Obesity, hypertension and atherosclerosis

OBJECTIVE: To determine the effect on oxygen saturation of instilling a saline bolus into artificial airways prior to suctioning, as measured by pulse oximeter. DESIGN: Quasi-experimental, single-case, counterbalanced design. SETTING: The surgical, medical and coronary intensive care units of a federal, teaching medical center. SUBJECTS: Subjects were 40 men, more than 40 years old, in need of intensive care nursing and mechanical ventilation. INTERVENTIONS: Subjects were suctioned as needed for 24 hours. A 5-mL saline bolus was instilled every other time the subject was suctioned. Outcome measurements were done immediately before and after suctioning and at 1-minute intervals for 5 minutes after suctioning. MAIN OUTCOME MEASURES: Noninvasive oxygen saturation values. RESULTS: The instillation of a saline bolus was found to have an adverse effect on oxygen saturation that worsened over time. Significant changes in oxygen saturation as a result of saline bolus instillation were found at 2,3,4 and 5 minutes after instillation. CONCLUSIONS: These results indicate that instilling saline prior to suctioning has an adverse effect on oxygen saturation. These results support the recommendation that the practice of instilling saline prior to suctioning should be abandoned as a routine procedure. More study is needed to investigate whether a specific group of patients may actually benefit from this procedure.     

Instrument development in the measurement of unsupported arm exercise endurance in normal adult subjects

Endotracheal suctioning of intubated infants produces profound changes in cardiovascular and cerebral hemodynamics, but the mechanisms regulating these changes are not fully understood. To determine the role of the autonomic nervous system in regulating these physiologic changes, we investigated the effects of endotracheal suctioning on heart rate (HR), mean arterial blood pressure (MABP), and renal sympathetic nerve activity (RSNA) in nine ventilated newborn lambs. In the first part of the study (n = 6), ventilation was interrupted for suctioning. With suctioning (15 s), HR decreased by 39 +/- 6% (p < 0.05), whereas MABP and RSNA increased significantly (p < 0.05) by 36 +/- 5% and 68 +/- 8%, respectively. These changes were significantly (p < 0.05) larger than changes observed during disconnection from the ventilator (15 s) without suctioning. Administration of atropine (0.02 mg/kg) blocked the HR response to suctioning without altering MABP or RSNA changes. After bilateral vagotomy, suctioning produced no changes in any parameter. When a closed tracheal suction system was used and ventilation was maintained, suctioning again resulted in significant (p < 0.05) increases in MABP (+10 +/- 3%) and RSNA (+34 +/- 5%) and a decrease in HR (-15 +/- 4%). These data suggest that suctioning stimulates sympathoexcitatory receptors localized in large airways whose afferent fibers course within the vagus, resulting in increased sympathetic activity, which induces peripheral vasoconstriction and elevates MABP. In contrast, the HR response appears to be mediated by increased parasympathetic activity as this is abolished by atropine.     

Teaching the teachers

Respiratory distress with episodes of cyanosis, intercostal retraction and sibilant rhonchi occurred in a 2-year-old boy over a 48-hour period following serious smoke inhalation. Worsening of the child's condition accompanied these findings, culminating in sudden loss of air entry, severe respiratory distress and loss of consciousness, which necessitated endotracheal intubation for resuscitation. Pronounced improvement followed removal of two pseudomembranous bronchial casts from the airway by suctioning, and thereafter recovery was uneventful.     

Clearance of mucus from endotracheal tubes during intratracheal pulmonary ventilation

