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PubMed1975

The effect of artificial ventilation on functional residual capacity and arterial oxygenation. II. Comparison of spontaneous respiration and artificial ventilation at similar arterial carbon dioxide tensions, tidal volumes and inspiratory gas flow rates.

We have compared cardiac output, gas exchange and pulmonary mechanics during spontaneous breathing and artificial ventilaton under conditions which kept PaCO2 within the normal range and maintained constant tidal volume and inspired gas flow rate. In dogs anaesthetized with pentobarbitone and ventilated with air, artificial ventilation increased VD/VT but did not reduce Q angstrom, FRC, or CL. PaO2 increased and A-aDO2 decreased during aritificial ventilation, perhaps because of a small increase in Q angstrom and a small decrease in oxygen consumption. It appears that many of the reported deleterious effects of artificial ventilation may be due to the use of other anaesthetic agents and patterns of ventilation, and to changes in PaCO2.

Anesthesia↗

PubMed2006

Respiratory load compensation during mechanical ventilation--proportional assist ventilation with load-adjustable gain factors versus pressure support.

RATIONALE: In mechanically ventilated patients respiratory system impedance may vary from time to time, resulting, with pressure modalities of ventilator support, in changes in the level of assistance. Recently, implementation of a closed-loop adjustment to continuously adapt the level of assistance to changes in respiratory mechanics has been designed to operate with proportional assist ventilation (PAV+). OBJECTIVES: The aim of this study was to assess, in critically ill patients, the short-term steady-state response of respiratory motor output to added mechanical respiratory load during PAV+ and during pressure support (PS). PATIENTS AND INTERVENTIONS: In 10 patients respiratory workload was increased and the pattern of respiratory load compensation was examined during both modes of support. MEASUREMENTS AND RESULTS: Airway and transdiaphragmatic pressures, volume and flow were measured breath by breath. Without load, both modes provided an equal support as indicated by a similar pressure-time product of the diaphragm per breath, per minute and per litre of ventilation. With load, these values were significantly lower (p<0.05) with PAV+ than those with PS (5.1+/-3.7 vs 6.1+/-3.4 cmH2O.s, 120.9+/-77.6 vs 165.6+/-77.5 cmH2O.s/min, and 18.7+/-15.1 vs 24.4+/-16.4 cmH2O.s/l, respectively). Contrary to PS, with PAV+ the ratio of tidal volume (VT) to pressure-time product of the diaphragm per breath (an index of neuroventilatory coupling) remained relatively independent of load. With PAV+ the magnitude of load-induced VT reduction and breathing frequency increase was significantly smaller than that during PS. CONCLUSION: In critically ill patients the short-term respiratory load compensation is more efficient during proportional assist ventilation with adjustable gain factors than during pressure support.

Adolescent↗

PubMed1999

Prevalence, etiologies and outcome of the acute respiratory distress syndrome among hypoxemic ventilated patients. SRLF Collaborative Group on Mechanical Ventilation. Société de Réanimation de Langue Française.

OBJECTIVE: To evaluate the prevalence and outcome of the acute respiratory distress syndrome (ARDS) among patients requiring mechanical ventilation. DESIGN: A prospective, multi-institutional, initial cohort study including 28-day follow-up. SETTINGS: Thirty-six French intensive care units (ICUs) from a working group of the French Intensive Care Society (SRLF). PATIENTS: All the patients entering the ICUs during a 14-day period were screened prospectively. Hypoxemic patients, defined as having a PaO(2)/FIO(2) ratio (P/F) of 300 mmHg or less and receiving mechanical ventilation, were classified into three groups, according to the Consensus Conference on ARDS: group 1 refers to ARDS (P/F: 200 mmHg or less and bilateral infiltrates on the chest X-ray); group 2 to acute lung injury (ALI) without having criteria for ARDS (200 < P/F </= 300 mmHg and bilateral infiltrates) and group 3 to patients with P/F of 300 mmHg or less but having exclusion criteria from the previous groups. RESULTS: Nine hundred seventy-six patients entered the ICUs during the study period, 43 % of them being mechanically ventilated and 213 (22 %) meeting the criteria for one of the three groups. Among all the ICU admissions, ARDS, ALI and group 3 patients amounted, respectively, to 6.9 % (67), 1.8 % (17) and 13.3 % (129) of the patients, and represented 31.5 %, 8.1 % and 60.2 % of the hypoxemic, ventilated patients. The overall mortality rate was 41 % and was significantly higher in ARDS patients than in the others (60 % vs 31 % p < 0.01). In group 3, 42 patients had P/F less than 200 mmHg associated with unilateral lung injury; mortality was significantly lower (40.5 %) than in the ARDS group. In the whole group of hypoxemic, ventilated patients, septic shock and severity indices but not oxygenation indices were significantly associated with mortality, while the association with immunosuppression revealed only a trend (p = 0.06). CONCLUSIONS: In this survey we found that very few patients fulfilled the ALI non-ARDS criteria and that the mortality of the group with ARDS was high.

