y g o o d a R l i Positron emission tomography Molecules labeled with positron-emitting radionuclides are inj ected and postannihilation event photon paths are analyzed by crystal detectors to produce 3-D images. 18F-FDG (fluorodeoxyglucose), an analog of glucose, is the agent most commonly used. Currently, positron emission tomography (PET) is used primarily for the evaluation of recurrent or met- astatic tumors, for assessing tumor response to chemo-/radiotherapy, and for assessing an unknown lesion \200\231s metabolic activity or neoplastic potential (e.g. , a newly appearing lung nodule). Studies are frequently performed in a hybrid PET/CT scann er for accurate physiologic/anatomic correlation. In the brain, 18F-FDG PET can also be use d to determine the site of epi- leptogenic foci when there is no anatomic lesion seen on MR I or CT. PET can also be used to diagnose dementia (even before symptoms start) and 707 to distinguish Alzheimer \200\231s from other dementias (e.g., symmetrical hypo- metabolism in parietal and temporal lobes not the frontal lobes, which are affected in Pick \200\231s dementia). PET development is currently one of the most active areas of research within ra diology, and its indications and uses continue to expand. Organ systems Gastrointestinal radiology Abdominal US Abdominal US has found its major use in suspected hepa- tobiliary disease. It is the choice of imaging for patients who present with acute right upper quadrant pain. It can detect >95% of gallstones and can characterize the gall bladder wall along with localized tenderness (Murphy \200\231s sign) in the case of acute cholecystitis. Note that right upper quadrant and abdominal US require that the pa tient remain NPO 4 \200\2238 h prior to the examination in order to allow the gallbladder t o expand and to minimize abdominal gas. Other clinical indications for hepatobiliary US inc lude evalu- ating obstructive jaundice (dilation in obstructive jaundice; although the caus e, i.e., stone vs. tumor, is less reliably seen), screening for hepatocellular carcinoma in cirrhotic patients (live size, texture [e.g., fatty or shrunken cir- rhotic liver and soli d or cystic masses within it]), evaluating patients before and after liver transplantation (patency and size of the portal vein, spon- taneous or surgically created portosystemic shu nts), and evaluating shunt patency with TIPS. Doppler of the portal and splanchnic veins is used to rule out thrombosis and assess direction of flow in the portal veins in cir- rhosi s, screen for vascular complications after orthotopic liver transplant, and check the paten cy of the stents. Abdominal CT CT is the modality of choice for the evaluation of nearly al l abdominal pathology in both solid and luminal organs. With few exceptions (such as renal stone protocols), abdominal CT should be performed with both oral and IV contrast. This pro vides the most contrast between abdominal structures, allows for evaluation of post-traumat ic injuries (e.g., active hemorrhage, parenchymal organ and hollow organ injuries), infecti ons/abscess, masses, adenopathy, and vascular disease throughout the abdomen. CT can be use d to assess for bowel disease such as obstruction, cancer, perforation/pneumoperitoneum, an d inflammatory/ infectious disease. Figure 18.16 shows CT scans of some acute abdomen patho logies seen commonly in the emergency room. CTA of the abdomen is used for the evaluation o f the aorta, renal arteries, celiac trunk, and superior and inferior mesenteric arteries, a nd can be used to assess for aneurysm, dissection, stenosis, and atherosclerotic disease. A bdominal MRI MRI of the abdomen can be used for the evaluation of masses or infection withi n any of the solid abdominal and, to a lesser degree, luminal organs. MRI is most often use d for the evaluation of lesions that are poorly seen on CT (e.g., metastatic disease to the liver), for the characterization of lesions that are indeterminate with other modalities ( e.g. \200\234complex \200\235 renal cysts or \200\234indeterminate \200\235 liver or adre nal lesions), and for patients who are unable to be evaluated with CT (e.g., allergy to iod inated contrast). MRI is often used to assess the biliary tree (MRCP) to evaluate pancreati c ductal anomalies (e.g., divisum) or for the diagnosis of biliary obstruction. MRA of the abdomen is used for the evaluation of the renal arteries, celiac trunk, and superior and in ferior mesenteric arteries, and of stenosis and atherosclerotic disease. MRA is also used t o assess for arterial dissection or aneurysm. GI fluoroscopy In all of these studies, radio paque contrast (either barium or water-soluble contrast, depending on perforation and aspir ation risks) 708 y g o o d a R Figure 18.16 l i (A) Axial CT with IV and oral contrast demonstrating thickened and dilated appendix ( circl e ) with mild periappendiceal fat stranding. (B) Coronal CT scan