Evaluation of tests performed to confirm the position of the Veress needle for creation of pneumoperitoneum in selected patients: a prospective clinical trial

Abstract

PURPOSE: To evaluate tests performed to confirm the position of the Veress needle inserted into the left hypochondrium for creation of pneumoperitonium. METHODS: One hundred patients were submitted to laparoscopic procedure with left hypochondrium puncturing. Needle positioning tests were evaluated. The aspiration test was considered positive when organic material was aspirated; the injection test was considered positive when no increased resistance to liquid injection was observed; the recovery test was considered positive when the liquid injected was not recovered; the saline drop test was considered positive when drops of saline in the syringe disappeared quickly; the initial intraperitoneal pressure test was considered positive when pressure levels were £ 8 mmHg. A positive aspiration test indicated iatrogenic injury, whereas a positive result in any of the other tests indicated that the tip of the needle was correctly positioned in the peritoneal cavity. Sensitivity (SE), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV) of the tests were calculated by correlating results considered true positives (a), false positives (b), false negatives (c) and true negatives (d), according to the formulas: SE = [a/(a + c)] x 100; SP = [d/(b + d)] x 100; PPV = [a/(a + b)] x 100; NPV = [d(c + d)] x 100. RESULTS: With regard to the aspiration test, SE and PPV were not applicable, SP was 100% and NPV was 100%. With regard to the injection test, SE was 0%, SP was 100%, PPV was inexistent and NPV was 90%. Both recovery and saline drop tests yielded the following results: SE was 50%, SP was 100%, PPV was 100% and NPV was 94.7%. The initial intraperitoneal pressure test yielded the following results: SE, SP, PPV and NPV were 100%. CONCLUSIONS: When inserting the Veress needle into the left hypochondrium, a negative aspiration test guarantees the absence of iatrogenic injury; the injection test is not reliable to determine incorrect needle positioning, but it accurately detects correct needle positioning; recovery and saline drop tests are not reliable to determine correct needle positioning, but they accurately detect incorrect needle positioning; the initial intraperitoneal pressure test is reliable to determine both correct and incorrect needle positioning, and proved to be the most reliable of the tests analyzed.

Laparoscopy Pneumoperitoneum Fuzzy Modeling

“…The evaluation mechanisms for iatrogenic vascular and visceral injuries when using the Veress needle puncture approach are employed both in the needle puncture insertion and the gas insuflation verificati on. While the first one is verified by performing the Five Tests [5], the insuflation can be accomplished by finding out a function that describes the intraperitoneal pressure behaviour according to the gas volume injected [6], for instance, when using statistical analysis. An alternative to statistical analysis, as previously mentioned, is to employ fuzzy analysis as proposed in this paper (Fig.…”

“…After needle insertion, the five tests encompassing the ( i) aspiration test (AT), (ii) injection test (IT), (iii) recovery test (RT), (iv) saline drop test (SDT), and (v) initial intraperitoneal pressure test (IIPT) 12 10 [mmHg] were performed [1], [12]. Details for such tests may be found in [5]. The IT, RT and SDT were performed and recorded according to a pre-established protocol, one after the other, regardless of the results (positive or negative).…”

“…Differences in amplitude reflect the inherent, distinct physiological cha rac-teristics for a random population chosen in this study. This intensional random population is due to the interest in findi ng out a universal, more general model mainly when compared to results obtained for a limited, homogeneous physiological characteristic of uniforme population in [5]. Higher amplitude refers to patients with great wall complacency (elasticity), for instance, in recent pregnant women as well as multiple pregnancies in contrast to patients with previous abdominal surgeries that mostly present reduced amplitude.…”

“…In order to minimize or avoid iatrogenic injuries due to the blind needle puncture there are five tests to verify whether t he tip of the needle is in the peritoneal cavity [5]. Nevertheless, these procedures reffer only to the access moment of the needle insertion but not to the gas insuflation.…”

“…Related to the second step procedure it requires a distinct method of evaluation in order to verify the correctness, or not, of the needle tip positioning. This evaluation can be verified, for instance, by measuring the intraperitoneal pressure in time as well as the volume of gas into the abdomen in time at different pre-established time-points [5] yielding two distinct functions (or tables). The direct relationship of the pressure and volume of the gas as a reliable parameter of safe gas insuflation is investigated by employing statistical analysis in [6].…”