The following is a tutorial on basic airway pressure release ventilation (APRV) setup and troubleshooting. Over the next few days, I’ll update with video showing how to setup both the VELA and Draeger ventilators.
There are multiple theoretical advantages of APRV over conventional ventilator strategies (see review articles below) however some of the benefits specific to the COVID-19 patient population is the prevention of derecruitment and encouragement of spontaneous breathing with consequent decreased need for deep analgosedation. While APRV can be set up directly in the newly intubated patient, it is perhaps easier to transition from more a more familiar conventional modality such as ACVC.
- After RSI, place pt on ACVC utilizing low tidal ventilation strategy per ARDSnet protocol. Initiate analgesia and sedation strategy.
- Once PEEP has been titrated per ARDSnet PEEP/O2 tables, paralysis has worn off and the patient is spontaneously breathing, consider transition to APRV
- Set Pressure high (Phigh). While still on ACVC, perform inspiratory hold and measure Plateau Pressure. The plateau pressure will be your starting Phigh in APRV. Values are typically between 20-35 cmH20
- Set Time high (Thigh) between 4-6s. Longer Thigh will increase oxygenation
- Set Pressure low (Plow) to 0* (see discussion below)
- Set Time low (Tlow). APRV relies on autopeep(iPEEP) to prevent derecruitment of alveoli, therefore your release time or Tlow is critical. The longer the Tlow, the lower the iPEEP and the greater the likelihood of alveolar collapse. In order to adjust Tlow we need to observe the patients expiratory flow waveform on the ventilator, targeting >50% T-PEFR (see below). This will typically be between 0.2-0.8s in restrictive lung disease and 0.8-1.5s in obstructive lung disease. The shorter the Tlow, the greater the mean airway pressure which will generally increase oxygenation.
- Spontaneous Breathing is crucial in APRV. Add pressure support of 5 (on VELA) or automatic tube compensation (on Draeger or Puritan Bennett) to help augment the patients own respiratory efforts which will assist in ventilation.
- Troubleshooting Hypoxemia. Overall, to improve oxygenation we need to increase mean airway pressure and/or recruit atelectatic alveoli. Assuming your FiO2 is already 100%, consider the following steps:
- shorten Tlow up to T-PEFR 75%
- increase Phigh and Thigh simultaneously. Phigh >35 may be required in the morbidly obese
- Troubleshooting Hypercapnia. Mild hypercapnia without severe acidemia can be tolerated in these patients. Optimizing ventilation should be performed cautiously in a way that does not compromise oxygenation.
- Lighten sedation to encourage spontaneous ventilation.
- Increase Phigh and Thigh simultaneously.
- Lengthen Tlow by 0.05-1s increments up to 50% T-PEFR. (while this will increase tidal volumes during release, this will also decrease mean airway pressure and likely worsen oxygenation)
- Increase Phigh while decreasing Thigh (not recommended). while this will increase minute ventilation, it will also decrease mean airway pressure and worsen oxygenation.
Below is the table from the Habashi review article which details setup as well as troubleshooting. I highly encourage everyone to read the review prior to your first attempts using APRV.
T-PEFR – ventilator flow waveform (resusreview.com)
Great Review article by Nader Habashi on APRV
APRV by Habashi
Alternative approach to Tlow/Plow settings*. (skip this part until comfortable with Habashi method) An alternative strategy for APRV has been proposed by Zhou et al. The Zhou method is notably different in their approach to determining Tlow which is determined by starting with a Tlow of ~1s, multiplied by the time constant (resistance*compliance) and then targeting T-PEFR >50%. In addition, Zhou also utilizes a starting Plow of 5 cmH20, while Habashi recommends Plow of 0. Many pulmonary physiologists criticize APRV because it relies on autoPEEP(iPEEP) to prevent derecruitment of alveoli. iPEEP does not uniformly affect the lung. iPEEP will recruit healthy alveoli with increased compliance preferentially over diseased low compliant alveoli which could potentially worsen atelectatrauma. With that in mind, per the starling resistor model extrinsic PEEP and iPEEP are not additive unless extrinsic PEEP exceeds iPEEP. Adding additional extrinsic PEEP with the ventilator (eg. Plow 5 cmH20) would likely not affect healthy alveoli already stented by iPEEP but may prevent the full derecruitment of diseased/low compliance/stiff alveoli. Adding Plow may prolong the release time necessary to reach T-PEFR 50-75%.
