Noninvasive ventilation (NIV) is the provision of ventilatory support without the need for an invasive airway, and has revolutionized the management of patients with diverse forms of respiratory failure. The advantages of NIV include improved patient comfort and reduced need for sedation, while avoiding the complications of endotracheal intubation, including upper airway trauma, sinusitis, otitis, and nosocomial pneumonia. In selected patients, NIV has also been shown to improve survival. The role of NIV in acute severe asthma is at best controversial. In this case report, we describe a patient with acute severe asthma who was initially managed and failed with NIV, and was successfully managed with invasive ventilation. We also review the pathophysiological mechanisms of benefit of NIV in acute severe asthma, and the current literature on the use of NIV in acute asthma. In conclusion, a trial of NIV in acute asthma may be justified in carefully selected and monitored patients who do not respond to initial medical therapy. However, as its role is not clear and as the condition of an asthmatic patient may deteriorate abruptly, extreme caution is advisable to recognize failure of NIV as in the case presented here. Facilities for immediate endotracheal intubation and next level of treatment should be readily available.
Previous studies have demonstrated that domiciliary ventilatory support improves survival, quality of life and cognitive function in motor neuron disease (MND). These benefits are partly attributed to better sleep quality and less hypoxia. In a retrospective analysis we compared the effect of non-invasive (NPPV, n = 52), tracheostomy (TPPV, n = 23) and no ventilation (n = 43) on sleep and survival in MND patients over a seven-year period. The TPPV and NPPV groups had more sleep arousals (AI, p = 0.024), more respiratory events (p = 0.001) and more time asleep with an oxygen saturation less than 90% (%TST with SpO2<90%, p = 0.01), than those who were not ventilated. After treatment with TPPV or NPPV, the percentage of rapid eye movement sleep increased (p<0.001) and the %TST with Sp02<90% (p = 0.006) and AI (p = 0.001) decreased. Improvements were larger and more consistent with NPPV. The median survival of those who used TPPV was 41 months, NPPV 32 months and of those not ventilated was 25 months, significantly different four years (p = 0.0497) after symptom onset. In this retrospective cohort of MND patients, ventilation, particularly NPPV, markedly improved sleep and conferred a modest survival advantage.
INTRODUCTION: In the absence of syringobulbia, hindbrain hernia does not commonly cause permanent respiratory complications. We present two patients who developed permanent central nocturnal hypoventilation following acute deterioration of hindbrain-hernia-related syringomyelia despite successful surgery. PATIENTS: Two children (one boy and one girl, aged 7 and 13 years, respectively) presented with acute neurological deterioration. The boy presented with a 6-week history of progressive tiredness and weakness and a short history of respiratory depression. The girl presented with a 2-year history of left hemiparesis and a short history of left hemiplegia and respiratory depression. On magnetic resonance scan, both had hindbrain hernia, hydrocephalus and cervical syringomyelia. Following cranio-vertebral decompression and, later, a ventriculoperitoneal shunt, the syringomyelia remained well controlled in both patients. In contrast, their respiratory depression improved minimally. Repeated multichannel respiratory monitoring revealed a persistently slow sleeping respiratory rate, with nocturnal hypercapnia and hypoxemia, managed successfully by night-time non-invasive ventilation. Neither the boy nor the girl, after 7 and 4 years, respectively, has developed any complications of nocturnal hypoventilation. When awake, both breathe normally. RESULT: Both children appear to have suffered a permanent impairment of respiratory control, resulting in nocturnal hypoventilation. This is usually seen with brain stem lesions and is unexpected when syringomyelia does not extend above C2, in the absence of syringobulbia. DISCUSSION: Central nocturnal hypoventilation is postulated to be due to permanent damage of central brain stem pathways controlling the respiratory muscles, due to local pressure at the cranio-cervical junction associated with acute deterioration of the hindbrain herniation. CONCLUSION: Sudden deterioration of hindbrain hernia and cervical syringomyelia can rarely impair the central mechanisms of respiratory control, with long-term implications on quality of life.
BACKGROUND: Few patients with amyotrophic lateral sclerosis currently receive non-invasive ventilation (NIV), reflecting clinical uncertainty about the role of this intervention. We aimed to assess the effect of NIV on quality of life and survival in amyotrophic lateral sclerosis in a randomised controlled trial. METHODS: 92 of 102 eligible patients participated. They were assessed every 2 months and randomly assigned to NIV (n=22) or standard care (n=19) when they developed either orthopnoea with maximum inspiratory pressure less than 60% of that predicted or symptomatic hypercapnia. Primary validated quality-of-life outcome measures were the short form 36 mental component summary (MCS) and the sleep apnoea quality-of-life index symptoms domain (sym). Both time maintained above 75% of baseline (T(i)MCS and T(i)sym) and mean improvement (microMCS and microsym) were measured. FINDINGS: NIV improved T(i)MCS, T(i)sym, microMCS, microsym, and survival in all patients and in the subgroup with better bulbar function (n=20). This subgroup showed improvement in several measures of quality of life and a median survival benefit of 205 days (p=0.006) with maintained quality of life for most of this period. NIV improved some quality-of-life indices in those with poor bulbar function, including microsym (p=0.018), but conferred no survival benefit. INTERPRETATION: In patients with amyotrophic lateral sclerosis without severe bulbar dysfunction, NIV improves survival with maintenance of, and improvement in, quality of life. The survival benefit from NIV in this group is much greater than that from currently available neuroprotective therapy. In patients with severe bulbar impairment, NIV improves sleep-related symptoms, but is unlikely to confer a large survival advantage.
