Contrast: PO or no to PO, that is the question.

In the past, we have always used PO and IV contrast for CT abdomen/pelvis scans in studies to "rule out" SBOs, but recently we have been told by the Chief of Surgery Dr. Nicastro that PO contrast is not necessary to rule out SBOs however some surgical residents and attendings may still ask for PO contrast. Here are some learning points so that you can advocate for your patient and discuss with the surgical team about why we may not need PO contrast in your next SBO patient!

Historical Use of PO Contrast in SBO Evaluation

• Early CT protocols included PO and IV contrast for abdominal imaging to better outline the bowel lumen and identify transition points. 

• PO contrast was initially thought to improve diagnostic accuracy by helping to distinguish dilated bowel from collapsed bowel and aiding in localizing the obstruction. (Balthazar 1997)

Advancements in CT Technology

• Multidetector CT scanners introduced in the 2000s drastically improved resolution, allowing clear visualization of bowel loops, wall enhancement, and obstruction points without the need for PO contrast.

• IV contrast became the primary agent for assessing bowel wall integrity, ischemia, and complications, which are critical components in SBO management. (Jaffe 2006; Taylor 2013)

• Evidence showed high diagnostic accuracy (90–95%) with IV contrast alone, questioning the need for PO agents in most cases. (Gore 2000; American College of Radiology 2020)

Other Contraindications for PO Contrast Use

• PO contrast often delays imaging as patients may need 1–2 hours to ingest the contrast and allow it to move through their digestive tract, delaying care. 

• Patients with high-grade SBO may be unable to tolerate oral intake, increasing the risk of vomiting and aspiration. (Maglinte 2013)

• Excessive intraluminal contrast can also obscure bowel wall features, including mural enhancement or signs of ischemia. (Paulson 2005)

However, even though PO contrast may not be useful in suspected high-grade SBOs, it still has its uses if other diagnoses are suspected:

Indications for PO Contrast in CT abdomen/pelvis

• PO contrast can help delineate the transition point in indeterminate, low-grade, or partial obstructions.

• Water-soluble oral contrast (e.g., Gastrografin) may help identify extraluminal leak sites after bowel surgery. 

• PO contrast can help visualize and evaluate known or suspected enteric fistulas between bowel segments or between bowel and other structures (e.g., bladder, skin). 

• Oral contrast can help assess strictures, skip lesions, or fistulas—especially in combination with enterography techniques to evaluate inflammatory bowel disease (IBD). 

• CT Enterography or CT Enteroclysis requires neutral or low-density PO contrast to assess small bowel mucosa and pathology (e.g., Crohn’s disease, obscure GI bleeding). 

• PO contrast may help clarify mass relationships to bowel loops or identify lumen involvement in preoperative planning for known mass lesions. 

Takeaways

• IV contrast-enhanced CT is now the standard for initial SBO evaluation, with PO contrast reserved for select, stable cases of suspected partial obstruction.

• There may still be an indication for PO contrast based on the patient’s clinical stability, level of obstruction, and specific diagnostic question.

References:

Balthazar EJ, et al. “CT of SBO: value in establishing diagnosis and determining degree and cause.” AJR Am J Roentgenol. 1994, 1997.

Gore RM, et al. “Bowel obstruction.” Radiol Clin North Am. 2000.

Jaffe TA, et al. “CT of small-bowel obstruction: how reliable is diagnosis and extent?” AJR Am J Roentgenol. 2006.

Maglinte DDT, et al. “Radiologic diagnosis of small-bowel obstruction: current role and future trends.” Radiol Clin North Am. 2013.

Paulson EK, et al. “Small-bowel obstruction: the role of CT evaluation and contrast agents.” Radiology. 2005.

Taylor GA, et al. “ACR Appropriateness Criteria® on suspected small-bowel obstruction.” J Am Coll Radiol. 2013.

American College of Radiology. “ACR Appropriateness Criteria® Suspected Small-Bowel Obstruction.” 2020.

Hyperkalemia

40 y/o male with PMHx of metastatic colon cancer s/p chemo, resection with ostomy, cirrhosis due to liver mets, recent admission for hyponatremia and recurrent ascites who presents to the ED North side resus as a transfer from Bay Ridge for hypotension, requiring critical care. Patient did not have labs drawn at Bay ridge but EKG was done:

Low voltage, slight sinus tachycardia at a rate of 101.