Below is Zhou’s alternative APRV initiation and titration strategy taken from their study protocol. Of note, Zhou utilized Puritan Bennett ventilators (like our 840s) which likely explains some of the differences in initiation/setup. While 840s can be used to provide APRV, the setup is less straight forward than on the VELAs and Draegers.
More recent review article summarizing trials as well as reviewing alternative strategy by Zhou.
another site with tutorial based on Habashi APRV strategy
Any questions about setting this up? Grab me while I’m working clinically and I’ll walk you through it or call me anytime with questions 917-749-1004.
Some suggestions in terms of workflow for airway management.
The following in an ongoing collaboration with Nick Caputo at Lincoln as we are attempting to develop a unified approach between sites to allow us all to learn from one another’s success and mistakes. Check back frequently for updates as our supplies and what we know about the disease changes.
Ventilator shortage. The hospital is facing a significant ventilator shortage. In addition to our 7 VELA ventilators, there are 3 transport ventilators in radiology and 11 anesthesia machines in the OR. 1 transport ventilator should remain in radiology for use with patients requiring CT. If OR ventilators are required, contact anesthesia for assistance in initial setup and questions.
We have 50 emergency transport ventilators with extremely limited capabilities. Specifically, they are asynchronous and provide a maximum PEEP of 5cmH20 which makes them of limited value in the setting of severe ARDS. The devices are a bit tricky to use, so look over the following visual guide and watch the video beforehand. There is a ventilator in the admin office connected to a test lung and O2 cannister to practice with.
Instructions_VORTRAN Automatic Resuscitator VAR MODEL RC
Dual Ventilation Strategy
Dual ventilation strategy should only be considered as a last resort. If attempting to do so, the following protocol may improve safety.
Non-invasive ventilation. In light of impending ventilator shortage, it is prudent that we avoid any unnecessary intubation. If clinical history suggests that there may be a reversible component of failure (eg. CHF, asthma) then it may be reasonable to attempt at short trial of NIV. A few guidelines for NIV:
-NIV should only be attempted with our closed circuit ventilators with a non-vented facemask. The single limb dedicated BiPAP machines have a vent in the mask which will aerosolize droplets into the room when the patient exhales
GUIDANCE OF ADMINISTRATION OF ALBUTEROL TO VENTILATED BIPAP EDIT
-Attach HEPA filter at the mask prior to Y connection of the tubing
-Place patient in isolation tent
-Ensure tight mask fit prior to initiation of ventilation
-If albuterol administration required, administer via MDI adapter or aerogen nebulizer as pictured below
Any questions don’t hesitate to contact me anytime. text/call 917-749-1004.
To minimize potential aerosolization during administration of albuterol we are trying to utilize MDIs primarily. For intubated patients or those requiring NIV you can administer albuterol MDIs via inline adapter. Alternatively, the aerogen device also minimizes leak compared to the typical acorn nebulizers but it’s effect on droplet dispersal is unknown.
GUIDANCE OF ADMINISTRATION OF ALBUTEROL TO VENTILATED BIPAP EDIT
in-line MDI adapters and aerogen nebulizers are located on the respiratory cart behind the cardiac workstation, located on the same shelf as the VL blades.
Thank to Suzi Bentley for putting together the visual guide.
Below are the updated AWS guidelines for the EHC emergency department. Note that chlordiazepoxide/librium is favored in all patients who are able to take oral medications and who are not severely agitated (RASS ≥3). The goal of therapy is a calm to drowsy patient (RASS 0 to -1) regardless of HR/BP. If a patient remains tachycardic despite adequate sedation, strongly consider concurrent or alternative pathology, eg. sepsis.
EHC AWS algorithm 11-28
In addition, use of the non-benzodiazepine (BZD) adjuncts such as dexmedetomidine/precedex is not advised unless the patient is refractory to BZD and barbiturate therapy. The refractory AWS pathway (pg2) outlines a suggested strategy for those patients in whom adequate control cannot be obtained despite diazepam 200mg and phenobarbital 390mg. In these patients the overall goal is to avoid intubation unless absolutely necessary. The suggested non-BZD adjunct in this scenario is ketamine, which is more strongly supported by evidence.
The goal of management in AWS is to determine the dosage of benzodiazepine that is required to control a patient (calm/alert to slightly drowsy or RASS 0 to -1) for at least 1hr from last administration of medication.
In addition to admission to a unit capable of appropriate level of care, evaluate patients for co-morbid conditions such as trauma, sepsis, pancreatitis, DKA/AKA, etc. Strongly consider the supplementation of multivitamin/thiamine/folate to patients at risk for malnutrition.