with oral and IV contrast demonstrates multiple diverticula in sigmoid colon. There is bowel wall thickening and moderate fat stranding consistent with diverticul itis ( circle ). Images courtesy of Dr. Karen Horton, MD, Johns Hopkins Hospital. is introduced by mouth, feeding tube, or enema in order to evaluate the GI tract. Upper GI series is performed to evaluate the esophagus, stomach, and duo- denum. The upper GI series with small bowel follow-through continues to follow the contrast through the entire small bowel. Indications for these studies include perforation of the esophagus or stomach, gastr ic outlet obstruction, bowel obstruction, GI bleeding, Crohn \200\231s disease (when endos- copy is normal), malabsorption syndromes, and small bowel motility, and for evaluation of surgical anastomosis in a postoperative patient. Barium swallow is a method for investigati ng dysphagia when motility and pharyngeal coordination need to be observed. The patient is asked to swal- low barium containing solids and liquids of various consistencies under dire ct fluoroscopic visualization. It identifies anatomic abnormalities and aspiration. Barium enema is commonly performed with the \200\234double-contrast \200\235 (barium and air) tec hnique that provides a more detailed examination of surface 709 mucosal pattern. Cleansing the colon using a standard bowel prep is the single most importa nt determinant of quality with barium enemas. Indica- tions include demonstration of struct ural lesions (e.g., tumor, diverticula, polyps, ulcers, fistulae, perforation), evaluation of colonic obstruction and as a screening tool for colorectal cancer (CRC) especially in fa iled colonos- copy. Genitourinary radiology Renal US US is the modality of choice to look for urinary tract obs truc- tion (hydronephrosis). It is also useful in detecting chronic kidney disease (echogen ic and small) and in differentiating a benign cyst from a complex cyst or tumor. Renal Dopp ler can be used to evaluate vascular flow and help characterize renal vein thrombosis, infa rction, and renal artery stenosis. Renal CT A noncontrast helical CT scan is the gold stand ard for renal calculi (nearly 100% sensitivity; indinavir stones are not seen) (Figure 18.1 7 ). It can detect those stones that are missed on radiographs as well as on IVP. CT scan c an also detect signs of obstruction (ureteric and collecting system dilation, perinephric f at stranding). Another major use of CT scan in renal pathology is to diagnose and stage ren al cell carcinoma and to characterize renal cysts. Note : A cyst that is simple on US (roun d, sharp boundaries, anechoic, and strong posterior wall echo) doesn \200\231t need further imaging. CT and MRI are being increasingly used for the diagnosis of renal vein thrombosis . Renal nuclear scans A 99mTc-mercaptotriglycylglycine (MAG-3) renal scan can be used to di fferentiate between obstructive and nonobstructive causes of hydronephrosis. 99mTc-DMSA is used to detect scarring in patients with reflux nephropathy. It also detects ectopic renal tissue or renal dysplasia. Pelvic US may be used to assess (1) obstetric pathology \200\224 US is the standard imaging technique for monitoring normal and abnormal pregnancy, fetal gr owth and organ development, localization of the placenta, and ectopic pregnancy; (2) ovarie s (masses \200\224tumors, cysts, torsion); and (3) uterus (masses \200\224fibroids, cysts, endometrial polyps, hyperplasia). Pelvic US in female patients may require transabdominal s can (TA) and transvaginal scan (TV). For a transabdominal scan, a full bladder either from oral intake of water or from filling of the bladder via a Foley catheter is needed. A quant itative serum -HCG should be obtained before all pelvic US per- formed in young women in order to evaluate for ectopic pregnancy because the interpretation of this examination var ies widely depending on the levels of -HCG. CT is usually not the modality of choice for the evaluation of purely pelvic pathology, especially in female patients (i.e., GU origin) . Both US and MRI are more sensitive and specific, have higher resolution within the pelvis , and do not irradiate the gonads. Testicular US Useful for the evaluation of testicular ma sses, infections (epididymitis, orchitis), torsion, and varicocele. Pelvic MRI MRI is a sen sitive and specific modality for the evaluation of both the male and female pelvis. In both men and women, MRI can be used to evaluate for abscess, lymphadenopathy, carcinomas of the colon and rectum, carcinomas of the bladder, and pelvic soft-tissue masses. In the postope rative setting, MRI can be used to distinguish between postoperative changes and tumor recu rrence, and to monitor response to therapy. In the female pelvis, MRI is the modality of ch oice for the evaluation of uterine anomalies (e.g., M (cid:1) llerian duct anomalies, adeno myosis), for the assessment of adnexal masses, and for the radiologic staging of cervical a nd endometrial cancer. It can also be used to evaluate pelvic organ prolapse. In the male p elvis, endorectal MRI is used for staging prostate cancer. 