Upon arrival on North side the patient had labs drawn:

After the ED team got the lab results, the nurse came over and stated the patient's cardiac monitor looks like QRS was widened, so they got the patient's EKG:

sinus tachycardia at 100bpm, widened QRS

And ordered the patient 2g Calcium Gluconate and Insulin Lispro 5u, which in our order set looks like this:

The nurse drew up the medications and brought it bedside, but before administering the medications, the patient's family looked concerned as the patient just became unresponsive.

Nurse checked for a pulse, the patient did not have a pulse, CPR started.

ROSC was achieved within 10 minutes, patient was intubated, placed on pressors for hypotension.

Patient's repeat labs revealed only slight hyperkalemia, but profoundly acidotic, did not have a repeat arrest while in the Emergency Department, but expired during his course.

Hyperkalemia is something that we see very often in the Emergency Department. We have an order set to help manage it, but there isn't an official hyperkalemia management algorithm.

Our order set is based off literature from the last 20+ years, but here is a review of hyperkalemia management and ongoing controversies

Hyperkalemia Treatment

• Membrane Stabilization (Rafique 2021, Weisberg 2008)

  • For ECG changes or K⁺ > 6.5–7.0 mEq/L

  • IV calcium

    • Calcium gluconate (preferred) 

    • Calcium chloride (more potent but vesicant)

  • 10 mL of 10% solution IV over 2–5 minutes

  • Repeat every 5–10 minutes if ECG changes persist

  • Onset: <5 minutes; Duration: 30–60 minutes

  • Safe even in digoxin toxicity per updated literature (contraindication is outdated)

• Intracellular Redistribution (Moussavi 2019, Keeney 2019, Ibarra 2024)

  • Insulin + Glucose - Shifts potassium into cells via Na⁺/K⁺ ATPase activation

    • 5 units or 0.1u/kg of regular insulin + prolonged D10 infusion (250 mL over 2 hours) reduces rebound hypoglycemia

    • Onset: ~15-30 minutes; lowers K⁺ by 0.6-1.2 mEq/L

  • Beta-2 Agonist (Albuterol)

    • Nebulized 10–20 mg

    • Onset: ~30 minutes; lowers K⁺ by ~0.5 mEq/L

    • Additive to insulin; useful when IV access is delayed

    • Less effective in patients on beta-blockers

• Elimination of Potassium

  • Hemodialysis - most rapid and definitive method indicated in:

    • Refractory hyperkalemia

    • Anuric or oliguric renal failure

    • Cardiac arrest due to hyperkalemia

  • Loop Diuretics

    • Furosemide if volume status and renal function permit

  • GI Binders:

    • Sodium polystyrene sulfonate (SPS / Kayexalate

      • Onset 2-6 hrs; low efficacy; risk of colonic necrosis, especially when combined with sorbitol

    • Patiromer & Sodium Zirconium Cyclosilicate (ZS-9)

      • Safer alternatives with better GI tolerability but not for emergent use due to slow onset

Controversies in Hyperkalemia Management

• Reliability of ECG (Meyers 2017, Weisberg 2008)

  • ECG findings are neither sensitive nor specific

  • Many patients with severe hyperkalemia have normal ECGs

  • Others progress directly to VF/asystole with minimal ECG changes

  • Normal ECGs cannot rule out severe hyperkalemia 

• Sodium Polystyrene Sulfonate (SPS) Use (Sterns 2010, Parks 2019, Gupta 2021)

  • Poor efficacy in acute setting

  • Associated with intestinal necrosis, especially with sorbitol

  • Should be avoided in ED settings; consider alternatives 

• Insulin Dosing and Dextrose (Moussavi 2019, Keeney 2019, Ibarra 2024)

  • Previously thought that 10u regular insulin is required

    • 5u or weight-based (0.1u/kg) is equally effective

    • Reduces risk of hypoglycemia, especially in ESRD, low body weight, or nondiabetics 

  • D50 bolus alone may not match insulin duration

    • D10 infusion lowers risk of delayed hypoglycemia and is now preferred 

• Pseudo- and Spurious Hyperkalemia

  • Hemolysis, high WBC/platelet count, poor draw technique can falsely elevate K⁺

  • If patient has normal GFR and ECG, may not require treatment even if K⁺ > 5.5–6.0

