Tissue oxygenation as a target for goal-directed therapy in high-risk surgery: a pilot study

Association between muscular tissue desaturation and acute kidney injury in older patients undergoing major abdominal surgery: a prospective cohort study

PURPOSE

Present study was designed to investigate the association between muscular tissue desaturation and acute kidney injury (AKI) in older patients undergoing major abdominal surgery.

METHOD

A total of 253 patients (≥ 65 years old) who underwent abdominal surgery with expected duration ≥ 2 h were enrolled. Muscular tissue oxygen saturation (SmtO2) was monitored at quadriceps and bilateral flanks during surgery. Muscular desaturation was defined as SmtO2 < 90% baseline lasting for > 60 s. The primary outcome was the incidence of AKI within postoperative 7 days. The association between muscular desaturation and AKI was analyzed by multivariable logistic regression model. The secondary outcomes indicated the other complications within postoperative 30 days.

RESULTS

Among 236 patients, 44 (18.6%) of them developed AKI. The incidence of muscular desaturation at quadriceps was 28.8% (68/236). Patients with muscular desaturation had higher incidence of AKI than those without desaturation (27.9% [19/68], vs. 14.9% [25/168], P = 0.020). After adjustment of confounders, multivariable analysis showed that muscular desaturation at quadriceps was significantly associated with an increased risk of AKI (OR = 2.84, 95% CI 1.21-6.67, P = 0.016). Muscular desaturations at left and right flank were also associated with an increased risk of AKI (OR = 6.38, 95% CI 1.78-22.89, P = 0.004; OR = 8.90, 95% CI 1.42-45.63; P = 0.019, respectively). Furthermore, patients with muscular desaturation may have a higher risk of pulmonary complications, sepsis and stroke at 30-day follow-up.

CONCLUSION

Muscular desaturation was associated with postoperative AKI in older patients undergoing major abdominal surgery which may serve as a predictor of AKI.

Effective hemodynamic monitoring

Hemodynamic monitoring is the centerpiece of patient monitoring in acute care settings. Its effectiveness in terms of improved patient outcomes is difficult to quantify. This review focused on effectiveness of monitoring-linked resuscitation strategies from: (1) process-specific monitoring that allows for non-specific prevention of new onset cardiovascular insufficiency (CVI) in perioperative care. Such goal-directed therapy is associated with decreased perioperative complications and length of stay in high-risk surgery patients. (2) Patient-specific personalized resuscitation approaches for CVI. These approaches including dynamic measures to define volume responsiveness and vasomotor tone, limiting less fluid administration and vasopressor duration, reduced length of care. (3) Hemodynamic monitoring to predict future CVI using machine learning approaches. These approaches presently focus on predicting hypotension. Future clinical trials assessing hemodynamic monitoring need to focus on process-specific monitoring based on modifying therapeutic interventions known to improve patient-centered outcomes.

Perioperative goal-directed therapy and postoperative complications in different kind of surgical procedures: an updated meta-analysis

BACKGROUND

Goal-directed therapy (GDT) aims to assure tissue perfusion, by optimizing doses and timing of fluids, inotropes, and vasopressors, through monitoring of cardiac output and other basic hemodynamic parameters. Several meta-analyses confirm that GDT can reduce postoperative complications. However, all recent evidences focused on high-risk patients and on major abdominal surgery.

OBJECTIVES

The aim of the present meta-analysis is to investigate the effect of GDT on postoperative complications (defined as number of patients with a least one postoperative complication) in different kind of surgical procedures.

DATA SOURCES

Randomized controlled trials (RCTs) on perioperative GDT in adult surgical patients were included. The primary outcome measure was complications, defined as number of patients with at least one postoperative complication. A subgroup-analysis was performed considering the kind of surgery: major abdominal (including also major vascular), only vascular, only orthopedic surgery. and so on.

