46. Central venous access
General considerations Central venous pressure monitoring, administration of pressors, inotropes, poor peripheral access, long-term anticipation of IV meds, hypertonic solution (TPN), HD (CVVH) or plasmapheresis, Swan-Ganz catheterization, transvenous temporary cardiac pacing. Contraindications. Controversial, technically there is no absolute contraindication to a central line. Consider vein thrombosis, coagulopathy, untreated sepsis. Scheduled, routine exchange catheters generally not indicated (see meta analysis published in Crit Care Med 1997;25:1417 shows no benefit). Subclavian lines have lowest risk of infection, though no head-to-head comparison of subclavian v. internal jugular (see JAMA 2001;286:700). Technique Position of catheter Position patient supine and Trendelenburg (to engorge Catheters should terminate in distal veins, maximize target, and minimize risk of air inominate vein or proximal superior vena embolus). cava, 3-5 cm proximal to junction of SVC Use prep solution on stack of gauze pads to prep area and right atrium. wide using circular motion in to out on last pass. Right sided insertions, caval junction is Anesthetize area with lidocaine (aspirate as you about 13 to 16 cm from right-sided IJ or inject) including the periosteum in the case of subclavian skin punctures subclavian line, which can be most sensitive. Drape Caval junction 15 to 20 cm from left-sided sterile field wide, cover patient up as much as insertions possible so you can place all of your equipment on the sterile field. Flush all lines using heparinized saline (contraindicated in patients with HIT) in blue sponge bowel and clamp off. Advance needle finder slowly, aspirate at all times, even when withdrawing. After flash of blood is seen in locator, draw back to ensure good flow and dark coloration. If arterial, remove and compress 5-10 minutes. If air is drawn back, then pneumothorax is likely if IJ/subclavian, will need stat chest x-ray, decompress if tension. Remove the syringe from locator and stabilize the needle with one hand. Feed the wire in (J-shaped end). If you meet any resistance, draw back wire and assess for adequate flow with syringe and re-attempt. If you induce any ectopy, this is may be a good sign that you are in the RA/RV, especially if LBBB pattern; just withdraw back into the SVC. Once wire is threaded, do not let go of the wire. Withdraw the needle, extend the puncture site with one stab of scalpel 1/3 buried. Then run catheter over wire (Seldinger technique), see below for position of catheter. Use syringe to pull back a tinge of venous blood and flush all ports. Clamp off all ports and place green caps on prior to sewing into skin with two simple stitches. Order stat chest X-ray to assess positioning, rule out pneumothorax, hemothorax Subclavian vein Advantages Disadvantages Anatomy is more reproducible even in obese patients given Highest risk of pneumothorax (1-8%). Left side is slightly bony landmarks higher than right due to higher dome of left pleura Improved patient comfort; greater ease of dressing and Not easily compressible site (can compress with two fingers maintenance though) Lowest incidence of infection Subclavian artery puncture/hemothorax risk 0.5-1% (supra MGH Medical Housestaff Manual 109 46. Central venous access There are two different approaches to the subclavian: supraclavicular (2) and infraclavicular (1). Some people like to place a roll of towels between scapula to expose subclavicular area, but others say this may distort anatomy. Infraclavicular approach Entry. Three traditional entry sites, but the technique is the same regardless: Median. 1 cm inferior to the junction of the proximal one-third and distal two-thirds of the clavicle and directed toward the suprasternal notch. Middle. 1 cm below the midpoint of the clavicle. Lateral. 1 cm below the junction of the proximal two-thirds and distal one-third of the clavicle. Catheter malposition in the internal jugular vein is less common with this approach, but the risks of subclavian artery puncture and brachial plexus injury are increased. Target. Bevel up. Keep the needle horizontal, parallel to the floor, at all times and aim toward the suprasternal notch. The needle should advance just on the underside of the clavicle. Some people like to “walk down” the clavicle to ensure this; this may lead to dulling or bending of needle. Depth of puncture. 