Radiology for Anaesthesia and Intensive Care - Part 10 doc

Applications of ultrasound for patients on intensive care units Ultrasound imaging has a huge variety of applications for patients on intensive care units. These include both diagnostic and therapeutic applications, some of the more common applications are listed below. Ultrasound is readily portable and can often be performed at short notice. The size of machines, the quality and resolution of images has improved over the last decade. It is a versatile imaging modality with many applications on intensive care units. Thoracic Diagnosic applications  Pleural effusions (see Fig. 7.1).  Empyema.  Pleural biopsy. Therapeutic applications  Fluid aspiration.  Chest drain insertion (see Fig. 7.2). Abdomen Diagnosic applications  Biliary disease – gallstones (see Fig. 7.3), bile duct obstruction (see Fig. 7.4), cholecystitis. Ultrasound and intensive care 7 304 Fig. 7.1 Pleural effusion. The collapsed lung can be seen within the pleural fluid. Fluid is readily identified using ultrasound whether in the pleural space or within the abdomen. Chap-07.qxd 09/Oct/02 11:08 AM Page 304  Pancreatic disease and its complications, e.g. pancreatitis and pseudocysts (see Fig. 7.5).  Renal disease – stones, hydronephrosis (see Fig. 7.6), parenchymal thickness, etc.  Bowel pathology – appendicitis (see Figs 7.7 and 7.8).  Abdominal trauma – solid organ injury with free fluid (Fig. 7.9), ascites (Fig. 7.10). Applications of ultrasound for patients on intensive care units 7 305 Fig. 7.2 Pleural effusion drainage – pigtail catheter. The insertion of pigtail catheters on intensive care units is performed most safely using ultrasound guidance. Fig. 7.3 Gallstones. Multiple echogenic stones are present which cast an acoustic shadow posteriorly. The demonstration of gallstones on intensive care units can be important in cases of obstructive jaundice, cholecystitis and pancreatitis. Chap-07.qxd 09/Oct/02 11:08 AM Page 305 Ultrasound and intensive care 7 306 Fig. 7.4 Dilated bile duct. The diameter of the duct can be accurately measured with ultrasound and in cases of obstruction, the cause may be identified such as this gallstone. Duct size increases with age or following cholecystectomy. Fig. 7.5 Pancreatic pseudocyst. This is one of the complications of pancreatitis which is readily diagnosed on ultrasound. If the collections become infected, then ultrasound-guided drainage is appropriate. Sterile collections do not usually require drainage. Chap-07.qxd 09/Oct/02 11:08 AM Page 306 Applications of ultrasound for patients on intensive care units 7 307 Fig. 7.6 Hydronephrosis. The pelvicalyceal system is dilated. Proximal causes of obstruction such as proximal calculi can be diagnosed on ultrasound; the ureters are, however, poorly seen except the distal few centimetres at the vesicoureteric junction. Fig. 7.7 Appendicitis. Ultrasound has poor sensitivity but high specificity in the diagnosis of appendicitis. Features include a ‘lith’, (arrow) a blind ending, non-compressible loop of bowel 6 mm or greater in diameter and surrounding fluid. Chap-07.qxd 09/Oct/02 11:08 AM Page 307 Ultrasound and intensive care 7 308 Fig. 7.8 Appendicitis. Images in transverse section demonstrating failure of compression of the appendix. Fig. 7.9 Free fluid from splenic trauma. Ultrasound is extremely sensitive in the identification of free fluid. In the setting of trauma, the absence of free fluid is very useful in excluding intra-peritoneal haemorrhage. It has largely replaced diagnostic peritoneal lavage (DPL). Chap-07.qxd 09/Oct/02 11:08 AM Page 308 Applications of ultrasound for patients on intensive care units 7 309 Fig. 7.10 Abdominal ascites. The anechoic fluid is readily visualised in this patient with chronic liver disease. Fig. 7.11 Abdominal abscess in a patient with diverticular disease. Therapeutic applications  Gall bladder drainage.  Pseudocyst/ascitic drainage.  