9 research outputs found
Gender-Specific Differences in Low-Dose Haloperidol Response for Prevention of Postoperative Nausea and Vomiting: A Register-Based Cohort Study
Postoperative nausea and vomiting (PONV) is one of the most common and distressing complications after general anesthesia and surgery, with young non-smoking females receiving postoperative opioids being high-risk patients. This register-based study aims to evaluate the effect of low-dose haloperidol (0.5 mg intravenously) directly after induction of general anesthesia to reduce the incidence of PONV in the postoperative anesthesiological care unit (PACU).Multivariable regression models were used to investigate the association between low-dose haloperidol and the occurrence of PONV using a patient registry containing 2,617 surgical procedures carried out at an university hospital.Haloperidol 0.5 mg is associated with a reduced risk of PONV in the total collective (adjusted odds ratio = 0.75, 95% confidence interval: [0.56, 0.99], p = 0.05). The results indicate that there is a reduced risk in male patients (adjusted odds ratio = 0.45, 95% confidence interval: [0.28, 0.73], p = 0.001) if a dose of 0.5 mg haloperidol was administered while there seems to be no effect in females (adjusted odds ratio = 1.02, 95% confidence interval: [0.71, 1.46], p = 0.93). Currently known risk factors for PONV such as female gender, duration of anesthesia and the use of opioids were confirmed in our analysis.This study suggests that low-dose haloperidol has an antiemetic effect in male patients but has no effect in female patients. A confirmation of the gender-specific effects we have observed in this register-based cohort study might have major implications on clinical daily routine
Effective spinless fermions in the strong coupling Kondo model
Starting from the two-orbital Kondo-lattice model with classical t_2g spins,
an effective spinless fermion model is derived for strong Hund coupling J_H
with a projection technique. The model is studied by Monte Carlo simulations
and analytically using a uniform hopping approximation. The results for the
spinless fermion model are in remarkable agreement with those of the original
Kondo-lattice model, independent of the carrier concentration, and even for
moderate Hund coupling J_H. Phase separation, the phase diagram in uniform
hopping approximation, as well as spectral properties including the formation
of a pseudo-gap are discussed for both the Kondo-lattice and the effective
spinless fermion model in one and three dimensions.Comment: Revtex4, 10 pages, 15 figures, typos correcte
Uniform hopping approach to the FM Kondo Model at finite temperature
We study the ferromagnetic Kondo model with classical corespins via unbiased
Monte-Carlo simulations and derive a simplified model for the treatment of the
corespins at any temperature. Our simplified model captures the main aspects of
the Kondo model and can easily be evaluated both numerically and analytically.
It provides a better qualitative understanding of the physical features of the
Kondo model and rationalizes the Monte-Carlo results, including the spectral
density A_k(omega) of a 1D chain with nearest neighbor Coulomb repulsion. By
calculating the specific heat and the susceptibility of systems up to size
16^3, we determine the Curie temperature of the 3D one-orbital double-exchange
model, which agrees with experimental values.Comment: 11 pages, 9 figures, RevTex4, additional references cite
Magnetic Polarons in the 1D FM Kondo Model
The ferromagnetic Kondo model with classical corespins is studied via
unbiased Monte-Carlo simulations. We show that with realistic parameters for
the manganites and at low temperatures, the double-exchange mechanism does not
lead to phase separation in one-dimensional chains but rather stabilizes
individual ferromagnetic polarons. Within the ferromagnetic polaron picture,
the pseudogap in the one-particle spectral function A_k(\omega) can easily be
explained. Ferromagnetic polarons also clear up a seeming failure of the
double-exchange mechanism in explaining the comparable bandwidths in the
ferromagnetic and paramagnetic phase. For our analysis, we extend a simplified
model, the finite temperature uniform hopping approach (UHA), to include
polarons. It can easily be evaluated numerically and provides a simple
quantitative understanding of the physical features of the ferromagnetic Kondo
model.Comment: 11 pages, 9 figures included, additional refs adde
Nonlinear covariate effects.
<p>Estimated nonlinear effects of anesthesia duration (A), intravenous sufentanil (B), remifentanil TCI total dosage (C), piritramide intravenous (D) and propofol infusion maximum rate (E). The solid black line visualizes the estimated effect (measured on log OR scale), the grey region corresponds to the 95% pointwise confidence interval for the estimated effect. The marks along the x-axis indicate the observed covariate values in the data.</p
Apfel scores.
<p>Relative frequency of patients with Apfel scores 0–4 in the haloperidol group and in the non-haloperidol group.</p