST) and DPL Focused assessment with sonography for trauma (FAST; b p.346) is a USS techn ique to identify free \202 uid in the peritoneal or pericardial cavities. It can be perfo rmed by a trained ED doctor, surgeon, or radiologist. Local policy and expertise will deter mine individual ED practice. DPL ( b p.347) is rarely used now in developed countries given the availability of FAST and CT. DPL still plays an important role if FAST and CT are not available. Other investigations Angiography is indicated in certain speci \201 c circumsta nces (major pelvic fracture, aortic injury). Occasionally, other tests requiring specialist expertise (eg echocardiography) may prove to be useful. 323 INVESTIGATIONS IN MAJOR TRAUMA Trauma scoring Trauma scoring is often used in research on the epidemiology and man- agemen t of trauma. A basic understanding of the accepted system of trauma scoring may be of bene \201 t to those treating injured patients. Injury Severity Score (ISS) The ISS is widely u sed to retrospectively score the anatomical injuries of an individual patient. The score is obtained by \201 rst scoring each individual injury using the Abbreviated Injury Scale ( AIS), which attributes a score between 1 and 6 to each individual injury, as follows: AIS 1 = minor injury AIS 2 = moderate injury AIS 3 = serious injury AIS 4 = severe injury AIS 5 = critical injury AIS 6 = inevitably fatal injury To calculate the ISS from an array of AIS scores for a patient, the 3 highest AIS scores in different body regions are squared then added together. ISS considers the body to comprise 6 regions: head/neck; face; chest; abdomen; extremities; external (skin). Possible ISS sco res range from 1 to 75. Any patient with an AIS = 6 is automatically given an ISS of 75. Se e www.aast.org/Library/TraumaTools/InjuryScoringScales.aspx For example, see Table 8.1 . Table 8.1 Injuries AIS (body region) Closed linear temporal skull fracture AIS = 2 (head/neck) Major aortic arch rupture at its root AIS = 5 (chest) Bilateral pulmonary contusions AIS = 4 (chest) Massive splenic rupture with hilar disruption AIS = 5 (abdomen) Multiple widespread super \201 cial abrasions AIS = 1 (external) ISS=(5) 2 + (5) 2 + (2) 2 = 54. The ISS is non-linear and some scores (eg 15) are impossibl e. One accepted de \201 nition of \200\230major trauma \200\231 is an ISS > 15. The Revised Trauma Score The Revised Trauma Score (RTS) is used to assess the physiological disturbance of a trauma patient. The score is calculated from the respira- tory rate, syst olic BP and GCS. Each of these parameters are assigned a code (value) to which a weighting factor is applied. The 3 resultant scores are then added together to give the RTS. The RTS ranges from 0 (worst possible) to 7.84 (best). TRISS methodology Combining the ISS with the RTS and adding a weighting factor according to the age of the patient, it is possible to c alculate a \200\230Probability of Survival \200\231 (Ps) for each patient, based upon the national norm. Patients who survive with Ps<0.5 are regarded as \200\230unexpected survivo rs \200\231; patients who die with Ps > 0.5 as \200\230unexpected deaths \200\231. By anal yzing the results of treating a large number of patients, TRISS methodology may be used to compare \200\230performances \200\231 (eg of one hospital against the national norm). 324 CHAPTER 8 Major trauma Airway obstruction: basic measures Severely injured patients die rapidly unless oxygenated blood reaches the brain and other vital organs. Clear, maintain, and protect the airway, en sure that ventilation is adequate and give O 2 in as high a concentra- tion as possible. Th e most urgent priority is to clear an obstructed airway, but avoid causing or exacerbating any neck injury: instruct someone to hold the head and neck in a neutral position until the neck is satisfactorily immobilized. Ensure you always wear personal protective equipment. When treating any seriously injured patient, always ensure that O 2 , suction and airway eq uipment are readily available. Get senior ED ICU/anesthetic help early if a patient with a serious airway problem arrives or is expected. Causes of airway obstruction \200 Coma from any cause can result in airway obstruction an d loss of protective airway re \202 exes. Blood or vomit may block the airway. \200 The airway may be disrupted by trauma of the fa ce or larynx, or may be occluded by a haematoma or by oedema following burns. Assessment of airway obstruction Talk to the patient and see if he responds. A lucid reply shows that the airway is patent, that he is breathing and that some blood is reaching the b rain, at least for the moment. Ensure that the neck does not move until it has been checked and cleared of injury ( b p.320). Look and listen to check how the patient is breathing. C omplete airway obstruction in someone who is still trying to breathe results in paradoxical movements of the chest and abdomen, but no breath sounds. Gurgling, snoring and stridor ar e signs of partial obstruction. Management of airway obstruction \200 Look in the mouth and