Hypoxemia during one-lung ventilation: prediction, prevention,

When switching from two-lung to one-lung ventilation (OLV), shunt fraction increases, oxygenation is impaired, and hypoxemia may occur. Hypoxemia during OLV may be predicted from measurements of lung function, distribution of perfusion between the lungs, whether the right or the left lung is ventilated, and whether the operation will be performed in the supine or in the lateral decubitus position. Hypoxemia during OLV may be prevented by applying a ventilation strategy that avoids alveolar collapse while minimally impairing perfusion of the dependent lung. Choice of anesthesia does not influence oxygenation during clinical OLV. Hypoxemia during OLV may be treated symptomatically by increasing inspired fraction of oxygen, by ventilating, or by using continuous positive airway pressure in the nonventilated lung. Hypoxemia during OLV may be treated causally by correcting the position of the double-lumen tube, clearing the main bronchi of the ventilated lung from secretions, and improving the ventilation strategy. ONE-LUNG ventilation (OLV) is required for a number of thoracic procedures, such as lung, esophageal, aortic, or mediastinal surgery. Although OLV is not mandatory for all such procedures, it almost always improves access to the operation field and expedites the process of operation. For this reason and because anesthesiologists' expertise in placement and monitoring of double-lumen tubes (DLTs) has increased, OLV is now used for almost all thoracic operations in which the lung is operated on or in which the collapse of the lung improves access to the operation field. During OLV, although only one lung is ventilated, both lungs are perfused. Perfusion of the collapsed, nonventilated lung leads inevitably to transpulmonary shunting, to impairment of oxygenation, and, occasionally, to hypoxemia. In a recent study, 1 we found that hypoxemia during OLV, defined by a decrease in arterial hemoglobin oxygen saturation (SaO 2 ) to less than 90%, occurred in 4% of patients whose lungs were ventilated with a fraction of inspired oxygen (FIO 2 ) greater than 0.5. Other studies 2-5 using similar definitions of hypoxemia place the rate at 5-10%. Hypoxemia during OLV may affect the safety of the patient and is a challenge for the anesthesiologist and for the surgeon. It is therefore important to predict, to prevent if possible, and to promptly treat hypoxemia during OLV. Prediction of Hypoxemia during OLV A number of factors may be helpful in predicting oxygenation during OLV. However, it must be kept in mind that none of these factors alone can accurately predict whether an individual patient will become hypoxemic during OLV. Side of Operation Because the right lung is larger than the left lung, it is not surprising that oxygenation during OLV is better during left thoracotomy (i.e., when the larger right lung is the dependent, ventilated lung). Lung Function Abnormalities Although lung function abnormalities may predispose to hypoxemia during OLV, not all measures of lung function are reliable indicators. Indeed, some studies show a clearly paradoxical effect: Some indicators of airway obstruction in lung function tests show a negative correlation with oxygenation during OLV, meaning that the more severe the obstruction is, the less likely it is that the patient will experience hypoxemia during OLV. In retrospective and prospective studies, Slinger et al. 2 found that the less the forced expiratory volume was in 1 s, the better the oxygenation was during OLV. One explanation provided for this paradoxical relation may be that air trapping in the ventilated lung may generate auto-positive end-expiratory pressure (PEEP) during OLV, thus decreasing the likelihood of atelectasis in the ventilated lung and improving oxygenation. Also, air trapping in the nonventilated lung may delay the onset of desaturation. However, other studies have not found any relation between degree of auto-PEEP and oxygenation during OLV, 7 and another recent study did not find Received from Klinik für Anästhesie und Intensivmedizin, Zentralklinik Bad Berka GmbH, Bad Berka, Germany, and Klinik für Anästhesiologie, Klinikum Saarbrücken, Saarbrücken, Germany. Submitted for publication August 26, 2008. Accepted for publication January 2, 2009. Support was provided solely from institutional and/or departmental sources. Literature search: The terms one-lung ventilation, single-lung ventilation, anesthesia and thoracic surgery, hypoxemia and thoracic surgery were used in MEDLINE (PubMed) to obtain a primary list of references. Titles, abstracts, and reference list of the primary list were then screened to obtain studies relevant to the topics in this review