STUDY APPRAISAL AND SYNTHESIS METHODS

Meta-analytic techniques (analysis software RevMan, version 5.3.5, Cochrane Collaboration, Oxford, England, UK) were used to combine studies using odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

In 52 RCTs, 6325 patients were enrolled. Of these, 3162 were randomized to perioperative GDT and 3153 were randomized to control. In the overall population, 2836 patients developed at least one complication: 1278 (40%) were randomized to perioperative GDT, and 1558 (49%) were randomized to control. Pooled OR was 0.60 and 95% CI was 0.49-0.72. The sensitivity analysis confirmed the main result. The analysis enrolling major abdominal patients showed a significant result (OR 0.72, 95% CI 0.59-0.87, p = 0.0007, 31 RCTs, 4203 patients), both in high- and low-risk patients. A significant effect was observed in those RCTs enrolling exclusively orthopedic procedures (OR 0.53, 95% CI 0.35-0.80, p = 0.002, 7 RCTs, 650 patients. Also neurosurgical procedures seemed to benefit from GDT (OR 0.40, 95% CI 0.21-0.78, p = 0.008, 2 RCTs, 208 patients). In both major abdominal and orthopedic surgery, a strategy adopting fluids and inotropes yielded significant results. The total volume of fluid was not significantly different between the GDT and the control group.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The present meta-analysis, within the limits of the existing data, the clinical and statistical heterogeneity, suggests that GDT can reduce postoperative complication rate. Moreover, the beneficial effect of GDT on postoperative morbidity is significant on major abdominal, orthopedic and neurosurgical procedures. Several well-designed RCTs are needed to further explore the effect of GDT in different kind of surgeries.

Monitoring adaptation of skin tissue oxygenation during cycling ergometer exercise by frequency-domain diffuse optical spectroscopy

In addition to supplying oxygen molecule O2 for metabolic functions during the adaptation to exercise, blood also plays a critical role in heat dissipation for core temperature stabilization. This study investigates the status of hemodynamic oxygenation in the forearm's skin tissue of three participants during a complete ergometer exercise from the resting to exercising, and to recovering conditions using a three-wavelength frequency-domain diffuse reflectance spectroscopy (FD DRS) alongside the monitoring of heartbeat rate and skin temperature. The FD DRS system was synchronized with radiofrequency (RF)-modulated input photon sources and the respective output to extract time-course absorption and scattering coefficients of the skin tissue, which, through the fitting of lambert's law of absorbance, can be used to determine the concentration of oxygenated/deoxygenated hemoglobin molecules, and consequentially, the oxygen saturation of skin tissue and total hemoglobin (THb) concentration. Expressly, a sudden jump in heartbeat rate at the beginning of the exercise, a temporal lag of the rising edge of skin temperature behind that of the THb concentration in the procession of step-wise incremental working intensity, and the uprising of THb in the exhaustion zone in responses to the physiological adaptation to exercise were identified. Finally, conclusive remarks were drawn that the FD DRS system is useful in extracting the hemodynamic properties of forearm skin which is often being neglected in previous exercise physiology studies by DRS-related techniques. The detailed variation of hemodynamic and optical scattering parameters of forearm skin elucidated in the studies can be applied for the analysis of athletes' physiological status, and may be a potential reference for the design of future wearable devices.

Therapeutic Potential of Hemoglobin Derived from the Marine Worm Arenicola marina (M101): A Literature Review of a Breakthrough Innovation

Oxygen (O₂) is indispensable for aerobic respiration and cellular metabolism. In case of injury, reactive oxygen species are produced, causing oxidative stress, which triggers cell damaging chemical mediators leading to ischemic reperfusion injuries (IRI). Sufficient tissue oxygenation is necessary for optimal wound healing. In this context, several hemoglobin-based oxygen carriers have been developed and tested, especially as graft preservatives for transplant procedures. However, most of the commercially available O₂ carriers increase oxidative stress and show some adverse effects. Interestingly, the hemoglobin derived from the marine lugworm Arenicola marina (M101) has been presented as an efficient therapeutic O₂ carrier with potential anti-inflammatory, anti-bacterial, and antioxidant properties. Furthermore, it has demonstrated promise as a supplement to conventional organ preservatives by reducing IRI. This review summarizes the properties and various applications of M101. M101 is an innovative oxygen carrier with several beneficial therapeutic properties, and further research must be carried out to determine its efficacy in the management of different pathologies.

