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Tubes, Lines and Equipment

Sizes, depths and settings you look up at the bedside

Reviewed by Alex G, BSN, RN, CEN, CCRN, CMC, NREMT-P · From the Reference tab of the app

Airway devices

ETT, LMA, cuff pressure, tracheostomy

ETT size, adult	Women 7.0–7.5 mm; men 7.5–8.0; 8.0 or larger if bronchoscopy is likely
ETT depth at the teeth	Women about 21 cm, men about 23 cm; tip 3–5 cm above the carina on x-ray (T2–T4)
ETT size, child	Uncuffed: age ÷ 4 + 4; cuffed: age ÷ 4 + 3.5; depth = 3 × tube size
Cuff pressure	20–30 cm H₂O; check every shift and after moves
LMA size	3 for 30–50 kg, 4 for 50–70 kg, 5 for 70–100 kg
Oral airway	Corner of the mouth to the angle of the jaw
Nasal airway	Nostril to the tragus; avoid in basilar skull fracture
Tracheostomy	Adult 6–8 mm inner diameter; first change after day 7; keep an obturator and a smaller tube at the bedside
Suction catheter	ETT size × 2 for French size (7.5 → 14 Fr); no more than 15 seconds; 80–120 mmHg

Central and arterial lines

Insertion depths and site notes

Right IJ	About 15 cm; tip at the cavoatrial junction
Left IJ	About 17–20 cm
Right subclavian	About 15 cm; left about 17 cm
Femoral	20 cm or longer; higher infection and thrombosis rates
PICC	Measured from the insertion site to the right sternal notch, plus to the third intercostal space
Dialysis catheter	12–16 Fr; right IJ 15 cm, left IJ 20 cm, femoral 24 cm
Arterial line	Radial first (Allen test is unreliable); femoral in shock; level and zero the transducer at the phlebostatic axis (4th intercostal space, mid-chest)
Square wave test	Fast-flush: 1.5–2 oscillations then return = optimal damping; fewer = overdamped, more = underdamped
Maximal barrier	Cap, mask, sterile gown and gloves, full drape, chlorhexidine skin prep; ultrasound guidance
Flush and locks	Saline flush each use; chlorhexidine dressing changed every 7 days or when soiled

PA catheter

Distances and balloon rules

From the right IJ	RA 20–25 cm, RV 30–35 cm, PA 40–45 cm, wedge 45–55 cm
Balloon	1.5 mL maximum; inflate slowly, only to wedge, for no more than 2–3 breaths; let it deflate passively
Normal values	RA 2–6, RV 15–30 / 2–8, PA 15–30 / 8–15, PAOP 6–12 mmHg
Mixed venous O₂ (SvO₂)	60–80% from the distal (PA) port
Cardiac output injectate	10 mL room-temperature saline, injected within 4 seconds at end-expiration; average three within 10%
Alarms	Spontaneous wedge pattern: pull back; RV waveform: catheter slipped back, ectopy risk

Chest tubes and drains

Sizes, suction and removal

Pneumothorax	14 Fr pigtail (seldinger); larger for ventilated patients per team preference
Hemothorax or empyema	28–32 Fr (some use 14–16 Fr for empyema with fibrinolytics)
Insertion site	4th–5th intercostal space, anterior to the mid-axillary line (triangle of safety), over the rib
Suction	−20 cm H₂O usual; water seal only once the lung is up and there is no leak
Removal	Drainage under about 150–200 mL/day, no air leak on water seal, lung up on x-ray; pull at end-expiration or during Valsalva
Mediastinal tubes (cardiac surgery)	Report over 200 mL/h; keep tubes free of clots without stripping

Feeding tubes and catheters

NG, OG, small-bore, Foley

NG/OG length	Nose (or mouth) to earlobe to xiphoid (NEX), plus about 10 cm for the NEMU method
Placement check	X-ray before first use of any blind-placed feeding tube; pH 5.5 or less from the aspirate supports gastric placement; auscultation is unreliable
Sizes	Salem sump 14–18 Fr (decompression); small-bore feeding tube 8–12 Fr with stylet
Post-pyloric	Tip past the pylorus on x-ray; for high aspiration risk or gastric intolerance
Foley	Adult 14–16 Fr; 10 mL balloon; coudé for prostatic obstruction; after surgery remove within 24 h unless still indicated (CDC 2009, SHEA 2022)
Urine output goal	0.5 mL/kg/h or more in adults; 1 mL/kg/h in children
Bladder pressure	Instill 25 mL, measure at end-expiration, supine; 12 mmHg or more is intra-abdominal hypertension, over 20 with new organ failure is compartment syndrome (WSACS 2013)

Defibrillation, pacing and IO

Energy, pad placement, settings, access

Defibrillation	Biphasic 120–200 J (device-specific) or maximum; monophasic 360 J
Synchronized cardioversion	AF 200 J or more; flutter 200 J; other regular narrow 100 J; monomorphic VT 100 J; escalate if it fails (AHA 2025)
Pad placement	Anterior-lateral (right infraclavicular, left mid-axillary at V6) or anterior-posterior; 8 cm from a pacemaker or ICD
Transcutaneous pacing	Demand mode, rate 60–80, start at 10 mA above capture (often 40–80 mA); confirm a pulse with capture
Transvenous pacing	Output 2–3 times threshold (threshold usually under 1 mA); sensitivity 2–3 mV; VVI
Epicardial wires	Atrial wires exit to the right of the sternum, ventricular to the left; insulate the ends when not in use
Intraosseous	Proximal tibia (2 cm below the tuberosity, medial), proximal humerus (fastest flow), distal tibia; any IV drug; pressure bag; lidocaine 20–40 mg for pain in the awake patient; remove within 24 h

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