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Thursday, March 29, 2018

From the SIR Residents and Fellows Section (SIRRFS)

Teaching Topic: Value of Antibiotic Prophylaxis for Percutaneous Gastrostomy: A Double-Blind Randomized Trial

Ingraham CR, Johnson G, Albrecht EL, et al. Value of antibiotic prophylaxis for percutaneous gastrostomy: a double-blind randomized trial. J Vasc Interv Radiol. 2018; 29: 55-61.

Since its development in 1980, percutaneous radiologic gastrostomy (PRG), also known as radiologically inserted gastrostomy (RIG) or simply percutaneous gastrostomy (PG), has become a common, safe, and effective option for the delivery of nutritional support to treat or prevent malnutrition in patients where oral intake is contraindicated. While surgical gastrostomy, performed endoscopically, known as percutaneous endoscopic gastrostomy (PEG), is the traditional gold standard, there are many advantages for fluoroscopically placed gastrostomy. In a meta-analysis, radiologic gastrostomy had a higher rate of successful placement than surgical (99.2% vs. 95.7%, p < .001) with a reduced major complication rate (5.9% vs. 9.4%, p <.001). [1] Additionally, radiological placement does not require general sedation and can avoid passage through the oropharynx preventing tumor seeding in head and neck cancer cases. Likewise, the avoidance of the oral passage and the prevention of contamination with oral flora is frequently cited as a major benefit of radiological placement. [2,3] In this study, Dr. Ingraham et al. conducted a double-blinded, randomized controlled trial to compare peristomal infection rates after prophylactic antibiotics in percutaneous gastrostomy.

The guidelines from the SIR Standards and Practice Committee recommends routine administration of prophylactic antibiotics in “pull technique” gastrostomy tube placement (transoral access), but did not find a consensus for prophylaxis administration with the “push technique” (transabdominal access). This study measured the rates of peristomal infection in 122 patients who received push-type gastrostomy placement in three study arms- placebo (n=34), prophylactic antibiotic administration (n=34), or in an observational group if they were already receiving antibiotics for another indication (n=68). All patients received a 16-F Deutsch gastrostomy tube (Cook Medical, Bloomington, Indiana), a pigtail catheter, placed over a stiff wire through an 18-gauge needle centered within 3 absorbable gastropexy sutures. Patients in the treatment arm received 1 g of intravenous cefazolin or 600 mg of intravenous clindamycin in those with allergies. A blinded evaluator examined the stoma site for subjective signs of infection at 3-5 days, 7-10 days, 14-17 days, and 28-30 days.

Because patients were lost to follow up or started on antibiotics for unrelated infections, analysis was restricted to the early time period (<10 days). During this period, 4/34 (11.8%) patients in the placebo arm and 0/34 (0.0%) in the treatment arm were found to have stoma site infections. This trend was not found to be statistically significant under intention-to-treat analysis (p = .057). However, under per-protocol analysis the difference between infection rate of 4/30 (13.3%) patients in the placebo arm and the 0/32 (0.0%) in the treatment arm was statistically significant (p=.049). Only one patient was found to have an infection in the observation arm, but compared to the placebo this difference was not significant in intention to treat (p=.078) or per protocol (p=.063) analysis.

Clinical Pearls

How can you tell if a stoma site is infected? How common is stoma site infections?

The authors of this study used an 11-point scale based on erythema, induration, and exudate that was originally developed for studying antibiotic prophylaxis in PEG placement. The points were distributed based on the “presence of erythema (0, none; 1, ≤ 5 mm; 2, 6–10 mm; 3, 11–15 mm; 4, ≥ 15 mm), induration (0, none; 1, ≤ 10 mm; 2, 11–20 mm; 3, ≥ 20 mm), and exudate (0, none; 1, small serous; 2, moderate serous; 3, large serous ± sanguineous; 4, purulent).”

According to the review of the literature in the SIR Antibiotic Prophylaxis guidelines, infections in transoral access range from 4%-30%, but infections in retrospective series of transabdominal access without antibiotics ranged from 0-2%. [4,5]. However, a retrospective review of head and neck cancer patients who underwent transabdominal gastrostomy found 15% infection rate among the patients that were not treated with prophylaxis. [6] Patients with head and neck cancer were not excluded from the study discussed in this Teaching Topic- 9 patients received placebo, 8 received treatment, and 15 were in the observation arm. It is possible this played a part in the relatively high (11.8-13.3%) infection rate found in this study.

