John R. Bach

Criteria for Extubation and Tracheostomy Tube Removal for Patients With Ventilatory Failure : A Different Approach to Weaning

The purpose of this study was to prospectively compare parameters that might predict successful translaryngeal extubation and tracheostomy tube decannulation. Irrespective of ventilatory function, 62 extubation/decannulation attempts were made on 49 consecutive patients with primarily neuromuscular ventilatory insufficiency who satisfied criteria. Thirty-four patients required 24-h ventilatory support. Noninvasive intermittent positive pressure ventilation (IPPV) was substituted as needed for IPPV via translaryngeal or tracheostomy tubes. Successful decannulation was defined as extubation or decannulation and site closure with no consequent respiratory symptoms or blood gas deterioration for at least 2 weeks. Failure was defined by the appearance of respiratory distress and decreases in vital capacity and oxyhemoglobin saturation despite use of noninvasive IPPV and assisted coughing. The independent variables of age, extent of predecannulation ventilator use, vital capacity, and peak cough flows (PCF) were studied to determine their utility in predicting successful extubation and decannulation. Only the ability to generate PCF greater than 160 L/min predicted success, whereas inability to generate 160 L/min predicted the need to replace the tube. All 43 attempts on patients with PCF greater than 160 L/min succeeded; all 15 attempts on patients with PCF below 160 L/min failed; and of 4 patients with PCF of 160 L/min, 2 succeeded and 2 failed. We conclude that the ability to generate PCF of at least 160 L/min is necessary for the successful extubation or tracheostomy tube decannulation of patients with neuromuscular disease irrespective of ability to breathe.

Prevention of Pulmonary Morbidity for Patients With Duchenne Muscular Dystrophy

STUDY OBJECTIVE To evaluate the effects of a new respiratory management protocol on respiratory morbidity and hospitalization rates for patients with Duchenne muscular dystrophy (DMD). DESIGN A retrospective cohort study. METHODS Using a protocol in which oxyhemoglobin desaturation was prevented or reversed by the use of noninvasive intermittent positive pressure ventilation (IPPV) and assisted coughing as needed, the hospitalization rates and days for 24 protocol DMD ventilator users were compared with those of 22 nonprotocol DMD tracheostomy IPPV users. RESULTS The 22 conventionally managed patients were hospitalized a mean of 72.2+/-112 days when undergoing tracheostomy. This included a 16.1+/-5.4-day period of translaryngeal intubation. The 24 protocol patients were hospitalized a mean of 6.0+/-2.4 days (p<0.005) when beginning ventilator use. Over their next 126.2 patient-years of ventilator use, the 24 protocol patients had significantly lower rates of hospitalization (p<0.008) and hospitalization days (p<0.005) than had the tracheostomy IPPV users over a 167.2 patient-year period. This is true although 14 of the 24 protocol patients went on to require 24-h noninvasive IPPV for 4.5+/-3.6 years. Five of the 14 have yet to be hospitalized. CONCLUSION The use of inspiratory and expiratory aids can prolong survival while significantly decreasing the pulmonary morbidity and hospitalization rates associated with conventional resort to tracheostomy IPPV.

Clinical Investigations in Critical CareCriteria for Extubation and Tracheostomy Tube Removal for Patients With Ventilatory Failure: A Different Approach to Weaning

