John H. Crabtree

Effective use of laparoscopy for long-term peritoneal dialysis access

BACKGROUNDnLaparoscopy is an underused modality for peritoneal dialysis access procedures. The strengths of laparoscopy are that it can both prevent and resolve the common mechanical problems that adversely effect dialysis catheter outcomes.nnnMETHODnLaparoscopically enabled catheter implantation and rescue procedures included rectus sheath catheter tunneling, omentopexy, adhesiolysis, resection of epiploic appendices, colopexy, salpingectomy, and appendectomy. Using these techniques, the outcomes of 428 laparoscopically implanted catheters were studied.nnnRESULTSnDuring a mean follow-up of 21.6 months, mechanical obstruction complicated 3.7% of implantation procedures. The incidence of pericatheter leak was 2.6%. There were no occurrences of pericatheter hernia or subcutaneous cuff extrusion. Laparoscopic salvage procedures limited losses from mechanical catheter problems to .9%. Cumulative revision-free and assisted catheter survival probabilities for loss from mechanical complications at 5 years were .96 and .99, respectively.nnnCOMMENTSnBecause it is enabled by techniques not available to other catheter-placement methods, laparoscopy produces superior outcomes.

The effect of occlusive dressings on the energy metabolism of severely burned children.

Metabolic studies were performed on 23 burned children. They were studied sequentially until their burn wounds were healed. A metabolic study lasted 20 minutes, during which continuous measurements were made of O2 consumption and CO2 production rates, rectal temperature, average surface temperatures (dressings, skin and wound), body heat content, and rate of body weight loss using a bed scale. These measurements allowed solution of the heat balance equation for each study period. After 24 hours in a constant temperature room kept at 28 C and 40% relative humidity, metabolic studies were initiated when blood was drawn for catecholamine assay, followed by a metabolic analyses, after which dressings were removed and fresh silvadene applied to the wounds. No dressings were applied. Metabolic analyses were repeated after two and four hours of exposure, after which blood for catecholamine analysis was drawn and the study terminated. Without dressings in a thermally neutral environment, burn patients demonstrated an increased rate of heat loss of 27 watts/square meter body surface area (W/M2), compared with the predicted normal. The major portion of this increment is by evaporation, which increased 300%. The rate of heat production equals heat loss, and is increased 50% above the predicted normal. Occlusive dressings result in a 15 W/M2 decrease in the rate of heat loss, about evenly divided between evaporative and dry routes, with a corresponding 15 W/M2 decrease in the rate of heat production. Plasma catecholamine levels of bandaged burn patients are not significantly different from values for healed burn patients, and do not correlate with the rate of heat production. The increased heat production of burn patients is a response to an increased rate of heat loss, not vice versa. The use of occlusive dressings substantially reduces the energy requirements to manageable levels, even in patients with very large burns.

WHO SHOULD PLACE PERITONEAL DIALYSIS CATHETERS

♦ Background: Nephrologists are often thwarted in their attempts to grow their peritoneal dialysis programs because of suboptimal surgeon performance in placing catheters. A rallying call is heard among nephrologists to step up to the role of dialysis access providers. ♦ Objective: What factors influence the practicability of nephrologists becoming primary dialysis access providers? Why have surgeons failed their task and can anything motivate them to change their performance and improve outcomes? ♦ Methods: While the issues are universal, this analysis focuses on current practice data from the United States. Evidence reviewed includes dialysis center size and annual new starts, profile of specialties performing catheter placement, nephrology workforce capacity, catheter implantation methodology, resource utilization for peritoneal access, and surgeon performance. ♦ Results: The current nephrology workforce is running at maximum capacity and fellowship training programs will struggle to meet additional demands. Nephrology training programs are often deficient in providing adequate experience in peritoneal dialysis management. Only 2.3% of peritoneal catheters are placed by nephrologists. The best catheter outcomes are produced by laparoscopic methods used by surgeons. Compared to other catheter placement techniques, laparoscopy enables a larger candidate pool of patients. Nonetheless, suboptimal surgical performances are related to inadequate training, low procedure volume, and poor reimbursement. ♦ Conclusions: It is improbable that nephrologists can expand the scope of their practice to assume the additional role of dialysis access providers. The performance of the existing surgical workforce can be enhanced through medical society-sponsored educational activities, channeling access procedures to designated surgeons, and improved remuneration through outcomes-based incentive programs.

Long-term experience with polyurethane, pail handle, coiled tip peritoneal dialysis catheters.