BACKGROUND: In chronic obstructive pulmonary disease (COPD), body mass index (BMI) is an important predictor of survival. Little is known about the prevalence of malnutrition or longitudinal changes of BMI in patients undergoing noninvasive positive-pressure ventilation (NPPV). METHODS: In a cohort study of 141 patients with COPD and severe chronic respiratory failure (mean forced expiratory volume in the first second [FEV(1)] 0.80 +/- 0.27 L, mean P(aCO(2)) 55.6 +/- 8.8 mm Hg), we investigated nutritional status in relation to respiratory impairment. Changes in BMI were evaluated at 6 and 12 months after initiation of NPPV. RESULTS: Malnutrition, indicated by a BMI of < 20 kg/m(2), was found in 20.6% of the patients. BMI was significantly correlated with the severity of respiratory impairment, especially with hyperinflation (residual volume divided by total lung capacity, r = -0.55, p < 0.001). In malnourished patients (BMI < 20 kg/m(2)) there was a significant increase in body weight after 6 months (6.2 +/- 12.5%, p < 0.05) and 12 months (12.8 +/- 16.0%, p < 0.01), whereas there were no significant changes in the overall study population. Furthermore, there was no correlation between changes in BMI and changes in blood-gas values, lung function, or inspiratory muscle function, either in the entire patient group or in the subgroup of malnourished patients. CONCLUSIONS: In COPD with chronic respiratory failure, malnutrition is common and strongly related to hyperinflation. After initiation of NPPV, a significant weight gain is observed in malnourished COPD patients.
Background: Non-invasive positive pressure ventilation (NPPV) is an accepted treatment option for chronic ventilatory failure due to restrictive thoracic disorders. Objective: The impact of ventilation setting and the duration of ventilator use on changes in physiological and functional parameters has not yet been evaluated. Methods: Effects of NPPV on body plethysmographic parameters, blood gas tension and inspiratory muscle function up to 12 months were analyzed in 44 patients with thoracic cage abnormalities in a clinical stable condition. Furthermore, the influence of ventilator parameters and the duration of ventilator use on these changes was determined. Results: A significant improvement in blood gas parameters (PaCO2, PaO2 and base excess; p < 0.001), lung volumes (VC, TLC and FEV1; p < 0.001) and inspiratory muscle function (PImax, P0.1; p < 0.01 and p < 0.05) was found after 3.8 ± 0.8 months of treatment. As shown by a subgroup analysis, changes were already achieved within the first 3 months of NPPV and then remained stable over time. Improvements in VC were positively correlated with IPAP (r = 0.55; p < 0.001). Reduction in PaCO2 was positively correlated with the quotient (IPAP - EPAP)/weight (r = 0.55; p < 0.001). No correlation could be detected between changes in functional parameters and the duration of ventilator use. Conclusions: NPPV can improve blood gas parameters, lung volume and inspiratory muscle function in thoracic restrictive disorders. To best utilize the potential of NPPV treatment, it seems to be more effective to optimize pressure levels than to extend the duration of ventilation.
PURPOSE: To summarize the evidence comparing noninvasive positive pressure ventilation (NPPV) and invasive positive pressure ventilation (IPPV) weaning on mortality, ventilator associated pneumonia and the total duration of mechanical ventilation among invasively ventilated adults with respiratory failure. SOURCE: Meta-analysis of randomized and quasi-randomized studies comparing early extubation with immediate application of NPPV to IPPV weaning. We selected randomized studies that 1) included adults, with respiratory failure, invasively ventilated for at least 24 hr; 2) compared extubation with immediate application of NPPV to weaning using IPPV; and 3) reported at least one clinically important outcome. PRINCIPAL FINDINGS: We searched MEDLINE (1966 to 2003), EMBASE (1980 to 2003) and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 2, 2003) for randomized controlled trials comparing NPPV and IPPV weaning. Additional data sources included personal files, conference proceedings and author contact. Two reviewers independently assessed trial quality and abstracted data. Five studies enrolling 171 patients demonstrated that compared to IPPV, noninvasive weaning decreased mortality (relative risk, 0.41 [95% confidence interval [CI] 0.22-0.76]), ventilator associated pneumonia (relative risk, 0.28 [95% CI 0.09-0.85]) and the total duration of mechanical ventilation (weighted mean difference, -7.33 days [95% CI -11.45 to -3.22 days]). CONCLUSIONS: In the absence of a large randomized controlled trial, this meta-analysis demonstrated a consistent positive effect of noninvasive weaning on mortality. Notwithstanding, the use of NPPV to facilitate weaning, in mechanically ventilated patients, with predominantly chronic obstructive pulmonary disease, is associated with promising, but insufficient, evidence of net clinical benefit at present.