BACKGROUND: Intratracheal pulmonary ventilation (ITPV) is a form of tracheal gas insufflation in which all gas emerges in a cephalad direction from the tip of a reverse-thrust catheter positioned within an endotracheal tube. In vitro experiments have shown that this rapid gas flow, with 5 ml/h of normal saline added to the gas flow, continuously removes tracheal secretions from within the endotracheal tube. The authors evaluated its effectiveness to remove mucus in long-term studies in sheep. METHODS: Fourteen healthy sheep were tracheally intubated and ventilated for 3 days with ITPV or with volume-controlled ventilation. Measurements were made of the total amount of secretions within the endotracheal tubes (weight gain), the protein content within the endotracheal tubes, and the increase in resistance to constant air flow. The structure of the airways was examined grossly and histologically. Three additional sheep were ventilated for 24 h with ITPV, and Evans Blue dye was added to the saline to assess the distribution of the infused saline. RESULTS: There was significantly less mucus in endotracheal tubes of sheep ventilated with ITPV than with conventional ventilation, as shown by minimal weight gain (0.70 +/- 0.14 g vs. 2.44 +/- 0.81 g; P < 0.001), lower protein content (14.09 +/- 10.79 mg vs. 294.99 +/- 153.06 mg; P < 0.001), and lower resistance to constant air flow (6.15 +/- 0.54 cm H2O x 1(-1) x s(-1) vs. 15.34 +/- 5.28 cm H2O x 1(-1) x s(-1); P < 0.001). Results of gross and histological examinations of the tracheas of animals in both groups were similar, and the tracheas were well preserved. More than 95% of the instilled saline was recovered during ITPV. Only traces of Evans Blue dye were found near the tip of the endotracheal tubes. CONCLUSION: Intratracheal pulmonary ventilation makes it possible to keep the endotracheal tubes of sheep ventilated for 3 days free of mucus without suctioning.     

Junctional tachycardia during radiofrequency ablation of the slow pathway in patients with AV nodal reentrant tachycardia: effects of autonomic blockade

BACKGROUND: Exogenous surfactant treatment of hyaline membrane disease is known to modify the pattern of radiological changes on the chest radiograph. OBJECTIVES: To analyse and attempt to explain the radiological changes observed after exogenous surfactant treatment. Materials and methods. Thirty-nine premature infants with typical hyaline membrane disease. RESULTS: Transient asymmetrical clearing with better aeration of the right lung in the absence of malposition of the tip of the endotracheal tube was observed in nine cases (23 %). This asymmetry was patchy in one case. It was due to a complication of mechanical ventilation in three cases [pneumothorax (n = 2) and pneumomediastinum (n = 1)]. In the other six cases, asymmetrical clearing could be related to the anatomical position of the right main bronchus, which facilitates distribution of surfactant to the right lung. However, the course of these premature infants was similar to that of infants with symmetrical chest radiological findings after treatment. CONCLUSIONS: Asymmetrical clearing of chest radiographs, sometimes patchy, after surfactant treatment requires exclusion of pneumothorax or infection but has no influence on clinical outcome.     

Can nurses safely assess the need for endotracheal suction in short-term ventilated patients, instead of using routine techniques?

Most literature describes endotracheal suction as a hazardous procedure associated with numerous complications and proposes that it should only be performed as necessary to minimize these complications. Other authors suggest endotracheal suction only after assessment predisposes patients to a number of different complications. This article describes a controlled study to compare and contrast the differences in endotracheal suction outcomes in patients who received ritualized 2 hourly suctioning and those who received it following assessment. A group of qualified nurses in an Intensive Care Unit were taught auscultation skills to assess a patient's needs for suctioning and all the nurses received educational training regarding endotracheal suctioning. Short-term ventilated patients were allocated to receive endotracheal suctioning either when the need for it was determined by assessment only or routinely, using a standardized suctioning technique. The results demonstrated a clear increase in nurses' knowledge regarding endotracheal suctioning. The assessed group of patients demonstrated significantly better outcomes and less complications than the controlled group in relation to changes in peak airway pressures, heart rate and mean arterial pressure pre- and post-endotracheal suctioning, and the amount of secretions obtained on suctioning. Although only preliminary, these results do provide support for the view that endotracheal suction only in response to assessment is better practice for short-term ventilated patients.     

High-resolution CT of the lung: determination of the usefulness of CT scans obtained with the patient prone based on plain radiographic findings

