NG Tube for SBO

Is a nasogastric (NG) tube really needed for management of small bowel obstruction (SBO)? NG tube placement is one of my least favorite ED procedures. I therefore find myself hesitating every time surgery requests one, but what is the evidence behind it?

Surprisingly, there is little data and no randomized control trials on the use of NG tubes in SBO. A chart review in 2013 looked at 290 patients admitted with SBO. 20% of those 290 patients had a NG tube placed. They found that ⅔ of these patients were managed non-operatively, irrespective of NG tube placement. In addition, decompression with an NG tube was not found to be associated with decreased bowel ischemia or need for surgery. Use of an NG tube was actually found to be associated with worse outcomes, such as increased length of hospital stay, higher complication rate, and longer time to resolution.

Part of the reason that I dislike this procedure is the apparent discomfort we cause when placing them. Patients routinely rate it as one of the most painful procedures performed in the ED. We attempt to decrease pain with anesthetics, even though many ED physicians do not believe them to be effective. A RCT was done assessing the use of surgical lubricant versus topical lidocaine and phenylephrine for the nose with tetracaine and benzocaine spray for the throat. Patients reported a significant decrease in discomfort when providers used vasoconstrictors and topical anesthetics compared to surgical lubricant. 

However, there are some cases where NG tubes may be indicated. Patients who are vomiting after antiemetics or have a significantly distended stomach may benefit. Rather than placing them on all patients diagnosed with an SBO, we should select patients for this procedure based on their symptoms.

Thanks for reading!

Ariella 

Resources:

Fonseca AL, Schuster KM, Maung AA, Kaplan LJ, Davis KA. Routine nasogastric decompression in small bowel obstruction: is it really necessary? Am Surg. 2013 Apr;79(4):422-8. PMID: 23574854

Paradis M. Towards evidence-based emergency medicine: Best BETs from the Manchester Royal Infirmary. BET 1: Is routine nasogastric decompression indicated in small bowel occlusion? Emerg Med J. 2014 Mar;31(3):248-9. doi: 10.1136/emermed-2014-203617.1. PMID: 24532357

Singer AJ, Konia N. Comparison of topical anesthetics and vasoconstrictors vs lubricants prior to nasogastric intubation: a randomized, controlled trial. Acad Emerg Med. 1999 Mar;6(3):184-90. doi: 10.1111/j.1553-2712.1999.tb00153.x. PMID: 10192668

Witting MD. "You wanna do what?!" Modern indications for nasogastric intubation. J Emerg Med. 2007 Jul;33(1):61-4. doi: 10.1016/j.jemermed.2007.02.017. Epub 2007 May 30. PMID: 17630077

Temporary Wayne Catheter Replacement Kits

I wanted to make you aware of the new *temporary* replacement pigtail kits that we have available right now. We have ordered the normal Wayne catheter replacements, but they will take a little more time to come. You can find the pigtail kits in the cabinets between Resus 51/52. I've attached the picture of the packet, and a quick video tutorial (https://tinyurl.com/578wnbve) that shows you how to use it.

Contents of the new kits:

- short needle
- guide wire
- 3-way stopcock
- Heimlich valve
- pigtail catheter
- dilator

This is a very basic kit, so I recommend that you grab the following supplies that are not included in the packet.

- 10cc syringe to attach to the needle
- Lidocaine supplies (lido, syringe, blunt needle, subQ needle)
- Chloraprep
- Sterile supplies: gown, sterile gloves, drape
- Gauze
- 11 blade scalpel
- Suture material, needle driver
- Occlusive dressing materials

Please note - there's no separate trocar! The kit requires you to use the guide wire as the trocar... so make sure you dilate well. If your patient has a higher BMI, talk to your attending about whether or not this is the appropriate kit for them.

Central Venous Access: Arterial Complications

Central lines are something we routinely do but can and do lead to complications. Complications include pneumothorax, dysrhythmias, guidewire loss, and of course arterial cannulation. We will focus mostly on talking about arterial cannulation and arterial dilation/insertion of a catheter. Arterial injury occurs in less than 1% of catheter placements, but arterial puncture occurs in 4.2–9.3% of line placements. Most of the time it is often easily recognized secondary to pulsatile flow, the artery is not dilated, and pressure is held with no complications. Hematoma formation has been reported in up to 4.7% of all catheter placements. Hematoma formation is often not life-threatening.

Complications from arterial puncture, and especially arterial dilation & catheter insertion include AV fistula, arterial thrombosis & subsequent stroke, arterial pseudoaneurysm, & arterial dissection. Immediate removal of an accidental arterial catheter can result in uncontrolled hemorrhage so the catheter should be left in place for removal by interventional radiology or vascular surgery (direct suture repair, percutaneous closure device, stent-graft insertion). Studies have demonstrated that leaving the arterial catheter in place with prompt repair carries less morbidity and mortality than catheter removal with pressure. 

Discerning if you are in the artery or vein 

1. Ultrasound can be used to confirm appropriate guidewire placement in the venous system prior to dilation

2. Venous pressure waveform on CVP monitor (applies more for ICU)

3. Watch for pulsatile flow, but recognition may be difficult in a hypotensive patient, which are a significant portion of patients who are getting central access

4. Send off blood gas and decide if it is a VBG or ABG (but VBG may resemble ABG in a hyperoxic patient on high FiO2) 

5. Confirmation using angiocath in the central line kit in conjunction with the extension tubing and evaluating the column of blood in the extension tube. Dr. Strayer has a complete description here. https://emupdates.com/catheter-in-artery-vs-vein/

6. CxR showing catheter going towards RA (venous) vs LV (arterial). However, with this method, confirmation is achieved only after dilation. 

If inadvertent arterial insertion fails to be recognized, further complications can arise from infusion of vasopressors into arterial circulation, such as ischemic stroke. 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4613416/

https://www.reliasmedia.com/articles/131944-complications-of-tubes-and-lines-part-i

https://emupdates.com/catheter-in-artery-vs-vein/