Adult↗

PubMed2000

Effect of hypothermia on ventilation in anesthetized, spontaneously breathing rats: theoretical implications for mechanical ventilation.

OBJECTIVE: To test if hypothermia, induced by a sustained pentobarbital anesthesia, in rats can reduce ventilatory demands without compromising pulmonary gas-exchange efficiency. DESIGN: Prospective study. SETTING: Research laboratory in a hospital. SUBJECTS: One group of 11 female Sprague Dawley rats. INTERVENTIONS: The rats were anesthetized with 45 mg/kg pentobarbital, tracheostomized and intubated; their femoral veins and arteries were cannulated. After surgery, anesthesia and fluid balance were maintained (10 mg/kg per h pentobarbital, and 5 ml/kg per h saline, i.v.). Rectal temperature, mean arterial blood pressure (MAP), and heart rate (HR) were continuously monitored. The respiratory variables and gas-exchange profiles were determined at 38 degrees C (normothermia), and during stepwise hypothermia at 37, 35, 33, 31 and 29 degrees C. The arterial pressure of carbon dioxide (PaCO2), pH and arterial pressure of oxygen (PaO2) during hypothermia were corrected at body temperature. MEASUREMENTS AND RESULTS: Graded systemic hypothermia, with maintained anesthesia, produced a strong correlation between reduction in the respiratory frequency and rectal temperature (r2 = 0.55; p < 0.0001; n = 66). The minute volume was significantly reduced, starting at 35 degrees C, without significant changes in the tidal volume (repeated measures of analyses of variance followed by Dunnett multiple comparisons test). No significant changes occurred in the PaCO2, pH, PaO2, hemoglobin oxygen saturation, the calculated arterial oxygen content and estimated alveolar-arterial oxygen difference during mild hypothermia (37-33 degrees C). The PaO2, however, was significantly reduced below 31 degrees C. The MAP remained stable at different levels of hypothermia, whereas HR was significantly reduced below 33 degrees C. CONCLUSIONS: Mild hypothermia in rats, induced by a sustained pentobarbital anesthesia, reduces ventilation without compromising arterial oxygenation or acid-base balance, as measured at body temperature. Theoretically, our observations in spontaneously breathing rats imply that a combination of mild hypothermia with anesthesia could be safely utilized to maintain adequate ventilation, using relatively low minute ventilation. We speculate that such a maneuver, if applied during mechanical ventilation, may prevent secondary pulmonary damage by allowing the use of lower ventilator volume-pressure settings.

Adjuvants, Anesthesia↗

PubMed1991

Comparison of different rates of artificial ventilation for preterm infants ventilated beyond the first week of life.

The effect on blood gases of different ventilator rates in preterm infants ventilated beyond the first week of life was assessed. Seventeen infants, median gestational age 25 weeks, were studied at median postnatal age of 11 days. The infants were ventilated through a set sequence of rates: 30, 60, 30, 100 and 30 breaths per min (bpm), each rate being maintained for 20 min. Peak and positive end expiratory pressure and I:E ratio (1:1) were unchanged at each rate and mean airway pressure was kept constant by altering flow as necessary. No significant change in oxygenation was demonstrated at either rates of 60 or 100 bpm compared to 30 bpm. PaCO2 levels were, however, significantly reduced at 60 bpm (P less than 0.001) compared to 30 bpm; but this improvement in PaCO2 was not seen at 100 bpm. These results suggest that increasing ventilator rate higher than 60 bpm in the majority of infants ventilated after the first week of life is not advantageous.

Bronchopulmonary Dysplasia↗

PubMed1983

Comparison of high-frequency jet ventilation and conventional mechanical ventilation in a meconium aspiration model.

