Physiological effects of hyperchloraemia and acidosis

Optimizing nonintubated laryngeal microsurgery: The effectiveness and safety of superior laryngeal nerve block with high-flow nasal oxygen-A prospective cohort study

BACKGROUND

Laryngeal microsurgery (LMS) typically requires intubated general anesthesia (ITGA). Although nonintubated general anesthesia (NIGA) with high-flow nasal oxygen (HFNO) can be applied with LMS, a muscle relaxant is required, which can cause apnea and hypercapnia. This study evaluated the effectiveness of a superior laryngeal nerve block (SLNB) in improving safety during LMS.

METHODS

This prospective cohort study enrolled a cumulative total of 61 adult patients received LMS under intravenous general anesthesia and allocated to three groups: ITGA group (n = 18), which patients performed intubation; neuromuscular blocking (NMB) group (n = 21), which patients administrated muscle relaxant without intubation and superior laryngeal nerve block (NB) group (n = 22), which patients performed SLNB without intubation or muscle relaxant.

RESULTS

The average (SD) values of PaCO 2 after surgery in ITGA, NMB, and NB group were 50.8 (7.5), 97.5 (24.9), and 54.8 (8.8) mmHg, respectively. The mean postoperative pH values were 7.33 (0.04), 7.14 (0.07), and 7.33 (0.04), respectively. The results were all p < 0.001, and the average pH value of the NMB group was lower than that of the ITGA and NB groups. During the LMS, the mean heart rate (HR) (93.9 [18.1] bpm) and noninvasive blood pressure systolic (NBPs) (143.5 [28.2] mmHg) in the NMB group were higher than those in the ITGA group (HR = 77.4 [13.5] bpm and NBPs = 132.7 [20.8] mmHg) and NB group (HR = 82.3 [17.4] bpm and NBPs = 120.9 [25.0] mmHg). The results of p value by HR and NBPs are p < 0.001. The PaCO 2 and pH values are similar between ITGA group and NB group.

CONCLUSION

Our approach of using HFNO with SLNB was successful for performing nonintubated LMS, enabling the patients to maintain spontaneous breathing and effectively eliminate CO 2 . This approach reduces the risks of hypercapnia and acidosis even when the duration of LMS exceeds 30 minutes.

Prognosis of patients with extreme acidosis on admission to the emergency department: A retrospective cohort study

AIM OF THE STUDY

The development of acidosis in critically ill patients is considered to be a negative prognostic factor, and when extreme, even incompatible with life. We aimed to test the prognosis of patients with a pH lower than 6.9 on emergency department admission.

METHODS

A retrospective cohort study in adult patients admitted to two emergency departments with a pH < 6.9 during the first 12 h of admission. Primary outcome was mortality within 24 h from emergency department admission. We performed a regression analysis of clinical and laboratory data in order to identify factors associated with mortality in this population.

RESULTS

We analyzed data of 206 admissions to the emergency departments between 2008 and 2018 with extreme acidosis. pH Values ranged from 6.898 to 6.35 (mean 6.8 and median 6.83). 60 (29%) of the patients survived the first 24 h. 35 patients (58%) of those also survived to hospital discharge, and of them 80% have returned to their previous functional status. Patient's age, type of acidosis, cardio-pulmonary resuscitation on arrival, and diagnosis on admission were correlated with survival.

CONCLUSIONS

A small but significant portion of patients with extreme acidosis on emergency department admission survive at least to 24 h and until hospital discharge. The clinical decision making should be based on other prognostic factors rather than pH value by itself.

The synergism of cytosolic acidosis and reduced NAD+/NADH ratio is responsible for lactic acidosis-induced vascular smooth muscle cell impairment in sepsis

BACKGROUND

During sepsis, serve vascular dysfunctions lead to life-threatening multiple organ failure, due to vascular smooth muscle cells (VSMC) impairments, resulting in vasoplegia, hypotension and hypoperfusion. In addition, septic patients have an altered cell metabolism that leads to lactic acidosis. Septic patients suffering from lactic acidosis have a high risk of mortality. In addition, septic survivors are at risk of secondary vascular disease. The underlying mechanisms of whether and how lactic acidosis leads to the changes in VSMCs is not well understood. The aim of this study was to comprehensively investigate the effect of lactic acidosis on VSMCs and additionally compare the effects with those induced by pure acidosis and sodium lactate.

METHODS

Primary human aortic smooth muscle cells (HAoSMCs) were treated for 48 h with lactic acidosis (LA_pH 6.8), hydrochloric acid (HCl_pH 6.8), sodium lactate (Na+-lactate_pH 7.4) and the respective controls (ctrl._pH 7.4; hyperosmolarity control: mannitol_pH 7.4) and comparatively analyzed for changes in (i) transcriptome, (ii) energy metabolism, and (iii) phenotype.

RESULTS

Both types of acidosis led to comparable and sustained intracellular acidification without affecting cell viability. RNA sequencing and detailed transcriptome analysis revealed more significant changes for lactic acidosis than for hydrochloric acidosis, with lactate being almost ineffective, suggesting qualitative and quantitative synergism of acidosis and lactate. Bioinformatic predictions in energy metabolism and phenotype were confirmed experimentally. Lactic acidosis resulted in strong inhibition of glycolysis, glutaminolysis, and altered mitochondrial respiration which reduced cellular ATP content, likely due to increased TXNIP expression and altered NAD+/NADH ratio. Hydrochloric acidosis induced significantly smaller effects without changing the NAD+/NADH ratio, with the ATP content remaining constant. These metabolic changes led to osteo-/chondrogenic/senescent transdifferentiation of VSMCs, with the effect being more pronounced in lactic acidosis than in pure acidosis.

CONCLUSIONS

Overall, lactic acidosis exerted a much stronger effect on energy metabolism than pure acidosis, whereas lactate had almost no effect, reflecting the qualitative and quantitative synergism of acidosis and lactate. As a consequence, lactic acidosis may lead to acute functional impairments of VSMC, sustained perturbations of the transcriptome and cellular dedifferentiation. Moreover, these effects may contribute to the acute and prolonged vascular pathomechanisms in septic patients.

A meta-analysis of Lactate Ringer's solution versus Normal Saline in the treatment of acute pancreatitis

Fluid resuscitation is an important way in the treatment of acute pancreatitis (AP). This meta-analysis aimed to compare the safety and efficacy of Lactate Ringer's solution (LR) and Normal Saline (NS) in the treatment of patients with acute pancreatitis. Searched in PubMed, Web of Science Core Collection (Clarivate), Embase, Cochrane Library, CNKI, China Wanfang, and China VIP database. All randomized controlled clinical trials (RCTs) were identified. Six studies with 431 patients were included. Compared with NS, LR can significantly reduce the incidence of SIRS at 24h, reduce the length of hospitalization, moderate-severe AP, ICU admission and local complications, especially pancreatic necrosis. It is safe and effective to choose LR for fluid resuscitation in AP, but due to the small number of included studies, multi-center and large-sample RCTs are still needed for further verification. PROSPERO registration number: CRD42022322788.

Role of Crystalloids in the Perioperative Setting: From Basics to Clinical Applications and Enhanced Recovery Protocols

Perioperative fluid management, a critical aspect of major surgeries, is characterized by pronounced stress responses, altered capillary permeability, and significant fluid shifts. Recognized as a cornerstone of enhanced recovery protocols, effective perioperative fluid management is crucial for optimizing patient recovery and preventing postoperative complications, especially in high-risk patients. The scientific literature has extensively investigated various fluid infusion regimens, but recent publications indicate that not only the volume but also the type of fluid infused significantly influences surgical outcomes. Adequate fluid therapy prescription requires a thorough understanding of the physiological and biochemical principles that govern the body's internal environment and the potential perioperative alterations that may arise. Recently published clinical trials have questioned the safety of synthetic colloids, widely used in the surgical field. A new clinical scenario has arisen in which crystalloids could play a pivotal role in perioperative fluid therapy. This review aims to offer evidence-based clinical principles for prescribing fluid therapy tailored to the patient's physiology during the perioperative period. The approach combines these principles with current recommendations for enhanced recovery programs for surgical patients, grounded in physiological and biochemical principles.

