Translaryngeal tracheostomy in acute respiratory distress syndrome patients

OBJECTIVE: To prevent gas exchange deterioration during translaryngeal tracheostomy (TLT) in patients with acute respiratory distress syndrome (ARDS) ventilation is maintained through a small diameter endotracheal tube (ETT; 4.0 mm i.d.) advanced beyond the tracheostoma. We report on the feasibility of uninterrupted ventilation delivered through a high-resistance ETT in ARDS patients, and relevant ventilatory adjustments and monitoring. DESIGN AND SETTING: Prospective, observational clinical study in an eight-bed intensive care unit of a university hospital. Patients: Eight consecutive ARDS patients scheduled for tracheostomy. INTERVENTIONS: During TLT volume control ventilation was maintained through the 4.0-mm i.d. ETT. Tidal volume, respiratory rate, and inspiratory to expiratory ratio were kept constant. Fractional inspiratory oxygen was 1. Positive end expiratory pressure (PEEP) set on the ventilator (PEEP(vent)) was reduced to maintain total PEEP (PEEP(tot)) at baseline level according to the measured intrinsic PEEP (auto-PEEP). MEASUREMENTS AND MAIN RESULTS: Data were collected before tracheostomy and while on mechanical ventilation with the 4.0-mm i.d. ETT. Neither PaCO(2) nor PaO(2) changed significantly (54.5+/-10.0 vs. 56.4+/-7.0 and 137+/-69 vs. 140+/-59 mmHg, respectively). Auto-PEEP increased from 0.6+/-1.1 to 9.8+/-6.5 cmH(2)O during ventilation with the 4.0-mm i.d. ETT. By decreasing PEEP(vent) we obtained a stable PEEP(tot) (11.4+/-4.3 vs. 11.8+/-4.3 cmH(2)O), and end-inspiratory occlusion pressure (26.7+/-7.4 vs. 28.0+/-6.6 cmH(2)O). Peak inspiratory pressure rose from 33.8+/-8.1 to 77.8+/-12.7 cmH(2)O. CONCLUSIONS: The high-resistance ETT allows ventilatory assistance during the whole TLT procedure. Assessment of stability in plateau pressure and PEEP(tot) by end-inspiratory and end-expiratory occlusions prevent hyperinflation and possibly barotrauma.     

Airway management in the thrombocytopenic cancer patient with acute respiratory failure.

Prolonged endotracheal intubation has been the preferred approach when ventilatory support is required in thrombocytopenic cancer patients, because of concern for the possible hemorrhagic complications of tracheostomy. During the past 3 years, the authors have treated over 100 patients who developed acute respiratory failure while being treated for myeloproliferative or lymphoproliferative malignancies. This experience has suggested a greater incidence of potentially lethal complications among thrombocytopenic patients with prolonged endotracheal intubation than with early tracheostomy, which is now preferred in the critical care facility of this institution. Tracheostomy using electrocautery and careful technique has been performed without complication in 35 patients whose platelet counts were as low as 5,000-20,000/mm3.     

New approaches in the rehabilitation of the traumatic high level quadriplegic

The use of noninvasive alternatives to tracheostomy for ventilatory support have been described in the patient management of various neuromuscular disorders. The use of these techniques for patients with traumatic high level quadriplegia, however, is hampered by the resort to tracheostomy in the acute hospital setting. Twenty traumatic high level quadriplegic patients on intermittent positive pressure ventilation (IPPV) via tracheostomy with little or no ability for unassisted breathing were converted to noninvasive ventilatory support methods and had their tracheostomy sites closed. Four additional patients were ventilated by noninvasive methods without tracheostomy. These methods included the use of body ventilators and the noninvasive intermittent positive airway pressure alternatives of IPPV via the mouth, nose, or custom acrylic strapless oral-nasal interface (SONI). Overnight end-tidal pCO2 studies and monitoring of oxyhemoglobin saturation (SaO2) were used to adjust ventilator volumes and to document effective ventilation during sleep. No significant complications have resulted from the use of these methods over a period of 45 patient-years. Elimination of the tracheostomy permitted significant free time by glossopharyngeal breathing for four patients, two of whom had no measurable vital capacity. We conclude that noninvasive ventilatory support alternatives can be effective and deserve further study in this patient population.     

