Assessment of cardiotoxicity and plasma ropivacaine concentrations after serratus intercostal fascial plane block in an experimental model.

Serratus intercostal fascial plane block (SIFPB) has emerged as an alternative to paravertebral block in breast surgery. It involves the administration of high volumes and doses of local anesthetics (LA) that can potentially reach toxic levels. Ropivacaine is widely used in thoraco-fascial blocks; however, there is no information on the plasma concentrations attained after SIPFB and whether they are associated with cardiotoxicity. Plasma concentrations of ropivacaine and its electrophysiological effects were evaluated in eight pigs after bilateral SIFPB with ropivacaine in doses of 3 mg/kg. Plasma concentrations, electrophysiological and hemodynamic parameters were measured sequentially for the following 180 min until the end of the study. The area under the curve, the maximum plasma concentration (Cmax) and the time to reach Cmax (tmax) were calculated. The median arterial ropivacaine concentration Cmax was, 2.34 [1.40 to 3.74] µg/ml. The time to reach the highest concentration was 15 [10 to 20] min. Twenty-five percent of the animals had arterial concentrations above the lower limit concentration of ropivacaine for LA systemic toxicity (3.4 µg/ml). No alterations were observed in the electrophysiological or electrocardiographic parameters except for a prolongation of the QTc interval, from 489 ± 30 to 544 ± 44 ms (Δ11.38 ± 6%), P = 0.01. Hemodynamic parameters remained in the physiological range throughout the study. SIFPB with ropivacaine in doses of 3 mg/kg has reached potentially toxic levels, however, it has not been associated with adverse electrophysiological or hemodynamic effects.

Sodium bicarbonate reverts electrophysiologic cardiotoxicity of ropivacaine faster than lipid emulsions in a porcine model.

Ropivacaine has been described as a safer local anaesthetic (LA); however, serious cardiotoxic accidents have been reported. Intravenous-lipid-emulsion (ILE) therapy during LA intoxication seems to act as an antidote. Sodium bicarbonate is the standard treatment for sodium channel blocker drug toxicity. We compared both antidotes on the reversion of electrophysiologic toxicity induced by ropivacaine. Ropivacaine 5 mg kg-1 was administered in 24 pigs, and 3 min later, the animals received ILE: 1.5 ml kg-1  + 0.25 ml kg-1  min-1 (ILE group); sodium bicarbonate: 2 mEq kg-1  + 1 mEq kg-1  h-1 (NaHCO3 group); saline solution (CTL group). Electrophysiological parameters were evaluated for 30 min. The area under the curve (AUC) for the first 5 or 30 min was compared between groups. Ropivacaine induced a lengthening of the PR interval by 17% (P = 0.0001), His-ventricle-interval by 58% (P = 0.001), sinus QRS complex by 56% (P = 0.0001), paced QRS at 150 bpm by 257% (P = 0.0001), and at 120 bpm by 143% (P = 0.0001) in all groups. At 5 min after treatment, sinus QRS in the NaHCO3 group was shorter than that in the CTL group (AUCQRS5 , P = 0.003) or ILE group (AUCQRS5 , P = 0.045). During the first minute, seven of the animals in the NaHCO3 group vs. two in the ILE or 0 in the CTL group recovered more than 30% of the sinus QRS previously lengthened by ropivacaine (P = 0.003). Sodium bicarbonate reversed the electrophysiological toxicity of ropivacaine faster than ILE and control groups.

The effect of depressive symptoms on cognition in patients with fibromyalgia.

BACKGROUND: Fibromyalgia (FM) patients frequently complain of cognitive problems, but it remains unclear whether these cognitive complaints can be attributed to a dysfunction of the central nervous system or if they can be explained by other factors associated with the disease, such as depression, anxiety and sleep dysfunction. METHODS: One hundred and ten patients with FM were compared with thirty-three patients diagnosed with a depressive disorder (DD) and fifty healthy controls (HC). Several measures of attention and executive functions were used to make these comparisons and the patients were also asked to complete questionnaires on depression, anxiety and sleep quality. Univariate analyses of covariance (ANCOVA) were performed to identify and control confounders and multiple linear models were used to examine the effects of fibromyalgia and depression on cognitive measures. RESULTS: FM and HC differed significantly with respect to depression, anxiety and sleep dysfunction, whereas FM and DD did not differ in terms of symptoms of depression and anxiety. However, FM was associated with a worse quality of sleep than DD. Comparisons of cognitive performance between groups showed that short-term and working memory and inattention measures were only associated with symptoms of depression, whereas selective attention was associated with both depression and fibromyalgia, and processing speed, cognitive flexibility and inhibitory control showed a significant interaction between depression and fibromyalgia. Moreover, cognitive flexibility and inhibition abilities were specifically associated with FM. CONCLUSION: FM patients show a cluster of cognitive impairment in the attentional and executive domains, although some of the symptoms observed could be explained by the severity of the symptoms of depression, while others seem to depend on the effects of fibromyalgia. Implications of the findings for the understanding and management of cognitive impairment of FM patients are discussed.