Defining goals of resuscitation in the critically ill patient

Echocardiographic indicators of fluid responsiveness in hospitalized dogs with compromised hemodynamics and tissue hypoperfusion

OBJECTIVE

To evaluate the accuracy of selected echocardiographic variables used to predict fluid responsiveness in hospitalized dogs with compromised hemodynamics and tissue hypoperfusion.

DESIGN

Diagnostic test study in a prospective cohort of hospitalized dogs.

SETTING

Veterinary referral clinics.

ANIMALS

Forty-four hospitalized dogs with compromised hemodynamics and tissue hypoperfusion were utilized in this study.

INTERVENTIONS

Echocardiographic examination before and after fluid replacement with 30 ml/kg of lactated Ringer's solution.

MEASUREMENTS AND MAIN RESULTS

Pre-fluid replacement measurements of velocity of transmitral E wave (E-peak), the left ventricular end-diastolic internal diameter normalized to body weight (LVIDdN), and the left ventricular end-systolic internal diameter normalized to body weight (LVIDsN) were significantly lower in fluid-responsive patients compared with nonresponders (P < 0.001). The area under the receiver operating characteristic curve (AUROC) with its 95% confidence interval (CI) for each significant predictor was as follows: E-peak 0.907 (0.776-1.000, P < 0.001) and LVIDdN 0.919 (0.801-1.000, P < 0.001). The predictive capacity of LVIDsN was not significantly better than chance (AUROC, 0.753; 95% CI, 0.472-1.000, P = 0.078). A significant negative linear correlation was observed between the percentage of increase in velocity-time integral after expansion and the echocardiographic variables LVIDdN (r_s  = -0.452, P = 0.023) and E-peak (r_s  = -0.396, P = 0.008) pre-fluid replacement. The intraobserver and interobserver variability was very low (<5 %) for all measurements.

CONCLUSIONS

In this study using critically ill dogs with compromised hemodynamics and tissue hypoperfusion, pre-fluid replacement measurements of LVIDdN and E-peak adequately predict fluid responsiveness. Because a small number of fluid nonresponders were involved in the present study (11.4%), further studies that include larger numbers of fluid-nonresponsive animals are required.

A survey of emergency and critical care veterinarians regarding IV fluid bolus therapy and monitoring practices in small animals

OBJECTIVE

To determine how veterinary emergency and critical care clinicians define IV fluid bolus therapy (FBT) and what constitutes a positive response to a fluid bolus.

DESIGN

Online survey of 222 emergency and critical care veterinarians between December 17, 2018, and March 1, 2019.

INTERVENTIONS

An online survey was provided to diplomates of the American College of Veterinary Emergency and Critical Care (ACVECC), residents of ACVECC-approved training programs, as well as house officers and emergency clinicians of a corporate multicenter emergency and specialty care veterinary hospital. The survey investigated the administration of various crystalloid, colloid, and blood products for FBT, as well as expected physiological responses.

MEASUREMENTS AND MAIN RESULTS

The majority of respondents considered balanced isotonic crystalloids appropriate for FBT (220/222 [99.1%]). Respondents showed greater variability in acceptance of 0.9% sodium chloride (105/222 [47.30%]), hypertonic (3-7%) sodium chloride (131/222 [59.01%]), and hydroxyethyl starch solutions (90/222 [40.54%]). Most respondents did not consider physiological plasma (44/222 [19.82%]) an appropriate choice. The most commonly used parameters for monitoring FBT responses were heart rate (220/222 [99.10%]), blood pressure (217/222 [97.75%]), capillary refill time (192/222 [86.49%]), lactate (181/222 [81.53%]), pulse pressure (151/222 [68.02%]), and rectal temperature (145/222 [65.32%]). The majority of respondents perceived that 0-20% (165/222 [74.32%]) of hypotensive patients are nonresponsive to FBT.

CONCLUSIONS

Small animal emergency and critical care clinicians favored balanced isotonic electrolyte solutions and hypertonic sodium chloride solutions for FBT over other options. When monitoring responses to FBT, heart rate, blood pressure, capillary refill time, and plasma lactate were among the most commonly monitored parameters, and there was a lack of familiarity with others. Despite the widespread use of FBT, these findings outline the need for further prospective clinical trials regarding the ideal fluid type and rate, as well as the appropriate responses to FBT.

Intestinal thromboangiitis obliterans: a case report

Background

Thromboangiitis obliterans or Buerger’s disease is a form of peripheral vascular disease in young male smokers. The involvement of the intestine occurs in only about 2% of the cases, when they may present as acute abdomen due to mesenteric ischemia. The uncommonness of the condition makes it a less suspected differential diagnosis, leading to a delay in appropriate management, thereby increasing chances of morbidity or mortality. Cessation of smoking is known to stall the disease progression including visceral involvement, but may not always be the case as happened in the case being presented.

