Validation of the Arabic Severe Respiratory Insufficiency Questionnaire.

BACKGROUND/OBJECTIVES: Assessment of Health-Related Quality of Life (HRQL) in patients with chronic respiratory insufficiency requiring Home Mechanical Ventilation (HMV) requires a valid measurement tool. The Severe Respiratory Insufficiency (SRI) questionnaire, originally developed in German, has been translated into different languages and tested in different contexts, but has so far not been in use in Arabic-speaking populations. The objective of this study is to validate the Arabic version of the SRI questionnaire in a sample of Arabic-speaking patients from Lebanon. METHODS: Following forward/backward translations, the finalized Arabic version was administered to 149 patients (53 males-96 females, age 69.80 ± 10 years) receiving HMV. Patients were recruited from outpatient clinics and visited at home. The Arabic SRI and the 36-Item Short-Form Health Survey (SF-36) were administered, in addition to questions on sociodemographics and medical history. Exploratory Factor Analysis (EFA) was used to explore dimensionality; internal consistency reliability of the unidimensional scale and its subscales was assessed using Cronbach's alpha. External nomological validity was examined by assessing the correlation between the SRI and SF-36 scores. RESULTS: The 49-item Arabic SRI scale showed a high internal consistency reliability (Cronbach alpha for the total scale was 0.897 and ranged between 0.73 and 0.87 for all subscales). Correlations between the SF-36-Mental Health Component MHC and SF-36-Physical Health Component with SRI-Summary Scale were 0.57 and 0.66, respectively, with higher correlations observed between the SF-36 and specific sub-scales such as the Physical Functioning and the Social Functioning subscales [r = 0.81 and r = 0.74 (P < 0.01), respectively]. CONCLUSION AND RECOMMENDATIONS: The Arabic SRI is a reliable and valid tool for assessing HRQL in patients with chronic respiratory insufficiency receiving home mechanical ventilation.

PATIENT-VENTILATION ASYNCHRONY CAUSING NEGATIVE PRESSURE PULMONARY EDEMA IN AN INTUBATED OBESE PATIENT.

Negative pressure pulmonary edema is a potentially life-threatening condition that may occur when a large negative intrathoracic pressure is generated against a 'physically' obstructed upper airway during emergence from anesthesia. We report a 35 year old male patient who is morbidly obese and undergoing laparoscopic gastric bypass who developed negative pressure pulmonary edema without any evidence of a 'physical' upper airway obstruction. In our patient, the negative pressure pulmonary edema occurred after complete reversal of neuromuscular blockade and during manual positive pressure ventilation with the endotracheal tube still in place and in the presence of an oral airway. Since the patient was still intubated and had an airway in place with no possibility for physical obstruction, we speculate that the occurrence of the negative pressure pulmonary edema was mainly due to a 'functional' obstruction secondary to the severe patient-ventilation asynchrony that ensued upon reversal of the neuromuscular blockade.

Effect of heliox- and air-driven nebulized bronchodilator therapy on lung function in patients with asthma.

BACKGROUND: This study compares the effect of heliox-driven to that of air-driven bronchodilator therapy on the pulmonary function test (PFT) in patients with different levels of asthma severity. METHODS: One-hundred thirty-two participants were included in the study. Participants underwent spirometry twice with bronchodilator testing on two consecutive days. Air-driven nebulization was used one day and heliox-driven nebulization the other day in random order crossover design. After a baseline PFT, each participant received 2.5 mg of albuterol sulfate nebulized with the randomized driving gas. Post bronchodilator PFT was repeated after 30 min. The next day, the exact same protocol was repeated, except that the other driving gas was used to nebulize the drug. Participants were subgrouped and analyzed according to their baseline FEV(1) on day 1: Group I, FEV(1) ≥80 %; Group II, 80 % > FEV(1) > 50 %; Group III, FEV(1) ≤50 %. The proportion of participants with greater than 12 % and 200-mL increases from their baseline FEV(1) and the changes from baseline in PFT variables were compared between heliox-driven versus air-driven bronchodilation therapy. RESULTS: The proportion of participants with >12 % and 200-mL increases from their baseline FEV(1) with air- or heliox-driven bronchodilation was not different with respect to the proportion of participants with baseline FEV(1) ≥80 % (20 vs. 18 %, respectively) and 80 % > FEV(1) > 50 % (36 vs. 43 %, respectively), but it was significantly greater with heliox-driven bronchodilation in participants with FEV(1) ≤50 % (43 vs. 73 %, respectively; p = 0.01). Changes from baseline FVC, FEV(1), FEV(1)/FVC, FEF(25-75) %, FEF(max), FEF(25) %, FEF(50) %, and FEF(75) % were significantly larger with heliox-driven versus air-driven bronchodilation in participants with baseline FEV(1) ≤50 %. CONCLUSION: Improvements in PFT variables are more frequent and profound with heliox-driven compared to air-driven bronchodilator therapy only in asthmatic patients with baseline FEV(1) ≤50 %.