Saline versus Plasma Solution-A in Initial Resuscitation of Patients with Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial

BACKGROUND

Although saline is commonly used during cardiopulmonary resuscitation (CPR) or post-cardiac arrest care, it has detrimental effects. This trial aimed to evaluate the efficacy of a balanced crystalloid solution (Plasma Solution-A [PS]) in out-of-hospital cardiac arrest (OHCA) patients and compare it with the efficacy of saline.

METHODS

A randomized, unblinded clinical trial was conducted using PS and saline for intravenous fluid administration during CPR and post-cardiac arrest care of non-traumatic OHCA patients admitted to the emergency department of a tertiary university hospital. Patients received saline (saline group) or PS (PS group) within 24 h of hospital arrival. The primary outcomes were changes in arterial pH, bicarbonate, base excess (BE), and chloride levels within 24 h. The secondary outcomes were clinical outcomes including mortality.

RESULTS

Of the 364 patients, data from 27 and 26 patients in the saline and PS groups, respectively, were analyzed. Analysis using a linear mixed model revealed a significant difference in BE change over time between the groups (treatment-by-time p = 0.044). Increase in BE and bicarbonate levels from 30 min to 2 h was significantly greater (p = 0.044 and p = 0.024, respectively) and the incidence of hyperchloremia was lower (p < 0.001) in the PS group than in the saline group. However, there was no difference in clinical outcomes.

CONCLUSION

Use of PS for resuscitation resulted in a faster improvement in BE and bicarbonate, especially in the early phase of post-cardiac arrest care, and lower hyperchloremia incidence than the use of saline, without differences in clinical outcomes, in OHCA patients.

The Effect on Serum Electrolytes in Patients Undergoing Elective Craniotomy for Supratentorial Brain Tumors Using PlasmaLyte A and Normal Saline as Intravenous Replacement Fluid

Background and aim The type of fluid which is administered to patients is very crucial and important. In this study normal saline is compared with PlasmaLyte A in patients undergoing craniotomy for supratentorial brain tumors. Generally normal saline is used in neurosurgical patients; it is seen to be associated with hyperchloremic acidosis. A balanced crystalloid, e.g. PlasmaLyte A, maintains a better metabolic status than normal saline. This study was planned to study the metabolic effects of using PlasmaLyte A as compared with normal saline as intravenous fluids in patients undergoing supratentorial brain tumour surgeries. Methods This is a prospective, randomized, double-blinded study in patients undergoing craniotomy for supratentorial brain tumors. Written informed consent was taken from patients and they were divided into two groups, Group A and B of 40 patients each by computer-generated random numbers. Group A received PlasmaLyte A and Group B received normal saline intra-operatively as maintenance fluid. Heart rate, mean arterial pressure, total fluid administered, serum sodium, serum potassium, chloride, lactate, pH, serum urea, serum creatinine, osmolarity, and urine output were assessed at different time intervals in both groups. Blood urea and creatinine were assessed to see acute kidney injury. Results There was no difference in mean values of serum sodium, potassium, lactate, serum urea, creatinine and serum osmolarity in both groups throughout the study period. However there was a rise in serum chloride and a low pH was noted in Group B. The urine output was also similar in both groups. The metabolic status of patients receiving PlasmaLyte was better than those receiving normal saline. Conclusion Normal saline may cause hyperchloremic metabolic acidosis which may be avoided by using balanced crystalloids. The use of balanced crystalloids should be preferred to normal saline in neurosurgical patients to ensure a better metabolic status and good clinical outcome.

Vibrio harveyi co-infected with Cryptocaryon irritans to orange-spotted groupers Epinephelus coioides

The orange-spotted grouper (Epinephelus coioides) is a high economic value aquacultural fish in China, however, it often suffers from the outbreak of parasitic ciliate Cryptocaryon irritans as well as bacterium Vibrio harveyi which bring great loss in grouper farming. In the present study, we established a high dose C. irritans local-infected model which caused the mortality of groupers which showed low vitality and histopathological analysis demonstrated inflammatory response and degeneration in infected skin, gill and liver. In addition, gene expression of inflammatory cytokines was detected to assist the estimate of inflammatory response. Furthermore, we also found that the activity of Na⁺/K⁺ ATPase in gill was decreased in groupers infected C. irritans and the concentration of Na⁺/Cl^- in blood were varied. Base on the morbidity symptom occurring in noninfected organs, we hypothesized that the result of morbidity and mortality were due to secondary bacterial infection post parasitism of C. irritans. Moreover, four strains of bacteria were isolated from the infected site skin and liver of local-infected groupers which were identified as V. harveyi in accordance of phenotypic traits, biochemical characterization and molecular analysis of 16S rDNA genes, housekeeping genes (gyrB and cpn60) and species-specific gene Vhhp2. Regression tests of injecting the isolated strain V. harveyi has showed high pathogenicity to groupers. In conclusion, these findings provide the evidence of coinfections with C. irritans and V. harveyi in orange-spotted grouper.

Effect of Normal Saline versus PlasmaLyte on Coagulation and Metabolic Status in Patients Undergoing Neurosurgical Procedures

Background  The choice of intraoperative fluid in neurosurgical patients is important as we need to maintain adequate cerebral perfusion and oxygenation and also avoid cerebral edema. Normal saline (NS) is commonly used in neurosurgeries, but it leads to hyperchloremic metabolic acidosis, which may result in coagulopathy. Balanced crystalloid with physiochemical composition akin to that of plasma has favorable effects on metabolic profile and may avoid the problems associated with NS. Against this background, the present study aimed to compare the effects of NS versus PlasmaLyte (PL) on coagulation profile in patients undergoing neurosurgical procedures. Methods  This prospective, randomized, double-blinded study was conducted in 100 adult patients scheduled to undergo various neurosurgical procedures. Patients were randomly allocated in two groups of 50 each to receive either NS or PL intraoperatively and postoperatively till 4 hours after the surgery. Hemoglobin, hematocrit, coagulation profile (PT, PTT, and INR), serum chloride, pH, blood urea, and serum creatinine were measured prior to induction (baseline) and 4 hours after completion of surgery. Results  Demographic characteristics were statistically similar between the two groups. Coagulation profile parameters were comparable between the two groups at baseline as well as 4 hours after surgery. pH was significantly lower in the NS group as compared to the PL group at 4 hours after surgery. Postoperatively blood urea, serum creatinine, and serum chloride levels were significantly raised in the NS group as compared to the PL group. Hemoglobin and hematocrit values were similar between the two groups. Conclusion  Coagulation profile parameters were normal and statistically similar with intraoperative infusion of NS versus PL in patients undergoing neurosurgical procedures. However, use of PL was associated with a better acid-base and renal profile in these patients.

Acute Diarrhea and Severe Dehydration in Children: Does Non-anion-gap Component of Severe Metabolic Acidemia Need More Attention?

Background

Despite significant loss of bicarbonate during acute diarrhea, pediatric data are scarce with acute diarrhea/severe dehydration (ADSD) and severe non-anion-gap metabolic acidemia (sNAGMA). We planned to study their clinical profile, critical care needs, and outcome.

Patients

Children (1 month-12 years) with ADSD and sNAGMA (pH <7.2 and/or bicarbonate <15 mEq/L, and normal/mixed anion gap) admitted in Pediatric Emergency Department from January 2016 to December 2018 were enrolled. Children with pure high-anion-gap metabolic acidemia were excluded.

