Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ATELECTASIS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,567 records · Page 87Linked to original sources
PubMed1987

Unusual case of enlarging pulmonary mass.

Rounded atelectasis is an uncommon form of pulmonary collapse that presents as an asymptomatic lung mass, and thus, can appear very similar to a pulmonary neoplasm. One feature that has been used to differentiate rounded atelectasis from a pulmonary malignancy is the lack of growth observed in cases of rounded atelectasis. The case presented here demonstrates that it is possible for rounded atelectasis to increase in size. This is the first documented case of enlargement of rounded atelectasis and shows that this disorder should be added to the list of benign causes of an enlarging pulmonary mass.

Aged↗
PubMed1983

[Continuous positive pressure respiration by nasal route (n-CPAP) as a preferred treatment method in various types of acute respiratory insufficiency in newborn infants].

The process of adaptation for extrauterine life can be easily disturbed by respiratory insufficiency. The surfactant deficiency as well as anatomical and physiological immaturity of a newborn can be considered as etiological factors in some diseases, such as respiratory distress syndrome (RDS), transient tachypnoea (TT) syndrome, segmental atelectasis or pneumonia complicated by atelectasis. The widespread used method of treatment is based on mechanical increase of difference between alveolar and atmospheric pressure. So-called constant distending pressure (CDP) increases functional residual capacity (FRC), keeps alveoli open and finally increases oxygenation of arterial blood. During 3 years period continuous positive airway pressure by nasal route (n-CPAP) was used as only one method in 26 newborns. The newborns were treated because of RDS (15 cases) and pneumonia with atelectasis (11 cases). n-CPAP was starting with pressure 8 cm H2O (0.8 kPa) and FIO2 0.5, if atelectasis with severe dyspnea, hypoxia and forced hyperventilation were found. This method was very well tolerated. 22 newborns treated for 2-7 days--survived, 4 small-for-date babies--died. The most common cause of death was septicaemia complicated by disseminated intravascular coagulation. The moderate hyperbilirubinemia, oliguria with tissue oedema was observed in many cases. The light nostril decubitus were only complications. No pneumothorax was detected. We found n-CPAP as a simple, safe method in treatment of atelectasis in newborns.

Acute Disease↗
PubMed2005

Impact of computed tomography and 18F-deoxyglucose coincidence detection emission tomography image fusion for optimization of conformal radiotherapy in non-small-cell lung cancer.

PURPOSE: To report a retrospective study concerning the impact of fused 18F-fluoro-deoxy-D-glucose (FDG)-hybrid positron emission tomography (PET) and CT images on three-dimensional conformal radiotherapy planning for patients with non-small-cell lung cancer. METHODS AND MATERIALS: A total of 101 patients consecutively treated for Stage I-III non-small-cell lung cancer were studied. Each patient underwent CT and FDG-hybrid PET for simulation treatment in the same treatment position. Images were coregistered using five fiducial markers. Target volume delineation was initially performed on the CT images, and the corresponding FDG-PET data were subsequently used as an overlay to the CT data to define the target volume. RESULTS: 18F-fluoro-deoxy-D-glucose-PET identified previously undetected distant metastatic disease in 8 patients, making them ineligible for curative conformal radiotherapy (1 patient presented with some positive uptake corresponding to concomitant pulmonary tuberculosis). Another patient was ineligible for curative treatment because the fused PET-CT images demonstrated excessively extensive intrathoracic disease. The gross tumor volume (GTV) was decreased by CT-PET image fusion in 21 patients (23%) and was increased in 24 patients (26%). The GTV reduction was > or = 25% in 7 patients because CT-PET image fusion reduced the pulmonary GTV in 6 patients (3 patients with atelectasis) and the mediastinal nodal GTV in 1 patient. The GTV increase was > or = 25% in 14 patients owing to an increase in the pulmonary GTV in 11 patients (4 patients with atelectasis) and detection of occult mediastinal lymph node involvement in 3 patients. Of 81 patients receiving a total dose of > or = 60 Gy at the International Commission on Radiation Units and Measurements point, after CT-PET image fusion, the percentage of total lung volume receiving >20 Gy increased in 15 cases and decreased in 22. The percentage of total heart volume receiving >36 Gy increased in 8 patients and decreased in 14. The spinal cord volume receiving at least 45 Gy (2 patients) decreased. Multivariate analysis showed that tumor with atelectasis was the single independent factor that resulted in a significant effect on the modification of the size of the GTV by FDG-PET: tumor with atelectasis (with vs. without atelectasis, p = 0.0001). CONCLUSION: The results of our study have confirmed that integrated hybrid PET/CT in the treatment position and coregistered images have an impact on treatment planning and management of non-small-cell lung cancer. However, FDG images using dedicated PET scanners and respiration-gated acquisition protocols could improve the PET-CT image coregistration. Furthermore, the impact on treatment outcome remains to be demonstrated.