Ratio of oxygen saturation index for predicting high-flow nasal cannula outcomes in emergency department for COVID-19 patients with severe hypoxemia: A retrospective study.

OBJECTIVES: High-flow nasal cannula (HFNC) oxygen therapy has been used as an initial ventilatory support for coronavirus disease 2019 (COVID-19) patients with mixed levels of acute hypoxemic respiratory failure (AHRF). However, the effectiveness of HFNC when used as initial ventilatory support in COVID-19 patients with severe AHRF exclusively is not well documented. Ratio of oxygen saturation (ROX) index (ROX = [SpO2/fraction of inspired oxygen]/respiratory rate) was shown to predict the outcome of HFNC in intensive care unit patients. Our study aimed to evaluate the utility of the ROX index for predicting HFNC therapy success/failure in COVID-19 patients with severe AHRF when HFNC is used as the first line of ventilatory support. METHODS: Retrospective study in 67 COVID-19 patients with severe AHRF receiving HFNC in the emergency department at a tertiary care academic medical center. ROX index was determined at 0, 2, 6, 12, and 24 h of HFNC onset. The need to escalate to noninvasive or invasive ventilatory support was documented. The receiver operating characteristic curves were performed and areas under the curves (AUCs) were calculated to evaluate the accuracy of ROX index for differentiating between patients who will succeed or fail HFNC therapy. RESULTS: HFNC therapy was successful in 19 patients (28.1%) and failed in 48 patients (71.6%). ROX index after 6 h of HFNC initiation had the best predictive capacity for the outcome of HFNC therapy (AUC = 0.78). ROX index >4.4 at 6 h of HFNC onset was significantly associated with HFNC success/failure. CONCLUSION: ROX index at 6 h after initiating HFNC therapy in COVID-19 patients with severe AHRF has a good predictive capacity for HFNC success/failure.

Effect of Ventilator Settings on Mechanical Power During Simulated Mechanical Ventilation of Patients With ARDS.

BACKGROUND: In recent years, mechanical power (MP) has emerged as an important concept that can significantly impact outcomes from mechanical ventilation. Several individual components of ventilatory support such as tidal volume (VT), breathing frequency, and PEEP have been shown to contribute to the extent of MP delivered from a mechanical ventilator to patients in respiratory distress/failure. The aim of this study was to identify which common individual setting of mechanical ventilation is more efficient in maintaining safe and protective levels of MP using different modes of ventilation in simulated subjects with ARDS. METHODS: We used an interactive mathematical model of ventilator output during volume control ventilation (VCV) with either constant inspiratory flow (VCV-CF) or descending ramp inspiratory flow, as well as pressure control ventilation (PCV). MP values were determined for simulated subjects with mild, moderate, and severe ARDS; and whenever MP > 17 J/min, VT, breathing frequency, or PEEP was manipulated independently to bring back MP to ≤ 17 J/min. Finally, the optimum VT-breathing frequency combinations for MP = 17 J/min were determined with all 3 modes of ventilation. RESULTS: VCV-CF always resulted in the lowest MPs while PCV resulted in highest MPs. Reductions in VT were the most efficient for maintaining safer and protective MP. At targeted MPs of 17 J/min and maximized minute ventilation, the optimum VT-breathing frequency combinations were 250-350 mL for VT and 32-35 breaths/min for breathing frequency in mild ARDS, 200-350 mL for VT and 34-40 breaths/min for breathing frequency in moderate ARDS, and 200-300 mL for VT and 37-45 breaths/min for breathing frequency for severe ARDS. CONCLUSIONS: VCV-CF resulted in the lowest MP. VT was the most efficient for maintaining safe and protective MP in a mathematical simulation of subjects with ARDS. In the context of maintaining low and safe MPs, ventilatory strategies with lower-than-normal VT and higher-than-normal breathing frequency will need to be implemented in patients with ARDS.

