• In pediatric patients a 20–24 gauge needle may be used for the first cannulation and then exchanged with a larger gauge over a guidewire
• Proceed as described in the standard landmark technique above, but confirmation of the intravenous location of the guidewire with longitudinal view before vessel dilation
Real-time Visualization of SC
• Transducer is placed in the infraclavicular groove at the level of the middle or lateral third of the clavicle
• Axillary vein and artery are imaged as they exit the bony canal formed by the clavicle and the first rib
• Artery is most commonly cephalad to the vein and noncompressible, and does not vary in diameter with respiration
• Either transverse or longitudinal view for guide needle insertion as described above
• Proceed as described with landmark technique followed by confirmation of guidewire location in vein
INSERTION OF A PULMONARY ARTERY CATHETER (PAC) (ALSO SEE CHAPTER 7, ON PERIOPERATIVE MONITORING)
Indications
• Management of complicated myocardial infarction (ventricular failure, cardiogenic shock)
• Assessment of resp. distress (cardiogenic vs. noncardiogenic pulm edema, 1° vs. 2° pulm HTN)
• Assessment of shock
• Assessment of fluid requirements in critically ill (hemorrhage, sepsis, acute renal failure, burns)
• Postop management of cardiac pts
• Need for heart rate pacing
Contraindications
• Tricuspid or pulmonary valve mechanical prosthesis
• Right heart mass (thrombus and/or tumor)
• Tricuspid or pulmonary valve endocarditis
Technique
• Central venous access as described above
• Positioning: Floating PA catheter easier in flat or slightly reverse Trendelenburg in contrast to central line placement (Trendelenburg)
• Aseptic technique: Sterile gown, face mask, gloves, skin disinfection, & whole-body drape
• PAC setup
• Calibrate (“zero”) PAC, check PAC for damage, test balloon inflation/deflation
• Connect all lumens to stopcocks, flush to eliminate air bubbles
• Check PAC tip frequency response by touching tip
• PAC threaded through sterile sleeve prior to insertion into cannula
• PAC inserted percutaneously into major vein (IJ, SC, femoral) via an introducer sheath
• RIJ: Shortest & straightest path
• LSC: Acute angle to enter SVC (compared to RSC or LIJ)
• Fem: Distant sites, difficult if R-sided cardiac chambers enlarged (often fluoroscopic guidance necessary)
• Insert into introducer maintaining preformed curve (RIJ approach: Concave-cephalad)
• Once PAC enters RV, a clockwise quarter turn moves tip anteriorly (allows easier passage into PA)
• After inserting PAC to 20 cm mark (30 cm mark if femoral route used), inflate balloon with air (1–1.5 mL)
• Always inflate balloon before advancing & always deflate balloon before withdrawal
• While advancing, waveforms will be observed (distal lumen pressure monitoring):
• RA ≈ 25 cm (RIJ)
• RV ≈ 30 cm (↑ systolic pressure than RA, absence of dicrotic notch)
• PA ≈ 40 cm (↑ diastolic pressure, ↓ systolic pressure)
• PCWP ≈ 45 cm (some damping & ↓ pressure with occlusion of PA)
• Obtaining pulmonary capillary wedge pressure
• Disconnect breathing circuit
• Determine volume of air in balloon required to obtain a PCWP waveform (volume < half balloon max. may indicate tip too far distal)
• Read PCWP (correlates with LVEDP ≈ 4–15 mm Hg is normal)
• Reconnect breathing circuit, deflate balloon, observe PA waveform return
• PA diastolic pressure usually correlates well with PCWP pressure (should be used as parameter to assess left ventricular filling)
• Withdraw PAC slightly (1–2 cm) to prevent PA rupture from distal tip migration
• Secure catheter sleeve once PCWP is obtained (assure that PCWP pattern is reproducible before removing sterile field)
• Troubleshooting a coiled/knotted catheter:
• Prevention: Withdraw PAC slowly to ↓ risk of knotting catheter upon itself
• Use fluoroscopy if necessary to remove a knot
• Remove PAC & introducer as one unit if unable to release a knot
• Obtain a CXR to check PAC position
Complication: PA Perforation
• Predisposed when no wedge pattern evident after deep insertion
• Circumstances that predispose to PA perforation: Papillary muscle ischemia, mitral stenosis or regurgitation, pulm. HTN, intrapulmonary shunting, LV failure
• Caution if no definitive wedge pattern is observed (repeated attempts to advance PAC may lead to PA perforation)
• Coiling or actual false-negative wedging may occur & predispose to PA rupture
DECOMPRESSION OF A PNEUMOTHORAX (NEEDLE THORACOSTOMY)
Indication
• Tension pneumothorax (symptoms: Hypotension, ↓ SpO2, ↓ breath sounds & tympanic to percussion on affected site; deviated trachea & mediastinum on CXR)
Technique
• Insert large bore cannula or needle into 2nd intercostal space on midclavicular line
• Release pressure in pleural cavity (converts tension pneumothorax → simple pneumothorax)
• Subsequent chest tube insertion usually required to treat pneumothorax
Complications
• Lung laceration (esp if no tension pneumothorax present)
• Reaccumulation of air in pleural space (may be undetected if needle thoracostomy becomes dislodged)
INSERTION OF A NASOGASTRIC TUBE (NGT)
Indication
• Decompression & emptying of stomach (after RSI, prior to laparoscopy, GI surgery)
• Aspiration of gastric fluid (lavage to detect intragastric blood in the setting of GI bleed)
• Tube feeding
• Drug administration
Contraindications
• Base of skull fractures, severe facial fractures (esp to nasal bones)
• Obstructed esophagus or airway
Technique
• Measure tube length (tip of pt’s nose to ear & down to xiphoid process)
• Lubricate end of plastic tube being inserted into anterior nares
• Advance tube through nasal cavity & into throat
• Pass pharynx rapidly with gentle continuous pressure to go into stomach
(if pt awake, encourage patient swallowing)
(if pt asleep, consider use of laryngoscope to visualize entry into esophagus)
• Confirm placement by CXR (safest), aspiration or injecting air (stomach auscultation)
Complications
• Malplacement (endotracheal, intracranial)
• Esophageal perforation
• Pulmonary aspiration, pneumothorax
• Nose erosion/bleeding, sinusitis, sore throat