Case presentation

Our Indian Hindu male patient, a known smoker, presented with diffuse abdominal pain along with bouts of vomiting and loose motions. He had a prior history of amputation of the right foot, 4 years before. At presentation he had abdominal distension with diffuse tenderness and guarding. An omental band attached to the tip of the appendix was discovered at the initial exploration along with dilated proximal bowel loops, for which a release of the omental band along with appendectomy was done. He developed an enterocutaneous fistula on the 6th postoperative day for which he had to be reexplored, and multiple jejunal perforations were found. Segmental jejunal resection and a Roux-en-Y gastrojejunostomy with distal ileostomy were done along with a feeding jejunostomy. The patient however again had feculent discharge from the wound for which a third exploration was done. The gastrojejunostomy and feeding jejunostomy sites were leaky, both of which were repaired primarily. The patient developed septicemia which progressed to refractory septic shock, and he ultimately succumbed to his illness on the 23rd postoperative day of the index surgery.

Conclusion

Acute abdomen in a young man who is a chronic smoker and having an antecedent history of amputation of some part of an extremity for a nontraumatic cause should raise the suspicion of Buerger’s disease of the intestine. Although it is a progressive disease and the situation has already progressed by the time intestinal symptoms manifest, early detection may give some scope of salvage and decrease the morbidity and mortality.

Caudal vena cava collapsibility index as a tool to predict fluid responsiveness in dogs

OBJECTIVE

To evaluate the use of the caudal vena cava collapsibility index (CVCCI) as a predictor of fluid responsiveness in hospitalized, critically ill dogs with hemodynamic or tissue perfusion abnormalities.

DESIGN

Retrospective observational study.

SETTING

Private referral center.

ANIMALS

Twenty-seven critically ill, spontaneously breathing dogs with compromised hemodynamics or tissue hypoperfusion.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The electronic medical records were searched for dogs admitted for any cause, from August 2016 to December 2017. We included dogs with ultrasound measurements of: CVCCI, performed at baseline; and velocity time integral (VTI) of the subaortic blood flow, carried out before and after a fluid load. CVCCI was estimated as: (maximum diameter-minimum diameter/maximum diameter) × 100. Dogs in which VTI increased ≥15% were considered fluid responders. The CVCCI accurately predicted fluid responsiveness with an area under the receiver operating characteristic curve of 0.96 (95% CI, 0.88 to 1.00). The optimal cut-off of CVCCI that better discriminated between fluid responders and nonresponders was 27%, with 100.0% sensitivity and 83.3% specificity. At baseline, fluid responders had lower VTI (5.48 [4.26 to 7.40] vs 10.61 [7.38 to 13.23] cm, P = 0.004) than nonresponders. The basal maximum diameter of the caudal vena cava adjusted to body weight was not different between responders and nonresponders (0.050 [0.030 to 0.100] vs 0.079 [0.067 to 0.140] cm/kg, P = 0.339). The increase in VTI was related to basal CVCCI (R = 0.60, P = 0.001). Bland-Altman analysis showed narrow 95% limits of agreement between measurements of CVCCI and VTI performed by different observers or by the same observer.

CONCLUSIONS

The results of this small cohort study suggest that CVCCI can accurately predict fluid responsiveness in critically ill dogs with perfusion abnormalities. Further research is necessary to extrapolate these results to larger populations of hospitalized dogs.

Local Intra-arterial Vasodilator Infusion in Non-Occlusive Mesenteric Ischemia Significantly Increases Survival Rate

Purpose

To investigate the outcome of local intra-arterial papaverine infusion therapy in patients with non-occlusive mesenteric ischemia (NOMI), and factors influencing survival, in comparison with a conservative approach.

Methods

From 2013 to 2019, patients with NOMI confirmed by imaging were included in a retrospective two-center study. According to different in-house standard procedures, patients were treated in each center either conservatively or interventionally by a standardized local infusion of intra-arterial papaverine into the splanchnic arteries. Thirty-day mortality and factors influencing the outcome, such as different demographics and laboratories, were compared between groups using Kaplan–Meier survival analysis and Cox regression, respectively.

Results

A total of 66 patients with NOMI were included, with n = 35 treated interventionally (21 males, mean age 67.7 ± 12.3 years) and n = 31 treated conservatively (18 females, mean age 71.6 ± 9.6 years). There was a significant difference in 30-day mortality between the interventional (65.7%; 12/35 survived) and the conservative group (96.8%; 1/31 survived) (hazard ratio 2.44; P = 0.005). Thresholds associated with a worse outcome of interventional therapy are > 7.68 mmol/l for lactate, < 7.31 for pH and <  − 4.55 for base excess.

