Magnetically guided nasoenteral feeding tubes: a new technique.

Our objective was to evaluate a new technique for the bedside placement of nasoenteral feeding tubes into the duodenum using an external hand-held magnet to maneuver the tube from the stomach to the distal duodenum. We conducted a prospective case series of 20 consecutive patients requiring nasoenteral tube feeding in the intensive care units of a university-affiliated hospital. Twenty patients were entered into the study after the attending physician requested assistance in tube placement. A flexible nasoenteral feeding tube (12 F), modified to include a magnet and a magnetic field sensor in the distal tip connected by a thin insulated wire to a small light at the proximal end, was passed per nares into the stomach. A larger hand-held magnet held over the epigastrium was used to magnetically "capture" the tube tip, indicated by the illumination of the proximal light. The tube tip was then maneuvered by the hand-held magnet along the lesser curvature of the stomach, through the pylorus, and into the duodenum. Procedure time and anatomic location of the tube tip as determined by an abdominal radiograph was recorded. The 12 men and eight women had a mean age of 60 years (range 30-84). The procedure time averaged 9.6 minutes (range 1-30). In 19 of the 20 patients (95%) radiographs revealed successful placement of the tip of the feeding tube into the duodenum. There were no complications related to the procedure. Using a novel magnetically guided nasoenteral feeding tube transpyloric tube placement was achieved in 95 per cent of cases with an average procedure time of 9.6 minutes. This new and inexpensive bedside technique will allow prompt and safe initiation of enteral nutrition.

Delayed vaccination does not improve antibody responses in splenectomized rats experiencing hypovolemic shock.

Delayed vaccination after splenectomy has been shown to increase the antibody response in normotensive rats. The purpose of this experiment was to study the effect of timing of vaccination on antibody responses in rats undergoing splenectomy and experiencing hypovolemic shock. Sixty male Sprague-Dawley rats weighing 250 to 400 g underwent either a sham abdominal surgery or splenectomy after a 30-minute period of controlled hypovolemic shock. All rats then received pneumococcal vaccinations one day, 7 days, or 28 days postoperatively. Antibody levels were determined by enzyme-linked immunosorbent assay 3 weeks after vaccination. Results were compared by analysis of variance. Animals vaccinated one day postoperatively had similar or higher antibody responses than did rats receiving delayed vaccinations after 7 or 28 days. These results were similar for immunoglobulins G and M and more importantly were consistent for animals undergoing splenectomy and sham operations. Delayed vaccinations failed to improve antibody responses when hypovolemic shock preceded splenectomy. We propose that this is the result of complex cytokine responses to hypovolemic shock. These responses have been studied extensively in the setting of septic shock but not in the setting of hypovolemic or hemorrhagic shock.

Improved antibody responses to delayed pneumococcal vaccination in splenectomized rats.

Pneumococcal vaccination following splenectomy is widely used as prophylaxis against overwhelming postsplenectomy infection. There remains controversy however, over the timing of vaccination. We hypothesized that delaying vaccination would increase the antibody response. Pneumococcal vaccinations were given at designated intervals to rats that had undergone either a sham abdominal surgery or splenectomy. Sixty male Sprague-Dawley rats, 250 to 400 g, were divided into three groups for vaccination: I, 1 day postoperatively; II, 7 days postoperatively; and III, 28 days postsplenectomy/sham. Serum antibody levels were then determined by enzyme-linked immunosorbent assay at 5 and 21 days after vaccination. Immunoglobulin (Ig) levels after delayed vaccination at 1 week postoperatively and 1 month postoperatively were significantly higher than levels from rats vaccinated 1 day postoperatively. IgM levels after vaccinations 1 week and 1 month postoperatively were also significantly higher than levels of rats vaccinated 1 day postoperatively (P < 0.05 for both IgG and IgM). On the basis of these results, we conclude that delaying vaccination after splenectomy enhances antibody responses.

Surgery in nonagenarians: morbidity, mortality, and functional outcome.

BACKGROUND: There are few studies that document the outcomes experienced by very old patients who undergo major surgery. METHODS: This is a case series and 7-year follow-up of 116 consecutive patients who were aged 90 years or older and underwent major surgery at a large university-affiliated community hospital. We describe the functional status, short- and long-term mortality, and predictors of mortality in this group of frail elders. RESULTS: The 116 nonagenarians in this study underwent 134 major operations. Sixty-three patients were admitted to the hospital from a nursing home. The most common surgical procedures were for hip fracture, lower extremity amputation, and abdominal problems. Nineteen patients died in the hospital following surgery, and 23 patients died within 30 days of operation. Follow-up at 7 years revealed that all but three patients had died. Survival was worse for patients admitted from nursing homes, those who were nonambulatory before surgery, and those with major or complete functional impairment. CONCLUSIONS: Major surgery in nonagenarians is associated with a 20% perioperative mortality. Functional status and ambulatory ability are maintained in most patients. Whether to operate on these frail elders is a complex decision.

Accurate deployment of vena cava filters: comparison of intravascular ultrasound and contrast venography.

BACKGROUND: The increasing use of vena cava filters by trauma surgeons has led to reports of filter placement using intravascular ultrasound (IVUS). Although attractive because of its ease of use and elimination of contrast and radiation, no studies have examined the accuracy of filter placement by IVUS as compared with contrast venography (CV). The purpose of this study was to compare the anatomic information obtained by both techniques during filter placement. METHODS: Twenty-one patients meeting trauma service criteria for filter placement were studied (11 women and 10 men; mean age, 46.8 years). All procedures were performed in the operating room by trauma surgeons. Vascular access was obtained by percutaneous placement of an 8 French sheath in the right femoral vein. CV, IVUS, and bilateral selective renal venography were performed before deployment of a Greenfield filter. Localization and diameter measurements were made in reference to a radiopaque ruler placed on the patient's abdomen. We chose the "best location" for filter deployment as 1 cm below the junction of the lowest renal vein and the vena cava. Measurements by CV and IVUS were compared with the "gold standard" of selective renal venography. RESULTS: As compared with selective renal venography, the difference between best location by CV and IVUS was 16.3 +/- 13.8 mm and 3.7 +/- 5.6 mm, respectively (p = 0.001). In four cases (19%) the CV missed best location by 3 cm or more. CV overestimated the diameter of the vena cava in all cases. Average vena cava diameter was 26.4 +/- 3.3 mm by venography and 20.6 +/- 3.1 mm by IVUS (p < 0.0001). CV incorrectly identified four patients as having vena cava diameters too large (>2.8 cm) for the placement of a Greenfield filter. The two renal vein anomalies (one double left renal vein and one absent left renal vein) were correctly diagnosed by IVUS. CONCLUSION: IVUS is a more accurate method of localizing the renal veins and measuring vena cava diameter for placement of vena cava filters than contrast venography.