Titration of High Frequency Percussive Ventilation by means of real-time monitoring of the viscoelastic respiratory system properties and endotracheal tubes pressure drop.

2012/2013The use of High Frequency Percussive Ventilation (HFPV) is still debated although this type of non-conventional ventilation has proven effective and safe in patients with acute respiratory failure. In the clinical practice, HFPV is not an intuitive ventilatory modality and the absence of real-time delivered volume monitoring produces disaffection among the physicians. Avoiding the "volutrauma" is the cornerstone of the "protective ventilation strategy", which assumes a constant monitoring of inspiratory volume delivered to the patient. Currently the system capable of delivering HFPV is the VDR-4® (Volumetric Diffusive Respirator), which provides only analog airway pressure waveform and digital output of peak and the mean airway pressure. The latter is involved in the determination of oxygenation and hemodynamics, irrespective of the mode of ventilation. At the present time, the mean airway pressure, together with gas exchange analysis, are the only parameters that indirectly guide the physician in assessing the clinical effectiveness of HFPV. Till now, flow, volume and pressure curves generated by HFPV have never been studied in relation to the specific patients respiratory mechanics. The real-time examination of these parameters could allow the physicians to analyze and understand elements of respiratory system mechanics as compliance (Crs), resistance (Rrs), inertance (Irs) and of patient-ventilator interaction. The mechanical effects are complex and result from interactions between ventilator settings and patient’s respiratory system impedance. The aim of this doctoral thesis was to acquire and study volume and respiratory parameters during HFPV in order to explain this complex patients-machine interaction and transfer the results in clinical practice.XXVI Ciclo195

Acute myocardial infarction in non-cardiac critically ill patients: a clinical-pathological study.

Background: in patients admitted to the Intensive Care Unit (ICU) for non cardiac disease, the diagnosis of acute coronary syndromes can be challenging. The aim of the study was to define the rate of discrepancies concerning the diagnosis of acute myocardial infarction and to evaluate the presence of risk factors that could be helpful in identifying patients at higher risk of missed diagnosis. Methods: we compared clinical and autopsy records of 600 critically ill patients who died in our ICU in a 10-years period. We identified patients in whom acute myocardial infarction was reported as the cause of death on the clinical records or was discovered only at post-mortem examination. These subjects were subsequently divided into two Groups: patients in Group 1 underwent diagnostic evaluation for acute myocardial infarction whereas those in Group 2 were not investigated for. Results: In Group 1, a definite clinical diagnosis was reached in 11 patients (14,7%) but remained undetermined in 37 patients (48%). The diagnosis was totally missed in 8 patients in Group 1 (10,6%) and in 20 patients of Group 2 (26,6%). The diagnostic discrepancy was higher in septic patients, in whom the correct diagnosis of acute myocardial infarction was established at a rate lower than 50% in respect to non-septic patients. Conclusions: Our experience strengthens the role of post-mortem examination as a source of feed-back of the overall diagnostic and therapeutic approach especially in septic patients, where the diagnostic error is more frequent

Postoperative analgesia after pulmonary resection with a focus on video-assisted thoracoscopic surgery

Video-assisted thoracoscopic surgery is a widespread technique that has been linked to improved postoperative respiratory function, reduced hospital length of stay and a higher level of tolerability for the patients. Acute postoperative pain is of considerable significance, and the late development of neuropathic pain syndrome is also an issue. As anaesthesiologists, we have investigated the available evidence to optimize postoperative pain management. An opioid-sparing multimodal approach is highly recommended. Loco-regional techniques such as the thoracic epidural and peripheral blocks can be performed. Several adjuvants have been employed with varying degrees of success both intravenously and in combination with local anesthetics. Opioids with different pharmacodynamic and pharmacokinetic profiles can be used, either through continuous infusion or on demand. Non-opioid analgesics are also beneficial. Finally, perioperative gabapentinoids may be implemented to prevent the onset of chronic neuropathic pain

"Shoulder pain and limitation of motion in a young girl: think different"

