Impact of emergency intubation on central venous oxygen saturation in critically ill patients: a multicenter observational study

INTRODUCTION

Central venous oxygen saturation (ScvO2) has emerged as an important resuscitation goal for critically ill patients. Nevertheless, growing concerns about its limitations as a perfusion parameter have been expressed recently, including the uncommon finding of low ScvO2 values in patients in the intensive care unit (ICU). Emergency intubation may induce strong and eventually divergent effects on the physiologic determinants of oxygen transport (DO2) and oxygen consumption (VO2) and, thus, on ScvO2. Therefore, we conducted a study to determine the impact of emergency intubation on ScvO2.

METHODS

In this prospective multicenter observational study, we included 103 septic and non-septic patients with a central venous catheter in place and in whom emergency intubation was required. A common intubation protocol was used and we evaluated several parameters including ScvO2 before and 15 minutes after emergency intubation. Statistical analysis included chi-square test and t test.

RESULTS

ScvO2 increased from 61.8 +/- 12.6% to 68.9 +/- 12.2%, with no difference between septic and non-septic patients. ScvO2 increased in 84 patients (81.6%) without correlation to changes in arterial oxygen saturation (SaO2). Seventy eight (75.7%) patients were intubated with ScvO2 less than 70% and 21 (26.9%) normalized the parameter after the intervention. Only patients with pre-intubation ScvO2 more than 70% failed to increase the parameter after intubation.

CONCLUSIONS

ScvO2 increases significantly in response to emergency intubation in the majority of septic and non-septic patients. When interpreting ScvO2 during early resuscitation, it is crucial to consider whether the patient has been recently intubated or is spontaneously breathing.

Minimally invasive cardiac output monitoring in the perioperative setting

With advancing age and increased co-morbidities in patients, the need for monitoring devices during the perioperative period that allow clinicians to track physiologic variables, such as cardiac output (CO), fluid responsiveness and tissue perfusion, is increasing. Until recently, the only tool available to anesthesiologists to monitor CO was either a pulmonary artery catheter or transesophageal echocardiograph. These devices have their limitations and potential for morbidity. Several new devices (including esophageal Doppler monitors, pulse contour analysis, indicator dilution, thoracic bioimpedance and partial non-rebreathing systems) have recently been marketed which have the ability to monitor CO noninvasively and, in some cases, assess the patient's ability to respond to fluid challenges. In this review, we will describe these new devices including the technology, studies on their efficacy and the limitations of their use.

Separate origin of left anterior descending artery and left circumflex artery from left aortic sinus of Valsalva: visualization by multislice computed tomography before and after coronary artery bypass graft

A 59-year-old woman was admitted to our hospital because of atypical chest pain. Stress ECG test was inconclusive. The patient underwent contrast-enhanced 16-slice computed tomography which demonstrated the absence of left main, and separate but adjacent ostia of the left anterior descending artery (LAD) and the left circumflex artery (CX) from the left coronary aortic sinus of Valsalva and severe narrowing of their proximal tracts. Conventional coronary angiography confirmed the diagnosis. Some time later, the patient underwent coronary artery bypass graft by left internal mammary artery graft to the LAD and Y-saphenous vein bypass to the obtuse marginal branch of CX. Multislice computed tomography (MSCT) scan, 1 year later, revealed the patency of grafts. MSCT, with the aid of postprocessing techniques, is an accurate and precise, noninvasive tool for the visualization of coronary artery anatomy, identification of coronary stenoses and evaluation of coronary artery bypass grafts.

Increased mortality, morbidity, and cost associated with red blood cell transfusion after cardiac surgery

PURPOSE OF REVIEW

Literature since 2006 was reviewed to identify the harms and costs of red blood cell (RBC) transfusion.

