Biomedical subjects

T Junghans

Publications and source records attributed to T Junghans.

23 records · Page 2Linked to original sources

PubMed1997

Effects of pneumoperitoneum with carbon dioxide, argon, or helium on hemodynamic and respiratory function.

OBJECTIVE: To evaluate the effects of pneumoperitoneum with carbon dioxide, argon, and helium; different abdominal pressures (ie, 8, 12, and 16 mm Hg); and different positions (ie, head up, head down, supine) on hemodynamic and respiratory function in a porcine model. DESIGN: Prospective randomized trial. SETTING: Animal research laboratory. ANIMALS: Eighteen pigs weighing 25.5 +/- 6.9 kg (mean +/- SD). INTERVENTIONS: General anesthesia with endotracheal intubation. Implantation of pulmonal artery catheter and central venous line in jugular vein and catheters in femoral artery and vein. Carbon dioxide, argon, or helium was insufflated through a cannula in the left upper quadrant. The type of gas was randomly assigned to each animal. After recording baseline values at the beginning and at the end without pneumoperitoneum, each animal was placed in 1 of the 3 positions and under 1 of the 3 pressures kept by the insufflator. After 15 minutes of adaptation to the new circumstances, all factors were recorded. This procedure was repeated until all 9 combinations of pressures and positions were evaluated. MAIN OUTCOME MEASURES: Cardiac output; heart rate; stroke volume; right ventricular stroke work; pressures in the pulmonal artery, vena cava, and femoral artery and vein; systemic vascular resistance; respiratory pressure; tidal volume; pH; base excess; oxygen partial pressure; and carbon dioxide partial pressure. RESULTS: The type of gas did not affect cardiac output. Only carbon dioxide demonstrated negative effects on respiratory function. Argon markedly increased afterload. Carbon dioxide increased central venous and mean arterial pressure, which was only moderate using helium. A head-up position decreased cardiac output and central venous pressure and increased mean arterial and peripheral venous pressures, which were partly compensated in a head-down position. An intraperitoneal pressure of 16 mm Hg increased peripheral and central venous pressures, heart rate, and respiratory pressure, and decreased cardiac output, tidal volume, and pH. CONCLUSIONS: Helium may be an alternative gas to establish pneumoperitoneum because it does not have any effect on respiratory function and has only a moderate effect on hemodynamic function. Argon insufflation has some hemodynamic disadvantages. An intraperitoneal pressure greater than 12 mm Hg and a head-up position should be avoided because both have a markedly negative effect on respiratory and hemodynamic factors.

Animals↗

PubMed1997

Intermittent sequential compression of the lower limbs prevents venous stasis in laparoscopic and conventional colorectal surgery.

PURPOSE: This study was designed to evaluate the influence of intraoperative intermittent sequential compression (ISC) on venous blood return from the lower limbs during laparoscopic and conventional colorectal colectomy. METHODS: Fifty patients undergoing laparoscopic (n = 25) or conventional (n = 25) colorectal surgery were included in a prospective study. Peak venous flow (PFV) and the cross-sectional area (CSA) of the femoral vein were assessed by Doppler ultrasound examination intraoperatively. RESULTS: Age, gender, and body mass index were comparable between both groups. Baseline PFV was 21 +/- 6.6 cm/s in the conventional and 18.4 +/- 6.4 cm/s in the laparoscopic group (P = 0.2). ISC increased PFV to 156 +/- 29 percent of the baseline value in the conventional group and to 161 +/- 29 percent in the laparoscopic group. PFV decreased after abdominal insufflation to 127 +/- 19 percent of the baseline value in the laparoscopic group and after laparotomy to 134 +/- 27 percent in the conventional group (P = 0.3). PFV decreased slightly in both groups during surgery but remained well above the baseline value. Baseline CSA was 1.02 +/- 0.17 cm2 in the conventional group and 1 +/- 0.23 cm2 in the laparoscopic group. ISC decreased CSA to 0.91 +/- 0.18 cm2 (conventional) and 0.85 +/- 0.18 cm2 (laparoscopic) after initiation of ISC. CSA was 0.92 +/- 0.18 cm2 after abdominal insufflation in the laparoscopic group, and it was 0.93 +/- 0.18 cm2 after laparotomy in the conventional group (P = 0.4). During surgery, there were no differences in absolute CSA or CSA changes compared with the baseline value in both groups. Postoperative circumference of the calf and thigh were not different between both groups. Postoperative thromboembolic complications did not occur. CONCLUSION: ISC effectively increases venous blood flow from the lower limbs during conventional and laparoscopic colorectal resections and may decrease the risk of postoperative deep vein thrombosis. Therefore, ISC is strongly recommended in every prolonged laparoscopic procedure.