Prediction and timing of tracheostomy in patients with infratentorial lesions requiring mechanical ventilatory support

OBJECTIVES: To determine the frequency and predictors of successful extubations and tracheostomy in patients with infratentorial lesions requiring mechanical ventilation and to determine the optimal time for tracheostomy based on probability of successful extubation and in-hospital survival according to the duration of translaryngeal intubation. DESIGN: Retrospective chart review. SETTINGS: A neurocritical care unit at a university hospital. PATIENTS: A total of 69 patients with infratentorial lesions who were mechanically ventilated during their intensive care unit stay. MEASUREMENTS AND MAIN RESULTS: Of the 69 patients who were mechanically ventilated, 23 (33%) were successfully extubated. In logistic regression analysis, both the presence of a Glasgow Coma Scale score >7 at time of intubation (odds ratio, 4.8; 95% confidence interval, 1.2-21.7) and the absence of brainstem deficits (odds ratio, 4.3; 95% confidence interval, 1.3-16.7), were independently associated with successful extubation. After extubation, 11 patients were reintubated; seven were reintubated within the same day because of poor control over secretions, airway spasm, or hypoventilation. Tracheostomy was performed in 23 (33%) patients, of whom 19 were successfully weaned off mechanical ventilatory support over a mean period of 3.7+/-4.0 days after tracheostomy. Patients undergoing tracheostomy had a significantly longer intensive care unit stay (19.1+/-9.0 vs. 8.7+/-6.6 days, p < .01) and total hospital stay (34.8+/-18.7 vs. 20.1+/-9.9 days, p < .01) compared with patients who were successfully extubated. The probability of successful extubation or death before extubation or tracheostomy was 67% on the day of intubation, which decreased to 5.8% after translaryngeal intubation for >8 days. CONCLUSIONS: An aggressive policy toward tracheostomy is justified based on the low frequency of successful extubations and high frequency of extubation failures and tracheostomies in patients with infratentorial lesions. The decision regarding tracheostomy should be made on day 8 of mechanical ventilatory support because of the low probability of subsequent extubation or in-hospital death.     

Expiratory time constant for determinations of plateau pressure,respiratory system compliance,and total resistance

Introduction

We hypothesized the expiratory time constant (Ƭ_E) may be used to provide real time determinations of inspiratory plateau pressure (Pplt), respiratory system compliance (Crs), and total resistance (respiratory system resistance plus series resistance of endotracheal tube) (Rtot) of patients with respiratory failure using various modes of ventilatory support.

Methods

Adults (n = 92) with acute respiratory failure were categorized into four groups depending on the mode of ventilatory support ordered by attending physicians, i.e., volume controlled-continuous mandatory ventilation (VC-CMV), volume controlled-synchronized intermittent mandatory ventilation (VC-SIMV), volume control plus (VC+), and pressure support ventilation (PSV). Positive end expiratory pressure as ordered was combined with all aforementioned modes. Pplt, determined by the traditional end inspiratory pause (EIP) method, was combined in equations to determine Crs and Rtot. Following that, the Ƭ_E method was employed, Ƭ_E was estimated from point-by-point measurements of exhaled tidal volume and flow rate, it was then combined in equations to determine Pplt, Crs, and Rtot. Both methods were compared using regression analysis.

Results

Ƭ_E, ranging from mean values of 0.54 sec to 0.66 sec, was not significantly different among ventilatory modes. The Ƭ_E method was an excellent predictor of Pplt, Crs, and Rtot for various ventilatory modes; r² values for the relationships of Ƭ_E and EIP methods ranged from 0.94 to 0.99 for Pplt, 0.90 to 0.99 for Crs, and 0.88 to 0.94 for Rtot (P <0.001). Bias and precision values were negligible.