Effects of impaired microvascular flow regulation on metabolism-perfusion matching and organ function

Impaired tissue oxygen delivery is a major cause of organ damage and failure in critically ill patients, which can occur even when systemic parameters, including cardiac output and arterial hemoglobin saturation, are close to normal. This review addresses oxygen transport mechanisms at the microcirculatory scale, and how hypoxia may occur in spite of adequate convective oxygen supply. The structure of the microcirculation is intrinsically heterogeneous, with wide variations in vessel diameters and flow pathway lengths, and consequently also in blood flow rates and oxygen levels. The dynamic processes of structural adaptation and flow regulation continually adjust microvessel diameters to compensate for heterogeneity, redistributing flow according to metabolic needs to ensure adequate tissue oxygenation. A key role in flow regulation is played by conducted responses, which are generated and propagated by endothelial cells and signal upstream arterioles to dilate in response to local hypoxia. Several pathophysiological conditions can impair local flow regulation, causing hypoxia and tissue damage leading to organ failure. Therapeutic measures targeted to systemic parameters may not address or may even worsen tissue oxygenation at the microvascular level. Restoration of tissue oxygenation in critically ill patients may depend on restoration of endothelial cell function, including conducted responses.

Journal of Clinical Monitoring and Computing 2019 end of year summary: monitoring tissue oxygenation and perfusion and its autoregulation

Tissue perfusion monitoring is increasingly being employed clinically in a non-invasive fashion. In this end-of-year summary of the Journal of Clinical Monitoring and Computing, we take a closer look at the papers published recently on this subject in the journal. Most of these papers focus on monitoring cerebral perfusion (and associated hemodynamics), using either transcranial doppler measurements or near-infrared spectroscopy. Given the importance of cerebral autoregulation in the analyses performed in most of the studies discussed here, this end-of-year summary also includes a short description of cerebral hemodynamic physiology and its autoregulation. Finally, we review articles on somatic tissue oxygenation and its possible association with outcome.

Impact of perioperative hemodynamic optimization therapies in surgical patients: economic study and meta-analysis

Background

Several studies suggest that hemodynamic optimization therapies can reduce complications, the length of hospital stay and costs. However, Brazilian data are scarce. Therefore, the objective of this analysis was to evaluate whether the improvement demonstrated by hemodynamic optimization therapy in surgical patients could result in lower costs from the perspective of the Brazilian public unified health system.

Methods

A meta-analysis was performed comparing surgical patients who underwent hemodynamic optimization therapy (intervention) with patients who underwent standard therapy (control) in terms of complications and hospital costs. The cost-effectiveness analysis evaluated the clinical and financial benefits of hemodynamic optimization protocols for surgical patients. The analysis considered the clinical outcomes of randomized studies published in the last 20 years that involved surgeries and hemodynamic optimization therapy. Indirect costs (equipment depreciation, estate and management activities) were not included in the analysis.

Results

A total of 21 clinical trials with a total of 4872 surgical patients were selected. Comparison of the intervention and control groups showed lower rates of infectious (RR = 0.66; 95% CI = 0.58–0.74), renal (RR = 0.68; 95% CI = 0.54–0.87), and cardiovascular (RR = 0.87; 95% CI = 0.76–0.99) complications and a nonstatistically significant lower rate of respiratory complications (RR = 0.82; 95% CI = 0.67–1.02). There was no difference in mortality (RR = 1.02; 95% CI = 0.80–1.3) between groups. In the analysis of total costs, the intervention group showed a cost reduction of R$396,024.83-BRL ($90,161.38-USD) for every 1000 patients treated compared to the control group. The patients in the intervention group showed greater effectiveness, with 1.0 fewer days in the intensive care unit and hospital. In addition, there were 333 fewer patients with complications, with a consequent reduction of R$1,630,341.47-BRL ($371,173.27-USD) for every 1000 patients treated.

Conclusions

Hemodynamic optimization therapy is cost-effective and would increase the efficiency of and decrease the burden of the Brazilian public health system.

Systematic review and meta-analysis of the perioperative use of vasoactive drugs on postoperative outcomes after major abdominal surgery

BACKGROUND

The perioperative use of vasoactive drugs is ubiquitous in clinical anaesthesia; yet, the drugs, doses, and haemodynamic targets used are highly variable. Our objectives were to determine whether the perioperative administration of vasoactive drugs reduces mortality, morbidity, and length of stay in adult patients (aged 16 yr or older) undergoing major abdominal surgery.