Ten adult cats received alternately high-frequency jet ventilation and conventional mechanical ventilation after aspirating 2 ml/kg 25% human meconium in saline. Equivalent mean airway pressures were maintained during the hourly ventilator changes. Aortic pressures, pulmonary artery pressures, and central venous pressures were continuously monitored. Cardiac outputs were measured, and pulmonary and systemic vascular resistances, intrapulmonary shunts, and alveolar arterial oxygen gradients were determined at regular intervals. During the first hour after aspiration, AaDO2 and Qs/Qt were lower during HFJV (P less than 0.05); PVR and Pa were always higher during HFJV (P less than 0.05). Overall, PVR, Pa, AaDO2, and Qs/Qt rose during HFJV; these changes occurred at equivalent Paw within 15 minutes of each ventilator change (P less than 0.05). In this meconium aspiration model, conventional mechanical ventilation was the superior form of ventilatory therapy.

Airway Resistance↗

PubMed2001

The respiratory system during resuscitation: a review of the history, risk of infection during assisted ventilation, respiratory mechanics, and ventilation strategies for patients with an unprotected airway.

The fear of acquiring infectious diseases has resulted in reluctance among healthcare professionals and the lay public to perform mouth-to-mouth ventilation. However, the benefit of basic life support for a patient in cardiopulmonary or respiratory arrest greatly outweighs the risk for secondary infection in the rescuer or the patient. The distribution of ventilation volume between lungs and stomach in the unprotected airway depends on patient variables such as lower oesophageal sphincter pressure, airway resistance and respiratory system compliance, and the technique applied while performing basic or advanced airway support, such as head position, inflation flow rate and time, which determine upper airway pressure. The combination of these variables determines gas distribution between the lungs and the oesophagus and subsequently, the stomach. During bag-valve-mask ventilation of patients in respiratory or cardiac arrest with oxygen supplementation (> or = 40% oxygen), a tidal volume of 6-7 ml kg(-1) ( approximately 500 ml) given over 1-2 s until the chest rises is recommended. For bag-valve-mask ventilation with room-air, a tidal volume of 10 ml kg(-1) (700-1000 ml) in an adult given over 2 s until the chest rises clearly is recommended. During mouth-to-mouth ventilation, a breath over 2 s sufficient to make the chest rise clearly (a tidal volume of approximately 10 ml kg(-1) approximately 700-1000 ml in an adult) is recommended.

History, Ancient↗

PubMed2003

[Ventilation in special situations. Mechanical ventilation in status asthmaticus].

The indications for mechanical ventilation in status asthmaticus are cardiopulmonary arrest, significant alteration of consciousness, respiratory exhaustion, and progressive respiratory insufficiency despite aggressive bronchodilator treatment. In mechanical ventilation for status asthmaticus, a specific strategy directed at reducing dynamic hyperinflation must be used, with low tidal volumes and long expiratory times, achieved by diminishing respiratory frequency. This ventilatory pattern produces permissive hypercapnia, which is generally well tolerated with suitable sedation. The best methods for detecting and/or controlling dynamic hyperinflation in ventilated patients with status asthmaticus are the flow/time and flow/volume respiratory curves, pulmonary volume at the end of inspiration, and the pressure plateau. In addition to mechanical ventilation the child must receive sedation with or without a muscle relaxant to prevent barotrauma and accidental extubation. Bronchodilator treatment with beta-adrenergic agonists, methyl-prednisolone, and intravenous aminophylline are also required. A combination of inhaled salbutamol and nebulized ipratropium in the inspiratory branch of the ventilator should be used in patients in whom this treatment is effective. Currently there is insufficient evidence on the efficiency of other treatments in status asthmaticus and these should be used as rescue treatments.

Child↗

PubMed2003

[Ventilation in special situations. Mechanical ventilation in bronchiolitis].

Bronchiolitis is a prevalent viral disease in infants. Many of these infants require hospital admission and mechanical ventilation due to respiratory failure or apnea. The clinical and pathophysiological spectrum of this disease can range from two extremes, obstructive and restrictive disease, on which the indication for mechanical ventilation and the modality used should be based. Non-invasive ventilation is especially indicated in both obstructive and hypoxemic restrictive patterns and a pressure-controlled modality is recommended. In obstructive patterns, air trapping must be monitored, while in restrictive patterns the addition of positive end-expiratory pressure (PEEP) is indicated. High-frequency oscillatory ventilation is indicated in restrictive patterns with sever hypoxemia despite conventional ventilatory support or in cases of significant air leak syndromes. In all cases, a permissive hypercapnia strategy is recommended to prevent barotrauma. Sedation and muscle relaxation should be considered to facilitate adaptation to the ventilator and to try to limit the risks of air trapping, air leak, and barotrauma.