OBJECTIVE: The growing shift toward home care services assumes that "being home is good" and that this is the most desirable option. Although ethical issues in medical decision-making have been examined in numerous contexts, home care decisions for technology-dependent children and the moral dilemmas that this population confronts remain virtually unknown. This study explored the moral dimension of family experience through detailed accounts of life with a child who requires assisted ventilation at home. This study involved an examination of moral phenomena inherent in (1) the individual experiences of the ventilator-assisted child, siblings, and parents and (2) everyday family life as a whole. METHODS: A qualitative method based on Richard Zaner's interpretive framework was selected for this study. The population of interest for this study was the families of children who are supported by a ventilator or a positive-pressure device at home. Twelve families (38 family members) were recruited through the Quebec Program for Home Ventilatory Assistance. Children in the study population fell into 4 diagnostic groups: (1) abnormal ventilatory control (eg, central hypoventilation syndrome), (2) neuromuscular disorders, (3) spina bifida, and (4) craniofacial or airway abnormalities resulting in upper airway obstruction. All 4 of these diagnostic groups were included in this study. Among the 12 children recruited, 4 received ventilation via tracheostomies, and 8 received ventilation with face masks. All of the latter received ventilation only at night, except for 1 child, who received ventilation 24 hours a day. Family moral experiences were investigated using semistructured interviews and fieldwork observations conducted in the families' homes. RESULTS: Data analysis identified 6 principal themes. The themes raised by families whose children received ventilation invasively via a tracheostomy were not systematically different or more distressed than were families of children with face masks. The principal themes were (1) confronting parental responsibility: parental responsibility was described as stressful and sometimes overwhelming. Parents needed to devote extraordinary care and attention to their children's needs. They struggled with the significant emotional strain, physical and psychological dependence of the child, impact on family relationships, living with the daily threat of death, and feeling that there was "no free choice" in the matter: they could not have chosen to let their child die. (2) Seeking normality: all of the families devoted significant efforts toward normalizing their experiences. They created common routines so that their lives could resemble those of "normal" families. These efforts seemed motivated by a fundamental striving for a stable family and home life. This "striving for stability" was sometimes undermined by limitations in family finances, family cohesion, and unpredictability of the child's condition. (3) Conflicting social values: families were offended by the reactions that they faced in their everyday community. They believe that the child's life is devalued, frequently referred to as a life not worth maintaining. They felt like strangers in their own communities, sometimes needing to seclude themselves within their homes. (4) Living in isolation: families reported a deep sense of isolation. In light of the complex medical needs of these children, neither the extended families nor the medical system could support the families' respite needs. (5) What about the voice of the child? The children in this study (patients and siblings) were generally silent when asked to talk about their experience. Some children described their ventilators as good things. They helped them breathe and feel better. Some siblings expressed resentment toward the increased attention that their ventilated sibling was receiving. (6) Questioning the moral order: most families questioned the "moral order" of their lives. They contemplated how "good things" and "bad things" are determined in their world. Parents described their life as a very unfair situation, yet there was nothing that they could do about it. Finally, an overarching phenomenon that best characterizes these families' experiences was identified: daily living with distress and enrichment. Virtually every aspect of the lives of these families was highly complicated and frequently overwhelming. An immediate interpretation of these findings is that families should be fully informed of the demands and hardships that would await them, encouraging parents perhaps to decide otherwise. This would be but a partial reading of the findings, because despite the enormous difficulties described by these families, they also reported deep enrichments and rewarding experiences that they could not imagine living without. Life with a child who requires assisted ventilation at home involves living every day with a complex tension between the distresses and enrichments that arise out of this experience. The conundrum inherent in this situation is that there are no simple means for reconciling this tension. This irreconcilability is particularly stressful for these families. Having their child permanently institutionalized or "disconnected" from ventilation (and life) would eliminate both the distresses and the enrichments. These options are outside the realm of what these families could live with, aside from the 1 family whose child is now permanently hospitalized, at a tremendous cost of guilt to the family. CONCLUSIONS: These findings make important contributions by (1) advancing our understanding of the moral experiences of this group of families; (2) speaking to the larger context of other technology-dependent children who require home care; (3) relating home care experiences to neonatal, critical care, and other hospital services, suggesting that these settings examine their approaches to this population that may impose preventable burdens on the lives of these children and their families; and (4) examining a moral problem with an empirical method. Such problems are typically investigated through conceptual analyses, without directly examining lived experience. These findings advance our thinking about how we ought to care for these children, through a better understanding of what it is like to care for them and the corresponding major distresses and rewarding enrichments. These findings call for an increased sensitization to the needs of this population among staff in critical care, acute, and community settings. Integrated community support services are required to help counter the significant distress endured by these families. Additional research is required to examine the experience of other families who have decided either not to bring home their child who requires ventilation or withdraw ventilation and let the child die.
BACKGROUND: Noninvasive positive pressure ventilation (NPPV) has been used safely and effectively to improve gas exchange and to treat respiratory failure in a variety of disease states. Although this technique has some benefits in the treatment of status asthmaticus in adults, the use of NPPV in pediatric patients with asthma has not been described. OBJECTIVE: To describe the use of NPPV in the treatment of pediatric status asthmaticus. METHODS: Retrospective review of children admitted to the intensive care unit with asthma who received NPPV as part of their treatment between October 2002 and April 2004. Before and after initiation of NPPV, data were collected regarding degree of respiratory dysfunction. RESULTS: Of seventy-nine children admitted to the intensive care unit during the study period for treatment of status asthmaticus, 5 children (mean +/- SD age, 9.6 +/- 4.2 years) were treated with NPPV. Four of the 5 children were morbidly obese, with a mean +/- SD body mass index of 32 +/- 5. There was a statistically significant improvement in respiratory rate (43 +/- 20 vs 31 +/- 12/min, P = .03) and Modified Pulmonary Index Score (13.4 +/- 1.8 vs 11.4 +/- 1.5, P = .03) after initiation of NPPV. The mean +/- SD duration of therapy was 33.2 +/- 23.9 hours, and children tolerated this therapy well, requiring little or no anxiolytics. CONCLUSIONS: NPPV was well tolerated in this series of children with status asthmaticus and can improve subjective and objective measures of respiratory dysfunction. NPPV may be a useful adjunct in the treatment of status asthmaticus in children.
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Downie P
Br J Hosp Med (Lond) 2006; 67:220
Should I wheel out the heliox with non-invasive ventilation?
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We performed a retrospective analysis to the effects of negative pressure ventilation (NPV), tracheal intermittent positive pressure ventilation (TIPPV), and nasal intermittent positive pressure ventilation (NIPPV, volume or pressure-controlled ventilatory mode), in 114 patients with restrictive ventilatory disorders instituted in our hospital from 1956 until 2005. The patients were assigned on "ad hoc" basis to NPV, TIPPV, or NIPPV. All patients were subdivided in an idiopathic kyphoscoliosis group (IK, n=64), a post-poliomyelitis syndrome group (PP, n=30), or a miscellaneous group (M, n=20). The patients in the PP group had higher survival rates compared to the IK patients (P<0.05), while the M patients had the lowest survival rates (P<0.01). Both NPV (P<0.01) and TIPPV (P<0.05) lead to a decrease in PaCO(2) after 9 months compared to baseline. This decrease in PaCO(2) was still present after 5 years NPV (P<0.001) and TIPPV (P<0.05). NIPPV lead to an improvement in pulmonary function (P<0.05) and arterial blood gases (P<0.001) after 9 months compared to baseline. After 5 years NIPPV, the arterial blood gases were still significantly improved compared to baseline (P<0.01). Both volume-controlled and pressure-controlled ventilation improved pulmonary function and arterial blood gases. CONCLUSION: Long-term home mechanical ventilatory support by both NPV and positive pressure ventilation is effective in patients with IK, PP syndrome, and a M group, even after a period of 5 years.
