Search

An extensive topical negative pressure wound therapy (NPWT) from the abdominal to chest walls in neonates may decrease the compliance of the chest wall. Therefore, it is important to monitor respiratory function carefully during the procedure.

Objective To evaluate the effect of two doses of fentanyl upon chest wall rigidity of dogs anesthetized at equipotent doses of isoflurane [1.3 minimum alveolar concentration (MACISO) of each dose of fentanyl]. Study design Prospective crossover randomized study. Animals A group of eight male Beagle dogs, approximately 1 year old and weighing 12.1 ± 1.6 kg (mean ± standard deviation). Methods The dogs were anesthetized with isoflurane and instrumented for the measurement of esophageal pressure (PESO), flow ( V ˙ ) and volume ( V ). Chest wall elastance (ECW) was estimated by multiple linear regression of the model. PESO(t) = V ˙ (t) × RCW + V(t) × ECW + EEPESO where t is time, RCW is chest wall resistance and EEPESO is end-expiratory PESO. Chest wall compliance (CCW) was calculated as 1/ECW and normalized to the body weight of each dog (mL cmH2O−1 kg−1). Anesthesia was maintained at 1.3 MACISO for at least 15 minutes and CCW recorded (CCW-ISO). The dogs were randomly assigned to the lower fentanyl dose [loading dose (33 μg kg−1) and infusion (0.2 μg kg−1 minute−1)] or the higher fentanyl dose [loading dose (102 μg kg−1) and infusion (0.8 μg kg−1 minute−1)]. After 60 minutes of fentanyl infusion, CCW was recorded for each dose (CCW-FENT). During fentanyl infusion, the dogs were maintained at equipotent doses of isoflurane (1.3 MACISO for each fentanyl dose). A two-way analysis of variance followed by a Bonferroni test was used to compare CCW-ISO and CCW-FENT in both treatments and CCW-FENT between treatments. A p value Results Neither of the fentanyl doses decreased CCW and there was no difference in CCW-FENT between doses. Conclusions and clinical relevance Fentanyl at the studied doses did not result in chest wall rigidity in dogs anesthetized with equipotent doses of isoflurane (1.3 MACISO).

Understanding the respiratory mechanics of ARDS patients is crucial to avoid ventilator-induced lung injury (VILI), and this is much more challenging if not only lung compliance is altered but the whole compliance of the respiratory system is abnormal, as in obese patients. We face this problem daily in the ICU, and to optimize ventilation, we estimate respiratory mechanics using an oesophageal balloon. The balloon position is crucial to assess reliable values. In the present technical note, we describe the use of echocardiography to confirm the correct position of this instrument.

The modified Campbell diagram provides one of the most comprehensive assessments of the work of breathing (Wb) during exercise, wherein the resistive and elastic work of inspiration and expiration are quantified. Importantly, a necessary step in constructing the modified Campbell diagram is to obtain a value for chest wall compliance (CCW). To date, it remains unknown whether estimating or directly measuring CCW impacts the Wb, as determined by the modified Campbell diagram. Therefore, the purpose of this study was to evaluate whether the components of the Wb differ when the modified Campbell diagram is constructed using an estimated versus measured value of CCW. Forty-two participants ( n = 26 men, 16 women) performed graded exercise to volitional exhaustion on a cycle ergometer. CCW was measured directly at rest via quasistatic relaxation. Estimated values of CCW were taken from prior literature. The measured value of CCW was greater than that obtained via estimation (214 ± 52 mL/cmH2O vs. 189 ± 18 mL/cmH2O; P < 0.05). At modest-to-high minute ventilations (i.e., 50–200 L/min), the inspiratory elastic Wb was greater and expiratory resistive Wb was lower, when modified Campbell diagrams were constructed using estimated compared with measured values of CCW ( P = 0.001). These differences were however small and never exceeded ±5%. Thus, although our findings demonstrate that estimating CCW has a measurable impact on the determination of the Wb, its effect appears relatively small within a cohort of healthy adults during graded exercise.

Congenital absence of the sternum is a rare chest wall malformation resulting from the failure of midline fusion during embryonic development. It is a potentially life-threatening congenital midline defect. Only sporadic cases have been reported in literature. The abnormality can cause significant morbidity, and like other congenital anomalies can have associated defects. Repair of congenital absence of the sternum should ideally be undertaken in the neonatal period when the chest wall is highly compliant, and hence, primary closure can thus be achieved without significant cardiopulmonary compression. As the patient ages, chest wall compliance decreases and closure will become progressively difficult as venous return and lung compliance are increasingly compromised. We report a case of congenital absence of the sternum as it is very rare and because it was successfully operated in a neonate period.