A Special, Modified, Double-Lumen Tube for One-Lung Ventilation in Pigs

Animal studies in pigs often depend in thoracic anaesthesia on effective lung separation. In this report we describe the use of a modified double-lumen endotracheal tube for one-lung or differential lung ventilation in pigs resulting in excellent lung separation and unimpaired hypoxic pulmonary vasoconstriction

Development and validation of risk-adjusted quality indicators for the long-term outcome of acute sepsis care in German hospitals based on health claims data

Background Methods for assessing long-term outcome quality of acute care for sepsis are lacking. We investigated a method for measuring long-term outcome quality based on health claims data in Germany. Materials and methods Analyses were based on data of the largest German health insurer, covering 32% of the population. Cases (aged 15 years and older) with ICD-10-codes for severe sepsis or septic shock according to sepsis-1-definitions hospitalized in 2014 were included. Short-term outcome was assessed by 90-day mortality; long-term outcome was assessed by a composite endpoint defined by 1-year mortality or increased dependency on chronic care. Risk factors were identified by logistic regressions with backward selection. Hierarchical generalized linear models were used to correct for clustering of cases in hospitals. Predictive validity of the models was assessed by internal validation using bootstrap-sampling. Risk-standardized mortality rates (RSMR) were calculated with and without reliability adjustment and their univariate and bivariate distributions were described. Results Among 35,552 included patients, 53.2% died within 90 days after admission; 39.8% of 90-day survivors died within the first year or had an increased dependency on chronic care. Both risk-models showed a sufficient predictive validity regarding discrimination [ AUC = 0.748 (95% CI: 0.742; 0.752) for 90-day mortality; AUC = 0.675 (95% CI: 0.665; 0.685) for the 1-year composite outcome, respectively], calibration (Brier Score of 0.203 and 0.220; calibration slope of 1.094 and 0.978), and explained variance ( R 2 = 0.242 and R 2 = 0.111). Because of a small case-volume per hospital, applying reliability adjustment to the RSMR led to a great decrease in variability across hospitals [from median (1st quartile, 3rd quartile) 54.2% (44.3%, 65.5%) to 53.2% (50.7%, 55.9%) for 90-day mortality; from 39.2% (27.8%, 51.1%) to 39.9% (39.5%, 40.4%) for the 1-year composite endpoint]. There was no substantial correlation between the two endpoints at hospital level (observed rates: ρ = 0, p = 0.99; RSMR: ρ = 0.017, p = 0.56; reliability-adjusted RSMR: ρ = 0.067; p = 0.026). Conclusion Quality assurance and epidemiological surveillance of sepsis care should include indicators of long-term mortality and morbidity. Claims-based risk-adjustment models for quality indicators of acute sepsis care showed satisfactory predictive validity. To increase reliability of measurement, data sources should cover the full population and hospitals need to improve ICD-10-coding of sepsis

Adverse effects of delayed antimicrobial treatment and surgical source control in adults with sepsis: results of a planned secondary analysis of a cluster-randomized controlled trial

