Lung squeezing technique as a volume recruitment manoeuvre in correcting lung atelectasis for preterm infants on mechanical ventilation.

by Ivor Wong (Nga Chung).Thesis (M.Phil.)--Chinese University of Hong Kong, 1998.Includes bibliographical references (leaves 114-120).Abstract also in Chinese.Chapter PART I --- INTRODUCTIONChapter 1. --- CHAPTER 1 BACKGROUND --- p.2Chapter 1.1 --- Objectives --- p.3Chapter 1.2 --- Effects of chest physiotherapy --- p.3Chapter 1.2.1 --- Aims of chest physiotherapy --- p.4Chapter 1.2.1.1 --- Mucus Removal --- p.4Chapter 1.2.1.2 --- Re-expansion of atelectatic lung --- p.9Chapter 1.2.2 --- Chest physiotherapy for neonates --- p.10Chapter 1.2.2.1 --- Pulmonary characteristics in neonates --- p.10Chapter 1.2.3 --- Chest physiotherapy for infants on mcchanical ventilation --- p.12Chapter 1.2.3.1 --- Conventional ventilation --- p.12Chapter 1.2.3.2 --- High frequency ventilation --- p.13Chapter 2. --- CHAPTER 2 NEONATAL CHEST PHYSIOTHERAPY --- p.15Chapter 2.1 --- Traditional physiotherapy means --- p.15Chapter 2.1.1 --- Percussion and Chest vibration --- p.15Chapter 2.1.2 --- Cup percussion (Cupping) --- p.16Chapter 2.1.3 --- Postural drainage (PD) --- p.16Chapter 2.1.4 --- Endotracheal Suctioning --- p.17Chapter 2.1.4.1 --- Adverse effects of endotracheal suctioning --- p.17Chapter 2.2 --- Possible Complications of chest physiotherapy --- p.20Chapter 2.2.1 --- Haemodynamic disturbances --- p.20Chapter 2.2.2 --- Fluctuation of Cerebral Perfusion --- p.21Chapter 2.2.3 --- Cystic brain lesions --- p.22Chapter 2.3 --- Modified manual techniques --- p.23Chapter 2.3.1 --- Theoretical model of lung squeezing technique --- p.23Chapter 2.3.2 --- Lung squeezing technique as a volume recruitment manoeuvre --- p.30Chapter 2.3.2.1 --- Squeezing phase of lung squeezing technique --- p.30Chapter 2.3.2.2 --- Release phase of lung squeezing technique --- p.31Chapter 3. --- CHAPTER 3 PHYSIOTHERAPY PRACTICE IN LOCAL NEONATAL ICU --- p.33Chapter 3.1 --- Current physiotherapy practice in Hong Kong Neonatal ICU settings --- p.33Chapter 3.1.1 --- Endotracheal suctioning protocol in Prince of Wales Hospital --- p.33Chapter 3.1.1.1 --- Suctioning Procedures --- p.34PART II MAIN STUDYChapter 4. --- CHAPTER 4 RESEARCH DESIGN --- p.37Chapter 4.1 --- Ethics --- p.37Chapter 4.2 --- Methods --- p.37Chapter 4.2.1 --- Pilot study --- p.37Chapter 4.2.2 --- Main study --- p.39Chapter 4.2.2.1 --- Hypothesis --- p.39Chapter 4.2.2.2 --- Study Design --- p.39Chapter 4.3 --- Methodology --- p.44Chapter 4.3.1 --- Treatment protocol --- p.44Chapter 4.3.1.1 --- Experimental Group protocol --- p.44Chapter 4.3.1.2 --- Control Group protocol --- p.44Chapter 4.3.2 --- Outcome Measure --- p.45Chapter 4.3.2.1 --- Chest X-ray --- p.45Chapter 4.3.2.2 --- Other Measurements --- p.45Chapter 4.3.3 --- Statistics --- p.48Chapter 5. --- CHAPTER 5 RESULTS --- p.50Chapter 5.2 --- Demographic Data --- p.50Chapter 5.3 --- Resolution of lung atelectasis --- p.56Chapter 5.3.1 --- Distribution of lung atelectasis --- p.56Chapter 5.3.2 --- First re-expansion of lung atelectasis --- p.59Chapter 5.3.3 --- Complete resolution of lung atelectasis --- p.62Chapter 5.3.3.1 --- Sites of rccurrencc of lung atelectasis --- p.65Chapter 5.4 --- Factors correlated with number of treatment sessions required to attain resolution of atelectasis --- p.68Chapter 5.5 --- Ventilator parameters changes --- p.73Chapter 5.6 --- Haemodynamic changes --- p.75Chapter 5.7 --- Arterial blood gas --- p.78Chapter 5.8 --- Other clinical outcome --- p.80Chapter 5.8.1 --- Bronchopulmonary dysplasia --- p.80Chapter 5.8.2 --- Intra-ventricular haemorrhage (IVH) --- p.82Chapter 5.8.3 --- Mortality rate --- p.86Chapter PART III --- EFFECTS OF LUNG SQUEEZING TECHNIQUE ON LUNG MECHANICSChapter 6. --- CHAPTER 6 LUNG MECHANICS STUDY FOR NEONATES --- p.88Chapter 6.1 --- Methods --- p.91Chapter 6.1.1 --- Statistical Analysis --- p.93Chapter 6.2 --- Results --- p.94Chapter PART IV --- DISCUSSION AND CONCLUSIONChapter 7. --- CHAPTER 7 SUMMARY AND CONCLUSION --- p.105Chapter PART V --- REFERENCEChapter 8. --- BIBLIOGRAPHY --- p.114Chapter PART VI --- GLOSSARYChapter PART VII --- APPENDICE

