Injury and repair of tracheobronchial cartilage following accidental exposure to ehtyleneimine. (9/158)

A fatal case following ehtyleneimine inhalation is described. Profound destructive effects on tracheobronchial cartilage were found at necropsy after an interval of apparent recovery from early phases of poisoning. The pathogenesis of these cartilaginous changes is discussed. It is proposed that they may have been due to proteases liberated from liberated from mucosal granulation tissue.  (+info)

Nasal and oral contribution to inhaled and exhaled nitric oxide: a study in tracheotomized patients. (10/158)

Nitric oxide (NO) is produced at different sites in the human airways and may have several physiological effects. Orally-produced NO seems to contribute to the levels found in exhaled air. Autoinhalation of nasal NO increases oxygenation and reduces pulmonary artery pressure in humans. The aim of this study was to measure the concentration and output of NO during nasal, oral and tracheal controlled exhalation and inhalation. Ten tracheotomized patients and seven healthy subjects were studied. The mean+/-SEM fraction of exhaled NO from the nose, mouth and trachea was 56+/-8, 14+/-4 and 6+/-1 parts per billion (ppb), respectively. During single-breath nasal, oral and tracheal inhalation the fraction of inhaled NO was 64+/-14, 11+/-3 and 4+/-1, respectively. There was a marked flow dependency on nasal NO output in the healthy subjects, which was four-fold greater at the higher flow rates, during inhalation when compared to exhalation. There is a substantial contribution of nasal and oral nitric oxide during both inhalation and exhalation. Nasal nitric oxide output is markedly higher during inhalation, reaching levels similar to those that are found to have clinical effects in the trachea. These findings have implications for the measurement of nitric oxide in exhaled air and the physiological effects of autoinhaled endogenous nitric oxide.  (+info)

Effects of tracheotomy on respiratory mechanics in spontaneously breathing patients. (11/158)

Tracheotomy is a method of intubating the trachea, which is employed in several clinical settings, including the treatment of head and neck neoplasms. Tracheotomy is believed to facilitate weaning through changes in respiratory mechanics. Existing information concerning functional changes associated with tracheotomy are limited to comparisons with orotracheal intubation. In this study, respiratory mechanics were monitored in seven spontaneously breathing patients, before and after an elective tracheotomy was performed for surgical treatment of cancer. Campbell diagrams were constructed by plotting pressure, obtained with an oesophageal balloon catheter, against volume, obtained from a pneumotachograph placed at the airway opening. Work of breathing was calculated as the internal area of the Campbell diagram and was partitioned into its elastic and inspiratory and expiratory resistive components. Oesophageal pressure was also used to quantify intrinsic positive end-expiratory pressure (PEEPi) and the pressure-time product (PTP), which is considered to be proportional to the oxygen cost of breathing. PTP was divided into its resistive and elastic components. Inspiratory resistive work, PEEPi, inspiratory PTP, as well as its resistive and elastic components were significantly reduced by tracheotomy. Tracheotomy significantly reduces work of breathing and pressure-time product in spontaneously breathing patients.  (+info)

Subcutaneous emphysema and pneumomediastinum as presenting manifestations of neonatal tracheal injury. (12/158)

Neonatal tracheal injury/perforation is an uncommon complication of traumatic deliveries or endotracheal intubation. We present a case of neonatal tracheal injury following delivery at term that presented with subcutaneous emphysema and pneumomediastinum before any attempt at intubation. The clinical course, treatment, and outcome are described.  (+info)

Instillation of normal saline before suctioning in patients with pneumonia. (13/158)

This study was conducted to investigate the effects of a no saline, a 2 ml and a 5 ml saline instillation prior to endotracheal suctioning on oxygen saturation in patients with pneumonia. The subjects in this study were 16 pneumonic patients with a tracheotomy tube, who had been admitted to the neuro-surgical intensive care unit at a university hospital in Seoul Korea. All three (0, 2 and 5 ml) saline instillation methods were applied to the 16 patients. The methods were randomly assigned to each patient. Each of the instillation methods was applied in a four-step sequence: 1) recording the level of oxygen saturation (baseline levels), 2) instilling normal saline, 3) supplying oxygen and suctioning, and 4) recording the level of oxygen saturation. The oxygen saturation was evaluated using pulse oximetry. The recovery times for oxygen saturation to return to baseline levels following suctioning were, just after suctioning, 45 seconds after suctioning and in excess of 5 minutes with 0, 2 and 5 ml saline instillations, respectively. Instillation of normal saline before suctioning could have an adverse effect on oxygen saturation, and should be used carefully as a routine intervention in patients who have pneumonia.  (+info)