The purpose of this study was to prospectively compare parameters that might predict successful translaryngeal extubation and tracheostomy tube decannulation. Irrespective of ventilatory function, 62 extubation/decannulation attempts were made on 49 consecutive patients with primarily neuromuscular ventilatory insufficiency who satisfied criteria. Thirty-four patients required 24-h ventilatory support. Noninvasive intermittent positive pressure ventilation (IPPV) was substituted as needed for IPPV via translaryngeal or tracheostomy tubes. Successful decannulation was defined as extubation or decannulation and site closure with no consequent respiratory symptoms or blood gas deterioration for at least 2 weeks. Failure was defined by the appearance of respiratory distress and decreases in vital capacity and oxyhemoglobin saturation despite use of noninvasive IPPV and assisted coughing. The independent variables of age, extent of predecannulation ventilator use, vital capacity, and peak cough flows (PCF) were studied to determine their utility in predicting successful extubation and decannulation. Only the ability to generate PCF greater than 160 L/min predicted success, whereas inability to generate 160 L/min predicted the need to replace the tube. All 43 attempts on patients with PCF greater than 160 L/min succeeded; all 15 attempts on patients with PCF below 160 L/min failed; and of 4 patients with PCF of 160 L/min, 2 succeeded and 2 failed. We conclude that the ability to generate PCF of at least 160 L/min is necessary for the successful extubation or tracheostomy tube decannulation of patients with neuromuscular disease irrespective of ability to breathe.

Duchenne Muscular Dystrophy: Prolongation of Life by Noninvasive Ventilation and Mechanically Assisted Coughing

Gomez-Merino E, Bach JR: Duchenne muscular dystrophy: Prolongation of life by noninvasive ventilation and mechanically assisted coughing. Am J Phys Med Rehabil 2002;81:411–415. Objective To quantitate prolongation of survival for patients with Duchenne muscular dystrophy with the use of noninvasive intermittent positive-pressure ventilation (IPPV) with and without access to a protocol involving mechanically assisted coughing. Design In this retrospective review of all patients with Duchenne muscular dystrophy visiting a neuromuscular disease clinic, patients were trained to use mouth piece and nasal IPPV and mechanically assisted coughing to maintain oxyhemoglobin saturation >94% (protocol). Survival was considered prolonged when noninvasive IPPV was required full time. Results Ninety-one of 125 patients used noninvasive IPPV part time for 1.9 ± 1.3 yr, and 51 went on to require it full time for 6.3 ± 4.6 yr. Of the 31 noninvasive IPPV users who died without access to the protocol, 20 died from respiratory causes and seven died from cardiac causes. None of the 34 full-time noninvasive IPPV users with access to the protocol underwent tracheotomy or died from respiratory complications during a period of 5.4 ± 4.0 yr, whereas three died from heart failure. Five patients with no breathing tolerance were extubated or decannulated to continuous noninvasive IPPV. Conclusions Noninvasive respiratory aids can prolong survival and permit extubation or decannulation of patients with Duchenne muscular dystrophy with no breathing tolerance.

Neuromuscular ventilatory insufficiency : Effect of home mechanical ventilator use v oxygen therapy on pneumonia and hospitalization rates

The purpose of this study was to determine rates of pneumonia and hospitalization for patients receiving oxygen therapy, patients having indwelling tracheostomy tubes, and those using tracheostomy or noninvasive methods of home mechanical ventilation. Six hundred eighty-four users of assisted ventilation for 13,751 patient-years or 19.8 years per patient were surveyed by mail and twice by telephone over a span of four years. Pneumonia and hospitalization rates were significantly higher for ventilator users with chronic obstructive pulmonary disease or with neuromuscular ventilatory insufficiency and gastrostomy tubes than for ventilator users with neuromuscular ventilatory insufficiency without gastrostomy tubes. Of the latter group, more than 90% of the pneumonias and hospitalizations were triggered by otherwise benign intercurrent upper respiratory tract infections. Oxygen therapy was associated with a significantly (P < 0.001) higher rate of pneumonias and hospitalizations than that seen for untreated patients after initial episodes of respiratory distress or during the use of either tracheostomy intermittent positive pressure ventilation or noninvasive ventilatory assistance methods. The lowest pneumonia and hospitalization rates (P < 0.001) were by full-time, noninvasive intermittent positive pressure ventilation users. We conclude that oxygen therapy is not an effective substitute for assisted ventilation for patients with primarily ventilatory insufficiency. Noninvasive ventilatory aids can be used effectively for up to full-time ventilatory support for patients with neuromuscular conditions whose bulbar muscle function is adequate to avert the need for gastrostomy tube placement.

