Effect of position on the mechanical interaction between the rib cage and abdomen in preterm infants

To determine the influence of body position on chest wall and pulmonary function, we studied the ventilatory, pulmonary mechanics, and thoracoabdominal motion profiles in 20 preterm infants recovering from respiratory disease who were positioned in both the supine and prone position. Thoracoabdominal motion was assessed from measurements of relative rib cage and abdominal movement and the calculated phase angle (an index of thoracoabdominal synchrony) of the rib and abdomen Lissajous figures. The ventilatory and pulmonary function profiles were assessed from simultaneous measurements of transpulmonary pressure, airflow, and tidal volume. The infants were studied in quiet sleep, and the order of positioning was randomized across patients. The results demonstrated no significant difference in ventilatory and pulmonary function measurements as a function of position. In contrast, there was a significant reduction (-49%) in the phase angle of the Lissajous figures and an increase (+66%) in rib cage motion in prone compared with the supine position. In addition, the degree of improvement in phase angle in the prone position was correlated to the severity of asynchrony in the supine position. We speculate that the improvement in thoracoabdominal synchrony in the prone position is related to alterations of chest wall mechanics and respiratory muscle tone mediated by a posturally related shift in the area of apposition of the diaphragm to the anterior inner rib cage wall and increase in passive tension of the muscles of the rib cage. This study suggests that the mechanical advantage associated with prone positioning may confer a useful alternative breathing pattern to the preterm infant in whom elevated respiratory work loads and respiratory musculoskeletal immaturity may predispose to respiratory failure.

Download Full-text

The influence of supine posture on chest wall volume changes is higher in obese than in normal weight children

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2014-0201 ◽

2015 ◽

Vol 40 (2) ◽

pp. 178-183

Author(s):

Letícia Silva ◽

Jacqueline de Melo Barcelar ◽

Catarina Souza Rattes ◽

Larissa Bouwman Sayão ◽

Cyda Albuquerque Reinaux ◽

...

Keyword(s):

Pulmonary Function ◽

Tidal Volume ◽

Chest Wall ◽

Supine Position ◽

Normal Weight ◽

Obese Children ◽

Rib Cage ◽

Percentage Contribution ◽

Supine Posture ◽

And Control

The objective of this study was to analyze thoraco-abdominal kinematics in obese children in seated and supine positions during spontaneous quiet breathing. An observational study of pulmonary function and chest wall volume assessed by optoelectronic plethysmography was conducted on 35 children aged 8–12 years that were divided into 2 groups according to weight/height ratio percentiles: there were 18 obese children with percentiles greater than 95 and 17 normal weight children with percentiles of 5–85. Pulmonary function (forced expiratory volume in 1 s (FEV1); forced vital capacity (FVC); and FEV1/FVC ratio), ventilatory pattern, total and compartment chest wall volume variations, and thoraco-abdominal asynchronies were evaluated. Tidal volume was greater in seated position. Pulmonary and abdominal rib cage tidal volume and their percentage contribution to tidal volume were smaller in supine position in both obese and control children, while abdominal tidal volume and its percentage contribution was greater in the supine position only in obese children and not in controls. No statistically significant differences were found between obese and control children and between supine and seated positions regarding thoraco-abdominal asynchronies. We conclude that in obese children thoraco-abdominal kinematics is influenced by supine posture, with an increase of the abdominal and a decreased rib cage contribution to ventilation, suggesting that in this posture areas of hypoventilation can occur in the lung.

Download Full-text

Influence of submaximal isometric contractions of the hamstrings on electromyography activity and force while functioning as hip extensors

Isokinetics and Exercise Science ◽

10.3233/ies-204172 ◽

2020 ◽

pp. 1-8

Author(s):

Dasom Oh ◽

Wootaek Lim

Keyword(s):

Prone Position ◽

Supine Position ◽

Isometric Contraction ◽

Muscle Length ◽

Biceps Femoris ◽

Emg Activity ◽

Isometric Contractions ◽

Significant Difference ◽

Extension Force ◽

Long Head

BACKGROUND: Although the medial and lateral hamstrings are clearly distinct anatomically and have different functions in the transverse plane, they are often considered as one muscle during rehabilitation. OBJECTIVE: The purpose of the study was to compare the electromyographic (EMG) activity between the prone position and the supine position during maximal isometric contraction and to additionally confirm the effect of submaximal isometric contractions on EMG activity of medial and lateral hamstrings, and force. METHODS: In the prone position, EMG activities of the long head of biceps femoris (BFLH) and semitendinosus (ST) were measured during the maximal isometric contraction. In the supine position, hip extension force with EMG activity were measured during the maximal and the submaximal isometric contractions. RESULTS: EMG activity in the prone position was significantly decreased in the supine position. In the supine position, there was a significant difference between the BFLH and ST during the maximal isometric contraction, but not during the submaximal isometric contractions. CONCLUSIONS: The dependence on the hamstrings could be relatively lower during hip extensions. When the medial and lateral hamstrings are considered separately, the lateral hamstrings may show a more active response, with increased muscle length, in clinical practice.