3 cm but variable Supraclavicular approach: Entry. Bevel up. Angle formed by the lateral margin of the SCM and the clavicle. Target. Bisect the angle and aim level to 10 degrees toward the contralateral nipple. The needle should advance just underneath the clavicle. Depth of puncture. 2-3 cm Pearls Turning the patients head to ipsilateral side while kink the IJ and facilitate the wire going down the SVC. Rotate the bevel 90 degrees caudal to help direct the wire into SVC (3 o’clock position), away from IJ or opposite subclavian; in the case of supraclavicular approach rotate to 9 o’clock. The subclavian can be compressed with two fingers squeezing around the clavicle. Internal jugular vein Advantages Disadvantages MGH Medical Housestaff Manual 110 46. Central venous access Lower risk of pneumothorax (<1%) than subclavian Carotid artery puncture 2-10% Compressible Less patient comfort in neck mobility, ease of maintenance than subclavian Lower incidence of catheter colonization and bacteremia Anatomy not as consistent as subclavian (though not significantly less than femoral) Anterior approach Lateral approach Median approach There are three approaches to the IJ: anterior, central (middle), and posterior The anterior approach has the highest incidence of carotid puncture and pneumothorax, whereas the posterior has the least of both. For all, the carotid should not be retracted as the vein is collapsible. Furthermore, the vein is actually superior and slightly lateral to the carotid, rather than purely lateral. The right side is preferred given its direct course into the SVC, and left IJ approach has added risk of thoracic duct laceration and left brachiocephalic vein puncture. Anterior approach Entry. Bevel up. Medial to sternal head of SCM about 4-5 cm above suprasternal notch. Target. Ipsilateral nipple at 45 degrees. Depth of puncture. 5 cm. Central approach Entry. Bevel up. Split the two heads of the SCM at the vertex. Target. Ipsilateral nipple at 45 degrees. Depth of puncture. 5 cm Posterior approach Entry. Bevel at 3 o’clock. Lateral border of clavicular head of SCM about 4 cm above suprasternal notch. This is usually 1 cm superior to intersection with EJ. Target. Suprasternal notch at 45 degrees to sagittal plane and 15 upright. Depth of puncture. 5-7 cm Pearls Rotating the head may actually compromise the anatomy. MGH Medical Housestaff Manual 111 46. Central venous access Using bedside ultrasound can be helpful to locate the IJ. Femoral vein Advantages Disadvantages No risk of pneumothorax Femoral artery puncture 5-10% Compressible Deep venous thrombosis Can be cannulated during CPR. Less patient comfort in hip flexion Equal incidence of infection to IJ, but higher than Caution in placement in patients with inferior vena cava subclavian (see also JAMA 2001; 286:700) filters. Entry. Bevel up. 2-3 cm below inguinal crease/ligament, 1-2 cm medial to palpated pulse, i.e. the femoral vein lies medial to the femoral artery. Target. Directly superior/cephalad at 30-45 degrees Depth of puncture. 2-4 cm Pearls Vein is medial to artery Approaching above the inguinal ligament puts the patient at risk for retroperitoneal bleed, peritoneal perforation. Troubleshooting and complications Arterial puncture Usually obvious but may be missed in a patient who is hypoxic or hypotensive. Consider bedside comparison of blood withdrawn from line with simultaneous arterial blood. If unsure, transduce the waveform or send an ABG. Withdraw the needle and apply firm direct pressure to the site for at least 10 minutes or longer if there is continuing bleeding. If there is minimal swelling then retry or change to a different route. Suspected pneumothorax Suspect pneumothorax if air is easily aspirated into the syringe (note that this may also occur if the needle is not firmly attached to the syringe) or the patient starts to become breathless. Abandon the procedure at that site. Obtain a chest radiograph MGH Medical Housestaff Manual 112 46. Central venous access and insert an intercostal drain if confirmed. If central access is absolutely necessary then try another route on the same side or either femoral vein. Do not attempt either the subclavian or jugular on the other side to prevent the possibility of bilateral pneuomothoraces. Arrhythmias