Long-term experience with 63 polyurethane, pail handle, coiled tip peritoneal dialysis catheters surgically implanted in 57 consecutive patients with renal failure is presented. One hundred percent follow-up of the study group represented 1,248 patient-months of observation. Cumulative catheter survival rates were 80.8% at 12 months, 62.3% at 24 months, and 48.1 % through 51 months. Catheter half-life was 32.6 months. Infection was the most frequent catheter related complication. Incidence rate of peritonitis was 0.73, and exit site/tunnel infection was 0.42 episodes per patient-year. Median time to first episode was 11.7 months for peritonitis, and 26.3 months for exit she/tunnel infection. Infection led to removal of 28.6% of implanted devices, mechanical blockage resulted in 6.4% loss, and pericatheter leak and tubing break each accounted for 1.6% of catheter removals. The polyurethane, pail handle, coiled tip peritoneal catheter was found to be a reliable long-term access device compared with reported performances of other catheter types. An adverse outcome was identified in the current clinical series with a model design using a permanently attached catheter adapter that caused large exit site wounds that were predisposed to infection and catheter loss. ASAIO Journal 1998; 44309–313.

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.

Peritoneal dialysis catheter embedment: surgical considerations, expectations, and complications

BACKGROUNDnPeritoneal dialysis catheter embedment consists of implanting the catheter far in advance of anticipated need, with the external tubing buried under the skin. The catheter is externalized when initiation of dialysis is required. Details of the surgical procedure and management of associated complications are generally lacking.nnnMETHODSnA total of 84 catheters including conventional and extended catheters were embedded and externalized during the study period. Factors influencing duration of embedment, functionality upon externalization, and long-term outcomes were analyzed.nnnRESULTSnMean duration of embedment was 13.9 months (median 9.4; range .5 to 68.5). Immediate function was exhibited in 85.7% of catheters. Employing laparoscopic revision, 98.8% of embedded catheters were successfully used for peritoneal dialysis. Extended catheters and duration of embedment were important determinants of catheter functionality.nnnCONCLUSIONSnCatheters can be embedded for prolonged periods and still result in functional dialysis access when needed. Complications are few and easily managed.

Energy metabolism in anesthetized children with burns

Abstract Energy dynamics in 10 burned children were studied to determine cause and effect relationships between rates of heat production, heat loss and plasma catecholamine concentrations when thermoregulatory responses were depressed by methoxyflurane anesthesia. Rapid cooling of the burned children was due to increased heat loss during the period of anesthesia. Heat production increased significantly, although not enough to counterbalance the increased heat loss reflecting a block in central thermoregulation by general anesthesia. Mean plasma catecholamine concentrations decreased during general anesthesia as compared with baseline values. Heat production attempted to track heat loss during a period in which plasma catecholamine levels declined. An increased rate of heat loss is concluded to be the primary stimulus for increased metabolic activity after thermal injury.

Is the Tenckhoff catheter still the first choice for use with peritoneal dialysis

The designation, ‘‘Tenckhoff catheter’’, is analogous to the phenomenon of a brand name gone generic, more familiar examples being Kleenex for facial tissues, Frigidaire for refrigerators, and Coke for colas. No current versions of Tenckhoff’s peritoneal access device possess the originally described dimensions, which also included straight tip and coiled tip styles (1). For the purpose of this essay, a Tenckhoff catheter will be taken as a silicone rubber tube having a straight or coiled intraperitoneal tip, equipped with two or more cylindrical Dacron cuffs, possessing either a straight or preformed tubing bend in the intercuff segment and optionally allowing extension of the subcutaneous segment with an additional component of attached silicone rubber tubing to enable exit-site locations away from the usual lower abdominal region (Fig. 1). This definition is sufficient to separate the Tenckhoff catheter from a variety of devices comprised of such features as an intraperitoneal disk tip, tungsten weighted tip, fluted tubing, or angled anchoring beadflange (Fig. 2). This commentary ignores designs intended for continuous flow dialysis. Alternatives to Tenckhoff’s general design were created to address problems of catheter flow dysfunction that result from catheter tip migration and tissue attachment. Disappointingly, none of these imaginative conceptions have improved outcomes over that of the generic Tenckhoff catheter. While resources have been lopsidedly directed toward device development, much less attention has been paid to modifications of the catheter insertion procedure that might improve outcomes. Indeed, it turns out that common catheter problems are more reliably addressed by implantation technique than by expensive, complicated, and sometimes compromised catheter designs. Moreover, a catheter design can never compensate for a poorly performed implantation procedure. An effective method of minimizing catheter tip migration takes advantage of the natural toughness and craniocaudal direction of the rectus sheath fascial envelope. Laparoscopy is utilized to guide the implantation of the catheter tubing through a long rectus sheath tunnel in its passage to the peritoneal cavity. The craniocaudal immobilization of the catheter in the rectus muscle and sheath not only maintains a pelvic position of the catheter tip but reduces the risk of pericatheter leakage and eliminates pericatheter hernias. While several methods have been described to laparoscopically guide placement of a catheter into a rectus sheath tunnel, the use of bladeless laparoscopic port systems facilitate this maneuver in a simple, safe, accurate, and reproducible fashion (2,3). Attempts to simulate this craniocaudal catheter configuration by laparoscopically suturing the catheter to the abdominal wall or pelvis increases the invasiveness of the procedure, will not prevent catheter tip migration if the suture fails, can potentially complicate catheter removal if the suture holds, and does nothing to reduce the risk of pericatheter leak and hernia. Partial or complete catheter obstruction or displacement of the catheter to a position of suboptimal drainage is usually produced by omental entrapment. Catheter obstruction by an omental wrap represents the most common mechanical complication causing catheter loss following conventional catheter placement methods. Prophylactic resection of the omentum at the time of catheter implantation has been utilized in an attempt to prevent catheter obstruction. An alternative to omental resection is laparoscopic omentopexy, an omental