RECENT FINDINGS

Several studies, in people having various cardiac surgery operations, found strong associations of RBC transfusion with mortality and postoperative morbidity. The effect on mortality was strongest close to the time of operation but extended to 5 years. Morbidity outcomes included serious wound and systemic infections, renal failure, prolonged ventilation, low cardiac index, myocardial infarction, and stroke. RBC transfusion was also strongly associated with increased cardiac intensive care unit and ward postoperative stay, and hence, increased cost of admission; available studies did not consider all resources used and the associated costs.

SUMMARY

The harms of RBC transfusion have potentially serious and long-term consequences for patients and are costly for health services. This evidence should shift clinicians' equipoise towards more restrictive transfusion practice. The immediate aim should be to avoid transfusing a small number of RBC units for general malaise attributed to anaemia, a practice that appears to occur in about 50% of transfused patients. Randomized trials comparing restrictive and liberal transfusion triggers are urgently needed to directly compare the benefits and harms from RBC transfusion.

Noninvasive cardiac output determination: broadening the applicability of hemodynamic monitoring

Although cardiac output (CO) monitoring is usually only used in intensive care units (ICUs) and operating rooms, there is increasing evidence that CO should be determined and optimized as early as possible, even before admission to the ICU, in the care of hemodynamically compromised patients. A variety of different minimally or noninvasive CO determination techniques have been developed, but not all of them are suitable for early hemodynamic monitoring outside the ICU. In this review, the different available methods for CO monitoring are presented and their potential for early hemodynamic assessment is discussed.

Impact of obesity on perioperative morbidity and mortality after pancreaticoduodenectomy

BACKGROUND

Obesity has been implicated as a risk factor for perioperative and postoperative complications. The aim of this study was to determine the impact of obesity on morbidity and mortality in patients undergoing pancreaticoduodenectomy (PD).

STUDY DESIGN

Between January 2000 and July 2007, 262 patients underwent PD at Thomas Jefferson University Hospital, of whom 240 had complete data, including body mass index (BMI; calculated as kg/m(2)) for analysis. Data on BMI, preoperative parameters, operative details, and postoperative course were collected. Patients were categorized as obese (BMI >or= 30), overweight (BMI >or= 25 and < 30), or normal weight (BMI < 25). Complications were graded according to previously published scales. Other end points included length of postoperative hospital stay, blood loss, and operative duration. Analyses were performed using univariate and multivariable models.

RESULTS

There were 103 (42.9%) normal-weight, 71 (29.6%) overweight, and 66 (27.5%) obese patients. There were 5 perioperative deaths (2.1%), with no differences across BMI categories. A significant difference in median operative duration and blood loss between obese and normal-weight patients was identified (439 versus 362.5 minutes, p = 0.0004; 650 versus 500 mL, p = 0.0139). In addition, median length of stay was significantly longer for BMI (9.5 versus 8 days, p = 0.095). Although there were no significant differences in superficial wound infections, obese patients did have an increased rate of serious complications compared with normal-weight patients (24.2% versus 13.6%, respectively; p = 0.10).

CONCLUSIONS

Obese patients undergoing PD have a substantially increased blood loss and longer operative time but do not have a substantially increased length of postoperative hospital stay or rate of serious complications. These findings should be considered when assessing patients for operation and when counseling patients about operative risk, but they do not preclude obese individuals from undergoing definitive pancreatic operations.

Complications relating to perfusion and extracorporeal circulation associated with the treatment of patients with congenital cardiac disease: consensus definitions from the Multi-Societal Database Committee for Pediatric and Congenital Heart Disease

The International Consortium for Evidence-Based Perfusion (www.bestpracticeperfusion.org) is a collaborative partnership of societies of perfusionists, professional medical societies, and interested clinicians, whose aim is to promote the continuous improvement of the delivery of care and outcomes for patients undergoing extracorporeal circulation. Despite the many advances made throughout the history of cardiopulmonary bypass, significant variation in practice and potential for complication remains. To help address this issue, the International Consortium for Evidence-Based Perfusion has joined the Multi-Societal Database Committee for Pediatric and Congenital Heart Disease to develop a list of complications in congenital cardiac surgery related to extracorporeal circulation conducted via cardiopulmonary bypass, extracorporeal membrane oxygenation, or mechanical circulatory support devices, which include ventricular assist devices and intra-aortic balloon pumps. Understanding and defining the complications that may occur related to extracorporeal circulation in congenital patients is requisite for assessing and subsequently improving the care provided to the patients we serve. The aim of this manuscript is to identify and define the myriad of complications directly related to the extracorporeal circulation of congenital patients.