710 y g o o d a R Figure 18.17 Coronal unenhanced abdominal CT demonstrating a left calyceal calculus ( arrow ) l i Note there is no perinephric fat stranding or hydronephrosis. This maybe an incidental find ing in many patients. Thoracic radiology Chest CT CT is the modality of choice for the evaluation of thoracic abn ormalities. Noncontrast chest CT is able to demonstrate small patholo- gies such as focal p neumonias, pleural lesions, and pulmonary nodules that may not be visible using plain radio graphy. High-resolution chest CT is used to assess and diagnose lung parenchymal disease (e .g., emphysema, interstitial lung disease). Contrast-enhanced chest CT is used to evalu- at e lung and pleural masses, as well as mediastinal masses and thoracic adenopathy. CT angiog raphy is the modality of choice for the assessment of pulmonary embolism, aortic aneurysm, and aortic dissection, as well as for post-traumatic assessment when aortic injury is suspe cted. ECG-gated, multidetector CT is also being used to perform coronary angiography and to assess cardiac function. Chest MRI MRI is less sensitive in the evaluation of lung parench yma when compared to CT. However, MRI can be used to assess mediastinal masses, chest wall tumors, and breast masses. MRI and MRA (MR angiography) is frequently used in the evaluatio n of the thoracic aorta for aneurysm and/ or dissection. ECG-gated cardiac MRI is also indi cated for the evaluation of myocardial function, structural/congenital anomalies of the hea rt (e.g., atrial or septal defects), and cardiac tumors (e.g., myxoma). Furthermore, MRI \200\231s abilities to distinguish healthy myocardium from diseased or scarred myocardium a llows for the evaluation of right ventricular dysplasia and hypertrophic cardiomyopathy, an d for the detection of infarcted, stunned, and normal myocardium. Coronary CTA (CCTA) and M RI (CMRI) are rapidly evolving technologies for the noninvasive evaluation of the native co ronary arteries and coronary artery bypass grafts. These noninvasive methods have been foun d to be most clinically applicable in patients with symptoms who are at intermediate risk f or coronary artery disease. Currently, CCTA has a better diagnostic accuracy than CMRI, and CCTA is used clinically on a routine basis. It should be noted that artifacts created by s evere coronary 711 calcification and by coronary stents affect CCTA \200\231s accuracy. CCTA and CMRI can also be used to image congenital anomalies of the coronary artery. Neuroradiology Head CT CT is the first-line diagnostic procedure for intracranial pro- cess es. CT can diagnose hydrocephalus, intracranial hemorrhage, masses/ intracerebral edema, an d cerebral atrophy. Intracranial hemorrhage can be subdural, epidural, subarachnoid, or int raparenchymal and appear differ- ently, as described in Figures 18.18A -E. CT is indicated in the setting of moderate to severe head trauma to assess intracranial structures as well as the cranial bones, and it provides an excellent assessment of the extent and location of intracranial hemorrhage. Fresh blood has higher attenuation and therefore is brighter than the brain parenchyma but, as the hemoglobin breaks down, attenuation of hematomas decline. For example, subacute subdural hematoma at 2 wks will have the same attenuation as the adj a- cent brain. If injury to the face is suspected, a separate facial CT should be ordered t o evaluate for facial fractures and intraorbital pathology. A noncontrast CT is the first c hoice of imaging when a patient is suspected of having a stroke. Although unenhanced head C T is often normal within the first 6 h after ischemic infarction, it should still be ordere d on all patients suspected of presenting with ischemic stroke to assess for the presence o f hemorrhage (a contraindication to the administration of thrombolytic agents), alternative diagnoses (such as intracranial mass), and mass effect and edema that may alter the treatm ent plan. Contrast-enhanced multi- detector CT perfusion and cerebral/cervical angiography is an exquisitely sensitive modality for assessment of acute infarction, as well as for ass ess- ing cerebrovascular embolic sources. The combination of unenhanced and contrast-enhanc ed CT may soon become the modality of choice for the assessment of ischemic infarction due to its widespread availability and speed. Neck CT Contrast-enhanced CT of the neck is usefu l to assess for traumatic damage to either soft tissue or the cervical spine, abscess, neop lasm, and vascular disease (CT angiography). Head and neck MRI MRI is the modality of choic e for the evaluation of tumors and infections of the head (both intra- and extracranially), face, and neck. MRI is also indicated in the