Easy method to determine fluid responsiveness in septic shock patients: end-tidal CO2 - a prospective observational study.

BACKGROUND: In critically ill patients, especially those with septic shock, fluid management can be a challenging aspect of clinical care. One of the primary steps in treating patients with hemodynamic instability is optimizing intravascular volume. The Passive Leg Raising (PLR) maneuver is a reliable test for assessing fluid responsiveness, as demonstrated by numerous studies and meta-analyses. However, its use requires the measurement of cardiac output, which is often complex and may necessitate clinician experience and specialized equipment. End-Tidal Carbon Dioxide (ETCO2) measurement is relatively easy and is generally stable under steady metabolic conditions. It depends on the body's CO2 production, diffusion of CO2 from the lungs into the bloodstream, and cardiac output. If the other two parameters (metabolic conditions and minute ventilation) are constant, ETCO2 can provide information about cardiac output. The aim of the present study is to investigate the sensitivity of ETCO2 measurement in demonstrating fluid responsiveness. METHODS: All patients diagnosed with septic shock and meeting the inclusion criteria were subjected to a passive leg raising test, and cardiac outputs were measured by echocardiography. An increase in cardiac output of 15% or more was considered indicative of the fluid responder group, while patients with an increase below 15% or no increase were classified as the non-responder group. Patients' intensive care unit admission diagnoses, initial laboratory parameters, tidal volume, minute volume before and after the PLR maneuver, mean and systolic blood pressure, heart rate, Pulse Pressure Variation (PPV) values, and ETCO2 values were recorded. RESULTS: Before and after the ETCO2 test, there was no statistically significant difference between the two groups. However, the change in ETCO2 (ΔETCO2) was significantly higher in the responder group. In the non-responder group, ΔETCO2 was 2.57% (0.81), whereas it was 5.71% (2.83) in the responder group (p<0.001). Receiver Operating Characteristic (ROC) analysis was performed for ΔETCO2, baseline Stroke Volume Variation (SVV), ΔSVV, baseline Heart Rate (HR), ΔHR, baseline PPV, and ΔPPV to predict fluid responsiveness. ΔETCO2 predicted fluid responsiveness with a sensitivity of 85% and a specificity of 86% when it was 4% or higher. When ΔETCO2 was 5% or higher, it predicted fluid responsiveness with a specificity of 99.3% and a sensitivity of 75.5%, with an Area Under the Curve (AUC) of 0.89 (95% confidence interval, 0.828-0.961). CONCLUSION: This study demonstrates that in septic patients, ETCO2 during the PLR test can indicate fluid responsiveness with high sensitivity and specificity and can be used as an alternative to cardiac output measurement.

Clinical Significance of Pleural Lactate Measurement in Critically Ill Patients with Parapneumonic Pleural Effusion.

OBJECTIVE: Pleural fluid pH measurement is recommended for tube thoracostomy decisions in complicated parapneumonic pleural effusions. However, pleural fluid pH may be affected by blood pH in critically ill patients with common systemic acid-base disorders. We aimed to investigate the use of pleural fluid lactate to distinguish culture-positive parapneumonic effusions from other pleural effusions. MATERIAL AND METHODS: This prospective observational study included 121 eligible patients (51 female and 70 male). All patients with pleural effusion who underwent thoracentesis were assessed. Pleural fluid lactate was measured by a blood gas analyzer. RESULTS: Of the 121 patients, 30 (24.8%) were transudate and 91 (75.2%) were exudate. Of the 91 patients with exudative pleural effusion, 61 were diagnosed as culture-negative parapneumonic, 13 as culture-positive parapneumonic, 9 as malignant, and 8 as other exudative effusion. There was a strong positive linear association between serum pH and pleural fluid pH (R = 0.77, P < .001). The post hoc tests for pleural fluid lactate revealed there was a significant difference between culture-positive parapneumonic versus culture-negative parapneumonic groups (P = .004), culture-positive parapneumonic versus transudative effusion groups (P < .001), culture-negative parapneumonic versus transudative effusion groups (P = .008) and lastly; malignant effusion versus transudative effusion groups (P = .001). Receiver operating characteristics curve analysis for culture-positive parapneumonic indicated a cutoff of 4.55 mmol/L for pleural fluid lactate to have a sensitivity of 76.9% and a specificity of 84.3% (positive predictive value: 37%, negative predictive value: 96.8%). CONCLUSION: A cutoff of 4.55 mmol/L of pleural fluid lactate can be used as a useful tool to distinguish culture-positive parapneumonic effusions from other effusions in critically ill patients.

Dexmedetomidine may reduce the risk of acute kidney injury development in critically ill patients during colistin therapy.