The driving pressure of the respiratory system has been shown to strongly correlate with mortality in a recent large retrospective ARDSnet study. Respiratory system driving pressure [plateau pressure-positive end-expiratory pressure (PEEP)] does not account for variable chest wall compliance. Esophageal manometry can be utilized to determine transpulmonary driving pressure. We have examined the relationships between respiratory system and transpulmonary driving pressure, pulmonary mechanics and 28-day mortality.Fifty-six patients from a previous study were analyzed to compare PEEP titration to maintain positive transpulmonary end-expiratory pressure to a control protocol. Respiratory system and transpulmonary driving pressures and pulmonary mechanics were examined at baseline, 5 min and 24 h. Analysis of variance and linear regression were used to compare 28 day survivors versus non-survivors and the intervention group versus the control group, respectively.At baseline and 5 min there was no difference in respiratory system or transpulmonary driving pressure. By 24 h, survivors had lower respiratory system and transpulmonary driving pressures. Similarly, by 24 h the intervention group had lower transpulmonary driving pressure. This decrease was explained by improved elastance and increased PEEP.The results suggest that utilizing PEEP titration to target positive transpulmonary pressure via esophageal manometry causes both improved elastance and driving pressures. Treatment strategies leading to decreased respiratory system and transpulmonary driving pressure at 24 h may be associated with improved 28 day mortality. Studies to clarify the role of respiratory system and transpulmonary driving pressures as a prognosticator and bedside ventilator target are warranted.

Background: Higher chest compression release velocity (CCRV) is associated with better outcomes after OHCA. Patient age and gender have been associated with variations in chest wall compliance and compressibility which may impact outcomes. Hypothesis: To evaluate the association between CCRV and OHCA patient age, weight, and gender. Methods: Observational study of prospectively collected OHCA quality improvement data in two suburban EMS agencies in Arizona between 10/1/2008 and 12/31/2016. Patient age and weight were categorized into quartiles for the analysis. CCRV was summarized at each level of the categorical variable by median and inter-quartile range (IQR), and was then compared between different levels by the Kruskal-Wallis test. Results: During the study period, 2,661 OHCA cases were treated. After exclusion criteria, 1,140 cases remained for analysis. Median duration of compressions was 8.70 minutes. Mean CCRV was negatively correlated with age and positively correlated with weight (Table). Male patients exhibited a greater mean CCRV compared to female patients [344.4 mm/s (IQR 307.3-384.6) vs. 331.5 (285.3-385.5), p=0.0133]. Conclusion: Patient characteristics including younger age, male gender, and increased weight were associated with a higher CCRV during OHCA resuscitation.

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency medicine 2016. Other selected articles can be found online at http://www.biomedcentral.com/collections/annualupdate2016. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Avaliou-se a função respiratória de 40 parkinsonianos (P), entre 50 e 80 anos, nos estágio I a III da Escala de Hoehn e Yahr e de 40 não parkinsonianos (NP), com características semelhantes. A amplitude torácica de 1,8±0,8 cm nos P foi menor que 4,3±1,0 cm nos NP (p=0,00001), assim como os percentuais das capacidades vital e vital forçada de 66,8±20,3% e 69,6±22,2% nos P e de 82,3±15,7% e 82,7±16,6% nos NP (p=0,00001 e p=0,0023). Apresentaram-se equivalentes as pressões inspiratória e expiratória máximas, de 33,5±12,7 cmH2O e 36, 3±17,8 cmH2O nos P e de 37,0±12,2 cmH2O e 43,1±16,6 cmH2O nos NP (p=0,1753 e 0,0398), o volume do 1º segundo da curva expiratória forçada de 71,3±25,6% nos P e 80,6±23,6% nos NP (p=0,0899) e o percentual da capacidade vital forçada expirada em um segundo, de 104,5±19,9% nos P e 97,4±22,8% nos NP (p=0,1234). Os parkinsonianos evidenciaram restrição respiratória e diminuição de amplitude torácica, sem alteração da força muscular respiratória. We studied 40 parkinsonian patients (P), mean age 50-80 years, with Hoehn and Yahr stages I-III and 40 no parkinsonian patients (NP), with similar characteristics. The results of the thoracic amplitude was 1,8±0,8cm of P that showed a reduction to 4,3±1,0 cm of NP (p=0,00001), the vital capacity and forced vital capacity, 66,8±20,3% and 69,6±22,2% of P was decreased that 82,3±15,7% and 82,7±16,6% of NP (p=0,00001 and p=0,0023). There was not difference among the maximal inspiratory and expiratory mouth pressures, 33,5±12,7 cmH2O and 36,3±17,8 cmH2O of P and 37,0±12,2 cmH2O and 43,1±16,6 cmH2O of NP (p=0,1753 and p=0,0398), the forced expiratory volume in 1 second, 71,3±25,6% of P and 80,6±23,6% of NP (p=0,0899), and the forced expiratory volume in 1 second/ forced vital capacity, 104,5±19,9% of P and 97,4±22,8% of NP (p=0,1234). The parkinsonian patients present restrictive pulmonary dysfunction, low chest wall compliance and the respiratory muscle strenght do not decreased.

