The Effect of Switching from Volume-Controlled to Pressure-Controlled Ventilation on Respiratory Distress and Asynchrony Index Improvement among Mechanically Ventilated Adults.

Background: It is important to synchrony the time, intensity, and respiratory signal of the phrenic nerve between the patient and the ventilator. This study aimed to evaluate the effect of switching from volume-controlled to pressure-controlled ventilation on respiratory distress and asynchrony index improvement. Materials and Methods: In this randomized controlled clinical trial, 70 patients admitted to the intensive care unit under mechanical ventilation were included. Asynchronous evaluation was performed by examining the patient and evaluating and analyzing the graphic flow curve and ventilator pressure, which included trigger and flow asynchronous and asynchronous cycling. In the intervention group, the mode of ventilation was switched to PSIMV such that peak inspiratory pressures would be equivalent to positive end-expiratory pressure (PEEP) in the volume-controlled mode. Finally, again at 60, 75, and 90 min, information about the ventilator and the patient's symptoms, and arterial carbon dioxide levels were sent by arterial gas sample. The asynchronous index was also recorded in both groups. Results: This study showed that the mean of variables such as height, ideal body weight, tidal volume, set rate; Sense, FiO2, PEEP did not differ significantly between the two groups. The mean of asynchrony was significantly reduced in both control group (16.51 ± 3.35-14.51 ± 2.90; P < 0.001) and intervention group (18.26 ± 6.13-13.32 ± 5.53; P < 0.001). Conclusion: Regardless of the type and severity of the disease, switching the ventilation mode from volume-controlled to pressure-controlled can improve patient adaptation to the ventilator, especially in cases with frequent asynchrony.

Estimating the best fraction of inspired oxygen for calculation of PaO2/FiO2 ratio in acute respiratory distress syndrome due to COVID-19 pneumonia.

Background: The ratio of partial pressure of oxygen in arterial blood (PaO2) to the fraction of inspiratory oxygen concentration (FiO2) is an indicator of pulmonary shunt fraction. PaO2/FiO2 (P/F) ratio is used to classify severity of acute respiratory distress syndrome (ARDS). With the same shunt fraction, P/F ratio decreases with increases in FiO2 which may lead to errors in classifying severity of ARDS. The effect of FiO2 on P/F ratio has not been investigated in COVID-19 pneumonia. In this study, we estimated the best FiO2 for the calculation of P/F ratio in a sample of patients with ARDS due to COVID-19 pneumonia. Materials and Methods: Blood gas and ventilatory data of 108 COVID-19 ARDS patients were analyzed in a cross-sectional observational study. Using Oxygen Status Algorithm the calculated shunt fraction served a basis for calculating P/F ratio for different FiO2. The severity of ARDS determined by P/F ratios at each FiO2s was compared with the shunt-based severity to find the optimum FiO2 for calculation of P/F ratio so the resulting classification has the best match with the reference classification. Results: A FiO2 of 1.0 for calculation of P/F ratio and ARDS classification showed the best match with shunt-based ARDS classification. A regression model was obtained with the PaO2, patient's original FiO2, Hemoglobin concentration, and SaO2 as the independent predictors of the P/F ratio for the FiO2 of 1.0. Conclusion: This study shows a FiO2 of 1.0 as the best value for correct calculation of P/F ratio and proper classification of ARDS.

Expanding unilateral lung collapse using airway pressure release ventilation applied independently to the collapsed lung through the double-lumen endotracheal tube.

Unilateral lung collapse (ULC) is a clinical challenge in the intensive care unit and requires sophisticated treatment approaches, especially if the collapse continued over several hours. If not responded to ordinary measures such as postural drainage and bronchoscopy, it may require insertion of a double-lumen endotracheal tube and independent lung ventilation or high-pressure manual re-expansion of the collapsed lung which may result in lung injury. In this article, a safe and gradual re-expansion method using airway pressure release ventilation is presented for the treatment of a ULC.

Identifying the dimensions of patient privacy in intensive care units: a qualitative content analysis study.