INTRODUCTION: Colistin is considered as a last resort therapy for multidrug-resistant gram-negative organisms. It is widely used despite the significant risk of nephrotoxicity. Experimental studies showed the nephroprotective effect of dexmedetomidine, a sedative agent, against colistin toxicity. This study was performed to show the possible nephroprotective effect of dexmedetomidine among critically ill patients who received colistin. METHODS: Adult (>17 years) patients who were admitted to our surgical and medical intensive care unit (ICU) from March 2018 through March 2021, and who received colistin were included. Patients who receive Colistin therapy or intensive care unit follow-up of <72 h (discharge or death) and Acute kidney injury (AKI) or need hemodialysis prior to colistin therapy at the same hospitalization were excluded. AKI risk factors were examined by grouping patients with and without AKI. Patients, receiving colistin concomitantly with dexmedetomidine were also evaluated. RESULTS: Of the 139 patients included, 27 (17.8%) patients received dexmedetomidine. Sixty-five patients (47%) had AKI, at a median 5 (4-7) days after the initiation of colistin. Older age, lower baseline estimated glomerular filtration rate, and vasopressor use were associated with a higher risk of AKI, while dexmedetomidine use was associated with a lower risk. In the multivariate regression model, dexmedetomidine use was independently associated with a lower risk of AKI development (OR 0.20 95% CI 0.07-0.59, p = 0.003). CONCLUSION: In respect to these findings, dexmedetomidine may provide protection against AKI during colistin therapy in critically ill patients.

The Safety of Fiberoptic Bronchoscopy in Airway Pressure Release Ventilation Mode in Critically Ill Patients with Severe Acute Respiratory Distress Syndrome: A Preliminary Study.

OBJECTIVE: The most appropriate ventilatory mode during fiberoptic bronchoscopy is still not yet known clearly for patients with acute respiratory distress syndrome. Airway pressure release ventilation is used as a recovery treatment for patients with severe acute respiratory distress syndrome. In this study, the aim was to evaluate the safety of the fiberoptic bronchoscopy process in patients with severe acute respiratory distress syndrome ventilated with airway pressure release ventilation mode and its effect on gas exchange and respiratory mechanics. MATERIAL AND METHODS: Single-center retrospective observational study was performed in the intensive care unit of a tertiary referral center from September 2018 to November 2019. Patients with severe ARDS ventilated with APRV mode and undergoing FB were included. Fiberoptic bronchoscopy was performed by an expert intensivist-pulmonologist. All ventilator parameters set by the clinician were kept stable, and no change was made other than O2 concentration. The mechanical ventilation parameters and arterial blood gas values before and after the procedure and fiberoptic bronchoscopy-related complications were recorded for the first 24 hours. RESULTS: A total of 14 acute respiratory distress syndrome patients who were ventilated with airway pressure release ventilation were enrolled. No significant deteriorations were detected in gas exchange, pulmonary compliance, and airway resistance values in our case series. It was observed that a small reduction in PaO2 and an increase in PaCO2 were present after the 1st hour; however, both were returned to baseline values in the 24th hour. Only 1 patient developed fiberoptic bronchoscopy-induced hypoxemia (7.1%). Complications, such as fiberoptic bronchoscopy-induced barotrauma, pneumothorax, hemodynamic deterioration, and bleeding, were not detected. CONCLUSION: According to our preliminary findings, performing fiberoptic bronchoscopy under airway pressure release ventilation mode by an experienced bronchoscopist does not bring additional complication risks in patients with severe acute respiratory distress syndrome.

The Impact of Mechanical Ventilation Modes on Complications of Fiberoptic Bronchoscopy in Critically Ill Patients.

OBJECTIVE: The effects of fiberoptic bronchoscopy are not elucidated in different mechanical ventilation modes. The present study aimed to evaluate the effects of fiberoptic bronchoscopy on lung mechanics, ventilation parameters, and gas exchange in 2 often-used modes, volume control and pressure control, in invasively ventilated patients followed up in the intensive care unit. MATERIAL AND METHODS: Eligible patients were screened and included in the study after intensive care unit-fiberoptic bronchoscopy database search. Patients who underwent fiberoptic bronchoscopy under volume control and pressure control mechanical ventilation modes were compared. The primary outcome was the occurrence of any complication within the first 24 hours after the procedure, and secondary outcomes were changes in lung mechanics (dynamic lung compliance and airway resistance) and gas exchange (arterial partial pressures of oxygen and carbon dioxide). RESULTS: A total of 61 patients (median age: 69 years, 60.7% male) were included. Twenty-nine (47.5%) patients were ventilated in volume control mode and 32 (52.5%) in pressure control mode during the fiberoptic bronchoscopy procedure, and the median (interquartile range) duration of the procedure was 9 [8-11] minutes. Baseline dynamic lung compliance, airway resistance, arterial partial pressures of oxygen and carbon dioxide, and the fraction of inspired O2 were similar in both groups. After fiberoptic bronchoscopy, dynamic lung compliance decreased in both groups, and airway resistance and peak airway pressures increased but reached pre-fiberoptic bronchoscopy values at the 1st hour after the procedure. No significant differences were detected in both groups in terms of blood gas values and lung mechanics in the 1st and 24th hours after the procedure. In both groups, the 24th hour fraction of inspired O2 was the same as the pre-fiberoptic bronchoscopy values, but the ratio of arterial partial pressure of oxygen and the fraction of inspired O2 improved. No complications developed in patients within 24 hours after the procedure. CONCLUSION: No differences were detected in terms of gas exchange and pulmonary mechanics, and complications in volume control and pressure control modes in critically ill intubated patients.