Fluid Flow Simulation and Optimisation with Lattice Boltzmann Methods on High Performance Computers - Application to the Human Respiratory System

An overall strategy for numerical simulations of the full human respiratory system is introduced. The integrative approach takes advantage of numerical simulation, high performance computing and newly developed mathematical optimisation techniques, all based on a mesoscopic model description and on lattice Boltzmann methods as discretisation strategies. Validated numerical results are presented for the simulation of respirations in a real human lung and nose geometry captured by CT

Physiological mechanisms of lung volume reduction coils in emphysema

Emphysema is characterised by airflow limitation that is a result of both loss of elastic recoil and small airways disease. It is poorly responsive to medical therapy. Lung volume reduction coils improve symptoms and lung function in the short term. However their mechanism of action and medium term effectiveness is not fully understood. Methods A randomised controlled study consisting of thirty patients with severe chronic obstructive pulmonary disease was performed. Control patients crossed over to the treatment arm at 12 months. The primary outcome was 6 minute walk distance at 12 months. Changes in spirometry, lung volumes, computed tomography measured lung volumes and gas trapping were also assessed. In a small subgroup of patients detailed physiological characterization was performed to assess changes in airways resistance, ventilation heterogeneity and lung elastic recoil. Results In the randomised study at 12 months, there was no significant difference in 6 minute walk distance between treatment and controls (between group difference 25m, 95% CI -40 to 59, p = 0.7028). There was a trend to improvement in symptoms measured by SGRQ score (-6.53 points, 96% CI -17 to 0.2, p = 0.0589) and significant improvements in FRC (-0.41L, 95% CI -0.86 to -0.1, p = 0.0077). Including the crossovers there were 4 patient deaths (13.3%). Target lobe volume at both inspiration and expiration was reduced with no overall change in gas trapping. Airways resistance by plethysmography did not change significantly. There was no significant change in elastic recoil. Conclusions Treatment with lung volume reduction coils is effective at reducing lung volume and may achieve its effect through volume loss. There could also be an effect through elastic recoil as there was a non-significant trend towards an increase after the intervention. There appears to be no effect on airways resistance. Careful patient selection is required as there is a risk of death following treatment.Open Acces

Physiological system modelling and clinical simulation for diagnosis

Chapter 0 Contains the thesis introduction thesis and concepts of NDIs, derivations and applications. It also summarizes the PNDIs that are derived in the subsequent chapters. Chapter 1 Introduces the concept of using Physiological Non-Dimensional Indexes (PNDI) for distinguishing or classifying patients who were diabetic from non-diabetic and those who are the risk of becoming diabetic. In the authors work, he has also demonstrated that those who were diabetic were actually at-risk and those who were normal were in fact at the rim of becoming diabetic. All the works were verified against with clinical data by parametric identification techniques. Chapter 2 Using the findings of the above chapter, the author conceptualized, and design and simulated a dynamic activity-based insulin infusion system. He has used the clinical data of diabetic patients in the above chapter for demonstrating the operations of the system. He has even demonstrated the stability of the system by having continual simulations till 4-hour. Chapter 3 In this chapter, the author has derived a series of system equations for identification of pulmonary diseases based in the inhale and exhale gas mixtures concentrations and volume space. Chapter 4 In this chapter, the author has derived a series of system equations for identification of diseased lungs based of the lungs’ pressurevolume graphs. He has even demonstrated the techniques of obtaining the Cardiac Output (CO) non-invasively. Chapter 5 The author has demonstrated how to obtain the relative urine outflow non-invasively for normal kidneys. Chapter 6 The author has described the significance and derivation background of PNDI