Subpleural block is less effective than thoracic epidural analgesia for post-thoracotomy pain: a randomised controlled study.

CONTEXT: Thoracic epidural and paravertebral blocks provide adequate analgesia for postoperative thoracotomy pain. Both procedures are usually performed percutaneously with considerable failure rates. A subpleural catheter placed in the space posterior to the parietal pleura and alongside the paravertebral area may provide superior postoperative pain relief. OBJECTIVE: To compare subpleural analgesia with thoracic epidural analgesia in patients undergoing thoracotomy. DESIGN: Randomised, double-blind study. SETTING: A tertiary care University Medical Centre between 26 June 2008 and 21 March 2011. PATIENTS: Forty-two patients scheduled for elective posterolateral thoracotomy. Patients with American Society of Anesthesiologists physical status ≥4, with a previous history of thoracotomy, on chronic pain medications or with a contraindication to receiving local anaesthetics or thoracic epidural block were excluded from the study. INTERVENTIONS: Patients were randomised to receive either subpleural analgesia or thoracic epidural analgesia for 24-h post-thoracotomy pain control. MAIN OUTCOME MEASURES: A visual analogue scale was used to assess pain at rest and on coughing during the first 24 h postoperatively and the incidence of hypotension was recorded. RESULTS: Patients who received subpleural analgesia had higher visual analogue scores at rest and on coughing than those who received thoracic epidural analgesia. Seven patients who started with subpleural analgesia were treated with thoracic epidural analgesia at a mean (SD) of 3.9 (4.8) h. The remaining 14 patients had a median (IQR [range]) visual analogue score of 5 cm (4-5 [3-6]) at rest and were maintained on subpleural analgesia until the end of the study. The visual analogue score at rest was <7 cm in all 21 patients who received thoracic epidural analgesia and none was switched to subpleural analgesia during the study. None of the patients in the subpleural analgesia group experienced hypotension compared with five of the 21 patients in the thoracic epidural analgesia group (P=0.047). CONCLUSION: Thoracic epidural analgesia is superior to subpleural analgesia in relieving post-thoracotomy pain.

Dexamethasone with either granisetron or ondansetron for postoperative nausea and vomiting in laparoscopic surgery.

In a prospective randomized double-blind study, we compared the effectiveness of dexamethasone 8 mg with either granisetron 1 mg or ondansetron 4 mg in the prevention of postoperative nausea and vomiting in patients undergoing laparoscopic surgery. Hundred ASA I and II patients scheduled for laparoscopic surgery were enrolled in the study and 84 patients completed it. Following induction of anesthesia, group I (n=42) received granisetron 1 mg and dexamethasone 8 mg, group II (n=42) received ondansetron 4 mg and dexamethasone 8 mg. Nausea and vomiting episodes, pain scores as well as side effects were recorded during the first hour and subsequently during the first 6 and 24 hours postoperatively. Satisfaction scores were obtained at discharge. There was no statistically significant difference between the 2 groups during the 1st 24 hours following surgery in regards to pain scores, satisfaction and side effects manifestations. At 0-1 hour interval, 100% of patients in group I and 97.6% in group II had no vomiting. Total response (no moderate or severe nausea and no rescue antiemetics) was 83.3% in group I and 80.95% in group II, and metoclopramide was used in 7.1% of patients in both groups. At 1-6 hours interval, 97.6% of patients in group I and 100% in group II had no vomiting. Total response was 92.8% in group I and 90.9% in group II, and metoclopramide was used in 4.76% of patients in group I and 2.38% in group II. At 6-24 hours no vomiting occurred in 97.6% of patients in group I and 100% in group II. Total response was 95.2% in both groups, and metoclopramide was used in 2.38% of patients in both groups. In conclusion, the combination of dexamethasone 8 mg with either granisetron 1 mg or ondansetron 4 mg following induction of anesthesia in patients undergoing laparoscopic surgery showed no statistically significant difference in antiemetic efficacy with minimal side effects and excellent patient satisfaction.