Conclusions

We found the Ƭ_E method was just as good as the EIP method for determining Pplt, Crs, and Rtot for various modes of ventilatory support for patients with acute respiratory failure. It is unclear if the Ƭ_E method can be generalized to patients with chronic obstructive lung disease. Ƭ_E is determined during passive deflation of the lungs without the need for changing the ventilatory mode and disrupting a patient''s breathing. The Ƭ_E method obviates the need to apply an EIP, allows for continuous and automatic surveillance of inspiratory Pplt so it can be maintained ≤ 30 cm H₂O for lung protection and patient safety, and permits real time assessments of pulmonary mechanics.     

Effect of the larynx on ventilation and respiratory pattern in anesthetized rabbits

The effects of the larynx on ventilation and pattern of breathing have been investigated in anesthetized, spontaneously breathing rabbits. Breathing was either via a tracheostomy or via a supralaryngeal tube in control condition, after laryngeal denervation and after subsequent bilateral midcervical vagotomy. Laryngeal resistance was measured in all experimental conditions when breathing was through the larynx. In control conditions the presence of the larynx in the breathing circuit, as compared to breathing through the tracheostomy, slightly but significantly lowered inspiratory and expiratory airflows, tidal volume, and minute ventilation and increased tracheal pressure. Inspiratory and expiratory durations were not significantly changed. Expiratory laryngeal resistance was higher than inspiratory. Laryngeal deafferentation did not significantly modify values of the respiratory variables. Subsequent motor denervation of the larynx enhanced the decrease in ventilatory parameters due to adding the larynx to the circuit and lengthened the respiratory cycle. Inspiratory laryngeal resistance increased sevenfold and expiratory resistance threefold. Subsequent midcervical vagotomy induced a further increase in inspiratory and expiratory durations and augmented tidal volume independent of the route of breathing, and also reduced laryngeal resistance previously increased by motor denervation. These results reveal the ventilatory effects of the larynx and show the importance of its patency in the pattern of breathing.     

Analysis of an adult Duchenne muscular dystrophy population

BACKGROUND: Advances in management have led to increasing numbers of patients with Duchenne muscular dystrophy (DMD) reaching adulthood. Older patients with DMD are necessarily severely disabled, and their management presents particular practical issues. AIM: To review the management of a late adolescent and adult DMD population, and to identify areas in which the present service provisions may be inadequate to their needs. DESIGN: Retrospective review. METHODS: We studied 25 patients with DMD referred to an adult neuromuscular clinic over a 7-year period. Clinical details were obtained retrospectively, from case notes or direct observations. RESULTS: There were 24 males and one symptomatic female carrier. Nine patients died during the observation period. There was no significant correlation between age of wheelchair confinement and age of death. Sixteen patients received non-invasive positive pressure support. Twelve attended mainstream schools and 12, residential special schools. All the patients lived at home for some or all of the time, when their main carers were either one or both of the parents. The most striking difficulties were with the provision of practical aids, including appropriate hoists and belts, feeding and toileting aids, and the conversion of accommodation. Patients rarely wished to discuss the later stages of their disease, and death was often more precipitate than expected. Death usually occurred outside hospital and the final cause was often difficult to establish. DISCUSSION: Adult patients with DMD develop progressive impairment, due to respiratory, orthopaedic and general medical factors. However, the particular areas of difficulty in this study often reflected inadequate and poorly directed social and medical support, illustrating the need for improvements in the structure, co-ordination and breadth of rehabilitation services for adult patients with DMD.     

Decreased respiratory rate variability during mechanical ventilation is associated with increased mortality

Objective

Patients on ventilatory support often experience significant changes in respiratory rate. Our aim was to determine the possible association between respiratory rate variability (RRV) and outcomes in these patients.

Design

A longitudinal, prospective, observational study of patients mechanically ventilated for at least 12 h performed in a medical-surgical intensive care unit. Patients were enrolled within 24 h of the initiation of ventilatory support. We measured airway signals continuously for the duration of ventilatory support and calculated expiratory flow frequency spectra at 2.5-min intervals. We assessed RRV using the amplitude ratio of the flow spectrum’s first harmonic to the zero frequency component. Measures of the amplitude ratio were averaged over the total monitored time. Patients with time-averaged amplitude ratios <40 % were classified as high RRV and those ≥40 % as low RRV. All-cause mortality rates were assessed at 28 and 180 days from enrollment with a Cox proportional hazards model adjusted for disease acuity by the simplified acute physiology score II.