OBJECTIVE: We assessed the usefulness of chest radiographs for predicting whether high-resolution CT scans obtained with the patient prone would be valuable in assessing suspected diffuse lung disease. MATERIALS AND METHODS: In 100 consecutive patients undergoing high-resolution CT, findings on plain chest radiographs were classified as normal, possibly abnormal, or abnormal. CT scans obtained with the patient supine were assessed for the presence and distribution of lung abnormalities without knowledge of the plain radiographic classification. A second review of the CT scans was done with equal numbers of scans obtained with the patient prone and with the patient supine. The usefulness of the CT scans obtained with the patient prone for detecting lung disease was determined and related to the plain radiographic classifications. RESULTS: High-resolution CT scans obtained with patients prone were helpful in excluding or confirming posterior lung abnormalities in 10 (28%) of 36 patients who had normal findings on chest radiographs, five (28%) of 18 patients who had possibly abnormal findings on chest radiographs, and only two (4%) of 46 patients who had abnormal findings on chest radiographs. The proportion of patients who benefited from high-resolution CT scans obtained with the patient prone was significantly lower among the patients with abnormal findings on chest radiographs than among the patients with normal (p = .008) or possibly abnormal (p = .02) findings on chest radiographs. The two patients with abnormal findings on radiographs in whom CT scans obtained with the patient prone were helpful had minimal radiographic abnormalities. CONCLUSION: In patients with suspected diffuse lung disease, obtaining high-resolution CT scans with the patient prone may be useful when chest radiographs show normal findings, possibly abnormal findings, or minimal abnormalities indicative of diffuse lung disease. However, such scans are of little value in patients whose radiographs show abnormalities indicative of diffuse lung disease.     

Antiandrogen action in the development of androgen insensitivity in S115 mouse mammary tumour cells

In prior studies, we and others have documented a significant reduction by surface chemistry modification in the biological activity of quartz. We further documented that aluminium lactate inhalation one month after quartz exposure significantly suppressed the silica-induced alveolitis, reduced the pathological process and decreased the retention of quartz in the lung tissue. In the present study, we evaluated the efficacy of aluminium inhalation in altering the silicosis process after disease was recognized by standard chest radiography. Twenty-four sheep were enrolled in the study. The 14 silica exposed sheep had an abnormal chest radiograph of the ILO category 1 or above after 3 years of 100 mg Minusil-5 in 100-ml saline intratracheal injections. Ten control sheep were exposed to saline intratracheal injections. All sheep were evaluated at 3-month intervals by chest radiography, lung function and lung lavage. At month 36 of the study, all 14 sheep had an abnormal chest radiograph while the radiographs of controls remained normal. The sheep with silicosis had significantly reduced lung functions and increased cellularity, phospholipids and hyaluronan. These changes persisted during the next 12 months without exposure or treatment. At month 48 and at monthly intervals after, for 12 months, aerosol inhalations were carried out with saline alone for control and seven silicotic sheep and with 100 mg of aluminium lactate in 10 ml saline generated with a Bird Mark 8 pressure ventilator for the other seven silicotic sheep. All sheep were evaluated at 3-month intervals by chest radiography, lung function and lung lavage.(ABSTRACT TRUNCATED AT 250 WORDS)     

Techniques and results of direct-access minimally invasive mitral valve surgery: a paradigm for the future

As a model of the meconium aspiration syndrome (MAS) of human infants, adult rabbits and newborn rhesus monkeys received intratracheal instillation of human meconium to induce pulmonary injury. Injured rabbits were ventilated with 100% O2 and divided into four treatment groups, receiving: 1) bronchoalveolar lavages (BAL) with dilute KL4-Surfactant; 2) lavages with equal volumes of sterile saline; 3) a single intratracheal bolus of KL4-Surfactant, 100 mg/kg; and 4) no treatment. The untreated rabbits developed atelectasis, a fall in pressure-volume levels and in partial pressure of O2 in arterial blood (PaO2) from approximately 500 to < 100 mm Hg, and severe pulmonary inflammation between 3 and 5 h after instillation of meconium. Rabbits treated by BAL with dilute KL4-Surfactant showed rapid and sustained recovery of PaO2 to approximately 300 mm Hg within minutes, a return toward normal pressure-volume levels, and diminished inflammation. Rabbits receiving BAL with saline failed to show recovery, and rabbits treated with a bolus of surfactant intratracheally exhibited a transient response by 1-2 h after treatment, but then returned to the initial atelectatic state. Newborn rhesus monkeys, after receiving human meconium intratracheally before the first breath, developed severe loss of pulmonary function. Treatment of these monkeys 1-5 h after birth with BAL with dilute KL4-Surfactant produced clearing of chest radiographs and a rapid improvement in pulmonary function with ratios of partial pressure of O2 in arterial blood to the fraction of O2 in the inspired air rising into the normal range where they remained through the 20-h period of study. The studies indicate that pulmonary function in two models of severe meconium injury respond rapidly to BAL with dilute KL4-Surfactant.     