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PubMed1997

[Value of laparoscopic technique in primary colorectal carcinoma].

Patients who had undergone elective resection for primary colorectal cancer were included in a prospective study. The purpose of the study was to specify the current role of laparoscopic surgery in the treatment of colorectal cancer. Therefore, the reasons for performing the resection conventionally were documented under the general guideline that all colorectal cancer should be resected laparoscopically. Of 111 patients treated in 1995, only 22 underwent a laparoscopic resection and 4 patients a laparoscopic-assisted resection. Age, sex and tumor stage were comparable between groups. Operative time was longer in the laparoscopy group; duration of postoperative ileus and postoperative hospital stay were shorter. The most frequent indications for using a conventional approach were rectal cancer (n = 29), adhesions (n = 15), randomly selected patients (n = 14) and advanced cancer (n = 12). Cardiovascular risk factors were not so important. Laparoscopic techniques were only applied in a minority of patients with colorectal cancer (24-37%). Laparoscopic sphincter-preserving surgery is currently not recommended for rectal cancer in the middle and lower rectum. General risk factors are rarely a contraindication for a laparoscopic approach.

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PubMed1997

Does pneumoperitoneum with different gases, body positions, and intraperitoneal pressures influence renal and hepatic blood flow?

BACKGROUND: Because of the well-known negative effects of carbon dioxide pneumoperitoneum on the hemodynamic and respiratory system, it was questionable how pneumoperitoneum may affect hepatic and renal blood flow. Therefore the influences of different gases, different intraperitoneal pressures, and different body positions on hepatic and renal blood flow were investigated in a porcine model. METHODS: Cardiac and hemodynamic function were monitored by means of implanted catheters in the pulmonary artery and the femoral vein and artery. Renal and hepatic blood flow were recorded with a transonic volume flow meter placed at the renal and hepatic arteries and the portal vein. Eighteen animals were randomly assigned to receive one of three insufflation gases (carbon dioxide [CO2], argon, or helium. After baseline recording, one of three intraperitoneal pressures (8, 12, or 16 mm Hg) and one of three body positions (supine head up, or head down) were randomly chosen. After an adaptation time of 15 minutes, all data were recorded for 15 minutes. This was repeated until all nine combinations had been investigated. The end points of the study were blood flow in the hepatic and renal arteries and the portal vein, cardial output, systemic vascular resistance, and central venous pressure. RESULTS: Total liver blood flow was reduced on relation to intraabdominal pressure, head-up position, and argon insufflation. Arterial hepatic blood flow was reduced by the head-up position and argon insufflation. Portal venous blood flow decreased with the pig in the head-up position, with increased intraabdominal pressure, and argon insufflation. Renal blood flow was reduced by the head-up position and increased pressure. There was no correlation (p < 0.6) between systemic hemodynamic parameters (cardiac output, central venous pressure, and systemic vascular resistance) and hepatic and renal blood flow. CONCLUSIONS: Head-up position and intraperitoneal pressure greater than 12 mm Hg should be avoided during laparoscopic surgery because they compromise hepatic and renal blood flow. Argon insufflation impairs liver blood flow. However, helium may be advantageous compared with CO2 insufflation.

Animals↗

PubMed1997

[Progress in laparoscopic sigmoid resection in elective surgical therapy of sigmoid diverticulitis].

The full significance of laparoscopic technique in elective surgery of sigmoid diverticulitis has yet to be determined. However, it seems worthwhile to evaluate how minimally invasive surgery could be integrated into the surgical treatment of diverticulitis disease. Between January 1995 and August 1996, 26 patients with sigmoid diverticulitis underwent elective surgery. Following diagnostic laparoscopy, seven patients were treated with primary conventional resection, 15 patients with laparoscopic resection and four patients with laparoscopic-assisted surgery. One laparoscopic resection had to be converted to a median laparotomy. Postoperative complications (n = 2) only appeared in the group of conventional resections. Conventional resections required less time than laparoscopic or laparoscopic-assisted resections, but postoperatively, patients with laparoscopic resection were able to defecate sooner and required a shorter hospital stay. For 60% of the patients with diverticulitis disease of the colon, elective laparoscopic resection may prove to be the best alternative of surgical treatment. In selected patients it is a sound technique with a low complication rate. We recommend that all patients with diverticulitis disease requiring elective surgery undergo diagnostic laparoscopy to determine whether or not laparoscopic resection is a viable option.

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