I like this paper for introducing a new concept to me. For years the critical care community has recognised the link between hyperglycaemia and mortality, leading to early recommendations of intensive insulin regimens subsequently shown not to be of benefit. Now it appears that the association between hyperglycaemia and mortality may be less relevant in patients with a normal lactate.
In a study of adult nondiabetic critically ill patients, hyperglycaemia had a significant association with increased mortality risk using simple univariate analysis. When they adjusted for concurrent hyperlactataemia however, hyperglycaemia was not significantly associated with increased mortality risk.
The authors discuss several known or postulated aspects of interplay between lactate and glucose in sepsis:
- Hyperlactataemia appears to inhibit glucose uptake by muscle cells and decrease activity of the GLUT-4 transporters
- Hyperlactataemia has also been shown to increase insulin resistance directly
- Glucose and lactate levels tend to be elevated simultaneously in severe sepsis at baseline.
- Experimentally it has been estimated that 45% of infused (radiolabelled) lactate is either converted into glucose via gluconeogenesis or is transformed into glycogen via the Cori cycle, representing a higher proportion of glucose formation from lactate than in nonseptic controls.
- It is possible that elevated glucose and lactate levels in sepsis both may be measures of the same phenomenon: glucose accumulates due to the sympathomimetic response to a systemic infection with increased catecholamine levels leading to increased activity of the Na+K+-ATPase, resulting in accumulation of adenosine diphosphate (ADP). Increased levels of ADP in turn augment glycogenolysis.
- Mitochondrial metabolism cannot meet the increased cellular energy needs of sepsis, resulting in accumulation of ADP and leading to cytosolic glycolysis and lactate production, even in an aerobic environment.
The augmented glycolysis of sepsis (and during adrenergic therapy such as epinephrine/adrenaline or albuterol/salbutamol) is one of the causes of a raised lactate to consider when applying the LACTATES mnemonic I like to use.
Hyperlactatemia affects the association of hyperglycemia with mortality in nondiabetic adults with sepsis
Acad Emerg Med. 2012 Nov;19(11):1268-75
[EXPAND Click for abstract]
BACKGROUND: Admission hyperglycemia has been reported as a mortality risk factor for septic nondiabetic patients; however, hyperglycemia’s known association with hyperlactatemia was not addressed in these analyses.
OBJECTIVES: The objective was to determine whether the association of hyperglycemia with mortality remains significant when adjusted for concurrent hyperlactatemia.
METHODS: This was a post hoc, nested analysis of a retrospective cohort study performed at a single center. Providers had identified study subjects during their emergency department (ED) encounters; all data were collected from the electronic medical record (EMR). Nondiabetic adult ED patients hospitalized for suspected infection, two or more systemic inflammatory response syndrome (SIRS) criteria, and simultaneous lactate and glucose testing in the ED were enrolled. The setting was the ED of an urban teaching hospital from 2007 to 2009. To evaluate the association of hyperglycemia (glucose > 200 mg/dL) with hyperlactatemia (lactate ≥ 4.0 mmol/L), a logistic regression model was created. The outcome was a diagnosis of hyperlactatemia, and the primary variable of interest was hyperglycemia. A second model was created to determine if coexisting hyperlactatemia affects hyperglycemia’s association with mortality; the main outcome was 28-day mortality, and the primary risk variable was hyperglycemia with an interaction term for simultaneous hyperlactatemia. Both models were adjusted for demographics; comorbidities; presenting infectious source; and objective evidence of renal, respiratory, hematologic, or cardiovascular dysfunction.
RESULTS: A total of 1,236 ED patients were included, and the median age was 77 years (interquartile range [IQR] = 60 to 87 years). A total of 115 (9.3%) subjects were hyperglycemic, 162 (13%) were hyperlactatemic, and 214 (17%) died within 28 days of their initial ED visits. After adjustment, hyperglycemia was significantly associated with simultaneous hyperlactatemia (odds ratio [OR] = 4.14, 95% confidence interval [CI] = 2.65 to 6.45). Hyperglycemia and concurrent hyperlactatemia were associated with increased mortality risk (OR = 3.96, 95% CI = 2.01 to 7.79), but hyperglycemia in the absence of simultaneous hyperlactatemia was not (OR = 0.78, 95% CI = 0.39 to 1.57).
CONCLUSIONS: In this cohort of septic adult nondiabetic patients, mortality risk did not increase with hyperglycemia unless associated with simultaneous hyperlactatemia. The previously reported association of hyperglycemia with mortality in nondiabetic sepsis may be due to the association of hyperglycemia with hyperlactatemia.