METHODS

MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched for peer-reviewed RCTs with no language or date restrictions. Studies that assessed the intraoperative use of vasoactive drugs were included. Title, abstract, and full-text screening was performed. Risk of bias for each outcome measure was conducted. We calculated the risk ratio (RR) using the Mantel-Haenszel random-effects model with corresponding 95% confidence interval (CI) for dichotomous outcomes, and mean difference using the inverse variance random-effects model with corresponding 95% CI for continuous outcomes.

RESULTS

Twenty-six studies (5561 participants) were included. There was no difference in mortality at the longest follow-up with an RR of 0.84 (95% CI: 0.63-1.12; P=0.23). The intervention significantly reduced the number of patients with one or more postoperative complications; RR: 0.76 (95% CI: 0.66-0.88; P=0.0002). Hospital length of stay was reduced by 0.91 days in the intervention group.

CONCLUSIONS

This review is limited by the quality and sample size of individual studies, and the heterogeneity of the settings, interventions, and outcome measures. Perioperative administration of vasoactive drugs may reduce postoperative complications and hospital length of stay in adult patients having major abdominal surgery.

Randomized controlled trial of regional tissue oxygenation following goal-directed fluid therapy during laparoscopic colorectal surgery

BACKGROUND

A randomized, double-blinded controlled trial was performed to evaluate how perioperative goal-directed fluid therapy (GDFT) influences tissue oxygenation in laparoscopic colorectal surgery.

METHODS

A total of 74 patients undergoing elective laparoscopic colorectal surgery were treated with GDFT (G group) guided by stroke volume variation or conventional fluid therapy (C group). Forearm, crural, and cerebral tissue oxygen saturation (rSO₂) were simultaneously measured by near-infrared spectroscopy. Parameters of hemodynamics and rSO₂ were obtained at seven time points including before induction of anesthesia (T1), 5 min after trachea cannula (T2), 5, 60, and 120 min after pneumoperitoneum in the Trendeleburg position (T3, T4 and T5, respectively), after desufflation in the Trendeleburg position (T6), and at the end of the operation in a supine position (T7). The postoperative outcomes were recorded.

RESULTS

Compared to C group, intraoperatively, patients in the G group received more colloid (P<0.05). The stroke volume variation in G group at T5, T6 and T7 was significantly lower than that in C group (P<0.05). The cardiac index, forearm and crural rSO₂ in G group at T4, T5, T6 and T7 were significantly higher than those in C group (P<0.05). No significant differences were observed for the cerebral rSO₂ between the two groups (P > 0.05). The postoperative hospital stay and complications also showed no differences between these two groups.

CONCLUSIONS

Although the implementation of GDFT cannot increase cerebral rSO₂, the forearm and crural rSO₂ are improved during the laparoscopic colorectal surgery, which is helpful to reduce the risk of regional tissue hypoxia.

Hemodynamic goal-directed therapy and postoperative kidney injury: an updated meta-analysis with trial sequential analysis

Background

Perioperative goal-directed therapy (GDT) reduces the risk of renal injury. However, several questions remain unanswered, such as target, kind of patients and surgery, and role of fluids and inotropes. We therefore update a previous analysis, including all studies published in the meanwhile, to clarify the clinical impact of this strategy on acute kidney injury.

Main body

Randomized controlled trials enrolling adult patients undergoing major surgery were considered. GDT was defined as perioperative monitoring and manipulation of hemodynamic parameters to reach normal or supranormal values by fluids alone or with inotropes. Trials comparing the effects of GDT and standard hemodynamic therapy were considered. Primary outcome was acute kidney injury, whichever definition was used. Meta-analytic techniques (analysis software RevMan, version 5.3) were used to combine studies, using random-effect odds ratios (OR) and 95% confidence intervals (CI). Trial sequential analyses were performed including all trials and considering only low risk of bias trials. Sixty-five trials with an overall sample of 9308 patients were included. OR for the development of renal injury was 0.64 (95% CI, 0.62–0.87; p = 0.0003), with no statistical heterogeneity. Trial sequential analyses and sensitivity analysis including studies with low risk of bias confirmed the main results. A significant decrease in renal injury rate was observed in studies that adopted cardiac output and oxygen delivery as hemodynamic target and that used both fluids and inotropes. The postoperative kidney injury rate was significantly lower in trials enrolling “high-risk” patients and major abdominal and orthopedic surgery.

