Israel Medical Association Journal

Background: High frequency oscillatory ventilation based on optimal lung volume strategy is one of the accepted modes of ventilatory support for respiratory distress syndrome in very low birth weight infants. In 1999 it was introduced in our unit as the primary ventilation modality for RDS[1].

Objectives: To evaluate if the shift to HFOV[2] influenced the outcome of ventilated VLBW[3] infants in the neonatal intensive care unit of Carmel Medical Center.

Methods: Data were obtained from the medical charts of VLBW infants born at Carmel Medical Center, and late mortality data were taken from the Israel Ministry of Internal Affairs records. A retrospective analysis and a comparison with a historical control group ventilated by the conventional method were performed.

Results: A total of 232 VLBW infants with RDS were mechanically ventilated, from 1995 to 2003: 120 were ventilated using HFOV during the period 1999–2003 and 102 infants using CV[4] during 1995–1999. The mean gestational age of survivors was 27.4 ± 2 weeks in the HFOV group and 28.4 ± 2 in the conventional ventilation group (P = 0.03). The sub-sample of infants with birth weights <1000 g ventilated with HFOV showed higher survival rates than the infants in the conventional ventilation group, 53 vs. 25 (64.6% vs. 44.6%) respectively (P < 0.05). A trend for lower incidence of pulmonary interstitial emphysema was observed in the HFOV group.

Conclusions: The introduction of HFOV based on optimal lung volume strategy proved to be an efficient and safe method of ventilation support for VLBW infants in our unit.

Background: The most common and most serious complication of varicella (chickenpox) in adults is pneumonia, which can lead to severe respiratory failure. Varicella pneumonia is associated with considerable morbidity and even death.

Objectives: To summarize our experience with varicella pneumonia in terms of clinical, laboratory and radiological characteristics as well as risk factors, management and outcome.

Methods: We conducted a retrospective cohort survey in our facility from 1995 to 2008.

Results: Our cohort comprised 21 patients with varicella pneumonia, of whom 19 (90%) were men; their mean age was 35 ± 10.5 years. Nineteen patients (90%) were Bedouins and 18 (86%) were smokers. Eleven (52%) were admitted to the Medical Intensive Care Unit; 3 of them required mechanical ventilation and the remaining 10 (48%) were admitted to the general medical ward. Median length of stay was 6 ± 7.7 days. Hypoxemia and elevated lactate dehydrogenase on admission were associated with respiratory failure. Radiological manifestations were variable and nine patients exhibited characteristic findings. All but one patient were treated with acyclovir. All patients fully recovered.

Conclusions: In southern Israel varicella pneumonia is primarily a disease of young male Bedouins who are smokers. Severity ranges from mild disease to severe, resulting at times in respiratory failure requiring mechanical ventilation. Prognosis is favorable with complete recovery.

Objectives: To define the length of time required to rehabilitate and discharge these patients, and to identify predictors of a prolonged or failed discharge process.

Methods: We conducted a retrospective chart review of patients admitted to the Respiratory Rehabilitation Unit at Alyn Hospital, Jerusalem, over a 4 year period.

Results: Of the 48 patients identified, 31 (64.7%) were eventually discharged, 13 (27.1%) remained hospitalized long-term, and 4 (8.3%) died during their hospitalization. The median length of hospitalization was 10 months: 6 months for purposes of rehabilitation therapy, and 4 months thereafter to resolve the logistics of discharge. Specific family characteristics – an unemployed father (odds ratio = 4.6, P = 0.02) and an additional family member with a disability (OR[1] = 5.8, P = 0.03) – as well as ongoing mechanical ventilation at the time of discharge (OR = 5.5, P < 0.01) were found to positively correlate with a prolonged or failed discharge process.

Conclusions:  Hospitalization in a pediatric respiratory rehabilitation unit may be prolonged for both medical and non-medical reasons, with the process of discharge home being particularly difficult in certain subsets of patients. A proactive discharge policy by hospitals, improved community support services, and legislation defining the rights of home-ventilated children may facilitate more efficient discharge home of these patients.

Objectives: To minimize ventilatory limitation during training of patients with severe COPD[1] by applying bi-level positive pressure ventilation during training in order to augment training intensity (and effect).

Methods: The study group comprised 19 patients (18 males, 1 female) with a mean age of 64 ± 9 years. Mean forced expiratory volume in 1 second was 32 ± 4% of predicted, and all were ventilatory-limited (exercise breathing reserve 3 ± 9 L/min, normal >15 L/min). The patients were randomized: 9 were assigned to training with BiPAP[2] and 10 to standard training. All were trained on a treadmill for 2 months, twice a week, 45 minutes each time, at maximal tolerated load. Incremental maximal unsupported exercise test was performed before and at the end of the training period.