Download Full-text

PNEUMOTHORAX AND POSTURE

Journal of Experimental Medicine ◽

10.1084/jem.11.3.444 ◽

1909 ◽

Vol 11 (3) ◽

pp. 444-452 ◽

Cited By ~ 1

Author(s):

Charles A. Elsberg

Keyword(s):

Chest Wall ◽

Prone Position ◽

Supine Position ◽

Anterior Chest Wall ◽

Anterior Wall ◽

Open Side ◽

Sound Side ◽

Posterior Mediastinal ◽

Respiratory Movements ◽

Anterior Septum

The last mentioned fact may perhaps find its explanation in the following statements: the two pleural cavities are separated by the layers of the anterior and posterior mediastinal septa. Between the two lies the heart. In the dog, the posterior seems to be somewhat tougher than the anterior septum, and somewhat more fixed and tense. With violent respiratory movements, it is the anterior septum which more especially flaps to and fro and bulges when an opening in the pleura has been made, and it is the anterior septum which is so apt to rupture and thus cause double pneumothorax and the death of the animal. When the dog is on its back, the heart falls backward and the bulging of the anterior mediastinal septum is made more easy. It is different when the animal is on its belly. The heart falls toward the anterior chest wall and thus supports the anterior septum: hence the flapping of the septum, the interference with the respiration of the lung on the sound side, the bulging on expiration on the open side, can not so readily occur. The danger of the open pneumothorax is greatly lessened when the animal is in the prone position. In the supine position the danger of the pneumothorax is due to the falling back of the heart and thus facilitating the rupture of the fragile anterior mediastinal septum; the danger is therefore obviated by fixing the pericardium to the anterior wall of the thorax.

Download Full-text

Post-Cholecystectomy Pulmonary Function following Interpleural Bupivacaine and Intramuscular Pethidine

Anaesthesia and Intensive Care ◽

10.1177/0310057x8901700407 ◽

1989 ◽

Vol 17 (4) ◽

pp. 440-443 ◽

Cited By ~ 16

Author(s):

D. C. Oxorn ◽

G. S. Whatley

Keyword(s):

Postoperative Pain ◽

Pulmonary Function ◽

Postoperative Analgesia ◽

The Other ◽

Pulmonary Mechanics ◽

Postoperative Pulmonary Function ◽

Pain Scores ◽

Significant Difference ◽

Group A ◽

To Receive

Twenty-four patients who were to undergo cholecystectomy were randomised into two groups, one to receive postoperative analgesia with interpleural bupivacaine, 20 ml of a 0.5% solution with adrenaline 5 μg/ml, and the other to receive intramuscular pethidine, 1 mg/kg. Preoperative and postoperative pulmonary function, postoperative pain scores, and days from operation to hospital discharge were recorded and statistically compared. There was no significant difference in pain scores, nor in days to discharge; however, postoperative pulmonary mechanics were significantly poorer in the interpleural group. A hypothesis to explain the differences is offered.

Download Full-text

Prone Versus Supine Position in Intubated COVID-19 Patients With ARDS: A Systematic Review and Meta-Analysis

10.21203/rs.3.rs-820756/v1 ◽

2021 ◽

Author(s):

Dita Aditianingsih ◽

Adhrie Sugiarto ◽

Sidharta Kusuma Manggala ◽

Hansen Angkasa ◽

Ahmad Pasha Natanegara

Keyword(s):