Study objective: To assess the clinical use of measurements of lung-chest wall compliance (Cstat) using an optional software program integrated into a microprocessor-controlled ventilator during the continuous axial rotation of mechanically ventilated patients. Design and patients: Twelve patients with severe respiratory failure were placed on the Rotorest® Kinetic Treatment Table, rotated continuously on both sides and ventilated in pressure-controlled mode. Blood gases and lung-chest wall compliance were quantified using ventilator computer software while rotating the patients in stepwise increments to the left and right side. PaO2 and PaCO2 values were compared to static compliance by regression analysis. Results: During continuous rotation therapy (kinetic therapy) and ventilation in pressure-controlled mode, lung mechanics changed rapidly as a result of turning the patients to the left or right dependent position. The degree of change was influenced by the severity and dimension of the lung disease (...

Development of chest wall stiffness between infancy and adulthood has important consequences for respiratory system function. To test the hypothesis that there is substantial stiffening of the chest wall in the first few years of life, we measured passive chest wall compliance (Cw) in 40 sedated humans 2 wk-3.5 yr old. Respiratory muscles were relaxed with manual ventilation applied during the Mead-Whittenberger technique. Respiratory system compliance (Crs) and lung compliance (Cl) were calculated from airway opening pressure, transpulmonary pressure, and tidal volume. Cw was calculated as 1/Cw = 1/Crs - 1/Cl during manual ventilation. Mean Cw per kilogram in infants < 1 yr old was significantly higher than that in children > 1 yr old (2.80 +/- 0.87 vs. 2.04 +/- 0.51 ml.cmH2O–1.kg-1; P = 0.002). There was an inverse linear relationship between age and mean Cw per kilogram (r = -0.495, slope -0.037; P < 0.001). In subjects with normal Cl during spontaneous breathing, Cw/spontaneous Cl was 2.86 +/- 1.06 in infants < 1 yr old and 1.33 +/- 0.36 in older children (P = 0.005). We conclude that in infancy the chest wall is nearly three times as compliant as the lung and that by the 2nd year of life chest wall stiffness increases to the point that the chest wall and lung are nearly equally compliant, as in adulthood. Stiffening of the chest wall may play a major role in developmental changes in respiratory system function such as the ability to passively maintain resting lung volume and improved ventilatory efficiency afforded by reduced rib cage distortion.