Decreased surface tension of upper airway mucosal lining liquid increases upper airway patency in anaesthetised rabbits. (14/158)

The obstructive sleep apnoea syndrome (OSA) is a disorder characterised by repetitive closure and re-opening of the upper airway during sleep. Upper airway luminal patency is influenced by a number of factors including: intraluminal air pressure, upper airway dilator muscle activity, surrounding extraluminal tissue pressure, and also surface forces which can potentially act within the liquid layer lining the upper airway. The aim of the present study was to examine the role of upper airway mucosal lining liquid (UAL) surface tension (gamma) in the control of upper airway patency. Upper airway opening (PO) and closing pressures (PC) were measured in 25 adult male, supine, tracheostomised, mechanically ventilated, anaesthetised (sodium pentabarbitone), New Zealand White rabbits before (control) and after instillation of 0.5 ml of either 0.9 % saline (n = 9) or an exogenous surfactant (n = 16; Exosurf Neonatal) into the pharyngeal airway. The gamma of UAL (0.2 microl) was quantified using the 'pull-off' force technique in which gamma is measured as the force required to separate two curved silica discs bridged by the liquid sample. The gamma of UAL decreased after instillation of surfactant from 54.1 +/- 1.7 mN m-1 (control; mean +/- S.E.M.) to 49.2 +/- 2.1 mN m-1 (surfactant; P < 0.04). Compared with control, PO increased significantly (P < 0.04; paired t test, n = 9) from 6.2 +/- 0.9 to 9.6 +/- 1.2 cmH2O with saline, and decreased significantly (P < 0.05, n = 16) from 6.6 +/- 0.4 to 5.5 +/- 0.6 cmH2O with surfactant instillation. Findings tended to be similar for PC. Change in both PO and PC showed a strong positive correlation with the change in gamma of UAL (both r > 0.70, P < 0.001). In conclusion, the patency of the upper airway in rabbits is partially influenced by the gamma of UAL. These findings suggest a role for UAL surface properties in the pathophysiology of OSA.  (+info)

Ketamine-xylazine-induced slow (< 1.5 Hz) oscillations in the rat piriform (olfactory) cortex are functionally correlated with respiration. (15/158)

The occurrence of low frequency (<1.5 Hz) cerebral cortical oscillations during slow-wave sleep has recently lead to the suggestion that this pattern of activity is specifically associated with conditions in which the brain is mostly closed to external inputs and running on its own. In the current experiments, we used a combination of in vivo intracellular and extracellular field potential recordings obtained under conditions of ketamine-xylazine anesthesia to examine slow-wave behavior in the olfactory system. We demonstrate the occurrence of low-frequency oscillations in field potentials of both the olfactory bulb and cortex and in the membrane potentials of cortical pyramidal cells. By monitoring ongoing breathing, we also show that these oscillations are all correlated with the natural breathing cycle. Using a tracheotomized preparation, we demonstrate that slow oscillatory patterns could occasionally be produced even when air is no longer entering the nose, supporting the view that the olfactory system has an intrinsic propensity to oscillate. However, in the case of tracheotomized rats, the amplitude and regularity of the oscillations as well as their patterns of correlation are disrupted. All temporal relationships were restored when air was pulsed into the nostrils. We conclude that, in the olfactory system of freely breathing rats, there is a strong relationship between the occurrence and timing of slow oscillations and the ongoing periodic sensory input resulting from respiration. This coupling between olfactory cortex slow oscillations and respiration may result from the interaction between respiratory-related rhythmic input and the tendency for olfactory structures to oscillate intrinsically. We believe this finding has important functional as well as evolutionary implications.  (+info)

A TECHNIQUE OF TRACHEOSTOMY. (16/158)

The Bjork technique of performing tracheostomy is outlined. This consists of suturing an inverted U-shaped flap of trachea to the skin edge. Some of its advantages, particularly in infants, are outlined.  (+info)