These guidelines were adopted from Bellevue’s AWS protocol and updated with the assistance of our EHC/MSSM toxicologists Alex Manini, Rachel Shively and Beth Ginsburg. Any questions or concerns please feel free to contact me at firstname.lastname@example.org
Below are updated resources for the management of sexual assault survivors. Permanent links to the documents can also be found under the guidelines tab.
Sexual assault checklist
HIV PEP follow up information
HIV PEP Follow-up Information
HIV PEP starter pack information
HIV PEP Starter Pack Information
Tip sheet for ordering HIV PEP
Tip Sheet for Ordering HIV PEP
SART bill of rights
SART BIll of Rights (1)
A few people were asking for a quick reference regarding age related proBNP cutoffs.
Embedded below are links to both the PRIDE and ICON-RELOADED trials which investigated proBNP cutoffs in the emergency department.
The optimal age-independent cutoff for ruling out acute heart failure is <300 pg/ml
The optimal age-adjusted cutoffs for ruling in acute heart failure are:
<50 years old – 450 pg/ml
50-75 years old – 900 pg/ml
>75 years old – 1800 pg/ml
Given the current weather it seems appropriate to post some guidance for patients suffering significant cold exposure. Below are concise guidelines from OSU medical center and the Wilderness Medical Society (pre-hospital). Both have useful information in regards to management along the spectrum of exposure.
OSU Management of Accidental Hypothermia
At this time we are referring all all ECMO transfers to Montefiore’s Cardiothoracic Surgical ICU. Although most ECPR cases are not typically candidates for on-site cannulation and transfer, in some rare hypothermic cases (eg. young patient, short downtime) there may be an exception.
To initiate possible transfer first call 718-920-ECMO and provide the following: Patient name, Diagnosis and Location. The transfer center will connect you with a CT surgeon with whom you can discuss the case and decide whether the patient is a candidate for potential transfer.
If ECMO is deemed appropriate, next call the AOD in order to initiate the emergency credentialing process for the surgeon.
EXCLUSIONS to CPR
Appropriate situations in which to terminate efforts for performing CPR in hypothermic patients with cardiac arrest:
- Body is frozen solid (cannot perform chest compressions, no chest recoil)
- Obvious non-survivable injury (eg. Decapitation, truncal transection, incineration/decomposition of whole body)
- Airway obstruction (snow/ice) with downtime greater than 1 hour (more for avalanche victims than urban recoveries)
Thoracic lavage should be reserved only for pulseless patients. A few variations of the procedure are possible including single and dual tube methods. A good review can be found here THORACIC LAVAGE
Thank you to Neil Dubey and Mark Andreae for their help with this post.
Changes, Updates, Important Information
- When you are on a cardiac room shift or trauma shift, please arrive a few minute early to check that your supplies are well stocked and airway boxes are ready to go. When you use supplies and airway boxes, don’t forget to reset.
- If a patient leaves during evaluation (this means “provider in” is clicked, orders of any kind are placed, any note is written by a midlevel or attending provider) please indicate “Left During Evaluation” and NOT “Eloped” or “LWBS…”in the Dispo section of the chart.
- Current drug shortages: kayexelate, epipen
- Psychiatry consults: (Do not use the paging operator, amion is not yet updated)
- Mon-Fri 8a-5p call 6-6934 (cordless); OR as backup page 40524 for the consult attending
- Mon-Fri 5p-8a, weekends, holidays page 15094 – consult resident; OR as backup call the Bell attending 6-4750 (cordless)
- Patients from Rikers Island who are discharged back to Rikers should have printed copies of their:
- (1) H&P and consultant notes (i.e. psych notes);
- (2) “ED to PCP summary” (i.e. results of diagnostic studies); and
- (3) AVS (i.e. clear discharge instructions with medication recommendations)
- (4) placed in a sealed envelope and handed to the Corrections Officer, NOT the patient
- Please provide “Procedural Sedation” and “Stroke and TIA Prevention” discharge instructions to patients as appropriate.
- Please take the time to schedule appropriate follow up appointments for patients. This is especially important for our Elmhurst population with generally poor health literacy.
- All patients diagnosed and treated or suspected and treated for a sexually transmitted illness (STI) MUST be followed up in the Sexual Health Clinic (SHC). Discharge clerks can schedule appoints as early as the next business day. This includes women treated for possible PID, men with confirmed or suspected GC/Chlamydia and anyone with suspected/confirmed syphilis.
