Albino Augusto Sorbello

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

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 pounds 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.

Veress needle insertion in the left hypochondrium in creation of the pneumoperitoneum.

PURPOSE To test the efficacy of the puncture in the left hypochondrium as an alternative method. METHODS Sixty-two patients randomly distributed into two groups were studied: Group LH, puncture in the left hypochondrium (n=30), and Group ML, puncture in the abdominal midline (n=32). The following were assessed: needle positioning tests, number of failed attempts at needle insertion, and time needed for creation of pneumoperitoneum. Gas flow, volume and intraperitoneal pressure were recorded at every 20 seconds, until a 12 mmHg pressure was reached inside the peritoneal cavity. RESULTS A similar number of positive results for the needle positioning tests were observed in both groups. Two failed attempts to reach the peritoneal cavity were observed in Group ML and one in Group LH. The time necessary for the creation of pneumoperitoneum was on average 3 minutes and 46 seconds for Group LH, and 4 minutes and 2 seconds for Group ML. Average gas flow, volume and pressure were equivalent for both groups. CONCLUSION Puncture in the left hypochondrium was as effective as puncture in the abdominal midline for the creation of pneumoperitoneum.

Intraperitoneal pressure and volume of gas injected as effective parameters of the correct position of the Veress needle during creation of pneumoperitoneum.

OBJECTIVE The aim of this work was to establish reliable parameters of the correct position of the Veress needle in the peritoneal cavity during creation of pneumoperitoneum. METHODS The Veress needle was inserted into the peritoneal cavity of 100 selected patients, and a carbon-dioxide flow rate of 1.2 L/min and a maximum pressure of 12 mm Hg were established. Intraperitoneal pressure (IP) and the volume of gas injected (VG) were recorded at the beginning of insufflation and at every 20 seconds. Correlations were established for pressure and volume in function of time. Values of IP and VG were predicted at 1, 2, 3, and 4 minutes of insufflation, by applying the following formulas: IP = 2.3083 + 0.0266 x time +8.3 x 10(-5) x time(2) - 2.44 x 10(-7) x time(3); and VG = 0.813 + 0.0157 x time. RESULTS A strong correlation was observed between IP and preestablished time points during creation of the pneumoperitoneum, as well as between VG and preestablished time points during creation of the pneumoperitoneum, with a coefficient of determination of 0.8011 for IP and of 0.9604 for VG. The predicted values were as follows: 1 minute = 4.15; 2 minutes = 6.27; 3 minutes = 8.36; and 4 minutes = 10.10 for IP (mm Hg); and 1 minute = 1.12; 2 minutes = 2.07; 3 minutes = 3.01; and 4 minutes = 3.95 for VG (L). CONCLUSIONS Values of IP and VG at given time points during insufflation for creation of the pneumoperitoneum, using the Veress needle, can be effective parameters to determine whether the needle is correctly positioned in the peritoneal cavity.

Comparative study of the changes in partial pressure of plasma carbon dioxide during carbon dioxide insufflation into the intraperitoneal and preperitoneal spaces.

BACKGROUND We aimed to compare plasma concentrations of carbon dioxide (CO(2)) in dogs that underwent intra- and preperitoneal CO(2) insufflation. MATERIALS AND METHODS Thirty dogs were studied. Ten formed a control group, 10 underwent intraperitoneal CO(2) insufflation, and 10 underwent preperitoneal CO(2) insufflation. General anesthesia with controlled ventilation was standardized for all dogs. After stabilizing the anesthesia, blood samples were collected at predetermined times and were sent for immediate gasometric analysis. Analysis of variance was used for comparing variables. RESULTS The plasma CO(2) concentration in the intraperitoneal insufflation group increased significantly more than in the preperitoneal insufflation group and was significantly greater than in the control group (P < 0.05). The pH values in the intraperitoneal group were lower than in the preperitoneal group (P < 0.05). CONCLUSION The data from this study suggest that a greater plasma concentration of CO(2) is achieved by insufflation at constant pressure into the intraperitoneal space than into the preperitoneal space.

Criação do pneumoperitônio mediante punção com agulha de Veress no hipocôndrio esquerdo: ensaio clínico, prospectivo e randomizado

BACKGROUND: In the creation of the pneumoperitoneum with the Veress neddle, all reported incidents occurred during the puncture in the midline of the abdomen. Albeit rare, such type of incident has a high mortality rate as it normally severs the large vessels. The objective of this research is to test the efficacy of a safer alternative method of puncture in the left hipocondrium. METHODS: Sixty two patients, distributed randomly into two groups were studied. Group HE: puncture in the left hipocondrium (n = 30), and Group LM: puncture in the medline of the abdomen (n = 32). An evaluation was carried out of the results of the tests as to the positioning of the needle, the number of failed attempts to access the peritoneal cavity and the time taken for the creation of the pneumoperitoneum. Real flows, intraperitoneal pressure, and injected volumes were recorded at 20 second intervals, until pressure had reached 12mmHg. RESULTS: The results of the test regarding the positioning of the Needle were equally positive. There were two unsuccessful attempts at piercing in Group LM and one in Group HE. The time taken for the creation of the pneumoperitoneum was on average of 3 minutes and 46 seconds for Group HE and of 4 minutes and 2 seconds for Group LM. The average measures recorded regarding flow, pressure and volume were equivalent in each Group, respectively. The statistical analysis has demonstrated that piercing of the left hypocondrium was as effective in the creation of the pneumoperitoneum as it was the case as regards the piercing of the medium line of the abdomen. CONCLUSION: The left hipocondrium must be the preferred place for the puncture with the Veress needle so as to create the artificial pneumoperitoneum by the closed technique, as it entails a smaller risk.

Valor das provas de posicionamento da ponta da agulha de veress em punção do hipocôndrio esquerdo na instalação do pneumoperitônio

BACKGROUND: To evaluate tests for Veress needle tip placement intraperitoneally in the left hypochondrium for creating a pneumoperitoneum. METHODS: Needle tip placement tests were evaluated in one hundred patients using the left hypochondrium area. It was considered positive when: aspiration test (PA) -returned organic material; resistance test (PRes) - a low pressure was pushed on the syringe for the liquid infusion; recovery test (PRec) - no liquid was recovered after infusion; dripping test (PG) - drops drained quickly; test for initial intraperitoneal pressure (PPII) - levels were <= 8mmHg. Positive PA suggested bowel injury, while positive PRes, PRec, PG and PPII indicated that needle tip was adequately located in the peritoneal cavity. The Sensitivity ( SE) and Specificity ( SP ), as well as their predictive positive values (PPV) and predictive negative values ( PNV) of these tests were calculated using results correlation which were true-positives (a), false-positives (b), false-negatives (c) and true-negatives (d), accordingly to the formulas: SE =[a/ (a+c)]x100; SP =[d/(b+d)]x100; PPV=[a/(a+b)]x100; PNV=[d(c+d)]x100. RESULTS: If a positive PA had returned, SE and PPV did not fit, and SP=100% and PNV =100%. In the PRes, SE =0%, SP =100%, PPV = did not exist and PNV =90%. Both in the PRec and in the PG, results were for SE =50%, SP =100%, PPV =100% and PNV =94.7%. In the PPII test results were for SE, PPV and PNV =100%. CONCLUSION: Left hypochondrium negative PA guaranteed that bowel was not perforated; PRes test is a not accurate test for detection of the needle tip bad placement, however it accurately indicates its good positioning; PRec and the PG tests do not detect the adequate positioning, but they detect very well the inadequate positioning; PPII test shows with reliability both bad and good positioning of the needle, being the most trustworthy test among those studied.