Pralidoxime-Induced Potentiation of the Pressor Effect of Adrenaline and Hastened Successful Resuscitation by Pralidoxime in a Porcine Cardiac Arrest Model

Effects of Sodium Nitroprusside Administered Via a Subdural Intracranial Catheter on the Microcirculation, Oxygenation, and Electrocortical Activity of the Cerebral Cortex in a Pig Cardiac Arrest Model

Background

Postischemic cerebral hypoperfusion has been indicated as an important contributing factor to secondary cerebral injury after cardiac arrest. We evaluated the effects of sodium nitroprusside administered via a subdural intracranial catheter on the microcirculation, oxygenation, and electrocortical activity of the cerebral cortex in the early postresuscitation period using a pig model of cardiac arrest.

Methods and Results

Twenty‐nine pigs were resuscitated with closed cardiopulmonary resuscitation after 14 minutes of untreated ventricular fibrillation. Thirty minutes after restoration of spontaneous circulation, 24 pigs randomly received either 4 mg of sodium nitroprusside (IT‐SNP group) or saline placebo (IT‐saline group) via subdural intracranial catheters and were observed for 5 hours. The same dose of sodium nitroprusside was administered intravenously in another 5 pigs. Compared with the IT‐saline group, the IT‐SNP group had larger areas under the curve for tissue oxygen tension and percent changes of arteriole diameter and number of perfused microvessels from baseline (all P<0.05) monitored on the cerebral cortex during the 5‐hour period, without severe hemodynamic instability. This group also showed faster recovery of electrocortical activity measured using amplitude‐integrated electroencephalography. Repeated‐measures analysis of variance revealed significant group–time interactions for these parameters. Intravenously administered sodium nitroprusside caused profound hypotension but did not appear to increase the cerebral parameters.

Conclusions

Sodium nitroprusside administered via a subdural intracranial catheter increased post–restoration of spontaneous circulation cerebral cortical microcirculation and oxygenation and hastened electrocortical activity recovery in a pig model of cardiac arrest. Further studies are required to determine its impact on the long‐term neurologic outcomes.

Cardiotoxicity of some pesticides and their amelioration

Pesticides are used to control pests that harm plants, animals, and humans. Their application results in the contamination of the food and water systems. Pesticides may cause harm to the human body via occupational exposure or the ingestion of contaminated food and water. Once a pesticide enters the human body, it may create health consequences such as cardiotoxicity. There is not enough information about pesticides that cause cardiotoxicity in the literature. Currently, there are few reports that summarized the cardiotoxicity due to some pesticide groups. This necessitates reviewing the current literature regarding pesticides and cardiotoxicity and to summarize them in a concrete review. The objectives of this review article were to summarize the advances in research related to pesticides and cardiotoxicity, to classify pesticides into certain groups according to cardiotoxicity, to discuss the possible mechanisms of cardiotoxicity, and to present the agents that ameliorate cardiotoxicity. Approximately 60 pesticides were involved in cardiotoxicity: 30, 13, and 17 were insecticides, herbicides, and fungicides, respectively. The interesting outcome of this study is that 30 and 13 pesticides from toxicity classes II and III, respectively, are involved in cardiotoxicity. The use of standard antidotes for pesticide poisoning shows health consequences among users. Alternative safe medical management is the use of cardiotoxicity-ameliorating agents. This review identifies 24 ameliorating agents that were successfully used to manage 60 cases. The most effective agents were vitamin C, curcumin, vitamin E, quercetin, selenium, chrysin, and garlic extract. Vitamin C showed ameliorating effects in a wide range of toxicities. The exposure mode to pesticide residues, where 1, 2, 3, and 4 are aerial exposure to pesticide drift, home and/or office exposure, exposure due to drinking contaminated water, and consumption of contaminated food, respectively. General cardiotoxicity is represented by 5, whereas 6, 7, 8 and 9 are electrocardiogram (ECG) of hypotension due to exposure to OP residues, ECG of myocardial infraction due to exposure to OPs, ECG of hypertension due to exposure to OC and/or PY, and normal ECG respectively.

Relationship of common hemodynamic and respiratory target parameters with brain tissue oxygen tension in the absence of hypoxemia or hypotension after cardiac arrest: A post-hoc analysis of an experimental study using a pig model

Brain tissue oxygen tension (PbtO2)-guided care, a therapeutic strategy to treat or prevent cerebral hypoxia through modifying determinants of cerebral oxygen delivery, including arterial oxygen tension (PaO2), end-tidal carbon dioxide (ETCO2), and mean arterial pressure (MAP), has recently been introduced. Studies have reported that cerebral hypoxia occurs after cardiac arrest in the absence of hypoxemia or hypotension. To obtain preliminary information on the degree to which PbtO2 is responsive to changes in the common target variables for PbtO2-guided care in conditions without hypoxemia or hypotension, we investigated the relationships between the common target variables for PbtO2-guided care and PbtO2 using data from an experimental study in which the animals did not experience hypoxemia or hypotension after resuscitation. We retrospectively analyzed 170 sets of MAP, ETCO2, PaO2, PbtO2, and cerebral microcirculation parameters obtained during the 60-min post-resuscitation period in 10 pigs resuscitated from ventricular fibrillation cardiac arrest. PbtO2 and cerebral microcirculation parameters were measured on parietal cortices exposed through burr holes. Multiple linear mixed effect models were used to test the independent effects of each variable on PbtO2. Despite the absence of arterial hypoxemia or hypotension, seven (70%) animals experienced cerebral hypoxia (defined as PbtO2 <20 mmHg). Linear mixed effect models revealed that neither MAP nor ETCO2 were related to PbtO2. PaO2 had a significant linear relationship with PbtO2 after adjusting for significant covariates (P = 0.030), but it could explain only 17.5% of the total PbtO2 variance (semi-partial R2 = 0.175; 95% confidence interval, 0.086-0.282). In conclusion, MAP and ETCO2 were not significantly related to PbtO2 in animals without hypoxemia or hypotension during the early post-resuscitation period. PaO2 had a significant linear association with PbtO2, but its ability to explain PbtO2 variance was small.