- Duke GJ, Bersten AD
Crit Care Resusc 1999; 1:198
Non invasive ventilation for adult acute respiratory failure. Part I
OBJECTIVE: To detail the history, modes, physiological effects, and circuit geometry of non-invasive ventilation. DATA SOURCES: A review of articles published in peer-reviewed journals from 1966 to 1998 and identified through a MEDLINE search on non-invasive ventilation. SUMMARY OF REVIEW: Non-invasive ventilation (NIV) has been used for many years as an adjunct to standard therapy in patients with acute and chronic respiratory disorders. The newer modes of NIV which include continuous positive airway pressure (CPAP), pressure support ventilation (PSV), BiPAP (bi-level positive airway pressure) and controlled and assisted modes of intermittent non-invasive positive pressure ventilation (NIPPV) have additional advantages and are often used routinely in many respiratory diseases. These modes of ventilatory support have been found to improve arterial oxygenation, ventilation, work of breathing, and cardiac function, in patients with respiratory failure, although in normal subjects, respiration is often impaired.. CONCLUSIONS: Non-invasive ventilation using the modes of CPAP, PSV, BiPAP and NIPPV should be considered in patients with respiratory failure who are unresponsive to conventional therapy, before considering invasive mechanical ventilation.
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Duke GJ, Bersten AD
Crit Care Resusc 1999; 1:210
Non invasive ventilation for adult acute respiratory failure. Part II
OBJECTIVE: To discuss the clinical indications and complications of non-invasive ventilation. DATA SOURCES: A review of articles published in peer-reviewed journals from 1966 to 1998 and identified through a MEDLINE search on non-invasive ventilation. SUMMARY OF REVIEW: Non-invasive ventilation (NIV) has been used in patients with respiratory failure caused by cardiogenic pulmonary oedema, acute respiratory distress syndrome, acute asthma and chronic obstructive pulmonary disease. However, in patients with acute respiratory failure, it appears that acute cardiogenic pulmonary oedema and acute respiratory failure associated with Pneumocystis carinii pneumonia are the only disorders in which significant benefits have been associated with the use of the NIV mode of CPAP. The potential clinical benefit of CPAP in acute asthma and blunt chest trauma remains unclear. Pressure support ventilation is beneficial in patients with hypercapnic acute respiratory failure (ARF) secondary to respiratory muscle insufficiency, high inspiratory work loads, or reduced alveolar ventilation. It appears also to be associated with an improved outcome in COPD patients with hypercapnic ARF. CONCLUSIONS: Non-invasive ventilation using the modes of CPAP, PSV, BiPAP and NIPPV should be considered in patients with respiratory disorders who remain in acute respiratory failure despite conventional therapy, before considering invasive mechanical ventilation.
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Eng D
Palliat Med 2006; 20:69-79
Management guidelines for motor neurone disease patients on non-invasive ventilation at home
Most motor neurone disease (MND) patients die of respiratory system complications. When patients have advanced disease with symptoms of respiratory failure, management issues can become complicated by the introduction of assisted ventilatory devices. Therefore, care provision by a multidisciplinary team must be structured and co-ordinated in order to ensure that patients and their carers receive the optimal level of care. The objective of this article is to review the literature and explore the complex issues surrounding the use of non-invasive positive pressure ventilation (NIPPV) in home care MND patients as a justification for the development of a management guideline for medical practitioners. A guideline for multidisciplinary care of home ventilated MND patients will be proposed.
Study objectives: This study was aimed at assessing health-related quality of life (HRQL) in patients with chronic respiratory failure (CRF) and long-term survival following prolonged intensive care mechanical ventilation. Design: Observational cohort study. Setting: Patients with CRF who had been transferred to our specialized weaning centre due to prolonged mechanical ventilation (>14 days) and weaning failure. Patients and participants: Out of 87 long-term survivors (>6 months), 73 patients (mean age: 60.3±13.6 years, chronic obstructive pulmonary disease (COPD, 43%), thoraco-restrictive (21%) or neuromuscular disorders (15%), various chronic diseases (22%)) returned the MOS 36-Item Short-Form Health Status Survey (SF-36) and the St. George's respiratory questionnaire (SGRQ). Measurements and results The total ventilation time was 38.7±45.9 days. The time between discharge from ICU and HRQL assessment was 31.0±22.2 months. Physical health was markedly reduced compared to general population norm, but mental health was mildly impaired. HRQL was comparable to patients with stable CRF receiving non-invasive ventilation who did not need prolonged invasive MV. In addition, general HRQL was better in patients with restrictive respiratory disease compared to patients with neuromuscular diseases (P<0.05). Physiological parameters such as blood gases or lung function parameters were not correlated to any HRQL measurements. Conclusions: In patients with CRF surviving prolonged ventilation on ICU, the presence of CRF itself is the major determinant of HRQL. Here, the underlying cause of CRF is the major factor which determines the degree of HRQL impairment with patients suffering from restrictive ventilatory disorders reporting the best HRQL when compared to patients with COPD or neuromuscular diseases. Despite severe physical handicaps due to CRF mental health is only mildly compromised.