• Bicarbonate Use (Weisberg 2008, Rafique 2021, Long 2018, Gupta 2021)

  • Controversial benefit unless pH <7.2

  • It helps correct acidemia and facilitates K shifts into cells via H⁺/K⁺ exchange 

  • May augment the effect of insulin and beta-agonists when used in acidemic patients, although it is rarely sufficient as monotherapy
    
    
    
    
    
    

  • Bicarbonate is specifically indicated in cases of TCA overdose requiring alkalinization, which may coincide with hyperkalemia
    
    
    
    
    
    

  • Minimal or no effect on serum potassium in patients with normal acid-base status

  • Bicarbonate infusion is slow-acting, taking hours to shift potassium compared to minutes with insulin or albuterol

  • Large-volume sodium bicarbonate infusions may lead to hypernatremia, volume overload, or metabolic alkalosis, particularly in patients with renal or heart failure

  • Alkalosis induced by bicarbonate can lower ionized calcium, potentially worsening arrhythmogenic risk in some settings

  • Sodium bicarbonate alone is not shown to reverse ECG changes caused by hyperkalemia and is not a substitute for calcium in membrane stabilization

Takeaways:

• Give Calcium gluconate every 5-10 minutes until ECG changes resolve

• Even if Potassium is not >6.0, patient may still have severe hyperkalemia

• If there are ECG changes and suspected hyperkalemia, treat aggressively but a "normal" ECG alone cannot "rule out" hyperkalemia

• Sodium Bicarbonate may only be effective in patients with acidosis to help augment other agents in reducing potassium levels, but otherwise not recommended

Broselow Cart

Level 1 pediatric trauma patients are usually an infrequent occurrence, but they are severe and it is important to be prepared for them. Pediatric patients are also more complicated almost all the equipment, medications, and even vital signs parameters are different depending on the age/weight/height of the patient. This makes evaluating and managing a pediatric patient more complex and nuanced. 

The Broselow Cart is designed to have the proper equipment by weight range, but can also be used in conjunction with the broselow tape if a weight cannot be obtained.

 Let's set the scene, we get a notification that they're bringing in a 6 month old, unresponsive, 5 minutes out. 

To set up the resus room for this patient, we check that there is an appropriate infant BVM on the Broselow cart, place the backboard on the bed along with the Broselow tape, and crack open the cart.

When you open the drawers of the Broselow cart, it may be overwhelming if you have never seen the contents before. The first drawer is medications that are commonly used in pediatric resuscitations.

Be aware that both the cardiac arrest epi and the anaphylaxis epi are in here, the beige tan colored box has the cardiac arrest epi which is lower concentration higher volume as the medication is given IV, while the white box with  the pink star has the anaphylaxis epi which is a higher concentration and lower volume as the medication is given IM.

Next you open the bottom drawer and take note that the laryngoscope handles and McGill Forceps are in here.

Just as you open the pink/red drawer, the patient rolls in with EMS:

6 month old female who just started eating solids, had eggs and peanuts for the 2nd time in her life today. Parent states that the patient had 1 episode of vomiting and thought the patient just ate too much and let the patient rest in the crib. Reports that after completing chores, they went to check on the patient 30 minutes later and noticed her face and body was red, swollen, and she was having difficulty breathing so EMS was called. Upon EMS arrival, patient was given 0.01mg/kg IM epinephrine, about 10 minutes ago. 

Upon arrival in the ED, patient appears lethargic, swollen face, wheezing throughout.

Vitals: HR 190bpm, RR 60, BP 60/30, O2 sat 80% on NRB. 

While a nurse is attempting to get an IV, you tell another nurse to give the patient another dose of 0.01mg/kg epi, get a second IV and administer IV fluids (20mL/kg or 140mL of normal saline), ask pharmacist to prepare 0.1mcg/kg/min epinephrine drip, and prepare for intubation anticipating a difficult airway, call anesthesia. Ask RT to bag the patient with the infant BVM.