during the Usually from the catheter or wire being inserted too far (into the right ventricle). procedure Withdraw the wire or catheter if further than this. Air embolus This can occur, especially in the hypovolemic patient, if the needle or cannula is left in the vein while open to the air. It is prevented by ensuring that the patient is positioned head down (for jugular and subclavian routes) and that the guide wire or catheter is passed down the needle promptly. The wire will not thread down Check that the needle is still in the vein. Flush it with saline. Try angling the the needle needle so the end of it lies more along the plane of the vessel. Carefully rotate the needle in case the end lies against the vessel wall. Reattach the syringe and aspirate to check that you are still in the vein. If the wire has gone through the needle but will not pass down the vein it should be very gently pulled back. If any resistance is felt then the needle should be pulled out with the wire still inside, and the procedure repeated. This reduces the risk of the end of the wire being cut off by the needle tip. Never use the opposite end of the wire as this can puncture through the vein. Persistent bleeding at entry site Apply firm direct pressure with a sterile dressing. Bleeding should usually stop unless there is a coagulation abnormality. Persistent severe bleeding may require surgical exploration if there is an arterial or venous tear Roderick Tung, M.D. MGH Medical Housestaff Manual 113 47. Lumbar puncture Indications Diagnostic. CSF analysis and sampling (rule out CNS infection, meningeal carcinomatosis, subarachnoid hemorrhage, CNS demyelinating/inflammatory process) and measuring opening pressure Therapeutic. Used in pseudotumor cerebri, normal pressure hydrocephalus. Contraindications. Skin infection over puncture site (absolute), increased ICP (abscess, mass, hydrocephalus, papilledema) risks herniation, known spinal cord tumor, AVM, severe bleeding diathesis, platelets <50,000. Note that recent study in JAMA 2000;284:2222-2224 suggested that serious complications associated with lumbar puncture in children with ALL and thrombocytopenia are generally not observed N Engl J Med 2001;345:1727 suggest criteria associated with abnormal head CT: age of at least 60 years, immunocompromise, a history of CNS disease, and a history of seizure within one week before presentation, abnormal neuro exam including abnormal level of consciousness, an inability to answer two consecutive questions correctly or to follow two consecutive commands. Technique Equipment in clean utility. Lumbar puncture tray includes lidocaine/syringe, sterile field, 20 G needle/stylet, 4 collection tubes, iodine swabs, manometer. There are two positions utilized in LP, lateral decubitus and upright sitting position (preferred in obese patients). Prep and drape the area—either L3-L4, L4-L5 (level of iliac crests), L5-S1 interspaces can be used. Palpate for the most open interspace. Conus medullaris is at L1-L2. Proper positioning is key. Have the patient maximally assume fetal positioning with head flexion and knees to the chest. spinal needle is inserted usually between the 3rd and 4th lumbar vertebrae Attempt to optimize spinal alignment and palpate the vertebral processes to identify midline. Anesthetize the skin and deeper into the lumbar fascia. If periosteum is reached, inject as well as it can be extremely sensitive. Introduce needle using both index fingers and thumbs, with stylet (to maintain patency of needle and reduce risk of introducing epidermoid cells into thecal sac). Orient bevel upwards if patient is lying in lateral decubitus; decreases severing of dural fibers and reduces incidence of post-LP headache. Once the skin is penetrated, aim toward umbilicus as this follows the angle of intervertebral space. Ensure that your approach is parallel to the ground. Advance slowly and after 3 cm, check every 1-2 cm advance by removing stylet and assessing for flow at the hub. A “pop” can be felt when the dural sac is penetrated but not necessarily so. Depth of puncture ranges depending on body habitus from 3 cm to hub. Keep stylet in needle whenever advancing or withdrawing needle Once flow is established, remove stylet and first measure opening pressure with manometer. Have the patient straighten out their legs for