Effect of the antiadhesive treatments, carboxymethylcellulose combined with recombinant tissue plasminogen activator and Seprafilm, on bowel anastomosis in the rat.

Abdominal adhesions are a significant cause of increased morbidity, mortality, and cost in patients undergoing abdominal surgery. Carboxymethylcellulose combined with recombinant tissue plasminogen activator (CMC + rtPA) and Seprafilm (sodium hyaluronate/carboxymethylcellulose bioresorbable membrane) have been shown to reduce adhesion formation in animal models. The effect these treatments may have on a healing bowel anastomosis is unknown. Forty-eight rats underwent a laparotomy and the distal colonic segment was transected and an anastomosis of the transected ends performed. Before abdominal closure one of three treatments - CMC + rtPA, Seprafilm, and saline (control) - was placed in the rat abdomen around the anastomosis. A necropsy was performed 75 to 96 hours later and bowel anastomosis adhesions were scored using an adhesion scale. The anastomosis strength was then evaluated using a saline infusion bursting pressure model. No difference was observed in the extent of adhesion formation involving the bowel anastomosis among all groups. No statistically significant difference was found among the groups in the bursting strength of the colonic anastomosis. We conclude that CMC + rtPA and Seprafilm do not significantly reduce colonic bowel anastomosis bursting strength in the rat model.

Comparison of antiadhesive treatments using an objective rat model.

Intraperitoneal adhesions are a significant problem (increased morbidity, mortality, and cost) for patients undergoing abdominal procedures. Although a variety of approaches (e.g., fibrinolytic agents, anti-inflammatory drugs, or barrier/separation methods) have been used with some success in preventing adhesions, a comparison of these different modalities has yet to be performed in a model that objectively measures intraperitoneal adhesion formation. Our objectives were to establish an objective, reproducible model of intraperitoneal adhesion formation and to establish efficacy of different treatment modalities in decreasing the strength and extent of intraperitoneal adhesions. In this two-part study, a rat model establishing an objective measure of both the strength and extent of intraperitoneal adhesions was used to compare different treatment modalities. Fibrinolytic agents [recombinant tissue plasminogen activator (rtPA), streptokinase, and urokinase], anti-inflammatory drugs (dexamethasone and tolmetin sodium), and barrier methods [sodium carboxymethylcellulose (CMC), and sodium hyaluronate] and a control group were compared in the first phase. In the second phase, the two most successful agents (rtPA, CMC) were compared both alone and in combination against a commercially available barrier agent (Seprafilm) and a control group. In the first phase of the study, rtPA was the only agent that had a statistically significant effect in decreasing the strength of adhesions. CMC was the only agent that demonstrated a decrease in the extent of adhesions, and the difference tended toward significance. In the second phase, the combination of rtPA and CMC showed a significant decrease in both the strength and extent of adhesions when compared with those of the control group. This decrease was also observed in the group treated with Seprafilm, which showed no difference from the rtPA + CMC group. We conclude that, in this reproducible adhesion model, only the combination of rtPA + CMC and Seprafilm significantly reduced both the strength and the extent of intraperitoneal adhesions.

Continuous peripheral nerve block catheter tip adhesion in a rat model.

BACKGROUND: Continuous peripheral nerve block (CPNB) has been used effectively in combat casualties from Iraq and Afghanistan to provide surgical anesthesia and extended duration analgesia during evacuation and convalescence. Little information is available concerning catheter tip tissue reaction with prolonged use. METHODS: Forty-eight male Sprague-Dawley rats were assigned (12 per group) to one of four catheter tip designs provided by Arrow International: group A, 20-gauge catheter with three side-holes and a bullet-shaped tip; group B, 19-gauge StimuCath catheter with coiled omni-port end with hemispherical distal tip; group C, 19-gauge catheter with single end-hole in conducting tip; group D, 19-gauge catheter with closed conducting tip with four side-holes. Following laparotomy, a randomly assigned catheter tip was sutured to the parietal peritoneal wall with the tip extending between experimental injuries created on the abdominal wall and cecum. After 7 days in situ, the catheter tips were removed from the adhesion mass using a force gauge, and the grams of force needed for removal were recorded. RESULTS: The mean force +/- standard deviation values were 1.09 +/- 1.21 g for group A, 21.20 +/- 30.15 g for group B, 0.88 +/- 1.47 g for group C and 1.60 +/- 2.50 g for group D. The variation of each catheter group mean force compared with that of group B was significant (P < 0.05). There was no significant difference in adhesion force between groups A, C and D. CONCLUSIONS: These results suggest that the manufactured design of a CPNB catheter tip can contribute to the adhesion of the tip in an intense inflammatory environment. This finding may have important clinical implications for CPNB catheters left in place for extended periods of time.

Supraclavicular continuous peripheral nerve block in a wounded soldier: when ultrasound is the only option.