Results

We enrolled 178 patients, of whom 47 had high RRV and 131 low RRV. Both groups had similar disease acuity upon enrollment. The 28- and 180-day mortality rates were greater for low RRV patients with hazard ratios of 4.81 (95 % CI 1.85–12.65, p = 0.001) and 2.26 (95 % CI 1.21–4.20, p = 0.01), respectively. Independent predictors of 28-day mortality were low RRV, i.v. vasopressin, and SAPS II.

Conclusions

Decreased RRV during ventilatory support is associated with increased mortality. The mechanisms responsible for this finding remain to be determined.     

Respiratory insufficiency in neuronopathic and neuropathic disorders

Twenty-nine patients with a neuronopathic or neuropathic disorder were referred for assessment of respiratory insufficiency between 1978 and 1994. Diagnoses included spinal muscular atrophy (6), chronic idiopathic demyelinating neuropathy (4), Vialetto-van Laere syndrome (3), hereditary motor and sensory neuropathy (3) and a miscellaneous group (5). We also describe seven patients with Guillain-Barre syndrome (GBS) who required long-term ventilatory support for over 6 months to 7 years after the initial illness. Respiratory insufficiency occurred as a consequence of respiratory muscle weakness, impaired bulbar function and restrictive lung defects. In some groups presentation was with progressive nocturnal hypoventilation culminating in acute respiratory failure. Five patients with GBS or chronic idiopathic demyelinating neuropathy were weaned from ventilatory support up to 18 months after the initial illness. The remaining 24 patients required continuous or nocturnal ventilatory support using intermittent positive-pressure ventilation (13), negative pressure ventilation (4), nasal-mask-delivered intermittent positive-pressure ventilation (4), nasal-mask-delivered continuous positive-pressure ventilation (3), mouthpiece-assisted ventilation by day (2) and rocking bed (1). None have been weaned from support after a period of ventilation ranging from one month to 10 years. Eight patients have subsequently died.      

BiPAP-S/T-D30通气支持系统在呼吸衰竭治疗中的应用

探讨ＢｉＰＡＰ－Ａ／Ｔ－Ｄ３０通过支持系统的临床应用方法及其效果。方法对通气效果及其对呼吸功能的影响，该系统配件方便呼气孔与碟式呼气活瓣在不同支持压力水平对ＣＯ２排出量的影响、通气支持与使用呼吸兴奋剂的关系进行了观察。结果通气后ＰａＣＯ２下降１．０８ｋＰａ（Ｐ〈０．０１），ＰａＯ２升高２．２１ｋＰａ（Ｐ〈０．００１）；频率下降，潮气量、吸气峰值流速和指端血氧饱合度明显增加，平均吸气流速即潮气量与吸     

Evolution of life expectancy of patients with Duchenne muscular dystrophy at AFM Yolaine de Kepper centre between 1981 and 2011

ObjectivesRetrospective study over the last 30 years of life expectancy in patients suffering from Duchenne muscular dystrophy (DMD). Analysis of the role of ventilatory assistance and causes of death.Patients and methodsOne hundred and nineteen adult DMD patients were hosted during 1981 to 2011 at AFM Yolaine de Kepper centre, Saint-Georges-sur-Loire, France. Patients’ life expectancy was calculated using Kaplan-Meier model.ResultsLife expectancy without or with ventilatory assistance was 22.16 and 36.23 years, respectively. Similarly, life expectancy of patients born from 1970 (mostly with ventilatory assistance) was 40.95 years old from 1970 and 25.77 years old before 1970. Causes of death changed. Cardiac origins of death have increased from 8% to 44%.ConclusionVentilator assistance, in this study mostly through tracheotomy prolongs by more than 15 years life expectancy of DMD patients. It allows conservation of a satisfactory quality of life, and should be systematically proposed to patients.     