You turn around to collect your supplies and the pink/red drawer looks like this:

Most of the airway equipment is on the left section with the ETTs being stored in the middle. If multiple people are using this cart, it will likely not be organized so just knowing what is in the drawer itself is the most important. 

For this patient I would grab an OPA, PEEP valve, the small hyper-angulated rigid stylet and the LoPro S1 blade from the left side of the drawer, and under the BP cuffs to get the 3.5mm uncuffed ETT. As a backup, I will get the 6Fr stylet as well as the miller blade and a blade handle for the most bottom drawer. Also, be sure to check that the suction on the wall is working and get the small Yankauer catheter hooked up. Find the makeshift needle cricothyrotomy kit which includes a 14G angiocath, a 3mL syringe, and adapter to 7.0mm ETT.

Next, ask the nurse to draw up ketamine 1.5mg/kg or 10.5mg, use the infant BVM with the PEEP valve to bag the patient, get a repeat set of vitals, and attempt to intubate the patient.

We never know what may be rolling through those doors, so it is important to be ready for anything and everything. 

For this Trauma Tuesday we will go through a pediatric trauma case based on a case that I was a part of 2+ years ago while also reviewing some trauma reminders and the rest of the Broselow Cart!

6 y/o male brought in to resus 51 as a level 1 trauma, intubated after being rolled over by a car that reversed onto the sidewalk while the patient was crouched down and playing next to the curb. EMS reports that patient was hypoxic and unresponsive, intubated, vitals improved.

Upon arrival in the ED, trauma team and peds ED team at bedside.

Vitals: HR 135bpm, RR bagged at 18, BP 100/60, O2 sat 93% bagged

Airway - intubated, Breathing - bilateral breath sounds, Circulatory - distal pulses intact, tachycardic.

e-FAST negative, Primary survey - large right sided chest wall contusion and ecchymosis, Secondary survey - large ecchymosis on the right upper back.

CXR with large right hemothorax, PXR negative, patient was taken to CT scanner and found with large right hemothorax before going to Peds 31.

Patient's O2 saturation dropping from 93% to 85%, thought it was due to hemothorax, and a right sided chest tube was placed. 

Pause: 

One of the things that we should've done is open the Broselow cart prior to when the patient initially arrived in Resus 51, I think we estimated his weight to be 20kg by the Broselow tape but did not open the cart since the patient was already intubated. Even though it was not used in this case, we should get in the practice of opening the cart whenever a pediatric resus patient arrives.

One of the barriers to opening the cart is not knowing what is in the cart, so the POTD from yesterday gave an overview, and here are the rest of the drawers. Everything contained in each drawer is the same, just different sizes for the different estimated weights of the patient according to the Broselow tape.

In addition, all pediatric trauma patients need a trauma observation order, a recorded weight, and height, so there is a new tall block in peds resus 30 with a tape measure attached to measure our patient's height:

Here is the rest of the Broselow Cart:

This patient got a 24Fr Chest tube in the right chest with about 200cc of output, but the O2 saturation was not improving and patient desaturated to the low 80s. A CXR was obtained to confirm chest tube placement but it also revealed that the ETT tube was too high.

Upon review of the first CXR, it seems that the ETT tube still seemed slightly high but probably was in place and got dislodged as the patient was moved multiple times now. The peds attending and senior EM resident utilized video laryngoscopy and found the balloon above the cords. The patient started to desaturate to the 70s, the dislodged ETT was removed and they bagged the patient. Patient's O2 saturation improved to high 80s/low 90s and they reintubated the patient. After intubation, the patient's right chest tube put out another 200cc of blood and continuing, so the decision was made to take the patient to the OR and given MTP. In the OR, the patient arrested while they were performing a thoracotomy but they were unable to achieve ROSC.

Patient had a bronchial injury causing the large hemothorax and even with MTP and making it to the OR the patient died. It was a reminder that pediatric patients are able to compensate for the most part until they are not. It is a constant reminder that we have to stay vigilant and be prepared. We check the resus bays and review airway plans every shift in order to get ahead of it. Now let's keep the Broselow cart in mind for pediatric resuscitations!

Takeaways:

• Every pediatric trauma patient needs a recorded height, weight, and a trauma observation order.

• Open the Broselow cart before the patient arrives to review your equipment.

• Crack open the Broselow cart for any pediatric resuscitations!