Short conclusion

The present meta-analysis suggests that targeting GDT to perioperative systemic oxygen delivery, by means of fluids and inotropes, can be the best way to improve renal perfusion and oxygenation in high-risk patients undergoing major abdominal and orthopedic surgery.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2516-4) contains supplementary material, which is available to authorized users.

Recommendations on RBC Transfusion in General Critically Ill Children Based on Hemoglobin and/or Physiologic Thresholds From the Pediatric Critical Care Transfusion and Anemia Expertise Initiative

OBJECTIVES

To present the consensus recommendations and supporting literature for RBC transfusions in general critically ill children from the Pediatric Critical Care Transfusion and Anemia Expertise Initiative.

DESIGN

Consensus conference series of international, multidisciplinary experts in RBC transfusion management of critically ill children.

METHODS

The panel of 38 experts developed evidence-based and, when evidence was lacking, expert-based recommendations and research priorities regarding RBC transfusions in critically ill children. The subgroup on RBC transfusion in general critically ill children included six experts. Electronic searches were conducted using PubMed, EMBASE, and Cochrane Library databases from 1980 to May 30, 2017, using a combination of keywords to define concepts of RBC transfusion and critically ill children. Recommendation consensus was obtained using the Research and Development/UCLA Appropriateness Method. The results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method.

RESULTS

Three adjudicators reviewed 4,399 abstracts; 71 papers were read, and 17 were retained. Three papers were added manually. The general Transfusion and Anemia Expertise Initiative subgroup developed, and all Transfusion and Anemia Expertise Initiative members voted on two good practice statements, six recommendations, and 11 research questions; in all instances, agreement was reached (> 80%). The good practice statements suggest a framework for RBC transfusion in PICU patients. The good practice statements and recommendations focus on hemoglobin as a threshold and/or target. The research questions focus on hemoglobin and physiologic thresholds for RBC transfusion, alternatives, and risk/benefit ratio of transfusion.

CONCLUSIONS

Transfusion and Anemia Expertise Initiative developed pediatric-specific good practice statements and recommendations regarding RBC transfusion management in the general PICU population, as well as recommendations to guide future research priorities. Clinical recommendations emphasized relevant hemoglobin thresholds, and research recommendations emphasized a need for further understanding of physiologic thresholds, alternatives to RBC transfusion, and hemoglobin thresholds in populations with limited pediatric literature.

Association of conflicts of interest with the results and conclusions of goal-directed hemodynamic therapy research: a systematic review with meta-analysis

PURPOSE

The association between conflicts of interest (COI) and study results or article conclusions in goal-directed hemodynamic therapy (GDHT) research is unknown.

METHODS

Randomized controlled trials comparing GDHT with usual care were identified. COI were classified as industry sponsorship, author conflict, device loaner, none, or not reported. The association between COI and study results (complications and mortality) was assessed using both stratified meta-analysis and mixed effects meta-regression. The association between COI and an article's conclusion (graded as GDHT-favorable, neutral, or unfavorable) was investigated using logistic regression.

RESULTS

Of the 82 eligible articles, 43 (53%) had self-reported COI, and 50 (61%) favored GDHT. GDHT significantly reduced complications on the basis of the meta-analysis of studies with any type of COI, studies declaring no COI, industry-sponsored studies, and studies with author conflict but not on studies with a device loaner. However, no significant relationship between COI and the relative risk (GDHT vs. usual care) of developing complications was found on the basis of meta-regression (p = 0.25). No significant effect of GDHT was found on mortality. COI had a significant overall effect (p = 0.016) on the odds of having a GDHT-favorable vs. neutral conclusion based on 81 studies. Eighty-four percent of the industry-sponsored studies had a GDHT-favorable conclusion, while only 27% of the studies with a device loaner had the same conclusion grade.

CONCLUSIONS

The available evidence does not suggest a close relationship between COI and study results in GDHT research. However, a potential association may exist between COI and an article's conclusion in GDHT research.