Adult↗
PubMed1996

Respiratory function after cardiac surgery.

STUDY OBJECTIVE: Cardiac surgery is complicated by decreased postoperative respiratory muscle strength and spirometry with accompanying increased atelectasis. The specific respiratory symptoms attributable to these physiologic changes are unknown, and this study looked at the symptoms and underlying physiology. DESIGN: Convenience sampling of observational cohort. SETTING: Tertiary care university hospital. PATIENTS: One hundred thirty-eight patients undergoing elective surgery were enrolled. INTERVENTIONS: Changes from admission to 8-week postoperative values in atelectasis, pleural effusions, spirometry (forced vital capacity and forced expiratory volume in one second), and respiratory muscle strength (negative inspiratory pressure) were measured. These physiologic changes were compared with changes in respiratory symptoms of cough, wheeze, phlegm, and dyspnea on walking up a slight hill noted from admission to 8-week follow-up by stepward logistic regression. MEASUREMENTS AND RESULTS: Spirometry and negative inspiratory pressure decreased and atelectasis increased from admission to discharge. These disturbances had only incompletely resolved at 8-week follow-up. Some patients reported fewer symptoms of cough (11%), phlegm (9%), wheeze (35%), and dyspnea (46%) at 8 weeks follow-up. Other patients reported increased symptoms of cough (15%), phlegm (10%), wheeze (6%), and dyspnea (4%) at 8 weeks follow-up. Residual atelectasis at 8 weeks was predictive of fewer symptoms of dyspnea (odds ratio [OR] 0.335, p = 0.199; 95% confidence interval [CI] 0.188, 0.597), increased symptoms of dyspnea (OR 855, p = 0.006; 95% CI 6.6, 11052), and increased symptoms of cough (OR 260, p = 0.023; 95% CI 2.13, 31829). Negative inspiratory pressure at 8 weeks was predictive of fewer symptoms of dyspnea (OR 1.05, p = 0.032; 95% CI 1.02, 1.09) and increased symptoms of wheeze (OR 0.7, p = 0.45; 95% CI 0.533, 0999). Forced vital capacity at 8 weeks was predictive of increased symptoms of wheeze (OR 0.005; p = 0.015; 95% CI 0.0060, 0.775). CONCLUSIONS: Postoperative changes in respiratory muscle strength and spirometry can persist up to at least 8 weeks postoperatively. Many patients report a change in respiratory symptoms of cough, phlegm, dyspnea, or wheeze. The change in respiratory symptoms at 8 weeks is correlated with residual respiratory muscle weakness, decrease in spirometry, and residual atelectasis.

Adult↗
PubMed2006

The effect of open lung ventilation on right ventricular and left ventricular function in lung-lavaged pigs.