Bronchiolitis↗

PubMed2003

[Ventilation in special situations. Mechanical ventilation in acute respiratory distress syndrome/acute pulmonary lesion].

Acute respiratory distress syndrome (ARDS), which was first described by Ashbaugh in 1967, consists of acute hypoxemic respiratory failure (PaO2/FiO2< or =200) associated with bilateral infiltrates on the chest radiograph caused by noncardiac diffuse pulmonary edema. Although ARDS is of multiple etiology, pulmonary or extrapulmonary injury can produce systemic inflammatory response that perpetuates lung disturbances once the initial cause has been eliminated. Most patients with ARDS require mechanical ventilation. Currently, the old standard is conventional ventilation optimized to protect against ventilator-associated lung injury. Other mechanical ventilation strategies such as high-frequency oscillatory ventilation, which is also based on alveolar recruitment and adequate lung volume, can be useful alternatives. In this review, the level of evidence for other therapies, such as prone positioning, nitric oxide and prostacyclin inhalation, exogenous surfactant, and extracorporeal vital support techniques are also analyzed.

Humans↗

PubMed2003

[Ventilation in special situations. Mechanical ventilation in congenital cardiopathies and pulmonary hypertension].

The cardiovascular and respiratory systems act as a functional unit. Mechanical ventilation modifies pulmonary volumes, which generates changes in autonomic nervous system reactivity and provokes tachy- or brady-cardia (depending on the tidal volume used). Mechanical ventilation also decreases cardiac filling volumes (pre-load) and alters pulmonary vascular resistances. In addition, intrathoracic pressures are enlarged, which usually produces a decrease in right atrium filling and an increase in right ventricle afterload. If coronary flow is impaired, myocardial contractility is reduced. However, if cardiac failure is present, mechanical ventilation is especially beneficial because it corrects hypoxia and respiratory acidosis, decreases the work of breathing, and improves stroke volume. Mechanical ventilation in congenital heart diseases is indicated either as lifesaving support or as physiopathological treatment to modify the ratio between pulmonary and systemic flow. As a general rule, if excessive pulmonary blood flow is present, the aim of respiratory support is to increase pulmonary vascular resistance by using high levels of airway pressure and even by delivering FiO2<21%. When there is low pulmonary flow, the lowest possible intrathoracic pressures should be used, especially in cases of pulmonary hypertension, which will also require high FiO2. However, mechanical ventilation has adverse effects and consequently it must be stopped as early as possible, once the child is stable and requires minimal cardiopulmonary support. Weaning can even be performed in the operating room, when the surgical procedure is finished. When this is not possible, weaning should be performed in the pediatric intensive care unit. Because there are no criteria for successful withdrawal of mechanical support in congenital heart disease, general pediatric criteria should be used.

Child↗

PubMed1986

Degree of dependence on the ventilator according to sleep states in artificially ventilated premature infants.

Polygraphic recordings were performed in 14 sleeping premature infants receiving ventilation for respiratory distress syndrome. All were clinically stabilized, with normal EEG and neurologic status and differentiated sleep states (coded according to EEG and REM criteria). They all had two respiratory patterns: passive, completely dependent on the ventilator, and active, with autonomous respiratory movements and/or inspiratory diaphragmatic activity added to passive respiration. We found that in infants ventilated at the rate of 18-54/min, respiration was more active and autonomous in active REM sleep and more passive and dependent on the machine in quiet NREM sleep (P less than 0.005). Within the limits of the values observed in our study, differences between sleep states were not due to other factors that could possibly interfere with and modify the degree of respiratory autonomy. We found no significant correlation between the percentage of time passed with active respiration on one hand and age (gestational, postnatal, conceptional) or diagnostic or physical parameters of artificial ventilation and blood gas levels on the other hand. Our results suggest that in artificially ventilated but neurologically normal premature infants, differences between respiratory control in both sleep states exist as early as 28 weeks conceptional age (lower limit of our study).

Age Factors↗

PubMed1985

Acid-base changes and ventilator mode during maintenance ventilation.