Amyotrophic lateral sclerosis: Predictors for prolongation of life by noninvasive respiratory aids

The purpose of this study was to determine which pulmonary function variables best predicted the potential for prolonging survival of individuals with amyotrophic lateral sclerosis (ALS) by the use of physical medicine respiratory muscle aid alternatives to tracheostomy for ventilatory support and airway suctioning. The records of 27 such ALS ventilator users with less than 15 minutes of ventilator-free breathing time for a mean +/- standard deviation of 23.7 +/- 20.3 months (range, 1 to 65) were reviewed. All patients underwent measurements of vital capacity (VC), maximum insufflation capacity (MIC), MIC VC difference, forced expiratory volumes, and peak cough expiratory flows (PCEF) every 1 to 6 months, depending on rate of disease progression, until requiring 24-hour ventilatory support. The ability to generate assisted PCEF in excess of 3L/sec and the ability to hold an insufflation deeper than the VC were associated with the capacity to prolong survival by methods other than tracheostomy, whereas the extent of decrease in VC and autonomous breathing ability were not. Because the PCEF and MIC VC difference correlate with bulbar muscle function, it can be concluded that the ability to use 24-hour ventilatory support by noninvasive means is a function of residual bulbar muscle strength and is independent of VC or the extent of need for ventilatory support. Properly equipped and trained, some ALS patients can use noninvasive respiratory muscle aids to delay or eliminate the need for tracheostomy.

Maximum insufflation capacity: vital capacity and cough flows in neuromuscular disease.

OBJECTIVE To investigate the relationships between vital capacity (VC), maximum insufflation capacity (MIC), and both unassisted and assisted peak cough flows (PCFs). DESIGN The 108 patients were divided into two groups, those whose MICs were greater than their VCs (group 1) and those whose MICs could not exceed their VCs (MIC = VC, or group 2). RESULTS The MIC correlated positively with the VC for group 1 patients, but the percent increase in MIC correlated negatively with VC. Both VC and MIC correlated significantly with both unassisted and assisted PCF, respectively. Assisting the cough increased the PCF of 37 patients over a previously defined critical level of 2.7 L/sec. The MIC VC difference and percent increase in MIC also correlated significantly with the difference between unassisted and assisted PCF. Although the group 2 patients did not have true cough flows because of inability to close the glottis, their peak expiratory flows were significantly less than the unassisted and assisted PCF of the group 1 patients. CONCLUSIONS The greater the MIC VC difference, the greater the PCF, and, thereby, the ability to expel airway mucus and avert respiratory complications. The lower the VC, the greater the percent increase in MIC and the greater the percent increase in assisted PCF. Maximal insufflations are extremely important to increase PCF for patients with neuromuscular conditions who have VCs of < 1500 ml.

Cardioprotection for Duchenne’s muscular dystrophy☆☆☆★

PURPOSE To explore the use of neuroendocrine monitoring for more timely diagnosis of dilated cardiomyopathy (DCM) in Duchennes muscular dystrophy (DMD) and to determine the effects of angiotensin-converting enzyme inhibitors (ACEI) and beta-blockers on neuroendocrine levels, left ventricular diastolic diameter (LVDd), ejection fraction, and mortality rate on DMD. METHODS Eighty-five patients with DMD underwent yearly cardiac monitoring including neuroendocrine screening. Eleven patients had symptoms of DCM develop once plasma neuroendocrine levels increased. At this point the patients received ACEI for 9 to 62 months (35.8 +/- 18.4 months) and beta-blockers for 7 to 60 months (31.6 +/- 20.1 months). RESULTS The combination of ACEI and beta-blockers relieved symptoms and signs of heart failure in all 11 patients and significantly reduced atrial natriuretic protein (ANP) levels from 197.5 +/- 152.1 pg/mL to 25.5 +/- 16.2 pg/mL ( P <.002) at 15.5 +/- 8.2 months, brain natriuretic protein from 523.8 +/- 434.8 pg/mL to 59.3 +/- 24. 2 pg/mL ( P <.05) at 12.2 +/- 3.1 months (data complete for 5 patients), norepinephrine levels from 1114 +/- 689 pg/mL to 360 +/- 257 pg/mL at 20.5 +/- 9.6 months for 11 patients (P =.001), and LVDd from 65.9 +/- 9.2 mm to 63.3 +/- 6.3 mm (P =.15) at 15.0 +/- 7.4 months for 10 patients, including 3 for whom the LVDd increased by 2 to 6 mm. The combination increased left ventricular ejection fraction (LVEF) from 25.1% +/- 9.2% to 36.5% +/- 5.8% (P <.001) at 17.1 +/- 11.0 months for 10 patients. For 9 of the patients ANP levels remained lower throughout the 36.8 +/- 20.1 month course of the follow-up. Two patients had sudden severe re-elevations of ANP levels just before death from congestive heart failure after 44 and 23 months of therapy, respectively. CONCLUSION Neuroendocrine level monitoring can assist in the diagnosis of DCM in patients with DMD. Combination therapy with ACEI and beta-blockers can significantly decrease neuroendocrine activation and LVDd and reverse symptoms and signs of congestive heart failure for patients with DMD.