What is the difference between the methods of radiologic gastrostomy?

While the SIR antibiotic guidelines only differentiate between the “push” and “pull” methods, there are many different variations on fluoroscopically placed gastrostomy tubes. For antibiotic consideration, traversing the oral cavity is likely the biggest consideration.

The classical radiologically inserted gastrostomy is a Seldinger technique that consists of insufflating the stomach through a nasogastric tube then percutaneously passing a needle into the stomach. A wire is then passed and a gastrostomy tube is then passed over the wire. This technique was first described in 1981 by Preshaw and modified to include percutaneous gastropexy by Brown et al. in 1986. [7,8] This is called the “push” method as you push the gastrostomy tube percutaneously into the stomach.

Transoral access allows for larger tube sizes, the same as placed endoscopically. This method utilizes a similar technique to enter the stomach before passing a catheter retrograde through the esophagus and out the oral cavity where a gastrostomy tube is advanced over the wire. This is what is referred to as the “pull” method as you pull the gastrostomy tube out of the stomach into its final position. It is standard of care to give antibiotics with this method.

Questions to Consider:

What is the difference between intention-to-treat and per protocol analysis?

Intention to treat (ITT) and per protocol are different methods for analyzing results of randomized controlled trials. ITT includes all subjects as originally randomized, regardless of completion of treatment, to compare outcomes of the groups. Per protocol only includes subjects who completed treatment and outcome assessment. ITT reduces the possible bias if attrition, non-compliance, or protocol mistakes were non-random. Broadly speaking, ITT measures the efficacy of the treatment protocol, while per protocol measures the outcomes of the specific treatment. In this study, patients were given antibiotics for other infections, thus violating the protocol and introducing a possible bias. These patients were excluded from the per protocol analysis which was found to be statistically significant. It is important to consider both ITT and per protocol when making clinical decisions based on trial data.

Additional Sources:

1. Wollman B, D’Agostino HB, Walus-Wigle JR, Easter DW, Beale A. Radiologic, endoscopic, and surgical gastrostomy: an institutional evaluation and meta-analysis of the literature. Radiology. 1995;197(3):699–704.

2. Shin JH, Park A-W. Updates on percutaneous radiologic gastrostomy/gastrojejunostomy and jejunostomy. Gut Liver. 2010;4(Suppl 1):S25–31.

3. Sutcliffe, J, Wigham, A, Mceniff, N, Dvorak P, Uberoi R. CIRSE Standards of Practice Guidelines on Gastrostomy. Cardiovasc Intervent Radiol. 2016;39(7):973.

4. Venkatesan, A.M., Kundu, S., Sacks, D. et al. Practice guidelines for adult antibiotic prophylaxis during vascular and interventional radiology procedures. Written by the Standards of Practice Committee for the Society of Interventional Radiology and Endorsed by the Cardiovascular Interventional Radiological Society of Europe and Canadian Interventional Radiology Association [corrected]. J Vasc Interv Radiol. 2010; 21: 1611–1630

5. Wollman, B. and D’Agostino, H.B. Percutaneous radiologic and endoscopic gastrostomy: a 3-year institutional analysis of procedure performance. AJR Am J Roentgenol. 1997; 169: 1551–1553

6. Cantwell, C.P., Perumpillichira, J.J., Maher, M.M. et al. Antibiotic prophylaxis for percutaneous radiologic gastrostomy and gastrojejunostomy insertion in outpatients with head and neck cancer. J Vasc Interv Radiol. 2008; 19: 571–575

7. Preshaw RM. A percutaneous method for inserting a feeding gastrostomy tube. Surg Gynecol Obstet. 1981;152(5):658–60.

8. Brown AS, Mueller PR, Ferrucci JT. Controlled percutaneous gastrostomy: nylon T-fastener for fixation of the anterior gastric wall. Radiology. 1986;158(2):543–5.

Post Author:
Charles Hyman, MS4
Chair, Communications Committee, SIRRFS
Warren Alpert Medical School of Brown University

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