Assist-control ventilation was compared to intermittent mandatory ventilation (IMV) for respiratory support of 35 patients without known respiratory disease, who had undergone coronary bypass surgery. Spontaneous respiratory rates and minute ventilation did not differ significantly between the two groups. Blood gas samples obtained during the assist-control mode had a significantly lower PaCO2 and higher pH than blood gases measured during high-rate IMV. There were six cases of severe alkalemia during assist-control ventilation, all respiratory in origin. These were attributable to the higher respiratory-rate settings and the extra respirator-delivered tidal volumes when spontaneous rates were higher than the set rates. IMV was associated with fewer ventilator-induced acid-base changes.

Acidosis, Respiratory↗

PubMed1993

A new ventilation inhomogeneity index from multiple breath indicator gas washout tests in mechanically ventilated patients.

OBJECTIVES: a) To determine the validity of a new method to analyze indicator gas washout tests on mechanically ventilated patients. This method takes into account the difference between the end-expiratory gas fraction and the mean gas fraction in the lung and provides the end-expiratory lung volume and a new index of ventilation inhomogeneity called volumes regression index. b) To determine the validity of this index as a predictor of chronic obstructive pulmonary disease. c) To compare this index with the moment ratio index and Becklake index. DESIGN: Prospective study of diagnostic test. Criterium standards: Closed-circuit indicator gas dilution technique and Tiffeneau index. SETTING: Surgical intensive care unit of a university hospital. PATIENTS: A total of 38 mechanically ventilated postoperative patients, divided into two groups: the obstructive group (n = 21) and the nonobstructive group (n = 17), based on their preoperative lung function. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: a) The mean coefficient of variation of all lung volume measurements in a group of nine healthy volunteers was 5%, and the difference between this technique and the closed-circuit helium dilution measurements was -2 +/- 5%. In patients, the mean coefficient of variation of the lung volume measurements was 3.5%. The volumes regression index was measured as 0.02 +/- 0.04 in a dummy lung, 0.37 +/- 0.08 in the healthy volunteers, 0.64 +/- 0.23 in the nonobstructive patients, and 1.1 +/- 0.3 in the obstructive patients. The volumes regression index provided a better correlation (r2 = .46) with preoperatively determined Tiffeneau index than the Becklake index (r2 = .11) or the moment ratio index (r2 = .18). CONCLUSION: The proposed technique provides a means for accurate measurement of the end-expiratory lung volume and the amount of ventilation inhomogeneity in mechanically ventilated intensive care unit patients.

Adult↗

PubMed1997

How to use articles about harm: the relationship between high tidal volumes, ventilating pressures, and ventilator-induced lung injury.

BACKGROUND: Intensivists commonly encounter patients who may be inadvertently harmed by critical care interventions. This article is designed to guide clinicians in the evaluations of an individual article assessing a question of harm, as well as the sum of multiple pieces of evidence. OBJECTIVES: To assess the vaidity of a group of articles about the relationship between high tidal volumes and ventilating pressures on ventilator-induced lung injury; to interpret the results of these studies; and to consider whether they apply in practice. DATA SOURCES: Issues of harm are sometimes measured in randomized trials, but are evaluated more often in myriad observational studies. DATA EXTRACTION: We use critical appraisal guides for experimental studies (e.g., randomized trials) and observational studies (e.g., cohort studies, case-control studies and case series) that evaluate the potentially harmful exposure of high tidal volumes and ventilating pressures. This involves assessing the validity of the research, then determining the strength of association between the putative harmful exposure and adverse outcomes. These study designs and their interpretation using relative risks and odds ratios are reviewed. Finally, the relevance of this information (or lack thereof) to clinical practice needs to be determined. DATA SYNTHESIS: Examining these studies individually and in totality, there appears to be a relationship between high tidal volumes and ventilating pressures, although the strength of inference from this research is limited by design issues and sample sizes. CONCLUSIONS: Critically appraising a body of literature is more challenging than evaluating a single study, but often gives a broader view of the available evidence. Future large, rigorous, randomized trials of different approaches to mechanical ventilation will help to advance our understanding and to better inform our practice.

Clinical Trials as Topic↗

PubMed2002

In vitro evaluation of aerosol bronchodilator delivery during noninvasive positive pressure ventilation: effect of ventilator settings and nebulizer position.