Results: BiPAP resulted in an increment of 94 ± 53% in training speed during these 2 months, as compared to 41 ± 19% increment in the control group (P < 0.005). Training with BiPAP yielded an average increase in maximal oxygen uptake of 23 ± 16% (P < 0.005), anaerobic threshold of 11 ± 12% (P < 0.05) and peak O₂ pulse of 20 ± 19% (P < 0.05), while peak exercise lactate concentration was not higher after training. Interestingly, in the BiPAP group, peak exercise ventilation was also 17 ± 20% higher after training (P < 0.05). Furthermore, contrary to our expectation, at any given work rate, ventilation (and tidal volume) in the BiPAP group was higher in the post-training test as compared to the pre-training test, and the end tidal partial pressure of CO₂ at 55 watts was lower, 40 ± 4 and 38 ± 4 mmHg respectively (P < 0.05). No improvement in exercise capacity was observed after this short training period in the control group.

Conclusion: Pressure-supported ventilation during training is feasible in patients with severe COPD and it augments the training effect. The improved exercise tolerance was associated with higher ventilatory response and therefore lower P_ETCO₂[3] at equal work rates after training.

______________________

[1] COPD = chronic obstructive pulmonary disease

[2] BiPAP = bi-level positive pressure ventilation

[3] P_ETCO₂ = end tidal partial pressure of CO₂
 

Objectives: To report on our initial experience over a 7 month period with an eight-bed mechanical ventilation weaning unit.

Methods: Sixty-nine patients requiring MV[1] for >10 days were admitted to the unit (nurse:patient ratio 1:4). Data collected included reason for MV, duration of hospital stay, and MVWU[2] course. Outcome results (successful weaning and mortality) were compared to those in historic controls (patients ventilated in the general wards over a 4 month period prior to the MVWU; n = 100).

Results: The mean age of the patients was 68 ± 16.6 years and hospital stay prior to MVWU admission 28.6 ± 24.2 days (range 10–72). The main reasons for MV included acute exacerbation of chronic obstructive pulmonary disease (31%) and recent pneumonia (28%). Mean MVWU stay was 13.5 ± 15.7 days (range 1–72 days). Thirty-four patients (49%) underwent tracheostomy. Fourteen patients required admission to the ICU[3] due to deterioration in their status. Twenty-nine patients (42%) were successfully weaned and discharged to the wards. A further 20 patients were transferred to the chronic ventilation unit of a regional geriatric rehabilitation hospital, where 5 were subsequently weaned and 15 required prolonged ventilation. Compared to controls (matched for age and reason for mechanical ventilation), more MVWU patients underwent successful weaning (49% vs. 12%, P < 0.001) and their mortality rate (n = 12) was significantly lower (17% vs. 88%, P < 0.001).

Conclusion: The higher level of care possible in a MVWU may result in a significantly improved rate of weaning and lower mortality. The assessment of long-term outcome in patients discharged to pulmonary rehabilitation centers requires further investigation.

______________

[1] MV = mechanical ventilation

[2] MVWU = mechanical ventilation weaning unit

[3] ICU = intensive care unit

Background: Pulmonary disease is the most frequent cause of morbidity and mortality in cystc fibrosis patients. New techniques such as non-invasive positive pressure ventilation have resulted in prolongation of life expectancy in CF[1] patients with end-stage lung disease.

Objectives: To determine the role of NIPPV[2] in CF patients awaiting lung transplantation.

Methods: Between 1996 and 2001 nine CF patients (5 females) with end-stage lung disease were treated with bi-level positive airway pressure ventilation in the "spontaneous" mode.

Results: The patients' mean age at initiation of BiPAP[3] was 15 years (range 13–40 years) and the mean duration of BiPAP usage was 8 months (range 3–16 months). Four patients underwent successful lung transplantation, three patients died while awaiting transplantation, and the remaining two are still on NIPPV while waiting for transplantation. Patients' body mass index increased significantly (P < 0.05) during BiPAP therapy (from 16.1 to 17.2 kg/m²). Blood pH, p_aCO₂, and bicarbonate improved significantly (from 7.31 to 7.38, 90.8 to 67.2 mmHg, and 48.9 to 40.3 mEq/L, respectively). Pulmonary function tests were not affected by BiPAP usage. The patients experienced a significant alleviation in morning headaches and improvement in quality of sleep (P < 0.003). There were no major complications during BiPAP usage.

Conclusions: We demonstrated that long-term NIPPV can stabilize and improve physiologic parameters such as ventilation, arterial blood gases and body mass index, as well as subjective symptoms such as sleep pattern, daily activity level, and morning headaches in CF patients with end-stage lung disease. Further prospectively controlled studies are needed to evaluate the potential of BiPAP therapy and its influence on morbidity and mortality in the post-lung transplantation period.