- Newly diagnosed HIV positive patients are to be referred to the ID clinic NOT to the SHC. There are resources in the SHC for face-to-face patient counseling, HIV pre-exposure prophylaxis (PreP) medication and partner surveillance. They’ll also refer female patients to the gynecologic clinic, if necessary, after they’ve met with these patients.
- Do NOT overbook Proctology Clinic. If there is no availability, in the timeframe you need, then send the patient to the General Surgery clinic.
- Patients with suspected ectopic pregnancy should follow up in GYN Surgery clinic.
- Transfer formsMUST be completed on all transfer patients regardless of the service requesting the transfer.You’ll find the Transfer Form after you’ve selected “Transfer to Another Facility” on the Disposition Tab >> TRANSFER/EMTALA Forms >> complete the form – especially the ACCEPTING HOSPITALand ACCEPTING ATTENDING PHYSICIAN (not resident)! Then save, print, and give the form to the sending RN.
- For radiology studies select an indication AND include a brief comment on the reason for exam.
- When ordering PLAIN X-ray imaging place a patient transport request in EPIC. On the main tracking board select the patient, click on “patient transport”, select “EL Radiology” as the location and priority “high”.
- If you change the admitting service or level of care, you need to (1) change the admission service order in EPIC AND (2) also call Admitting
- The ED attending makes the final admission decision, please check with them before admitting.
- Any patient with a traumatic injury MUST be admitted to a surgical service. If they need telemetry or have complex medical diagnoses, the SICU fellow or attending should be consulted for SICU or surgical step down bed assignment.
- Please use the “quick lists” to order medications. These are set up to have appropriate dosing, administration and titration instructions for the ED. In addition the IV push doses of relevant medications have now been added to this list.
- Click the provider in button and indicate the time you first saw the patient for every patient you see (if it has not already been done).
- Uses the physical exam checkboxes in EPIC to document guaiac results.
- Vaginal ultrasound probe cleaning (Trophon)/use monitoring: Name-sticker placed in the black folderwhen we use the pelvic ultrasound probe. This must be done every time by either the ED provider, chaperoning PCA, or the Gyn consultant.
- Ultrasounds: Please clean the ultrasounds and plug them in after use. Please order, save images, and read all ultrasounds performed in the ED.
- We have Naloxone kits available for free distribution to at risk patients. Most of the attending physicians have completed the training to dispense the kits. Please consider this for your patients and ask the attendings when appropriate.
- Apply a patient label or baxter label to the EMS notification sheet when applicable. Continue to place these sheets in the bin by the phones.
- Continue to save all ultrasounds, especially all FAST exams done during trauma to Q-path. These should be linked to the patient in Q-path, interpreted by the resident and signed by the attending.
- Please help us meet sepsis treatment criteria. We are missing sepsis marker primarily because of these four things:
- Blood cultures not marked as collected prior to antibiotic being marked as given – REMIND YOUR RN;
- Time to fluid and antibiotic administration – We have 3 hours from arrival;
- Failure to repeat elevated lactate by 6 hours;
- Failure to write a sepsis reassessment note after fluids are given.
Colleen and Moira
FULL BLOCK 4 UPDATE Elmhurst Updates SEPTEMBER 2018
The most recent EHC Traumatic spine and brain injury protocols. Both can be found permanently linked under the cardiac/trauma tab
We are now stocking a few new items in the trauma room wall racks near bed 3 behind the nursing station.
We have both the T-POD as well as pean clamps for sheet binding if preferred. For those unfamiliar with T-POD application, here is a video tutorial
for review. In addition I have a trainer and will happy to inservice anyone interested.
Tourniquets are also now available. Pretty self explanatory but Here
are a couple of videos regarding application of tourniquets. I’ve also attached a scan of the product insert with instructions.
QuiKClot Combat Gauze
QuikClot is a kaolin impregnated gauze pad that allows for topical hemostasis by activating factor VII. It is clay based and unlike prior formulations of quikclot does not result in exothermic reaction and has not been found to be associated w/ allergic reaction. It can be used in any situation in which you encounter difficult to control bleeding, eg. proximal injuries you are unable to tourniquet, avulsion injuries, oozing from vascular access sites including shunts, oozing from scalp wounds, etc. If hemorrhage control is unsuccessful after application, leave the initial pad in place and apply another to minimize disrupting existing clot. The gauze can be left in place for 24 hours but once dried should be soaked with saline prior to removal.
The following tutorial is courtesy of Dr. Colleen Smith.