OBJECTIVE: Respiratory failure due to exacerbation of obstructive lung disease has been successfully treated with noninvasive positive pressure ventilation (NPPV). However, there have been no reports of factors affecting aerosol delivery during NPPV. Our objective was to determine the effect of ventilator settings and nebulizer position on albuterol delivery during NPPV. DESIGN: Bench model study. SETTING: University laboratory. SUBJECTS: None. INTERVENTIONS: A Respironics BiPAP S/T-D30 with a standard circuit was attached to a lung model simulating spontaneous breathing. Inspiratory/expiratory pressures of 10/5, 15/5, 20/5, 15/10, 20/10, and 25/10 cm H2O were tested at respiratory rates of 10 and 20/min. A nebulizer was filled with 5 mg of albuterol in 4 mL of solution, driven with 8 L/min oxygen, and placed at either a proximal (ventilator outlet) or distal (between leak port and lung model connection) position. Albuterol delivery was estimated by measuring the amount of the albuterol collected on a filter placed at the inlet of the lung model. MEASUREMENT AND MAIN RESULTS: Albuterol delivery varied from 5.2 +/- 0.4% to 24.5 +/- 1.3% of the nominal dose and was significantly affected by the position of the nebulizer, respiratory rate, and BiPAP settings (p <.001 in each case). The greatest albuterol delivery was observed with the nebulizer operating at the distal position and a respiratory rate of 20/min. At this respiratory rate and nebulizer placement, albuterol delivery increased with increasing inspiratory pressure levels and decreased as expiratory pressure levels were increased. Nebulizer flow did not affect function of the ventilator. CONCLUSIONS: At optimum nebulizer position (between the leak port and patient connection) and ventilator settings (high inspiratory pressure and low expiratory pressure), as much as 25% of the nominal albuterol dose may be delivered during NPPV.

Aerosols↗

PubMed1985

Comparison of conventional mechanical ventilation and synchronous independent lung ventilation (SILV) in the treatment of unilateral lung injury.

Eight patients presenting with severe unilateral pulmonary injury responded poorly to conventional mechanical ventilation. Synchronous independent lung ventilation (SILV) was employed to provide support of ventilation and oxygenation without creating the ventilation/perfusion (V/Q) mismatch observed during conventional ventilation. All patients demonstrated improved oxygenation (mean increase, 80 torr) during SILV with the FIO2 unchanged from previous therapy. Invasive hemodynamic monitoring in five of eight patients showed no difference in the commonly measured cardiopulmonary parameters with the two forms of mechanical ventilation. Peak inspiratory pressure (PIP), continuous positive airway pressure (CPAP), and pressure change secondary to tidal volume delivery to the uninvolved lung were significantly less during SILV. SILV is an effective method of improving oxygenation in patients with severe unilateral pulmonary injury.

Adolescent↗

PubMed1997

Evaluation of pulmonary ventilation and diaphragmatic movement in idiopathic scoliosis using radioaerosol ventilation scintigraphy.

Regional distribution of lung ventilation and diaphragmatic movement were evaluated using a non-invasive scintigraphic method in patients with idiopathic scoliosis. Twenty-four non-smoking patients aged 20 +/- 9 years (mean +/- S.D.), all with a right convex dorsal curve (mean Cobb's angle of 65.1 +/- 26.4 degrees), underwent lung ventilation scintigraphy after inhalation of 99Tcm-labelled human albumin microspheres. The distribution of the inhaled aerosol was assessed and scored based on four scintigraphic patterns, ranging from homogeneous distribution (score = 1) to diffuse severe hypoventilation (score = 4). Diaphragmatic movement, evaluated in 11 of the 24 patients, was assessed using an index (DM-Index) computed for each hemi-diaphragm by the normalization and subtraction of two digital scans obtained during maximal inspiration and expiration respectively. The left lung, situated on the concave side of the scoliotic curve, showed a more uneven distribution of ventilation (scintigraphic score: 2.62 +/- 1.17 vs 1.50 +/- 1.02, P < 0.01) and a reduced hemi-diaphragm movement (DM-Index: 29.2 +/- 4.0 vs 35.9 +/- 2.9, P < 0.001). A significant inverse correlation was found between Cobb's angle and both the right and left DM-Index (r = -0.82 and -0.66 respectively). In a stepwise multiple-regression analysis, the scintigraphic score correlated significantly with the functional index of distribution of inspired gas (IDI) derived from the multiple-breath nitrogen washout curve (P = 0.02). We conclude that lung ventilation scintigraphy provides information on the regional distribution of ventilation and on diaphragmatic movement in idiopathic scoliosis. The pulmonary function derangements in scoliotic patients were mainly localized in the lung on the concave side of the scoliotic curve and were related to the severity of the spinal curvature.

Adult↗