Mechanical Ventilation ◽

Mortality Rate ◽

Partial Pressure ◽

Prone Position ◽

Supine Position ◽

Meta Analysis ◽

Arterial Oxygen ◽

Icu Discharge ◽

Significant Difference ◽

Position Group

Abstract BackgroundThis review determined the effect of prone positioning in changes of partial pressure of arterial oxygen/fraction of inspired oxygen (PaO2/FiO2) ratio, partial pressure of carbon dioxide (PaCO2), mortality rate, ICU length of stay and duration of mechanical ventilation in intubated COVID-19 patients with severe ARDS.MethodsA computer-aided comprehensive electronic bibliographic search from MEDLINE, EMBASE, and Science Direct were conducted. The search comprised the articles written in English and intubated adults (≥ 18 years old) patients with COVID-19. The primary outcome was comparing PaO2/FiO2 ratio between prone and supine position group. Secondary outcomes were PaCO2, ICU discharge, and mortality rate. Review Manager version 5.4 (The Cochrane Collaboration) was used for statistical analyses of the included studies.ResultsA total of 7 articles were determined to be eligible, consisting of 1403 intubated COVID-19 patients with ARDS that showed prone position was associated with a higher PaO2/FiO2 ratio compared to supine position (MD 60.17, 95% CI 46.86 - 73.47; p < 0.00001). Four studies reported the PaCO2 measurement and showed no significant difference between prone and supine position (MD 2.07, 95% CI -2.79 - 6.92; p <0.40). Only two studies reported mortalities, one study had 262 deaths out of 648 patients (40.4%) and one study lost 11 out of 20 patients (55%). One study reported median ICU stay and mechanical ventilation duration (16 days) were significantly longer in prone position group.ConclusionThis meta-analysis showed that prone position improved PaO2/FiO2 ratio in intubated COVID-19 patients with ARDS.

Download Full-text

Effects of Desflurane Versus Propofol Anesthesia on Regional Cerebral Oxygenation during Spinal Surgery in the Prone Position

Anesthesia and Clinical Research ◽

10.31487/j.acr.2021.01.02 ◽

2021 ◽

pp. 1-6

Author(s):

Stachtari Chrysoula ◽

Koraki Eleni ◽

Stachtari Chrysoula ◽

Bagntasarian Stella ◽

Gkiouliava Anna ◽

...

Keyword(s):

Prone Position ◽

Supine Position ◽

Spinal Surgery ◽

Cerebral Oxygenation ◽

Demographic Data ◽

Prone Positioning ◽

Anaesthetic Agents ◽

Oxygen Administration ◽

Hemodynamic Variables ◽

Significant Difference

Context: Postural change during anaesthesia has a complex effect on systemic and cerebral circulations. Aim: The goal of the study was to evaluate the effects of desflurane and propofol on cerebral oxygenation during spinal surgery in the prone position. Settings and Design: A prospective randomized double-blinded trial. Methods and Materials: Fifty-two patients scheduled for spinal surgery were randomly allocated to propofol (n=25) and desflurane (n=27) groups. Anaesthetic agents were maintained to obtain a bispectral index of 50-55. SAP, DAP, HR, SPO2, ETCO2 and right and left rSO2 were assessed at seven-time points: supine position without oxygen administration (T1), supine position with oxygen administration (T2-baseline), intubation in the supine position (T3), just after prone positioning (T4), 10 minutes after prone positioning (T5), at the end of surgery in the prone position (T6) and at the end of anaesthesia in the supine position (T7). PCO2, PO2 and Hb partial were also recorded at T3 and T7. Results: Demographic data, pre-oxygenation hemodynamic variables and rSO2 were comparable between the groups. There was no significant difference between groups in SAP, DAP, HR, SPO2, and ETCO2 (p=0.095, p=0.061, p=0.357, p=0.088, p=0.328 respectively). PCO2, PO2 and Hb were not significant different between groups (p=0.542, p=0.394, p=0.768 respectively). rSO2 values were not significantly different between groups. In the propofol group, right rSO2 was significantly higher at T3 (p=0.017) and significantly lower at T5 (p=0,019) and at T6 (p=0,028) compared to baseline. Left rSO2 decreased significantly from baseline at T5 (p=0.026) in the propofol group. Left and right rSO2 in the desflurane group decreased significantly from baseline at T5 (p=0.0004 and p=0.0115). Conclusion: In the prone position, desflurane and propofol were associated with a significant decrease in rSO2 without differences between these anaesthetics.

Download Full-text

How to improve the safety of bicortical pedicle screw insertion in the thoracolumbar vertebrae: Analysis base on three-dimensional CT reconstruction of patients in the prone position

10.21203/rs.2.19695/v2 ◽

2020 ◽

Author(s):

Chao Xu ◽

Qingxian Hou ◽

Yanchen Chu ◽

Xiuling Huang ◽

Wenjiu Yang ◽

...