Comparison of minimal-flow sevoflurane versus desflurane anesthesia: randomized clinical trial.

BACKGROUND AND OBJECTIVES: Minimal-flow anesthesia provides various advantages, such as reduced environmental pollution, proper humidification and warming of anesthetic gases, and reduced costs. The aim of this study was to compare the cost-effectiveness of minimal-flow sevoflurane and desflurane anesthesia and their effects on hemodynamics, postoperative recovery, respiratory parameters, and liver and kidney functions. METHODS: A total of 60 ASA I-II patients aged 18-70 years who underwent posterior spinal instrumentation were included in the study. The patients were divided into Group S (sevoflurane) and Group D (desflurane). After anesthesia induction, the gas flow was initiated at a rate of 4 L.min-1 using a concentration of 8% in Group D and 3.5% in Group S, and the time to reach 0.8 MAC was recorded. The gas flow was then switched to minimal flow. Patient hemodynamic and respiratory parameters, body temperatures and arterial blood gas levels were recorded. The integrated pulmonary index (IPI) was monitored postoperatively. Biochemical findings were recorded 12 hours after the operation. The amount of bleeding and blood transfused, and the costs involved were calculated. RESULTS: The patients' demographic characteristics, duration of surgery, hemodynamic parameters, IPI values, body temperatures, and arterial blood gas levels were similar at all time points. Biochemical findings, amount of bleeding and amount of blood transfused were similar between the two groups. The mean cost was lower in Group S than in Group D (p = 0.007). CONCLUSION: The study found no significant difference in terms of reliability between minimal-flow sevoflurane and desflurane anesthesia. Furthermore, the procedure was found to be more cost-effective for Group S than for Group D.

Is serum magnesium level associated with atrial fibrillation in the mixed medical/surgical intensive care unit setting?

Background: Although low serum magnesium level is a a relatively common problem in mixed medical/surgical intensive care units (ICUs), its association with new-onset atrial fibrillation (NOAF) has been studied to a lesser extent. We aimed to investigate the effect of magnesium levels on the development of NOAF in critically ill patients admitted to the mixed medical/surgical ICU. Methods: A total of 110 eligible patients (45 female, 65 male) were included in this case-control study. The age and sex-matched control group (n = 110) included patients with no atrial fibrillation from admission to discharge or death. Results: The incidence of NOAF was 2.4% (n = 110) between January 2013 and June 2020. At NOAF onset or the matched time point, median serum magnesium levels were lower in the NOAF group than in the control group (0.84 [0.73-0.93] vs. 0.86 [0.79-0.97] mmol/L; p = 0.025). At NOAF onset or the matched time point, 24.5% (n = 27) in the NOAF group and 12.7% (n = 14) in the control group had hypomagnesemia (p = 0.037). Based on Model 1, multivariable analysis demonstrated magnesium level at NOAF onset or the matched time point (OR: 0.07; 95%CI: 0.01-0.44; p = 0.004), acute kidney injury (OR: 1.88; 95%CI: 1.03-3.40; p = 0.039), and APACHE II (OR: 1.04; 95% CI: 1.01-1.09; p = 0.046) as factors independently associated with an increased risk of NOAF. Based on Model 2, multivariable analysis demonstrated hypomagnesemia at NOAF onset or the matched time point (OR: 2.52; 95% CI: 1.19-5.36; p = 0.016) and APACHE II (OR: 1.04; 95%CI: 1.01-1.09; p = 0.043) as factors independently associated with an increased risk of NOAF. In multivariate analysis for hospital mortality, NOAF was an independent risk factor for hospital mortality (OR: 3.22; 95% CI: 1.69-6.13, p<0.001). Conclusion: The development of NOAF in critically ill patients increases mortality. Critically ill patients with hypermagnesemia should be carefully evaluated for risk of NOAF.