INTRODUCTION: Ventilation according to the open lung concept (OLC) consists of recruitment maneuvers, followed by low tidal volume and high positive end-expiratory pressure, aiming at minimizing atelectasis. The minimization of atelectasis reduces the right ventricular (RV) afterload, but the increased intrathoracic pressures used by OLC ventilation could increase the RV afterload. We hypothesize that when atelectasis is minimized by OLC ventilation, cardiac function is not affected despite the higher mean airway pressure. METHODS: After repeated lung lavage, each pig (n = 10) was conventionally ventilated and was ventilated according to OLC in a randomized cross-over setting. Conventional mechanical ventilation (CMV) consisted of volume-controlled ventilation with 5 cmH2O positive end-expiratory pressure and a tidal volume of 8-10 ml/kg. No recruitment maneuvers were performed. During OLC ventilation, recruitment maneuvers were applied until PaO2/FiO2 > 60 kPa. The peak inspiratory pressure was set to obtain a tidal volume of 6-8 ml/kg. The cardiac output (CO), the RV preload, the contractility and the afterload were measured with a volumetric pulmonary artery catheter. A high-resolution computed tomography scan measured the whole lung density and left ventricular (LV) volumes. RESULTS: The RV end-systolic pressure-volume relationship, representing RV afterload, during steady-state OLC ventilation (2.7 +/- 1.2 mmHg/ml) was not significantly different compared with CMV (3.6 +/- 2.5 mmHg/ml). Pulmonary vascular resistance (OLC, 137 +/- 49 dynes/s/cm5 versus CMV, 130 +/- 34 dynes/s/cm5) was comparable between groups. OLC led to a significantly lower amount of atelectasis (13 +/- 2% of the lung area) compared with CMV (52 +/- 3% of the lung area). Atelectasis was not correlated with pulmonary vascular resistance or end-systolic pressure-volume relationship. The LV contractility and afterload during OLC was not significantly different compared with CMV. Compared with baseline, the LV end-diastolic volume (66 +/- 4 ml) decreased significantly during OLC (56 +/- 5 ml) ventilation and not during CMV (61 +/- 3 ml). Also, CO was significantly lower during OLC ventilation (OLC, 4.1 +/- 0.3 l/minute versus CMV, 4.9 +/- 0.3 l/minute). CONCLUSION: In this experimental study, OLC resulted in significantly improved lung aeration. Despite the use of elevated airway pressures, no evidence was found for a negative effect of OLC on RV afterload or LV afterload, which might be associated with a loss of hypoxic pulmonary vasoconstriction due to alveolar recruitment. The reductions in the CO and in the mean pulmonary artery pressure were consequences of a reduced preload.

Animals↗
PubMed1992

Ultrasonography of chest diseases: analysis of 154 cases.

Sonographic characteristics of various chest diseases in 154 cases were analysed according to margin of the lesion, internal echogenecity, posterior echo enhancement, air bronchogram etc. We intended to present the basic sonographic patterns of common chest diseases. The study included 10 normal cases, 10 cases with lung abscesses, 31 cases of pneumonia, 24 cases of tumors, 11 cases of obstructive atelectasis, 8 cases of pleuropericarcadial effusions, 10 cases of minimal effusions, 6 cases with pleural thickening, 32 cases of massive pleural effusion with simple compression atelectasis and 12 cases of pneumonia with parapneumonic effusion. Sonographically, normal lung showed hyperechoic zone beneath the chest wall. Identification of arc or ring-shaped wall favored lung abscess. Air bronchogram could only be found in pneumonia. Mass showed various internal echogenecity. The internal echogenecity in obstructive atelectasis was very homogeneous which could not be found in tumor. Pleural thickening showed linear hyperechogenecity beneath the chest wall. In minimal effusion, the line of the diaphragm could be easily identified. Pleuropericardial effusion could be easily diagnosed by chest sonography. The line of the pericarcadium could be clearly identified. The internal echogenecity of massive effusion were various. The internal echogenecity of simple compression atelectasis showed very homogeneous hyperdense internal echogenecity. The internal echogenecity of lung parenchyma in pneumonia with parapneumonic effusion was similar to that of pneumonia. Obstructive atelectasis, mass, consolidation and encapsulated effusion could be differentiated by chest sonography without much difficulty. Sonography could aid chest radiography by giving more morphologic information and was cheaper than computed tomography.

