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Results for “Diaphragmatic function”

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At least 199 records · Page 11Linked to original sources

PubMed1977

Topical cardiac hypothermia and phrenic nerve injury.

The relationship between ice-chip cardioplegia and impaired left diaphragmatic function was evaluated in dogs. Direct or indirect contact of the phrenic nerve with crushed ice for 30 or 60 minutes resulted in phrenic paralysis for 6 to 28 days, with responsiveness returning from 7 to 62 days later. Microscopical examination of injured nerves revealed injury to the myelin sheath and preservation of axons. Paralysis of the left diaphragm after topical cardiac hypothermia may be secondary to cold injury of the phrenic nerve, which is reversible.

Animals↗

PubMedDate not supplied

Lung volume reduction surgery: an overview.

Lung volume reduction surgery, originally used in the 1950s, has reemerged as a technique that may help some individuals with end-stage emphysema breathe more easily. The goal of the surgery is to enhance elastic recoil of the lung and to restore diaphragmatic function. The surgery is still in the experimental stages, but early outcome data are encouraging. The purpose of this study was to discuss the pathology of emphysema and the rationale for lung volume reduction. The patient selection criteria for the operation are discussed, and information is provided regarding the preoperative and postoperative management and rehabilitation of these patients by physicians, nurses, respiratory therapists, and physical therapists.

Emphysema↗

PubMed1995

[Artificial nutrition in patients with chronic respiratory insufficiency undergoing surgery].

Denutrition is a common finding in patients with chronic respiratory failure (CRF). Preoperative denutrition increases the risk of nosocomial pneumonia and difficulties in weaning from mechanical ventilation. A preoperative nutritional support may have beneficial effects on respiratory muscles performance. However, prospective studies need to be carried out in patients with CRF to substantiate this hypothesis. Postoperative nutritional support is indicated if weaning from the ventilator is expected to require more than several days, in order to preserve the diaphragmatic function. Lipid-enriched nutrition may have a beneficial effect, when energy supply is high, as the resulting decrease in CO2 production may facilitate the weaning from the ventilator. A beneficial effect of branched-chain amino acid-enriched solutions has not been demonstrated in patients with CRF.

Chronic Disease↗

PubMed1996

Effect of alpha-adrenoreceptor stimulation on the diaphragmatic oxygen delivery-consumption relationship.

PURPOSE: In the vascularly isolated canine hemidiaphragm, we tested the hypothesis that alpha-adrenoreceptor stimulation may influence diaphragmatic function and O2 extraction during reductions in O2 delivery (QO2di). METHODS: The diaphragm was perfused using a constant flow pump with blood diverted from the left femoral artery. QO2di was reduced in a stepwise fashion by progressive reductions in pump flow. The tension generated by the contracting diaphragm (3 Hz), the critical O2 delivery (QO2di,c) below which O2 consumption (VO2di) becomes dependent on O2 supply and the oxygen extraction ratio at this critical point (ERc) were assessed in two groups of animals. Phenylephrine (10(-5) mol/L) was infused into the phrenic artery in one group and saline was infused in another group. RESULTS: In the contracting diaphragm, VO2di was higher in the phenylephrine infused group than in the control group (5.2 +/- 0.5 vs 2.11 +/- 0.3 mL/min/100 g). QO2di,c and ERc were also higher in the phenylephrine group than in the control group (6.16 +/- 0.43 vs 3.1 +/- 0.5 mL/min/100 g and 0.87 +/- 0.035 vs 0.63 +/- 0.05, respectively). In the resting diaphragm, VO2di was not significantly different between the two groups and no critical oxygen delivery could be identified in either group. CONCLUSIONS: These results indicate that alpha-adrenoreceptor activation may increase the tension generated by the diaphragm as well as its oxygen consumption and oxygen extraction. Although this may be beneficial during moderate reductions in oxygen delivery, in more severe shock states, activation of these receptors by endogenous or exogenously administered catecholamines may hasten the development of delivery limitation of VO2di and compromise the ability to sustain ventilation.

Adrenergic alpha-Agonists↗

PubMed1993

Ankylosing spondylitis.

