ACUTE MEDICAL EMERGENCIES - PART 10 pot

The femoral vein 1. Place the patient in a supine position. 2. Under sterile conditions, palpate the femoral artery (midinguinal point). The femoral vein lies directly medial to the femoral artery (remember lateral to medial structures are femoral nerve, artery, vein, space). 3. Infiltrate the puncture site with local anaesthetic. 4. While palpating the femoral artery insert the needle over the femoral vein parallel to the sagittal plane at an angle of 45° to the skin, aspirating at all times. A free flow of blood entering the syringe will confirm entry into the vein. 5. Advance the guide wire through the needle as described below. Complications ● Venous thrombosis ● Injury to artery or nerve ● Infection ● Arteriovenous fistula ● Air embolism In addition, attempts at internal jugular or subclavian vein access may cause pneumo- thorax, haemothorax, and chylothorax. Seldinger technique Equipment Skin cleaning swabs Lignocaine 1% for local anaesthetic with 2 ml syringe and 23 gauge needle Syringe and heparinised 0.9% saline Seldinger cannulation set: syringe needles Seldinger guide wire cannula Suture material Prepared infusion set Tape Procedure Although initially described for use with arterial cannulation, this technique is very suit- able for central venous cannulation and is associated with an increased success rate. It relies on the insertion of a guide wire into the vein over which a suitable catheter is passed. As a relatively small needle is used to introduce the wire, damage to adjacent structures is reduced. Having decided which approach to use (see earlier), the skin must be prepared and towelled. Full aseptic precautions are necessary as a “no-touch” technique is impossible. 1. Check and prepare your equipment; in particular, identify the floppy end of the guide wire and ensure free passage of the guide wire through the needle. 2. Attach the needle to a syringe and puncture the vein. 3. After aspirating blood, remove the syringe taking care to avoid the entry of air (usu- ally by placing a thumb over the end of the needle). PRACTICAL PROCEDURES: CIRCULATION 413 28-AcuteMed-28-cpp 28/9/2000 5:09 pm Page 413 4. Insert the floppy end of the guide wire into the needle and advance 4–5 cm into the vein. 5. Remove the needle over the wire, taking care not to remove the wire with the needle. 6. Load the catheter on to the wire, ensuring that the proximal end of the wire pro- trudes from the catheter. Holding the proximal end of the wire, insert the catheter and wire together into the vein. It is important never to let go of the wire! 7. Remove the wire holding the catheter in position. 8. Reattach the syringe and aspirate blood to confirm placement of the catheter in the vein. If it is difficult to insert the wire, the needle and wire must be removed together. Failure to do this may damage the tip of the wire as it is withdrawn past the needle point. After three minutes gentle pressure to reduce bleeding, the needle can be reintroduced. Occasionally it may be necessary to make a small incision in the skin to facilitate the passage of the catheter. ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 414 28-AcuteMed-28-cpp 28/9/2000 5:09 pm Page 414 CHAPTER 29 Practical procedures: medical PROCEDURES ● Joint aspiration ● Balloon tamponade of oesophageal varices ● Lumbar puncture ● Blood cultures ● Insertion of pulmonary arterial flotation (Swan–Ganz) catheter ● Pulmonary capillary wedge pressure JOINT ASPIRATION Diagnostic indications ● Suspected septic arthritis ● Crystal induced synovitis ● Haemarthrosis Therapeutic indications ● Tense effusions ● Septic effusions recurrent aspiration lavage (rare) ● Haemarthrosis ● Steroid injection Contraindications ● Overlying skin infection/cellulitis Equipment Antiseptic solution, e.g. ethanol, povidone iodine Swabs 415 Reading: 15 minutes 29-AcuteMed-29-cpp 28/9/2000 5:12 pm Page 415 Sterile gloves Syringes: 5, 10, 20 ml Needles: large joint (21 gauge) green Needles: small joint (23 gauge) blue Procedure 1. Explain to the patient what you are going to do. 2. Identify the bony margins of the joint space. 