Biomedical subjects

Louis Rivera

Publications and source records attributed to Louis Rivera.

5 recordsLinked to original sources

PubMed2006

Computed tomography-based clinical diagnostic pathway for acute appendicitis: prospective validation.

BACKGROUND: Despite our regular use of CT for suspected appendicitis, a recent study at our institution demonstrated a negative appendectomy (NA) rate similar to our rate 15 years earlier. Based on analysis of this data, a diagnostic pathway was implemented prospectively for adult patients with possible appendicitis. STUDY DESIGN: Rates of CT, NA, and perforation for nonpregnant patients over 14 years of age undergoing appendectomy between August 2001 and August 2002 (PRE) were compared with prospectively collected pathway data (PATH, August 2004 to August 2005). All PATH patients were evaluated by a surgeon before CT. All females underwent CT. CT was obtained in male patients with low suspicion or pain for longer than 48 hours. After negative CT, patients were discharged from the emergency department or admitted for observation. RESULTS: There was a substantial decrease in NA rate after implementation of the pathway (4% PATH [8 of 183] versus 16% PRE [31 of 196], p < 0.001), without a change in the rate of perforation (11% PATH [20 of 175] versus 8% PRE [13 of 165], p = 0.28) or frequency of preoperative CT (59% PATH [108 of 183] versus 60% PRE [118 of 196], p = 0.84). CONCLUSIONS: Frequent appendiceal CT alone does not ensure surgical diagnostic accuracy. CT need not be used in all patients to achieve very low NA rates. An evidence-based diagnostic algorithm incorporating early surgical evaluation, objective criteria for preoperative CT, deterrence of early operation after negative CT, and use of CT to facilitate safe discharge led to substantial improvements in the care of our adult population presenting with possible appendicitis.

Acute Disease↗

PubMed2006

Hepatic intra-arterial infusion of yttrium-90 microspheres in the treatment of recurrent hepatocellular carcinoma after liver transplantation: a case report.

Hepatocellular carcinoma (HCC) recurs with a reported frequency of 12%-18% after liver transplantation. Recurrence is associated with a mortality rate exceeding 75%. Approximately one-third of recurrences develop in the transplanted liver and are therefore amenable to local therapy. A variety of treatment modalities have been reported including resection, transarterial chemo-embolization (TACE), radiofrequency ablation (RFA), ethanol ablation, cryoablation, and external beam irradiation. Goals of treatment are tumor control and the minimization of toxic effect to functional parenchyma. Efficacy of treatment is mitigated by the need for ongoing immunosuppression. Yttrium-90 microspheres have been used as a treatment modality both for primary HCC and for pre-transplant management of HCC with promising results. Twenty-two months after liver transplantation for hepatitis C cirrhosis complicated by HCC, a 42-year old man developed recurrence of HCC in his transplant allograft. Treatment of multiple right lobe lesions with anatomic resection and adjuvant chemotherapy was unsuccessful. Multifocal recurrence in the remaining liver allograft was treated with hepatic intra-arterial infusion of yttrium-90 microspheres (SIR-Spheres, Sirtex Medical Inc., Lake Forest, IL, USA). Efficacy was demonstrated by tumor necrosis on imaging and a decrease in alpha-fetoprotein (AFP) level. There were no adverse consequences of initial treatment.

Adult↗

PubMed2006

Abdominal computed tomography for postoperative abscess: is it useful during the first week?

While classic teaching dictates computed tomography (CT) for postoperative abdominal or pelvic abscess in the first week is of low yield, little evidence supports intentional delays in imaging for suspected abscess. This retrospective review examined all CT scans obtained for clinical suspicion of abscess between 3 and 30 days after abdominal or pelvic operation over a 3-year period. Scans were grouped into those obtained between 3 and 7 days after surgery (EARLY) and those obtained after day 7 (LATE). Diagnostic yield was compared between EARLY and LATE groups. Of 262 CT examinations (EARLY, n = 106; LATE, n = 156), 71 studies (27%) demonstrated abscess. There was no significant difference in the diagnostic yield of CT for abscess between EARLY and LATE groups (23% [24 of 106] versus 30% [47 of 156], P = 0.18). Of patients with an abscess, 63% (45 of 71) underwent percutaneous or operative drainage (EARLY 75% [18 of 24], LATE 57% [27 of 47], P = 0.15). Abdominal CT for postoperative abscess can be expected to be diagnostic in a substantial proportion of cases in the first week, the majority of which lead to percutaneous or operative drainage. Postoperative CT for intra-abdominal abscess should be obtained as clinically indicated, regardless of interval from surgery.

Abdominal Abscess↗

PubMed2006

Retrievable vena cava filters for preventing pulmonary embolism in trauma patients: a cautionary tale.

BACKGROUND: Retrievable vena cava filters (RFs) offer the appeal of short-term prophylaxis for trauma patients temporarily at risk for pulmonary embolism (PE) without the long-term risks of permanent vena cava filters (PFs). However, the evidence that RFs and PFs reduce the risks of PE and death in trauma patients is not conclusive. RFs were introduced at our trauma center in August 2002. The purpose of this study was to evaluate the effects of RFs on our strategy to prevent PE in trauma patients. METHODS: We reviewed our trauma registry to compare rates of filter placement, filter-related complications (FRCs), and PE before (Group I: January 2000 to August 15, 2002) and after (Group II: August 16, 2002 through December 2004) RF introduction. Indication for filter placement, filter retrieval, FRCs, and incidence of PE were compared. RESULTS: There were 5,042 patients in Group I and 5,038 patients in Group II. There was a threefold increase in filter placement in Group II compared with Group I (55 [1.1%] versus 161 [3.2%]; p < 0.001). There were no significant differences between the rates of PE (0.2% versus 0.2%, p = 0.636) or major FRCs (1.8% versus 2.5%, p = 0.777). Major FRCs included two filter infections with sepsis, one vena cava thrombotic occlusion, one filter lodged in the jugular vein during retrieval, and one PE after filter placement. RF removal was attempted in 43 (27%) patients and successful in 33 (21%). CONCLUSION: The advent of RFs was associated with a threefold increase in vena cava filter placement in our trauma center. Major FRCs were encountered and a very low incidence of PE was not altered by their use. Successful removal could be verified in only 21% of RFs. The results of this study lead us to question the rationale for a more liberal use of vena cava filters in trauma patients.

Adult↗

PubMed2004

The influence of age and gender on the utility of computed tomography to diagnose acute appendicitis.

Few studies have examined the effects of age and gender on the utility of diagnostic computed tomography (CT) for appendicitis. We retrospectively studied all adult patients undergoing appendectomy from January 2000 through December 2002 (633 patients). Patients 15-30 years old ("younger") were compared to patients >30 ("older") and further subdivided by gender. CT accuracy and the influence of CT on negative appendectomy (NA) rates for each group were evaluated. CT was associated with a lower NA rate in older patients (23% vs 8%, P = 0.004) but had no effect on NA rate in younger patients (26% vs 20%, P = 0.2). Appendiceal CT had greater sensitivity, negative predictive value, and accuracy in older than in younger patients. When subdivided by gender, CT was associated with lower NA rates for all female patients but had no effect in either age group of men. Although CT may be more accurate in patients older than 30 years, it has the greatest benefit in female patients, where it is associated with lower NA rates in all adult patients. CT should be strongly considered for all female patients before operation for suspected appendicitis. Further study is needed to determine which, if any, male patients benefit from preoperative CT.

Acute Disease↗