Transvenous pacing trays and pacing generator are located in the green cabinets above the sink in the Cardiac Room.
- Transvenous Pacing Electrode Tray containing:
- TVP catheter
- Percutaneous sheath introducer w/ syringe/guidewire/dilator
- Sterile sleeve
- 2 adapter pins
- Alligator clamp
- 3ml syringe that stops at 1.5ml
- Pacing generator box with extension connecting cable (attached to the box)
- Central line bundle with sterile patient drape, and sterile gown
- Sterile gloves
- Ultrasound machine with linear probe and sterile ultrasound probe cover,
Set up pacing generator box
- Turn generator box on by pressing the on button. Insert a new battery if necessary.
- Set the mode or sensitivity to demand or asynchronous pacing
- Set rate control above the native rate or the transcutaneous pacing rate usually around 80bpm
- Turn V (ventricular) output control to the max mAmps (usually 20-25mAmps)
Placement (Under sterile field with large patient drape, sterile gown, gloves, etc.)
- Place sheath introducer as you would place a Cordis type of central line, confirm venous placement with ultrasound and suture in place.Preferred site: Right internal jugular. Secondary site: Left subclavian (Try to save this for permanent pacemaker if possible.)
- Connect the pacing extension cable(s) to the pacing generator box.
- Connect the proximal lead of the pacing catheter to the positive (+) port of the pacing extension cables (or generator box
- If using ECG to guide placement: Connect the distal or negative (-) lead of the pacing catheter to the V2 attachment of the monitor or ECG machine using the alligator clip in the TVP catheter kit. This lead will now display an ECG waveform based on input sensed by TVP catheter as you place it. *See image below
- Thread the STERILE SLEEVE over the TVP catheter PRIOR to inserting the catheter into the introducer. (Keep the sleeve collapsed and pull it far back.) The TVP catheter should go through the blue end of the sleeve first so that the green end of the sleeve can connect with the sheath introducer.
- Place the TVP catheter – oriented so that it curves toward the heart.
- If using the balloon (optional):
- Only use the syringe that comes in the kit.
- Check the balloon for leaks by inflating it prior to inserting the catheter.
- Inflate the balloon when you have inserted to about 20cm (2 slender dashes on the catheter) and lock it in that position prior to advancing the catheter
- ALWAYS deflate the balloon and lock it down prior to retracting the TVP catheter.
- Correct placement should occur between 30 and 40cm, consider measuring with TVP catheter over the patient’s chest prior to placing.
- If you have gone too far, DEFLATE the balloon and retract the TVP catheter back to the 5-10cm mark, reinflate the balloon (if using) and reinsert the TVP catheter.
- Confirm capture with:
- ECG waveform attached to negative lead of TVP wire (injury pattern, see attached images)
- Capture on monitor (LBBB with ST elevation at set rate)
- Cardiac ultrasound (wire visible in right ventricle)
- When you have capture. Deflate the balloon and lock it closed. Insert the TVP catheter another 5-10mm.
- Secure the green end of the sterile sleeve to the introducer. (This should hold the TVP catheter in place). Pull sleeve open fully and secure the blue end of the sterile sleeve to the TVP catheter. (This ensures continued sterility of the portion of the TVP wire within the sterile sleeve so that it can be adjusted.)
- Apply sterile dressing to the introducer insertion site
Procedure Completion (You can now break sterile field)
- Connect the distal lead of the TVP catheter to the negative (-) input of the generator box (if not already done.)
- Remove the syringe for the balloon and tape it to the wire.
- Adjust mAmps by decreasing the ventricular mAmps until you loose capture and then go up x2 (or 20% higher than your lowest capture number)
- Obtain a CXR to further confirm placement and location, check for pneumo- or hemothorax.
- Obtain a 12 lead ECG to confirm pacing spikes and widened QRS for every beat.
- Same as any central line: pneumothorax, improper placement, arterial placement, etc.
- Valve rupture or tear. Caused by retracting the TVP catheter with inflated balloon. Detect by new murmur, acute heart failure, echo.
- Perforation of the LV causing tamponade. Detect by sudden hypotension with narrow pulse pressure, pericardial effusion on echo. DO NOT REMOVE TVP Catheter.
- Pulmonary artery rupture or tear. Caused by inflating the balloon in the pulmonary artery. Results in tamponade physiology.
- Septal wall perforation. Caused by pushing the TVP catheter through the septum. Results in left to right shunt physiology, acute right heart failure, hypoxia