Device-associated nosocomial infections in limited-resources countries: findings of the International Nosocomial Infection Control Consortium (INICC)

NEED

The rates of health care-associated infections (HAIs) and bacterial resistance in developing countries are 3 to 5 times higher than international standards. HAIs increase length of stay (10 days), costs (US $5000 to US $12,000), and mortality (by a factor of 2 to 3).

ORGANIZATION

The International Nosocomial Infection Control Consortium (INICC), founded in 1998, is the only source of aggregated international data on the epidemiology of device-associated infections (DAIs). Its advisory board includes 12 representatives from developed countries, who help guide INICC's activities, and 8 country coordinators. The INICC network has about 5400 active researchers in 98 intensive care units (ICUs) in 18 countries on 4 continents that conduct infection control research and surveillance using standardized DAI surveillance definitions and methodologies.

SURVEILLANCE

Participating hospitals use the Centers for Disease Control and Prevention (CDC) surveillance method and DAI definitions. Unlike the CDC, the INICC collects data from patients with and without DAI and matches patients to evaluate risk factors, attributable mortality, length of stay, and costs and conducts process surveillance to measure and improve compliance with infection control guidelines.

RESULTS

INICC's surveillance at 98 ICUs in 18 limited resources countries on 4 continents for 10 years has significantly improved infection control guidelines compliance and reduced DAI rates and mortality rates. After 11 years of implementing process surveillance intervention in 77 ICUs of 34 cities of 14 countries, including observation of 88,661 opportunities for hand hygiene, education, performance monitoring, feedback, and peer support from high-level hospital administrators, hand-hygiene compliance among ICU healthcare workers increased from 35.1% to 60.7% (RR 1.73, P < 0.01). In 78 ICUs of 37 cities of 13 countries, by implementing outcome and process surveillance interventions, INICC reduced central line associated bloodstream infection (CLAB) rates from 16.1 to 10.1 CLABs per 1000 CL days (RR: 0.63, P < 0.01), ventilator associated pneumonia (VAP) from 22.5 to 18.6 VAPs per1000 device days (RR: 0.83, P < 0.01), and catheter associated urinary tract infections (CAUTI) rates from 8.2 to 6.9 CAUTIs per 1000 device days (RR: 0.85, P = 0.02).

CONCLUSION

Implementation of INICC outcome and process surveillance, education, monitoring and performance feedback methodologies increases compliance with hand hygiene and other infection-control interventions and reduces rates of DAIs.

Therapeutic targets in pulmonary arterial hypertension

Pulmonary arterial hypertension is a progressive, fatal disease. Current treatments including prostanoids, endothelin-1 (ET-1) antagonists, and phosphodiesterase (PDE) inhibitors, have sought to address the pulmonary vascular endothelial dysfunction and vasoconstriction associated with the condition. These treatments may slow the progression of the disease but do not afford a cure. Future treatments must target more directly the structural vascular changes that impair blood flow through the pulmonary circulation. Several novel therapeutic targets have been proposed and are under active investigation, including soluble guanylyl cyclase, phosphodiesterases, tetrahydrobiopterin, 5-HT2B receptors, vasoactive intestinal peptide, receptor tyrosine kinases, adrenomedullin, Rho kinase, elastases, endogenous steroids, endothelial progenitor cells, immune cells, bone morphogenetic protein and its receptors, potassium channels, metabolic pathways, and nuclear factor of activated T cells. Tyrosine kinase inhibitors, statins, 5-HT2B receptor antagonists, EPCs and soluble guanylyl cyclase activators are among the most advanced, having produced encouraging results in animal models, and human trials are underway. This review summarises the current research in this area and speculates on their likely success.