3. Ensure you have all the appropriate materials required. 4. Using a sterile technique prepare the skin. 5. Inject a small amount of local anaesthetic (1% lignocaine) into the skin over the joint to be aspirated. 6. Gently insert the needle into the joint space. Normally a green needle (21 gauge) will suffice for most joints, but for finger and toe joints a blue (23 gauge) needle is advised. 7. Aspirate fluid and send for microbiological assessment, crystals, cytology, protein, lactate dehydrogenase (LDH), and glucose estimation. Specific procedures Knee joint aspiration 1. Ensure the patient is as comfortable as possible. 2. Slightly flex the knee to ensure relaxation of the quadriceps muscles. 3. Palpate the posterior edge of the patella medially or laterally. Using the earlier general technique insert the needle horizontally or slightly downwards into the joint between the patella and femur (often a slight resistance is felt when the needle penetrates the synovial membrane). Shoulder joint aspiration This joint is easier to access through an anterior approach although a lateral and posterior approach is also possible. The anterior approach will be described. 1. Ensure that the patient is seated with their arm relaxed against the side of their chest. 2. Palpate the space between the head of the humerus and the glenoid cap, about 1 cm below the cricoid process. 3. Using the earlier general procedure insert the needle into the space with a slight medial angle (it should enter the joint easily and to almost the length of the green needle). Complications ● Reaction to topical skin preparation. ● Inappropriate puncture of blood vessels or nerves. ● Introduction of infection into joint space. BALLOON TAMPONADE OF OESOPHAGEAL VARICES Equipment Sengstaken–Blakemore tube Two spigots ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 416 29-AcuteMed-29-cpp 28/9/2000 5:12 pm Page 416 60 ml bladder syringe Saline/contrast media Tongue depressors Tape Anaeroid pressure gauge Suction Drainage bags Procedure Variceal bleeding can be controlled by balloon compression either at the cardia or within the oesophageal lumen. A large number of devices are available for this purpose, the commonest is a Sengstaken–Blakemore tube that has been modified to allow aspiration of gastric and oesophageal contents as well as inflation of gastric and oesophageal balloons. Insertion of the tube usually occurs in conscious patients and, therefore, the nasal route is advocated. Unfortunately this can make insertion difficult but is subsequently better tolerated by the patient. If the airway is in jeopardy, ensure that it is cleared and secured before attempting to insert the tamponade tube. If the patient has an endotra- cheal tube in situ, the oral route is advocated. Although you may be faced with torrential bleeding from oesophageal varices, ensure that you have all the equipment available before you attempt insertion of this tube and, more importantly, that the associated oesophageal and gastric balloons will inflate and remain inflated. It is important to realise that tamponade tubes are difficult to introduce and they require meticulous supervision whilst inflated. 1. Lubricate the tube with water soluble jelly. 2. Providing that there are no contraindications, insert the tube into the right nostril using a technique similar to that described for nasopharyngeal airway insertion in Chapter 30. Ensure you direct the tube backwards (not superior or inferior). 3. Advance the tube gently. It will follow the contour of the oropharynx into the oesophagus. 4. Advance the tube until you reach the 50 cm mark (note that the tube has 5 cm grad- uations). Advancing the tube to at least 50 cm will, in most patients, ensure that it is in the stomach. Aspiration of blood does not, however, verify this. 5. Inflate the gastric balloon with 200 ml of air or alternatively 200 ml of water soluble contrast material. Gentle traction of the nasal end of the tube will ensure that the inflated gastric balloon is adjacent to the cardia and gastro-oesophageal junction. 