Rescue From Respiratory Dysfunction by Transduction of Full-length Dystrophin to Diaphragm via the Peritoneal Cavity in Utrophin/Dystrophin Double Knockout Mice

Duchenne muscular dystrophy (DMD) is an inherited severe muscle wasting disorder with, thus far, no effective therapy. DMD causes respiratory and cardiac failure as well as muscle wastage. Among the various symptoms, respiratory insufficiency is a major cause of death in DMD patients at about 20 years of age. So, naturally, the improvement of respiratory function will extend the patient''s life. We report here, for the first time, a sensitive procedure using whole-body plethysmography to monitor respiratory parameters detected in the utrophin/dystrophin double knockout mouse (dko mouse), showing quite similar systemic symptoms to human DMD including restrictive ventilatory impairment. Furthermore, we show that a highly efficient dystrophin-transduction to the dko''s diaphragm—achieved by simple intraperitoneal injection of a helper-dependent adenovirus vector (HDAdv) containing the full-length dystrophin expression cassette—provided beneficial results. In spite of dystrophin expression only in the diaphragm, this focal gene transfer could result in the rescue from ventilatory impairment (increased tidal volume (TV) and improvement of compensatory hyperpnea). Our result suggests that a DMD patient''s mortal ventilatory impairment may be improved via technically easy means through the intraperitoneal injection of HDAdv.     

Tracheostomy in critically ill patients

Tracheostomy is a common critical care procedure in patients with acute respiratory failure who require prolonged mechanical ventilatory support. Tracheostomy usually is considered if weaning from mechanical ventilation has been unsuccessful for 14 to 21 days. A recent clinical trial suggested that early tracheostomy may benefit patients who are not improving and who are expected to require prolonged respiratory support. In this study, early tracheostomy improved survival and shortened duration of mechanical ventilation. Minimally invasive bedside percutaneous tracheostomy was introduced recently as an alternative to the traditional surgical technique. In expert hands, the 2 techniques are equivalent in complications and safety; however, the bedside percutaneous approach may be more cost-effective. Tracheostomy should be considered early (within the first week of mechanical ventilation) in patients with a high likelihood of prolonged mechanical ventilation. Depending on local medical expertise and costs, either the percutaneous or the surgical technique may be used.     

Variations in rates of tracheostomy in the critically ill trauma patient

OBJECTIVE: The utility of tracheostomy to expedite weaning and prevent complications in patients with acute respiratory failure is actively debated, with many physicians holding strong opinions regarding the value and timing of this intervention. We postulated that these opinions would be reflected in significant variation in tracheostomy rates across centers. Thus, we set out explore the extent and potential sources of this variation among injured patients cared for in trauma centers in the United States. DESIGN: This is a retrospective cohort study. We used stratification and hierarchical multivariate analysis to evaluate the effect of patient and institutional characteristics on tracheostomy rates and variance decomposition to determine the proportion of variance across institutions explained by patient characteristics. SETTING: Intensive care units within trauma centers participating in the National Trauma Databank. PATIENTS: Injured patients admitted over the years 2001-2003, age >/=16 yrs, with an Injury Severity Score >/=9 and a diagnosis of acute respiratory failure, excluding patients with burn injuries and those with a severe injury to the face or neck who might require tracheostomy for maintenance of an airway. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: There were 17,523 patients meeting inclusion criteria: 4,146 (24%) underwent tracheostomy. The mean tracheostomy rate across centers was 19.6 per 100 hospital admissions with a range of 0-59. This variation persisted after stratification by age, injury mechanism, and severity. Although several patient and injury characteristics were predictive of tracheostomy, there were no identifiable institutional characteristics associated with tracheostomy. Patient characteristics accounted for only 14% of the variance across centers. CONCLUSIONS: There is significant unexplained variation in the rates of tracheostomy in critically injured patients with acute respiratory failure. This variation might reflect preconceived notions of efficacy among physicians practicing in the absence of evidence to guide care. The variation provides evidence of equipoise and emphasizes the need for a well-conducted randomized controlled trial to evaluate the utility of this procedure.     

