Ventilatory muscle recruitment and work of breathing in patients with respiratory failure after thoracic surgery

Prolonged Weaning: S2k Guideline Published by the German Respiratory Society

Mechanical ventilation (MV) is an essential part of modern intensive care medicine. MV is performed in patients with severe respiratory failure caused by respiratory muscle insufficiency and/or lung parenchymal disease; that is, when other treatments such as medication, oxygen administration, secretion management, continuous positive airway pressure (CPAP), or nasal high-flow therapy have failed. MV is required for maintaining gas exchange and allows more time to curatively treat the underlying cause of respiratory failure. In the majority of ventilated patients, liberation or "weaning" from MV is routine, without the occurrence of any major problems. However, approximately 20% of patients require ongoing MV, despite amelioration of the conditions that precipitated the need for it in the first place. Approximately 40-50% of the time spent on MV is required to liberate the patient from the ventilator, a process called "weaning". In addition to acute respiratory failure, numerous factors can influence the duration and success rate of the weaning process; these include age, comorbidities, and conditions and complications acquired during the ICU stay. According to international consensus, "prolonged weaning" is defined as the weaning process in patients who have failed at least 3 weaning attempts, or require more than 7 days of weaning after the first spontaneous breathing trial (SBT). Given that prolonged weaning is a complex process, an interdisciplinary approach is essential for it to be successful. In specialised weaning centres, approximately 50% of patients with initial weaning failure can be liberated from MV after prolonged weaning. However, the heterogeneity of patients undergoing prolonged weaning precludes the direct comparison of individual centres. Patients with persistent weaning failure either die during the weaning process, or are discharged back to their home or to a long-term care facility with ongoing MV. Urged by the growing importance of prolonged weaning, this Sk2 Guideline was first published in 2014 as an initiative of the German Respiratory Society (DGP), in conjunction with other scientific societies involved in prolonged weaning. The emergence of new research, clinical study findings and registry data, as well as the accumulation of experience in daily practice, have made the revision of this guideline necessary. The following topics are dealt with in the present guideline: Definitions, epidemiology, weaning categories, underlying pathophysiology, prevention of prolonged weaning, treatment strategies in prolonged weaning, the weaning unit, discharge from hospital on MV, and recommendations for end-of-life decisions. Special emphasis was placed on the following themes: (1) A new classification of patient sub-groups in prolonged weaning. (2) Important aspects of pulmonary rehabilitation and neurorehabilitation in prolonged weaning. (3) Infrastructure and process organisation in the care of patients in prolonged weaning based on a continuous treatment concept. (4) Changes in therapeutic goals and communication with relatives. Aspects of paediatric weaning are addressed separately within individual chapters. The main aim of the revised guideline was to summarize both current evidence and expert-based knowledge on the topic of "prolonged weaning", and to use this information as a foundation for formulating recommendations related to "prolonged weaning", not only in acute medicine but also in the field of chronic intensive care medicine. The following professionals served as important addressees for this guideline: intensivists, pulmonary medicine specialists, anaesthesiologists, internists, cardiologists, surgeons, neurologists, paediatricians, geriatricians, palliative care clinicians, rehabilitation physicians, intensive/chronic care nurses, physiotherapists, respiratory therapists, speech therapists, medical service of health insurance, and associated ventilator manufacturers.

Short-Term Pulmonary Rehabilitation for a Female Patient with Chronic Scleroderma under a Single-Case Research Design

Although previously proposed that chronic scleroderma should be cared for clinically and early rehabilitation should be performed in hospital by a chest physical therapist, little evidence is currently available on its benefits. Therefore, this study demonstrated the benefits of short-term pulmonary rehabilitation during hospitalization in a female patient with chronic scleroderma. The aim of rehabilitation was to improve ventilation and gas exchange by using airway clearance, chest mobilization, and breathing-relearning techniques, including strengthening the respiratory system and the muscles of the limbs by using the BreathMax^® device and elastic bands. Gross motor function and activities of daily life were regained by balancing, sitting, and standing practices. Data on minimal chest expansion, high dyspnea, high respiratory rate, and low maximal inspiratory mouth pressure were recorded seven days before rehabilitation or at the baseline period. But there was a clinically significant improvement in dyspnea, chest expansion, maximal inspiratory mouth pressure, and respiratory rate, when compared to baseline data, which were recorded by a chest physical therapist during seven days of rehabilitation. Furthermore, physicians decided to stop using a mechanical ventilator, and improvement in functional capacity was noted. Therefore, in the case of chronic and stable scleroderma, short-term rehabilitation during hospitalization for chest physical therapy possibly shows clinical benefits by improving both pulmonary function and physical performance.