Methods

Medical records were reviewed retrospectively. The primary outcome was time taken to resolve acidemia. Secondary outcomes were acute care area free days in 5 days (ACAFD₅), and adverse outcome as composite of Pediatric Intensive Care Unit (PICU) admission and/or death.

Results

Out of 929 diarrhea patients admitted for intravenous therapy, 121 (13%; median age, 4 months) had ADSD and sNAGMA. Median (IQR) pH was 7.11 (7.01-7.22); 21% patients had pH <7.00. Hyperchloremia (96%) and hypernatremia (45%) were common. About 12% patients each required inotropes and ventilation, while 58% had acute kidney injury (AKI). Median (IQR) time for resolution of acidemia among survivors was 24 (12, 24) hours. Thirty-two patients had adverse outcome. Higher grades of sNAGMA were associated with shock, AKI, coma, hypernatremia, hyperkalemia, adverse outcome, and lesser ACAFD₅. Shock, ventilation, renal replacement therapy (RRT), and higher grades of sNAGMA were predictors of adverse outcome, with former two being independent predictors.

Conclusion

Severe non-anion-gap metabolic acidemia in children with ADSD is associated with organ dysfunctions, dyselectrolytemias, and lesser ACAFD5. Resolution of acidemia took unacceptably longer time. Higher grades of sNAGMA were a predictor of adverse outcomes. Trials are suggested to assess the role of additional bicarbonate therapy.

How to cite this article

Takia L, Baranwal AK, Gupta PK, Angurana SK, Jayashree M. Acute Diarrhea and Severe Dehydration in Children: Does Non-anion-gap Component of Severe Metabolic Acidemia Need More Attention? Indian J Crit Care Med 2022;26(12):1300-1307.

Hyperchloremia and association with acute kidney injury in critically ill children

BACKGROUND

Hyperchloremia has been associated with acute kidney injury (AKI) in critically ill adult patients. Data is limited in pediatric patients. Our study sought to determine if an association exists between hyperchloremia and AKI in pediatric patients admitted to the intensive care unit (PICU).

METHODS

This is a single-center retrospective cohort study of pediatric patients admitted to the PICU for greater than 24 h and who received intravenous fluids. Patients were excluded if they had a diagnosis of kidney disease or required kidney replacement therapy (KRT) within 6 h of admission. Exposures were hyperchloremia (serum chloride ≥ 110 mmol/L) within the first 7 days of PICU admission. The primary outcome was the development of AKI using the Kidney Disease Improving Global Outcomes (KDIGO) criteria. Secondary outcomes included time on mechanical ventilation, new KRT, PICU length of stay, and mortality. Outcomes were analyzed using multivariate logistic regression.

RESULTS

There were 407 patients included in the study, 209 in the hyperchloremic group and 198 in the non-hyperchloremic group. Univariate analysis demonstrated 108 (51.7%) patients in the hyperchloremic group vs. 54 (27.3%) in the non-hyperchloremic group (p =  < .001) with AKI. On multivariate analysis, the odds ratio of AKI with hyperchloremia was 2.24 (95% CI 1.39-3.61) (p = .001). Hyperchloremia was not associated with increased odds of mortality, need for KRT, time on mechanical ventilation, or length of stay.

CONCLUSION

Hyperchloremia was associated with AKI in critically ill pediatric patients. Further pediatric clinical trials are needed to determine the benefit of a chloride restrictive vs. liberal fluid strategy. A higher resolution version of the Graphical abstract is available as Supplementary information.

Association of Arterial pH With Hemodynamic Response to Vasopressin in Patients With Septic Shock: An Observational Cohort Study

OBJECTIVES

Vasopressin is reported to retain vasoconstrictive activity in the setting of acidemia, but preclinical models are inconsistent and studies have not evaluated the clinical effectiveness of vasopressin based on arterial pH. This study sought to determine the association between arterial pH and blood pressure after vasopressin initiation in septic shock.

DESIGN

This retrospective, multicenter, observational cohort study evaluated the association of arterial pH at the time of vasopressin initiation with hemodynamic response to vasopressin and change in catecholamine dose after vasopressin initiation. Hemodynamic response was defined as a catecholamine dose decrease with mean arterial pressure greater than or equal to 65 mm Hg at 6 hours after vasopressin initiation.

SETTING

Patients from eight hospitals in a health system were evaluated.

PATIENTS

Patients with septic shock initiated on vasopressin as a catecholamine adjunct between January 2012 and November 2017 were screened for inclusion.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 1,350 patients were included. At the time of vasopressin initiation patients were severely ill with arterial pH 7.28 ± 0.13, Sequential Organ Failure Assessment 14.1 ± 3.5, lactate 5.6 ± 4.6 mmol/L, and norepinephrine-equivalent catecholamine dose 32.3 ± 25.4 µg/min. After adjusting for lactate and Sequential Organ Failure Assessment with multivariable logistic regression, lower arterial pH was independently associated with lower odds of hemodynamic response to vasopressin (for each 0.1 unit arterial pH was below 7.40, response odds ratio 0.79; 95% CI, 0.72-0.87). For each 0.1 unit the pH was below 7.40 at vasopressin initiation, the norepinephrine-equivalent catecholamine dose increased by 1.5 µg/min (95% CI, 0.5-2.5 µg/min) at 1 hour, and increased by 2.5 µg/min (95% CI, 1.4-3.5 µg/min) at 6 hours after vasopressin initiation.

CONCLUSIONS

Compared with higher arterial pH, patients with septic shock and low arterial pH had lower odds of vasopressin response and higher catecholamine doses after vasopressin initiation. Similar to other vasopressors, the clinical effectiveness of vasopressin appears to be impaired in the setting of acidemia.

Normal Saline Versus Low Chloride Solutions in Treatment of Diabetic Ketoacidosis: A Systematic Review of Clinical Trials

Traditionally, normal saline solution (NSS) has been the fluid of choice in diabetic ketoacidosis (DKA) patients, but the NSS is an acidic fluid and may lead to the delayed resolution of DKA. A systemic review search was conducted on PubMed, Embase, and Central Cochrane Registry to compare the efficacy of low chloride solutions with normal saline solution in DKA resolution. Randomized clinical trials with normal saline as a control arm and low chloride solutions as an intervention arm were included. Four studies were included in the analysis. The investigated outcomes, including time to resolution for DKA and duration of insulin infusion, varied depending on the endpoint were reported in the studies. Overall, balanced solutions were generally associated with faster correction of pH. The time to reach overall DKA endpoints was comparable in both groups. We concluded that crystalloid solutions may be used as an initial resuscitation fluid in the DKA population and may lead to earlier resolution of acidosis. More clinical trial data is required to reach statistical significance for the hypothesis.

Ferret Sedation and Anesthesia

Providing safe anesthetic events in ferrets can be achieved if fundamental principles in anesthesia are followed. Each phase of the anesthetic, event including preanesthetic, maintenance, and postanesthetic phase, have certain considerations. The anesthetic supervisor or veterinarian providing management should have a firm understanding of the species-specific anatomy, physiology, and common indications of general anesthesia along with perspective of their own experience with ferrets. Ensuring these guidelines are followed will facilitate safe administration of general anesthesia in this species.