evaluation of demyelinating disease (e.g., mu ltiple sclerosis). MRI with diffusion-weighted and perfusion imaging is an exquisitely sens itive modality for assessment of acute infarction and can demonstrate a region of infarctio n within minutes of symptom onset. MR angiography (MRA) can be performed to evaluate the ca rotid and vertebral arteries as well as the circle of Willis for atherosclerotic disease, s tenosis, and aneurysm. MR venography is used for the assessment of venous sinus thrombosis. Spine MRI If neurologic findings related to the spine are present, or if demyelination, in fection, or neoplasm involving the spinal canal is suspected, MRI is the modality of choice for the evaluation of the spinal cord and the surround- ing CSF spaces. If MRI is unavaila ble or contraindicated, CT myelography can be considered. 712 Figures 18.18A-E Types of Intracranial hemorrhage Epidural PADS of Brain Pia Arachanoid Dura Skull Location CT scan of bilateral occipital acute epidural hematomas. Note that there are two lens-shape d hematomas. They arise in the potential space between the dura and the skull. Epidural hem atomas do not cross the suture lines. Trauma resulting in tearing of the meningeal arteries Most common etiology (Continued) 7 1 3 Radiology 7 1 4 Figures 18.18A-E (Continued) Subdural Subarachnoid CT scan of a chronic subdural hematoma. Subdural hematomas form between the dura and the ar achnoid membrane. Note that the attenuation of the hematoma is lower than the adjacent brai n allowing it to be characterized as a chronic hematoma. Trauma resulting in tears of the b ridging veins which cross the subdural CT scan of an acute subarachnoid bleed. Bleeding occurs in the area between the arachnoid m embrane and the pia mater. Ruptured aneurysms space. Intracerebral CT scan demonstrating an acute intraparenchymal hemorrhage within the brain tissue itself. Intraventricular is another subtype of intracerebral bleed that involves the ventricles (no t shown here) Hypertensive vasculopathy Images courtesy of Dr. Nafi Aygun, MD, Johns Hopkins Hospital 7 1 5 Radiology Musculoskeletal radiology Skeletal radiography Radiographic evaluation is often the first m ethod of examination of the extremities and demonstrates fractures, joint effusions, radiod ense foreign matter, and lytic or sclerotic bone lesions. Even if MR and CT are requested f or further evaluation, comparison to plain films is often essential for accurate diagnosis of skeletal abnormalities and will be needed by the radiologist. Spine radiography Although often obtained in acute trauma to assess for acute fracture, multidetector CT has largely replaced spine radiography in this area as it is far more sensitive and specific than radio graphy, and multiplanar reconstructions can be performed. If traumatic spinal injury is str ongly suspected, CT should be the first imaging test obtained, followed by MRI as needed. M usculoskeletal CT CT examination is generally reserved for operative planning for complex f ractures or to further evaluate or characterize osseous lesions. As in other areas of the b ody, contrast-enhanced CT is excellent for evaluating possible soft-tissue abscess in these regions. Spine CT If equivocal plain movie findings or severe pain are present, CT scan to assess the osseous structure of the spinal column should be considered. In most major trau ma centers, cervical spine CT has nearly completely replaced radiography when cervical spin e trauma is strongly suspected. Musculoskeletal MRI MRI is commonly used for the evaluation of joints for ligamentous injury, cartilaginous injury, meniscal tears, or arthritic chang es. It is also the best means for examining bone marrow and soft-tissue masses. MRI is most often ordered for the evaluation of the knees to evaluate meniscal tears, anterior and pos terior cruciate ligament (ACL and PCL) tears, and cartilaginous injury and for degenerative changes. MRI is also the modality of choice for the evaluation of the shoulder joints and is typically ordered for the evaluation of rotator cuff tears or for other traumatic or deg enerative changes in the shoulder. MR arthrography of the shoulder is most useful for the e valuation of labral tears. MRI is used for the evaluation of suspected radiographically occ ult fractures, palpable soft-tissue masses, and in the staging of primary neoplasms of the bone and soft tissue. MR angiography of the extremities can be performed with or without th e use of IV gadolinium for the evaluation of peripheral vascular disease. 