Comparison of the Oxygenation Factor and the Oxygenation Ratio in Subjects With ARDS.

BACKGROUND: The oxygenation ratio (ie, [Formula: see text]/[Formula: see text]) remains the most commonly used index for assessing oxygenation and disease severity in patients with acute ARDS. However, the oxygenation ratio does not account for mechanical ventilation settings. We hypothesized that the oxygenation factor (ie, oxygenation ratio/mean airway pressure) is superior to the oxygenation ratio in reflecting oxygenation in patients with ARDS and results in a different classification of ARDS severity. METHODS: In 150 subjects with ARDS (50 severe, 50 moderate, and 50 mild), arterial blood gas, mean airway pressure, static lung compliance, driving pressure, and mechanical power were obtained. The oxygenation ratio and the oxygenation factor were then calculated. Receiver operating characteristic curves were constructed for oxygenation ratio and oxygenation factor at lung compliance > 40 mL/cm H2O, driving pressure < 15 cm H2O, and mechanical power < 17 J/min, thresholds that are known to predict survival in patients with ARDS. Subjects were reclassified for ARDS severity on the basis of the oxygenation factor and compared to classification on the basis of the oxygenation ratio. RESULTS: Areas under the receiver operating characteristic curves for the oxygenation factor were significantly higher than for the oxygenation ratio. Reclassification of ARDS severity using the oxygenation factor did not affect subjects classified as having severe ARDS per the oxygenation ratio. However, 52% of subjects with moderate ARDS per the oxygenation ratio criteria were reclassified as either severe (25 subjects) or mild ARDS (1 subject) on the basis of oxygenation factor criteria. Also, 54% of subjects with mild ARDS per the oxygenation ratio criteria were reclassified as severe (4 subjects), moderate (21 subjects), or non-ARDS (2 subjects) on the basis of oxygenation factor criteria. CONCLUSIONS: The oxygenation factor was a superior ARDS oxygenation index compared to the oxygenation ratio and should be considered as a substitute criteria for classification of the severity of ARDS. (ClinicalTrials.gov registration NCT03946189.).

Continuous Positive Airway Pressure (CPAP) in Non-Apneic Asthma: A Clinical Review of Current Evidence.

The use of continuous positive airway pressure (CPAP) in asthma has been a point of debate over the past several years. Various studies, including those on animals and humans have attempted to understand the role and pathophysiology of CPAP in patients with either well controlled or poorly controlled asthma. The aim of this manuscript is to review the currently available literature on the physiologic and clinical effects of CPAP in animal models of asthma and on humans with stable asthma.

Prophylactic amiodarone versus lidocaine for prevention of reperfusion ventricular fibrillation after release of aortic cross-clamp.