Abscess drainage (see Figs 7.11 and 7.12). Chap-07.qxd 09/Oct/02 11:08 AM Page 309 Ultrasound and intensive care 7 310 Fig. 7.12 Drainage of abdominal abscess. Ultrasound is the imaging modality of choice for the drainage of suitable abdominal abscesses. Real-time visualisation is possible for the insertion of pigtail drains – which are well seen on ultrasound. This is a portable technique which can be used on intensive care units. Fig. 7.13 DVT. A combination of grey scale ultrasound and Doppler ultrasound is used in the diagnosis of deep vein thrombosis. A normal vein can be compressed, it demonstrates phasic flow in time with respiration and squeezing on the limb augments blood flow. Deep vein thrombosis interrupts flow and prevents complete compression of the vein. The clot is frequently directly visualised. The technique is eminently suitable for patients on intensive care units, many of whom are at high risk of DVT. Chap-07.qxd 09/Oct/02 11:08 AM Page 310 Vascular: arterial and venous Diagnosic applications  Ischaemic limbs.  Deep vein thrombosis (upper and lower limbs) (see Fig. 7.13). Therapeutic applications  Guided insertion of internal jugular lines. Musculoskeletal Diagnosic applications  Septic arthropathy. Therapeutic applications  Joint aspiration. Ultrasound can be used to guide an extremely wide range of procedures including guided central line insertion, pleural aspiration, marking sites for safe insertion of chest drains, solid organ or tumour biopsy and various abdominal work. There are several advantages of ultrasound over other forms of imaging, which make it extremely useful for sick or ventilated patients and especially those with numerous support tubes and patients on intensive care units who cannot be moved (Table 7.1). Applications of ultrasound for patients on intensive care units 7 311 Table 7.1 Advantages and disadvantages of ultrasound Advantages 1. Portable – patients need not be moved 2. No ionising radiation 3. Imaging is in real time so allowance can be made for patient movement or breathing during interventional procedures 4. Imaging is not restricted to fixed planes, e.g. sagital, coronal Disadvantages 1. Small field of view 2. Image quality is restricted in large obese patients 3. Bowel gas impairs image quality 4. Ultrasound is operator dependent and requires specialist training Chap-07.qxd 09/Oct/02 11:08 AM Page 311 Ultrasound imaging: case illustrations Question 1 47-year-old Female. Requires central line insertion. Neck ultrasound. Transverse plane.  Name the structures in the image (Figs 7.14 and 7.15).  Briefly outline how ultrasound can be used to guide central line insertion. Ultrasound and intensive care 7 312 Fig. 7.14 Quiz case. Chap-07.qxd 09/Oct/02 11:08 AM Page 312 Ultrasound imaging: case illustrations 7 313 Answer Ultrasound guidance central line insertion The internal jugular vein (No. 1) and the common carotid artery (No. 2) are adjacent structures in the neck. US image guidance is invaluable when inserting jugular venous central lines. A high frequency linear or curvilinear probe should be selected. If no previous lines have been inserted, the right side is generally chosen as this is the larger vein with a more direct course to the SVC. Scanning the neck will identify the course of the jugular, confirm patency, the relationship to the carotid and assess whether there are any intervening structures such as lymph nodes. The jugular is thin walled, its calibre varies with respiration and it can be occluded with mild compression. The carotid is smaller, thick walled, and can be seen pulsating. The carotid cannot be occluded with Fig. 7.15 Jugular vein compression. Chap-07.qxd 09/Oct/02 11:08 AM Page 313 [...]