716 This page intentionally left blank Practical procedures Rosalyn W. Stewart , M.D., M.S., M.B.A. and Mathew Stewart , M.D., Ph. D. s e r u d e c o r p Contents General considerations 718 Suturing 718 Nasogastric tube insertion 719 Placing an IV cathet er 720 Catheterizing bladders 720 Central venous catheter cannulation 721 Paracentesis 723 Thoracentesis 724 Inserting a chest tube 725 Lumbar puncture 727 Cricothyroidotomy 729 Peri cardiocentesis 730 Cardioversion/defibrillation 731 Inserting a temporary cardiac pacemaker 732 l a c i t c a r P 9 1 There is no substitute for learning by experience. It is better to wait for someone to assi st you with nonurgent procedures when you are not fully confident in your skills than to tr y on your own. Primum non nocere. General considerations \212 Always obtain informed consent; explain the procedure, the indications, risks, and alternat ives. Getting consent for life-saving emergency procedures is not necessary. Universal prec autions should be practiced, and proper sterile technique is essential. Sedation and analge sia, when required, should be planned in advance. Assess for presence of coagulopathy or ne ed to modify medications (e.g., heparin drip). \212 \212 \212 \212 Suturing Assess for foreign body (consider x-ray), deep tissue damage, or injury to nerve, blood vessels, or tendons. Anesthetize wound with topical, local, or regional anesthetic. C lean wound with copious sterile normal saline irrigation. Select suture type, staples, liqu id stitches (if using glue or placing one staple, no need to anesthetize wound). Size is in dicated by a 0, the more 0 \200\231s the smaller (4 \200\2230 is <3 \200\2230). Apply topic al antibiotic (if not using liquid stitches) and sterile dressing; if near joint, immobiliz e with a splint. Consider need for tetanus prophylaxis. 718 s e r u d e c o r p Body region Scalp Face Trunk Extremities Joints Hand Foot Size of suture Staple, or 4, 5 \200\2230 6 \200\2230 4, 5 \200\2230 4, 5 \200\2230 4 \200 \2230 5 \200\2230 3, 4 \200\2230 Removal (days) 5 \200\2237 3 \200\2235 5 \200\2237 7 10 \200\22314 7 7 \200\22310 l a c i t c a r P Nasogastric tube insertion Indication Aspirate stomach contents for diagnosis (e.g., assess for GI bleeding) or treatment (e.g., treatment of ileus, obstruction), or for feeding/medi cation. Contraindications Facial or basilar skull fractures, esophageal stricture, history of caustic ingestion, penetrating cervical spine wounds, choa- nal atresia, recent surgery to upper GI tract, status post esophagectomy, Zenker \200\231s diverticulum. Complications Pain, tracheal intubation, esophagitis, retro- or nasopha- ryngeal necrosis, stomach perfor ation. Equipment Towel or chuck for covering patient \200\231s clothes, emesis basin, nasog astric tube, cup of water and straw, lubricating gel, vasoconstrictor spray, catheter-tip s yringe, stethoscope. Technique 1 Place patient in sitting position, have towels or chuck ov er chest and an emesis basin in lap in case it is needed. 2 For unconscious patient, put the patient in left lateral decubitus position with head tur ned downward. This position helps prevent aspiration. 3 Apply topical anesthetic to nares and pharynx. 4 Select tube by French gauge (F): 16F = l arge, 12F = medium, 10F = small. 5 Estimate length: Put tip at nose, loop tube over ear lobe and then down to xiphoid as wel l as umbilicus. Mark the latter spot with tape before insertion. 6 Spray topical vasoconstrictor. 7 Give patient water with a straw to drink and support the patient \200\231s head to prevent him from pulling away. 8 Insert lubricated tube along floor of nose with the natural curve point- ing down, at a 6 0 \200\22390-degree angle to plane of face, and advance toward occiput. 9 Have patient swallow some water and flex head slightly, when patient swallows, advance tube into esophagus and then into stomach. 10 The patients should be able to speak, if unable, you may have just intu- bated the trach ea inadvertently. Coughing and gagging may also indicate there may be tracheal intubation. 11 Advance to the predetermined distance. 12 Connect a 60 cc catheter-tip syringe to lumen and while auscultating over left upper quadrant, push air into tube. A bubble of air should be heard immediately. 719 13 Secure tube. Placing an IV catheter Ask for help until you are experienced. Equipment IV catheters; gauz e to stop bleeding from unsuccessful attempts; tape and sterile barrier to secure the cathe ter; flush. 1 Set up the first bag of fluid/medication. 2 Explain procedure to patient. Pla ce the tourniquet around the arm. 3 Search hard for the best vein (palpable, not just visib le). Don \200\231t be in a hurry. Rest the arm below the level of the heart to aid venous f illing. Ask the patient to clench and unclench their fist. 4 Sit comfortably, with the patient lying (helps prevent syncope). 5 Tap the vein to make i t prominent. Avoid sites spanning joints. 