Conclusion

Local intra-arterial papaverine infusion therapy in patients with NOMI significantly increases survival rate in comparison with conservative treatment. High lactate levels, low pH and high base excess, and high demand for catecholamines are associated with a poor outcome.

Level of Evidence

Level III.

Autonomic nervous system monitoring in intensive care as a prognostic tool. Systematic review

Objective

To present a systematic review of the use of autonomic nervous system monitoring as a prognostic tool in intensive care units by assessing heart rate variability.

Methods

Literature review of studies published until July 2016 listed in PubMed/Medline and conducted in intensive care units, on autonomic nervous system monitoring, via analysis of heart rate variability as a prognostic tool (mortality study). The following English terms were entered in the search field: ("autonomic nervous system" OR "heart rate variability") AND ("intensive care" OR "critical care" OR "emergency care" OR "ICU") AND ("prognosis" OR "prognoses" OR "mortality").

Results

There was an increased likelihood of death in patients who had a decrease in heart rate variability as analyzed via heart rate variance, cardiac uncoupling, heart rate volatility, integer heart rate variability, standard deviation of NN intervals, root mean square of successive differences, total power, low frequency, very low frequency, low frequency/high frequency ratio, ratio of short-term to long-term fractal exponents, Shannon entropy, multiscale entropy and approximate entropy.

Conclusion

In patients admitted to intensive care units, regardless of the pathology, heart rate variability varies inversely with clinical severity and prognosis.

Venous oxygen saturation in critical illness

OBJECTIVE

To review clinically relevant features of systemic oxygen delivery and consumption and the technique and use of venous oxygenation monitoring in human and veterinary medicine.

DATA SOURCES

Veterinary and human peer-reviewed medical literature including scientific reviews, clinical and laboratory research articles, and authors' clinical research experience.

SUMMARY

Measurement of venous hemoglobin oxygen saturation (venous oxygenation) provides insight into the balance between oxygen supply and tissue demand. In people, measurement of venous oxygen saturation can reveal decompensation that is missed by physical examination and other routinely monitored parameters. Therefore, measurement of mixed or central venous oxygenation measurement may help guide therapy and predict outcome of critically ill patients. In dogs, low central venous oxygen saturation has been associated with impaired cardiopulmonary function and poor outcome in several small studies of experimental shock or severe clinical illness, suggesting that monitoring this variable may assist the treatment of severe illness in this species as well.

CONCLUSION

Venous oxygenation reflects systemic oxygenation status and can be used to guide treatment and estimate prognosis in critically ill patients. Measurement of venous oxygenation in veterinary patients is feasible and is a potentially valuable tool in the management of patients with severe disease. This review is intended to increase the understanding and awareness of the potential role of venous oxygen measurement in veterinary patients.

Protocolized care for early shock resuscitation

PURPOSE OF REVIEW

Protocolized care for early shock resuscitation (PCESR) has been intensely examined over the last decade. The purpose is to review the pathophysiologic basis, historical origin, clinical applications, components and outcome implications of PCESR.

RECENT FINDINGS

PCESR is a multifaceted systems-based approach that includes early detection of high-risk patients and interventions to rapidly reverse hemodynamic perturbations that result in global or regional tissue hypoxia. It has been applied to perioperative surgery, trauma, cardiology (heart failure and acute myocardial infarction), pulmonary embolus, cardiac arrest, undifferentiated shock, postoperative cardiac surgery and pediatric septic shock. When this approach is used for adult septic shock, in particular, it is associated with a mortality reduction from 46.5 to less than 30% over the last 2 decades. Challenges to these findings are seen when repeated trials contain enrollment, diagnostic and therapeutic methodological differences.

SUMMARY

PCESR is more than a hemodynamic optimization procedure. It also provides an educational framework for the less experienced and objective recognition of clinical improvement or deterioration. It further minimizes practices' variation and provides objective measures that can be audited, evaluated and amendable to continuous quality improvement. As a result, morbidity and mortality are improved.