Correlation between central venous oxygen saturation and oxygen delivery changes following fluid therapy

BACKGROUND

The rationale for using central venous oxygen saturation (ScvO(2)) in various clinical scenarios is that it reflects the balance between oxygen delivery (DO(2)) and demands. In this study, we evaluated the correlation between ScvO(2) and DO(2) changes (Delta Do(2), DeltaScvO(2)) in patients receiving fluid therapy following coronary surgery. We also correlated the changes of mean arterial pressure (Delta MAP) and central venous pressure (Delta CVP), with Delta DO(2).

METHODS

Sixty consecutive sedated and mechanically ventilated adult patients, with cardiac index <or=2.3 L/min/m(2) and a pulmonary artery occlusion pressure <or=12 mmHg following coronary surgery, were included. Concomitant hemodynamic parameters, arterial and venous blood gases were measured before (T0) and after (T1) administration of a 500 ml bolus of an isotonic crystalloid solution over 30 min. The correlations between Delta DO(2) and DeltaScvO(2), Delta MAP or Delta CVP were evaluated by linear regression analysis and Pearson test.

RESULTS

Cardiac index (1.9+/-0.2 vs 2.3+/-0.5 ml/min/m(2)), MAP (83+/-11 vs 94+/-13 mm Hg) and CVP (5.7+/-3 vs 7.1+/-3 mmHg) were significantly higher at T1 compared with T0. The correlation of Delta DO(2) with DeltaScvO(2) was positive, significant (r=0.41; P=0.004) and superior to its correlation with Delta MAP (r=0.30; P=0.01) or Delta CVP (r=0.03; P=0.78).

CONCLUSION

A significant correlation between ScvO(2) and DO(2) changes was found in patients receiving fluid therapy following coronary surgery. ScvO(2) could be used as an indicator to track DO(2) and to guide volume loading.

[Tako-Tsubo syndrome after anaphylaxis caused by succinylcholine during general anaesthesia]

The Tako-Tsubo syndrome (or transient left ventricular apical balloning) is a new clinical entity, very similar to acute myocardial infarction, but different by its excellent short-term prognosis. It has been reported after a physical or an emotional stress, and it is diagnosed by a coronary angiogram and a left ventriculography. We report here a case of Tako-Tsubo syndrome related to an anaphylactic shock caused by succinylcholine during general anaesthesia of a female patient, wearing an unadjustable gastric band.

Analysis of N-terminal pro-B-type natriuretic peptide and cardiac index in multiple injured patients: a prospective cohort study

Introduction

Increased serum B-type natriuretic peptide (BNP) has been identified for diagnosis and prognosis of impaired cardiac function in patients suffering from congestive heart failure, ischemic heart disease, and sepsis. However, the prognostic value of BNP in multiple injured patients developing multiple organ dysfunction syndrome (MODS) remains undetermined. Therefore, the aims of this study were to assess N-terminal pro-BNP (NT-proBNP) in multiple injured patients and to correlate the results with invasively assessed cardiac output and clinical signs of MODS.

Methods

Twenty-six multiple injured patients presenting a New Injury Severity Score of greater than 16 points were included. The MODS score was calculated on admission as well as 24, 48, and 72 hours after injury. Patients were subdivided into groups: group A showed minor signs of organ dysfunction (MODS score less than or equal to 4 points) and group B suffered from major organ dysfunction (MODS score of greater than 4 points). Venous blood (5 mL) was collected after admission and 6, 12, 24, 48, and 72 hours after injury. NT-proBNP was determined using the Elecsys proBNP^® assay. The hemodynamic monitoring of cardiac index (CI) was performed using transpulmonary thermodilution.

