Cardiopulmonary effects of the laparoscopic pneumoperitoneum in a porcine model of adult respiratory distress syndrome

Factors affecting the selection of minimally invasive surgery for stage 0/I colorectal cancer

PURPOSE

To evaluate which factors affect selection of minimally invasive surgery (MIS) or open procedures for patients with stage 0/I colorectal cancer. The short-term and oncologic outcomes of MIS were also compared to those of open procedures.

METHODS

A total of 181 consecutive patients underwent either MIS (laparoscopy: n = 146, robot: n = 8) or open (n = 27) colorectal resection for stage 0/I disease.

RESULTS

Elderly patients (≥80) were more common in the open procedure group (22.2%) than the MIS (7.8%) group (p = .02). Surgeon A performed more MIS procedures than surgeon B (p = .003). There were no differences in the 30-day complication rate between open (37%) and MIS (21.4%) groups (p = .08). Time to tolerable diet (p = .002) and length of hospital stay (p = .02) were shorter in the MIS group. There were no differences in the cancer-specific survival (p = .71) and recurrence-free survival rates (p = .67) between open and MIS procedures.

CONCLUSIONS

Patient factors (old age) and surgeon factors (surgeon B) were barriers to the choice of MIS. Old age and operating surgeons were not associated with adverse 30-day complications. The short-term and oncologic outcomes of MIS were comparable to those of open procedures. It is safe to expand the indication for MIS to elderly patients.

Overview of the pathology of three widely used animal models of acute lung injury

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are syndromes of acute diffuse damage to the pulmonary parenchyma by a variety of local or systemic insults. Increased alveolar capillary membrane permeability was recognized as the common end organ injury and a central feature in all forms of ALI/ARDS. Although great strides have been made in understanding the pathogenesis of ALI/ARDS and in intensive care medicine, the treatment approach to ARDS is still relying on ventilatory and cardiovascular support based on the recognition of the clinical picture. In the course of evaluating novel treatment approaches to ARDS, 3 models of ALI induced in different species, i.e. the surfactant washout lavage model, the oleic acid intravenous injection model and the endotoxin injection model, were widely used. This review gives an overview of the pathological characteristics of these models from studies in pigs, dogs or sheep. We believe that a good morphological description of these models, both spatially and temporally, will help us gain a better understanding of the real pathophysiological picture and apply these models more accurately and liberally in evaluating novel treatment approaches to ARDS.

Laparoscopic spray application of fibrin sealant effects on hemodynamics and spray efficiency at various application pressures and distances

BACKGROUND

Laparoscopic resections of parenchymal organs are increasingly performed. However, little is known about the effects of laparoscopic fibrin sealant spray applications on intraabdominal pressure (IAP) and hemodynamics.

METHODS

Cardiac and pulmonary monitoring was performed via two central venous pressure lines in the thoracic and abdominal vena cava, a pulmonary artery catheter, and a peripheral artery line. Air was sprayed into the abdomen at pressures of 2, 3, and 4 bar for 30 s. According to the group, a valve on a trocar was open or closed. To optimize fibrin sealant application, the sealant was sprayed at three different application pressures (2, 2.5, and 3 bar) and distances (2, 3.5, and 5 cm).

RESULTS

All spray simulations caused a significant increase in the IAP. During the first 10 s of spraying, the IAP increase was 5 mmHg or less, but rose rapidly during the last 20 s of spraying. The IAP increase resulted in decreased pulmonary compliance. Pulmonary resistance and the central venous pressures of both the thoracic and abdominal vena cava increased. At application pressures of 3 and 4 bar, the IAP increase was greater than 2 bar of pressure, reaching IAP values exceeding 35 mmHg. Spray mist formation was primarily dependent on application pressure, whereas clot formation and surface coverage depended on both application pressure and distance. The best results were achieved with an application pressure of 2.5 bar and a distance of 5 cm from the surface.

CONCLUSIONS

This study shows that fibrin sealants can be used safely in laparoscopic procedures. Keeping the spray periods short and allowing air to escape from the abdomen can minimize the IAP increase. According to our results, a laparoscopic spray application of fibrin sealant should start with an insufflation pressure of 10 mmHg, an application pressure of 2.5 bar, and an application distance of 5 cm with a valve on the trocar left open.

The Physiologic Effects of Laparoscopy

The use of laparoscopic approaches to surgical disease continues to advance quickly. Laparoscopy applied to oncologic surgery continues to be debated. We review the experience of laparoscopy as it relates to surgery for tumors. Specifically, we discuss the physiologic changes and tumor response to laparoscopy, as well as the current concepts explaining port site recurrence.

Effects of pneumoperitoneum on hemodynamic and systemic immunologic responses to peritonitis in pigs

BACKGROUND

Experimental evidence supporting the safety of laparoscopic intervention during sepsis is limited. The purpose of this study was to evaluate the effects of pneumoperitoneum on immunologic and hemodynamic responses to peritoneal sepsis.

