Effects of needle gauge and syringe size on small intestinal leakage at injection sites

Abstract

Objective To determine the influence of needle gauge, syringe volume, and syringe size on needle tract leakage after injection in porcine jejunum. Study design Ex vivo experiment. Sample population Three hundred sixty jejunal segments from 20 feedlot pigs. Methods Fresh porcine intestines were divided into 5‐cm or 10‐cm segments and randomly assigned to the one of nine treatment groups: 25‐gauge, 22‐gauge, and 20‐gauge needles attached to full 12‐mL, half‐full 20‐mL, and full 20‐mL syringes (n = 20/group). The jejunal segments were occluded with Rochester‐Carmalt forceps prior to injection of diluted India ink. Injection time and leakage were noted by a blinded observer. Multivariate analysis was used with segment size, needle gauge, volume infused, time to inject per milliliter, and syringe size as variables. Results Leakage occurred in 36% of 5‐cm and 15% of 10‐cm segments and was immediate without palpation in 33.8% and 11% of segments, respectively. Protective effects were seen for 22‐gauge needles in both 5‐cm (P = .002) and 10‐cm (P = .001) segments, whereas injection of 20 mL had a higher odds ratio of leakage compared with injection of 10 mL and 12 mL in 5‐cm segments (P = .003). Conclusion Injections with 22‐gauge needles reduced the frequency of leakage, while 20 mL instilled in 5‐cm segments increased the frequency of leakage in intact segments of porcine jejunum. Clinical significance Injection with a smaller syringe size attached to a 22‐gauge needle through a 10‐cm segment of small intestine may lower the frequency of leakage from the injection site, but influence on the detection of surgical site leakage remains unknown.

Ex vivo comparison of leak testing of canine jejunal enterotomies: Saline infusion versus air insufflation

“…Recently, Brand et al reported that use of a 22 gauge needle for saline infusion minimized leakage from the transmural defect, while use of a 25 gauge needle increased the risk of leakage. 33 They proposed that the surgeon had to generate greater pressure to infuse the saline through the 25 gauge needle, resulting in greater micromotion of the needle at the transmural defect and "coring" of the intestinal wall. While a larger, 18 gauge, IV catheter was used in the present study, leakage was not observed from the catheter site in any enterotomy constructs.…”

“…Thus, the present study established and validated a protocol for intraluminal air insufflation of the small intestine, which may be used for future cadaveric studies or even adapted for intraoperative use. Recently, Brand et al reported that use of a 22 gauge needle for saline infusion minimized leakage from the transmural defect, while use of a 25 gauge needle increased the risk of leakage 33 . They proposed that the surgeon had to generate greater pressure to infuse the saline through the 25 gauge needle, resulting in greater micromotion of the needle at the transmural defect and “coring” of the intestinal wall.…”

“…One striking difference between leak testing in veterinary and human medicine is the method by which leak testing is performed. In dogs, intraluminal infusion of a fixed volume of saline into 10 cm of canine intestine 31,32 using a 22 gauge needle 33 has been validated to produce an intraluminal pressure of 25 mmHg, the maximum reported physiologic peristaltic pressure 34 . While intraluminal saline infusion has been sparsely reported in human medicine, 17,25,27 often with the addition of methylene blue, 28 the preponderance of literature demonstrating significant reductions in postoperative leakage have employed intraluminal air insufflation 18,20,23,24,26,29,30 .…”

Intraoperative surgeon probe inspection compared to leak testing for detecting gaps in canine jejunal continuous anastomoses: A cadaveric study

“…We used a plastic manometer over a pressure transducer for LT, as this is an affordable easily sterilizable instrument 26 . Our assistant injected fluid manually 26–28 rather than using a syringe pump, despite possible resulting fluctuations in fluid rate administration, to closely mimic a clinical scenario. However, we did not use 18G catheters through the intestinal wall for LT as done by other investigators, which would have better mirrored the clinical setting 12,14,26,27,40,45 .…”

“…There are multiple intraoperative techniques reported to assess for gaps or leaks between suture bites in veterinary medicine, including milking ingesta across an anastomosis 2,23 or injecting saline to identify leaks from the suture line 1,2,4,18,26–28 . In a 2019 literature review, Ellison et al recommended performing leak testing (LT) for all intestinal closures 29 .…”