A meta-analysis attempts to quantify etomidate’s effect on mortality and adrenal suppression. Of course, we all know a meta-analysis can only be as reliable as the original data it’s analysing. I think editorialists Lauzier and Turgeon have a point with their statement:
“Given the widespread use of etomidate in the emergency room, we believe that a RCT designed to evaluate the safety of etomidate as a hypnotic agent for endotracheal intubation of patients with sepsis is not only ethical but also urgently warranted”
For a critique of the paper and subsequent discussion, check out the Academic Life in EM blog post by Brian Hayes
OBJECTIVE: To evaluate the effects of single-dose etomidate on the adrenal axis and mortality in patients with severe sepsis and septic shock.
DESIGN: A systematic review of randomized controlled trials and observational studies with meta-analysis.
SETTING: Literature search of EMBASE, Medline, Cochrane Database, and Evidence-Based Medical Reviews.
SUBJECTS: Sepsis patients who received etomidate for rapid sequence intubation.
MEASUREMENTS AND MAIN RESULTS: We conducted a systematic review of randomized controlled trials and observational studies with meta-analysis assessing the effects of etomidate on adrenal insufficiency and all-cause mortality published between January 1950 and February 2012. We only examined studies including septic patients. All-cause mortality served as our primary end point, whereas the prevalence of adrenal insufficiency was our secondary end point. Adrenal insufficiency was determined using a cosyntropin stimulation test in all studies. We used a random effects model for analysis; heterogeneity was assessed with the I statistic. Publication bias was evaluated with Begg’s test. Five studies were identified that assessed mortality in those who received etomidate. A total of 865 subjects were included. Subjects who received etomidate were more likely to die (pooled relative risk 1.20; 95% confidence interval 1.02-1.42; Q statistic, 4.20; I2 statistic, 4.9%). Seven studies addressed the development of adrenal suppression associated with the administration of etomidate; 1,303 subjects were included. Etomidate administration increased the likelihood of developing adrenal insufficiency (pooled relative risk 1.33; 95% confidence interval 1.22-1.46; Q statistic, 10.7; I2 statistic, 43.9%).
CONCLUSIONS: Administration of etomidate for rapid sequence intubation is associated with higher rates of adrenal insufficiency and mortality in patients with sepsis.
Etomidate is associated with mortality and adrenal insufficiency in sepsis: A meta-analysis Crit Care Med. 2012 Nov;40(11):2945-53
A small retrospective study suggests adrenal insufficiency is common in kids with septic shock, and that steroid administration in these children was associated with a decrease in vasoactive drug requirements.
INTRODUCTION: Adrenal insufficiency may be common in adults and children with vasopressor-resistant shock. We developed a protocolized approach to low-dose adrenocorticotropin testing and empirical low-dose glucocorticoid/mineralocorticoid supplementation in children with systemic inflammatory response syndrome and persistent hypotension following fluid resuscitation and vasopressor infusion.
HYPOTHESIS: We hypothesized that absolute and relative adrenal insufficiency was common in children with systemic inflammatory response syndrome requiring vasopressor support and that steroid administration would be associated with decreased vasopressor need.
METHODS: Retrospective review of pediatric patients with systemic inflammatory response syndrome and vasopressor-dependent shock receiving protocol-based adrenocorticotropin testing and low-dose steroid supplementation. The incidence of absolute and relative adrenal insufficiency was determined using several definitions. Vasopressor dose requirements were evaluated before, and following, initiation of corticosteroids.
RESULTS: Seventy-eight patients met inclusion criteria for systemic inflammatory response syndrome and shock; 40 had septic shock. Median age was 84 months (range, 0.5-295). By adrenocorticotropin testing, 44 (56%) had absolute adrenal insufficiency, 39 (50%) had relative adrenal insufficiency, and 69 (88%) had either form of adrenal insufficiency. Adrenal insufficiency incidence was significantly higher in children >2 yrs (p = .0209). Therapeutic interventions included median 80-mL/kg fluid resuscitation; 65% of patients required dopamine, 58% norepinephrine, and 49% dopamine plus norepinephrine. With steroid supplementation, median dopamine dose decreased from 10 to 4 μg/kg/min at 4 hrs (p = .0001), and median dose of norepinephrine decreased from 0.175 μg/kg/min to 0.05 μg/kg/min at 4 hrs (p = .039).