Adult↗
PubMedDate not supplied

Chest radiograph changes after cardiopulmonary bypass in children.

To determine the spectrum of pediatric chest radiograph changes after cardiopulmonary bypass, 98 children (mean age = 5.9 yr, range 4 wk-16 yr) were studied for 3 days postoperatively. Daily A-P radiographs were evaluated for atelectasis, cardiomegaly, pleural effusions, diaphragmatic elevation, mediastinal widening, and pulmonary infiltrates. The overall incidence of atelectasis was 82%, with left lower lobe atelectasis the most common (64%). Right upper lobe atelectasis occurred in 35% of patients, far more common than in the adult. Radiographic changes were then compared with independent variables including patient weight, age, duration of bypass, and fluid balance by multiple linear regression. Pleural effusion correlated with patient weight and duration of bypass. Diaphragmatic elevation correlated with patient weight. Cardiomegaly correlated with patient age. Net fluid balance was a poor predictor of postoperative chest radiograph changes. We conclude that radiographic changes are common after cardiopulmonary bypass in children, that the overall incidence is not markedly different from adults, and that right upper lobe atelectasis occurs more frequently in children.

Adolescent↗
PubMed2004

Pulmonary complications following major head and neck surgery with tracheostomy: a prospective, randomized, controlled trial of prophylactic antibiotics.

OBJECTIVE: To test the hypothesis that extended postoperative antibiotic cover would reduce the incidence of pulmonary complications in patients undergoing major head and neck surgery with tracheostomy. DESIGN: A prospective, randomized, controlled trial was carried out to determine the efficacy of an extended course (5 days) of intravenous amoxicillin-clavulanic acid in reducing the rate of atelectasis and pulmonary infections postoperatively. Other possible risk factors that might predispose to pulmonary complications were also evaluated. SETTING: Tertiary referral center for head and neck surgery. PATIENTS: Consecutive patients younger than 80 years with planned surgery for carcinoma of the oral cavity, pharynx, or larynx were enrolled. Patients with diabetes, those who had received antibiotics within 1 week before surgery, and those with preexisting pulmonary disease were excluded. INTERVENTION: Patients were randomly assigned no antibiotics or a 5-day course of intravenous amoxicillin-clavulanic acid postoperatively. MAIN OUTCOME MEASURES: The development of pulmonary complications (pulmonary infection or atelectasis). RESULTS: Eighty-six patients were enrolled; 73 patients met the criteria for analysis. Thirty-four (47%) developed pulmonary complications; 29 (40%) had a pulmonary infection. An extended course of antibiotics did not reduce the rate of pulmonary infections (P =.57). Positive risk factors for a pulmonary infection were presence of preoperative obstructive lung function and postoperative atelectasis. CONCLUSIONS: An extended course of antibiotics did not prevent the development of postoperative pulmonary infections in patients undergoing major head and neck surgery with tracheostomy. Poor pulmonary function and postoperative atelectasis emerged as significant risk factors for pulmonary infection.

Amoxicillin↗
PubMed1978

Intermittent mandatory ventilation and controlled mechanical ventrilation without positive end-expiratory pressure following cardio-pulmonary bypass.

In a group of 18 male patients undergoing coronary artery bypass grafting with cardiopulmonary bypass, the overall incidence of post-operative atelectasis was 60%. Nearly three-quarters occurred during anaesthesia. After operation there was no difference whether CMV or IMV without PEEP was provided overnight. Atelectasis already present did not improve and further atelectasis occurred. A role for IMV is not excluded, since it facilitates the use of PEEP. Many factors operate and interact to provoke atelectasis during anaesthesia, which increases post-operative morbidity. Many of these factors are prevertible or reversible if their physiological basis is understood. Optimal post-operative ventilation should be tailored to the needs of the individual patient and demands close co-operation between anaesthetist and surgeon.

Anesthesia↗
PubMed1996

Airway closure and intraoperative hypoxaemia: twenty-five years later.

