Carl-Eric Lindholm

Blood Flow in the Rabbit Tracheal Mucosa under Normal Conditions and under the Influence of Tracheal Intubation

Isotope la belled microspheres were used to study the capillary blood perfusion of the rabbit tracheal mucosa. Under resting conditions the perfusion was about 0.3 ml/min ® g (i.e. about 60% of the relative cerebral blood flow). Irritation of the tracheal mucosa by an endotracheal tube caused a steep rise in blood flow, tenfold or more. This was probably due to relaxation of the arterioles caused by a release of histamine‐like substances.

Cardiorespiratory Effects of Flexible Fiberoptic Bronchoscopy in Critically III Patients

The flexible fiberoptic bronchoscope is used increasingly often as a multipurpose instrument in critical care medicine. In poor risk patients who need continuous mechanical ventilation, rigid open tube bronchoscopy is a problem. With the flexible fiberoptic bronchoscope, however, diagnostic and therapeutic procedures can be carried out without interruption of ongoing mechanical ventilation. This procedure offers the possibility of bronchoscopy with reduced risk in debilitated patients. However, in these critically ill patients, the cardiopulmonary system is functioning at the borderline of its ability. Therefore, even the small changes in ventilation pattern caused by flexible fiberoptic bronchoscopy (FFB) may in some cases cause dangerous cardiopulmonary distress. For example, changes of intrabronchial pressure, tidal volume, PaO2, PaCO2 and cardiac output may be caused by the procedure. Further, it is of great importance to restrict suction through the instrument to short periods to avoid dangerous alterations in the ventilation perfusion relationship. Since serious complications may occur, it is mandatory that the bronchoscopist be aware of the potential pathophysiologic effects of FFB during mechanical ventilation of critically ill patients.

Flexible fiberoptic bronchoscopy in critical care medicine: Diagnosis, therapy and complications

Flexible fiberoptic bronchoscopy was evaluated in 71 procedures in 55 patients. Two-thirds of these procedures were carried out in patients with ongoing mechanical ventilation as their respiratory failure contraindicated rigid bronchoscopy. A wide variety of important diagnostic information was obtained. FFB caused no mortality or serious complications. Transient tachycardia occurred in several patients, cardiac arrhythmia in two and mediastinal emphysema in one patient. Retained secretions and atelectasis were the indications for 53 FFBs; 43 (81%) of these procedures were successful in improving aeration as evaluated with radiography.

Localized laryngeal amyloidosis: Partial characterization of an amyloid fibril protein al

Amyloid fibrils were extracted from a patient Wr with more than 10 yr history of localized laryngeal amyloidosis. Degraded amyloid fibrils reacted in immunodiffusion with an antiserum against an amyloid protein of immunoglobulin kappa light chain origin, showing a line of identity with a kappa I amyloid protein. The protein Wr had a blocked aminoterminal, previously only reported in lambda chains. Amino acid sequence analysis of a fragment of the protein showed it to be an immunoglobulin light chain protein of V kappa I or V kappa III subgroup. The protein had a few unusual amino acid residues as compared to other kappa light chains. The findings support the view that the fibrils in localized, tumour-like amyloidosis are composed by homogeneous immunoglobulin light chain proteins in the same way as is seen in primary and myeloma associated systemic amyloidosis. It is possible that unusual light chains are over-represented in amyloid fibrils.

Tracheal tube forces on the posterior larynx: Index of laryngeal loading

Most tracheal tubes sold today are arcuate in shape while the human airway is S-shaped. In situ, the tubes exert different forces on the posterior larynx, depending on their stiffness. Laryngeal damage after prolonged intubation is recognized as the result of these forces. The authors tested 8 types of size 8.0 tracheal tubes to determine the magnitude of laryngeal loading in a model approximating the geometry of the human airway. The force each tube exerted on the posterior larynx was measured in conditions simulating both, immediately after intubation and after prolonged intubation of 24 h. The force was converted into an integer number, an index of laryngeal loading, that can be used to compare various types of tracheal tubes. The airway model and test procedure can be utilized by manufactures, designers, and others to provide valuable information on tracheal tube performance and to develop improved tracheal tubes in the future. The results indicate that the polyvinylchloride tubes (PVC) and the silicone rubber tubes had the lowest index of laryngeal loading after long-term conditioning and would be preferable for prolonged intubation. The red rubber tube had the highest index of laryngeal loading after long-term conditioning, yet its stiffness would facilitate intubation.

Transvascular fluid exchange in the tracheal mucosa.