Background: Quality control procedures vary considerably among the providers of equipment for home mechanical ventilation (HMV). Methods: A multicentre quality control survey of HMV was performed at the home of 300 patients included in the HMV programmes of four hospitals in Barcelona. It consisted of three steps: (1) the prescribed ventilation settings, the actual settings in the ventilator control panel, and the actual performance of the ventilator measured at home were compared; (2) the different ventilator alarms were tested; and (3) the effect of differences between the prescribed settings and the actual performance of the ventilator on non-programmed readmissions of the patient was determined. Results: Considerable differences were found between actual, set, and prescribed values of ventilator variables; these differences were similar in volume and pressure preset ventilators. The percentage of patients with a discrepancy between the prescribed and actual measured main ventilator variable (minute ventilation or inspiratory pressure) of more than 20% and 30% was 13% and 4%, respectively. The number of ventilators with built in alarms for power off, disconnection, or obstruction was 225, 280 and 157, respectively. These alarms did not work in two (0.9%), 52 (18.6%) and eight (5.1%) ventilators, respectively. The number of non-programmed hospital readmissions in the year before the study did not correlate with the index of ventilator error. Conclusions: This study illustrates the current limitations of the quality control of HMV and suggests that improvements should be made to ensure adequate ventilator settings and correct ventilator performance and ventilator alarm operation.
Purpose: To document and explain the beneficial effects of non-invasive ventilation in correcting hypoxemia and hypoventilation in severe chronic obstructive pulmonary disease, during spinal anesthesia in the lithotomy position. Clinical features: A morbidly obese patient with severe chronic obstructive pulmonary disease underwent prostate surgery in the lithotomy position under spinal anesthesia. Hypoxemia was encountered during surgery, and a profound decrease of forced vital capacity associated with alveolar hypoventilation and ventilation/perfusion mismatching were observed. In the operating room, an M-mode sonographic study of the right diaphragm was performed, which confirmed that after spinal anesthesia and assuming the lithotomy position, there was a large decrease (-30%) in diaphragmatic excursion. Hypoxemia and alveolar hypoventilation were successfully treated with non-invasive positive pressure ventilation. Conclusions: Intraoperative application of non-invasive positive pressure ventilation improved diaphragmatic excursion and overall respiratory function, and reduced clinical discomfort in this patient.
Rationale: Respiratory failure after extubation and reintubation is associated with increased morbidity and mortality. Objectives: To assess the efficacy of noninvasive ventilation in averting respiratory failure after extubation in patients at increased risk. Methods: A prospective randomized controlled trial was conducted in 162 mechanically ventilated patients who tolerated a spontaneous breathing trial after recovery from the acute episode but had increased risk for respiratory failure after extubation. Patients were randomly allocated after extubation to receive noninvasive ventilation for 24 h (n = 79), or conventional management with oxygen therapy (control group, n = 83). Measurements and Main Results: The primary end-point variable was the decrease in respiratory failure after extubation. In the noninvasive ventilation group, respiratory failure after extubation was less frequent (13, 16 vs. 27, 33%; p = 0.029) and the intensive care unit mortality was lower (2, 3 versus 12, 14%; p = 0.015). However, 90-d survival did not change significantly between groups. Separate analyses of patients without and with hypercapnia (arterial CO2 tension greater than 45 mm Hg) during the spontaneous breathing trial showed that noninvasive ventilation improved intensive care unit mortality (0 vs. 4, 18%; p = 0.035) and 90-d survival (p = 0.006) in hypercapnic patients only; of them, 98% had chronic respiratory disorders. Conclusions: The early use of noninvasive ventilation averted respiratory failure after extubation and decreased intensive care unit mortality among patients at increased risk. The beneficial effect of noninvasive ventilation in improving survival of hypercapnic patients with chronic respiratory disorders warrants a new prospective clinical trial.
Nebulization associated with noninvasive ventilation is used in emergency services and intensive care units. PURPOSES: To compare pulmonary radioaerosol deposition during jet nebulization associated to noninvasive ventilation versus spontaneous breathing nebulization; to measure the rate of lung depuration and the correlation between lung deposition, inspiratory flow and tidal volume (V(t)) using scintigraphy. SUBJECTS: Thirteen healthy volunteers (with normal spirometry), mean age (23.3+/-1.49) years, body mass index 21.2+/-2.3kg/m(2). METHODS: Nebulization was performed in spontaneous breathing and associated with bi-level noninvasive ventilation (inspiratory pressure=12cm H(2)O, expiratory pressure=5cm H(2)O). The radioaerosol used in the nebulization was technetium (Tc99m) with diethylene triamine penta acetic acid, generated over a period of 9min in a jet nebulizer. Analysis was performed through scintigraphy. Statistical analysis was performed by analysis of variance (for repeated measures), Bonferroni method, Student's t-test and Person's correlation. RESULTS: There was a decrease in radioaerosol lung deposition with nebulization associated to noninvasive ventilation (mean counts in spontaneous breathing 200,510+11,012 and mean counts in noninvasive ventilation 106,093+2811 (P<0.001). During spontaneous breathing nebulization there was a significant correlation between V(t) and radioaerosol deposition (r=0.565, P<0.05), also between inspiratory flow and radioaerosol deposition in the lungs (r=0.141, P<0.05). However, there was no correlation between V(t) and pulmonary deposition of radioaerosol in bi-level noninvasive ventilation nebulization (r=0.082). CONCLUSION: During nebulization with noninvasive ventilation in healthy volunteers, there was an increase in V(t) associated to a higher inspiratory flow rate, without resulting in a significant increase in pulmonary radioaerosol deposition.
Background: Patients suffering from post-polio syndrome still contribute significantly to the number of patients with chronic respiratory failure requiring home mechanical ventilation (HMV). Many of these patients are treated either with invasive (tracheostomy) or non-invasive (nasal mask) controlled mechanical ventilation i.e. volume-controlled ventilation (VCV). In this group of patients, we have previously shown that bi-level pressure support ventilation (bi-level PSV) decreases the oxygen cost of breathing. The aim of this study was to compare the effect of bi-level PSV, with special regard to the adequacy of ventilation and the oxygen cost of breathing, during the patients' ordinary VCV and spontaneous breathing. Methods: Eight post-polio patients on nocturnal VCV were investigated. Five of them were tracheostomized and three of them used a nasal mask. Work of breathing was analysed by assessing differences in oxygen consumption (VO(2)) using indirect calorimetry. Blood gases were obtained regularly to assess adequacy of ventilation. Results: Bi-level PSV decreases the oxygen cost of breathing in post-polio patients with respiratory failure without decreasing ventilation efficiency. Furthermore, PaCO(2) decreased significantly using this mode of ventilation (P < 0.05). Conclusion: In this study, it was shown that bi-level PSV reduces the oxygen cost of breathing and gave a significant decrease in PaCO(2) in PPS patients. These data suggest that bi-level PSV ventilation maintains adequate ventilation in patients who suffer from post-polio syndrome with respiratory failure.