Ankylosing spondylitis is an inflammatory disease involving entheses and joints, especially those in and around the spine. The most widespread involvement of the respiratory system by this disease occurs when this pathological process gives rise to chest wall pain, diminished chest wall movement and a dorsal stoop. As healing of the inflammatory process takes place, calcification occurs which leads to rigidity of these structures, with consequent loss of chest expansion which is exacerbated by the increasingly kyphotic spinal posture and intercostal muscle inefficiency. Fortunately diaphragmatic function is unimpaired and compensates well, so that there are only minor restrictive changes found in tests of respiratory function. Treatment is by mobilizing physiotherapy coupled with a home exercise programme encouraging mobility and improved cardiovascular fitness. As with many physical treatment methods, good quality controlled studies of efficacy are rare. The role of medication is to ease symptoms and hence enable exercise. Apical fibrobullous lung disease is found in a small proportion of AS patients. The initial changes are mainly fibrotic, with bullae becoming more important as the condition progresses. The disease may progress to major cavitation, which is prone to infection, especially with aspergillae. No methods exist which can either prevent the development of fibrobullous disease or halt its progression, although this may happen spontaneously. The main effects of therapy are aimed at the diagnosis and treatment of superinfection. Treatment of established aspergillosis, especially when aspergilloma formation has taken place, is unsatisfactory and carries substantial risks of morbidity and death. Non-apical pleural involvement, including pleural effusion, is very rare. The most common cause of breathlessness in AS patients is cardiac involvement by the disease.

Humans↗

PubMed1999

Surgical aspects and techniques of lung volume reduction surgery for severe emphysema.

Lung volume reduction surgery (LVRS) has become an accepted procedure for palliative treatment of diffuse, nonbullous emphysema. Single or multiple peripheral segmental wedge resections of the most destroyed areas of the lungs are performed with the use of stapling devices, in order to decrease hyperinflation and restore diaphragmatic function. Median sternotomy, videoendoscopy or anterior muscle sparing thoracotomies have been used as surgical approaches. The functional improvement after bilateral resections exceed those after a unilateral approach. LVRS has demonstrated its potential as an alternative to transplantation, and with growing experience, the indications for the procedure have been widened. In selected patients with peripheral lung cancer who have been considered unsuitable for a surgical resection, the combination of both tumour resection and LVRS has successfully been performed. In contrast to LVRS, laser surgery of the emphysematous lung has been abandoned in most institutions.

Contraindications↗

PubMed2000

Hemidiaphragmatic paresis after interscalene supplementation of insufficient axillary block with 3 mL of 2% mepivacaine.

Breathing difficulty, agitation, and confusion developed in a 55-year-old male, ASA classification group III with a non-small-cell lung cancer 10 min after interscalene supplementation of insufficient axillary block with 3 mL of 2% mepivacaine with adrenaline 5 microg mL(-1). After administration of thiopentone and suxamethonium the patient's trachea was intubated and the lungs were ventilated with oxygen-enriched air. The block was successful and surgery was conducted as scheduled. Radiographic monitoring of the lungs at the end of operation showed ipsilateral elevation of the diaphragm with reduced respiratory excursions. Postoperatively, the patient was somnolent and hypercapnic, but maintained satisfactory oxygenation while breathing spontaneously and was extubated. Both the temporal relationship of events and the regression of all symptoms within three hours suggest that 3 mL of mepivacaine with adrenaline injected into the interscalene space blocked the phrenic nerve and compromised diaphragmatic function, which precipitated the respiratory failure.

Anesthetics, Local↗

PubMed1992

Electromyographic registration of diaphragmatic fatigue during sustained trunk flexion in cervical cord injured patients.

When performing forward trunk flexion, cervical cord injured (CCI) patients exhibit continuous and high EMG activity in the diaphragm and elevated abdominal pressures. This study addressed the question whether the trunk flexion manoeuvres cause such a high force development in the diaphragm that this muscle shows EMG signs of fatigue. Six patients with complete cervical cord lesions were tested sitting in their own wheelchairs. The tension-time indices obtained when patients were sitting in a relaxed position were moderately to markedly higher than in normal subjects. The force developed during trunk flexion averaged 30% of the maximal transdiaphragmatic pressure and was accompanied by clear EMG findings of diaphragmatic fatigue in all patients except one. The acute diaphragmatic load in certain CCI patients may well produce ischaemia and increase the risk of tissue impairment. Therefore, there appears to be a need for differing strategies in the short and in the long term treatment of CCI patients; longitudinal evaluation of main diaphragmatic function may be useful for an adequate amount of respiratory muscle training.