Measurement of absolute lung volumes by imaging techniques

In this paper, the techniques available for estimating total lung capacities from standard chest radiographs in children and infants as well as adults are reviewed. These techniques include manual measurements using ellipsoid and planimetry techniques as well as computerized systems. Techniques are also available for making radiographic lung volume measurements from portable chest radiographs. There are inadequate data in the literature to support recommending one specific technique over another. Though measurements of lung volumes by radiographic, plethysmographic, gas dilution or washout techniques result in remarkably similar mean results when groups of normal subjects are tested, in patients with disease, the results of these different basic measurement techniques can differ significantly. Computed tomographic and magnetic resonance techniques can also be used to measure absolute lung volumes and offer the theoretical advantages that the results in individual subjects are less affected by variances of thoracic shape than are measurements made using conventional chest radiographs.     

Neonatal pneumopericardium

The clinical data and radiographs of 50 neonates with pneumopericardium (PPC) were reviewed. Most of these neonates were premature, low-birth-weight infants with hyaline membrane disease who required ventilatory assistance. The presence of other extraventilatory air prior to (or concurrent with) PPC, the use of cardiopulmonary resuscitation with intracardiac drug administration, and improper endotracheal tube placement were contributory factors. However, it was not possible to determine why some infants progressed to PPC and others, with similar disease and predisposing conditions, did not. The primary radiographic sign of PPC is the "halo" sign, which was apparent in 96% of these cases. When this sign was not present, other signs, such as the "pericardial line" sign, were helpful. The overall mortality was 72%. Thirty-three per cent of the fatalities were related to PPC; however, the long-term prognosis is probably more closely related to the severity of underlying lung disease or other complications than to PPC.     

Bibliographic errors in Revista Espa?ola de Enfermedades Digestivas. A retrospective study of the year 1995

To determine whether total lung capacity (TLC) can be measured from plain chest radiographs in patients with pneumonectomy, we examined 20 such patients (17 male, 3 female) who had pneumonectomy for lung carcinoma. In 16 patients the right lung was preserved, and in 4 the left. The TLC was measured with the helium dilution method and by planimetry of the anterior and lateral projections of the lung on chest radiographs, summing the anterior and lateral projected areas of the lung to a single value, S. The correlation between S and TLC by helium gas dilution was r = 0.95. Linear fit of TLC to S explained 99.5% of the variance in TLC, with the equation. The side resected did not influence the predictive value (p < 0.001). The interquartile range of the residual error was +/-130 ml, and standard error was 64 ml. Therefore in patients with pneumonectomy, TLC of the preserved lung may be estimated within +/-130 ml by planimetry of the anterior and lateral chest radiographs.     

Morphologic features and function of the airways in early asbestosis in the sheep model

Previous studies of asbestos exposure in humans and small animals have suggested that air flow limitation associated with small airway disease may be an early manifestation of asbestosis, but the subject is still controversial. In this report, we present the airway morphologic aspects and function of our sheep model of the disease. Three groups of 6 sheep were exposed to repeated intratracheal injections of either saline (control group), 2 mg of UICC Canadian chrysotile asbestos in saline (low exposure group), or 128 mg of the same fibers (high exposure group). At the end of the twelfth month of exposure, an alveolitis had developed in the high exposure group only. Detailed pulmonary function tests were followed within 48 by lung biopsies according to methods described, to which were added air-helium flow-volume curves. Lung biopsies in control and low exposure groups did not demonstrate significant morphologic changes, whereas all biopsies in the high exposure group showed alveolitis characterized by an alveolar and interstitial accumulation of macrophages and mononuclear cells without interstitial fibrosis. On all biopsies, over half of the airways were altered by a similar peribronchiolar process, which at times compressed the peripheral airways. Functionally there was no significant difference between low exposure and control groups. However, compared with the control group, the high exposure group had significantly lower vital capacity (2.0 +/- 0.1 versus 2.9 + 0.1 L, p less than 0.01), lower static lung compliance (91 + 13 versus 132 + 9 ml/cmH2O, p less than 0.05), higher isoflow volume (2.15 + 0.08 versus 1.4 + 0.1 L, p less than 0.01), and higher upstream resistance below the isoflow volume (3.3 + 0.2 versus 1.3 + 0.3 cmH2O L/s, p less than 0.02). These data demonstrate that in the early asbestos-induced peribronchiolar alveolitis of the sheep, which restricts lung volumes, there is a concomitant small airway disease that significantly limits air flow.     