The home ventilator market has grown in size and complexity.Are common home ventilators user-friendly for trained ICU physicians?Eleven ventilator models were tested by 13 ICU physicians without practical experience in home mechanical ventilation. Six tests were defined (start up, "unlocking", mode and setting recognition, mode change, pressure setting, alarm). For each test, the physicians were timed and their performance compared to a reference time established by a technician. The physicians also had to rate their global assessment of each machine on a visual analog scale.The startup test was the only test for which there was no significant difference between the physicians and the technician, except for two ventilators. The physicians were slower than the technician to unlock the ventilator and change the ventilatory mode, with some complete failures during these tests and heterogeneous results between physicians and between ventilators. Mistakes occurred in close to 50% of cases during the ventilatory mode and settings recognition test. The mean time for the most rapid of the physicians for all the tests was 58+/-53 s, against 15+/-9 s for the technician.Trained ICU physicians perform poorly when confronted with home mechanical ventilators without specific prior training. We hypothesise that the user-friendliness of home ventilators for other categories of users might be questionable.
Non-invasive positive pressure ventilation (NIV) treatment of advanced respiratory insufficiency prolongs survival in ALS. To investigate the critical question of whether earlier initiation of NIV might provide additional benefit, a randomized trial with an appropriate placebo is needed. This study evaluated sub-therapeutic (sham) continuous positive airway pressure as a potential placebo. In a single-blind design, 40 ALS patients with forced vital capacity>50% were randomized to receive 30 seconds (s) of either active NIV, with 8 cm H2O inspiratory and 4 cm H2O expiratory pressure, or sham NIV with<1 cm of H2O continuous positive airway pressure at the mask. A questionnaire was then used to assess whether subjects thought that they had received a 'real' or 'pretend' treatment trial. The subjects' median age was 60.5 years, and 38% were female. Twelve of 20 subjects (60%) who received active NIV and 7 (35%) of the 20 subjects who received sham thought that they had tried the active treatment (p = 0.11). Only 8 (20%) of all subjects were confident about their determination that they had received 'real' or 'pretend' NIV. Thus, sub-therapeutic (sham) continuous positive airway pressure is a promising placebo control for NIV trials in ALS.
This systematic review comprises an objective appraisal of the evidence in regard to the management of respiration in patients with motor neuron disease (MND/ALS). Studies were identified through computerised searches of 32 databases. Internet searches of websites of drug companies and MND/ALS research web sites, 'snow balling' and hand searches were also employed to locate any unpublished study or other 'grey literature' on respiration and MND/ALS. Since management of MND/ALS involves a number of health professionals and care workers, searches were made across multiple disciplines. No time frame was imposed on the search in order to increase the probability of identifying all relevant studies, although there was a final limit of March 2005. Recommendations for patient and carer-based guidelines for the clinical management of respiration for MND/ALS patients are suggested on the basis of qualitative analyses of the available evidence. However, these recommendations are based on current evidence of best practice, which largely comprises observational research and clinical opinion. There is a clear need for further evidence, in particular randomised and non-randomised controlled trials on the effects of non-invasive ventilation and additional larger scale cohort studies on the issues of initial assessment of respiratory symptoms, and management and timing of interventions.
ABSTRACT : INTRODUCTION : We conducted the present study to investigate the potential beneficial and adverse effects of continuous positive airway pressure (CPAP) compared with bi-level positive airway pressure (BiPAP) noninvasive ventilation in patients with cardiogenic pulmonary oedema. METHOD : We included randomized controlled studies comparing CPAP and BiPAP treatment in patients with cardiogenic pulmonary oedema from the Cochrane Controlled Trials Register (2005 issue 3), and EMBASE and MEDLINE databases (1966 to 1 December 2005), without language restriction. Two reviewers reviewed the quality of the studies and independently performed data extraction. RESULTS : Seven randomized controlled studies, including a total of 290 patients with cardiogenic pulmonary oedema, were considered. The hospital mortality (relative risk [RR] 0.76, 95% confidence interval [CI] 0.32-1.78; P = 0.52; I2 = 0%) and risk for requiring invasive ventilation (RR 0.80, 95% CI 0.33-1.94; P = 0.62; I2 = 0%) were not significantly different between patients treated with CPAP and those treated with BiPAP. Stratifying studies that used either fixed or titrated pressure during BiPAP treatment and studies involving patients with or without hypercapnia did not change the results. The duration of noninvasive ventilation required until the pulmonary oedema resolved (weighted mean difference [WMD] in hours = 3.65, 95% CI -12.12 to +19.43; P = 0.65, I2 = 0%) and length of hospital stay (WMD in days = -0.04, 95% CI -2.57 to +2.48; P = 0.97, I2 = 0%) were also not significantly different between the two groups. Based on the limited data available, there was an insignificant trend toward an increase in new onset acute myocardial infarction in patients treated with BiPAP (RR 2.10, 95% CI 0.91-4.84; P = 0.08; I2 = 25.3%). CONCLUSION : BiPAP does not offer any significant clinical benefits over CPAP in patients with acute cardiogenic pulmonary oedema. Until a large randomized controlled trial shows significant clinical benefit and cost-effectiveness of BiPAP versus CPAP in patients with acute cardiogenic pulmonary oedema, the choice of modality will depend mainly on the equipment available.