BACKGROUND: Timely antimicrobial treatment and source control are strongly recommended by sepsis guidelines, however, their impact on clinical outcomes is uncertain. METHODS: We performed a planned secondary analysis of a cluster-randomized trial conducted from July 2011 to May 2015 including forty German hospitals. All adult patients with sepsis treated in the participating ICUs were included. Primary exposures were timing of antimicrobial therapy and delay of surgical source control during the first 48 h after sepsis onset. Primary endpoint was 28-day mortality. Mixed models were used to investigate the effects of timing while adjusting for confounders. The linearity of the effect was investigated by fractional polynomials and by categorizing of timing. RESULTS: Analyses were based on 4792 patients receiving antimicrobial treatment and 1595 patients undergoing surgical source control. Fractional polynomial analysis identified a linear effect of timing of antimicrobials on 28-day mortality, which increased by 0.42% per hour delay (OR with 95% CI 1.019 [1.01, 1.028], p ≤ 0.001). This effect was significant in patients with and without shock (OR = 1.018 [1.008, 1.029] and 1.026 [1.01, 1.043], respectively). Using a categorized timing variable, there were no significant differences comparing treatment within 1 h versus 1–3 h, or 1 h versus 3–6 h. Delays of more than 6 h significantly increased mortality (OR = 1.41 [1.17, 1.69]). Delay in antimicrobials also increased risk of progression from severe sepsis to septic shock (OR per hour: 1.051 [1.022, 1.081], p ≤ 0.001). Time to surgical source control was significantly associated with decreased odds of successful source control (OR = 0.982 [0.971, 0.994], p = 0.003) and increased odds of death (OR = 1.011 [1.001, 1.021]; p = 0.03) in unadjusted analysis, but not when adjusted for confounders (OR = 0.991 [0.978, 1.005] and OR = 1.008 [0.997, 1.02], respectively). Only, among patients with septic shock delay of source control was significantly related to risk-of death (adjusted OR = 1.013 [1.001, 1.026], p = 0.04). CONCLUSIONS: Our findings suggest that management of sepsis is time critical both for antimicrobial therapy and source control. Also patients, who are not yet in septic shock, profit from early anti-infective treatment since it can prevent further deterioration. Trial registration ClinicalTrials.gov (NCT01187134). Registered 23 August 2010, NCT01187134 SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13054-022-03901-9

A multifaceted educational intervention improved anti-infectious measures but had no effect on mortality in patients with severe sepsis

Sepsis is a major reason for preventable hospital deaths. A cluster-randomized controlled trial on an educational intervention did not show improvements of sepsis management or outcome. We now aimed to test an improved implementation strategy in a second intervention phase in which new intervention hospitals (former controls) received a multifaceted educational intervention, while controls (former intervention hospitals) only received feedback of quality indicators. Changes in outcomes from the first to the second intervention phase were compared between groups using hierarchical generalized linear models controlling for possible confounders. During the two phases, 19 control hospitals included 4050 patients with sepsis and 21 intervention hospitals included 2526 patients. 28-day mortality did not show significant changes between study phases in both groups. The proportion of patients receiving antimicrobial therapy within one hour increased in intervention hospitals, but not in control hospitals. Taking at least two sets of blood cultures increased significantly in both groups. During phase 2, intervention hospitals showed higher proportion of adequate initial antimicrobial therapy and de-escalation within 5 days. A survey among involved clinicians indicated lacking resources for quality improvement. Therefore, quality improvement programs should include all elements of sepsis guidelines and provide hospitals with sufficient resources for quality improvement. Trial registration: ClinicalTrials.gov, NCT01187134. Registered 23 August 2010, https://www.clinicaltrials.gov/ct2/show/study/NCT01187134

Fever and hypothermia represent two populations of sepsis patients and are associated with outside temperature

Abstract Background Fever and hypothermia have been observed in septic patients. Their influence on prognosis is subject to ongoing debates. Methods We did a secondary analysis of a large clinical dataset from a quality improvement trial. A binary logistic regression model was calculated to assess the association of the thermal response with outcome and a multinomial regression model to assess factors associated with fever or hypothermia. Results With 6542 analyzable cases we observed a bimodal temperature response characterized by fever or hypothermia, normothermia was rare. Hypothermia and high fever were both associated with higher lactate values. Hypothermia was associated with higher mortality, but this association was reduced after adjustment for other risk factors. Age, community-acquired sepsis, lower BMI and lower outside temperatures were associated with hypothermia while bacteremia and higher procalcitonin values were associated with high fever. Conclusions Septic patients show either a hypothermic or a fever response. Whether hypothermia is a maladaptive response, as indicated by the higher mortality in hypothermic patients, or an adaptive response in patients with limited metabolic reserves under colder environmental conditions, remains an open question. Trial registration The original trial whose dataset was analyzed was registered at ClinicalTrials.gov (NCT01187134) on August 23, 2010, the first patient was included on July 1, 2011