MATERIALS AND METHODS

A porcine model of peritonitis was created using an intraperitoneal autologous fecal inoculum. Pigs were then subjected to one of four procedures 24 h postinoculation (n = 6 per group): laparotomy, CO(2) laparoscopy, helium laparoscopy, and anesthesia only (1.5% isoflurane in 100% O(2), mechanical ventilation). Venous blood samples were obtained prior to inoculation, and at 24 (prior to procedure), 30, 48, 72, and 96 h postinoculation to determine white blood count (WBC) with differential, C-reactive protein (CRP), tumor necrosis factor, and bacteremia. Heart rate, end-tidal CO(2) (ETCO(2)), mean arterial blood pressure (MAP), and arterial blood gas variables were also measured at baseline and every 30 min throughout the procedure.

RESULTS

Postoperative blood cultures confirmed systemic bacteremia in all groups at all time periods postinoculation. Following inoculation, WBC, band cell count, and CRP remained elevated above baseline in all groups throughout the study (P < 0.01). However, no significant differences in these parameters were observed among groups. In the CO(2) laparoscopy group, MAP, ETCO(2), and arterial pCO(2) were increased above baseline, while pH was decreased throughout the procedure (P < 0.01).

CONCLUSIONS

In this animal model of peritonitis, CO(2) pneumoperitoneum induced hypercapnia, acidemia, and systemic hypertension intraoperatively, without a discernable effect on systemic immune function.

Effects of abdominal Co2 insufflation on renal and hepatic blood flows during acute hemorrhage in anesthetized pigs

OBJECTIVE

To evaluate the consequences of laparoscopy during hemorrhage, we studied the respiratory, renal, and hepatic blood flow changes induced by abdominal Co2 insufflation during severe hemorrhage in anesthetized pigs.

DESIGN

Prospective animal study.

SETTING

University research laboratory.

SUBJECTS

Anesthetized and ventilated pigs (n = 18).

INTERVENTIONS

The right carotid artery was cannulated to measure mean arterial pressure. A pulmonary artery catheter was inserted to measure mean pulmonary arterial pressure and cardiac output. After a midline abdominal incision, three flow probes were positioned around the portal vein, the hepatic artery, and the renal artery to measure portal vein blood flow, hepatic artery blood flow, and renal blood flow. To induce hemorrhage, blood was withdrawn until mean arterial pressure reached 50 mm Hg. Laparoscopy was mimicked by insufflating Co2 until intra-abdominal pressure reached approximately 15 mm Hg. Measurements were collected during hemorrhage, Co2 abdominal insufflation, and the combination of both interventions.

MEASUREMENTS AND MAIN RESULTS

Severe pulmonary hypertension and hypercapnic acidosis occurred during abdominal Co2 insufflation. However, the abdominal Co2 insufflation did not aggravate the cardiac output and total hepatic blood flow changes induced by acute hemorrhage, whereas the combination of hemorrhage and abdominal Co2 insufflation markedly altered renal blood flow.

CONCLUSIONS

These results suggest that renal function must be monitored carefully when performing laparoscopy in trauma patients. In contrast, hepatic perfusion seems well preserved.

Applicability of laparoscopic surgery for colorectal disease

BACKGROUND

The advantages of laparoscopic colorectal surgery for selected patients have been well established. However, the applicability of laparoscopic surgery in the whole population of patients with colorectal disease is not well known.

METHODS

A single-institution medical records review of 269 patients subjected to colorectal surgery was made. Of these, 206 open colorectal procedures were performed, and data were reviewed retrospectively. In addition, 63 patients were subjected to laparoscopy, and their data were recorded prospectively. An analysis of the existence of factors that contraindicate laparoscopic colorectal surgery was done. These factors were of two types: absolute (urgent intervention, severe cardiopulmonary disease, advanced liver cirrhosis, tumor invasion into adjacent organs, simultaneous major surgery) and relative (midrectal tumors, tumors in the transverse colon, bulky tumors, more than two previous infraumbilical operations, previous intestinal surgery, and previous peritonitis).

RESULTS

Factors that could contraindicate the laparoscopic approach were found in 118 patients (44%). The most common were urgent intervention (40%), midrectal tumors (19%), locally advanced cancer (13%), previous intestinal surgery (13%), and tumors >10 cm (6%). We considered 25% of the contraindications to be absolute and 19% relative. Taking these exclusion criteria into consideration when selecting patients for laparoscopic surgery, the conversion rate in our initial laparoscopic series (63 cases) was 13%.

CONCLUSION

The indication for laparoscopic surgery for patients with colorectal disease is superior to 60% (absolute 56%, relative 81%). When using appropriate selection criteria, the conversion rate may be maintained below 10%. Preoperative selection of patients with colorectal disease allows optimal use of the advantages of laparoscopic surgery.