6. Tape the balloon to the side of the patient’s face. Often inflation of the gastric bal- loon, with gentle traction, is all that is required to stem variceal bleeding as the feed- ing vessel to the varices, the left gastric vein, is tamponaded by this manoeuvre. If this fails to control the bleeding then inflate the oesophageal balloon with air to 4·5–5·4 kPa (30–40 mm Hg) using a pressure gauge. If a specific pressure gauge is not available then it is possible to adapt a sphygmomanometer for this purpose. 7. Ensure that both gastric and oesophageal aspiration ports are draining freely. Both the gastric and oesophageal balloons seal automatically once inflated by one-way valves. Continuous oesophageal suction reduces the risk of aspiration. 8. Deflate the balloon after 24 hours. This will reduce the risk of oesophageal mucosal ulceration and perforation. It is important to realise that balloon tamponade is only a temporising procedure and once the bleeding has stopped the patient should undergo oesophageal sclerotherapy. PRACTICAL PROCEDURES: MEDICAL 417 29-AcuteMed-29-cpp 28/9/2000 5:12 pm Page 417 Complications ● Aspiration, especially without continuous aspiration of the oesophageal port ● Hypoxaemia, if the balloon is inadvertently inserted into the trachea ● Tracheal rupture, as above ● Oesophageal rupture.The procedure is performed blindly and with the presence of a hiatus hernia or an oesophageal stricture it is possible for the Sengstaken–Blakemore tube to coil in the oesophagus. Inflation produces catastrophic results ● Mucosal ulceration in the oesophagus and stomach ● Failure to stop variceal haemorrhage LUMBAR PUNCTURE Indications ● Suspected meningitis ● Subarachnoid haemorrhage ● Encephalitis ● Benign intracranial hypertension Contraindications ● Raised intracranial pressure ● Spinal cord compression ● Local sepsis ● Bleeding disorders Equipment Antiseptic solution Gauze swabs Sterile drapes and gloves 1% lignocaine (max 5 ml) 5ml syringe Needles: 25 gauge (orange) Needles: 21 gauge (green) Lumbar puncture needles Manometer Collection bottles Tape Procedure 1. Explain to the patient what you are going to do. 2. Place the patient in the left lateral position, ensuring that their back, in particular the lumbar spine, is parallel to the edge of the bed. The hips and knees should be flexed to greater than 90º and the knees separated by one pillow. Ensure that the head is supported on one pillow and that the patient’s cervical and thoracic spine are gently flexed. 3. Check that you have all the necessary equipment. 4. Identify the fourth lumbar vertebra, i.e. a line drawn between the top of the iliac crests. 5. Thoroughly cleanse the skin using an aseptic technique. ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 418 29-AcuteMed-29-cpp 28/9/2000 5:12 pm Page 418 6. Identify the interspace between the second and third or third and fourth lumbar vertebrae (hence the spinal cord will not be damaged). In the midline, inject a small amount of 1% lignocaine to raise a skin bleb. 7. Through the skin bleb, advance a green needle and ensuring that the blood vessel has not been punctured. Inject 1 ml local anaesthetic into the interspinous ligament in the respective interspace. Too much local anaesthetic will cause damage to these tissues and produce profound discomfort. 8. Using a sterile spinal needle advance through the anaesthetised tissues, directing the needle slightly cephalad and maintaining a midline position. 9. As you enter the subarachnoid space, a sudden change in resistance on advancing the needle is felt. Then gently remove the inner trochar and watch for a drop of cerebrospinal fluid appearing at the end of the needle. If this does not occur, replace the central trochar and advance the needle again, until a change in resistance is felt. Repeat the procedure until cerebrospinal fluid is seen. 10. Attach the manometer and measure the pressure of the cerebrospinal fluid. 