Efficacy of pulmonary rehabilitation using cervical range of motion exercise in stroke patients with tracheostomy tubes

[Purpose] In this study, stroke patients who were intubated with tracheostomy tubes performed cervical range of motion exercises, and changes in their pulmonary and coughing functions were examined. [Subjects and Methods] Twelve stroke patients who were intubated with tracheostomy tubes participated in the study. The subjects were randomly assigned to either the control group (n=6), which did not perform cervical range of motion exercises, or the experimental group (n=6), which did perform exercises. [Results] With regards to forced vital capacity, forced expiratory volume at one second, and peak cough flow rate before and after the exercises, the control group did not show any significant differences while the experimental group showed statistically significant increases in all three parameters. [Conclusion] The results indicate that cervical range of motion exercises can effectively improve the pulmonary function and coughing ability of stroke patients intubated with tracheostomy tubes, and that cervical range of motion exercises can help in the removal of tracheostomy tubes.Key words: Pulmonary rehabilitation, Stroke, Cervical range of motion exercise     

Clinical predictors and outcomes for patients requiring tracheostomy in the intensive care unit.

OBJECTIVE: To identify clinical predictors for tracheostomy among patients requiring mechanical ventilation in the intensive care unit (ICU) setting and to describe the outcomes of patients receiving a tracheostomy. DESIGN: Prospective cohort study. SETTING: Intensive care units of Barnes-Jewish Hospital, an urban teaching hospital. PATIENTS: 521 patients requiring mechanical ventilation in an ICU for >12 hours. INTERVENTIONS: Prospective patient surveillance and data collection. MEASUREMENTS AND MAIN RESULTS: The main variables studied were hospital mortality, duration of mechanical ventilation, length of stay in the ICU and the hospital, and acquired organ-system derangements. Fifty-one (9.8%) patients received a tracheostomy. The hospital mortality of patients with a tracheostomy was statistically less than the hospital mortality of patients not receiving a tracheostomy (13.7% vs. 26.4%; p = .048), despite having a similar severity of illness at the time of admission to the ICU (Acute Physiology and Chronic Health Evaluation [APACHE] II scores, 19.2 +/- 6.1 vs. 17.8 +/- 7.2; p = .173). Patients receiving a tracheostomy had significantly longer durations of mechanical ventilation (19.5 +/- 15.7 days vs. 4.1 +/- 5.3 days; p < .001) and hospitalization (30.9 +/- 18.1 days vs. 12.8 +/- 10.1 days; p < .001) compared with patients not receiving a tracheostomy. Similarly, the average duration of intensive care was significantly longer among the hospital nonsurvivors receiving a tracheostomy (n = 7) compared with the hospital nonsurvivors without a tracheostomy (n = 124; 30.9 +/- 16.3 days vs. 7.9 +/- 7.3 days; p < .001). Multiple logistic regression analysis demonstrated that the development of nosocomial pneumonia (adjusted odds ratio [AOR], 4.72; 95% confidence interval [CI], 3.24-6.87; p < .001), the administration of aerosol treatments (AOR, 3.00; 95% CI, 2.184.13; p < .001), having a witnessed aspiration event (AOR, 3.79; 95% CI, 2.30-6.24; p = .008), and requiring reintubation (AOR, 2.21; 95% CI, 1.54-3.18; p = .028) were variables independently associated with patients undergoing tracheostomy and receiving prolonged ventilatory support. Among the 44 survivors receiving a tracheostomy in the ICU, 38 (86.4%) were alive 30 days after hospital discharge and 31 (70.5%) were living at home. CONCLUSIONS: Despite having longer lengths of stay in the ICU and hospital, patients with respiratory failure who received a tracheostomy had favorable outcomes compared with patients who did not receive a tracheostomy. These data suggest that physicians are capable of selecting critically ill patients who most likely will benefit from placement of a tracheostomy. Additionally, specific clinical variables were identified as risk factors for prolonged ventilatory assistance and the need for tracheostomy.     

Tracheostomy timing and the duration of weaning in patients with acute respiratory failure

Introduction

The effect of various airway management strategies, such as the timing of tracheostomy, on liberation from mechanical ventilation (MV) is uncertain. We tested the hypothesis that tracheostomy, when performed prior to active weaning, does not influence the duration of weaning or of MV in comparison with a more selective use of tracheostomy.