6 Swab with iodine to clean skin . You may use lo cal anesthetic (or EMLA cream). Use a fine needle to raise a bleb of lidocaine. Wait 15 sec. After IV is placed 1 Connect fluid tube; check flow. 2 Fix catheter firmly with tape. 3 Ban dage a loop of the tube to the arm. 4 Check the flow rate of the infusion. You may need to explain that no needle is left in the arm. If you fail after three attempts or are having trouble putting in an IV \200\224 get help. Hypotensive patients need fluid quickly If the patient needs blood quickly, use a large siz e catheter. \212 \200\234The IV is no longer working \200\235: Ask yourself: Is the IV sti ll needed? Is there fluid in bag and tubing? Is the infusion pump working? Inspect the tubi ng. Are there kinks in the tube? \212Inspect the IV: Take bandage off. Erythematous IV sit es need prompt attention. The catheter should be removed and another placed at a different site. Catheterizing bladders Catheters Size (in French gauge): 12F = small; 16F = large. Usually a 12- or 14F is appropriate. Use the smallest possible. Type: Foley is most commonly used, a flexible tube; coud (elbow) catheters have an angled tip to ease around enlarged prost ates but insertion is more risky. Condom catheters have no in-dwelling parts and therefore cause less pain, less restriction of movement, but they may leak and fall off. Catheter com plications: Bladder infection (don \200\231t use antibiotics unless sys- temically ill). Co nsider bladder irrigation (e.g., 0.9% saline or chlorhexidine 0.02%). Bladder spasm may be painful. Try reducing the volume of water in the balloon. Methods of catheterizing bladders Per urethrae: This route is used to relieve urinary retention, monitor urine output in cri tically ill patients, or collect urine for diagnosis uncontaminated by urethral flora. It i s contraindicated in urethral injury (e.g., pelvic fracture) and acute prostatitis. Cathete rization introduces bacteria into the bladder, so aseptic technique is essential. 1 Check t he catheter \200\231s balloon capacity: Have your equipment set up in easy reach. Place the patient supine in a well-lit area: Women with knees flexed and hips abducted with heels to gether. Use a gloved hand to prep ure- thral meatus in a pubis-to-anus direction, holding t he labia apart with the other hand. With uncircumcised men, retract the foreskin; use a glo ved hand to hold the penis still and off the scrotum. The hand used to hold 720 the penis or labia should not touch the catheter (use forceps to pick-up the catheter if ne eded). s e r u d e c o r p 2 Put sterile lidocaine 2% gel on the catheter tip and 10 mL into the urethra . In men, str etch the penis perpendicular to the body to eliminate any urethral folds that may lead to f alse passage. 3 Use steady gentle pressure to advance the catheter . Significant obstructions encountered should prompt withdrawal and reinsertion. With prostatic hypertrophy, a coud tip cathet er may be required to advance past the prostate. l a c i t c a r P 4 Once inserted fully, wait until urine emerges before inflating the balloon . Pull the cat heter back so that the balloon comes to rest at the bladder neck. 5 Remember to reposition the foreskin in uncircumcised men to prevent edema of the glans after the catheter is inserted. Central venous catheter cannulation Indications \212 \212 \212 \212 \212 \212 \212 \212 Contraindications \212 \212 \212 \212 \212 Emergency access Central venous pressure monitoring Large-volume parenteral fluid administr ation Delivery of parenteral fluids (nutrition, hyperosmolar) Delivery of medications (chem otherapy) Alternative for repetitive venous cannulations Procedures (hemodialysis, plasmaph eresis) Cardiac catheterization, temporary transvenous pacemaker Abnormal or distorted anatomy Bleeding diathesis Burns over insertion site Cellulitis over insertion site If subclavian or internal jugular vein insertion, pneumothorax/hemotho- rax on contralateral side Uncooperative patient \212 Complications Infection, bleeding, arterial perforation, pneumothorax, hemothorax, th rombosis, catheter fracture, air embolism, injury to sur- rounding structures. Equipment \212 \212 \212 \212 \212 \212 \212 \212 \212 Central line kit Sterile gloves, sterile gown, hair cover, mask, eye protection Sterile dra pe Sterile gauze pads Needle driver Suture scissors Suture on a cutting needle Occlusive dr essing Completed x-ray request form if subclavian or internal jugular vein insertion Bedsid e US, such as the Site-Rite system, if available \212 Access locations \212 Internal jugular \212 Subclavian \212 Femoral Technique (Sel dinger technique) 6 Position patient, clean and prep site, drape in sterile fashion; don ma sk, 721 eye protection, hair cover, sterile gown and gloves. 7 Flush central venous catheter with sterile saline; flush all ports. 8 Insert finder needl e while applying negative pressure and locate vessel. 9 Using bedside ultrasound (US), such as Site-Rite system, follow the needle tip indicator to the target vein using the US display. 10 Once blood return is obtained, insert guide wire through needle into the vein. 11 Remove needle while holding onto the guide wire. 12 Enlarge entry site with dilator. 13 Pass catheter over guide wire and into vessel. 14 Remove guide wire. 15 Secure catheter wit h suture. 