Effect of Intra- and Post-Operative Fluid and Blood Volume on Postoperative Pulmonary Edema in Patients with Intraoperative Massive Bleeding

In patients with intraoperative massive bleeding, the effects of fluid and blood volume on postoperative pulmonary edema are uncertain. Patients with intraoperative massive bleeding who had undergone a non-cardiac surgery in five hospitals were enrolled in this study. We evaluated the association of postoperative pulmonary edema risk and intra- and post-operatively administered fluid and blood volumes in patients with intraoperative massive bleeding. In total, 2090 patients were included in the postoperative pulmonary edema analysis, and 300 patients developed pulmonary edema within 72 h of the surgery. The postoperative pulmonary edema with hypoxemia analysis included 1660 patients, and the condition occurred in 161 patients. An increase in the amount of red blood cells transfused per hour after surgery increased the risk of pulmonary edema (hazard ratio: 1.03; 95% confidence interval: 1.01–1.05; p = 0.013) and the risk of pulmonary edema with hypoxemia (hazard ratio: 1.04; 95% confidence interval: 1.01–1.07; p = 0.024). An increase in the red blood cells transfused per hour after surgery increased the risk of developing pulmonary edema. This increase can be considered as a risk factor for pulmonary edema.

Monitoring of Lactate in Interstitial Fluid, Saliva and Sweat by Electrochemical Biosensor: The Uncertainties of Biological Interpretation

Lactate electrochemical biosensors were fabricated using Pediococcus sp lactate oxidase (E.C. 1.1.3.2), an external polyurethane membrane laminate diffusion barrier and an internal ionomeric polymer barrier (sulphonated polyether ether sulphone polyether sulphone, SPEES PES). In a needle embodiment, a Pt wire working electrode was retained within stainless steel tubing serving as pseudoreference. The construct gave linearity to at least 25 mM lactate with 0.17 nA/mM lactate sensitivity. A low permeability inner membrane was also unexpectedly able to increase linearity. Responses were oxygen dependent at pO2 < 70 mmHg, irrespective of the inclusion of an external diffusion barrier membrane. Subcutaneous tissue was monitored in Sprague Dawley rats, and saliva and sweat during exercise in human subjects. The tissue sensors registered no response to intravenous Na lactate, indicating a blood-tissue lactate barrier. Salivary lactate allowed tracking of blood lactate during exercise, but lactate levels were substantially lower than those in blood (0–3.5 mM vs. 1.6–12.1 mM), with variable degrees of lactate partitioning from blood, evident both between subjects and at different exercise time points. Sweat lactate during exercise measured up to 23 mM but showed highly inconsistent change as exercise progressed. We conclude that neither tissue interstitial fluid nor sweat are usable as surrogates for blood lactate, and that major reappraisal of lactate sensor use is indicated for any extravascular monitoring strategy for lactate.

The Effect of High-Flow Nasal Oxygen on Carbon Dioxide Accumulation in Apneic or Spontaneously Breathing Adults During Airway Surgery: A Randomized-Controlled Trial

BACKGROUND

High-flow nasal oxygen (HFNO) is an emerging technology that has generated interest in tubeless anesthesia for airway surgery. HFNO has been shown to maintain oxygenation and CO2 clearance in spontaneously breathing patients and is an effective approach to apneic oxygenation. Although it has been suggested that HFNO can enhance CO2 clearance during apnea, this has not been established. The true extent of CO2 accumulation and resulting acidosis using HFNO during prolonged tubeless anesthesia remains undefined.

METHODS

In a single-center trial, we randomly assigned 20 adults undergoing microlaryngoscopy to apnea or spontaneous ventilation (SV) using HFNO during 30 minutes of tubeless anesthesia. Serial arterial blood gas analysis was performed during preoxygenation and general anesthesia. The primary outcome was the partial pressure of CO2 (Paco2) after 30 minutes of general anesthesia, with each group compared using a Student t test.

RESULTS

Nineteen patients completed the study protocol (9 in the SV group and 10 in the apnea group). The mean (standard deviation [SD]) Paco2 was 89.0 mm Hg (16.5 mm Hg) in the apnea group and 55.2 mm Hg (7.2 mm Hg) in the SV group (difference in means, 33.8; 95% confidence interval [CI], 20.6-47.0) after 30 minutes of general anesthesia (P < .001). The average rate of Paco2 rise during 30 minutes of general anesthesia was 1.8 mm Hg/min (SD = 0.5 mm Hg/min) in the apnea group and 0.8 mm Hg/min (SD = 0.3 mm Hg/min) in the SV group. The mean (SD) pH was 7.11 (0.04) in the apnea group and 7.29 (0.06) in the SV group (P < .001) at 30 minutes. Five (55%) of the apneic patients had a pH <7.10, of which the lowest measurement was 7.057. No significant difference in partial pressure of arterial O2 (Pao2) was observed after 30 minutes of general anesthesia.

CONCLUSIONS

CO2 accumulation during apnea was more than double that of SV after 30 minutes of tubeless anesthesia using HFNO. The use of robust measurement confirms that apnea with HFNO is limited by CO2 accumulation and the concomitant severe respiratory acidosis, in contrast to SV. This extends previous knowledge and has implications for the safe application of HFNO during prolonged procedures.

Intraoperative management and hemodynamic monitoring for ma- jor abdominal surgery : a narrative review

Background : Several trials suggest that postoperative outcomes may be improved by the use of hemodynamic monitoring, but a survey by the American Society of Anesthesiologists (ASA) and the European Society of Anaesthesiology (ESA) showed that cardiac output is monitored by only 34% of ASA and ESA respondents and central venous pressure is monitored by 73% of ASA respondents and 84% of ESA respondents. Moreover, 86.5% of ASA respondents and 98.1% of ESA respondents believe that their current hemodynamic management could be improved (1). The interaction of general anesthesia and surgical stress is the main problem and the leading cause for postoperative morbidity and mortality. The choice of a suitable hemodynamic monitoring system for patients at high anesthesiological risk is of crucial importance to reduce the incidence of major postoperative complications. The aim of the present review is to summarize the benefits of a defined path beginning before surgery, and discuss the available evidence supporting the efficacy and safety of an individualized hemodynamic approach for major abdominal surgery. Objective : To evaluate the clinical effectiveness of a perioperative hemodynamic therapy algorithm in high risk patients

High Chloride Burden and Clinical Outcomes in Critically Ill Patients With Large Hemispheric Infarction

Background: In general, disease severity has been found to be associated with abnormal chloride levels in critically ill patients, but hyperchloremia is associated with mixed results regarding patient-centered clinical outcomes. We aimed to investigate the impact of maximum serum chloride concentration on the clinical outcomes of critically ill patients with large hemispheric infarction (LHI).

Methods: We conducted a retrospective observational cohort study using prospective institutional neurocritical care registry data from 2013 to 2018. Patients with LHIs involving over two-thirds of middle cerebral artery territory, with or without infarction of other vascular territories, and a baseline National Institutes of Health Stroke Scale score of ≥13 were assessed. Those with a baseline creatinine clearance of <15 mL/min and required neurocritical care for <72 h were excluded. Primary outcome was in-hospital mortality. Secondary outcomes included 3-month mortality and acute kidney injury (AKI) occurrence. Outcomes were compared to different maximum serum chloride levels (5 mmol/L increases) during the entire hospitalization period using multivariable logistic regression analyses.

Results: Of 90 patients, 20 (22.2%) died in-hospital. Patients who died in-hospital had significantly higher maximum serum chloride levels than did those who survived up to hospital discharge (139.7 ± 8.1 vs. 119.1 ± 10.4 mmol/L; p < 0.001). After adjusting for age, sex, and Glasgow coma scale score, each 5-mmol/L increase in maximum serum chloride concentration was independently associated with an increased risk of in-hospital mortality (adjusted odds ratio (aOR), 4.34; 95% confidence interval [CI], 1.98–9.50; p < 0.001). Maximum serum chloride level was also an independent risk factor for 3-month mortality (aOR, 1.99 [per 5 mmol/L increase]; 95% CI, 1.42–2.79; p < 0.001) and AKI occurrence (aOR, 1.57 [per 5 mmol/L increase]; 95% CI, 1.18–2.08; p = 0.002).

Conclusions: High maximum serum chloride concentrations were associated with poor clinical outcomes in critically ill patients with LHI. This study highlights the importance of monitoring serum chloride levels and avoiding hyperchloremia in this patient population.