Risk Stratification for Lung Cancer Surgery

STUDY OBJECTIVES

Current surgical strategies for lung cancer are directed toward the following two distinct targets: the increased prevalence of early-stage lung cancer; and locally advanced lung cancer treated with induction therapy (IT). To establish the risk stratification for operative morbidity from this viewpoint, we evaluated the impact of IT and/or an extended surgical procedure on operative results.

DESIGN

Retrospective study.

SETTING

A 674-bed teaching hospital.

PATIENTS AND METHODS

The morbidity and mortality of 758 consecutive patients who underwent surgery for the treatment of non-small cell lung cancer were analyzed. There were 666 patients who underwent surgery alone (S group; 560 standard lobectomies and 106 extended resections) and 92 patients who received IT (IT group; 35 standard lobectomies and 57 extended resections). Comparisons between the groups were performed using unpaired t tests or chi(2) tests. Univariate and multivariate logistic regression analyses were used to determine the risk factors for operative morbidity and mortality.

RESULTS

IT and extended surgery were strong independent factors for predicting postoperative morbidity (p < 0.0001). Significant differences were observed for pathologic stage (p < 0.0001), preoperative hemoglobin and Dlco levels (p < 0.001), the ratio of extended resection (p < 0.0001), and operation time and intraoperative bleeding (p < 0.001) between the S and IT groups. The overall morbidity and mortality rates were 16.8% and 0.9%, respectively, in the S group, and 55.4% and 5.4%, respectively, in the IT group (p < 0.01). The overall morbidity and mortality rates were 63.2% and 7.0%, respectively, for extended resection after IT, and 12.8% and 0.3%, respectively, for those who underwent a standard resection without IT.

CONCLUSIONS

The morbidity and mortality of lung resection are both significantly increased after IT, and the patients with the greatest risk are those who have undergone IT and extended resection. The impact of IT on risk stratification should be emphasized in perioperative care.

Nasal CPAP therapy: effects of different CPAP levels on pressure transmission into the trachea and pulmonary oxygen transfer

BACKGROUND

Nasal continuous positive airway pressure (nCPAP) is considered useful for prophylaxis and treatment of respiratory complications following major thoracic surgery. It is unknown, however, which CPAP levels are required to avoid alveolar derecruitment and to consistently improve pulmonary oxygen transfer in patients following thoracotomy. We therefore studied the effects of different nCPAP levels on pressure transmission into the trachea as well as on pulmonary oxygen transfer.

METHODS

In 10 consecutive patients after cardiac or thoracic vascular surgery, following extubation in the ICU, nCPAP was generated by means of a high-flow gas source and applied randomly at levels of 5 or 10 cm H2O. Airway pressure was recorded continuously in the nasal mask and the trachea. The PaO2/FiO2ratio was calculated from the tracheal oxygen concentration, and PaO2 was determined while breathing at an ambient and elevated airway pressure. Haemodynamic variables (heart rate, arterial blood pressure, central venous pressure) were also recorded.

RESULTS

Mean pressures in the nasal mask were 5.4+/-0.1 and 9.7+/-0.3 cm H2O. Corresponding tracheal pressures were 2.8+/-1.0 vs. 7.2+/-1.1 cm H2O (P=0.007). With higher mask pressure, the fraction of pressure transferred from the nasal mask into the trachea was larger (0.75+/-0.03 vs. 0.52+/-0.05; P=0.04), and tracheal pressures remained positive during the entire respiratory cycle in all patients. In contrast, with 5.4 cm H20, negative pressure changes during inspiration occurred in five out of 10 patients. The PaO2/FiO2 ratio increased from 183+/-53 (ambient pressure) to 199+/-74 (nCPAP 5.4 cm H2O; P=0.25) and to 333+/-54 (nCPAP 9.7 cm H2O; P=0.003). Nasal CPAP did not alter hemodynamics.

CONCLUSION

Nasal CPAP is an effective non-invasive means of increasing tracheal and thus intrathoracic pressure without adverse hemodynamic effects. Only mask pressures of 9-10 cm H2O were sufficient to consistently improve pulmonary oxygen transfer in patients following thoracotomy.