... the lesion before taking the sample Automated guns are most often used to take the sample The throw of the biopsy needle varies – this is the distance (once fired) the needle advances into the lesion 7 315 Chap-07.qxd 09/Oct/02 11:08 AM Page 316 Ultrasound and intensive care Pre-procedure checks should include platelets, INR and any history of bleeding disorders Platelets of below 50 and an INR of... Chap-07.qxd 09/Oct/02 11:08 AM Page 317 Ultrasound imaging: case illustrations Question 3 44-year-old patient with extensive burns complicated by sepsis (Figs 7.18 and 7.19) Ventilated on intensive care unit Fever, leukocytosis elevated liver enzymes and bilirubin What is the diagnosis? What are the main complications? What are the treatment options? Fig 7.18 Quiz case 7 Fig 7.19 Quiz case 317 Chap-07.qxd... fulfilled by patients on intensive care units Clinical presentation may be non-specific with fever, pain (either right upper quadrant or generalised abdominal pain), leukocytosis and elevated liver enzymes or bilirubin A small proportion of patients with acalculous cholecystitis are made up of outpatients and children Diagnosis is more straightforward in this group On the intensive care unit, it is a difficult...Chap-07.qxd 09/Oct/02 11:08 AM Page 314 Ultrasound and intensive care mild pressure Once the internal jugular is identified using these criteria, then a puncture site can be chosen and a mark made on the skin superficial to this The skin is then cleansed with antiseptic solution and local anaesthetic infiltrated The jugular is then punctured using a introducer needle (18 gauge) and blood is... 148 small bowel infarction 123 splenic laceration 140 abdominal plain X-rays 78–79 bowel gas pattern 78 calcification 78, 96 case illustrations 80–123 solid organs 78 standard views 78 abscess cerebral 244, 245 diverticular 110 intra-abdominal 309 ultrasound-guided drainage 310 liver 96 lung 58, 59, 61 pancreatic 121 plain abdominal X-rays 78 prevertebral 170 psoas 280 retropharyngeal 280 acalculous cholecystitis... 142 colo-colic intussusception 109 colon 82, 84 ascending 80, 81 sigmoid 80, 81 colonic carcinoma 91 colonic diverticular disease 110, 111 colorectal cancer 109 colorectal stent 292 colour Doppler ultrasound 303 common carotid artery 11, 312, 313 compartment syndrome 158, 159 fasciotomy indications 159 competency-based training/assessment xii computed tomography (CT) abdomen see abdominal CT anaesthesia. .. 304 deep vein thrombosis 310, 311 empyema 304 gallstones 304, 305 image formation 302 intensive care unit applications 304–311 intussusception 99, 100 pancreatic disease 305, 306 pleural biopsy guidance 304 pleural effusions 304 renal disease 305, 307 331 Index.qxd 10/ 15/02 7:28 PM Page 332 Index ultrasound (continued) splenic laceration 140, 141 therapeutic applications 309, 310, 311 unconscious patient,... amoxycillin 89 ampicillin 89 321 Index.qxd 10/ 15/02 7:28 PM Page 322 Index 322 amyloid lung disease 61 anaesthesia 258–260 conscious level impaired-patient 224–225 diagnostic radiology 259 guidelines 258–259 magnetic resonance imaging (MRI) 268, 269 children 264 magnetic field strength 266 monitoring 265–266 risks of ferromagnetic attraction 266 post-anaesthetic care 260 radiation protection 259 angiography... arterial pseudoaneurysm 299 arterio-portal fistula 144 arteriovenous malformation intracranial 225, 281–282 intracerebral haematoma 232 pulmonary 55, 56, 61, 284 asbestos exposure 70 asbestos lung disease 70 asbestosis 51 ascites 288, 305, 309 ultrasound-guided drainage 309 aspiration 34 achalasia 101 , 102 neonatal respiratory distress 74 pulmonary oedema 46 see also foreign body aspiration aspirin overdose... clinically and radiologically Delay in diagnosis and the related/predisposing conditions mean that it is associated with a high degree of morbidity and complications Complications include gall bladder perforation, gangrene and emphysematous cholecystitis Ultrasound features include gall bladder wall thickening, gall bladder wall oedema, pericholecystic fluid, intramural gas, gall bladder distention and an . Applications of ultrasound for patients on intensive care units Ultrasound imaging has a huge variety of applications for patients on intensive care units. These include both diagnostic and therapeutic applications,. gallstones on intensive care units can be important in cases of obstructive jaundice, cholecystitis and pancreatitis. Chap-07.qxd 09/Oct/02 11:08 AM Page 305 Ultrasound and intensive care 7 306 Fig bladder drainage.  Pseudocyst/ascitic drainage.  Abscess drainage (see Figs 7.11 and 7.12). Chap-07.qxd 09/Oct/02 11:08 AM Page 309 Ultrasound and intensive care 7 310 Fig. 7.12 Drainage of