fluid measurement as it can falsely elevate your opening pressure. Collect samples for tubes 1-4: Tube 1 and tube 4. For hematology. Cell count MGH Medical Housestaff Manual 114 47. Lumbar puncture Tube 2. For chemistry. Total protein, glucose. Tube 3. For microbiology. Gram stain, culture. Consider HSV PCR, cryptococcal antigen, viral culture, AFB stain, VDRL. Fill this tube the highest as it can be stored in the microbiology laboratory for additional studies Additional tests include cytology (to evaluate for meningeal carcinomatosis), oligloclonal bands (seen in multiple sclerosis), paraneoplastic antibodies. Troubleshooting and complications Tonsillar herniation Remove needle immediately. Place patient in reverse Trendelenburg. Protect airway and hyperventilate if needed. Call neurosurgery immediately. Nerve root injury Shooting pains are usually transient and nerve roots will be brushed aside by needle. Withdraw/remove needle. Administer dexamethasone if pain is persistent. Post-LP headache Reported incidence variable 1-70%. Thought to be secondary to dural leak with traction- postural. Typical onset within 72 hours lasting 3-14 days. To minimize risk use smaller gauge needle. IV caffeine is the drug of choice. If persistent, call anesthesia/pain for epidural blood patch. No data for hydration, lying recumbent after lumbar puncture for reducing post-LP headache (Neurology 2000;55:909-914). Hemorrhage Case reports in setting of coagulopathy: subarachnoid spinal hemorrhage and subdural hematoma. High mortality. Call neurosurgery immediately. Rare: hearing loss, CN VI palsy Transient phenomena. Interpretation CONDITION PRESSURE WBC/µL CELL TYPE GLUCOSE PROTEIN ORGANISM cm H2O mg/dL mg/dL normal 9-18 0-5 lymph 50 – 75 15-40 none bacterial 20-30 100-5K >80% PMN <40 100-1000 Gram stain + in 60% meningitis culture + in 80% brain abscess 18-30 10-200 lymph normal 70-400 brain abscess 20-30 1K-50K PMN <40 200->500 anaerobes with leak into ventricle subdural 20-30 10-2K lymph>PMN unless low to normal 50-500 empyema meningitis epidural 18-25 10–300 lymph normal 50-200 abscess cortical vein 18-25 10–300 lymph or PMN normal 50-200 septic phlebitis TB meningitis 18-30 <500 lymph <50 100-200; 1000 If M. tb is not in if CSF block lumbar CSF, tap present cistern cryptococcal 18-30 10–200 lymph <40 50-200 antigen and culture meningitis viral 9-20 10–300 lymph; early echo normal ; low in 50-100 LCM, HSV 2 and meningitis can have 80% PMN LCM and mumps HIV Roderick Tung, M.D. MGH Medical Housestaff Manual 115 48. Thoracentesis Indications Diagnostic. Unestablished etiology of pleural effusion. Therapeutic. Drainage for respiratory compromise. Contraindications. Coagulopathy. Active skin infection over site of entry, loculated (no layering on decubitus; consider IR guidance), small size effusion (<1 cm thickness from chest wall on lateral decubitus), portal hypertension because of increased risk of pulmonary varices. Mechanical ventilation does not increase the risk of pneumothorax, but does increase the risk of tension pneumothorax Technique Position the patient seated upright on bed with head and extended arms rested on bedside table and percuss; entry should be 1-2 interspaces below this level. Lowest level recommended is eighth intercostal space. Highest level is generally chosen to minimize abdominal penetration (spleen, liver, diaphragm laceration). Prep and drape the area. Anesthetize the local skin down to the periosteum, which is most sensitive. The posterior approach should be parallel to the floor, midline, which is marked by the tip of the scapula. Advance the needle slowly while aspirating at all times over the superior edge of the rib; the neurovascular bundle lies on the undersurface of the rib. Avoid using needles as large as 14 gauge; increased risk of pneumothorax requiring chest tube placement (Arch Intern Med 1990; 150:873) Alternative approach is midaxillary or posterior axillary line entry in the fourth or fifth intercostal space while the patient is in a supine position; this has higher failure rate and increased risk of parenchymal injury. Once fluid is withdrawn, do not advance any further; stabilize the needle. If flow stops, the catheter can be advanced 1-2 mm at a time, bevel rotation can be attempted. For therapeutic drainage, withdraw needle and advance angiocatheter. Connect