Palisaded encapsulated neuroma of the nasal fossa

The aim of the study was to assess the potential application of teleradiology in the neonatal intensive care unit (NICU) by ascertaining whether any decrease in conspicuity of anatomic detail or interventional devices in the chest radiographs of premature infants is caused by picture archiving and communication system (PACS)-based soft copy interpretation of 10 : 1 compressed images. One hundred digital chest radiographs of low-birthweight infants were obtained in the NICU using a storage phosphor system. Laser-printed images were interpreted and the data set for each radiograph was then irreversibly compressed by a 10 : 1 ratio. Four radiologists with extensive PACS experience used a five-point grading system to score laser-printed hard copy images for the visibility of six parameters of anatomic landmarks and interventional devices in the chest. Compressed soft copy images displayed on 2K PACS workstation were subsequently scored using the same approach. Statistical manipulation demonstrated no loss of anatomic detail in five of the six parameters scored, with minimal difference in one landmark, the retrocardiac lung assessment. While further study is required to assess the clinical impact of the variance noted when evaluating lung parameters, the preservation or improvement of information in the remaining parameters following irreversible compression and soft copy interpretation is promising for the potential use of teleradiology in this population.     

Tracheoplasty with an intercostal pedicle flap for tracheal neurilemmoma--a case report

PURPOSE: Negative pressure pulmonary oedema (NPPE) is a well-recognized but rare complication secondary to upper airway obstruction such as laryngeal spasm during emergence from general anaesthesia. Cauterization of the second and third thoracic sympathetic ganglia is a treatment for hyperhidrosis of the hands. We report a case of NPPE induced by direct suctioning of the endotracheal tube adapter during thoracic sympathetic ganglionectomy without recognized upper airway obstruction. CLINICAL FEATURES: A 19-yr-old otherwise healthy, non-smoking man was scheduled for elective bilateral chest endoscopic ablation of the second and third thoracic sympathetic ganglion for hyperhidrosis of the hands under general anaesthesia. To view and cauterize the ganglion with the endoscope, the surgeon requested cessation of positive pressure ventilation. As the surgeon could not satisfactorily visualize the target ganglia, he requested brief application of wall suction via the ETT tube adapter. A pressure of -100 mmHg was generated which lasted for three to four seconds. The goal was to reduce further the lung volume by increasing the pneumothorax produced by the endoscope. The patient developed negative pressure pulmonary oedema without upper airway obstruction. CONCLUSION: This case demonstrated that intrathoracic negative pressure generated by direct ETT adapter suctioning may produce pulmonary oedema similar to that induced by laryngeal spasm during the emergence of general anaesthesia.     

Regarding Kumar et al. IJROBP 31(3):477-483; 1995

OBJECTIVE: We present a computer-aided diagnostic technique for identifying nodular interstitial lung disease on chest radiographs. The fractal dimension was used as a numerical measure of image texture on digital chest radiographs to distinguish patients with normal lung from those with a diffuse nodular interstitial abnormality. MATERIALS AND METHODS: Twenty digitized chest radiographs were classified as normal (n = 10) or as containing diffuse nodular abnormality (n = 10) on the basis of readings assigned according to the classification of the International Labour Organization. Regions of interest (ROIs) measuring 1.28 cm2 were selected from the intercostal spaces of these radiographs. The fractal dimension of these ROIs was estimated by power spectrum analysis. The cases were not subtle. RESULTS: The fractal dimension provided statistically significant discrimination between normal parenchyma and nodular interstitial lung disease. The area under the receiver operating characteristic curve was 0.90 (+/- 0.02). One operating point provides sensitivity of 88% with a specificity of 80%. CONCLUSION: The fractal dimension can provide a measure of lung parenchymal texture and shows promise as an element of computer-aided diagnosis, characterization, and follow-up of interstitial lung disease.     

