Friday, May 22, 2009


While rounding with our newest pediatric pulmonologist:

The seven causes of hypoxemia
1. Low inspiratory partial pressure (fraction) of oxygen: high altitude
2. Alveolar hypoventilation: apnea
3. Impairment of diffusion across blood-gas membrane: pneumonia, interstitial disease
4. Ventilation-perfusion mismatch: asthma
5. Shunt: Arterio-venous malformation, mixing cardiac lesion
6. Reduced mixed venous oxygen content in the context of a shunt: not sure
7. Hemoglobinopathy: carbon monoxide poisoning

Abbreviations: FiO2, a's and b's, a-A gradient, dz, V-Q mismatch, AVM, CO, ddx

Sunday, May 10, 2009

Calcium Metabolism: Hypocalcemia

Recognize the signs and symptoms of hypocalcemia

Add this to your differential, guys: hypocalcemia generally makes you more prone to tetany, which is the term for muscle contractions due to neuromuscular excitability. Usually we think of tetany as sustained contractions in the hands, feet, or face, but hypocalcemia can also present as cyanosis or stridor from laryngospasm. So think about it the next time you see croup!

Abbreviations: ical, ca, ddx
Mnemonic: Low cash (Calcium) makes your face twitch (tetany)

Friday, May 8, 2009

Journal Club: Be Mean

Evidence-based medicine is a process. First, investigators test therapies against each other, against nothing, try different tests, frenzy themselves with recruiting patients for one study after another. Others follow after patients, trying to figure out if this sized liver is normal or if it goes bad in ten years. The various studies and types of studies pile up. Then, a clinician, with a patient, tries to read through it all and make the best decision for the individual patient. To do that she needs to be critical of the studies from conception to completion.

In residency, we try to be nice to each other. Life is tough; we try not to make it worse. We support growth and change and sometimes simple survival through the worst of the season. Today, though, I learned that when it comes to studies, I need to be mean.

Abbreviations: EBM

Persistent Sleep Apnea after Tonsillectomy & Adenoidectomy

While rounding with one of our pediatric pulmonologists:

It often takes 6-8 weeks before someone with obstructive sleep apnea recovers enough from tonsillectomy & adenoidectomy to be eligible for repeat sleep study. Follow-up with pulmonology in two months. If they had problems with low oxygen saturation overnight, consider discharge with home oxygen for sleep, though then they will need to have a sleep study to document that they can stop that.

Abbreviations: T&A, OSA