Patients and methods

In this observational prospective cohort study, surgical patients requiring ≥ 72 hours of MV were followed prospectively. Patients undergoing tracheostomy prior to any active weaning attempts (early tracheostomy [ET]) were compared with patients in whom initial weaning attempts were made with the endotracheal tube in place (selective tracheostomy [ST]).

Results

We compared the duration of weaning, the total duration of MV and the frequency of fatigue and pneumonia. Seventy-four patients met inclusion criteria. Twenty-one patients in the ET group were compared with 53 patients in the ST group (47% of whom ultimately underwent tracheostomy). The median duration of weaning was shorter (3 days versus 6 days, P = 0.05) in patients in the ET group than in the ST group, but the duration of MV was not (median [interquartile range], 11 days [9–26 days] in the ET group versus 13 days [8–21 days] in the ST group). The frequencies of fatigue and pneumonia were lower in the ET group patients.

Discussion

Determining the ideal timing of tracheostomy in critically ill patients has been difficult and often subjective. To standardize this process, it is important to identify objective criteria to identify patients most likely to benefit from the procedure. Our data suggest that in surgical patients with resolving respiratory failure, a patient who meets typical criteria for a trial of spontaneous breathing but is not successfully extubated within 24 hours may benefit from a tracheostomy. Our data provide a framework for the conduct of a clinical trial in which tracheostomy timing can be assessed for its impact on the duration of weaning.

Conclusion

Tracheostomy prior to active weaning may hasten liberation from ventilation and reduce complications. However, this does not reduce the overall duration of MV.

     

Use of the rocking bed in the treatment of neurogenic respiratory insufficiency

We describe 53 patients who received ventilatory support witha rocking bed. Diagnoses included previous poliomyelitis (30),muscular dystrophy (12), motor neurone disease (4), adult-onsetacid maltose deficiency (4) and a miscellaneous group (3). Patientspresented with respiratory insufficiency characterized by diaphragmweakness, progressive nocturnal hypoventilation and/or acuteor chronic respiratory failure. Domiciliary rocking beds wereused by 43 patients for a mean of 16.0 years (range 1 monthto 35 years). Most patients were able to breathe adequatelyby day when sitting or standing, but needed assistance by rockingbed for 6–11 h when lying down for sleep. The rockingbed was well-tolerated, and associated with both symptomaticrelief and amelioration of arterial blood gas abnormalities.Seventeen of these 43 patients discontinued its use, eitherbecause of discomfort (9) or increasing respiratory insufficiency(8). The rocking bed is a valuable adjunct in the managementof the respiratory insufficiency associated with neuro-musculardisease.     

mdx小鼠骨骼肌组织成肌、成脂、成骨基因的特异性表达

背景:干细胞移植是治疗肌营养不良症的有效方法之一,但移植的干细胞在病理骨骼肌中成肌表达较低。目的:通过比较mdx小鼠和C57小鼠的骨骼肌形态及成肌、成脂、成骨基因表达的差异,探讨mdx小鼠骨骼肌病理改变的可能机制。方法:取mdx小鼠与C57小鼠的骨骼肌组织行冰冻切片,苏木精-伊红染色和Vonkossa染色观察两种小鼠肌肉组织的形态特征;提取mdx小鼠和C57小鼠骨骼肌组织总RNA,real-timePCR检测成肌、成脂、成骨相关基因的表达。结果与结论:mdx小鼠骨骼肌有肌纤维坏死和再生,伴有轻度脂肪、纤维结缔组织增生,Vonkossa染色可见钙结节沉积,而C57小鼠的骨骼肌细胞形态清晰,核位于细胞周边。与C57小鼠比较,mdx小鼠肌肉组织成骨、成脂基因表达有不同程度的上调(P<0.05),而成肌基因表达下调(P<0.05)。dystrophin基因缺失及成肌基因表达下调、成骨和成脂基因上调是造成mdx小鼠肌肉组织变性坏死的原因。