Technological dependency is defined as a short or long-term reliance on machines and techniques to evaluate, satisfy or resolve health problems. In nursing technological dependency has been explored in the context of caring. Hitherto it has been maintained that technology and caring are contradictory, but a more prominent view is that technology and caring can and must be reconciled to provide high-quality care. This study describes patients' and families' experience of long-term home treatment with noninvasive ventilation during sleep with or without additional oxygen therapy. Considering the potential burden of undergoing this treatment the research question is: What is patients' and families' experience of being dependent on technical breathing assistance during sleep? The methodological approach draws from interpretive phenomenology and narrative analysis. Participants were six patients aged 45-70, five spouses and one daughter. Data, generated through two 1-hour semi-structured interviews with each pair of participants, were analysed into themes. Results are presented by the following narratives: (i) mixed blessing: life-saving treatment - meaningless exertion; (ii) compassion and understanding central amid use of complex machines; (iii) listening to the body; (iv) wanting to be seen as healthy; (v) dominance of technological thinking; and (vi) sustained work in maintaining the treatment. It is concluded that being dependent on technical breathing assistance during sleep, with or without oxygen, was a major life event for participants. The treatment was experienced as constraining and intrusive, particularly at the beginning, but concurrently it dramatically relieved difficulties for most participants. Regardless of its usefulness it provoked questions on purpose, indicating that the way to implement the treatment is crucial. Professionals need to pay close attention to how they introduce noninvasive ventilation technique, putting caring concern and respect for unique needs of patients and their families at the forefront.
Background: Patients with acute pancreatitis (AP) who require mechanical ventilation have high morbidity and mortality rates. Noninvasive positive pressure ventilation (NPPV) delivered through a mask has become increasingly popular for the treatment of acute respiratory failure (ARF) and may limit some mechanical ventilation complications. Objectives: The purpose of this retrospective, observational study was to evaluate our clinical experience with the use of NPPV in AP patients with ARF. Methods: From 1997 to 2003, we documented clinical data, gas exchange and outcome of the 62 AP patients admitted to our intensive care unit. Patients who benefited from NPPV (success) were compared with those who failed (intubated). Results: Twenty-nine patients were intubated at admission and 5 did not develop ARF. Of the 28 patients treated with NPPV, 15 were not intubated (54%). Both groups had a similar PaO2/FiO2 ratio (142 ± 21 vs. 133 ± 20; p = 0.127) and severity of illness (Ranson and Balthazar scores). Presence of atelectasis, bilateral alveolar infiltrates and abdominal distension were associated with failure of NPPV. Oxygenation improved and respiratory rate decreased significantly only in the success group. Additionally, the length of stay at the intensive care unit was significantly lower in the success group. Conclusion: NPPV is feasible and safe to treat ARF in selected patients with AP who require ventilatory support.
In spite of emerging evidence of therapeutic benefit from non- invasive positive pressure ventilation (NPPV), only a minority of ALS patients use this therapy. We examined factors which correlate with use of NPPV in ALS patients. Data were analyzed from the ALS CARE Database on the use of NPPV in patients with FVC less than 50% of predicted and probable or definite ALS based on modified El Escorial criteria. Of the 403 eligible patients, 146 (36%) used NPPV. NPPV compliance was strongly correlated with symptoms of dyspnea and orthopnea as well as with the use of other therapies including PEG tubes, augmentative speech devices, and riluzole. Male gender and household income >$80,000 were also associated with higher NPPV use. There was no correlation between age, race, type of insurance, forced vital capacity, duration of symptoms, ALSFRS-R, caregiver burden or quality of life with the use of NPPV. These data suggest that the factors which are most closely associated with NPPV utilization are symptomatic orthopnea and dyspnea. The findings may be useful in designing prospective studies to examine the factors which might explain the underutilization of NPPV and the optimal use of this treatment.
Severe, acute exacerbations of chronic obstructive pulmonary disease are a common presentation to emergency departments in the UK. In this group of patients, clinical examination can be unreliable in excluding a pneumothorax. With the increasing role of non-invasive positive pressure ventilation in these cases, we present a case report that highlights the need for an urgent chest X-ray prior to commencement of non-invasive positive pressure ventilation.
INTRODUCTION: In chronic alveolar hypoventilation, previous studies of selected patient groups have shown that nocturnal home mechanical ventilation (HMV) may result in improvements in chronic blood gas disturbances during daytime spontaneous breathing. We wished to examine the effects of this treatment in a large sample of non-selected patients prospectively followed up, in a national multicentric register. MATERIAL: A total of 288 patients from a broad diagnostic spectrum were studied. We looked at the blood gases and vital capacity before the patients elected for initiation of HMV and at the first register-recorded follow-up after 6-24 months. RESULTS: We found statistically significant improvements in PO(2) and PCO(2) (approximately 1 kPa in both) and in base excess, but no changes in vital capacity or calculated alveolo-arterial gradient. All changes were independent of the observation period and only weakly diagnose-related. DISCUSSION: Our findings extend those of previous studies, showing a relatively early and apparently stable improvement in blood gases after starting and continuing nocturnal HMV. The equal extent of the improvements in blood gases among all the diagnostic groups including the neurological patients with progressive diseases was unexpected. CONCLUSION: In 288 patients starting nocturnal HMV electively we found significant improvements in daytime blood gases after 6-24 months. There were no changes in vital capacity or calculated alveolo-arterial gradient.
PURPOSES: Little information is available on the utilization of noninvasive positive-pressure ventilation (NPPV) in the United States. Accordingly, we performed a survey on the use of NPPV at acute care hospitals in a region of the United States to determine variations in utilization and between hospitals, the reasons for lower rates of utilization, and the techniques used for application. METHODS: Using survey methodology, we developed a questionnaire consisting of 19 questions and distributed it by mail to directors of respiratory care at all 82 acute care hospitals in Massachusetts and Rhode Island. Nonresponders were contacted by phone to complete the survey. Responses were analyzed using standard statistics, including t tests and Mann-Whitney U tests where appropriate. RESULTS: We obtained responses from 71 of the 82 hospitals (88%). The overall utilization rate for NPPV was 20% of ventilator starts, but we found enormous variation in the estimated utilization rates among different hospitals, from none to > 50%. The top two reasons given for lower utilization rates were a lack of physician knowledge and inadequate equipment. In the 19 hospitals that provided detailed information, COPD and congestive heart failure constituted 82% of the diagnoses of patients receiving NPPV, but NPPV was still used in only 33% of patients with these diagnoses receiving any form of mechanical ventilation. CONCLUSIONS: The utilization rates for NPPV vary enormously among different acute care hospitals within the same region. The perceived reasons for lower utilization rates include lack of physician knowledge, insufficient respiratory therapist training, and inadequate equipment. Educational programs directed at individual institutions may be useful to enhance utilization rates.