In intensive care units (ICUs), patient privacy is of particular importance due to the structure of the ward environment and the critical situation of the patients. The aim of this study was to identify the dimensions of patient privacy in ICUs. For this purpose, a descriptive-qualitative-exploratory study was performed. The data collection methods included observations and interviews, which were handwritten and analyzed using qualitative content analysis with a conventional approach. A total of 27 participants were selected based on purposeful sampling and with maximum diversity of health-care providers and recipients. The study environment was the ICUs of two selected hospitals affiliated to the medical sciences universities of Isfahan and Tehran, Iran. The data were analyzed into 4 classes and 12 subclasses. The classes included physical, informational, psychosocial, and spiritual-religious privacy. Findings of the present study identified hidden layers of patient privacy as a multidimensional concept that is influenced by various factors. In order to provide holistic care, preparing the grounds for patient privacy and familiarizing the staff with its various dimensions seem necessary.

Ventilator Mode Finder: An Android application to find equivalent of a mode on different ventilators.

There are hundreds of ventilator modes on different ventilators. Despite different names, many are similar in functions and options. Educational institutions only teach a limited collection of ventilator modes of a few numbers of models; therefore, graduates may have substantial difficulties encountering new ventilator models with unfamiliar mode names on them. In this article, an Android application for finding similar modes on different ventilators is presented. The aim is to help an intensive care practitioner to easily find a familiar mode on a new ventilator.

Effects of Open and Closed Tracheal Suctioning on Pain in Mechanically Ventilated Patients.

BACKGROUND: Painful care procedures are the most common cause of stress in patients admitted to Intensive Care Units (ICUs). Tracheal suctioning is the most painful experience for ICU patients. The present study was conducted to compare open and closed endotracheal suctioning in terms of their effect in pain in mechanically ventilated patients. MATERIALS AND METHODS: The present clinical trial recruited 70 mechanically ventilated patients with tracheostomy in 2019. The eligible patients were randomly divided into open and closed suctioning groups. The pain was measured in the patients using the Critical Pain Observational Tool (CPOT) before and during suctioning as well as 10 and 30 min later. The data were analyzed using the repeated measures Analysis Of Variance (ANOVA), paired t-test, and Chi-squared test. RESULTS: The pain score was significantly higher in the open suctioning group during (t = 2.59, p = 0.01) and 10 min after suctioning (t = 3.02, p = 0.004). No significant differences were observed in the pain score between the two groups 30 min after suctioning (t = 0.32, p = 0.75). The post hoc Least Significant Difference (LSD) test showed that the CPOT scores 10 min after suctioning was significantly higher than that before suctioning and significantly lower than that during suctioning (p = 0.001). The CPOT score 30 min after suctioning was also significantly lower than that 10 min after suctioning (p < 0.001). CONCLUSIONS: The present findings suggested a lower pain in the patients with closed suctioning compared to those with open suctioning.

Effect of interprofessional education of medication safety program on the medication error of physicians and nurses in the intensive care units.

BACKGROUND: The safety of hospitalized patients in the intensive care units (ICUs) is threatened due to incidents and adverse events, including medication errors. Medication error refers to any preventable event at different stage of medication process, such as prescription, transcription, distributing medication, and administration, which can lead to incorrect use of medicines or damage to the patient. This study aimed at investigating the effect of the interprofessional education of medication safety program on medication errors of physicians and nurses in the ICUs. MATERIALS AND METHODS: The study was conducted using a quasi-experimental method (single group, before and after) in 2017. The setting of the study included one ICU of selected teaching hospital affiliated to Isfahan University of Medical Sciences located in the Central Iran with a total of 23 beds. Participants included 50 members of the health-care team (physician, nurse, and clinical pharmacist) with at least 1 year of work experience in the ICUs. Participants were selected using censuses sampling method. Data were collected using a two-section self-made questionnaire. Data were analyzed through descriptive, analytical statistics, and version 16 of the SPSS software (P < 0.05). RESULTS: According to reporting of physicians, nurses, and clinical pharmacist, the medication error 1 month after implementation, the interprofessional education of medication safety program was significantly lower than before the implementation of it (P < 0.001). CONCLUSIONS: Interprofessional education helps to improve interprofessional collaboration and patient care through the promotion of various professions of health to increase interprofessional collaboration compared to single profession education, which individuals learn in isolation and merely in their profession. Therefore, interprofessional education of medication safety program can reduce medication error and promote patient safety in the ICUs.

Tracheal Sound Analysis for Automatic Detection of Respiratory Depression in Adult Patients during Cataract Surgery under Sedation.