Cervical Vertebrae↗

PubMed2000

Effects of pressure support ventilation and continuous positive airway pressure on diaphragm performance.

Many patients who are on mechanical ventilation are on ventilator modes called pressure support ventilation (PSV) and continuous positive airway pressure (CPAP) particularly when they are being weaned. As the diaphragm is responsible for approximately 75% of breathing, it is important to promote diaphragm shortening to optimize weaning from mechanical ventilation. The purpose of our 1998 quasi-experimental study was to explore the effects of PSV and CPVP on diaphragm shortening. An animal model was utilized using four Sprague-Dawley rats from the same litter purchased from Sasco (Kansas City, USA). Also measured in this study were intrathoracic pressure (DeltaITP), positive inspiratory pressure, respiratory rate, tidal volume, end-tidal carbon dioxide, central venous pressure (CVP) and mean arterial pressure (MAP). Pressure support was increased in increments of 5 cm H2O at CPAP levels of 0, 2 and 4 cm H2O. A direct assessment of diaphragm shortening was achieved through the adherence of a miniaturized ultrasonic sensor to the inferior surface of the middle costal surface of the right hemidiaphragm of four Sprague-Dawley rats. Limitations of this study included a small sample size, anaesthetized rats and abdominal dissection for insertion of the ultrasonic sensor. As PSV was increased, there was a decrease in MAP, CVP, respiratory rate and end-tidal CO2. When increasing levels of CPAP were added to PSV, a decrease in diaphragm shortening was observed. These results support that higher levels CPAP may hinder diaphragmatic function thus prolong mechanical ventilation. The purpose of this pilot study was to explore the effects of PSV and CPAP on diaphragm shortening. Also measured were DeltaITP, positive inspiratory pressure, respiratory rate, tidal volume, end-tidal carbon dioxide, CVP and MAP. Pressure support was increased in increments of 5 cm H2O at CPAP levels of 0, 2 and 4 cm H2O. A direct assessment of diaphragm shortening was achieved through the adherence of a miniaturized ultrasonic sensor to the inferior surface of the middle costal surface of the right hemidiaphragm of four Sprague-Dawley rats. Limitations of this study included a small sample size, anaesthetized rats and abdominal dissection for insertion of the ultrasonic sensor. As PSV was increased, there was a decrease in MAP, CVP, respiratory rate and end-tidal CO2. When increasing levels of CPAP were added to PSV, a decrease in diaphragm shortening was observed.

Animals↗

PubMed1985

Regional ventilation in infancy. Reversal of adult pattern.

There is evidence that in infants with unilateral lung disease, oxygenation improves when the good lung is uppermost--the reverse of the situation in adults. We performed krypton-81m ventilation scanning in 18 infants and very young children (11 days to 27 months old) with and without abnormal chest radiographs. Scanning was performed with the subject supine, in the left decubitus posture (right lung uppermost), and in the right decubitus posture (right lung dependent). Fractional ventilation to the right lung fell when that lung was dependent and rose when it was uppermost (P less than 0.001). This pattern was seen regardless of the appearance of the chest radiograph. The distribution of ventilation away from dependent lung regions represents a reversal of the adult pattern, which may be due to differences between infants and adults in lung mechanics and diaphragmatic function. This study adds further weight to the argument that infants and very young children with unilateral lung disease should be positioned with their normal lung uppermost to optimize gas exchange. It also offers a rational explanation for the observation that infants with unilateral gas trapping can be successfully treated by placing them so that the diseased lung is dependent.

Age Factors↗

PubMed2002

Determinants of hospital length of stay after thoracoabdominal aortic aneurysm repair.

PURPOSE: Extended hospital length of stay (LOS) and consequent high costs are associated with thoracic and thoracoabdominal aortic aneurysm (TAAA) surgery. In this study, we examined factors that may influence LOS after TAAA repair. METHODS: Five hundred forty thoracic and TAAA repairs were performed by one surgeon between 1990 and 1999. The data were analyzed with multiple linear regression with appropriate logarithmic transformation. The predictor variables included patient demographics, disease extent, severity indicators, intraoperative factors, and postoperative complications. RESULTS: The median LOS was 15 days. Postoperative creatinine level of greater than 2.9 was the most important predictor of LOS, followed by spinal cord deficit, age, and pulmonary complication (all statistically significant with P <.05). A second model constrained to preoperative risk factors showed both age and complete diaphragmatic division to be associated with increased LOS. Preservation of the diaphragm led to reduced LOS by an average of 4 days. The adjunct cerebrospinal fluid drainage and distal aortic perfusion was associated with a decrease in LOS, although it did not reach statistical significance. CONCLUSION: Renal failure, spinal cord deficit, and pulmonary complication were the major determinants of LOS in patients for TAAA repair. This study shows that the preservation of diaphragmatic function and the use of the adjunct distal aortic perfusion and cerebrospinal fluid drainage may reduce hospital LOS.