the angiocath to the tubing and puncture the other end into vacuum bottle. When sample is obtained, withdraw needle while patient exhales. MGH Medical Housestaff Manual 116 48. Thoracentesis Troubleshooting and complications Hemothorax/Intercostal Only if approach was inferior to rib. Follow serial CXR for hemothorax from laceration. vessel damage Pneumothorax 5-20% risk. Look for signs of tension PTX and obtain stat expiratory CXR. If clinical suspicion is high, immediate needle decompression should be undertaken- 2nd intercostal space midclavicular line. Chest tube thoracostomy indicated in about 20% of cases. Pulmonary To avoid reexpansion fluid shifts, avoid removal of >1-1.5 L at one time. edema/hypovolemia Interpretation Send fluid and draw serum for Light’s criteria parameters: protein, LDH Light’s criteria. If one or more present, effusion is exudate. Pleural fluid protein/serum protein >0.5 Pleural fluid LDH/serum LDH >0.6 Pleural fluid LDH >2/3 upper limits of normal for serum LDH Other studies Cholesterol >45 mg/dL 89% sens, 81% specific for exudates (Chest 1997;111:970) Albumin, serum-pleural effusion gradient >1.2 g/dL suggestive of transudate (e.g. “diuresed effusions from CHF) (Am J Med 2001;110:681) Also consider cytology, cell count, glucose, pH, cytology, amylase, rheumatoid factor, ANA Tuberculosis, culture 25% sensitive, 100% specific; pleural biopsy 90% sensitive. Pleural effusions generally total protein >4 g/dL Malignancy, cytology and biopsy 68% sensitive, 100% specific Sensitivity for malignancy not dependently on volume; 10 cc of fluid appears adequate (Chest 2002;122:1913) Infection, no absolute WBC criteria can exclude infection If pH 7.0-7.2 or LDH>1000: do serial taps to assess need for chest tube. Chest tube indications Sclerotherapy for malignant effusions or large recurrent effusions Complicated parapneumonic: pos gram stain, pH <7.0, glucose <40, gross pus Roderick Tung, M.D. MGH Medical Housestaff Manual 117 49. Paracentesis Indications Diagnostic. New onset ascites, unestablished etiology of ascites, rule out spontaneous bacterial peritonitis (SBP). Therapeutic. Large volume paracentesis (LVP), performed for abdominal pain/discomfort, respiratory compromise, adjunctive treatment of esophageal variceal bleeding; can lower portal/variceal pressures. Contraindications. Acute abdomen requiring surgery, infection overlying the site, inability to demonstrate ascitic fluid on bedside examination, 2nd or 3rd term pregnancy, bowel obstruction, DIC. Coagulopathy (PT elevation), thrombocytopenia are not absolute contraindications; 70% of patients with ascites have abnormal PT, and hemorrhagic complications of paracentesis uncommon. Generally not necessary to correct coagulopathy with fresh frozen plasma. Technique Site of insertion, percuss to ensure presence of mobile fluid. Infraumbilical, midline approach, 2 cm below. Linea alba is avascular; position patient with head of bed elevated or lateral decubitus as bowel may float up and away from site of entry McBurney’s point (LLQ preferred over RLQ given cecal distention). Lateral to rectus muscle has higher risk of epigastric vessel puncture (not shown in diagram). For diagnostic paracentesis, use 22 G needle. An 18 G angiocatheter is preferable for large volume paracentesis. Prep and drape site wide. Anesthetize area with lidocaine. Avoid engorged superficial veins as well as prior surgical incisions (increased risk of bowel adhesion). Introduce angiocatheter attached to syringe at oblique angle, aspirating gently at all time (higher suction may attract bowel). Use the Z line tract approach: pull skin approximately 2 cm caudad in relation to the deep abdominal wall by the non-needle-bearing hand while the paracentesis needle is being slowly inserted. Release the skin when the needle has penetrated the peritoneum and fluid flows. When the needle is removed following the procedure, the skin will slide to its original position and help seal the tract. Once fluid is withdrawn (usual depth of puncture is 1-2 inches), do not advance any further and stabilize the needle. If flow stops, the catheter can be advanced 1-2 mm at a time, bevel rotation can be attempted, or MGH Medical Housestaff Manual 118 49. Paracentesis patient can be rotated to allow for more dependent fluid accumulation. For therapeutic LVP, withdraw