The practice of medicine involves a large variety of myths. Often, they are perpetuated from generation to generation of physicians, and it is accepted that these practices are efficacious and appropriate.
The administration of multivitamins to chronic alcoholics — the proverbial banana bag — is one myth that has recently been successfully challenged. The assumption that alcoholics are malnourished in key nutrients (folic acid, B12, and thiamine, in particular) was thought reasonable, but the following study indicates that when the dispassionate searchlight of scientific inquiry is focused on the topic, it just isn't the case. It seems, at best, that patients may benefit from a little supplemental thiamine.
Vitamin Deficiencies in Acutely Intoxicated Patients in the ED
Li SF, et al
Am J Emerg Med
BACKGROUND: Patients presenting to the ED with acute alcohol intoxication are often presumed to be vitamin-deficient, although the chronicity of their alcohol use is uncertain. Such patients are often given a banana bag of IV fluids supplemented with multivitamins, thiamine, and magnesium.
METHODS: In this prospective observational study from Jacobi Medical Center in the Bronx, levels of vitamin B12, folate, and thiamine were measured in 75 patients 19 to 78 (mean 46, 19% female) presenting to the ED with acute alcohol intoxication.
RESULTS: Blood alcohol levels ranged between 23 mg/dL and 560 mg/dL, and were below 100 mg/dL in 11 percent, above 200 mg/dL in 78 percent, and above 400 mg/dL in 16 percent. The mean vitamin B12 level was 603 ng/L (normal, 200–730 ng/L), and the mean folate level was 14 mcg/L (normal, 2.8–13.5 mcg/L). No patient had a vitamin B12 or folate level below normal limits. The mean thiamine level in the 39 patients in whom it was tested was 130 nmol/L (normal, 87–280 nmol/L). Thiamine levels were below the normal range in six patients, but were largely borderline low (52–82 nmol/L overall), and none of the six patients exhibited signs or symptoms of thiamine deficiency. No patient had evidence of megaloblastic anemia.
CONCLUSIONS: No patients with acute alcohol intoxication had vitamin B12 or folate levels below the normal range, and few had low thiamine levels, of uncertain clinical significance, which do not support routine administration of multivitamins.
CPAP for Prehospital Care
Reports of failure rates of intubation in the field and worse yet unrecognized intubation of the esophagus are distressing. It would appear that some intermediary, noninvasive technique may be useful to support ventilation in cases that don't clearly need intubation but in which respiratory support would be beneficial.
The first paper demonstrated the successful use of prehospital CPAP in patients with respiratory distress. This is another study in which the results are so positive one wonders if they are too good to be true. Given the large number of studies of CPAP that demonstrate positive results, it would seem that providing this technique to paramedics would be a reasonable approach.
The second paper suggests CPAP as an alternative to adrenergics and steroids for bronchiolitis in infants. The literature has repeatedly noted that adrenergics and steroids, though effective in asthma, are not particularly good for bronchiolitis. A small prospective French study nicely demonstrated that CPAP was effective in avoiding intubation and was not associated with barotrauma. Although data on a larger group of patients would be nice given the limited therapeutic options, it appears that a trial of nasal CPAP would be reasonable in infants with significant respiratory distress caused by bronchiolitis.
Out-of-Hospital Continuous Positive Airway Pressure Ventilation versus Usual Care in Acute Respiratory Failure: A Randomized Controlled Trial
Thompson J, et al
Ann Emerg Med
BACKGROUND: Noninvasive ventilation has been reported to be a useful method to avoid endotracheal intubation in patients with respiratory distress, but its prehospital application has not been widely studied.
METHODS: In this prospective, controlled study from Dalhousie University in Canada, 69 patients with severe respiratory distress who were managed by paramedics were randomized to prehospital management with continuous positive airway pressure (CPAP) administered via facemask or usual care (beginning with bag-valve-mask ventilation).
RESULTS: The two groups had similar baseline characteristics including median age (about 70), oxygen saturation (75% in the usual care group and 82% in the CPAP group), and prehospital clinical diagnoses (ED diagnoses included congestive heart failure, COPD, and asthma, with some patients having multiple diagnoses). Rates of the primary outcome (intubation during the total episode of care) were 20 percent in the CPAP group and 50 percent in the usual care group. The mortality rate was 14 percent in the CPAP group and 35 percent in the usual care group. No patient randomized to CPAP underwent intubation in the field. In the usual care group, nine patients were intubated in the field (four of whom died), and two had unsuccessful intubation attempts.