16 Apply sterile dressing. 17 Obtain a postprocedure central line placement x-ray if subclavian or internal jugular vein insertion. Approaches Internal jugular: 1 Position patient in 15 \200\22320-degree Trendelenburg posit ion. 2 Turn head to contralateral side and hyperextend the neck to tense the sternocleidoma stoid muscle. The internal jugular vein is anterior and lat- eral to the carotid. It travel s under the apex of the triangle formed by the sternal and clavicular heads of sternocleido mastoid muscle and the clavicle. 3 Anesthetize with needle directed toward the ipsilateral nipple and the junction of the medial third and middle third of the clavicle. 4 Puncture skin at this site and direct needle caudally toward the ipsilateral nipple. 5 When blood flow is obtained, continue with the Seldinger technique. 6 The right side is p referred because there is no thoracic duct, there is a straight course to the right atrium, and the dome of the lung \200\231s pleura is usually lower. Subclavian: 1 Position patient in Trendelenburg position with a towel roll under the thoracic spine, between the scapulae to hyperextend the back. 2 Anesthetize at the distal third of the clavicle. 3 Aim needle under the clavicle toward t he sternal notch (see Figure 19.1). 4 When blood flow is obtained, continue with the Seldin ger technique. Femoral: 1 Palpate the femoral artery pulse at the midpoint between the ante rior superior iliac spine and the symphysis pubis. The vein is parallel and immediately med ial to the artery. 2 Anesthetize the skin and subcutaneous tissue. 3 Puncture needle at this site. 4 When bloo d flow is obtained, continue with the Seldinger technique. 722 s e r u d e c o r p Figure 19.1 Right subclavian vein puncture; infraclavicular approach l a c i t c a r P Paracentesis Indications \212 Diagnosis (cytology for neoplasia, culture for spontaneous bacterial peritonitis) Therapeut ic relief from ascites, including relief of pain or respiratory compromise \212 Contraindications \212 \212 \212 Complications \212Bleeding . Rare complication caused by injury to large vessels of abdominal wall, the inferior epigastric vessels, or to mesent eric vessels. Avoid injury to epigastric vessels by staying midline or lateral to the rectu s abdominus. Hemodynamic instability after paracentesis requires emergency investiga- tion and may require an exploratory laparotomy. \212Infection ; ascitic fluid leak may lead to peritonitis. \212Injury to nearby structures including liver or spleen . Bowel and bladder inju- ries most likely. Bowel injuries are minimized by careful technique and patient posi tioning. Bowel injuries lead to delayed peritonitis and sep- sis. Risk of bowel injury duri ng procedures is increased near abdominal scars due to possible adhesion of bowel to previo us abdominal incision. Bladder injuries are minimized by having the patient void or by plac ing a Foley catheter prior to procedure. Coagulopathy Pregnancy Evidence of abdominal wall skin infection or bowel obstruction 723 \212Hypotension from rapid changes in pressure and fluid of abdominal cavity; rarely, by intravascular shift to abdominal compartment. Equipment \212 \212 Paracentesis kit Specimen collection tubes and/or vacuum bottles \212 Intravenous albumin for large volume paracentesis. Technique 1 Place patient in supine position. 2 Preferably, the target site for procedure m ay be determined by US and marked on the patient \200\231s skin. If not available, percuss the ascites, marking a point where fluid level was identified but avoiding scars or vessels . 3 Clean the skin with iodine. 4 Anesthetize skin at the insertion site. The ideal site is m idline, 1 \200\2232 cm below the umbilicus. Do not use a midline site if a previous midline inci- sion is present (due to risk of bowel adhesion to abdominal wall). The lateral site is between the anterior-superior iliac crest and the lateral border of the rectus abdominus , at the level of the umbilicus. 5 Insert a 21F needle on a 20 mL syringe into the skin and advance while aspirating until a scitic fluid is withdrawn. Remove desired amount of fluid. 6 Remove the needle and apply a sterile dressing. 7 If indicated, send fluid for chemistry, microscopy, culture, and cytology. 