Identification and Characterisation of tracheal cartilage derived stem cells for airway tissue engineering

The trachea is a complex organ composed of multiple cell types and is just one integral part of the respiratory system and as a result of injury or insult there is an immediate need to engineer a neo-trachea as there currently no long-term treatments for tracheal defects. This thesis has for the first time successfully identified a mesenchymal derived stem/progenitor cell component that reside within the tracheal C-ring cartilage by means of selective adhesion protocol of fibronectin for airway tissue engineering applications. These cells were found to be, plastic adherent, colony forming, expressed the minimal cell surface markers and were capable of undergoing tri-lineage. Further analysis revealed mechanical property changes in that the tracheal colony forming cells became stiffer with each passage and the gene expression of collagen I, II and X were reduced. To investigate the chondrogenic potential of tracheal stem/progenitor cells traditional pellet culture over a 21-day time course resulted in matrix formation consisting of collagen type II, aggrecan, collagen type I and possible calcification. To rule out the influence of plastic culture 3D gelatin- derived microcarrier culture techniques in both static and wave culture technology were employed for large expansion of tracheal chondroprogenitors. Post expansion analysis revealed that lubricin (PRG4) transcription was observed in all wave expanded cells which is indicative of superficial zone of articular cartilage and not tracheal cartilage. Post differentiation analysis of the microcarrier constructs revealed similar gene profiles to that observed in traditional pellet culture, although with a slight reduction in gene expression. However, microcarrier based differentiation reduced collagen type X gene expression when compared to traditional pellet culture in all the microcarrier groups. These findings taken together show great potential in the wider cartilage research community in that microcarrier and bioreactor expansion can induce the transcription of PRG4 which is specific to the superficial zone of articular cartilage. Furthermore, as a proof concept C-ring like structures were fabricated using tracheal cartilage derived stem/progenitor cells and microcarriers in 3D printed moulds for use as a customisable new method for airway tissue engineering

Mechanical Ventilation

Mechanical ventilation, ventilator management, and weaning from mechanical ventilation vary based on location within the hospital, type of lung injury, and medical condition of the patient. Understanding the types of lung injury and various methods of achieving ventilation expand the armamentarium of the practitioner and allow for the best management decisions. This book begins with the use of a high-flow nasal cannula (HFNC) and a detailed description of the advanced modes of ventilation. The information on the types of ventilation can then be applied to the ventilation approaches in different populations of patients: the trauma patients, the obese patients, and the patients under neurocritical care. The conclusion contains a discussion of the mechanisms on how to wean from mechanical ventilation and how certain medical conditions affect the weaning process

Effects Of COPD And Its Treatment On Cardiovascular Structure And Function Assessed Through Advanced Imaging Techniques

PhDSignificant cardiovascular morbidity and mortality exists in chronic obstructive pulmonary disease independent of traditional risk factors. A number of different hypotheses exist to explain this association including the contribution arterial stiffness and lung hyperinflation. Non-invasive cardiovascular imaging and assessment are ideal methods through which this relationship can be further studied although a number of the techniques have yet to be validated in COPD. In this thesis we aimed to achieve a number of goals. First, we aimed to assess the reproducibility and level of agreement between different measures of arterial stiffness in stable hyperinflated COPD. Second, we hoped to establish the utility of 3 different measurement techniques for measuring intrinsic cardiac function in stable hyperinflated COPD. Third, in a case-control study we compared surrogates of cardiovascular risk in hyperinflated COPD patients and a group matched for cardiovascular risk with normal lung function. Finally, we sought to understand the impact of pharmacologically reducing lung hyperinflation on cardiovascular structure, function and arterial stiffness. We have firstly demonstrated that non-invasive measures of arterial stiffness are reproducible in stable hyperinflated COPD. Secondly, we have established the level of agreement and reproducibility of three different CMR techniques for measuring intrinsic myocardial function which will provide important information for the powering of future CMR studies in COPD. Thirdly, we have shown that surrogates for cardiovascular outcomes are adversely affected in COPD compared to a group matched for global cardiovascular risk, suggesting that current scoring systems may be suboptimal in risk prediction in COPD. Finally, we have demonstrated that pharmacological lung deflation has consistent and physiologically plausible beneficial effects on cardiac structure, function and the pulmonary vasculature. Whether intrinsic myocardial function can be modulated through prolonged periods of lung deflation is as yet unverified and should be the focus of future clinical trials.GlaxoSmithKline Bart’s Charity Special Purpose Fund