Adult↗

PubMed1999

The effects of dantrolene on the contraction, relaxation, and energetics of the diaphragm muscle.

UNLABELLED: Dantrolene is used in patients with muscle spasticity and is the only known effective treatment for malignant hyperthermia. However, its effects on muscle relaxation and energetics are unknown and may have important consequences in diaphragmatic function. We studied the effects of dantrolene (10(-8) to 10(-4) M) on diaphragm muscle strips (n = 12) in the hamster in vitro (Krebs-Henseleit solution, 29 degrees C, 95% oxygen/5% carbon dioxide) in response to tetanic stimulation (50 Hz). We studied contraction and relaxation under isotonic and isometric conditions, as well as energetics. Data are mean +/- SD. Dantrolene induced a negative inotropic effect in the hamster diaphragm (active force at 10(-4) M: 34% +/- 7% of baseline; P < 0.05) but did not significantly modify the curvature of the force-velocity relationship. Dantrolene did not significantly modify isotonic relaxation. Dantrolene, up to 10(-5) M, did not significantly impair isometric relaxation. In conclusion, dantrolene induced a marked negative inotropic effect on diaphragm muscle without affecting myothermal efficiency and relaxation. IMPLICATIONS: Dantrolene induced a significant and concentration-dependent negative inotropic effect on diaphragm muscle but did not modify isotonic relaxation, which suggests no alteration of the calcium reuptake by the sarcoplasmic reticulum; up to 10(-5) M dantrolene did not alter isometric relaxation, i.e., myofilament calcium sensitivity. Dantrolene did not modify the energetics of diaphragm muscle.

Animals↗

PubMed2001

Diaphragm movement before and after cholecystectomy: a sonographic study.

UNLABELLED: Respiratory disorders after abdominal surgery are commonly explained by changes in diaphragmatic movement that are difficult to demonstrate and quantify. Our aim was thus to quantify these changes using a noninvasive method. We used M-mode sonography for the prospective study to measure diaphragmatic amplitude in 14 patients before and after cholecystectomy. During quiet breathing, the diaphragm inspiratory amplitude (DIA) was significantly decreased after surgery from 1.4 +/- 0.2 cm to 1 +/- 0.1 cm and from 1.6 +/- 0.3 cm to 1.2 +/- 0.3 cm in the Laparoscopic and Open Cholecystectomy groups, respectively. The total time cycle of diaphragmatic motion decreased significantly in the two groups. The DIA also decreased significantly during deep breathing after cholecystectomy from 6.0 +/- 0.8 cm to 3.0 +/- 1.8 cm and from 6.1 +/- 1.3 cm to 3.1 +/- 1.6 cm in the Laparoscopic and Open Cholecystectomy groups, respectively. The six patients who underwent spirometric examination showed, during quiet breathing, a significant decrease in DIA without change in tidal volume, i.e., 0.51 +/- 0.08 L to 0.45 +/- 0.08 L. We found a significant decrease in DIA after cholecystectomy and a significant interindividual correlation between DIA during deep inspiration and inspiratory capacity. Using M-mode sonography techniques, we were able to demonstrate changes in diaphragmatic mobility after laparoscopic or open cholecystectomy. IMPLICATIONS: Cholecystectomy at times results in impaired respiratory and diaphragmatic functions. The techniques currently used to study these repercussions are both laborious and invasive. Our sonographic technique is completely noninvasive and can be used to study diaphragm morphology and movement in real time.

Adult↗

PubMed1983

Bilateral diaphragmatic paralysis.

Ventilatory failure developed insidiously in a patient due to bilateral diaphragmatic paralysis from bilateral phrenic neuropathy. The ventilatory failure progressed to respiratory arrest. We assessed the patient's diaphragmatic function by fluoroscopy, transdiaphragmatic pressure measurements during maximal inspiration, measurement of abdominal paradoxic motion, and electrical conduction measurements of the phrenic nerves. He improved and was discharged. A rocking bed was recommended for sleep after appropriate measurements of various respiratory support apparatuses. A history of supine breathlessness and a clinical observation of paradoxic abdominal wall motion during breathing in the supine position should suggest this possible cause.