needle and advance angiocatheter. Connect the angiocath to the tubing and puncture the other end into vacuum bottle. A-line tubing with male-male Luer locks helpful (can be obtained from Blake 8) Consider colloid replacement with albumin (SPA), i.e. 10 g of albumin per L of ascites fluid removed for patients undergoing large volume paracentesis. Troubleshooting and complications Bowel perforation Usually not recognized at time of procedure. Leads to sepsis/peritonitis, worsening ascites. Needs surgical consult for secondary peritonitis/laparotomy Hemorrhage Due to injury to mesentery or inferior epigastric vessels. Usually self-limited, if hemodynamically significant, laparotomy is indicated Hypotension Likely vasovagal or fluid shift (>1500 cc tap). Hydrate and consider albumin (SPA). Skin leak Usually heals within 2 wks; can increase risk of peritonitis. Can use a figure 8 stitch to close skin. Tubing collapse Use a 3-way stopcock on the angiocath to diminish/control pressure or use more rigid A- line tubing. Bladder perforation Call urology; place Foley to decompress bladder. Bladder decompression prior to procedure dramatically decreases risk. Diagnostic assays Cell count and differential, Gram stain, aerobic and anaerobic blood culture bottles for routine culture (10 mL per bottle, inoculated at the bedside). Total protein, albumin and simultaneous serum albumin. Also consider glucose, amylase, LDH, adenosine deaminase (elevated in TB peritonitis). Interpretation In ascites secondary to portal hypertension, cell count >250 PMN/L and positive ascites culture diagnose SBP. Serum-ascites albumin gradient 1.1 g/dL indicates portal hypertension (cirrhosis, cardiac, massive liver metastases, hepatocellular CA, “mixed”); <1.1 suggestive of peritoneal carcinomatosis (liver, ovarian CA), TB peritonitis, malnutrition, or a biliary, pancreatic, or nephrotic syndrome etiology. Refer to Runyon in Ann Intern Med 1992; 117:215 and in Hepatology 1998;27:264. Roderick Tung, M.D. MGH Medical Housestaff Manual 119 49. Paracentesis Method Take care not to tap through an infected area thus introducing infection into joint space If patient has less pain with extension and more pain with flexion without decreased joint mobility, it may be bursitis and not a joint effusion Hip joint generally requires aspiration under fluoroscopy (consult bone radiology) Knee arthrocentesis (lateral approach) Place the knee in an extended position. Palpate the superior lateral aspect of the patella, and then move 1 cm lateral and 1 cm superior to this site. Using 25 G needle, anesthetize the skin and subcutaneous tissues up to the synovium with 1-2% lidocaine (without epinephrine) and then cleanse skin with povidone iodine. Insert a 21-22 G needle directed at a 45 degree angle distally and 45 degrees into the knee tilted below the patella, aspirating while advancing. Once the needle has been inserted 1-1.5 inches, the syringe should fill with fluid. If infection is considered, an 18G needle may be necessary to remove viscous fluid. You may need to change syringes to collect all of the fluid, holding the needle in place with a hemostat while replacing the syringe. Fluid analysis Send glucose, WBC and differential, gram WBC Polys Glucose stain, cultures, crystal analysis Normal <200 <25% serum Urate crystals are strongly negative Non-inflamm. <2,000 <25% serum birefringence, yellow, needle-shaped (OA, trauma) Calcium pyrophosphate dihydrate crystals Inflamm. (RA, 2,000- >50% 25 < joint < are weakly positive birefringence, blue, crystal, seroneg) 100,000 serum rhomboid-shaped Septic Usually > >75% <25 Presence of crystals does not exclude 100,000 infection. Gram stain: 75% positive if Staph, 50% pos if gram negative rods, <25% positive if gonococcus. Cultures: joint usually positive in non-gonococcal arthritis, only 50% positive in GC arthritis if inoculated at the bedside. Blood cultures positive in 50% of non-GC and positive in 20% in GC arthritis. Non-gonococcal adult septic arthritis 70% Staph, 17% Strep, 8% gram negative rods, H. influ. child > adult If arthritis is chronic and monoarticular, consider tuberculosis. Sites of adult septic arthritis Knee > hip > shoulder > elbow. If sternoclavicular joint involved, consider IV drug use or pre-existing joint disease. Alyssa Johnsen, M.D., Ph.D. MGH Medical Housestaff Manual 120