BACKGROUND AND OBJECTIVE: Ventricular fibrillation is common after aortic cross-clamp release in patients undergoing open-heart surgeries. The aim of the study was to evaluate the efficacy of the prophylactic administration of 150 mg amiodarone by way of the pump 2 min before release of aortic cross-clamp in preventing ventricular fibrillation. METHODS: The present study is a prospective, randomized, controlled and blinded study performed at a teaching university hospital where 120 patients undergoing coronary bypass graft surgery were randomly assigned to three groups. Each group received either 150 mg of amiodarone or 100 mg lidocaine or isotonic saline by way of pump 2 min before release of the aortic cross-clamp. The frequency of occurrence of ventricular fibrillation and the subsequent required defibrillation counter shocks were determined in all groups. RESULTS: The frequency of occurrence of ventricular fibrillation was significantly higher in both the amiodarone (48%) and the control group (45%) as compared with the lidocaine group (20%) with no statistically significant difference between the amiodarone and the control groups. Furthermore, when ventricular fibrillation occurred, the percentage of patients requiring defibrillation counter shocks was significantly higher in both the amiodarone (58%) and control (61%) groups as compared with the lidocaine group (13%) with no difference between the amiodarone and the control groups, despite a significant decrease in the defibrillation counter shocks energy requirements in the amiodarone group. CONCLUSION: The present study showed no difference between amiodarone (150 mg) and placebo in preventing ventricular fibrillation after release of aortic cross-clamp. In addition, the use of lidocaine was able to reduce the incidence of ventricular fibrillation as compared with both amiodarone and placebo.

Effect of pressure support ventilation and positive end expiratory pressure on the rapid shallow breathing index in intensive care unit patients.

OBJECTIVE: We compared rapid shallow breathing index (RSBI) values under various ventilatory support settings prior to extubation. DESIGN AND SETTING: Prospective study in the intensive care unit at a university hospital. PATIENTS: Thirty six patients ready for extubation. INTERVENTIONS: Patients were enrolled when receiving pressure support ventilation (PSV) of 5 cmH2O, PEEP of 5 cmH2O, and FIO2 of 40% (PS). Subsequently each patient received a trial of PSV of 0 cmH2O, PEEP of 5 cmH2O, and FIO2 of 40% (CPAP), a trial of PSV of 0 cmH2O, PEEP of 5 cmH2O and FIO2 of 21% (CPAP-R/A), and a 1-minute spontaneously breathing room air trial off the ventilator (T-piece). Trials were carried out in random order. MEASUREMENTS AND RESULTS: Respiratory frequency (f) and tidal volume (VT) were measured during PS, CPAP, CPAP-R/A, and T-piece in all patients. RSBI (f/VT) was determined for each patient under all experimental conditions, and the average RSBI was compared during PS, CPAP, CPAP-R/A, and T-piece. RSBI was significantly smaller during PS (46+/-8 bpm/l), CPAP (63+/-13 bpm/l) and CPAP-R/A (67+/-14 bpm/l) vs. T-piece (100+/-23 bpm/l). There was no significant difference in RSBI between CPAP and CPAP-R/A. RSBI during CPAP and CPAP-R/A were significantly smaller than RSBI during T-piece. In all patients RSBI values were less than 105 bpm/l during PS, CPAP, and CPAP-R/A. However, during T-piece the RSBI increased to greater than 105bpm/l in 13 of 36 patients. CONCLUSIONS: In the same patient the use of PSV and/or PEEP as low as 5 cmH2O can influence the RSBI. In contrast, changes in FIO2 may have no effect on the RSBI.

Clinical review: liberation from mechanical ventilation.

Mechanical ventilation is the defining event of intensive care unit (ICU) management. Although it is a life saving intervention in patients with acute respiratory failure and other disease entities, a major goal of critical care clinicians should be to liberate patients from mechanical ventilation as early as possible to avoid the multitude of complications and risks associated with prolonged unnecessary mechanical ventilation, including ventilator induced lung injury, ventilator associated pneumonia, increased length of ICU and hospital stay, and increased cost of care delivery. This review highlights the recent developments in assessing and testing for readiness of liberation from mechanical ventilation, the etiology of weaning failure, the value of weaning protocols, and a simple practical approach for liberation from mechanical ventilation.

Use of heparinized versus non-heparinized syringes for measurements of the pleural fluid pH.