Fluid overload in children undergoing mechanical ventilation

Patients admitted to an intensive care unit are prone to cumulated fluid overload and receive intravenous volumes through the aggressive resuscitation recommended for septic shock treatment, as well as other fluid sources related to medications and nutritional support. The liberal liquid supply strategy has been associated with higher morbidity and mortality. Although there are few prospective pediatric studies, new strategies are being proposed. This non-systematic review discusses the pathophysiology of fluid overload, its consequences, and the available therapeutic strategies. During systemic inflammatory response syndrome, the endothelial glycocalyx is damaged, favoring fluid extravasation and resulting in interstitial edema. Extravasation to the third space results in longer mechanical ventilation, a greater need for renal replacement therapy, and longer intensive care unit and hospital stays, among other changes. Proper hemodynamic monitoring, as well as cautious infusion of fluids, can minimize these damages. Once cumulative fluid overload is established, treatment with long-term use of loop diuretics may lead to resistance to these medications. Strategies that can reduce intensive care unit morbidity and mortality include the early use of vasopressors (norepinephrine) to improve cardiac output and renal perfusion, the use of a combination of diuretics and aminophylline to induce diuresis, and the use of sedation and early mobilization protocols.

ESTES guidelines: acute mesenteric ischaemia

PURPOSE

Acute mesenteric ischaemia (AMI) accounts for about 1:1000 acute hospital admissions. Untreated, AMI will cause mesenteric infarction, intestinal necrosis, an overwhelming inflammatory response and death. Early intervention can halt and reverse this process leading to a full recovery, but the diagnosis of AMI is difficult and failure to recognize AMI before intestinal necrosis has developed is responsible for the high mortality of the disease. Early diagnosis and prompt treatment are the goals of modern therapy, but there are no randomized controlled trials to guide treatment and the published literature contains a high ratio of reviews to original data. Much of that data comes from case reports and often small, retrospective series with no clearly defined treatment criteria.

METHODS

A study group of the European Society for Trauma and Emergency Surgery (ESTES) was formed in 2013 with the aim of developing guidelines for the management of AMI. A comprehensive literature search was performed using the Medical Subject Heading (MeSH) thesaurus keywords "mesenteric ischaemia", "bowel ischaemia" and "bowel infarction". The bibliographies of relevant articles were screened for additional publications. After an initial systematic review of the literature by the whole group, a steering group formulated questions using a modified Delphi process. The evidence was then reviewed to answer these questions, and recommendations formulated and agreed by the whole group.

RESULTS

The resultant recommendations are presented in this paper.

CONCLUSIONS

The aim of these guidelines is to provide recommendations for practice that will lead to improved outcomes for patients.

Recent Advances of Mucosal Capnometry and the Perspectives of Gastrointestinal Monitoring in the Critically Ill. A Pilot Study

Mucosal capnometry involves the monitoring of partial pressure of carbon dioxide (PCO2) in mucous membranes. Different techniques have been developed and applied for this purpose, including sublingual or buccal sensors, or special gastrointestinal tonometric devices. The primary use of these procedures is to detect compensated shock in critically ill patients or patients undergoing major surgery. Compensatory mechanisms, in the early phases of shock, lead to the redistribution of blood flow towards the vital organs, within ostensibly typical macro-haemodynamic parameters. Unfortunately, this may result in microcirculatory disturbances, which can play a pivotal role in the development of organ failure. In such circumstances mucosal capnometry monitoring, at different gastrointestinal sites, can provide a sensitive method for the early diagnosis of shock. The special PCO2 monitoring methods assess the severity of ischaemia and help to define the necessary therapeutic interventions and testing of these monitors have justified their prognostic value. Gastrointestinal mucosal capnometry monitoring also helps in determining the severity of ischaemia and is a useful adjunctive in the diagnosis of occlusive splanchnic arterial diseases. The supplementary functional information increases the diagnostic accuracy of radiological techniques, assists in creating individualized treatment plans, and helps in follow-up the results of interventions. The results of a pilot study focusing on the interrelation of splanchnic perfusion and gastrointestinal function are given and discussed concerning recent advances in mucosal capnometry.

Hemoglobin optimization and transfusion strategies in patients undergoing cardiac surgery

Although red blood cells (RBCs) transfusion is sometimes associated with adverse reactions, anemia could also lead to increased morbidity and mortality in high-risk patients. For these reasons, the definition of perioperative strategies that aims to detect and treat preoperative anemia, prevent excessive blood loss, and define “optimal” transfusion algorithms is crucial. Although the treatment with preoperative iron and erythropoietin has been recommended in some specific conditions, several controversies exist regarding the benefit-to-risk balance associated with these treatments. Further studies are needed to better define the indications, dosage, and route of administration for preoperative iron with or without erythropoietin supplementation. Although restrictive transfusion strategies in patients undergoing cardiac surgery have been shown to effectively reduce the incidence and the amount of RBCs transfusion without increase in side effects, some high-risk patients (e.g., symptomatic acute coronary syndrome) could benefit from higher hemoglobin concentrations. Despite all efforts made last decade, a significant amount of work remains to be done to improve hemoglobin optimization and transfusion strategies in patients undergoing cardiac surgery.