Transfusion Decision Making in Pediatric Critical Illness

Transfusion decision making (TDM) in the critically ill requires consideration of: (1) anemia tolerance, which is linked to active pathology and to physiologic reserve, (2) differences in donor RBC physiology from that of native RBCs, and (3) relative risk from anemia-attributable oxygen delivery failure vs hazards of transfusion, itself. Current approaches to TDM (e.g. hemoglobin thresholds) do not: (1) differentiate between patients with similar anemia, but dissimilar pathology/physiology, and (2) guide transfusion timing and amount to efficacy-based goals (other than resolution of hemoglobin thresholds). Here, we explore approaches to TDM that address the above gaps.

Intraoperative modifiable risk factors of colorectal anastomotic leakage: Why surgeons and anesthesiologists should act together

BACKGROUND

Colorectal anastomotic leakage (CAL) is a major surgical complication in intestinal surgery. Despite many optimizations in patient care, the incidence of CAL is stable (3-19%) [1]. Previous research mainly focused on determining patient and surgery related risk factors. Intraoperative non-surgery related risk factors for anastomotic healing also contribute to surgical outcome. This review offers an overview of potential modifiable risk factors that may play a role during the operation.

METHODS

Two independent literature searches were performed using EMBASE, Pubmed and Cochrane databases. Both clinical and experimental studies published in English from 1985 to August 2015 were included. The main outcome measure was the risk of anastomotic leakage and other postoperative complications during colorectal surgery. Determined risk factors of CAL were stated as strong evidence (level I and II high quality studies), and potential risk factors as either moderate evidence (experimental studies level III), or weak evidence (level IV or V studies).

RESULTS

The final analysis included 117 articles. Independent factors of CAL are diabetes mellitus, hyperglycemia and a high HbA1c, anemia, blood loss, blood transfusions, prolonged operating time, intraoperative events and contamination and a lack of antibiotics. Unequivocal are data on blood pressure, the use of inotropes/vasopressors, oxygen suppletion, type of analgesia and goal directed fluid therapy. No studies could be found identifying the impact of body core temperature or mean arterial pressure on CAL. Subjective factors such as the surgeons' own assessment of local perfusion and visibility of the operating field have not been the subject of relevant studies for occurrence in patients with CAL.

CONCLUSION

Both surgery related and non-surgery related risk factors that can be modified must be identified to improve colorectal care. Surgeons and anesthesiologists should cooperate on these items in their continuous effort to reduce the number of CAL. A registration study determining individual intraoperative risk factors of CAL is currently performed as a multicenter cohort study in the Netherlands.

The prognostic value of muscle regional oxygen saturation index in severe community-acquired pneumonia: a prospective observational study

Background

Community-acquired pneumonia (CAP) mortality exceeds 20 % in critical care patients despite appropriate antibiotic therapy. Regional tissue oxygen saturation index (rSO2) measured with near-infrared spectroscopy (NIRS) might facilitate early detection for patients at risk of serious complications. Our objectives were to determine the relationship between early determination of rSO2 and mortality and to compare discrimination power for mortality of rSO2 and other resuscitation variables in critically ill CAP patients.

Methods

This is a prospective observational study. Patients with CAP were enrolled within 6 h to intensive care admission. Demographics and clinical variables were recorded. rSO2 was determined using NIRS in brachioradialis muscle. All variables were determined at baseline and 24 h after admission.

Results

Forty patients were enrolled. Fourteen patients (35 %) had a baseline rSO2 < 60 % and 7 of them died (50 %). Only 1 of 26 (3.8 %) patients with rSO2 ≥ 60 % died (p = 0.007). The area under ROC curve (AUROC) showed consistent mortality discrimination at baseline (0.84, p = 0.03) and at 24 h (0.86, p = 0.006) for rSO2 values. Cox regression analysis showed that “low” rSO2 at ICU admission (hazard ratio (HR) = 8.99; 95 % confidence interval (CI) 1.05–76.8; p = 0.045) and “low” rSO2 at 24 h (HR = 13.18; 95 % CI 1.52–113.6; p = 0.019) were variables independently associated with mortality. In contrast, other variables such as Acute Physiology and Chronic Health Evaluation (APACHE II) score (HR = 1.09; 95 % CI 0.99–1.19; p = 0.052) were not associated with mortality.

Conclusions

Our findings suggest that forearm skeletal muscle rSO2 differs in patients with severe CAP according to outcome and might be an early prognosis tool.