Fluid Therapy During Cardiopulmonary Resuscitation

Cardiopulmonary arrest (CPA), the acute cessation of blood flow and ventilation, is fatal if left untreated. Cardiopulmonary resuscitation (CPR) is targeted at restoring oxygen delivery to tissues to mitigate ischemic injury and to provide energy substrate to the tissues in order to achieve return of spontaneous circulation (ROSC). In addition to basic life support (BLS), targeted at replacing the mechanical aspects of circulation and ventilation, adjunctive advanced life support (ALS) interventions, such as intravenous fluid therapy, can improve the likelihood of ROSC depending on the specific characteristics of the patient. In hypovolemic patients with CPA, intravenous fluid boluses to improve preload and cardiac output are likely beneficial, and the use of hypertonic saline may confer additional neuroprotective effects. However, in euvolemic patients, isotonic or hypertonic crystalloid boluses may be detrimental due to decreased tissue blood flow caused by compromised tissue perfusion pressures. Synthetic colloids have not been shown to be beneficial in patients in CPA, and given their documented potential for harm, they are not recommended. Patients with documented electrolyte abnormalities such as hypokalemia or hyperkalemia benefit from therapy targeted at those disturbances, and patients with CPA induced by lipid soluble toxins may benefit from intravenous lipid emulsion therapy. Patients with prolonged CPA that have developed significant acidemia may benefit from intravenous buffer therapy, but patients with acute CPA may be harmed by buffers. In general, ALS fluid therapies should be used only if specific indications are present in the individual patient.

[Therapeutics for acute tubular necrosis in 2020]

Acute kidney injury is a major cause of in-hospital morbidity and mortality because of the serious nature of the underlying illnesses and the high incidence of complications. The two major causes of acute kidney injury that occur in the hospital are prerenal disease and acute tubular necrosis. Acute tubular necrosis has a histological definition, even if a kidney biopsy is rarely performed. Kidney injuries occurring during acute tubular necrosis are underlined by different pathophysiological mechanisms that emphasize the role of hypoxia on the tubular cells such as apoptosis, cytoskeleton disruption, mitochondrial function and the inflammation mediated by innate immune cells. The microcirculation and the endothelial cells are also the targets of hypoxia-mediated impairment. Repair mechanisms are sometimes inadequate because of pro-fibrotic factors that will lead to chronic kidney disease. Despite all the potential therapeutic targets highlighted by the pathophysiological knowledge, further works remain necessary to find a way to prevent these injuries.

Low- versus High-Chloride Content Intravenous Solutions for Perioperative Patients: A Systematic Review and Meta-Analysis

Background

Studies have shown complications of normal saline infusion because of its high-chloride content. Therefore, in the present study, we aimed to explore whether the use of low- versus high-chloride solutions benefited the unselected and specifically perioperative patients and was associated with different outcomes.

Methods

Studies on the use of low- versus high-chloride content intravenous solutions for perioperative patients, published up to July 15, 2019, were systematically reviewed, and primary and secondary outcomes were quantitatively summarized.

Results

A total of 14 eligible randomized controlled trials with 943 perioperative patients were included. Five studies reported all-cause mortality, and eight studies provided detailed data on renal replacement therapy (RRT). The pooled result suggested no statistically significant difference in the effect of low- versus high-chloride solutions on all-cause mortality (risk ratio (RR) = 1.39; 95%confidence interval (CI) = 0.23–8.26) and RRT (RR = 1.05; 95%CI = 0.63–1.76). The pooled results on acute kidney injury (AKI) and the use of allogenic blood transfusion (P > 0.05) were similar.

Conclusion

Among specific perioperative patients, the use of low- versus high-chloride content intravenous solutions did not reduce the all-cause mortality, risk of severe AKI, or rate of RRT use. Further large randomized clinical trials are needed to confirm or refute this finding.

Clinical physiology aspects of chloremia in fluid therapy: a systematic review

Background

This systematic review discusses a clinical physiology aspect of chloride in fluid therapy. Crystalloid solutions are one of the most widely used remedies. While generally used in medicine for almost 190 years, studies focused largely on their safety have only been published since the new millennium. The most widely used solution, normal saline, is most often referred to in this context. Its excessive administration results in hyperchloremic metabolic acidosis with other consequences, including higher mortality rates.

Methods

Original papers and review articles eligible for developing the present paper were identified by searching online in the electronic MEDLINE database. The keywords searched for included hyperchloremia, hypochloremia, and compound words containing the word “chloride,” infusion therapy, metabolic acidosis, renal failure, and review.

Results

A total of 21,758 papers published before 31 May 2020 were identified; of this number, 630 duplicates were removed from the list. Upon excluding articles based on their title or abstract, 1850 papers were screened, of which 63 full-text articles were assessed.

Conclusions

According to the latest medical concepts, dyschloremia (both hyperchloremia and hypochloremia) represents a factor indisputably having a negative effect on selected variables of clinical outcome. As infusion therapy can significantly impact chloride homeostasis of the body, the choice of infusion solutions should always take into account the potentially adverse impact of chloride content on chloremia and organ function.

The Heart in Diabetic Ketoacidosis: A Narrative Review Focusing on the Acute Cardiac Effects and Electrocardiographic Abnormalities

Diabetic ketoacidosis (DKA) is a serious complication of diabetes mellitus. Hyperglycemia, acidosis, and electrolyte imbalances can directly affect the heart by inducing toxicity, impairing myocardial blood flow, autonomic dysfunction, and altering activation and conduction of electrical impulses throughout the heart, increasing the risk of arrhythmias and ischemia. The electrocardiogram is useful in monitoring patients during and after an episode of DKA, as it allows the detection of arrhythmias and guides metabolic correction. Unfortunately, reports on electrocardiographic abnormalities in patients with DKA are lacking. We found two electrocardiographic patterns that are frequently reported in the literature: a pseudo-myocardial infarction and a Brugada Phenocopy. Both are associated with DKA metabolic anomalies and they resolve after treatment. Because of their clinical relevance and the challenge they represent for clinicians, we analyzed the clinical characteristics of these patients and the mechanisms involved in these electrocardiographic findings.

Fluid therapy in mechanically ventilated critically ill children: the sodium, chloride and water burden of fluid creep

Background

Fluid therapy is a cornerstone of pediatric intensive care medicine. We aimed at quantifying the load of water, sodium and chloride due to different fluid indications in our pediatric intensive care unit (PICU). We were particularly interested in the role of fluid creep, i.e. fluid administered mainly as the vehicle for drugs, and the association between sodium load and water balance.

Methods

Critically ill children aged ≤3 years and invasively ventilated for ≥48 h between 2016 and 2019 in a single tertiary center PICU were retrospectively enrolled. Need for renal replacement therapy, plasmapheresis or parenteral nutrition constituted exclusion criteria. Quantity, quality and indication of fluids administered intravenously or enterally, urinary output and fluid balance were recorded for the first 48 h following intubation. Concentrations of sodium and chloride provided by the manufacturers were used to compute the electrolyte load.

Results

Forty-three patients (median 7 months (IQR 3–15)) were enrolled. Patients received 1004 ± 284 ml of water daily (153 ± 36 ml/kg/day), mainly due to enteral (39%), creep (34%) and maintenance (24%) fluids. Patients received 14.4 ± 4.8 mEq/kg/day of sodium and 13.6 ± 4.7 mEq/kg/day of chloride, respectively. The majority of sodium and chloride derived from fluid creep (56 and 58%). Daily fluid balance was 417 ± 221 ml (64 ± 30 ml/kg/day) and was associated with total sodium intake (r² = 0.49, p < 0.001).