Objetivo: Analizar la correlación entre la presión intraabdominal e intratorácica en pacientes con sospecha de hipertensión intraabdominal (HIA). Diseño: Estudio prospectivo observacional de una cohorte. Ámbito: Unidad de medicina intensiva polivalente de un hospital universitario. Pacientes: Se incluyó a 27 pacientes medicoquirúrgicos dependientes de ventilación mecánica controlada por fallo respiratorio agudo y con factores de riesgo de hipertensión intraabdominal. Principales variables: Medimos las presiones intraabdominal (PIA), esofágica (Peso) y de la vía aérea en condiciones estáticas (est) y dinámicas (din). Calculamos la distensibilidad del sistema respiratorio (Csr), pulmón (Cp) y pared torácica (Cpt). Resultados: En 10 pacientes la PIAest fue mayor de 12mmHg (HIA, PIAest, 14±2 [12-21] mmHg) y en el resto fue normal (n=17; PIAest, 8±2 [3-11] mmHg). La Pesoest fue 11±5 (2-27) y Pesodin, 7±4 (2-24) cmH2O. Considerando la presencia o no de HIA, Pesoest fue 9±4 vs. 7±3cmH2O (p=0,2) y Pesodin, 6±2 vs. 4±3cmH2O (p=0,3), respectivamente. La correlación de Pesoest y din con PIAest fue 0,5 (p=0,003) y 0,4 (p=0,03), respectivamente. Los componentes de la distensibilidad del sistema respiratorio estaban disminuidos (Csr, 31±8; Cp, 52±22; Cpt, 105±50ml/cmH2O), Cpt fue significativamente más baja en los pacientes con HIA (81±31 vs. 118±55ml/cmH2O; p=0,02). El coeficiente de correlación entre la PIAest y Cpt fue -0,7 (p12mmHg (IAH, IAPst, 14±2 [12-21] mmHg), while in the rest the pressure proved normal (n=17; IAPst, 8±2 [3-11] mmHg). Peso st was 11±5 (2-27) and Peso dyn 7±4 (2-24) cmH2O. Depending on the presence or absence of IAH, Peso st was 9±4 vs 7±3cmH2O (p=0.2) and Peso dyn 6±2 vs 4±3cmH2O (p=0.3), respectively. The correlation between Peso st and dyn with IAPst was 0.5 (p=0.003) and 0.4 (p=0.03), respectively. The compliance components were decreased (Crs, 31±8; Cl, 52±22 and Ccw, 105±50ml/cmH2O); Ccw was significantly lower in patients with IAH (81±31 vs 118±55ml/cmH2O; p=0.02). The correlation coefficient between IAPst and Ccw was -0.7 (p

Impulse Oscillometry (IOS) measurements of respiratory impedance were obtained from young asthmatic children pre- and post-bronchodilator (pre- and post-BD). Mead’s model of respiratory impedance was then used to estimate the central inertance (I), central and peripheral resistances (R c , R p ), and lung, chest wall, bronchial, and extrathoracic compliances (C l , C w , C b , C e ) by least-squares-optimal fitting to the IOS data. This typically produced multiple near-optimal solutions, with estimates ofC l and C w that varied by 2 to 3 orders of magnitude and were also several orders of magnitude larger than expected physiological values; up to 515,000 L/kPa for C l , and 81,138 L/kPa for C w . We then performed constrained optimization of pre-BD data with C w fixed at 0.50 L/kPa and C l fixed at 0.38 L/kPa, which yielded averaged least-squares (LS) error 44.1% larger than for unconstrained optimization, while R c , I, R p , C b and C e changed by an average of 12.5%, 32.2%, 25.1%, 26.7% and 2.6x1011%, relative to unconstrained values; the large change in C e due to it becoming negligible in about 25% of the results. Next, constrained optimization of post-BD data with C w = 0.5 L/kPa, C l = 0.38 L/kPa, resulted in an averaged LS error 39.4% larger than for unconstrained optimization, while R c , I, R p , C b and C e changed by an average of 1.7x1012%, 23.4%, 29.1%, 36.9% and 3.5x1011%, relative to unconstrained values. Neglecting two results with unphysiologically small R c reduced the average change in R c to 19.1% without significantly impacting the average change of the other parameters. Constrained optimization of pre-BD data and then post-BD data with C w = 0.5 L/kPa, C l = 0.33 L/kPa, resulted in similar changes to total LS error and remaining parameters. We conclude that the Mead model’s impedance and parameter estimates (except C e , unimportant in asthma) for young asthmatic children are relatively insensitive to C l and C w .

