Posterior tracheal wall perforation during percutaneous dilational tracheostomy: an investigation into its mechanism and prevention.

OBJECTIVES: Part 1: To describe the complication of posterior tracheal wall injury and perforation associated with the percutaneous dilational tracheostomy (PDT). Part 2: To determine the mechanism of posterior tracheal wall injury during PDT. DESIGN: Prospective observational study. SUBJECTS: Part 1: Medical-surgical ICU patients requiring tracheostomy. Part 2: Swine and cadaver models. INTERVENTIONS: Part 1: Consecutive medical-surgical ICU patients undergoing tracheostomy tube insertion via the percutaneous dilation technique with bronchoscopic guidance were enrolled in the study. Demographic data and complications were recorded. Part 2: Tracheostomy tubes were inserted via the percutaneous dilational technique in the swine model with concomitant bronchoscopic video recording from the proximal and distal airways. Tracheostomy tubes were inserted via the percutaneous dilational technique in the cadaver model followed by anatomic inspection of the airway. RESULTS: Part 1: Seven (29%) of 24 medical-surgical ICU patients sustained complications associated with PDT. Three patients (12.5%) sustained posterior tracheal wall perforations followed by the development of tension pneumothoraces. Part 2: The swine model demonstrated that posterior tracheal wall perforation may occur during PDT when the guiding catheter is withdrawn into the dilating catheters. Five-centimeter posterior tracheal wall mucosal lacerations occurred when the guidewire and the guiding catheter were not properly stabilized during PDT. CONCLUSION: Percutaneous dilational tracheostomy was associated with a 29% complication rate in this observational study. Of concern was the high rate (12.5%) of posterior tracheal wall perforation. The swine and cadaver models suggest that posterior tracheal wall injury or perforation may occur if the guidewire and guiding catheter are not properly stabilized. To avoid posterior tracheal wall injury, the guidewire and guiding catheter should be firmly stabilized during PDT.

Skin wound closure in athymic mice with cultured human cells, biopolymers, and growth factors.

Skin wound closure remains a major problem in acute and reconstructive skin grafting after large burns because of limited availability of donor skin. This report evaluates six protocols for preparation in vitro of skin substitutes composed of cultured human cells, biopolymers, and growth factors for wound closure. Full-thickness wounds in athymic mice treated in a single procedure with cultured skin substitutes were compared directly to treatments with murine skin autograft, human skin xenograft, or no graft. Rectilinear planimetry of healed wounds 6 weeks after surgery showed that skin substitutes cultured in serum-free medium, and for 24 hours before surgery in defined medium with basic fibroblast growth factor (100 ng/ml), were not statistically different (p less than 0.05) in size from treatment with human skin xenograft. Acceptance and persistence of skin substitutes cultured in serum-free media were 70% at 6 weeks after surgery, as determined by staining of healed skin with a fluorescein-labeled monoclonal antibody against human HLA-ABC antigens. Ultrastructural examination of wounds with cultured human skin 6 weeks after treatment showed complete basement membrane, including anchoring fibrils, presence of melanocytes and pigment transfer to keratinocytes, and innervation of healed skin adjacent to basement membrane. These findings demonstrate effectiveness of cultured skin substitutes for closure of skin wounds and illustrate important capabilities to modulate the natural processes of wound repair, to increase supply of materials used for wound repair, and to enhance quality of wound healing.

Heterotopic pregnancy presenting as an acute abdomen: a diagnostic masquerader.

Simultaneous intrauterine and extrauterine pregnancy is called heterotopic pregnancy. It is a rare complication of pregnancy, especially in the absence of predisposing factors. It is known to present with a variety of symptoms and signs often leading to a delay in establishing the correct diagnosis. We report the case of a 29-year-old woman, known to be 14 weeks pregnant, presenting with acute abdominal pain. The confirmation of a viable intrauterine pregnancy led to a general surgery consultation. A heterotopic ruptured right ectopic tubal pregnancy was found. Right salpingectomy was performed. The patient recovered uneventfully. The intrauterine pregnancy was not affected. This case illustrates the variable presentation of heterotopic pregnancy and the need for general surgeons to be suspicious of pregnancy related complications, even in the presence of a viable intrauterine pregnancy.

Cyclosporine A for prolonging allograft survival in patients with massive burns.

Cyclosporine A (CsA) immunosuppression was used in three patients with massive burns to prolong skin allograft survival. Cyclosporine A kinetic studies in patients with burns revealed markedly accelerated blood clearance and high variability in drug absorption when compared with studies in renal transplantation patients. Doses required to maintain therapeutic levels varied widely. While patients were receiving adequate maintenance therapy with CsA immunosuppression the allograft was tightly adherent without gross or microscopic rejection and was indistinguishable from autograft. Ultimately, patients' wounds were permanently covered with sequential autografts by recropping limited donor sites. There were not unusual septic complications, although prophylaxis for opportunistic infections was used. The disadvantage of allograft use is its early rejection and obligatory replacement until permanent coverage with autograft can be accomplished. Cyclosporine A can prolong allograft survival and allow autograft coverage from limited donor sites in a sequential fashion. This may lead to increased survival in patients with massive burns.