Conclusions

Critically ill children are exposed, especially in the acute phase, to extremely high loads of water, sodium and chloride, possibly contributing to edema development. Fluid creep is quantitatively the most relevant fluid in the PICU and future research efforts should address this topic in order to reduce the inadvertent water and electrolyte burden and improve the quality of care of critically ill children.

Cardiorespiratory physiological perturbations after acute smoke-induced lung injury and during extracorporeal membrane oxygenation support in sheep

Background: Numerous successful therapies developed for human medicine involve animal experimentation. Animal studies that are focused solely on translational potential, may not sufficiently document unexpected outcomes. Considerable amounts of data from such studies could be used to advance veterinary science. For example, sheep are increasingly being used as models of intensive care and therefore, data arising from such models must be published. In this study, the hypothesis is that there is little information describing cardiorespiratory physiological data from sheep models of intensive care and the author aimed to analyse such data to provide biological information that is currently not available for sheep that received extracorporeal life support (ECLS) following acute smoke-induced lung injury. Methods: Nineteen mechanically ventilated adult ewes undergoing intensive care during evaluation of a form of ECLS (treatment) for acute lung injury were used to collate clinical observations. Eight sheep were injured by acute smoke inhalation prior to treatment (injured/treated), while another eight were not injured but treated (uninjured/treated). Two sheep were injured but not treated (injured/untreated), while one received room air instead of smoke as the injury and was not treated (placebo/untreated). The data were then analysed for 11 physiological categories and compared between the two treated groups. Results: Compared with the baseline, treatment contributed to and exacerbated the deterioration of pulmonary pathology by reducing lung compliance and the arterial oxygen partial pressure to fractional inspired oxygen (PaO 2/FiO 2) ratio. The oxygen extraction index changes mirrored those of the PaO 2/FiO 2 ratio. Decreasing coronary perfusion pressure predicted the severity of cardiopulmonary injury. Conclusions: These novel observations could help in understanding similar pathology such as that which occurs in animal victims of smoke inhalation from house or bush fires, aspiration pneumonia secondary to tick paralysis and in the management of the severe coronavirus disease 2019 (COVID-19) in humans.

Comparison Between Sodium Acetate and Sodium Chloride in Parenteral Nutrition for Very Preterm Infants on the Acid-Base Status and Neonatal Outcomes

PURPOSE

To compare between sodium acetate (SA) and sodium chloride (SC) in parenteral nutrition (PN) with associated metabolic acidosis and neonatal morbidities in preterm infants.

METHODS

Preterm infants below 33 weeks gestational age, and with a birth weight under 1,301 g were enrolled and further stratified into two groups: i) <1,000 g, or ii) ≥1,000 g in birth weight. The subjects were randomized to receive PN containing SA or SC within the first day of life. The results of routine blood investigations for the first 6 days of PN were collated, and the neonatal outcomes were recorded upon discharge or demise.

RESULTS

Fifty-two infants entered the study, with 26 in each group: 29 infants had extremely low birth weight (ELBW). There were no significant differences in birth weight, gestation, sex, exposure to chorioamnionitis and antenatal steroids, surfactant doses and duration of mechanical ventilation between groups. The SA group had significantly higher mean pH and base excess (BE) from days 4 to 6 than the SC (mean pH, 7.36 vs. 7.34; mean BE -1.6 vs. -3.5 [p<0.01]), with a two-fold increase in the mean BE among ELBW infants. Significantly fewer on SA required additional bicarbonate (n=4 vs. 13, p=0.01). The rate of bronchopulmonary dysplasia (BPD) was approximately four-fold lower in SA than SC (n=3 vs. 11, p<0.01). No significant differences were observed in necrotizing enterocolitis, patent ductus arteriosus, retinopathy of prematurity, cholestatic jaundice, and mortality between groups.

CONCLUSION

The use of SA in PN was associated with reduced metabolic acidosis and fewer BPD.

Saline versus Lactated Ringer’s Solution

Background

Both saline and lactated Ringer’s solutions are commonly given to surgical patients. However, hyperchloremic acidosis consequent to saline administration may provoke complications. The authors therefore tested the primary hypothesis that a composite of in-hospital mortality and major postoperative complications is less common in patients given lactated Ringer’s solution than normal saline.

Methods

The authors conducted an alternating cohort controlled trial in which adults having colorectal and orthopedic surgery were given either lactated Ringer’s solution or normal saline in 2-week blocks between September 2015 and August 2018. The primary outcome was a composite of in-hospital mortality and major postoperative renal, respiratory, infectious, and hemorrhagic complications. The secondary outcome was postoperative acute kidney injury.

Results

Among 8,616 qualifying patients, 4,187 (49%) were assigned to lactated Ringer’s solution, and 4,429 (51%) were assigned to saline. Each group received a median 1.9 l of fluid. The primary composite of major complications was observed in 5.8% of lactated Ringer’s versus 6.1% of normal saline patients, with estimated average relative risk across the components of the composite of 1.16 (95% CI, 0.89 to 1.52; P = 0.261). The secondary outcome, postoperative acute kidney injury, Acute Kidney Injury Network stage I–III versus 0, occurred in 6.6% of lactated Ringer’s patients versus 6.2% of normal saline patients, with an estimated relative risk of 1.18 (99.3% CI, 0.99 to 1.41; P = 0.009, significance criterion of 0.007). Absolute differences between the treatment groups for each outcome were less than 0.5%, an amount that is not clinically meaningful.

Conclusions

In elective orthopedic and colorectal surgery patients, there was no clinically meaningful difference in postoperative complications with lactated Ringer’s or saline volume replacement. Clinicians can reasonably use either solution intraoperatively.

Editor’s Perspective

What We Already Know about This Topic

What This Article Tells Us That Is New

The Impact of Changes to an Electronic Admission Order Set on Prescribing and Clinical Outcomes in the Intensive Care Unit

BACKGROUND

Implementation of disease-specific order sets has improved compliance with standards of care for a variety of diseases. Evidence of the impact admission order sets can have on care is limited.

OBJECTIVE

The main purpose of this article is to evaluate the impact of changes made to an electronic critical care admission order set on provider prescribing patterns and clinical outcomes.

METHODS

A retrospective, observational before-and-after exploratory study was performed on adult patients admitted to the medical intensive care unit using the Inpatient Critical Care Admission Order Set. The primary outcome measure was the percentage change in the number of orders for scheduled acetaminophen, a histamine-2 receptor antagonist (H2RA), and lactated ringers at admission before implementation of the revised order set compared with after implementation. Secondary outcomes assessed clinical impact of changes made to the order set.

RESULTS

The addition of a different dosing strategy for a medication already available on the order set (scheduled acetaminophen vs. as needed acetaminophen) had no impact on physician prescribing (0 vs. 0%, p = 1.000). The addition of a new medication class (an H2RA) to the order set significantly increased the number of patients prescribed an H2RA for stress ulcer prophylaxis (0 vs. 20%, p < 0.001). Rearranging the list of maintenance intravenous fluids to make lactated ringers the first fluid option in place of normal saline significantly decreased the number of orders for lactated ringers (17 vs. 4%, p = 0.005). The order set changes had no significant impact on clinical outcomes such as incidence of transaminitis, gastrointestinal bleed, and acute kidney injury.

CONCLUSION

Making changes to an admission order set can impact provider prescribing patterns. The type of change made to the order set, in addition to the specific medication changed, may have an effect on how influential the changes are on prescribing patterns.

The Influence of Chloride for the Interpretation of Plasma Bicarbonate During the Treatment of Diabetic Ketoacidosis

INTRODUCTION

Hyperchloremic metabolic acidosis can occur in diabetic ketoacidosis (DKA) and may affect the acid-base interpretation during treatment.

OBJECTIVES

This study aims to describe the prevalence of hyperchloremia during the treatment of DKA and its effect on the interpretation of bicarbonate value.