Background Primary Synovial Chondromatosis (PSC) is a rare benign tumor of the synovial membrane in which cartilage metaplasia produces calcific loose bodies within the articular space. Only a few cases are reported in the pediatric population and its etiology remains unknown. This condition typically affects large weight-bearing joints with pain, swelling and decrease range of motion. Due to its slow progressions, delayed diagnosis is frequent and differential diagnosis should consider other chronic arthritis and malignancies. While arthroscopic removal of loose bodies is the current treatment up to now, the association of partial or complete synovectomy is debated. Case presentation We report about a 14-year-old girl with a long-lasting right shoulder pain, especially during movements or exercise, localized tenderness and hypotonia of the glenohumeral joint. No previous trauma was mentioned. Blood exams, Mantoux test and plain radiography of the right shoulder were unremarkable. Ultrasound imaging revealed echogenic and calcified bodies stretching the glenohumeral joint and dislocating the long head of biceps tendon. Magnetic resonance showed a "rice-grain" pattern of the right shoulder. From an arthroscopic surgery, multiple loose white bodies were removed within the synovial membrane, and synovial chondromatosis was confirmed by histological analysis. At one month follow up visit, the patient completely recovered without pain. Conclusion Synovial chondromatosis is a very uncommon cause of mono articular pain in children, especially when it affects shoulder. Pediatricians should keep in mind this condition to avoid delayed diagnosis and treatment, even in consideration of the low risk of malignant transformation. Through this case, we would highlight common diagnostic pitfalls and treatment of synovial chondromatosis

High-Flow Nasal Interface Improves Oxygenation in Patients Undergoing Bronchoscopy

During bronchoscopy hypoxemia is commonly found and oxygen supply can be delivered by interfaces fed with high gas flows. Recently, the high-flow nasal cannula (HFNC) has been introduced for oxygen therapy in adults, but they have not been used so far during bronchoscopy in adults. Forty-five patients were randomly assigned to 3 groups receiving oxygen: 40 L/min through a Venturi mask (V40, N = 15), nasal cannula (N40, N = 15), and 60 L/min through a nasal cannula (N60, N = 15) during bronchoscopy. Gas exchange and circulatory variables were sampled before (FiO2 = 0.21), at the end of bronchoscopy (FiO2 = 0.5), and thereafter (V40, FiO2 = 0.35). In 8 healthy volunteers oxygen was randomly delivered according to V40, N40, and N60 settings, and airway pressure was measured. At the end of bronchoscopy, N60 presented higher PaO2, PaO2/FiO2, and SpO2 than V40 and N40 that did not differ between them. In the volunteers (N60) median airway pressure amounted to 3.6 cmH2O. Under a flow rate of 40 L/min both the Venturi mask and HFNC behaved similarly, but nasal cannula associated with a 60 L/min flow produced the better results, thus indicating its use in mild respiratory dysfunctions

Early Short-Term Application of High-Frequency Percussive Ventilation Improves Gas Exchange in Hypoxemic Patients

Background: Hypoxemia in acute lung injury/acute respiratory distress syndrome (ALI/ARDS) patients represents a common finding in the intensive care unit (ICU) and frequently does not respond to standard ventilatory techniques. Objective: To study whether the early short-term application of high-frequency percussive ventilation (HFPV) can improve gas exchange in hypoxemic patients with ALI/ARDS or many other conditions in comparison to conventional ventilation (CV) using the same mean airway pressure (Paw), representing the main determinant of oxygenation and hemodynamics, irrespective of the mode of ventilation. Methods: Thirty-five patients not responding to CV were studied. During the first 12 h after admission to the ICU the patients underwent CV. Thereafter HFPV was applied for 12 h with Paw kept constant. They were then returned to CV. Gas exchange was measured at: 12 h after admission, every 4 h during the HFPV trial, 1 h after the end of HFPV, and 12 h after HFPV. Thirty-five matched patients ventilated with CV served as the control group (CTRL). Results: Pao2/Fio2 and the arterial alveolar ratio (a/A Po2) increased during HFPV treatment and a Pao2/Fio2 steady state was reached during the last 12 h of CV, whereas both did not change in CTRL. Paco2 decreased during the first 4 h of HFPV, but thereafter it remained unaltered; Paco2 did not vary in CTRL. Respiratory system compliance increased after HFPV. Conclusions: HFPV improved gas exchange in patients who did not respond to conventional treatment. This improvement remained unaltered until 12 h after the end of HFPV

