Home Care NetWork
Home Care Literature Review: July - December 2006
Mechanical Ventilation:
Simonds AK. Recent advances in respiratory care for neuromuscular disease. Chest 2006; 130:1879-1886
This review article summarizes the state-of-the-art of noninvasive ventilation in the care of patients with neuromuscular disease. Evidence is presented that noninvasive ventilation allows some patients with nonprogressive pathology to live to nearly normal life expectancy and favorably impact survival in patients with slowly progressive conditions (eg, Duchenne muscular dystrophy). Finally, the author makes a case for improved symptoms, and perhaps survival, in patients with rapidly deteriorating disease (eg, amyotrophic lateral sclerosis). This is an interesting review of the state of the art. As usual in this area, much of the information comes from Europe.
Schonhofer B, Polkey MI, Suchi S, Kohler D. Effect of home mechanical ventilation on inspiratory muscle strength in COPD. Chest 2006; 130:1834-1838
This German case series tested the hypothesis that low-frequency diaphragm fatigue is responsible for chronic hypercapnic respiratory failure in patients with COPD remains by majoring the twitch transdiaphragmatic pressure (Tw Pdi) in response to phrenic nerve stimulation in 25 patients with chronic hypercapnic respiratory failure PaCO2, 55.2 +/- 5.2 mm Hg, mean +/- SD) due to COPD before and 2 months after the initiation of noninvasive mechanical ventilation (pressure-cycled ventilation with inspiratory positive airway pressure of 19.0 +/- 2.5 cm H2O). Compliance with noninvasive mechanical ventilation was good (median machine usage = 7.1 h per night), PaCO2decreased from 55.2 +/- 5.2 to 48.8 +/- 5.9 mm Hg (p < 0.001), and PaO2 increased from 53.1 +/- 5.9 to 57.7 +/- 7.0 mm Hg (p = 0.007), but neither mean Tw Pdi (baseline 11.1 +/- 6.6 cm H2O vs 11.7 +/- 7.2 cm H2O) nor maximal static inspiratory mouth pressure (44.3 +/- 15.9 cm H2O vs 46.5 +/- 19.7 cm H2O) improved. While this is only a case series, it does suggest that chronic diaphragmatic fatigue is not an important factor in chronic hypercapnic respiratory failure associated with COPD and that home noninvasive mechanical ventilation does not effectively unload the diaphragm.
Gustafson T, Franklin KA, Midgren B, Pehrsson K, Ranstam J, Strom K. Survival of patients with kyphoscoliosis receiving mechanical ventilation or oxygen at home. Chest 2006; 130:1828-1833
This Swedish prospective case series followed patients for various lengths of time with nonparalytic kyphoscoliosis, defined as unrelated to neuromuscular disease, who started long-term oxygen therapy (LTOT) or home mechanical ventilation (HMV) between 1996 and 2006 to determine the death rate with each mode of therapy. No patient was lost to follow-up. One hundred patients received HMV, and 144 patients received LTOT alone. After adjusting for age, gender, concomitant respiratory diseases, and blood gas levels, patients on HMV had a longer survival (hazard ratio of 0.30, 95% confidence interval, 0.18 to 0.51). This case series provides a reasonable rationale for using home mechanical ventilation in patients with kyphoscoliosis. It is unlikely that a large-scale, long-term, randomized clinical trial comparing these two modes of therapy— or placebo for that matter—will be carried out.
Laub M, Midgren B. The effects of nocturnal home mechanical ventilation on daytime blood gas disturbances. Clin Physiol Funct Imaging 2006; 26:79-82
This Swedish large database analysis of the records of 288 patients with chronic alveolar hypoventilation on nocturnal home mechanical ventilation who were enrolled in a national multicenter register found small but statistically significant improvements in PaO2 and PCaO2, but no changes in vital capacity or calculated alveolo-arterial gradient. These changes were small but may be clinically significant. This is an interesting analysis in that it represents a "real-life" picture of the impact up nocturnal home mechanical ventilation in these patients.
Rabkin JG, Albert SM, Tider T, Del Bene ML, O'Sullivan I, Rowland LP, Mitsumoto H. Predictors and course of elective long-term mechanical ventilation: a prospective study of ALS patients. Amyotroph Lateral Scler 2006; 7:86-95
This descriptive study of 72 hospice-eligible patients with amyotrophic lateral sclerosis compared those who opted for tracheostomy and long-term mechanical ventilation (LTMV), N =14, with those who did not, and found that at entry those who chose LTMV were younger, more likely to have young children, more education, higher household incomes on average, higher levels of optimism, more positive appraisals of their ability to function in daily life, their physical health and overall life satisfaction. None were depressed, compared with 26% of those who later refused LTMV. After an average of 33 months on LTMV, no patient had requested termination of ventilation, but only about half retained high levels of optimism and enjoyment of daily life, independent of residence (home vs facility). Two patients expressed interest in hastening death, and seven identified future circumstances that would render life intolerable, but none had asked to terminate ventilation, despite disease progression. Spousal caregivers reported a significant emotional burden associated with LTMV and most, but not all, continued to express satisfaction with care-giving. This small but interesting report has a great deal of information and insights into the decisions for long-term mechanical ventilation in this terrible disease. It also emphasizes that impact on caregivers always needs to be factored into these decisions.
Farre R, Navajas D, Prats E, Marti S, Guell R, Montserrat JM, Tebe C, Escarrabill J. Performance of mechanical ventilators at the patient's home: a multicentre quality control study. Thorax 2006; 61:400-404. Epub 2006 Feb 7
The Spanish survey of four hospitals in Barcelona found significant differences between actual, set, and prescribed values of ventilator variables for both volume and pressure preset ventilators (a discrepancy between the prescribed and actual measured main ventilator variable—minute ventilation or inspiratory pressure) of more than 20% in 13% of patients and 30% in 4%. There were significant problems with the alarms for power off, disconnection, or obstruction. Surprisingly, the number of nonprogrammed hospital readmissions in the year before the study did not correlate with the index of ventilator error. This group is very experienced in managing in-home mechanical ventilation, so these results are somewhat disconcerting. It would be very interesting to see a similar study in United States.
Munoz X, Crespo A, Marti S, Torres F, Ferrer J, Morell F. Comparative study of two different modes of noninvasive home mechanical ventilation in chronic respiratory failure. Respir Med 2006; 100:673-681. Epub 2005 Sep 27
This Spanish retrospective analysis of the outcomes of 110 patients with chronic hypercapnic respiratory failure secondary to neuromuscular disease, kyphoscoliosis, or posttuberculosis sequela, treated with noninvasive home mechanical ventilation using assist/control ventilation mode (45 patients) or control mode (65 patients) found significant improvements in PaO2 and PaCO2 (P<0.001) at 6 and 12 months, with both modes and no important difference between the modes. It appears that the mode of ventilation is less important than the use of the ventilator itself in this study.
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