METHODS

A cross-sectional study, including all cases of DKA in patients aged 1 to 18 years old admitted from 2010 to 2015, was performed. Laboratory tests were performed on admission (baseline), 2 and 6 hours after admission, and when resolution of DKA was achieved. Adjusted bicarbonate value was calculated using regression equations.

RESULTS

Seventy-nine DKA episodes were included. The average age was 13.3 ± 3.8 years. Baseline levels were as follows: plasma glucose, 479 ± 133 mg/dL; pH 7.1 ± 0.083; bicarbonate, 9.65 ± 2.9; and anion gap, 23.9 ± 7.5. The time to achieve resolution of DKA was 12.2 ± 4.4 hours, and the decrease in capillary glucose was 25.5 (19.7-38.2) mg/dL per hour. After 6 hours of treatment, the proportion of patients presenting hyperchloremia increased from 23% to 77%. By using adjusted bicarbonate, the percentage of patients achieving resolution of DKA after 6 hours of treatment would have been 35.4% (confidence interval 95%, 28-49), in comparison with 24.1% (confidence interval 95%, 18-37) using observed bicarbonate (P = 0.004).

CONCLUSIONS

The hyperchloremia developed during the treatment of DKA could modify the value of measured plasma bicarbonate concentration and unnecessarily prolong the initial phase of treatment.

Fluid therapy in non-septic, refractory acute decompensated heart failure patients - The cautious role of central venous pressure

PURPOSE

Fluid therapy in congestive acute decompensated heart failure (ADHF) patients might be inappropriate and worsening the prognosis. The aim of our study was to analyze the effect of fluid administration on mortality in non-septic, ADHF patients with reduced ejection fraction.

MATERIAL AND METHODS

We analyzed 41 ADHF consecutive 'cold-wet' patients (mean age 69.3 ± 14.9 years, 27 men, LVEF 22.8 ± 11.1%, lactates 2.2 ± 1.6 mmol/L) without sepsis. At admission central venous pressure (CVP) was measured (17.6 ± 7.2 cm H₂O), and ultrasound examination of inferior vena cava (IVC) was performed (IVC min. 18.6 ± 7.3 mm and IVC max. 24.6 ± 4.3 mm). Moreover, the groups were compared (survivors vs. non-survivors as well as 1st and 4th quartile of CVP).

RESULTS

Altogether 17 (41%) patients died: 16 (39%) during a mean of 11.2 ± 7.8 days of hospitalization and 1 during a 30-day follow up. Patients in the lowest CVP quartile (<13 cm H₂O) had significantly worse in-hospital survival as compared to patients in the highest quartile (>24 cm H₂O), P = 0.012. Higher intravenous fluid volumes within the first 24 h were infused in patients in the lowest CVP quartile as compared to the highest CVP quartile (1791.7 ± 1357.8 mL vs. 754.5 ± 631.4 mL, P = 0.046). Moreover, more fluids were infused in a group of patients who died during a hospital stay and at 30-day follow up (1362.8 ± 752.7 mL vs. 722.7 ± 1046.5 mL, P = 0.004; 1348.8 ± 731.0 mL vs. 703.6 ± 1068.4 mL, P = 0.002, respectively).

CONCLUSIONS

CVP-guided intravenous fluid therapy is a common practice which in high risk ADHF 'cold-wet' patients might be harmful and should rather be avoided. Lower CVP seems to be related with worse prognosis.

Hypotonic versus isotonic maintenance fluid administration in the pediatric surgical patient. Semin Pediatr Surg 2019;28:43-46. [PMID: 30824133 DOI: 10.1053/j.sempedsurg.2019.01.007]

Intravenous fluid administration has been occurring for well over one hundred years for a variety of pediatric disease processes. Surprisingly, clinicians have yet to agree upon a standardized intravenous solution. There is ongoing debate regarding the administration of isotonic versus hypotonic fluids as maintenance solutions. In this article, we will review what is known about different maintenance solutions, discuss the potential complications with their use, and summarize the available evidence to help guide clinicians in their choice of maintenance fluids for their patients.

Are we close to the ideal intravenous fluid?

The approach to i.v. fluid therapy for hypovolaemia may significantly influence outcomes for patients who experience a systemic inflammatory response after sepsis, trauma, or major surgery. Currently, there is no single i.v. fluid agent that meets all the criteria for the ideal treatment for hypovolaemia. The physician must choose the best available agent(s) for each patient, and then decide when and how much to administer. Findings from large randomized trials suggest that some colloid-based fluids, particularly starch-based colloids, may be harmful in some situations, but it is unclear whether they should be withdrawn from use completely. Meanwhile, crystalloid fluids, such as saline 0.9% and Ringer's lactate, are more frequently used, but debate continues over which preparation is preferable. Perhaps most importantly, it remains unclear how to select the optimal dose of fluid in different patients and different clinical scenarios. There is good reason to believe that both inadequate and excessive i.v. fluid administration may lead to poor outcomes, including increased risk of infection and organ dysfunction, for hypovolaemic patients. In this review, we summarize the current knowledge on this topic and identify some key pitfalls and some areas of agreed best practice.

When kidneys and lungs suffer together

A significant interaction between kidneys and lungs has been shown in physiological and pathological conditions. The two organs can both be targets of the same systemic disease (eg., some vasculitides). Moreover, loss of normal function of either of them can induce direct and indirect dysregulation of the other one. Subjects suffering from COPD may have systemic inflammation, hypoxemia, endothelial dysfunction, increased sympathetic activation and increased aortic stiffness. As well as the exposure to nicotine, all the foresaid factors can induce a microvascular damage, albuminuria, and a worsening of renal function. Renal failure in COPD can be unrecognized since elderly and frail patients may have normal serum creatinine concentration. Lungs and kidneys participate in maintaining the acid-base balance. Compensatory role of the lungs rapidly expresses through an increase or reduction of ventilation. Renal compensation usually requires a few days as it is achieved through changes in bicarbonate reabsorption. Chronic kidney disease and end-stage renal diseases increase the risk of pneumonia. Vaccination against Streptococcus pneumonia and seasonal influenza is recommended for these patients. Vaccines against the last very virulent H1N1 influenza A strain are also available and effective. Acute lung injury and acute kidney injury are frequent complications in critical illnesses, associated with high morbidity and mortality. The concomitant failure of kidneys and lungs implies a multidisciplinary approach, both in terms of diagnostic processes and therapeutic management.

Fluid Management in Acute Brain Injury

PURPOSE OF THE REVIEW

The aims of fluid management in acute brain injury are to preserve or restore physiology and guarantee appropriate tissue perfusion, avoiding potential iatrogenic effects. We reviewed the literature, focusing on the clinical implications of the selected papers. Our purposes were to summarize the principles regulating the distribution of water between the intracellular, interstitial, and plasma compartments in the normal and the injured brain, and to clarify how these principles could guide fluid administration, with special reference to intracranial pressure control.

RECENT FINDINGS

Although a considerable amount of research has been published on this topic and in general on fluid management in acute illness, the quality of the evidence tends to vary. Intravascular volume management should aim for euvolemia. There is evidence of harm with aggressive administration of fluid aimed at achieving hypervolemia in cases of subarachnoid hemorrhage. Isotonic crystalloids should be the preferred agents for volume replacement, while colloids, glucose-containing hypotonic solutions, and other hypotonic solutions or albumin should be avoided. Osmotherapy seems to be effective in intracranial hypertension management; however, there is no clear evidence regarding the superiority of hypertonic saline over mannitol. Fluid therapy plays an important role in the management of acute brain injury patients. However, fluids are a double-edged weapon because of the potential risk of hyper-hydration, hypo- or hyper-osmolar conditions, which may unfavorably affect the clinical course and the outcome.