BACKGROUND: Tracheal sound analysis is a simple way to study the abnormalities of upper airway like airway obstruction. Hence, it may be an effective method for detection of alveolar hypoventilation and respiratory depression. This study was designed to investigate the importance of tracheal sound analysis to detect respiratory depression during cataract surgery under sedation. Methods: After Institutional Ethical Committee approval and informed patients' consent, we studied thirty adults American Society of Anesthesiologists I and II patients scheduled for cataract surgery under sedation anesthesia. Recording of tracheal sounds started 1 min before administration of sedative drugs using a microphone. Recorded sounds were examined by the anesthesiologist to detect periods of respiratory depression longer than 10 s. Then, tracheal sound signals converted to spectrogram images, and image processing was done to detect respiratory depression. Finally, depression periods detected from tracheal sound analysis were compared to the depression periods detected by the anesthesiologist. RESULTS: We extracted five features from spectrogram images of tracheal sounds for the detection of respiratory depression. Then, decision tree and support vector machine (SVM) with Radial Basis Function (RBF) kernel were used to classify the data using these features, where the designed decision tree outperforms the SVM with a sensitivity of 89% and specificity of 97%. CONCLUSIONS: The results of this study show that morphological processing of spectrogram images of tracheal sound signals from a microphone placed over suprasternal notch may reliably provide an early warning of respiratory depression and the onset of airway obstruction in patients under sedation.

The most frequent and important events that threaten patient safety in intensive care units from the perspective of health-care professionals'.

BACKGROUND: Patient safety is a priority in all health-care centers across the world. This study aimed to determine the frequency of events that threaten patient safety and the grade threating of events from the perspective of the health-care professionals in the intensive care units (ICUs). MATERIALS AND METHODS: This cross-sectional study was conducted in 2016. The participants were 306 members of health-care professionals (physicians and nurses) with at least 1 year of work experience in ICUs of educational hospitals affiliated to Isfahan University of Medical Sciences. Data were collected using a three-section self-made questionnaire. Data analysis was done using descriptive statistics (frequency distribution and percentage) and version 16 of SPSS software. RESULTS: A total of 306 questionnaires were completed out of 320 questionnaires handed out among participants. During the last month, 91.2% of the participants had reported at least a case of medication error, 75.6% had reported at least a case of ventilator-associated pneumonia, and 74.2% had reported at least a case of catheter-induced urinary infection in ICUs. CONCLUSION: The occurrence of events threatening the patient safety in ICUs warrants proper planning by administrators of health-care centers. Medication error was the most frequent and important event of threat to patient safety and falling was the least frequent event of threat to patient safety in ICUs. Considering the frequency and magnitude of medication error in ICUs, a well-adjusted preventive plan should be designed and implemented to improve the patient safety.

Causes of Medication Errors in Intensive Care Units from the Perspective of Healthcare Professionals.

OBJECTIVE: This study was conducted to explore and to describe the causes of medication errors in Intensive Care Units (ICUs) from the perspective of physicians, nurses, and clinical pharmacists. METHODS: The study was conducted using a descriptive qualitative method in 2016. We included 16 ICUs of seven educational hospitals affiliated to Isfahan University of Medical Sciences. Participants included 19 members of the healthcare team (physician, nurse, and clinical pharmacist) with at least 1 year of work experience in the ICUs. Participants were selected using purposeful sampling method. Data were collected through semi-structured individual interviews and were used for qualitative content analysis. FINDINGS: The four main categories and ten subcategories were extracted from interviews. The four categories were as follows: "low attention of healthcare professionals to medication safety," "lack of professional communication and collaboration," "environmental determinants," and "management determinants." CONCLUSION: Incorrect prescribing of physicians, unsafe drug administration of nurses, the lack of pharmaceutical knowledge of the healthcare team, and the weak professional collaboration lead to medication errors. To improve patient safety in the ICUs, healthcare center managers need to promote interprofessional collaboration and participation of clinical pharmacists in the ICUs. Furthermore, interprofessional programs to prevent and reduce medication errors should be developed and implemented.

Effect of ondansetron on prevention of post-induction hypotension in elderly patients undergoing general anesthesia: A randomized, double-blind placebo-controlled clinical trial.

