[Characteristics and impact of sedation, analgesia, and neuromuscular blockage in critical patients undergoing prolonged mechanical ventilation]

AIM

To describe use of sedatives, analgesics, and neuromuscular blockers (NMB) in patients undergoing long-term mechanical ventilation and to assess factors associated with their use and their association with mortality at 28 days.

DESIGN

Prospective observational multicenter cohort study.

SETTING

Thirteen intensive care units (ICU) in Chile.

PATIENTS

Patients undergoing mechanical ventilation for more than 48h. We excluded patients with neurological disorders, cirrhosis of the liver, chronic renal failure, suspected drug addiction, and early no resuscitation orders.

INTERVENTION

None.

MAIN MEASUREMENTS

Proportion of use and dosage of sedatives, analgesics, and NMB. Level of sedation observed (SAS). Variables associated with the Sedation Agitation Scale (SAS), use of sedatives, analgesics, and NMB. Multivariate logistic regression of variables associated to mortality at 28 days.

RESULTS

A total of 155 patients participated (60+/-18 years, 57% male, SOFA 7 [6-10], APACHE II 18 [15-22], 63% with sepsis, and 47% with acute lung injury/adult respiratory distress syndrome. The drugs most frequently used were midazolam (85%, 4 [1.9-6.8]mg/hr) and fentanyl (81%, 76 [39-140]microg/hr). NMB were administered at least 1 day in 30% of patients. SAS score was 1 or 2 in 55% of patients. There was an association between NMB use and mortality at 28 days, but it was not consistent in all the models of NMB evaluated.

CONCLUSIONS

Sedatives were frequently employed and deep sedation was common. Midazolam and fentanyl were the most frequently administered drugs. The use of NMB might be independently associated to greater mortality.

Fetoscopic release of umbilical cord amniotic band in a human fetus

Umbilical cord amniotic bands occur in approximately 10% of cases of amniotic band syndrome and are a well-known cause of fetal death. An unexpected amniotic band encircling the umbilical cord was diagnosed during a fetoscopic procedure to release a leg constriction. Both bands were released fetoscopically using a YAG laser. We report the first case of an amniotic band involving the umbilical cord diagnosed and released prenatally.

A novel NGFB point mutation: a phenotype study of heterozygous patients

OBJECTIVE

A family with neurological findings similar to hereditary sensory and autonomic neuropathy type V having a point mutation in the nerve growth factor beta (NGFB) gene was recently described. The homozygous genotype gives disabling symptoms. The purpose of the present study was to evaluate the symptoms in heterozygous patients.

METHODS

26 patients heterozygous for the NGFB mutation (12 men, mean age 50 (13-90) years) were examined clinically and answered a health status questionnaire, including the Michigan Neuropathy Screening Instrument (MNSI). 28 relatives (15 men, mean age 44 (15-86) years) without the mutation served as controls in the clinical examination part. 23 of the heterozygotes were examined neurophysiologically and six heterozygous patients underwent a sural nerve biopsy.

RESULTS

The heterozygous phenotype ranged from eight patients with Charcot arthropathy starting in adult age and associated with variable symptoms of neuropathy but without complete insensitivity to pain, anhidrosis or mental retardation, to 10 symptom free patients. There was no difference in MNSI between the young heterozygous cases (<55 years old) and the controls. Six of 23 heterozygous patients had impaired cutaneous thermal perception and 11 of 23 had signs of carpal tunnel syndrome. Sural nerve biopsies showed a moderate reduction of both small myelinated (Adelta) and unmyelinated (C) fibres. No apparent correlation of small fibre reduction to symptoms was found.

CONCLUSIONS

The NGFB mutation in its heterozygous form results in a milder disease than in homozygotes, with a variable clinical picture, ranging from asymptomatic cases to those with Charcot arthropathy appearing in adult age. Particularly age, but perhaps lifestyle factors also, may influence the development of clinical polyneuropathy.

High stability of yellow fever 17D-204 vaccine: A 12-year restrospective analysis of large-scale production

We have retrospectively analyzed 12 bulk lots of yellow fever vaccine Stamaril, produced between 1990 and 2002 and prepared from the same seed lot that has been in continuous use since 1990. All vaccine batches displayed identical genome sequence. Only four nucleotide substitutions were observed, compared to previously published sequence, with no incidence at amino-acid level. Fine analysis of viral plaque size distribution was used as an additional marker for genetic stability and demonstrated a remarkable homogeneity of the viral population. The total virus load, measured by qRT-PCR, was also homogeneous pointing out reproducibility of the vaccine production process. Mice inoculated intracerebrally with the different bulks exhibited a similar average survival time, and ratio between in vitro potency and mouse LD(50) titers remained constant from batch-to-batch. Taken together, these data demonstrate the genetic stability of the strain at mass production level over a period of 12 years and reinforce the generally admitted idea of the safety of YF17D-based vaccines.

Monocyte cytokine and costimulatory molecule expression in patients infected with Leishmania mexicana

Leishmania mexicana causes localized and diffuse cutaneous leishmaniasis. Patients with localized cutaneous leishmaniasis (LCL) develop a benign disease, whereas patients with diffuse cutaneous leishmaniasis (DCL) suffer from a progressive disease associated with anergy of the cellular response towards Leishmania antigens. We evaluated the production of the interleukins (IL) IL-12, IL-15, IL-18 and tumour necrosis factor-alpha (TNF-alpha) and the expression of the costimulatory molecules CD40, B7-1 and B7-2 in monocytes from LCL and DCL patients, stimulated in vitro with Leishmania mexicana lipophosphoglycan (LPG) for 18 h. LCL monocytes significantly increased TNF-alpha, IL-15 and IL-18 production, and this increase was associated with reduced amounts of IL-12. DCL monocytes produced no IL-15 or IL-18 and showed a decreasing tendency of TNF-alpha and IL-12 production as the severity of the disease increased. No difference was observed in the expression of CD40 and B7-1 between both groups of patients, yet B7-2 expression was significantly augmented in DCL patients. It remains to be established if this elevated B7-2 expression in DCL patients is cause or consequence of the Th2-type immune response that characterizes these patients. These data suggest that the diminished ability of the monocytes from DCL patients to produce cell-activating innate proinflammatory cytokines when stimulated with LPG is a possible cause for disease progression.

Extremity amniotic band syndrome in fetal lamb. I: An experimental model of limb amputation

OBJECTIVE

The objective of the study was to reproduce severe forms of extremity amniotic bands, which result in amputation or severe lesions.

STUDY DESIGN

Right limbs of 5 60-day gestational age pregnant sheep were ligated with silk suture at the infracondylar level. Left limbs were used for paired comparison. The limbs obtained from term fetuses were analyzed morphologically, radiologically, and histologically.

RESULTS

The ligated limbs showed an amputation or quasiamputation. Four extremities showed a necrotic pattern and 4 an edema pattern.

CONCLUSION

A model of severe extremity amniotic bands that reproduces the effect of the extremity amniotic bands in the human fetus was developed. Future applications of this new model could be an experimental study of in utero salvage of limbs affected with severe extremity amniotic bands in the ovine fetus.