Results

Serum NT-proBNP levels were elevated in all 26 patients. At admission, the serum NT-proBNP values were 116 ± 21 pg/mL in group A versus 209 ± 93 pg/mL in group B. NT-proBNP was significantly lower at all subsequent time points in group A in comparison with group B (P < 0.001). In contrast, the CI in group A was significantly higher than in group B at all time points (P < 0.001). Concerning MODS score and CI at 24, 48, and 72 hours after injury, an inverse correlation was found (r = -0.664, P < 0.001). Furthermore, a correlation was found comparing MODS score and serum NT-proBNP levels (r = 0.75, P < 0.0001).

Conclusions

Serum NT-proBNP levels significantly correlate with clinical signs of MODS 24 hours after multiple injury. Furthermore, a distinct correlation of serum NT-proBNP and decreased CI was found. The data of this pilot study may indicate a potential value of NT-proBNP in the diagnosis of post-traumatic cardiac impairment. However, further studies are needed to elucidate this issue.

Physiological changes of pregnancy and monitoring

Advances in medical care have led to increasing numbers of complex, high-risk obstetric patients. Specialist training and a sound knowledge of normal maternal physiology are essential to optimize outcomes. One of the earliest observed changes is peripheral vasodilatation; this causes a fall in systemic vascular resistance and triggers physiological changes in the cardiovascular and renal systems, with 40-50% increases in cardiac output and glomerular filtration rates. Safety concerns over Swan Ganz catheters have driven the increasing interest in alternative techniques, such as echocardiography, thoracic bioimpedance and pulse contour analysis, although their exact roles in future obstetric high-dependency care have yet to be established. Analysis of arterial blood gases is fundamental to the management of sick patients, and correct interpretation can be aided by a systematic approach. Observation charts are almost ubiquitous in all aspects of medicine, but little evidence exists to support their use in the high-dependency setting.

Roles of Oxidants, Nitric Oxide, and Asymmetric Dimethylarginine in Endothelial Function

Vascular endothelium plays a crucial role in ensuring normal function and morphology of blood vessels, and many risk factors of atherosclerosis act via their effects on endothelial cells. However, endothelial dysfunction is induced by very different pathomechanisms. In principle, it is caused by an impaired bioavailability of nitric oxide (NO) due to an inhibited synthesis (eg, by asymmetric dimethylarginine [ADMA]) or increased consumption of formed NO (by reactive oxygen species [ROS]). ROS can be synthesized in the organism (eg, by different enzymes) or can be administered from the environment (eg, by cigarette smoking), whereas ADMA is the subject of endogenous metabolism only. Many studies have elucidated the system of pathomechanisms and targeted some as potential goals for therapeutic interventions. This review demonstrates roles of ROS, NO, ADMA, endothelin, and estrogen in endothelial function and dysfunction focusing on homocysteinemia and diabetes mellitus and provide examples for the medical treatment of endothelial dysfunction.

Inter-rater reliability for noninvasive measurement of cardiac function in children

INTRODUCTION

A transcutaneous ultrasound monitor has recently been developed which noninvasively and quickly measures cardiac output. Validity and reliability testing has been reported in adults. No reliability testing has been undertaken in the pediatric population.

OBJECTIVE

Our objective was to evaluate the inter-rater reliability of a transcutaneous Doppler ultrasound technique to measure cardiac index (CI) and stroke volume index (SVI) in pediatric emergency department patients.

METHODS

An 8-month prospective observational study was conducted on a convenience sample of emergency department patients younger than 18 years old. Five raters were trained to use an ultrasound cardiac output monitoring device. Two raters, blinded to each other's results, obtained independent measurements from the same patient within 15 minutes of each other. Inter-rater agreement was measured with the Pearson product correlation coefficient. Bland-Altman analysis demonstrated the extent of deviation from a line of agreement between raters.