Simultaneous Catheter Replacement for Infectious and Mechanical Complications Without Interruption of Peritoneal Dialysis.

♦ Background: Conventional management for peritoneal dialysis (PD)-related infectious and mechanical complications that fails treatment includes catheter removal and hemodialysis (HD) via a central venous catheter with the end result that the majority of patients will not return to PD. Simultaneous catheter replacement (SCR) can retain patients on PD by avoiding the scenario of staged removal and reinsertion of catheters. The aim of this study was to evaluate a protocol for SCR without interruption of PD. ♦ Methods: Clinical outcomes were analyzed for 55 consecutive SCRs performed from 2002 through 2012 and followed through 2013. ♦ Results: Simultaneous catheter replacements were performed for 28 cases of relapsing peritonitis, 12 cases of tunnel infection, and 15 cases of mechanical catheter complications. All cases for peritonitis and tunnel infection and 80% for mechanical complications continued PD on the day of surgery using a low-volume, intermittent automated PD protocol. Systemic antibiotics were continued for 2 weeks postoperatively (up to 4 weeks for Pseudomonas). Simultaneous catheter replacement was performed as an outpatient procedure in 89.1% of cases. Only 1 of 55 procedures was complicated by peritonitis within 8 weeks. No catheter losses occurred during this postoperative timeframe. Long-term, SCR enabled a median technique survival of 5.1 years. ♦ Conclusions: In most instances, SCR can be safely performed without interruption of PD for selected cases of peritonitis and tunnel infection and for mechanical catheter complications. The procedure spares the patient from a central venous catheter, a shift to HD, the psychological ordeal of a change in dialysis modality, and a second surgery to insert a new catheter.

Embedded Catheters: Minimizing Excessive Embedment Time and Futile Placement while Maintaining Procedure Benefits

♦ Background: Embedding peritoneal catheters far in advance of anticipated need may successfully commit patients to their modality choice and reduce central venous catheter use but can be complicated by excessive embedment periods and futile catheter placement. ♦ Objective: Embedded catheter outcomes were studied to identify factors that minimize inordinate embedment time and futile placement while maintaining procedure benefits. ♦ Methods: Clinical and laboratory data were examined in 107 patients with embedded catheters that were either externalized, remained embedded, or were futilely placed. ♦ Results: Externalization of 84 catheters was performed after a median embedment period of 9.4 months. Flow dysfunction occurred in 14.3% of externalized catheters. Overall function rate was 98.8% after laparoscopic revision. One patient changed their mind about modality choice. Except for 1 patient hospitalized acutely in a facility unfamiliar with embedded catheters, none remaining on a peritoneal dialysis pathway initiated dialysis with a central venous catheter. Including catheters with extremely long embedment periods, the incidence of futile placement was 13.1%. Multiple regression analysis identified estimated glomerular filtration rate (eGFR) and serum albumin as the 2 variables best associated with catheter embedment duration (r2 = 0.44, p < 0.0001). Diabetic nephropathy was statistically more likely to be associated with lower serum albumin values (p < 0.0001); however, no association was noted between diabetic status and embedment duration (p = 0.62). ♦ Conclusions: Timing of the embedment procedure should include appraisal of both eGFR and serum albumin. Appropriate consideration of these values together may help minimize excessive embedment periods and decrease futile placements while preserving procedure benefits.