Bipap Settings

BIPAP Principles:This one goes out to our rising Resus Residents: Bipap has settings that can ameliorate the two primary causes of respiratory failure: oxygenation (CHF, pneumonia) and ventilation (COPD, etc).

Improve hypoxemia two ways: 1. FiO2 2. PEEP (recruit more alveoli) Improve ventilation (hypercarbia) 1. Tidal Volume 2. Respiratory Rate

Settings on Bipap: IPAP – Inspiratory positive airway pressure (e.g. the high number) EPAP – Expiratory positive airway pressure (e.g. the low number) FiO2 – Fraction of inspired O2 (%) There are more, mentioned below, however lets touch on these first.

It is important to understand the cause of your respiratory failure to apply the proper settings. Physiology! Time to move on to practical application:

For HYPOXEMIA generally start with IPAP of 10cmH2O. EPAP can generally start at 5cmH2O

Example:

• CHF (hypoxemia): Start at IPAP of 10cmH2O with an EPAP of 5cmH20 (remember you want EPAP here to prevent atelectasis. o Pressure will improve oxygenation o May always increase FiO2 as well to improve oxygenation Conversely, for HYPERCARBIA (COPD) start with a similar IPAP of 5-10cmH20 however EPAP may not even be necessary. o Remember the difference in IPAP and EPAP is related to tidal volume, and this is one thing that effects hypercarbia!! Greater the difference = greater tidal volume. o You may also change the respiratory rate (described below)

Other settings/points: • Respiratory rate as well as I:E (inspiratory:expiratory) ratio can also be adjusted (however these settings may or may not be as helpful in a patient who is breathing on their own). I don’t want to get into this too much, but a couple points: • For HYPERCARBIA increased ventilation is desired with a HIGHER respiratory rate to blow off CO2. • For asthma keep EPAP lower (blow out more air in expiration) and setup a lower I:E ratio (e.g. 1:5) to prevent “breath stacking.” • Titrate by 2 – 3 cmH20 every 5 – 10 minutes. • Max IPAP is generally considered 20cmH2O (this is because lower esophageal sphincter tone is roughly 23 – 25cmH20, don’t over insufflate the stomach). • Remember to get a blood gas.

Sources: JB Life in the Fast Lane Rebel EM UpToDate

Fragile Skin Tears

Today we are going to try to focus on a practical skill which is increasingly important with our aging population: Fragile Skin Tears. Hemostasis/Pain Control:

• Pressure

• Use LET (Lidocaine-Epinephrine-Tetracaine)!

• Topical TXA

• Surgicel

Suture Techniques:

1. Apply a couple deep sutures to appose the wound edges. Then place steri strips across the wound and suture through them with 4.0 nylon sutures. This places tension on the tissue below rather than just on the skin.

2. Place steri-strips parallel to the wound and suture through the steri strips with 4.0 nylon suture. Similar to approach above, however you are able to visualize the wound edges.

3. Derma-Bond AND Steri Strips. Perform the above techniques, however derma-bond the edges of the wound, let dry, and place sutures through both the steri strips and derma bond. This will be the effective technique for preventing shearing of extremely fragile skin.

Note there are many variations to this, you may also throw sutures behind the glue. Glue alone may work better for jagged edges than steri-strips. 

1. Mattress sutures, tegaderm and wait etc.

Aftercare

When the steri strip techniques are used, try to keep wound dry (rather than using topical antibiotics such as bacitracin which will cause the steri strips to become ineffective.  Patients should be vigilant for signs of infection.

Sources:

EMDocs

Lacerationrepair.com

Aliem

Search Terms: Elderly Skin Parchment Laceration Fragile Skin Laceration Tear

Pearl of the Day: Complications of Vascular Access for Hemodialysis

Complications of Vascular Access for Hemodialysis- more frequent with autologous vein, polytetrafluorethylene, or bovine carotid artery graft (as opposed to native artery or vein) - account for more inpatient hospital days than any other complication of hemodialysis

Thrombosis and Stenosis - most common causes of inadequate dialysis flow (<300 mL/min) - grafts have higher rate of stenosis than fistulas - signs: loss of bruit or thrill over access - treatment: angiographic clot removal or angioplasty within 24 hours; direct injection of alteplase can be considered for thrombosis

Vascular Access Infections - 2 - 5% of AV fistulas, 10% of grafts - etiology: Staphylococcus aureus (most common), Gram-negative bacteria - signs/symptoms: hypotension, fever, leukocytosis - may not have pain, erythema, swelling, or discharge from access site - after 6 months, approximately 1/2 of patients with dialysis catheter develop bacteremia - diagnosis: peripheral and catheter blood cultures drawn simultaneously -> catheter is confirmed source if colony count is 4 times higher in catheter culture than peripheral culture - treatment: vancomycin IV (drug of choice) +/- gentamicin (if Gram-negative organisms suspected); consider access removal if fever for > 2 - 3 days

Hemorrhage - rare - causes: aneurysms, anastosmosis rupture, overanticoagulation

Management of Hemorrhage 1. manual pressure to puncture sites for 5 - 10 min and observe for 1 - 2 hours if ceased 2. apply pressure for 10 min using absorbable gelatin sponges soaked in reconstituted thrombin or chemical thrombotic (e.g., transexamic acid) 3. protamine 0.01 mg per unit of heparin dispensed during dialysis - if dose is unknown, protamine 10 - 20 mg is sufficient to reverse typical dose of heparin (usually 1000 to 2000 U) 4. desmopressin acetate 0.3 mcg/kg IV can be used as adjunct in consultation with nephrologist or vascular surgeon 5. consider placing figure-8 suture 6. tourniquet proximal to vascular access while awaiting urgent vascular surgery consultation

Vascular Access Aneurysms - caused by repeated punctures - usually asymptomatic, possibly occasional pain or impingement neuropathy - rarely rupture

Vascular Access Pseudoaneurysms - from subcutaneous extravasation of blood from puncture sites - signs: bleeding, infection at access site - diagnosis: arterial Dopper ultrasound studies - treatment: surgery

Vascular Insufficiency - usually occurs in extremity distal to vascular access - due to shunting of arterial blood to venous side of access - "steal syndrome" - signs/symptoms: exercise pain, nonhealing ulcers, cool/pulseless digits - diagnosis: Doppler ultrasound or angiography - treatment: surgery

High-output Heart Failure - occurs when >20% of cardiac output is diverted through access - signs/symptoms: Branham sign (drop in heart rate after temporary access occlusion) - diagnosis: Doppler ultrasound to measure flow rate - treatment: surgical banding of access

Resources Tintinalli's Emergency Medicine, 8th Edition