PURPOSE: The literature describing the pulmonary mechanisms of increased PA-PaO2 during general anaesthesia was examined to define the role of airway closure and sub-radiological atelectasis. SOURCE: A Medline search was designed to include articles dealing with the stated purpose, which is thus selective rather than a meta-analysis. The MeSH consisted of the following words: Anesthesia: general/inhalational; Pulmonary gas exchange; Ventilation:perfusion ratio; Lung Physiology; Lung Volume measurements; Closing Volume/Capacity; Functional Residual Capacity; Atelectasis; Diaphragm. Also, Dr H. Rothen and Prof. G. Hedenstierna supplied raw data. PRINCIPAL FINDINGS: Changes in shape and dimensions of the thorax and abdomen immediately after induction of anaesthesia result in marked alterations in the efficiency of oxygenation. Three pathways can be described: increased effects of airway closure, increased low ventilation: perfusion in dependent lung zones, and frank atelectasis. The magnitude of the alterations is determined by the patients' age and body habitus. Some of the changes may carry-over into the postoperative period. The data suggest that increasing tidal volume during anaesthesia will reduce the effects of airway closure and that vital capacity breaths will re-expand atelectatic areas. CONCLUSION: Airway closure and atelectasis contribute equally to the increased ventilation: perfusion mismatching that occurs during general anaesthesia.

Humans↗
PubMed2004

Static pressure-volume curve characteristics are moderate estimators of optimal airway pressures in a mathematical model of (primary/pulmonary) acute respiratory distress syndrome.

OBJECTIVE: To study the value of objective pressure-volume characteristics for predicting optimal airway pressures and the development of atelectasis and overstretching during a structured lung volume recruitment procedure with subsequent reduction in airway pressures. METHODS: We used a mathematical model of a lung with adjustable characteristics of acute respiratory distress syndrome (ARDS) characteristics. Simulations were performed in five grades of ARDS in the presence of pure alveolar or combined alveolar-small airway closure as well complete or incomplete lung volume recruitability. For each simulation optimal end-expiratory pressure was determined. A static pressure-volume curve was constructed and objective characteristics of this curve calculated. The predictive value of these characteristics for end-expiratory atelectasis, overstretching, and optimal end-expiratory pressure was assessed. RESULTS: Simultaneous alveolar recruitment and overstretching during inflation were more pronounced than alveolar derecruitment and overstretching during deflation. End-expiratory pressure needed to prevent significant alveolar collapse in severe ARDS resulted in maximal safe tidal volumes that may be insufficient for adequate ventilation using conventional mechanical ventilatory modes. Plateau pressures well below the "upper corner point" (airway pressure where compliance decreases) resulted in significant alveolar overstretching. CONCLUSIONS: A recruitment maneuver followed by subsequent reduction in airway pressure limits end-expiratory atelectasis, overstretching, and pressure. None of the objective characteristics of the pressure-volume curve was predictive for end-expiratory atelectasis, overstretching, or optimal airway pressure.

Humans↗
PubMed2006

Management of pleural injuries during retroperitoneal surgical procedures.

PURPOSE: The necessity of a postoperative chest tube for the treatment of pneumothorax after a radical nephrectomy is controversial. MATERIALS AND METHODS: A five-year retrospective study was performed on 91 patients, having undergone a radical nephrectomy. We examined the existence and length of a pleural rent, presence of a postoperative thoracostomy tube, postoperative pneumothorax, postoperative pneumonia, postoperative atelectasis, pain scores, hemoglobin saturation, and length of hospital stay with univariate and multivariate analysis. RESULTS: Incidence of a pleural rent occurred in 29 (36%) of open radical nephrectomy cases; 4 of the 29 cases had a postoperative thoracostomy tube. There was no significant difference in hemoglobin saturation levels between cases that had no pleural rent, a pleural rent without a thoracostomy tube, and a pleural rent with a postoperative thoracostomy tube. A pleural rent without a postoperative chest tube had significantly lower rates of pain score, atelectasis, pneumonia, pleural effusion, and length of hospital stay compared to individuals with a postoperative chest tube. Patients with a chest tube had a significantly higher incidence of pain, atelectasis, pneumonia, effusion, and length of hospital stay. CONCLUSION: Iatrogenic pleural rents treated without a postoperative chest tube show a significant decrease in postoperative complications of pneumonia and atelectasis, pain score and length of hospital stay. These patients show no significant increases in postoperative complications; therefore, it appears that postoperative chest tube placement after a pleural injury occurs is of no advantage.