Impulse Oscillometry (IOS) measures respiratory resistance and reactance from 5 to 35 Hz. These data were obtained from 2 groups of adults enrolled in a study of IOS compared to other lung function testing methods: 1 group of 10 adults with no identifiable respiratory disease and 1 group of 10 adults with varying degrees of COPD. We used Mead’s model of the respiratory system to derive parameter estimates of central inertance (I), central and peripheral resistances (R c , R p ), and lung, chest wall, bronchial, and extrathoracic compliances (C l , C w , C b , C e ) by least-squares-optimal fitting to the IOS data. This procedure typically produced multiple optimal solutions, with estimates ofC l and ofC w that varied by 2 to 3 orders of magnitude and were several orders of magnitude larger than expected physiological values, up to 8.6x105 L/kPa for C l and 2.6x105 L/kPa for C w . We then performed constrained optimization of normal adult data with both C l and C w parameters fixed at 2 L/kPa, which produced a group-averaged LS error that was 19.3% larger than for unconstrained optimization: R c , I, R p , C b and C e parameters changed by 0.99%, 1.76%, 22.0%, 11.9% and 10.6%, respectively. Constrained optimization of the COPD adults data with the C w fixed at 2 L/kPa and C l fixed first at 1.5 L/kPa and then at 1.1 L/kPa produced group-averaged LS errors that were 23.8% larger and 23.6% larger, respectively, than for unconstrained optimization: R c , I, R p , C b and C e parameters changed by 2.12%, 4.88%, 18.5%, 6.46% and 25.5%, respectively, for C l = 1.5 L/kPa; they changed by 1.64%, 4.30%, 18.4%, 6.64% and 18.5%, respectively, for C l = 1.1 L/kPa, all relative to the unconstrained case. We conclude that the Mead model’s impedance and its parameter estimates for normal and COPD adults are relatively insensitive to the C l and C w parameters.

Chest wall mechanics was studied in four subjects on changing gravity in the craniocaudal direction (Gz) during parabolic flights. The thorax appears very compliant at 0 Gz: its recoil changes only from −2 to 2 cmH2O in the volume range of 30–70% vital capacity (VC). Increasing Gz from 0 to 1 and 1.8 Gzprogressively shifted the volume-pressure curve of the chest wall to the left and also caused a fivefold exponential decrease in compliance. For lung volume z than from 1 to 1.8 Gz. For a volume from 30 to 70% VC, the effect is inspiratory going from 0 to 1 Gz but expiratory from 1 to 1.8 Gz. For a volume greater than ∼70% VC, gravity always has an expiratory effect. The data suggest that the chest wall does not behave as a linear system when exposed to changing gravity, as the effect depends on both chest wall volume and magnitude of Gz.

Chest wall compliance (C w ) was measured in 59 conscious standing calves, aged six to 162 days, which were breathing air spontaneously through a face mask. The airways were occluded at the end of inspiration in order to elicit the Hering-Breuer reflex, the effectiveness of which was ensured by the presence of a plateau on the tracings of airway opening and oesophageal pressure (Pes). C w was measured directly from the inspired volume of the occluded breath and changes in Pes generated by the recoil of the relaxed chest wall. This airway-occlusion technique yielded reproducible C w values similar to those measured by classical invasive methods. The ratio of C w to bodyweight in the growing calves (sC w ) ranged from 2·2 to 11·5 ml cmH 2 O −1 kg −1 and was correlated negatively with age: (log sC w = 0·91−0·003 x age, r = 0·68)m the rate of decline corresponding well to the multispecies allometric growth relationship.

OBJECTIVE To evaluate the effect of neuromuscular blockade on the elastic properties of the lungs, thorax, and total respiratory system in pigs anesthetized to suppress spontaneous breathing. DESIGN Prospective, randomized, experimental study. SETTING A research laboratory at a university medical center. SUBJECTS Eight healthy, anesthetized pigs, weighing 22 to 25 kg. INTERVENTIONS Pigs, with and without muscular blockade, were mechanically ventilated during an infusion of sodium pentobarbital that was titrated to suppress spontaneous breathing activity. MEASUREMENTS AND MAIN RESULTS No significant differences were observed between pressure/volume curves of the lungs, the chest wall, and the total respiratory system, as determined by inflating and deflating the lungs during anesthesia, with or without neuromuscular blockade, in random order. Functional residual capacity was 985 +/- 87 mL with neuromuscular blockade and 997 +/- 78 mL without neuromuscular blockade (NS). A comparison of the total respiratory system, lung, and chest wall compliances obtained with and without neuromuscular blockade showed high correlations (total respiratory system compliance [r2 = .86]; chest wall compliance [r2 = .83]). CONCLUSION Neuromuscular blockade does not alter the elastic properties of the lungs, chest wall, or total respiratory system in mechanically ventilated pigs receiving sodium pentobarbital anesthesia to suppress spontaneous breathing efforts.

Malnutrition is a disorder of nutrition due either to faulty or inadequate dietary intake, which results in an abnormality in body mass or composition.

It is often difficult to manage optimal ventilation parameter settings in patients with low chest wall compliance, as in an obese patient. This case report demonstrates options to ventilate such difficult patients.