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Biomedical subjects

John H Crabtree

Publications and source records attributed to John H Crabtree.

13 recordsLinked to original sources
PubMed2005

Surgical salvage of peritoneal dialysis catheters from chronic exit-site and tunnel infections.

BACKGROUND: Chronic exit-site and tunnel infections of the peritoneal dialysis catheter are significant causes of catheter loss. Surgical salvage procedures that can effectively resolve the infection and preserve dialysis are of major importance. METHODS: Thirteen patients with chronic exit-site and tunnel infections underwent surgical salvage consisting of unroofing the tunnel tract and shaving of the superficial catheter cuff. A control group of 138 patients implanted during the same time span as the study group was used for infection rate and survival comparisons. RESULTS: The salvage procedure cured the infection in all patients. No dialysate leaks occurred. Peritoneal dialysis was not interrupted. Surgical salvage provided successful long-term peritoneal dialysis that was equivalent to the cohort dialysis population. CONCLUSION: Surgical salvage by unroofing/cuff shaving is an effective long-term solution for chronic exit-site and tunnel infection.

Case-Control Studies↗
PubMed2005

A laparoscopic method for optimal peritoneal dialysis access.

Both medical benefits to the patient and financial incentives to the health care system exist to increase the use of peritoneal dialysis as renal replacement therapy. Providing long-term peritoneal access free of mechanical dysfunction continues to represent a major challenge to the success of this modality. Variable outcomes result from the lack of standard implantation methodology and failure to address persistent problems associated with current implantation techniques. This prospective case study compared noninfectious procedural complications of three approaches to establish peritoneal dialysis access. The groups consisted of 63 catheters implanted by traditional open dissection, 78 catheters implanted by basic laparoscopy without associated interventions, and 200 catheters implanted by advanced laparoscopic methods including rectus sheath tunneling, selective prophylactic omentopexy, and selective adhesiolysis. Mechanical flow obstruction, the major outcome indicator, followed only 1 of 200 (0.5%) implantation procedures in the advanced group and was significantly better (P < 0.0001) than the open dissection (17.5%) and basic laparoscopic (12.5%) groups. A low rate of pericannular leaks (1.3-2%) was not different for the three groups. One pericannular hernia occurred in the open group. Catheter mechanical dysfunction attributable to the surgical technique can nearly be eliminated through adjunctive procedures made possible only by a laparoscopic approach.

Catheters, Indwelling↗
PubMed2003

Laparoscopic implantation of swan neck presternal peritoneal dialysis catheters.

The swan neck presternal peritoneal dialysis catheter provides an alternative location from which a catheter can exit the skin when an abdominal site is not suitable. The exit site is in the upper anterior chest. The presternal catheter was designed for patients who would not ordinarily be considered for peritoneal dialysis because of body habitus, presence of stomas, or urinary-fecal incontinence. In its original design, the catheter can be implanted only by open dissection. We present a modification of the catheter system and describe an operative technique in which the catheter can be inserted laparoscopically. Eight patients underwent laparoscopic implantation of presternal catheters by this technique. During follow-up ranging from 2.9 to 12.4 months (average, 5.3 months), no instances of catheter dysfunction, leakage around the cannula, hernia, or loss secondary to infection occurred. We foresee greater use of the swan neck presternal peritoneal dialysis catheter once surgeons become more familiar with its ease of insertion and if the device can be made available as a single-package system compatible with laparoscopic implantation.

Catheters, Indwelling↗
PubMed2003

Selective performance of prophylactic omentopexy during laparoscopic implantation of peritoneal dialysis catheters.

Omental entrapment of the peritoneal dialysis catheter remains a common cause of flow dysfunction. Prophylactic omentectomy during catheter implantation is still followed with an incidence of flow obstruction as high as 10%. We describe indications and a technique for selective performance of omentopexy during laparoscopic catheter implantation that resulted in only a 0.7% obstruction rate in 153 consecutive patients as compared with a 12.8% rate in a preceding group of 78 consecutive patients. Laparoscopic omentopexy was performed during 9.2% of implant procedures and only when the omentum was found to extend to the retrovesical space. The procedure is simple, quick, and inexpensive to perform. Employing selective criteria for omentopexy eliminates the performance of unnecessary procedures. Actuarial analysis demonstrates that an operative strategy of selectively performing omentopexy for redundant omentum significantly improves catheter survival free of flow dysfunction (P < 0.0001).

Catheterization, Peripheral↗
PubMedDate not supplied

Clinical biodurability of aliphatic polyether based polyurethanes as peritoneal dialysis catheters.

Thermoplastic polyurethane elastomers are the most important implantable grade polyurethanes in medical applications. An aliphatic polyether based polyurethane, Tecoflex (TF; Thermedics, Inc., Woburn, MA), is used in the construction of a proprietary peritoneal dialysis (PD) catheter. Information is limited regarding the biostability of the TF polymer in the clinical environment as a PD catheter. This report presents the clinical experience regarding the biodurability of 104 catheter implants. The extracorporeal tubing segments of all TF catheters eventually developed aesthetically offensive discoloration, opaqueness, and surface tackiness. Catheter breaks in the external segment occurred in 27% of devices that survived longer than 28 months. Mupirocin ointment at the catheter skin exit site caused swelling and deformity of the TF in one case. Three catheters extruded as a result of Dacron cuffs separating from the tubing wall. Catheters removed for other reasons were frequently found to have loose cuffs, especially if the devices were implanted for several years. Causes and possible mechanisms for observed failures are discussed. The durability of biomaterials used in construction of PD catheters is of vital importance for successful long-term functioning. The TF polymer embodied as a PD catheter represents a mismatch of the material and its mission. Fabrication of PD catheters from higher grade polyurethanes possessing greater biostability should be explored. Silicone rubber appears to remain the most durable material to date for PD catheter construction.