BACKGROUND: Elderly patients are susceptible to post-induction hypotension. Volume loading and vasopressors for prevention of hypotension in elderly patients may increase perioperative cardiovascular risks. Ondansetron by blocking Bezold-Jarisch reflex (BJR) through inhibition of serotonin receptors has been effective in the prevention of post-spinal hypotension, and bradycardia. Bradycardia frequently accompanies post-induction hypotension in elderly patients, which signifies a possible preventing role for ondansetron. No previous study has evaluated the prophylactic effects of ondansetron for the prevention of post-induction hypotension. MATERIALS AND METHODS: In this randomized placebo-controlled clinical trial, ondansetron 4 mg was given intravenously to 65 elderly patients, 20 min before induction of general anesthesia, and the rate of post-induction hypotension defined as 25% or more reduction in mean arterial blood pressure, compared with a placebo groups. RESULTS: A total of 114 patients completed the study (58 in ondansetron and 56 in the placebo group). Proportions of post-induction hypotension were 9 (16%) and 25 (45%) in ondansetron and placebo groups, respectively, (P = 0.001). Forty-five patients (40%) developed bradycardia. Rates of bradycardia were not significantly different between two groups. CONCLUSIONS: The results of this study show the effectiveness of intravenous ondansetron for prevention of post-induction hypotension in elderly patients. The mechanism of this effect largely is unknown. Role of ondansetron for prevention of post-induction hypotension may not fully understandable by its interaction with BJR, as has been shown in post-spinal hypotension.

Effects of intra-operative end-tidal carbon dioxide levels on the rates of post-operative complications in adults undergoing general anesthesia for percutaneous nephrolithotomy: A clinical trial.

BACKGROUND: A retrospective study has shown lesser days of hospital stay in patients with increased levels of intra-operative end-tidal carbon dioxide (ETCO2). It is probable that hypercapnia may exert its beneficial effects on patients' outcome through optimization of global hemodynamic and tissue oxygenation, leading to a lower rate of post-operative complications. This study was designed to test the hypothesis that higher values of intra-operative ETCO2 decrease the rate of post-operative complications. MATERIALS AND METHODS: In this randomized, double-blind clinical trial, 78 adult patients scheduled for percutaneous nephrolithotomy (PCNL) were prospectively enrolled and randomly divided into three groups. ETCO2 was set and maintained throughout the procedure at 31-33, 37-39 and 43-45 mmHg in the hypocapnia, normocapnia and hypercapnia groups, respectively. The rates of post-operative complications were compared among the three groups. RESULTS: Seventy-five patients completed the study (52 male and 23 female). Ten (38.5%), four (16%) and two (8.3%) patients developed post-operative vomiting in the hypocapnia, normocapnia and hypercapnia groups, respectively (P = 0.025). The nausea score was significantly lower in the hypercapnic group compared with the other groups (3.9 ± 1.8, 3.2 ± 2.1 and 1.3 ± 1.8 in the hypocapnia, normocapnia and hypercapnia groups, respectively; P = 0.000). Time to return of spontaneous respiration and awakening were significantly decreased in the hypercapnia group compared with the other groups (P < 0.01). CONCLUSION: Mild intra-operative hypercapnia has a protecting effect against the development of post-operative nausea and vomiting and decreases the duration of emergence and recovery from general anesthesia.

Comparing two levels of closed system suction pressure in ICU patients: Evaluating the relative safety of higher values of suction pressure.

BACKGROUND: Endotracheal suctioning (ETS) is one of the most common supportive measures in intensive care units (ICU). ETS may be associated with complications including hypoxia and tachycardia. Closed system suctioning (CSS) decreases the rate of cardiorespiratory complication mainly due to continuation of ventilatory support and oxygenation during procedure. CSS has questionable efficacy, therefore higher values of negative pressure has been recommended to enhance the efficacy of CSS. This study was designed to evaluate the effects on gas exchange of 200 mmHg suctioning pressure compared with 100 mmHg in CSS. MATERIALS AND METHODS: Fifty mechanically ventilated (MV) ICU patients were selected for the study. Two consecutive ten seconds CSS using suction pressures of 100 and 200 mmHg, in random order applied in each subject with the two hours wash out period. Effects of two levels of suction pressure on gas exchange were measured by recording the SPo2 values at 4 times. RESULTS: Repeated measure analysis of variance didn't show any significant difference between two levels of pressure (P = 0.315), but within each groups (100 and 200 mmHg) SPO2 changes was significant (P = 0.000). There was a mild but significant and transient increase in heart rate following both suction pressures, but no significant difference between two groups. CONCLUSION: The results show that CSS with suction pressure 200 mmHg has no detrimental effect on cardiorespiratory function of MV ICU patients. Since the safety of 200 mmHg suctioning pressure was approved, using 200 mmHg suction pressures is recommended for ETS of MV patients.

Predicting efficiency of post-induction mask ventilation based on demographic and anatomical factors.