CONCLUSIONS: Absolute and relative adrenal insufficiency was prevalent in this cohort of children with systemic inflammatory response syndrome and vasopressor-dependent shock and increased with age. Introduction of steroids produced a significant reduction in vasopressor duration and dosage. Use of low-dose adrenocorticotropin testing may help further delineate populations who require steroid supplementation.
Incidence of adrenal insufficiency and impact of corticosteroid supplementation in critically ill children with systemic inflammatory syndrome and vasopressor-dependent shock
Crit Care Med. 2011 May;39(5):1145-50
Blogging has slowed a bit as I’ve been travelling to the UK and am running courses here all week.
Just in case you’re desperate to read something useful, I came across a guideline on The Management of Diabetic Ketoacidosis in Adults by the Joint British Diabetes Societies Inpatient Care Group
The guideline contain the following approaches:
- Measurement of blood ketones, venous (not arterial) pH and bicarbonate and their use as treatment markers
- Monitoring of ketones and glucose using bedside meters when available and operating within their quality assurance range
- Replacing ‘sliding scale’ insulin with weight-based fixed rate intravenous insulin infusion (IVII)
- Use of venous blood rather than arterial blood in blood gas analysers
- Monitoring of electrolytes on the blood gas analyser with intermittent laboratory confirmation
- Continuation of long acting insulin analogues (Lantus® or Levemir®) as normal
- Involvement diabetes specialist team as soon as possible
There is also a section on ‘Controversial Areas’, discussing such issues as bicarbonate therapy, rate of fluid therapy, and even 0.9% saline versus Hartmann’s (Ringer’s Lactate) solution, although this part was desperately disappointing, with the following bizarre excuse given for not recommending the latter:
“In theory replacement with glucose and compound sodium lactate (Hartmann’s solution) with potassium, would prevent hyperchloraemic metabolic acidosis, as well as allow appropriate potassium replacement. However, at present this is not readily available as a licensed infusion fluid.”
Apart from that, this appears to be an interesting and potentially useful document.
The Management of Diabetic Ketoacidosis in Adults
Joint British Diabetes Societies Inpatient Care Group
A thought provoking article in Critical Care Medicine outlines basic science, animal, and human studies that suggest oestrogen may have a protective effect in a wide range of critical illnesses from cardiac arrest to trauma to stroke. It urges clinical trials of sex hormones, some of which are underway. Regarding traumatic brain injury, the authors state: “To date, studied interventions to treat the effects of secondary injury, such as induced hypothermia or sedative-hypnotic coma, have had disappointing results… Clearly, EMS (or emergency department) infusion of a single IV bolus of estrogen, a therapy shown in the laboratory to be a strong, direct, easy-to-deliver antioxidant, antiapoptotic, and anti-inflammatory intervention, has a much better chance of decreasing the severity of injury.”
Bold? Let’s see if studies such as this one show this intervention to be so beneficial.
Rationale for routine and immediate administration of intravenous estrogen for all critically ill and injured patients
Critical Care Medicine. 38(10):S620-S629, October 2010
The International Society for Paediatric and Adolescent Diabetes (ISPAD) has published new comprehensive guidelines, including those for diabetic ketoacidosis.
• DKA is caused by either relative or absolute insulin deﬁciency.
• Children and adolescents with DKA should be managed in centers experienced in its treatment and where vital signs, neurological status and laboratory results can be monitored frequently
• Begin with ﬂuid replacement before starting insulin therapy.
• Volume expansion (resuscitation) is required only if needed to restore peripheral circulation.
• Subsequent ﬂuid administration (including oral ﬂuids) should rehydrate evenly over 48 hours at a rate rarely in excess of 1.5 – 2 times the usual daily maintenance requirement.
• Begin with 0.1 U/kg/h. 1 – 2 hours AFTER starting ﬂuid replacement therapy
• If the blood glucose concentration decreases too quickly or too low before DKA has resolved,
increase the amount of glucose administered. Do NOT decrease the insulin infusion
• Even with normal or high levels of serum potassium at presentation, there is always a total body deﬁcit of potassium.
• Begin with 40 mmol potassium/L in the infusate or 20 mmol potassium/L in the patient receiving ﬂuid at a rate >10 mL/kg/h.
• There is no evidence that bicarbonate is either necessary or safe in DKA.
• Have mannitol or hypertonic saline at the bedside and the dose to be given calculated beforehand.
• In case of profound neurological symptoms, mannitol should be given immediately.
• All cases of recurrent DKA are preventable.
Full guidelines available here
Other ISPAD guidelines available here