Clinical implications of maximal respiratory pressure determinations for individuals with duchenne muscular dystrophy

OBJECTIVE To analyze the relationship between disease progression, pulmonary volumes, respiratory muscle strength (maximum inspiratory [MIP] and expiratory [MEP] pressure), and arterial blood gases for patients with Duchenne muscular dystrophy (DMD). DESIGN An inception cohort study of pulmonary volumes, MIPs, and MEPs, correlated with age and PaCO2 levels and with each other using linear and nonlinear regression analyses. SETTING Outpatient clinic. PATIENTS Fifty-two consecutive DMD patients who presented for regular evaluations at a regional DMD center. RESULTS Maximum expiratory pressures were 47.7% +/- 10.9% of normal in the 167- to 14-year-old patients and decreased linearly thereafter (MEP% = -2.7 x age +73.8; p < .001). Declines in MEP also correlated linearly with expiratory reserve volume (p < .001) and inversely with residual volume (p < .001). By contrast, MIP was 66.3% +/- 19.0% in the 357- to 14-year-old patients and then declined to 30.2% +/- 19.5% after age 14. No linear relationships were found with age but declines did correlate linearly with inspiratory reserve volume (p < .001) and total lung capacity (p < .001). PaCO2 elevations correlated best with decreases in MIP (p < .0001) and appeared when MIP was below 30cmH2O. CONCLUSIONS Lung volume changes in DMD patients correlate with respiratory muscle weakness, and although inspiratory muscle dysfunction plays a key role in the development of chronic ventilatory insufficiency, reductions in expiratory muscle strength are the first signs of dysfunction and lead to the first episodes of respiratory failure.

The respiratory management of patients with duchenne muscular dystrophy: a DMD care considerations working group specialty article.

In 2001, the Muscular Dystrophy Community Assistance, Research and Education Amendments (MD‐CARE Act) was enacted, which directed federal agencies to coordinate the development of treatments and cures for muscular dystrophy. As part of the mandate, the Centers for Disease Control and Prevention (CDC) initiated surveillance and educational activities, which included supporting development of care considerations for Duchenne muscular dystrophy (DMD) utilizing the RAND/UCLA Appropriateness Method (RAM). This document represents the consensus recommendations of the projects 10‐member Respiratory Panel and includes advice on necessary equipment, procedures and diagnostics; and a structured approach to the assessment and management of the respiratory complications of DMD via assessment of symptoms of hypoventilation and identification of specific thresholds of forced vital capacity, peak cough flow and maximum expiratory pressure. The document includes a set of Figures adaptable as “pocket guides” to aid clinicians. This article is an expansion of the respiratory component of the multi‐specialty article originally appearing in Lancet Neurology, comprising respiratory recommendations from the CDC Care Considerations project. Pediatr. Pulmonol. 2010; 45:739–748.