Keyword(s):

Pedicle Screw ◽

Prone Position ◽

Vertebral Body ◽

Supine Position ◽

Three Dimensional ◽

Vena Cava ◽

Ct Reconstruction ◽

Screw Insertion ◽

Pedicle Screw Insertion ◽

Significant Difference

Abstract Background: Through the comparison of three-dimensional CT reconstruction between the supine position and the prone position, the relative position of thoracolumbar great vessels and vertebral body was studied, and the shortest safe distance between them was measured to improve the safety of bicortical pedicle screw insertion and reduce the risk of vascular injury. Methods: Forty adults were selected to participate the research. Three-dimensional reconstruction of thoracolumbar (T9-L3) CT was performed in the prone position and the supine position. The relative distance between the Aorta/Inferior Vena Cava (IVC) and vertebral body was obtained as AVD/VVD respectively. The relative angle of the Aorta/ IVC and the vertebral body was calculated as ∠AOY/∠VOY. Self-controlled experiments were carried out in the prone and the supine positions, and the data obtained were analyzed using SPSS 22.0 statistical software. Results: The AVD of the prone position and the supine position was the shortest at T12 (3.18 ±0.68mm), but the difference was not statistically significant. The aorta of the T9-L3 segment was shifted from the anterolateral to the anteromedial. The ∠AOY of the other groups differed significantly between the prone and supine positions in all vertebrae except L1 (P < 0.05), and the aorta in the prone position was more anteromedial than that of supine position. With regard to VVD/∠VOY, there was no significant difference between the prone and supine positions (P≥0.05), and the minimum VVD of L3 segment is greater than 5.4mm. The IVC has no obvious mobility and is fixed in the range of 20 °~ 30 ° near the midline. Conclusion: When using bicortical anchoring of pedicle screws, it is safe to ensure that the protruding tips of the screw is less than 3mm. Due to the mobility of the aorta in different postures and individual differences in anatomy, the prone position CT can help doctors to make better preoperative plans and decisions.

Download Full-text

Comparison between the phase angle and phase shift parameters to assess thoracoabdominal asynchrony in COPD patients

Journal of Applied Physiology ◽

10.1152/japplphysiol.00508.2016 ◽

2017 ◽

Vol 122 (5) ◽

pp. 1106-1113

Author(s):

Desiderio Cano Porras ◽

Adriana C. Lunardi ◽

Cibele C. B. Marques da Silva ◽

Denise M. Paisani ◽

Rafael Stelmach ◽

...

Keyword(s):

Phase Shift ◽

Chest Wall ◽

Phase Angle ◽

Compartment Model ◽

Measurement Tool ◽

Chronic Obstructive ◽

Rib Cage ◽

Copd Patients ◽

Thoracoabdominal Asynchrony ◽

Rest And Exercise

Determining the presence of thoracoabdominal asynchrony in chronic obstructive pulmonary disease (COPD) patients is clinically relevant, but there is no consensus on the optimal parameters for performing this analysis. We assessed 22 COPD patients (FEV1 40 ± 10% predicted) and 13 healthy controls during rest and exercise with optoelectronic plethysmography (70% maximum workload) on a cycle ergometer. Thoracoabdominal asynchrony was calculated by using phase angle and phase shift parameters following a three-compartment model involving the upper and lower rib cages and abdomen. Patients were classified as having thoracoabdominal asynchrony (TAA+) or not (TAA−) based on control values (mean ± 2 SDs). The chest wall volume and compartmental contribution were also measured. Thoracoabdominal asynchrony was observed in the lower rib cage. The phase angle detected more TAA+ patients at rest (15 vs. 7 patients) and during exercise (14 vs. 8 patients) compared with the phase shift. TAA+ patients also presented a lower chest wall volume, lower rib cage contribution, and higher abdominal contribution to chest wall volume compared with the control and TAA− patients. Thoracoabdominal asynchrony was more detectable during rest and exercise using the phase angle parameter, and it was observed in the lower rib cage compartment, reducing the chest wall volume during exercise in patients with COPD. NEW & NOTEWORTHY This study contributes to advance the knowledge over the previous lack of consensus on the assessment of thoracoabdominal asynchrony. We rigorously evaluated the related features that interfere in the measurement of the asynchrony (measurement tool, chest wall model and calculation parameter). Our results suggest that phase angle detects more suitably thoracoabdominal asynchrony that occurs on the lower ribcage and leads to a reduction in the chest wall volume during exercise in COPD patients.