11. Place five drops of cerebrospinal fluid sequentially in three tubes for red cell count, then five drops in a further two for microscopy culture and sensitivity. Similar samples should be taken for protein estimation, spectroscopy, virology, and glucose (the latter should be placed in a fluoride tube). 12. Note the colour of the cerebrospinal fluid, i.e. whether it is clear, opalescent or yellow (xanthochromia). 13. Remove the needle and ensure that the patient stays supine for four hours. Occasionally, postlumbar puncture headache may result which necessitates simple analgesia with paracetamol. Complications ● Failure to obtain cerebrospinal fluid may be due to incorrect anatomical positioning, “a dry tap”, degenerative or inflammatory changes in the lumbar spine ● Nerve root pain when inserting the needle – usually transient ● Introduction of sepsis ● Bleeding ● Headache ● Coning BLOOD CULTURES Indications ● Pyrexia of unknown origin ● Septicaemia ● Suspected infective endocarditis Procedure 1. Thoroughly cleanse the skin, ideally with an alcohol based solution. 2. Whilst this is evaporating to dryness wash your hands thoroughly; under aseptic conditions don surgical gloves. 3. At the previously prepared site perform a venepuncture and aspirate 40 ml of blood. 4. Thoroughly cleanse the top of the blood culture bottle. 5. Insert 10 ml of blood into each blood culture bottle. PRACTICAL PROCEDURES: MEDICAL 419 29-AcuteMed-29-cpp 28/9/2000 5:12 pm Page 419 It is important to realise that if you suspect infective endocarditis, then two sets of blood cultures from three different sites should be taken. Complications ● Bleeding ● Sepsis at venepuncture site INSERTION OF PULMONARY ARTERIAL FLOTATION (SWAN–GANZ) CATHETER Indications ● Measurement of pulmonary capillary wedge pressure (PCWP) ● Pulmonary artery end diastolic pressure (PAEDP) ● Cardiac output Equipment See central venous cannulation in Chapter 28. The catheter This is a balloon tipped device with a single distal hole. It can be inserted at the bedside without X-ray control or under fluoroscopy. The balloon serves two purposes. Firstly as soon as the catheter is inserted into a cen- tral vein, inflation of the balloon with air will ensure that it acts as a “sail” navigating the catheter through the tricuspid and pulmonary valves. Changes in the pressure tracing, as described later, will enable these structures to be identified. Furthermore, once the catheter is inserted into a small pulmonary artery, the balloon may then be inflated, occluding the artery proximally.This will leave the catheter tip exposed to the pulmonary capillary wedge pressure. Catheter insertion 1. Using the technique described for central venous access in Chapter 28, advance the catheter into a large vein. If an insertion sheath is used, ensure it is one size larger than the catheter, to ensure passage of the deflated balloon through the insertion sheath. 2. Connect to transducer. 3. Inflate the balloon. 4. Slowly advance the catheter tip, guided by the blood flow. 5. Advance the catheter through into the pulmonary artery bed, trying to find a posi- tion which gives a good pulmonary artery tracing with the balloon deflated and a good wedge pressure with the balloon inflated. 6. X-ray the chest. Alternatively, the catheter can be inserted under fluoroscopic control. It is, however, still important to ensure that a good pulmonary artery tracing is obtained with the balloon deflated, and a good wedge pressure is obtained with the balloon inflated. ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 420 29-AcuteMed-29-cpp 28/9/2000 5:12 pm Page 420 Measurement Specific details of pulmonary capillary wedge pressure measurement will vary according to the equipment available. There are, however, certain common features. 1. Most equipment is designed for continuous monitoring; as such it is precalibrated. Therefore the only major adjustment is to zero the transducer to atmospheric pres- sure before recording.To do this ensure that the catheter is connected via a three-way tap to the manometer line; the other portholes of the three-way tap should be connected to a flushing system and to the air. It is also mandatory to ensure that, in setting up the equipment, you bleed all air bubbles from the system. 