CONCLUSIONS: In this small study, application of CPAP in the field by trained paramedics for the management of patients with severe respiratory distress was associated with a reduced need for intubation and reduced mortality.
Nasal Continuous Positive Airway Pressure Decreases Respiratory Muscles Overload in Young Infants with Severe Acute Viral Bronchiolitis
Cambonie G, et al
Intensive Care Med
BACKGROUND: Infants requiring ICU admission for RSV bronchiolitis exhibit severe airway obstruction, increased respiratory resistance, air trapping, and decreased compliance, with an excessive load on susceptible respiratory muscles.
METHODS: This prospective French study examined the effect of nasal continuous positive airway pressure (nCPAP) delivered via a system designed for young infants on the modified Woods Clinical Asthma Score (m-WCAS) in 12 infants below 3 months admitted to the PICU for RSV bronchiolitis. The five-item m-WCAS assigns a score of 0–2 for each of cyanosis, inspiratory breath sounds, expiratory wheezing, use of accessory muscles, and cerebral function, and a total score of five or higher is felt to reflect severe respiratory distress.
RESULTS: At baseline the mean m-WCAS was 5.3, and inspiratory and expiratory times were essentially identical. By one hour after initiation of nCPAP, the mean m-WCAS had decreased to 3.1, and transcutaneous CO2 decreased from 64 to 54 mmHg. There was a statistical decrease in inspiratory time and an increase in expiratory time, as well as 53 to 59 percent in measures of inspiratory effort and expiratory muscle activity. Similar patterns were observed at six hours. The mean duration of nCPAP was 135 hours, and none of the infants developed complications such as barotrauma, exhibited clinical deterioration, or required intubation.
CONCLUSIONS: The authors of this small study suggest that a course of nCPAP in infants with severe respiratory distress due to RSV bronchiolitis can decrease respiratory effort and improve signs and symptoms.
Etomidate for RSI?
There is a continuing controversy about etomidate for rapid sequence intubation in trauma patients. Use of this drug has been associated with depressed levels of corticosteroids, and experts worry this may be potentially harmful. This study puts the final nail in the coffin of this drug in trauma patients. Not only did the study nicely demonstrate a clear-cut reduction in steroid levels (and a depressed response to ACTH stimulation), but clinical outcomes were markedly different (so different that one wonders whether the results of this study are almost too dramatic to be true). In any case, it seems until there is compelling evidence to the contrary, etomidate should be avoided in trauma patients.
Adrenal Suppression Following a Single Dose of Etomidate for Rapid Sequence Induction: A Prospective Randomized Study
Hildreth AN, et al
BACKGROUND: Etomidate has some advantages for rapid sequence intubation (RSI), but some studies have reported transient suppression of adrenocortical function after a single dose. The clinical consequences in trauma patients are uncertain.
METHODS: In this prospective study from the University of Tennessee, 30 adult trauma patients 18 to 85 (mean 42.6, 63% male) who required RSI and mechanical ventilation within 48 hours after injury were randomized to IV succinylcholine with etomidate or fentanyl plus midazolam. Serum cortisol levels were measured before and four to six hours after RSI and after an ACTH stimulation test.
RESULTS: The two groups had similar mechanisms and severity of injury (90% blunt trauma), and average baseline cortisol levels (31 mcg/dL in etomidate group, 27 mcg/dL in control). The postintubation cortisol level was significantly lower in the etomidate group (18 mcg/dL vs. 28 mcg/dL), as was the average increase in cortisol after ACTH stimulation (4.2 mcg/dL vs. 11.2 mcg/dL). The etomidate group received more IV fluids than controls during the first 24 hours (7.2 L vs. 5.0 L), and significantly more packed red blood cells (4.0 vs. 0.6 units) and fresh frozen plasma (2.94 vs. 0.33 units). The etomidate group had a significantly longer duration of ICU stay (8.1 vs. 3.0 days), mechanical ventilation (6.3 vs. 1.5 days), and hospitalization (13.9 vs. 6.4 days). Two patients required vasopressors, two required decompression of abdominal compartment syndrome, two died, and all belonged to the etomidate group.
CONCLUSIONS: In view of their findings, the authors recommend the use of other drugs as first-line RSI agents in trauma patients.