Chest Tubes↗
PubMed1999

Thoracic epidural anesthesia as an adjunct to general anesthesia for cardiac surgery: effects on ventilation-perfusion relationships.

OBJECTIVE: To determine the effects of thoracic epidural anesthesia (TEA) on ventilation-perfusion (VA/Q) relationships, atelectasis, and oxygenation before and after coronary artery bypass graft surgery (CABG). DESIGN: Prospective, controlled, unblinded, randomized trial. SETTING: Cardiothoracic clinic at a major university referral center. PARTICIPANTS: Twenty-eight patients undergoing elective CABG. INTERVENTIONS: Perioperative and postoperative TEA was added to general anesthesia (GA) in 14 patients, and 14 patients receiving GA alone served as controls. MEASUREMENTS AND MAIN RESULTS: VA/Q relationships were measured by the multiple inert gas elimination technique, and, 20 hours postoperatively, atelectasis was assessed by computerized tomographic scans. Arterial and mixed venous blood gases and hemodynamic variables were measured by standard techniques. TEA per se caused no change in shunt, VA/Q matching, or oxygenation. Induction of GA in the control group and induction of TEA caused similar reductions in mean arterial pressure. The TEA patients needed less morphine analgesia postoperatively and were extubated earlier. Extubation caused significant improvement in VA/Q matching. On the first postoperative day, a slight reduction in PaCO2 was seen in the TEA group, but no differences in shunt, VA/Q matching, or oxygenation compared with the GA group. Both groups showed extensive bilateral atelectasis. CONCLUSION: TEA can reduce respirator time and the need for morphine analgesics after CABG without negative effects on VA/Q matching, oxygenation, or atelectasis formation.

Adult↗
PubMed2004

Vital capacity manoeuvre in general anaesthesia: useful or useless?

As atelectasis occurs in most patients during general anaesthesia and may be one of the major causes for the development of hypoxaemia and nosocomial pneumonia, its prevention may be considered as an important objective in perioperative management. The major causative mechanisms are the loss of respiratory muscle tone, compression and gas absorption. Vital capacity manoeuvres have been proposed as a means to eliminate atelectasis in the vast majority of patients and restore normal pulmonary gas exchange during general anaesthesia. In this review we describe the pathogenesis of atelectasis in the perioperative period and discuss in the light of recent published investigations the suitability of the vital capacity manoeuvre as a tool during general anaesthesia. Reviewing the current literature, a vital capacity manoeuvre during general anaesthesia may only be useful under specific circumstances when mechanical ventilation with a high inspiratory fraction of oxygen is required or during cardiac surgery at the end of cardiopulmonary bypass to reduce the amount of atelectasis and to maintain adequate gas exchange.

Anesthesia, General↗
PubMed1998

Postextubation chest X-rays in neonates: a routine no longer necessary.