GOALS OF WORK: The study was conducted to determine the usefulness and efficacy of non-invasive ventilation (NIV) in cancer patients with "life-support techniques limitation" admitted for an acute respiratory distress, in terms of intensive care unit (ICU) and hospital discharges. PATIENTS AND METHODS: A total of 18 consecutive cancer patients (17 with solid tumours and one with haematological malignancy) with "life-support techniques limitation" in acute respiratory failure and who benefited from NIV were included. NIV was provided with a standard face mask by the BiPAP Vision ventilator (Respironics Inc.). Variables related to the demographic parameters, SAPS II score, cancer characteristics, intensive care data and hospital discharge were recorded. MAIN RESULTS: Complications leading to NIV were hypoxemic respiratory failure in 11 patients and hypercapnic respiratory failure in seven. Total median duration of NIV was 29 h. NIV was applied during a median of 2.5 days with a median of 16 h per day. Total median ICU stay was 7 days (range 1-21). Fourteen and ten patients were discharged from ICU and from hospital, respectively. CONCLUSION: NIV appears to be an effective ventilation support for cancer patients with "life-support techniques limitation".
STUDY OBJECTIVE: Two modes of noninvasive home mechanical ventilation (NIHMV) with volumetric ventilators were compared in patients with chronic respiratory failure. DESIGN: Retrospective, parallel-group, comparative study. SETTING: Third-level teaching Hospital in Barcelona (Spain). PATIENTS AND METHODS: We studied 110 patients with chronic hypercapnic respiratory failure secondary to neuromuscular disease, kyphoscoliosis or post-tuberculosis sequelae, starting NIHMV with volumetric ventilators. The assist/control (A/C) ventilation mode was used in 45 patients and the control (C) mode in 65 patients. Clinical characteristics, pulmonary function results and arterial blood gas findings were assessed in each patient before establishing ventilation and at 6 and 12 months after. The patient's satisfaction with ventilation, the time required for adaptation, and compliance with the prescription were also assessed. MEASUREMENTS AND RESULTS: Significant improvements in PaO(2) and PaCO(2) (P<0.001) were found at 6 and 12 months with both modes of mechanical ventilation. There were no significant differences between the two modes for pulmonary function or blood gas parameters with the exception of maximum inspiratory pressure (MIP) in patients receiving the C mode, which was significantly different as compared to the baseline value after 12 months of use (mean+/-sd: 36.6+/-14.8 and 44.7+/-24.2cmH(2)O, respectively; P=0.010). No significant differences were found in adaptation, compliance with ventilation or patient satisfaction between the two modes studied. CONCLUSIONS: According to several factors analysed, results with the A/C or C mode used with volumetric ventilators appear to be comparable in patients with chronic respiratory disease receiving NIHMV. Choice of mode will depend on the acquired experience of the prescribing physicians in each centre.
BACKGROUND: Noninvasive ventilation (NIV) reduces mortality and improves some aspects of quality of life (QoL) in ALS. However, concerns remain that progressive disability may negate these benefits and unnecessarily burden caregivers. METHODS: Thirty-nine patients requiring NIV were offered treatment. Twenty-six were established on NIV, but 13 declined or could not tolerate NIV. Fifteen patients without respiratory muscle weakness (RMW) but with similar ALS severity and age were studied in parallel. Caregivers of 21 NIV, 7 untreated, and 10 patients without RMW participated. Patients and caregivers had detailed QoL measurements for 12 months. NIV patients underwent cognitive testing before and after treatment. RESULTS: RMW correlated with lower QoL. The median survival of untreated patients (18 days; 95% CI 11 to 25 days) was shorter than for NIV patients (298 days; 95% CI 192 to 404 days) and non-RMW patients (370 days; 95% CI 278 to 462 days; log rank test [2 df] = 81, p = 0.00001). A wide range of QoL measures improved within 1 month of starting NIV, and improvements were maintained for 12 months. QoL of non-RMW patients declined as RMW progressed. Caregivers of NIV and non-RMW patients showed similar increases in burden, but NIV patient caregivers developed a deterioration in the Short Form-36 Vitality score. No improvements were found on measures of learning and recall in the NIV patients. CONCLUSIONS: Respiratory muscle weakness has a greater impact on quality of life (QoL) than overall ALS severity. Noninvasive ventilation (NIV) improves QoL despite ALS progression. NIV has no impact on most aspects of caregiver QoL and does not significantly increase caregiver burden or stress.
Non-invasive ventilation (NIV) is a safe, versatile and effective technique that can avert side effects and complications associated with endotracheal intubation. The success of NIV relies on several factors, including the type and severity of acute respiratory failure, the underlying disease, the location of treatment, and the experience of the team. The time factor is also important. NIV is primarily used to avert the need for endotracheal intubation in patients with early-stage acute respiratory failure and post-extubation respiratory failure. It can also be used as an alternative to invasive ventilation at a more advanced stage of acute respiratory failure or to facilitate the process of weaning from mechanical ventilation. NIV has been used to prevent development of acute respiratory failure or post-extubation respiratory failure. The number of days of NIV and hours of daily use differ, depending on the severity and course of the acute respiratory failure and the timing of application. In this review article, we analyse, compare and discuss the results of studies in which NIV was applied at various times during the evolution of acute respiratory failure.