Biocompatible Materials↗
PubMedDate not supplied

Optimal peritoneal dialysis catheter type and exit site location: an anthropometric analysis.

An anthropometric analysis of 200 adult patients was performed to provide better guidance in catheter selection and placement. Height, weight, various abdominal wall measurements, and gender effects were analyzed. Suitability of Tenckhoff catheters with straight and preformed bends in the intercuff segment was evaluated regarding ability to produce deep pelvic position of the catheter tip and ideal exit site location. Conflicts with belt line and with skin creases and folds were recorded. Results showed that abdominal wall measurements varied widely by height and weight. Swan neck catheters with a downwardly directed external limb and exit site were significantly better suited for females (62% versus 27%, p < 0.0001). Tenckhoff catheters with straight intercuff segments with a laterally directed tunnel tract and exit site were significantly better matched to males (78% versus 30%, p < 0.0001). Neither catheter was suitable in 25% of subjects, emphasizing the need for an extended catheter system capable of remotely locating the exit site to the upper abdomen or chest without compromising pelvic position of the catheter tip. Appropriate preoperative evaluation with selection of the best suited catheter should replace the substandard practice of using a pet catheter to fit all patients and rigidly placing the insertion incision at a set location irrespective of body habitus.

Abdomen↗
PubMedDate not supplied

The efficacy of silver-ion implanted catheters in reducing peritoneal dialysis-related infections.

BACKGROUND: Dialysis-related infections are the commonest cause of catheter loss and transfer to hemodialysis. Surface modifications of the catheter that reduce infections are of major importance. OBJECTIVE: The efficacy of silver-ion treated catheters in reducing dialysis-related infections was tested. METHODS: The study design was a prospective, randomized controlled trial. Patients were implanted with either a silver-treated study catheter or a control catheter. Prospective collection of data included infectious complications and catheter survival. RESULTS: The subject groups were comprised of 67 silver-treated catheters and 72 control catheters. Demographic characteristics of the study and control groups were equal. Exit-site infection rates for the study group and control group (0.52 and 0.45 episodes/patient-year of dialysis respectively) were not different by Poisson regression analysis (p > 0.4). Peritonitis rates were identical for the two groups (0.37 episodes/patient-year) and were not different by Poisson analysis (p > 0.9). Antibiotic-free intervals between infections for the study and control groups were not significantly different for exit-site infections (p = 0.58), peritonitis (p = 0.44), or both infections combined (p = 0.47). Actuarial analyses showed no differences between the groups in the probability of remaining free of exit-site infection (p > 0.2) or peritonitis (p > 0.7). Similarly, catheter survival was not significantly different between the groups (p > 0.6). CONCLUSION: Surface modification of catheters with ion beam implantation of silver produced no clinical effect with respect to reducing dialysis-related infections.

Adult↗
PubMedDate not supplied

Heated, humidified CO2 gas is unsatisfactory for awake laparoscopy.

BACKGROUND: The necessity for general anesthesia represents an impediment to using a laparoscopic approach for some procedures that are otherwise performed with the patient under local anesthesia using a conventional open technique. Heating and humidifying the insufflation gas reportedly reduces perioperative pain associated with a CO2 pneumoperitoneum, thus enabling awake laparoscopy. METHODS: Two cases are reported herein of laparoscopy performed with the patient under local anesthesia using heated, humidified CO2 gas for the pneumoperitoneum. RESULTS: Both patients experienced pain with insufflation of heated, humidified CO2 gas of sufficient magnitude that the procedure could not be performed. The CO2 gas was washed out and replaced with helium gas insufflation with complete resolution of pain. The laparoscopic procedures were accomplished without further discomfort with local anesthesia and using a helium gas pneumoperitoneum. CONCLUSIONS: Heated, humidified CO2 gas insufflation does not reduce pain sufficiently to permit satisfactory performance of laparoscopy with local anesthesia, especially when full volume insufflation is required. Cold, dry helium gas produces no pain. The theory that cold, dry insufflation gas is a source of peritoneal pain during laparoscopy needs to be reassessed.

Adult↗
PubMedDate not supplied

Prospective comparison of downward and lateral peritoneal dialysis catheter tunnel-tract and exit-site directions.

OBJECTIVE: Guidelines for optimal peritoneal dialysis access support both downward and lateral exit-site directions. Numerous clinical reports support the superiority of downward exit sites but none substantiate lateral configurations. METHODS: This prospective study compared infectious and mechanical complications between 85 catheters with a preformed arcuate bend to produce a downward exit site and 93 catheters with a straight intercuff segment configured to create a lateral exit site. RESULTS: Kaplan-Meier survivals were not different for time to first exit-site infection (p = 0.62), tunnel infection (p = 0.89), or peritonitis (p = 0.38) for downward and lateral exit-site directions. Poisson regression showed no differences in rates (episodes/patient-year) of exit-site infection (0.26 vs 0.27, p = 0.86), tunnel infection (0.02 vs 0.03, p = 0.79), peritonitis (0.42 vs 0.43, p = 0.87), or catheter loss (0.06 vs 0.09, p = 0.29) for downward and lateral exit sites. Kaplan-Meier analyses of antibiotic-free intervals for exit-site (p = 0.94) and peritonitis infections (p = 0.72) were not different for the two groups. There was one case of catheter tip displacement with flow dysfunction in each group. There were no pericatheter hernias or spontaneous cuff extrusions. Catheter survival between groups was not different (p = 0.20). CONCLUSIONS: Catheter types employing downward and lateral tunnel-tract and exit-site configurations produce equivalent outcomes for infectious and mechanical complications.

Catheter-Related Infections↗