BACKGROUND: Pleural fluid (PF) pH measurement is important for establishing a diagnosis and for guiding clinical management. The current standard practice is to collect PF samples for pH measurement in heparinized syringes at room temperature and to instantaneously process these samples. OBJECTIVE: The purpose of this study is to investigate the effect of collecting PF in heparinized versus non-heparinized syringes at room temperature on PF pH measurements when processed at various time intervals. METHODS: From 50 consecutive thoracenteses, 1 ml of PF was collected anaerobically in each of six 3-ml syringes. Only three syringes were coated with heparin. The samples were processed for PF pH measurements at time 0 (T(0)) and 1 h (T(1)) and 2 h (T(2)) after collection. All specimens were preserved at room temperature, until the measurements were carried out in duplicates by a calibrated blood gas analyzer. RESULTS: PF pH values were significantly lower with heparinized versus non-heparinized syringes at all time intervals (T(0): pH heparinized = 7.378 +/- 0.107 vs. pH non-heparinized = 7.390 +/- 0.108; T(1): pH heparinized = 7.378 +/- 0.115 vs. pH non-heparinized = 7.389 +/- 0.111; T(2): pH heparinized = 7.367 +/- 0.105 vs. pH non-heparinized = 7.389 +/- 0.121). In the heparinized syringes, there was a significant decrease in PF pH values at T(2) versus T(0) and T(1). There were no significant changes in PF pH values over time in the non-heparinized syringes. CONCLUSIONS: For serial PF pH measurements, the same type of syringes (either heparinized or non-heparinized) should be consistently used. With heparinized syringes, processing of PF pH measurements should be performed within 1 h after collection.

A diagnostic software tool for determination of complexity in respiratory pattern parameters.

The development and validation of a software that is user friendly and flexible in determining approximate entropy and reflecting complexity in respiratory pattern parameters are presented. The report includes the theory and computational methods for approximate entropy as well as the system description and software architecture. Results for a simulated periodic and regular respiratory pattern as well as for an irregular and complex breathing pattern obtained from a patient receiving mechanical ventilation in the intensive care unit are provided. By providing easy and rapid determination of the approximate entropy, the software enables health care professionals to understand how specific mechanical ventilation settings influence the respiratory pattern for patients receiving mechanical ventilation in the intensive care unit and ultimately identify the reversibility of respiratory diseases and weaning and liberation from mechanical ventilation.

[Nondepolarizing muscle relaxant improves direct laryngoscopy view with no effect on face mask ventilation]. / Relaxantes musculares não despolarizantes melhoram a visibilidade em laringoscopia direta sem efeito sobre a ventilação via máscara facial.

BACKGROUND: Difficult or impossible face mask ventilation complicated with difficult tracheal intubation during anesthesia induction occurs in 0.4% of adult anesthesia cases, possibly leading to life-threatening complications. Because of such catastrophes, muscle relaxants have been recommended to be administered after confirming adequate face mask ventilation without a solid scientific validation of this principal. METHODS: In this observational study, the ease of ventilation and the scores of direct laryngoscopy views before and after administration of cisatracurium were assessed in ninety young healthy adults, without anesthetic risks and without foreseen difficult intubation and who were scheduled for general elective surgeries. RESULTS: Before muscle relaxation, 43 patients (48%) were Cormack Grade I, while the remaining 47 patients (52%) were either Cormack Grade II (28 patients, 31%) or Cormack Grade II (19 patients, 21%). Following muscle relaxation with cisatracurium, the number of patients with Cormack Grade I significantly increased from 43 patients (48%) to 65 patients (72%) (p=0.0013). Only 1 patient out of 19 patients (5%) improved his Cormack grade from Grade III to Grade I while 16 out 19 patients (84%) improved their Cormack grade from Grade III to Grade II after the use of cisatracurium. The quality of face mask ventilation did not differ with and without muscle relaxants in all patients. CONCLUSION: The use of cisatracurium in healthy young adults undergoing general elective surgeries with no anticipated difficult endotracheal intubation had no effect on the quality of face mask ventilation despite resulting in a quantifiable improvement in the laryngeal view.