The effect of vascular access location and size on circuit survival in pediatric continuous renal replacement therapy: a report from the PPCRRT registry.

PURPOSE: Well-functioning vascular access is essential for the provision of adequate CRRT. However, few data exist to describe the effect of catheter size or location on CRRT performance in the pediatric population. METHODS: Data for vascular access site, size, and location, as well as type of anticoagulant used and patient demographic data were gathered from the ppCRRT registry. Kaplan-Meier curves were generated and then analyzed by log-rank test or Cox Proportional Hazards model. RESULTS: Access diameter was found to significantly affect circuit survival. None of the 5 French catheters lasted longer than 20 hours. Seven and 9 French, but not 8 French, catheters fared worse than larger diameter catheters (p=0.002). Circuits associated with internal jugular access survived longer than subclavian or femoral access associated circuits (p<0.05). Circuit survival was also found to be favorably associated with the CVVHD modality (p<0.001). CONCLUSIONS: Functional CRRT circuit survival in children is favored by larger catheter diameter, internal jugular vein insertion site and CVVHD. For patients requiring catheter diameters less than 10 French, CRRT circuit survival might be optimized if internal jugular vein insertion is feasible. Conversely, when a vascular access site other than the internal jugular vein is most prudent, consideration should be given to using the largest diameter catheter appropriate for the size of the child. The CVVHD modality was associated with longer circuit survival, but the mechanism by which this occurs is unclear.

Comparison of intradermal and subcutaneous injections in lymphatic mapping.

BACKGROUND: Sentinel node biopsy (SNB) for melanoma, with its intradermal (ID) injection, has a higher success rate than SNB for breast cancer, which is typically performed with a subcutaneous (SC) or peritumor injection. It is hypothesized that this is in part due to a slower transit time of lymphatic mapping agents through the parenchymal lymphatics of the breast. No study has investigated differences in transit time between different tissues to account for this clinical observation. The goal of the study was to compare transit time between ID and SC injections with common agents used in lymphatic mapping. METHODS: Four injection sites on five domestic pigs were used. Sites were bilateral and included cervical, forelimb, hindlimb, and flank areas. Agents included technetium sulfur colloid (Tc99, filtered and unfiltered), isosulfan blue (IB) dye, and fluorescein (FL) dye. At each site both ID and SC injections were made and the transit time to reach the sentinel node was recorded. The transit time differences were calculated per centimeter distance from the draining lymph node basin. RESULTS: Sentinel nodes were identified draining all sites and found to be hot, blue, or fluorescent (using a Wood's lamp for identification). The cervical and forelimb injection sites drained to the same cervical lymph node basin and both SC and ID injection sites drained to the same sentinel node. Similarly, the hindlimb and flank injection sites both drained to inguinal lymph node basins. The slowest transit time occurred with Tc99 injected SC and the fastest occurred with Tc99 injected ID, whereas both FL dye and IB traveled rapidly to the sentinel node whether injected SC or ID. Large differences were found using unfiltered Tc99 depending on its injection ID (2.7 s/cm +/- 0.5) vs SC (249 s/cm +/- 14.7, P = 0.008). CONCLUSIONS: Tc99 ID injections were significantly faster than SC injection. The slowest and fastest SC injection agents were unfiltered Tc99 and IB, respectively. Dermal injections provide faster transit of lymphatic agents and may improve the identification rate when applied to patients with breast cancer.

Multicenter trial of sentinel node biopsy for breast cancer using both technetium sulfur colloid and isosulfan blue dye.

OBJECTIVE: To determine the factors associated with false-negative results on sentinel node biopsy and sentinel node localization (identification rate) in patients with breast cancer enrolled in a multicenter trial using a combination technique of isosulfan blue with technetium sulfur colloid (Tc99). SUMMARY BACKGROUND DATA: Sentinel node biopsy is a diagnostic test used to detect breast cancer metastases. To test the reliability of this method, a complete lymph node dissection must be performed to determine the false-negative rate. Single-institution series have reported excellent results, although one multicenter trial reported a false-negative rate as high as 29% using radioisotope alone. A multicenter trial was initiated to test combined use of Tc99 and isosulfan blue. METHODS: Investigators (both private-practice and academic surgeons) were recruited after attending a course on the technique of sentinel node biopsy. No investigator participated in a learning trial before entering patients. Tc99 and isosulfan blue were injected into the peritumoral region. RESULTS: Five hundred twenty-nine patients underwent 535 sentinel node biopsy procedures for an overall identification rate in finding a sentinel node of 87% and a false-negative rate of 13%. The identification rate increased and the false-negative rate decreased to 90% and 4.3%, respectively, after investigators had performed more than 30 cases. Univariate analysis of tumor showed the poorest success rate with older patients and inexperienced surgeons. Multivariate analysis identified both age and experience as independent predictors of failure. However, with older patients, inexperienced surgeons, and patients with five or more metastatic axillary nodes, the false-negative rate was consistently greater. CONCLUSIONS: This multicenter trial, from both private practice and academic institutions, is an excellent indicator of the general utility of sentinel node biopsy. It establishes the factors that play an important role (patient age, surgical experience, tumor location) and those that are irrelevant (prior surgery, tumor size, Tc99 timing). This widens the applicability of the technique and identifies factors that require further investigation.