2. Move the three-way tap to ensure that blood cannot flow back from the catheter to the transducer but that the final port of the three-way tap is open to the air. 3. Adjust the tracing on the monitor to zero. 4. Close the transducer sidearm and open the transducer to the catheter. Ideally allow approximately 30 min for the transducer to “warm up”. Measurements are made with the patient flat and the transducer at the angle of Louis. You will note that during measurements the pressure swings related to respiration will impart a biphasic nature to the pulmonary wedge pressure. It is, therefore, important that the mean wedge pressure is used. It is always important to check: ● the transducer level ● that the system is set at zero ● that wedging does not occur. Problems ● Failure to wedge – reposition the catheter. ● Flat/damp trace – unblock catheter. Ensure that there is no air in the system and that the transducer is not open to both the patient and air. Flush the system – usually a hand flush of 1 ml of saline is required, but ensure that no air is introduced. ● Overwedging – occasionally the catheter is lodged in a pulmonary artery; unfortu- nately, the diameter of this vessel is less than that of the balloon and does not allow accurate pressure recording.This usually manifests by a fluctuating, steadily increas- ing pressure trace. Ideally deflate the balloon and reposition the catheter. PULMONARY CAPILLARY WEDGE PRESSURE This can be recorded as described earlier, along with pressures in the pulmonary artery, right ventricle, and right atrium (Table 29.1). Table 29.1 Normal pressure ranges The pulmonary capillary wedge pressure is an indirect reflection of left arterial pressure (LAP). This in turn is similar to left ventricular end diastolic pressure (LVEDP). Site Pressure (mm Hg) Right atrium (mean) –1–60 Right ventricle 0–25 Pulmonary artery (mean) 10–20 Pulmonary capillary wedge pressure (mean) 8–15 PRACTICAL PROCEDURES: MEDICAL 421 29-AcuteMed-29-cpp 28/9/2000 5:12 pm Page 421 In certain acute medical conditions, the pulmonary capillary wedge pressure does not accurately reflect left ventricular end diastolic pressure.With pulmonary venous obstruc- tion, for example, pulmonary emboli or raised intrathoracic pressure (for instance, inter- mittent positive pressure ventilation) the pulmonary capillary wedge pressure is less than the left ventricular end diastolic pressure – thus pulmonary capillary wedge pressure is a particularly useful measurement in patients with poor left ventricular function and it may be used to optimise fluid therapy. CARDIAC OUTPUT Cardiac output may be assessed using the Fick equation which relates cardiac output (CO) to oxygen uptake ( VO 2 ). In this manner cardiac output equals oxygen uptake divided by the difference in arteriovenous oxygen content. Cardiac output = Therefore CO (l/min) = To obtain these values a true mixed venous sample of blood must be taken from the tip of the pulmonary artery. This will allow the difference in the arteriovenous oxygen con- tent to be assessed. Complications ● As with central venous access ● Pulmonary parenchymal damage VO 2 (ml/min) CaO 2 – CvO 2 (ml/l) Oxygen uptake Arteriovenous oxygen content difference ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 422 29-AcuteMed-29-cpp 28/9/2000 5:12 pm Page 422 [...]... 1 hour In severe or life threatening acute asthma not responding to nebulised β2 agonist, IV therapy is indicated Consider need for anaesthetic help Infusions of salbutamol are used following IV bolus Reduces mortality post myocardial infarction Indicated when potential benefits outweigh risks Risks mainly relate to haemorrhage (see Chapter 10) 427 ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH Drug... bifurcation of arteries These will depend on the extent of the occlusion of the circulation and the degree of co-lateral circulation 437 ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH ● Medical features include pain, pallor, pulselessness, parathesia, paralysis