Thromboelastometry-guided hemostatic therapy for hemorrhagic shock in the postoperative period of vascular surgery: a case report

Background

Hemorrhagic shock is a medical emergency that often complicates vascular surgery and can lead to death. Hemorrhagic shock is characterized by hypoperfusion and hemodynamic abnormalities leading to the collapse of homeostasis due to massive blood loss. Early diagnosis is critical for a favorable outcome. Thromboelastometry has been considered an effective tool for bleeding management in critically ill patients. Thromboelastometry can guide transfusion therapy quickly, reducing the need for blood products. Therefore, it could be an alternative test to guide hemostatic therapy in complex cases of hemorrhagic shock as a result of vascular surgeries. We report our successful experience with a case of hemorrhagic shock in postoperative care in vascular surgery, in which bleeding management was guided by thromboelastometry and bleeding control was achieved with hemostatic drugs and coagulation factor concentrates.

Case presentation

We report a case of an 82-year-old Afro-Brazilian man who presented to the intensive care unit with hemorrhagic shock in the postoperative period of vascular surgery. He underwent surgery for correction of iliac artery aneurysm with endoleak. His laboratory tests revealed severe anemia (hemoglobin 7.4 mg/dL), metabolic acidosis (bicarbonate 10 mEq/L, pH 7.11), acute kidney injury (creatinine 3.1 mg/dL), thrombocytopenia (platelets count 83 × 10³/mm³), hypofibrinogenemia (70 mg/dL), international nationalized ratio 1.95, activated partial thromboplastin time 64.5 seconds, and lactate 87 mmol/L. There was active bleeding in surgical site. Bleeding management was guided by thromboelastometry. The first test showed fulminant hyperfibrinolysis, which was corrected with the administration of tranexamic acid. The second thromboelastometry test showed improvement of hyperfibrinolysis but severe hypocoagulability. Fibrinogen concentrate, platelet apheresis, cryoprecipitate, and prothrombin complex concentrate were sequentially administrated. Thromboelastometry was completely corrected after 2 hours. Arteriography to evaluate mechanical cause of bleeding was normal. No more bleeding was identified, and neither was any further transfusion needed. He was discharged from the intensive care unit from the ward 3 days after admission.

Conclusions

Thromboelastometry may be considered a useful, feasible and safe tool to monitor and manage coagulopathy in patients with hemorrhagic shock. Moreover, it has the potential benefit of allowing rapid diagnosis,  goal-directed therapy with hemostatic drugs and coagulation factor concentrates and thus, avoiding unnecessary blood component transfusion.

Perioperative metabolic acidosis: The Bradford Anaesthetic Department Acidosis Study

Metabolic acidosis is considered deleterious but is common in post-surgical patients admitted to intensive care unit. We evaluated the prevalence and time course of metabolic acidosis in elective major surgery, and generated hypotheses about causes, by hourly arterial blood sampling in 92 patients. Metabolic acidosis began before incision and most had occurred by the next hour. Seventy-eight per cent of patients had a significant metabolic acidosis post-operatively. Two overlapping phases were observed. The early phase started before incision, characterised by a rising chloride and falling anion gap, unrelated to saline use. The late phase was partly associated with lactate, related to surgery type, and early fluids appeared protective. There was a trend towards longer intensive care unit (+1.3 days) and hospital (+3.2 days) stay with metabolic acidosis. This is the first large study of the evolution of this common finding, demonstrating a pre-incision component. The early phase appears unavoidable or unpredictable, but the late phase might be modified by early fluid administration. It remains unclear whether acidosis of this type should be avoided.

Effects of the Kv7 voltage-activated potassium channel inhibitor linopirdine in rat models of haemorrhagic shock

Recently, we demonstrated that Kv7 voltage-activated potassium channel inhibitors reduce fluid resuscitation requirements in short-term rat models of haemorrhagic shock. The aim of the present study was to further delineate the therapeutic potential and side effect profile of the Kv7 channel blocker linopirdine in various rat models of severe haemorrhagic shock over clinically relevant time periods. Intravenous administration of linopirdine, either before (1 or 3 mg/kg) or after (3 mg/kg) a 40% blood volume haemorrhage, did not affect blood pressure and survival in lethal haemorrhage models without fluid resuscitation. A single bolus of linopirdine (3 mg/kg) at the beginning of fluid resuscitation after haemorrhagic shock transiently reduced early fluid requirements in spontaneously breathing animals that were resuscitated for 3.5 hours. When mechanically ventilated rats were resuscitated after haemorrhagic shock with normal saline (NS) or with linopirdine-supplemented (10, 25 or 50 μg/mL) NS for 4.5 hours, linopirdine significantly and dose-dependently reduced fluid requirements by 14%, 45% and 55%, respectively. Lung and colon wet/dry weight ratios were reduced with linopirdine (25/50 μg/mL). There was no evidence for toxicity or adverse effects based on measurements of routine laboratory parameters and inflammation markers in plasma and tissue homogenates. Our findings support the concept that linopirdine-supplementation of resuscitation fluids is a safe and effective approach to reduce fluid requirements and tissue oedema formation during resuscitation from haemorrhagic shock.

What is the Preferred Resuscitation Fluid for Patients with Severe Sepsis and Septic Shock?

BACKGROUND

Current guidelines for the management of patients with severe sepsis and septic shock recommend crystalloids as the initial fluid solution of choice in the resuscitation of these patients. In recent years, there have been numerous studies published on the type of fluid used in the resuscitation of patients with sepsis. The primary goal of this article is to determine the preferred intravenous fluid for the resuscitation of patients with severe sepsis and septic shock.

METHODS

A MEDLINE literature review was completed to identify studies that investigated the type of resuscitation fluid in the management of patients with severe sepsis and septic shock. Articles included were those published in English between 2011 and 2016, enrolled human subjects, and limited to the following types: randomized controlled trial, prospective observational trial, retrospective cohort trial, and meta-analyses. All selected articles then underwent a structured review by the authors.

RESULTS

Nine thousand sixty-two articles were identified in the search. After use of predetermined criteria, 17 articles were selected for review. Eleven of these were original investigations and six were meta-analyses and systemic reviews.

CONCLUSION

Crystalloids are the preferred solution for the resuscitation of emergency department patients with severe sepsis and septic shock. Balanced crystalloids may improve patient-centered outcomes and should be considered as an alternative to normal saline, if available. There is strong evidence that suggests semi-synthetic colloids decrease survival and should be avoided. The role of albumin in the resuscitation of patients with severe sepsis and sepsis is uncertain.

Balanced versus isotonic saline resuscitation-a systematic review and meta-analysis of randomized controlled trials in operation rooms and intensive care units

BACKGROUND

Fluid resuscitation is the cornerstone in treatment of shock, and intravenous fluid administration is the most frequent intervention in operation rooms and intensive care units (ICUs). The composition of fluids used for fluid resuscitation gained interest over the past decade, with recent focus on whether balanced solutions should be preferred over isotonic saline.

METHODS

Systematic review and meta-analysis of randomized controlled trials (RCTs) comparing fluid resuscitation with a balanced solution versus isotonic saline in adult patients in operation room or ICUs. Primary outcome was in-hospital mortality, secondary outcomes included occurrence of acute kidney injury (AKI) and need for renal replacement therapy (RRT).

RESULTS

The search identified 11 RCTs involving 2,703 patients; 8 trials were conducted in operation room and 3 in ICU. In-hospital mortality, as well as the occurrence of AKI and need for RRT was not different between resuscitation with balanced solutions versus isotonic saline, neither in operation room nor in ICU patients. Serum chloride levels, but not arterial pH, were significantly lower in patients resuscitated with balanced solutions.

CONCLUSIONS

Currently evidence insufficiently supports the use of balanced over isotonic saline for fluid resuscitation to improve outcome of operation room and ICU patients.