Anterior thoracotomy wound complications in minimally invasive direct coronary artery bypass.

BACKGROUND: The minimally invasive anterior thoracotomy for beating heart coronary bypass offers a modest 10-cm incision and avoids the morbidity of extracorporeal circulation. This study examines minimally invasive direct coronary artery bypass (MIDCAB) wound complications and contributing comorbid factors. METHODS: A retrospective, single-institution review of 165 consecutive MIDCAB cases performed between March 1996 and August 1999 examined all wound abnormalities. Two surgeons performed all cases. RESULTS: Wound complications occurred in 15 patients (9.1%), including three (1.8%) incisional hernias, four (2.4%) superficial dehiscences, three (1.8%) wound infections, three (1.8%) chronic pain syndromes, and two (1.2%) seromas. Two patients with incisional hernias required operative repair. The remaining wound abnormalities responded to conservative therapy. Two chronic pain syndrome cases resolved spontaneously, but the third required advanced pain management. In contrast to MIDCAB, the sternotomy wound complications proved significantly less prevalent (n = 5259, 1.1% vs 9.1%, p < 0.005). CONCLUSIONS: Although MIDCAB offers several advantages over standard approaches, these data suggest that anterior thoracotomy wound complications are not insignificant and may be underestimated by those exploring minimally invasive options.

Filtered versus unfiltered technetium sulfur colloid in lymphatic mapping: a significant variable in a pig model.

BACKGROUND: Lymphatic mapping with sentinel node biopsy is becoming a standard diagnostic test for melanoma and is being extensively investigated for use with other soft tissue tumors. Both filtered and unfiltered technetium sulfur colloid (Tc 99) have been used for preoperative lymphoscintigraphy, as well as intraoperative lymphatic mapping, and it is not clear if one is preferable over the other. The purpose of this study was to compare these two preparations to determine whether the form of Tc 99 used affects the results of lymphatic mapping. METHODS: Mock skin sites were placed on each extremity of 12 domestic pigs totaling 48 skin sites. Twenty-four of the lesions were injected with unfiltered Tc 99; the remaining 24 were injected with Tc 99 passed over a 0.2-microm filter. Both preparations of Tc 99 were mixed with 1 mL of isosulfan blue before injection. Sentinel node dissection was performed using a gamma probe, with counts recorded over a 10-second period and timed to begin 5 minutes after injection. RESULTS: Sentinel nodes were identified in all 48 lymph node basins draining the mock sites and characterized as hot (10x background), blue, or both. Significantly more sentinel nodes were found in the filtered (105 total, X = 4.4/basin), than in the unfiltered group (total 53, X = 2.2/basin, P <.0001). The filtered group had both a higher number of nodes that were hot (35 vs. 6) and more nodes that were hot and blue (69 vs. 43). In addition, hot secondary level lymph nodes (iliac and deep cervical) were found in 11 of 24 of the basins (46%) in the filtered group compared to 1 of 24 (4%) in the unfiltered group (P <.003). There was no significant difference in injection site or residual basin counts between the two groups, but in vivo counts over the sentinel node sites were significantly lower in the unfiltered group (X = 2670+/-1829 vs. X = 6027+/-4333; P = .003). CONCLUSION: Use of filtered Tc 99 results in more sentinel nodes (both hot/blue and hot non-blue) and a higher proportion of secondary lymph nodes. These findings indicate that the Tc 99 preparation used is a significant variable in the results of lymphatic mapping. It is critical that future clinical studies document which preparation of Tc 99 was used. Only large clinical trials will be able to determine whether the additional nodes found with filtered Tc 99 increase the sensitivity of the technique or merely increase the number of nodes that must be removed unnecessarily.