Download Full-text

Emergence from Anesthesia in the Prone versus Supine Position in Patients Undergoing Lumbar Surgery

Anesthesiology ◽

10.1097/00000542-200010000-00014 ◽

2000 ◽

Vol 93 (4) ◽

pp. 959-963 ◽

Cited By ~ 10

Author(s):

Michael A. Olympio ◽

B. Lee Youngblood ◽

Robert L. James

Keyword(s):

Heart Rate ◽

Mean Arterial Pressure ◽

Arterial Pressure ◽

Prone Position ◽

Supine Position ◽

Volatile Anesthetic ◽

Baseline Heart Rate ◽

Lumbar Surgery ◽

Maximum Increase ◽

Significant Difference

Background Conventional supine emergence in patients undergoing prone lumbar surgery frequently results in tachycardia, hypertension, coughing, and loss of monitoring as the patient is rolled supine. The prone position might facilitate a smoother emergence because the patient is not disturbed. No data describe this technique. Methods Fifty patients were anesthetized with fentanyl, nitrous oxide, isoflurane, and rocuronium. By the conclusion of surgery, all patients achieved spontaneous ventilation and full reversal of neuromuscular blockade in the prone position, as the volatile anesthetic level was reduced. Baseline heart rate and mean arterial pressure were recorded. Patients were then randomized at time 0 to the supine (n = 24) or prone (n = 21) position as 100% oxygen was administered. Patients in the supine position were then rolled over, while those in the prone position remained undisturbed. Heart rate, mean arterial pressure, and coughs were recorded until extubation. Tracheas were extubated on eye opening or purposeful behavior. Results When compared with the supine group, prone patients had significantly less increase in heart rate (P = 0.0003, maximum increase 9.3 vs. 25 beats/min), less increase in mean arterial pressure (P = 0.0063, maximum increase 4.8 vs. 19 mmHg), less coughing (P = 0.0004, 7.0 vs. 23 coughs), and fewer monitor disconnections (P < 0.0001). Time to extubation from time 0 was similar (4.0 vs. 3.7 min, prone vs. supine). No one required airway rescue. There was no significant difference in need for restraint (three prone, four supine). Conclusions Prone emergence and extubation is associated with less hemodynamic stimulation, less coughing, and less disruption of monitors, without specifically observed adverse effects, when compared with conventional supine techniques.

Download Full-text

Feasibility, Image Quality and Clinical Evaluation of Contrast-Enhanced Breast MRI Performed in a Supine Position Compared to the Standard Prone Position

Cancers ◽

10.3390/cancers12092364 ◽

2020 ◽

Vol 12 (9) ◽

pp. 2364

Author(s):

Alfonso Fausto ◽

Annarita Fanizzi ◽

Luca Volterrani ◽

Francesco Giuseppe Mazzei ◽

Claudio Calabrese ◽

...

Keyword(s):

Image Quality ◽

Prone Position ◽

Supine Position ◽

Breast Mri ◽

Diagnostic Value ◽

Image Resolution ◽

Classification Systems ◽

Contrast Enhanced ◽

Significant Difference ◽

Magnetic Resonance Imaging Mri

Background: To assess the feasibility, image quality and diagnostic value of contrast-enhanced breast magnetic resonance imaging (MRI) performed in a supine compared to a prone position. Methods: One hundred and fifty-one patients who had undergone a breast MRI in both the standard prone and supine position were evaluated retrospectively. Two 1.5 T MR scanners were used with the same image resolution, sequences and contrast medium in all examinations. The image quality and the number and dimensions of lesions were assessed by two expert radiologists in an independent and randomized fashion. Two different classification systems were used. Histopathology was the standard of reference. Results: Two hundred and forty MRIs from 120 patients were compared. The analysis revealed 134 MRIs with monofocal (U), 68 with multifocal (M) and 38 with multicentric (C) lesions. There was no difference between the image quality and number of lesions in the prone and supine examinations. A significant difference in the lesion extension was observed between the prone and supine position. No significant differences emerged in the classification of the lesions detected in the prone compared to the supine position. Conclusions: It is possible to perform breast MRI in a supine position with the same image quality, resolution and diagnostic value as in a prone position. In the prone position, the lesion dimensions are overestimated with a higher wash-in peak than in the supine position.

Download Full-text