Aged↗

PubMed2002

Diaphragmatic dysfunction after pediatric orthotopic liver transplantation.

BACKGROUND: Pediatric orthotopic liver transplantation (OLT) has a low mortality. Some children, however, have an adverse outcome defined as a prolonged ventilatory support requirement and protracted pediatric intensive care unit (PICU) stay. The aim of this study was to determine if that adverse outcome related to the child's condition pre-OLT and/or the development of a pleural effusion or diaphragmatic dysfunction. METHODS: The study included 210 children with a median age at transplantation of 45.5 months (range 0.2-252 months). Fourteen had undergone retransplantation. The duration of ventilatory support (intermittent positive pressure ventilation [IPPV]) and PICU admission and development of a pleural effusion and/or diaphragmatic dysfunction were documented for each child. The patients were divided into three groups according to whether they had acute liver failure (ALF), chronic liver disease at home (CHOM), or chronic liver failure sufficiently ill to be in the hospital awaiting transplantation (CHOSP). RESULTS: The 36 children with ALF were of similar age to the 138 CHOM and 36 CHOSP children but required longer IPPV (P<0.0001) and PICU stay (P<0.0001). Overall, 17 children developed diaphragmatic dysfunction and 138 pleural effusions; affected children required longer IPPV and PICU stay (P<0.01). Regression analysis demonstrated that diaphragmatic dysfunction, but not pleural effusion development, was associated with prolonged ventilation (P<0.01) and protracted PICU stay (P<0.05). Other risk factors were ALF (P<0.01), retransplantation (P<0.01), and young age (P<0.05). CONCLUSION: Diaphragmatic dysfunction adversely influences PICU morbidity after OLT. Early assessment of diaphragmatic function, and if necessary aggressive management, might improve outcome.

Adolescent↗

PubMedDate not supplied

Evaluating diaphragm activity in trauma patients.

The diaphragm is the major respiratory muscle responsible for most of the inspiratory work of breathing. Bedside clinicians often overlook the need to assess the diaphragm or have never focused their attention on understanding the mechanisms behind this muscle. This article updates the trauma nurse on the anatomy and physiology of the diaphragm, reviews current methods for assessing diaphragm activity, and discusses research and diagnostic methods concerning the diaphragm. With heightened awareness of diaphragmatic function, clinicians may be able to improve the respiratory status of the trauma patient by preventing diaphragm fatigue or exhaustion.

Diaphragm↗

PubMed2003

Preoperative pneumoperitoneum used for tissue expansion before abdominal wall reconstruction.

The use of preoperative pneumoperitoneum was described initially for the repair of large ventral hernias. Large volumes of air are injected into the peritoneal cavity, which distends the abdominal wall progressively. This method is usually used to facilitate the reinstatement of the viscera into the abdominal cavity and improves postoperative diaphragmatic function. The authors use this method for preoperative tissue expansion of the abdominal wall before full-thickness resection of the abdominal wall for dermatofibrosarcoma protuberans in a 12-year-old girl. In total, 6.8 L air was injected over 3 weeks without problem. The subsequent laxity of the abdominal wall permitted the primary closure of a 14- x 16-cm resection. The postoperative course was uncomplicated. Preoperative pneumoperitoneum can be used when reconstruction can be delayed. This is so in cases of slow tumor growth and in cases of infectious or posttraumatic full-thickness abdominal defects. The parietal laxity obtained with the pneumoperitoneum not only increases the possibilities of direct closure but also increases the possibilities of pedicled flap reconstructions.

Abdominal Wall↗

PubMed1992

Phrenic neuropathy in association with diabetes.

We report the case of a 51-year-old man who presented with breathlessness on exertion and orthopnoea in association with Type 2 diabetes mellitus. Investigation showed bilateral diaphragmatic paralysis due to phrenic neuropathy. There was no evidence of neuropathy or microvascular disease elsewhere. Phrenic neuropathy may be an important, albeit rare, complication of diabetes and diaphragmatic function should be considered in any patient with unexplained breathlessness and orthopnoea.

Diabetes Mellitus, Type 2↗