Abstract The fluid balance of the rabbit tracheal mucosa was investigated with the micropuncture technique and the microsphere method was used for blood flow measurements. Under resting control conditions the blood flow was 0.62 ± 0.41 ml/min · g of tissue; it increased to 3.22 ± 1.55 ml/min · g when the trachea was divided by a midline incision and fixed with two clamps for the micropuncture experiments. The hydrostatic pressure in the early part of the capillary was 28 mm Hg, in the middle part 17 mm Hg, and in the late part 14 mm Hg. The pressure in the dense network of sinusoidal submucosal veins was 12 mm Hg. The interstitial pressure was 3–4 mm Hg. The plasma colloid osmotic pressure, as estimated from protein data, was 21 mm Hg, and that in the interstitium or terminal lymph was 19 mm Hg; thus they were almost identical. This was due to a heavy leakage of protein resulting from the irritation caused by the incision and clamp-fixation and resembled any case of irritation. With a horizontal body posture there is an outwardly directed filtration in all vascular segments. Part of the fluid will form the fluid layer on the tracheal epithelium and the mucus. The rest is drained, together with the proteins, by the richly developed lymphatic system. In an upright body posture, significant resorption will take place via the submucosal venous plexus, with less risk of edema.

Airway Repair with Pedicled Composite Grafts—Clinical Experience

In particular surgical situations, part of the airway wall may have to be excised for different reasons, perhaps because of a large tumor or extensive scar tissue. The repair of large laryngotracheal defects, impossible to reconstruct with segmental resection and end-to-end anastomosis or to repair with existing adjacent tissue, is a challenge. A prerequisite for reconstruction of such defects is a graft composed of well-vascularized mucosal lining and a supportive framework to keep the airway patent. A three-stage procedure, based on the creation of an autogenous mucosal cyst, has been developed and used clinically in a series of patients. The three most recent patients who have undergone reconstruction with pedicled muscle Proplast mucosa grafts are presented. In two of the patients, large unilateral laryngeal tumors were removed and the third had a large patent tracheostoma.

The Autogenous Mucosal Cyst Procedure: Experimental Reconstructive Surgery of the Airway with a New Composite Graft Technique

Autogenous buccal mucosa was transplanted to the pretracheal region in five beagles. Subsequently a cyst developed in which the graft constituted the main part of the cyst wall. After 4 to 13 weeks the cyst was explored and a perforated autogenous cortical bone plate was sutured to its vertex. After a further 5 to 7 weeks the resulting composite graft was sutured to an anterior tracheal window defect. All dogs survived. They did not lose weight. One dog had moderate breathing difficulties during exertion. At bronchoscopy, which was performed in all dogs, no contractions or granulations were seen but the stability of the airway wall in the grafted areas was reduced. These areas were removed after 8 to 15 months and studied by light microscopy, scanning electron microscopy and transmission electron microscopy. The mucosa survived in all cases. Total resorption of the bone graft occurred in all but two cases, in which remnants were found.

Vocal fold lateralization using carbon dioxide laser and fibrin glue

Lateralization of one or both vocal folds is a generally accepted surgical principle for the relief of the airway obstruction caused by bilateral vocal fold paralysis. A modified, entirely endoscopic method of lateralization has been developed, employing a carbon dioxide laser to reduce the bulk of the fold, and fibrin glue to maintain the lateral position. The results of 18 operations on 15 patients, including six who had unsatisfactory results after previous surgery, were analyzed and compared retrospectively with the results from 22 patients operated on before the introduction of the method. The patients ability to perform everyday activities improved in 12 cases, which paralleled the results of the previous, more cumbersome methods. The incidence of re-operation was comparable, given the shorter follow-up after the more recent method.

Reconstruction of the Airway with a Composite Alloplastic and Autogenous Graft An Experimental Study

A method by which an alloplast can be lined with mucosa and thereafter used as a composite pedicled graft is described and discussed. Autogenous buccal mucosa was transplanted to the pretracheal region in five beagles. Subsequently a cyst developed in which the graft constituted the main part of the cyst wall. After 5 to 6 weeks the cyst was explored and a Proplast sheet was sutured to its exterior. After another 3-9 weeks the area was explored again. A composite graft had then formed comprising buccal mucosa on the outside, stabilized by Proplast and supplied by blood vessels arising from the strap muscles and their fascia. After opening of the cyst, the composite graft was used to repair a tracheal defect in the same dog. All of the dogs survived and they did not lose any weight. The graft areas were removed 5 1/2-9 months after the tracheal window repair. Tracheoscopy was performed at least twice on each dog. The grafted areas were also studied by light microscopy, scanning electron microscopy and transmission electron microscopy. The grafts survived in all cases. There was no tendency towards graft extrusion. Connective tissue cells predominated in the pores of the Proplast framework, in which small foci of metaplastic bone formation were also seen.