pharynx for FBs, blood, and v omit. The tip of a laryngoscope may be useful as an illuminated tongue depressor. Remove any FB with Magill \200\231s forceps and suck out any liquid with a large rigid suct ion catheter. See if the patient responds and has a gag re \202 ex, but beware of precipit ating coughing or vomiting. If vomiting occurs, tilt the trolley head down and suck out any vomit. \200 Lift the chin and use the jaw thrust maneuver (see opposite) to open the airway, but do not \202 ex or extend the neck. After any airway intervention, look, listen, and feel to reassess airway patency and ef \201 cacy of breathing. If the gag re \202 ex is absent or poor, insert an oropharyngeal airway (see opposite). Th is helps to hold the tongue forwards, but can cause vomiting or coughing if there is a gag re \202 ex. If the gag re \202 ex is present or the patient \200\231s jaws are clenched, consider a nasopharyngeal airway . Although a nasopharyngeal airway is useful in some situa tions, avoid its use if there is evidence of severe facial or head injury. If the airway is now patent and the patient is breathing, give high concentration O 2 (15L/min via a non-rebreathing reservoir mask). If the airway is patent, but breathing inadequate, ventilate the patient with O 2 bag and m ask device and prepare for tracheal intubation. If possible, one person should hold the mas k on the face with both hands to ensure a good seal, whilst a second person squeezes the ve ntilation bag. 325 AIRWAY OBSTRUCTION: BASIC MEASURES Insertion of oropharyngeal airway \200 Select the appropriate size of airway. \200 Hold an airway against the patient \200\231s face. A correctly sized airway reaches from the co rner of the mouth to the external auditory canal. A large adult usually needs a size 4 airw ay, most men require size 3, some women need a size 2. An incorrectly sized airway may make the obstruction worse, rather than better. Open the patient \200\231s mouth and use a rigid suction catheter with high power suction t o suck out any \202 uid or blood from the oropharynx. \200 Insert the oropharyngeal air way \200\230upside down \200\231 for 4 \200\2235cm (half way), then rotate it 180 and insert it until the \202 ange is at the teeth. In children, use a laryngoscope as a tongue depressor and insert the airway the \200\230correct way up \200\231 to avoid trauma to the palate. \200 Re-check the airway and breathing and give high \202 ow O 2 . \200 Ventilate the patient if brea thing is inadequate. Insertion of nasopharyngeal airway \200 Select an appropriate airway, usually a 7.0mm for adult males and a 6.0mm for adult females. A safety pin through the \202 ange end will p revent displacement into the nose or nasopharynx. Lubricate the airway with water or a water-soluble lubricant. \200 Insert the tip of the airway into one nostril and direct the airway posteriorly, aiming the tip at the tragus of the ear. The airway should slide easily into the nose until the \202 ange abuts the nostril and th e tip is just visible in the pharynx. Never force a nasopharyngeal airway into the nostril \200\224 any bleeding produced will markedly aggravate the airway problem. Re-check the airway and breathing and give high \202 ow O 2 . Jaw thrust maneuver The aim of this is to open the upper airway with minimum movement of the cervical spine. Place the fore \201 ngers of both hands immediately behind the angles of the mandible and push the mandible anteriorly. This will lift the tongue anteriorly and thus away from the posterior pharyngeal wall. Tracheal intubation in trauma An injured patient who has no gag re \202 ex needs tracheal intubation to maintain the airway and protect it against blood and vomit. Intubation may al so be needed because of: apnoea (after initial ventilation with a bag-valve-mask), respirat ory inadequacy, to prevent potential obstruction from facial burns or to allow manipulation of ventilation in patients with i ICP). Intubation in such circumstances requires emergenc y anesthesia: suitable expertise, appropriate equipment and assistance are essential ( b p. 312). An assistant must hold the head to prevent movement of the neck during intubation, wh ile another assistant provides cricoid pressure. Con \201 rm correct tracheal tube placeme nt by: \200 Seeing the tube pass through the cords. \200 Observing symmetrical chest mo vement. \200 Listening over both axillae for symmetrical breath sounds. \200 Con \201 rming placement with end-tidal carbon dioxide (CO 2 ) monitoring. If airway obstruction is complete, the obstruction cannot be relieved and intubation is impossible, an urgent surgic al airway is needed ( b p.326). 326 CHAPTER 8 Major trauma Airway obstruction: surgical airway Surgical cricothyroidotomy or jet insuf \202 ation of the airway via a needle cricothyroidotomy is needed if the airway is obstructed by trauma, oedema or infection, and the trachea cannot be intubated. Emergency tracheostomy is not ind icated in this situation because it is too time- consuming to perform and the necessary exp ertise may not be available.