BACKGROUND: Failure to ventilate patients by mask leads to serious complications especially if associated with difficult intubation. Previous studies have used subjective and indirect measures to evaluate difficulty in mask ventilation, which are associated with high inter-observer discrepancies. In this study, we have defined and used efficiency of mask ventilation (EMV) as an objective and direct surrogate for ease of mask ventilation in patients undergoing GA and mask ventilation using neuromuscular relaxation. MATERIALS AND METHODS: 1050 adult patients prospectively were evaluated with respect to different patients demographic and physical factors and EMV. EMV was defined as the ratio of minute ventilation via anesthesia mask to that via tracheal tube expressed as percentage. Edentolous patients were ventilated using lip-over-mask techniques. Separate analyses were done for edentolous and non-edentolous patients. RESULTS: EMV in edentolous patients (n=269) using the lip-over-mask method was relatively high (90.9 ± 14.3%, 60.14-128.57 range). The result of multiple regression analysis in patients with normal denture determined receded chin, presence of beard, male gender, high Mallampati classes, high neck circumference, low inter-incisors gap, and old age as independent factors for estimating EMV. A regression formula for predicting EMV was developed which had an acceptable R-square value with a good model fit. CONCLUSIONS: Using EMV is an easy and reliable tool for measuring efficiency of mask ventilation. Based on the result of this study, EMV can be estimated from patient's demographic and physical factors. In edentolous patients, using the lip-over-mask method results in adequate ventilation of lungs.

Benzodiazepines co-ingestion in reducing tricyclic antidepressant toxicity.

AIM: Tricyclic antidepressant (TCA) overdose is generally associated with central nervous system (CNS) and cardiovascular toxicity manifested by seizure, electrocardiographic (ECG) abnormalities and arrhythmia. The objective of this study was to determine whether TCA toxicity would be reduced in patient where benzodiazepine (BDZ) was co-ingested with TCA. DESIGN: Patients who were diagnosed to be poisoned by ingestion of both a tricyclic antidepressant and benzodiazepine (TCA-BDZ), and patients intoxicated solely by a TCA were assessed, provided that they had one or more clinical signs of toxicity (anticholinergic, cardiovascular or CNS findings) and no underlying cardiac disease. TCA poisoned patients who had ingested any drugs other than benzodiazepines were excluded. Patients transferred from elsewhere and those admitted after the first 24 hours were also excluded. The clinical manifestations of TCA toxicity and outcome of the patients poisoned only with TCA (N = 60) were compared with those of the patients who had co-ingested TCAs and BDZs (N = 60). MAIN RESULTS: The frequency distribution of sinus tachycardia, "QRS more than 100 ms, R/S aVR equal or more than 0.7, RaVR equal or more than 3 mm", arrhythmia, and generalized tonic colonic seizure was less in patients who had co-ingested BDZ with TCA. Evaluating the relationship between ingested TCA dosage and electrocardiographic findings (duration of QRS, QT and PR intervals, the amplitude of R wave in lead aVR and right axis deviation) in both study groups, demonstrated that there was a strong relationship between TCA dosage and QRS duration in the TCA group. This was significantly different from the same correlation in the TCA-BDZ group (r, 0.50 in TCA group versus r, 0.04 in TCA and BDZ group, P < 0.05). No significant differences were found in complications (aspiration pneumonia, non-cardiac pulmonary oedema and death) between the two groups. CONCLUSIONS: cardiovascular toxicity and seizure may be less in TCA-BDZ poisoned patients compared with patients intoxicated with TCA-alone.

An overview of randomization and minimization programs for randomized clinical trials.

Randomization is an essential component of sound clinical trials, which prevents selection biases and helps in blinding the allocations. Randomization is a process by which subsequent subjects are enrolled into trial groups only by chance, which essentially eliminates selection biases. A serious consequence of randomization is severe imbalance among the treatment groups with respect to some prognostic factors, which invalidate the trial results or necessitate complex and usually unreliable secondary analysis to eradicate the source of imbalances. Minimization on the other hand tends to allocate in such a way as to minimize the differences among groups, with respect to prognostic factors. Pure minimization is therefore completely deterministic, that is, one can predict the allocation of the next subject by knowing the factor levels of a previously enrolled subject and having the properties of the next subject. To eliminate the predictability of randomization, it is necessary to include some elements of randomness in the minimization algorithms. In this article brief descriptions of randomization and minimization are presented followed by introducing selected randomization and minimization programs.