OBJECTIVES: To ascertain the incidence of postextubation atelectasis (PEA) in neonates, to delineate any objective differences between those infants with PEA and those without, and to see if any of those differences were predictive of the need for a postextubation chest X-ray (CXR). METHODS: This is a retrospective review of all infants ventilated in 1994. For each separate period of extubation the medical, physiotherapy and nursing notes were examined. Data were collected on birthweight, gestational age, duration of ventilation, age at extubation, ventilation requirements pre-extubation, pre- and postextubation arterial carbon dioxide tensions (PaCO2) and oxygen requirements, the number of episodes of bradycardia and apnoea, the pulse and respiratory rates pre- and postextubation, and the use of nasal continuous positive airway pressure (NCPAP). It was routine practice throughout 1994 for all ventilated babies to have a CXR 6 h postextubation. Each postextubation CXR was examined by one of the authors (MWD) for the presence of atelectasis and other diagnoses. PEA was defined as any atelectasis present on the postextubation CXR that was not present on the pre-extubation CXR. RESULTS: The overall incidence of any PEA was 2.5% (6/236). In those babies with PEA, the increase in oxygen requirement at 1 and 6 h postextubation was higher (change in inspired oxygen (deltaFiO2) of 0.05 vs 0.015, P=0.043 and deltaFiO2 of 0.045 vs 0.0, P=0.033, respectively). There was a higher incidence of the need for NCPAP some time after extubation (2/4 vs 9/163, P<0.001). No infant with PEA required reintubation and ventilation. CONCLUSIONS: In this nursery the incidence of PEA is low with no significant morbidity. Postextubation CXRs should be performed on only those infants who have an increase in oxygen requirement postextubation or become symptomatic with new or increasing respiratory distress, and to follow up atelectasis on the most recent pre-extubation CXR.

Humans↗
PubMed2000

Computerized tomography of the lungs and arterial oxygen tension studies during apnoea in anaesthetized young lambs.

Computerized tomography (CT) of the lungs and arterial oxygen tension studies were performed during general anaesthesia in an animal model to understand changes in pulmonary atelectasis associated with anaesthesia in children during a 2 min apnoeic period. Six anaesthetized lambs were subjected to three periods of apnoea lasting 2 min each. A series of 10 mm CT transaxial views were taken at three levels of the chest and arterial blood gases were analysed at the start of the apnoeic period (baseline) and again every 30 s during the apnoeic period. The areas of atelectasis were measured using the extended Hounsfield scale. The results confirmed that significant background atelectasis was associated with general anaesthesia as found in adult human studies, but failed to demonstrate any increase in atelectasis during the period of induced apnoea. The decline in arterial oxygen tension in this study could be explained due to simple utilization of oxygen in keeping with physiological principles.

Anesthesia, General↗
PubMed2001

[Use of a portable CT scanner for monitoring ventilated patients in an intensive care unit].

PURPOSE: Evaluation of postoperative pulmonary atelectasis using a portable computed tomography (CT) unit. MATERIAL AND METHODS: 5 spiral CT-examinations in low-dose technique were performed on each of 10 patients with partial pulmonary atelectasis after coronary bypass surgery. The patients were artificially ventilated using different levels (0 to +15 cm H2O) of positive end-exspiratory pressure (PEEP). The changes in atelectatic volumes were determined for each side. RESULTS: In 6 patients the primary volume of atelectasis was larger on the left side than on the right. Atelectatic volumes decreased with increasing PEEP. Re-expansion of atelectases was significantly (p < 0.01) better with a PEEP of +15 cm H2O. CONCLUSION: Computed tomography allows visualisation of postoperative atelectasis reliably, even in the low-dose technique. Concordantly, additional therapeutically relevant side findings can be detected compared to conventional chest X-ray. Risky patient transport becomes unnecessary.

Coronary Artery Bypass↗
PubMed1998

Sedation versus general anaesthesia in paediatric patients undergoing chest CT.

OBJECTIVE: CT of the chest in paediatric patients often requires sedation or general anaesthesia to minimize motion artefacts. Both sedation and general anaesthesia are associated with atelectasis which obscures the underlying pulmonary pathology. We conducted a prospective study to compare these two methods with respect to degree of motion artefacts and extent of atelectasis. MATERIAL AND METHODS: Nineteen patients undergoing 22 chest CT examinations were randomly selected for either sedation or general anaesthesia. The total area of atelectasis and the degree of motion artefacts were measured. RESULTS: The mean percentage of atelectasis was 6.67% for general anaesthesia and 0.01% for sedation (p = 0.01). There was no significant difference in the quality of the images between the sedation patients and the general anaesthesia patients. CONCLUSION: Whenever the clinical condition permits it, sedation rather than general anaesthesia should be given to paediatric patients undergoing chest CT.

Anesthesia, General↗