RESULTS

Ninety-seven patients were enrolled. Major diagnostic categories included infection, trauma, and gastrointestinal disorders. There was significant inter-rater correlation for CI (r = 0.76; 95% confidence interval, 0.66Y0.83; P G 0.0001) and SVI (r = 0.79; 95% confidence interval, 0.70Y0.86; P G 0.0001). Bland-Altman analysis of CI measurements between 2 raters showed bias of 0.06, SD of bias 1.00, and 95% limits of agreement j1.91 to 2.02 L/min/m2. Stroke volume index showed bias of j0.5, SD of bias 11.01, and 95% limits of agreement j22.08 to 21.08 mL/m2.

CONCLUSIONS

Transcutaneous Doppler ultrasound technique demonstrates acceptable inter-rater agreement for measuring CI and SVI in children.

Review article: Non-invasive assessment of cardiac output with portable continuous-wave Doppler ultrasound

Cardiac output is considered an important parameter when assessing the cardiovascular status of a critically ill patient. Both non-invasive (e.g. bioimpedance, echocardiography) and invasive methods (Swan Ganz catheter) have been used to measure cardiac output. The ultrasonic cardiac output monitoring device provides a new method of non-invasively assessing cardiac output in various clinical settings. The ultrasonic cardiac output monitoring device was introduced clinically in 2001, and appears to be a promising adjunct in the assessment of the cardiovascular state in a variety of patient cohorts. In this short review article, we will introduce this new technique, discuss the required skills and compare it with methods already in use. In particular, a critical comparison with the 'gold standard', the invasive measurement of cardiac output with the pulmonary artery catheter, will be given.

Bispectral index for improving anaesthetic delivery and postoperative recovery

BACKGROUND

The use of clinical signs may not be reliable to measure the hypnotic component of anaesthesia. The use of bispectral index to guide the dose of anaesthetics may have certain advantages over clinical signs.

OBJECTIVES

The objective of this review was to assess whether bispectral index (BIS) reduced anaesthetic use, recovery times, recall awareness and cost.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 2), MEDLINE (1990 to May 2007), EMBASE (1990 to May 2007) and reference lists of articles.

SELECTION CRITERIA

We included randomized controlled trials comparing BIS with clinical signs (CS) in titrating anaesthetic agents.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality, extracted data and analysed the data. We contacted study authors for further details.

MAIN RESULTS

We included 20 studies with 4056 participants. Seven recent trials are still awaiting assessment. BIS-guided anaesthesia reduced the requirement for propofol by 1.30 mg/kg/hr (578 participants; 95% confidence interval (CI) -1.97 to -0.62) and for volatile anaesthetics (desflurane, sevoflurane, isoflurane) by 0.17 minimal alveolar concentration equivalents (MAC) (689 participants; 95% CI -0.27 to -0.07). Irrespective of the anaesthetic, BIS reduced the recovery times: time for eye opening by 2.43 min (996 participants; 95% CI -3.60 to -1.27), response to verbal command by 2.28 min (717 participants; 95% CI -3.47 to -1.09), time to extubation by 3.05 min (1057 participants; 95% CI -3.98 to -2.11) and orientation by 2.46 min (316 participants; 95% CI -3.21 to -1.71). BIS shortened the duration of postanaesthesia care unit stay by 6.83 min (584 participants; 95% CI -12.08 to -1.58) but did not reduce time to home readiness (329 participants; 95% CI -30.11 to 16.09). The BIS-guided anaesthesia significantly reduced the incidence of intraoperative recall awareness in surgical patients with high risk of awareness (OR 0.20, 95% CI 0.05 to 0.79).

AUTHORS' CONCLUSIONS

Anaesthesia guided by BIS within the recommended range (40 to 60) could improve anaesthetic delivery and postoperative recovery from relatively deep anaesthesia. In addition, BIS-guided anaesthesia has a significant impact on reduction of the incidence of intraoperative recall in surgical patients with high risk of awareness.