Neuronal desertification after a direct lightning strike: a case report

Background: Lightning strike is a rare but dramatic cause of injury. Patients admitted to intensive care units (ICUs) with lightning strike frequently have a high mortality and significant long-term morbidity related to a direct brain injury or induced cardiac arrest (CA). Case presentation: A 50-year-old Caucasian man was admitted to our hospital after being struck by lightning resulting in immediate CA. Spontaneous circulation was initially restored, and the man was admitted to the ICU, but ultimately died while in hospital due to neurological injury. The computer tomography scan revealed a massive loss of grey-white matter differentiation at the fronto-temporal lobes bilaterally. Somatosensory-evoked potentials demonstrated bilateral absence of the cortical somatosensory N20-potential, and the electroencephalogram recorded minimal cerebral electrical activity. The patient died on day 10 and a post-mortem study revealed a widespread loss of neurons. Conclusion: This case study illustrates severe brain injury caused by a direct lighting strike, with the patient presenting an extraordinary microscopic pattern of neuronal desertification

Topical Steroids in Rhinosinusitis and Intraoperative Bleeding: More Harm Than Good?

The aim of this study was to assess whether the chronic preoperative administration of intranasal corticosteroids (INCs) in chronic rhinosinusitis with/without nasal polyposis (CRSwNP/CRSsNP, respectively) could significantly influence bleeding during functional endoscopic sinus surgery (FESS). We prospectively enrolled 109 patients (56 CRSwNP and 53 CRSsNP) candidate for FESS who underwent clinical evaluation and anamnestic data collection. They were allocated to 2 groups depending on whether or not they were chronic INC users, as declared at their first medical evaluation: chronic "INC users" represented the treated group, while "INC nonusers" formed the control group. Lund-Mackay and American Society of Anesthesiology (ASA) scores, blood loss expressed both in milliliters and using the Boezaart scale, operation time in minutes, pre- and postoperative 22-item Sino Nasal Outcome Scores (SNOT-22) were collected. Each sample underwent histopathological evaluation. The results showed that anamnestic information, Lund-Mackay, and SNOT-22 scores were similar between the 2 groups ( P > .05). The average blood loss expressed in milliliters and operative time were slightly, but not significantly, higher in the INC user group, while the Boezaart scores proved significantly higher in the INC users ( P = .038). No differences emerged between CRSwNP and CRSsNP within each group in terms of bleeding. The pathologist described common features in the majority (78%) of INC group samples: ectatic venules embedded in a fibrous stroma and hypertrophy of the arterial muscular layer. In our experience, despite the presence of NP, chronic preoperative administration of INCs was associated with increased intraoperative bleeding according the Boezaart scale although objective recordings of blood loss were not statistically different between the INC users and nonusers

Patient-ventilator asynchronies during mechanical ventilation: current knowledge and research priorities

Background: Mechanical ventilation is common in critically ill patients. This life-saving treatment can cause complications and is also associated with long-term sequelae. Patient-ventilator asynchronies are frequent but underdiagnosed, and they have been associated with worse outcomes.Main body: Asynchronies occur when ventilator assistance does not match the patient's demand. Ventilatory overassistance or underassistance translates to different types of asynchronies with different effects on patients. Underassistance can result in an excessive load on respiratory muscles, air hunger, or lung injury due to excessive tidal volumes. Overassistance can result in lower patient inspiratory drive and can lead to reverse triggering, which can also worsen lung injury. Identifying the type of asynchrony and its causes is crucial for effective treatment.Mechanical ventilation and asynchronies can affect hemodynamics. An increase in intrathoracic pressure during ventilation modifies ventricular preload and afterload of ventricles, thereby affecting cardiac output and hemodynamic status. Ineffective efforts can decrease intrathoracic pressure, but double cycling can increase it. Thus, asynchronies can lower the predictive accuracy of some hemodynamic parameters of fluid responsiveness.New research is also exploring the psychological effects of asynchronies. Anxiety and depression are common in survivors of critical illness long after discharge. Patients on mechanical ventilation feel anxiety, fear, agony, and insecurity, which can worsen in the presence of asynchronies. Asynchronies have been associated with worse overall prognosis, but the direct causal relation between poor patient-ventilator interaction and worse outcomes has yet to be clearly demonstrated.Critical care patients generate huge volumes of data that are vastly underexploited. New monitoring systems can analyze waveforms together with other inputs, helping us to detect, analyze, and even predict asynchronies. Big data approaches promise to help us understand asynchronies better and improve their diagnosis and management.Conclusions: Although our understanding of asynchronies has increased in recent years, many questions remain to be answered. Evolving concepts in asynchronies, lung crosstalk with other organs, and the difficulties of data management make more efforts necessary in this field