8 Replace ascitic fluid with albumin if large volume pa racentesis (>4 \200\2235 L) is planned. Replace 6 \200\2238 g (25%) for every liter removed . Can consider replacement for lower volumes removed as well Transudate occurs when a patient \200\231s serum-ascites albumin gap (SAAG) level is \211 1.1 g/dL. Exudative ascites occurs when patients have SAAG levels <1.1 g/dL. Thoracentesis Indications \212 \212 Contraindications \212 Local skin infection, \212 U ncooperative patient Complications Bleeding; infection; pneumothorax; hemothorax; pulmo- na ry contusion or laceration; diaphragm, spleen, or liver puncture; bron- chopleural fistula; reexpansion of pulmonary edema. Equipment \212 \212 \212 \212 \212 \212 Technique 1 Position patient sitting on edge of bed resting head and extended arms on a bedside table. If the patient is unable to sit, place the patient in the lateral decubitus position. Diagnosis (malignancy, infection, inflammation) Therapeutic Thoracentesis kit Sterile gauze pad Iodine Fenestrated drape Oxygen by nasal cannula Specim en collection tubes and/or vacuum bottles 2 Preferably, the target site for the procedure may be determined by US and marked on the patient \200\231s skin. 3 If US marking is not available, confirm location of fluid by percussion, 724 auscultation, and chest x-ray. Mark site with a marker. 4 Locate needle insertion site, 1 \200\2232 interspaces below the fluid level, but not below the eighth rib. 5 Prep and drape area with proper sterile technique. 6 Anesthetize skin and then insert nee dle until it touches the superior border of a rib while aspirating and advancing. Move need le over the superior margin of the rib and anesthetize the intercostal muscle layers. s e r u d e c o r p 7 Insert the thoracentesis needle in the same tract as the anesthesia needle. 8 Draw off 10 \200\22330 mL of pleural fluid. 9 Send fluid to the lab for chemistry (protei n, glucose, pH, lactate dehy- drogenase [LDH], amylase); bacteriology (microscopy and cultu re, acid-fast bacillus [AFB] stain, tuberculosis [TB] culture); cytology. l a c i t c a r P 10 If large-volume removal is needed, use the Seldinger technique and insert catheter through the needle and into the chest. 11 Obtain a postprocedure chest x-ray. A pleural effusion is likely exudative if at least o ne of the following exists (Light \200\231s criteria): \212 \212 \212 Pleural protein-to-serum protein ratio >0.5 pleural LDH-to-serum LDH ratio >0.6 Pleural LDH >0.6 or two-thirds the upper limit for serum LDH Inserting a chest tube NB: This is a sterile procedure. Indications \212 \212 \212 \212 \212 Contraindications \212 \212 \212 \212 Hemothorax, trauma Chylothorax Empyema Effusion Pneumothorax Previous thoracic surgery Pulmonary blebs Oscillator ventilation Prior pleural adhesions Complications \212 \212 Scar formation Injury to lung or surrounding organs \212 \212 \212 Bleeding Pain Pneumothorax Equipment \212 \212 Chest tube kit Sterile gloves, sterile gown, hair cover mask, eye protection Sterile drape Sterile gauze pads Needle driver Suture scissors Iodine 1% lidocaine \212 \212 \212 Scalpel Suture tube: 10 \200\22314F usually; Chest 28 \200\22330F if trauma or hemothorax P leuri-Vac container with water seal Connection tubes Petroleum gauze Occlusive dressing Com pleted x-ray request form \212 \212 \212 \212 \212 \212 \212 \212 \212 \212 \212 Technique 1. Obtain preprocedure x-ray to confirm location for chest tube insertion. 2. Cho ose insertion site: 4th \200\2236th intercostal space, anterior to mid-axillary line, in the \200\234safe triangle, \200\235 see Figure 19.2. \212 A more posterior approach (e.g., the seventh space posterior), may be required to drain a l oculated effusion The second intercostal space in the mid-clavicular line may be used for a pical pneumothoraces. The posterior and anterior approaches are more uncomfortable. 725 \212 \212 3. Infiltrate down to the pleura with 10 \200\22320 cc of 1% lidocaine. \212 Verify that either air or fluid can be aspirated from the proposed insertion site; if not d o not proceed. Wait 3 min for the anesthetic to have an effect. \212 4. Make a 2-cm incision above anesthetized rib to avoid the neurovascular bundle under rib. \212 \212 \212 Blunt dissect with forceps down to the pleura. Puncture pleura with scissors or forceps. If inserting a large-bore tube (>24F), then sweep a finger inside chest to clear adherent lun g and exclude obstructing structures (e.g., in blunt abdominal trauma, stomach in the chest ). 5. Before inserting the chest tube, remove the metal trochar completely and introduce the t ube atraumatically using forceps to advance it. 6. Advance the tip upward to the apex of lu ng (or base of lung if draining an effusion). Stop when you meet resistance. 7. Attach the chest tube to the drainage container with water seal. Ensure that the chest t ube is bubbling with respiration. \212 8. With large-/medium-bore tubes, the incision should be closed with a mattress suture or suture across the incision. \212 Purse string sutures are not recommended as they may lead to scar- ring and increased wound pain. 9. Fix the chest tube with a second suture tied around the chest tube. 10. Cover with petro leum gauze and occlusive dressing. 11. Secure the tube with tape to prevent slippage. 12. O btain a postplacement x-ray to observe the position of the tube. 13. Give PO/IV/IM analgesi a. Tension pneumothorax In a tension pneumothorax air is drawn into the intrapleural space with each breath but cannot escape due to a valve-like effect of the tiny flap in the parie