and perishing cold ● In contrast a closed compartment syndrome is caused by a swollen or a contused muscle or bleeding into the muscle from inside... brain stem function alteration 153 specific conditions asthma 47, 56, 88–93, 425, 427 pleural effusion 101 , 102 –6 pneumonia 96 101 , 102 , 220, 298, 426 pneumothorax 93–6 see also pneumothorax pulmonary embolism 106 –11 see also pulmonary embolism summary 111 time out answers 432–4 questions 85, 87, 93, 96, 99, 100 breathing, primary assessment and resuscitation 17–18, 39–49, 84, 122 airway 16–17, 30–1, 46–7,... should have a rapid primary assessment with reference to a serum glucose estimation 435 ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH CHAPTER 14: THE PATIENT WITH A HEADACHE 14.1, a These can be classified as intracranial e.g meningitis, encephalitis and subarachnoid haemorrhage or extracranial – acute sinusitis, acute viral illness, malaria or typhoid b Weakness usually affects the proximal and distal... considered Hydrocortisone Anaphylaxis and angiooedema 100 –300 mg IV Of secondary benefit as onset of action delayed for several hours Use in more severely affected patients Acute adrenocortical insufficiency 100 mg IV 6–8 hourly Ipratropium bromide Acute asthma 500 µg nebulised 4 hourly Indicated in life threatening asthma in conjunction with a β2 agonist In severe acute asthma use as a second line treatment Beneficial... (i) Acute asthma; pulmonary embolus; cardiac e.g dysrhythmia; neurological e.g status epilepticus; neuromuscular e.g myasthenia gravis (ii) The commonest cause is ischaemic heart disease Others include valvular pathology, acute hypertension, cardiomyopathy (iii) Any chronic neurological disorder can have the final common pathway of brain failure Dementia is another cause These are not acute medical emergencies, ... indications 215 secondary assessment 216–23 examination 219–21 history 216–19 investigations 221–2 pain chart 217 potential pitfalls 222–3 summary 234 specific conditions acute gastroenteritis 218, 220, 225–7 acute mesenteric infarction 214, 220, 232–3 acute pancreatitis 214, 216, 218, 221, 227–9 acute upper gastrointestinal bleeding 230–1 see also gastrointestinal haemorrhage Crohn’s disease 234 myocardial... and reactions along with evaluation of the conscious level (either the AVPU system or the Glasgow Coma Score is appropriate) CHAPTER 3: A STRUCTURED APPROACH TO MEDICAL EMERGENCIES 3.1 The primary assessment would comprise: 429 ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH ● Airway – assess patency As the patient is talking no intervention at this stage is required except for high flow oxygen (FiO2... hypotension 182 status epilepticus 180–1 stroke 171–5 time out questions and answers 183, 437 transient collapse 175–80 vasovagal syncope 177, 178, 181 colloid challenge 125 coma 10, 20, 149, 150, 153 causes of 154 metabolic 151 Glasgow Coma Scale (GCS) 10, 19, 150–1 hyperosmolar non-ketotic coma (HONK) 290 combitube insertion 398–9 community acquired pneumonia 97–9 assessment 98 management 98–9 compartment... 234 crystalloid 18, 125, 127, 129 Cullen’s sign 220, 228 cutaneous lymphoma 259 cyanosis 8 D-dimer assays 109 , 240, 286, 381 deaths, avoidable 5 decerebrate posturing 10 decorticate posturing 10 deep vein thrombosis (DVT) 127, 238–9, 241 management 240 time out questions and answers 239, 439 defibrillation hypothermic patients 306 paddles 349 definitive care 25, 27 dehydration 18, 219, 223, 386 gastroenteritis . oxygen content difference ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 422 29-AcuteMed-29-cpp 28/9/2000 5:12 pm Page 422 PART VIII APPENDIX 30-AcuteMed-Appx-cpp 28/9/2000 5:14 pm Page 423 This. to approximately 10 mg ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 426 30-AcuteMed-Appx-cpp 28/9/2000 5:14 pm Page 426 Drug Indications Dose and route Notes Glyceryl Pulmonary oedema secondary 1 10 mg/hour. the passage of the catheter. ACUTE MEDICAL EMERGENCIES: THE PRACTICAL APPROACH 414 28-AcuteMed-28-cpp 28/9/2000 5:09 pm Page 414 CHAPTER 29 Practical procedures: medical PROCEDURES ● Joint aspiration