The complex nature of combat-related injuries requires frequent operative interventions and prolonged analgesic therapy. The application of continuous peripheral nerve block (CPNB) has been an important anaesthetic tool in the management of combat soldiers wounded from the current conflicts. The severe, destructive nature of combat injuries makes placement of CPNB difficult or impossible using more common neurostimulation approaches. The use of ultrasound technology has improved our success in placing CPNB in the presence of such injuries. We report the application of ultrasound technology in placing CPNB in a combat-injured soldier, whose injuries precluded other CPNB options.

Continuous peripheral nerve block in combat casualties receiving low-molecular weight heparin.

BACKGROUND: Continuous peripheral nerve block (CPNB) is an important therapeutic tool in the anaesthetic and analgesic management of combat casualties at Walter Reed Army Medical Center (WRAMC). We describe our experience using CPNB techniques in combat trauma patients treated with low-molecular weight heparin (LMWH). Guidelines used at our institution for managing CPNB catheters in patients being treated with LMWH are introduced. METHODS: From March 2003 to April 2005, 187 combat casualties treated by the WRAMC regional anaesthesia/acute pain section using CPNB were evaluated retrospectively by electronic chart review. Patient characteristic data, CPNB type, duration of CPNB, indication for LMWH [enoxaparin sodium injection (Lovenox-Sanofi Aventis, Bridgewater, NJ, USA)], enoxaparin dose (mg) before and after catheter insertion and removal, time from CPNB placement and removal to enoxaparin dose, and complications were recorded. RESULTS: Median enoxaparin dose and time given before catheter insertion were 30 mg and 21 h, respectively. Median enoxaparin dose was also 30 mg given a median of 12 h after peripheral nerve catheter placement. Catheters remained in situ for a median of 8 days (range 1-33 days). Catheter specific complications were infrequent and identified in 7 (3.7%) patients (two catheter malfunction-kinking, catheter tip dislodgement in situ, two superficial catheter site infections and two catheter dislocations). There were no catheter-related bleeding complications evident in this study. CONCLUSIONS: Information regarding the safety of CPNB in patients treated with LMWH for perioperative venous thromboembolism prevention is scarce. Our initial experience with CPNB and concurrent LMWH has not been complicated by catheter-related bleeding.

Ambulatory surgery with long acting regional anesthesia.

Ambulatory surgery has grown dramatically in the past 3 decades; however, advances in postoperative pain treatment have not kept pace with the proliferation of outpatient procedures. Two techniques that may offer a solution to part of this problem are long acting peripheral nerve blocks (PNB) and outpatient continuous peripheral nerve blocks (CPNB), but the safety of sending patients home with blocked extremities has also remained controversial. Unfortunately, only a few large, prospective studies have examined this issue directly. Those that have addressed this particular question support the concept that regional anesthesia and discharge with an insensate limb may be done safely. Our group prospectively studied 2,382 long-acting PNB with ropivacaine in both the upper and lower extremity noting a low incidence of block failure, rare use of opioids in the recovery unit and high patient satisfaction. This study also demonstrated a low incidence of accidental injury to the blocked extremity and a rare block complication rate after discharge (0.2%). Only 1 patient in this data set fell while exiting a car. Patients in our study appeared to uniformly protect themselves from further injury despite having a blocked extremity. In conclusion, PNB and perineural catheter techniques are an exciting aspect of ambulatory anesthesia and acute pain management that has undergone rapid development in recent years. Successful application of these techniques will require a substantial educational investment by anesthesiologists and anesthesiologists in training. The rewards in reduced postoperative pain, improved patient satisfaction, and anesthesiologist professional development make this endeavor worthy of our attention.

Effects of ethanol and acetaldehyde on cultured pre-implantation mouse embryos.

Pre-implantation 2-cell stage mouse embryos, obtained from superovulated CF-1 mice, were exposed to ethanol and acetaldehyde through the culture medium for 60 min followed by a 105-h incubation period. Control and ethanol exposed embryos survived equally well in ethanol concentrations as high as 800 mg/100 ml medium and acetaldehyde levels up to 10 mg/100 ml medium.

Bilateral continuous paravertebral catheters for reduction mammoplasty.

Surgical procedures of the breast can result in significant postoperative pain. Paravertebral nerve blocks have been used successfully in the management of analgesia after breast surgery but are limited by a single injection. This report describes the use of bilateral paravertebral catheters to provide extended analgesia for reduction mammoplasty. A 48-year-old female underwent bilateral paravertebral catheter placement at thoracic level 3 and local anesthetic injections followed by general anesthesia for elective reduction mammoplasty. She reported no pain following the operation and required no supplemental opioids for pain management during her overnight recovery. This case demonstrates a method for extended bilateral thoracic analgesia. The technique may offer an alternative to traditional outpatient analgesics for reduction mammoplasty.