Background: High frequency oscillatory ventilation has proved valuable in recruiting and sustaining lung volume; the combined treatment may augment nitric oxide delivery to target vessels. NO[1] therapy lowers pulmonary resistance and improves oxygenation.

Objective: To retrospectively review data on changes in oxygenation – indicated by arterial/alveolar PO₂ ratio, oxygenation index, and outcome – in a cohort of 10 infants with hypoxemic respiratory failure in whom nitric oxide inhalation was instituted in a compassionate-use protocol after deteriorated oxygenation.

Methods: NO inhalation was administered at a range of 0.12–122 days of life using the SensorMedics system in 10 infants who developed hypoxemic respiratory failure associated with a variety of lung diseases while on HFOV[2].

Results: The infants' birthweight was 1,717 ± 1,167 g and their gestational age 31.1 ± 6.5 weeks. Mean exposure to NO inhalation was 14.2 days and ranged from 3–59 days. Oxygenation index decreased from 39.3 ± 13.2 to 12.7 ± 6.9 (P < 0.0002) after NO therapy. Despite an initial prompt response to NO inhalation, two patients died of progressive intractable respiratory failure and one term infant died of extrapulmonary complications (hypoxic ischemic encephalopathy grade III and multiorgan failure).

Conclusion: Our results indicate that the combined treatment of HFOV and NO inhalation is superior to HFOV alone for improving oxygenation in a selected cohort of infants ventilated for a variety of lung diseases.

Background: Ventilator-dependent patients represent an increasing clinical, logistic and economic burden.  An alternative solution might be monitored home care with high-tech ventilatory support systems. 

Objectives: To explore the implications of such home-care management, such as its impact on quality of life and its cost-effectiveness, and to assess the practical feasibility of this mode of home care in Israel.

Methods: We surveyed 25 partly or fully home-ventilated patients (17 males and 8 females), average age 37.6 years (range 1–72), who were treated through a home-care provider during a 2 year period.

Results: Most patients (n=18) had a neuromuscular respiratory disorder.  The average hospital stay of these patients prior to entry into the home-care program was 181.2 days/per patient.  The average home-care duration was 404.9 days/per patient (range 60–971) with a low hospitalization rate of 3.3 ± 6.5 days/per patient.  The monthly expenditure for home care of these patients was one-third that of the hospital stay cost ($3,546.9 vs. $11,000, per patient respectively).  The patients reported better quality of life in the home-care environment, as assessed by the Sickness Impact Profile questionnaire. 

Conclusions: Home ventilation of patients in Israel by home-care providers is a practical and attractive treatment modality in terms of economic benefits and quality of life.
 

Background: Acute respiratory distress syndrome is a well-recognized condition resulting in high permeability pulmonary edema associated with a high morbidity.

Objectives: To examine a 10 year experience of predisposing factors, describe the clinical course, and assess predictors of mortality in children with this syndrome.

Methods: The medical records of all admissions to the pediatric intensive care unit over a 10 year period were evaluated to identify children with ARDS¹. Patients were considered to have ARDS if they met all of the following criteria: acute onset of diffuse bilateral pulmonary infiltrates of non-cardiac origin and severe hypoxemia defined by <200 partial pressure of oxygen during ³6 cm H2O positive end-expiratory pressure for a minimum of 24 hours. The medical records were reviewed for demographic, clinical, and physiologic information including PaO2² /forced expiratory O2, alveolar–arterial O2 difference, and ventilation index.

Results: We identified 39 children with the adult respiratory distress syndrome. Mean age was 7.4 years (range 50 days to 16 years) and the male:female ratio was 24:15. Predisposing insults included sepsis, pneumonias, malignancy, major trauma, shock, aspiration, near drowning, burns, and envenomation. The mortality rate was 61.5%. Predictors of death included the PaO2/FIO2, ventilation index and A-aDO2³ on the second day after diagnosis. Non-survivors had significantly lower PaO2/FIO2 (116±12 vs. 175±8.3, P<0.001), and higher A-aDO2 (368±28.9 vs. 228.0±15.5, P<0.001) and ventilation index (43.3±2.9 vs. 53.1±18.0, P<0.001) than survivors.

Conclusions: Local mortality outcome for ARDS is comparable to those in tertiary referral institutions in the United States and Western Europe. The PaO2/FIO2, A-aDO2 and ventilation index are valuable for predicting outcome in ARDS by the second day of conventional therapy. The development of a local risk profile may allow early application of innovative therapies in this population. 

___________________________________ 

¹ARDS = acute respiratory distress syndrome

² PaO2 = partial pressure of oxygen

³A-aDO2 = alveolar–arterial O2 difference