The last two weeks, Dr. Cash taught us about bradycardia and transcutaneous pacing. This week, we dug back years into the archives and pulled out Dr. Pelletier-Bui’s famous post on transvenous pacing.
A timeless classic! Just be sure to know what supplies are available in your department, where to find them, and alternate options if your supplies differ.
References:
Bessman, E. (2019). Emergency cardiac pacing. In Roberts et al (Eds.), Roberts and Hedges’ clinical procedures in emergency medicine and acute care (pp. 288-308). Elsevier, Inc.
Dose 0.5 mg IV every 3-5 minutes, up to total dose 3 mg
Can produce paradoxical worsening bradycardia
Less effective in patients with cardiac transplant
Skip if unstable, move directly to pacing
Transcutaneous pacing
Class 1a recommendation
Place pads in anterior lateral or anterior posterior position
Consider sedation or pain control
Set monitor to “Pacer”
Set rate, usually around 60 bpm
Start current at 0 mA and slowly increase until capture is obtained. Consider different placement of pads if capture not achieved by 130 mA
Confirm capture by feeling pulse or cardiac ultrasound
Transcutaneous pacing is ultimately a bridge to transvenous pacing or permanent pacemaker – discuss with cardiology or transfer to center with these capabilities
Capture (pictured below) shows pacer spike followed by a wide QRS and then ST and/or T wave
References:
Judith E. Tintinall, et al. (2020). Tintinalli’s Emergency Medicine : A Comprehensive Study Guide (Ninth Edition). New York: McGraw-Hill.
Doukky R, Bargout R, Kelly RF, Calvin JE. Using transcutaneous cardiac pacing to best advantage: How to ensure successful capture and avoid complications. J Crit Illn. 2003 May;18(5):219-225. PMID: 30774278; PMCID: PMC6376978.
Holger J S, Lamon R P, and Minnigan H J et al.: Use of ultrasound to determine ventricular capture in transcutaneous pacing. Am J Emerg Med. 2003; 21: 227
Revamped from our archives, the fabulous Dr. Alexis Pelletier-Bui teaches us how to use a slit lamp! This comprehensive post reviews all the knobs and buttons of the equipment, then shows how to use it to perform the exam.
COMPONENTS OF THE SLIT LAMP
(These photos are based on a Weiss SL 120 Slit Lamp – other models might be slightly different but the ideas are the same!)
THE VIEWING ARM:
Think of this part as a microscope.
#1 – Oculars – Adjust for your personal interpupillary distance
#2 – Magnification Dial – Can set to 5x, 8x, 12x, 20x, or 32x
#3 – Focusing Ring – Accounts for your personal refractive error. If you have 20/20 vision or correction lenses, it should be set to 0.
THE ILLUMINATION ARM:
This part is your light source. It can be swung 180 degrees side to side to allow for examination from the temporal or nasal side.
#4 – Beam height – Move to the right of examiner > shorter.
#5 – Beam widgth – Move to the right of the examiner > smaller
#6 – Color of light – 3 options: White (used for most of the exam), Cobalt blue (used with fluorescein exam), Green (aka red free filter; allows blood vessels to appear black; rarely used by ED doc)
THE PATIENT POSITIONING FRAME:
#8 – Forehead Strap
#9 – Chin Rest
#10 – Height Adjustor – twist this to raise or lower the chin rest
THE BASE:
#11 – Joystick – Allows movement of the viewing & illumination arms in tandem. Large movements forward & backward are often required to obtain initial focus which will require pressure on the joystick to move the entire base. Smaller microadjustments can be made with smaller movements of the joystick (without moving the base). Movement side to side and up & down (the latter performed by twisting the joy stick) allow for you to examine different aspects of the eye (temporal to nasal, upper to lower lid, etc).
#12 – Light Brightness Knob – Most models have this component on the illumination arm but the Weiss SL 120 has this on the base. Turn right > brighter
#13 – Locking Knob – May need to unlock to move the base. Put the lock on if you are moving the whole slit lamp (i.e. in and out of the patient’s room)
PREPARING/POSITIONING
#14 – Table Height Adjustor – To increase patient comfort (and therefore compliance), lower or elevate the table as needed. You may need to adjust your own chair height accordingly so try to use a stool.
#15 – Power Button – Make sure you’re plugged in!
PERFORMING A SLIT LAMP EXAM:
Step 1: Positioning your patient
Adjust the height of the table to your patient
Make sure the patient’s chin is against the forehead strap or you will be unable to focus the slit lamp
Align the lateral canthus of the patient with the red line on the supporting rod of the patient-positioning frame
Step 2: Position yourself
Adjust your stool so you can comfortably look in the oculars
Adjust the oculars to your interpupillary distance & the focusing ring to your refractive error
Pick your magnification (8x or 12x is a good start)
Step 3: Performing Diffuse Illumination
Move the illumination arm to 30 degrees off center, preferably to the temporal aspect of the eye you are examining (we usually avoid the nasal aspect because the illumination arm tends to hit the patient’s nose with movement of viewing & illumination arms)
Start with a tall & wide (3-8 mm) beam for your initial assessment
Adjust the light brightness to patient tolerance
Utilizing the white light, globally assess the eye with a systematic approach (i.e. the “Ls & Cs” – lids, lashes, lacrima, lens, limbus, conjunctiva, cornea & chamber [anterior])
Stain the eye with fluorescein then examine using the cobalt blue light (assess for corneal abrasions, ulcers, Seidel’s sign, herpes simplex, etc)
Step 4: Perform Direct Focal Illumination
Narrow the beam as thin as possible (~1 mm) but keep it tall
Maximize the light brightness
Move the illumination arm to 60 degrees off center – a curved quadrilateral block should become apparent (aka cornea parallelepiped – see below) – This allows for examination of the depth of the cornea
Move your joystick until the space between the lightsource & the parelleliped is overlying the pupil. The black pupil will allow for visualization of cell and flare (see below).
While most cases of measles are mild and will self-resolve, the high infectivity of the virus is a public health hazard due to rare complications of the disease that can cause long-term morbidity and mortality. Particularly high risk populations include unvaccinated individuals, children < 5 years, adults > 20, pregnant women, and immunocompromised patients.
Look forward to part 2 for more details on measles management, treatment, and complications!
Takhar SS, Moran GJ. Serious Viral Infections. In: Tintinalli JE, Ma O, Yealy DM, Meckler GD, Stapczynski J, Cline DM, Thomas SH. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 9e. McGraw-Hill Education; 2020.
Nguyen M, Dunn AL. Rashes in Infants and Children. In: Tintinalli JE, Ma O, Yealy DM, Meckler GD, Stapczynski J, Cline DM, Thomas SH. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 9e. McGraw-Hill Education; 2020.