Effect of ventilation on movement of surfactant in airways

The effect of ventilation on movement of surfactant in airways was studied in rat lungs. Male albino rats were anesthetized and sacrificed by exsanguination. The trachea was cannulated and the diaphragm opened to allow the lungs to collapse. The lungs were left in chest and kept at minimal volume, or at constant inflation with air, or were ventilated with air, nitrogen or oxygen. At the end of 3 hr the extrapulmonary airways (EPA), i.e. trachea and bronchi, were separated from the lungs and flushed with 40 ml isotonic saline. The surface tension and lecithin content of the saline wash was then measured. The surface activity and lecithin content of the EPA wash did not change if the lungs were kept at minimal volume or at constant inflation, but increased following ventilation. This increase was directly related to the duration of ventilation and to the tidal volume and inversely related to the end-expiratory pressure. It was independent of O2 concentration of the gas used for ventilation. The results suggest that ventilation enhances the movement of surfactant in airways and that positive end-expiratory pressure prevents this effect of ventilation.     

Flap of the musculus latissimus dorsi to prevent alveolar air leakage from sectional plane of the lung after resection of metastatic pulmonary and chest wall tumor

Alveolar air leakage after pulmonary resection usually heals with adequate pleural drainage, but must be more actively treated if leakage may be severe. If left untreated, the postresection space can lead to empyema. We used a muscle flap to prevent alveolar air leakage from a large sectional plane of the lung resected because of metastases in the lung and chest wall. A 48-year-old man complained of pain and a mass on the right side of his back. He had undergone resection and chemotherapy for clear cell sarcoma that originated on the back of the left hand when 43 years of age, wedge resection of the right lower lobe of the lung for a metastatic pulmonary tumor at 46 years, and lobectomy of the same lobe for a recurrence of the metastatic pulmonary tumor at 47 years. The diagnosis was of a metastatic tumor to the right chest wall with peripheral pulmonary tumors of the right upper and middle lobes. Resection of the chest wall and the lung including the tumors was done. Much air leakage from the extensive sectional plane of the right upper and middle lobes was seen intraoperatively, and this plane was therefore covered with a flap of the musculus latissimus dorsi. Chest tubes were removed on day 7 postoperatively when air leakage was no longer seen. Subcutaneous emphysema, which appeared on day 14 postoperatively, required redrainage of the pleural air space, but pleurodesis was effective. Use of a muscle flap was simple and effective for covering of a sectional plane of the lung, and should be considered when alveolar air leakage may be extensive.     

Magnetic resonance imaging of a mediastinal ependymoma

Ependymomas typically occur in the brain and spinal cord, and represent 5% and 16% of primary intracranial and spinal cord tumors respectively. Ependymomas arising outside the central nervous systems are uncommon and when they do occur are usually seen in the sacrococcygeal region. Other reported sites include the pelvis, spinal nerve roots, and lung. An extraspinal mediastinal ependymoma is a rare occurrence, with only two previously reported cases to our knowledge. In both instances, the lesion arose in the posterior mediastinum, and were imaged with either chest radiographs alone or chest radiographs and computed tomography. In our case, plain radiography was followed by magnetic resonance imaging. This report documents the clinical, pathological, and magnetic resonance imaging findings in a case of a posterior mediastinal ependymoma. Primary mediastinal ependymomas are rare lesions that may be considered in the differential diagnosis of a posterior mediastinal mass.     

Diffuse airway narrowing from carcinoma metastatic to the bronchial submucosa: identification by chest CT

The differential diagnosis of dyspnea in patients with prior malignancy and nondiagnostic chest radiographs is broad. We report a case of breast carcinoma diffusely metastatic to the bronchial submucosa presenting as obstructive airway disease. Chest radiographs failed to suggest metastatic disease as the cause of dyspnea. CT, however, revealed the unusual finding of diffusely thickened and narrowed airways. Carcinoma confined to airway submucosa was identified using bronchial biopsy. We suggest that diffuse airway narrowing from submucosal metastasis can be demonstrated by CT and should be added to the differential diagnosis of dyspnea in cancer patients with nondiagnostic chest radiographs and evidence of airflow obstruction.