Intravenous Infusion Of Nitroglycerin Research Articles

Controlled Hypotension During Functional Endoscopic Sinus Surgery (FESS) - A Comparative Evaluation Between Esmolol and Nitroglycerine

Background: Intraoperative bleeding is a frequent complication in functional endoscopic sinus surgery (FESS). Controlled hypotension is a useful technique for enhancing the surgical field and reducing operative blood loss. Nitrovasodilators and beta receptor antagonists are effective options for regulated hypotensive anaesthesia during FESS. We assessed the efficacy of esmolol and nitroglycerine for controlled hypotension in subjects undergoing FESS. Methods: A source of 64 participants undergoing elective FESS, were randomly allocated to group N (n=32), which got an intravenous Nitroglycerin infusion at 5–10 µg/kg/min, and group E (n=32), which received an initial bolus of 500 mcg/kg of intravenous esmolol over 30 seconds. Hemodynamic parameters were measured and the visibility of the surgical field was assessed using the average category scale (ACS). Result: In groups N and E, the mean surgical duration was 113.5 minutes and 102.34 minutes, respectively, and the mean operative blood loss was 188.5 ml and 173.7 ml. The esmolol group experienced a rapid decline in heart rate, and there was a statistically significant difference in mean SBP, DBP, and MAP across the study groups. At the 10-min, the majority of cases displayed scores of 3 in group E and 4 in group N. In the esmolol group, there was a significant difference between the hypotensive phase and the hemodynamic measures (p<0.05). Conclusion: Nitroglycerine and esmolol were effective in controlling hypotension. However, esmolol was superior in controlling the operative bleeding, surgical duration, enhanced surgical field visibility, and absence of reflex tachycardia compared to nitroglycerine

Effects of nitroglycerin combined with continuous regional arterial infusion on severe acute pancreatitis, triglyceride, inflammatory factors and prognosis

Abstract Background: To evaluate the effects of nitroglycerin combined with continuous regional arterial infusion (CRAI) on severe acute pancreatitis (SAP), triglyceride (TG), inflammatory factors and prognosis. Methods: SAP patients were randomly divided into control and observation groups (n=169). The control group was treated with intravenous infusion of nitroglycerin once daily for 2 d, while the observation group was treated with nitroglycerin combined with CRAI for 7 d. Their hospitalization time, abdominal pain relief time, abdominal distension relief time and intestinal function recovery time were recorded. The levels of inflammatory factors, and TG were measured. Their liver and kidney functions, hemorheological indices, prognosis, and adverse reactions were evaluated. Results: The observation group had significantly shorter hospitalization time, abdominal pain relief time, abdominal distension relief time, and intestinal function recovery time than those of the control group (P<0.05). After treatment, the levels of interleukin-6, tumor necrosis factor-alpha, endothelin, thromboxane A2 and TG significantly decreased in contrast with those before treatment in both groups, especially in the observation group (P<0.05). The hemorheological indices were significantly improved after treatment compared with those before treatment in both groups, and the observation group had better indices (P<0.05). The Acute Physiology and Chronic Health Evaluation-II score declined significantly in both groups after treatment, and the observation group had a more obvious decrease (P<0.05). During follow-up, similar incidence rates of adverse reactions were observed for both groups (P>0.05). Conclusion: Nitroglycerin combined with CRAI is prominently effective for treating SAP, which can facilitate the health recovery and reduce the incidence of microcirculation disturbance-induced adverse events such as organ failure.

Cerebral Oximetry-Monitored Nitroglycerin Infusion and Tissue Perfusion during Rewarming of Cardiopulmonary Bypass in Cardiac Surgery: A Prospective Randomized Trial.

Background: Nitroglycerin facilitates microcirculation and oxygen delivery through vasodilation. The purpose of this study was to clarify the effects of nitroglycerin-induced vasodilation and potential hypotension on tissue perfusion under cerebral oximetry monitoring during rewarming in cardiopulmonary bypass. Methods: Elective cardiac surgical patients were randomly assigned to either a nitroglycerin group (n = 32) with an intravenous infusion of 1–5 mcg/kg/min or a control group (n = 31) with 0–0.1 mcg/kg/min infusion, since the initiation of rewarming. Perioperative arterial blood gas data were collected in addition to hemodynamic variables, cerebral oximetry values, urine output, and postoperative outcomes. Results: Nearly one-fifth (6/32) of patients in the nitroglycerin group experienced transient (≤5 min) profound hypotension (mean arterial blood pressure ≤40 mmHg) after the initiation of infusion. There were no significant differences between groups in terms of perioperative levels of cerebral oximetry, cardiac index, plasma glucose, lactate, bicarbonate, base excess, or post-bypass activated coagulation time. In the nitroglycerin group, urine output was nonsignificantly higher during cardiopulmonary bypass (p = 0.099) and within 8 h after surgery (p = 0.157). Perioperative transfused blood products, postoperative inotropic doses, extubation time, and intensive care unit stay were comparable for the two groups. Conclusions: Initiation of intravenous nitroglycerin infusion (at 1–5 mcg/kg/min) during rewarming in hypothermic cardiopulmonary bypass resulted in transient profound hypotension in one-fifth of patients and did not improve perioperative cerebral oxygenation, tissue perfusion, and coagulation in cardiac surgery.

Areas of cerebral blood flow changes on arterial spin labelling with the use of symmetric template during nitroglycerin triggered cluster headache attacks

BackgroundCluster headache is a rare, strictly unilateral, severe episodic primary headache disorder. Due to the unpredictable and episodic nature of the attacks, nitroglycerin has been used to trigger attacks for research purposes to further our understanding of cluster headache pathophysiology. ObjectivesWe aimed to identify regions of significant cerebral blood flow (CBF) changes during nitroglycerin triggered cluster headache attacks, using MRI with arterial spin labelling (ASL). MethodsThirty-three subjects aged 18–60 years with episodic and chronic cluster headache were recruited and attended an open clinical screening visit without scanning to receive an intravenous nitroglycerin infusion (0.5 μg/kg/min over 20 min). Those for whom nitroglycerin successfully triggered a cluster headache attack, were invited to attend two subsequent scanning visits. They received either single-blinded intravenous nitroglycerin (0.5 μg/kg/min) or an equivalent volume of single-blinded intravenous 0.9% sodium chloride over a 20-minute infusion. Whole-brain CBF maps were acquired using a 3 Tesla MRI scanner pre-infusion and post-infusion. As cluster headache is a rare condition and purely unilateral disorder, an analysis strategy to ensure all the image data corresponded to symptomatology in the same hemisphere, without losing coherence across the group, was adopted. This consisted of spatially normalising all CBF maps to a standard symmetric reference template before flipping the images about the anterior-posterior axis for those CBF maps of subjects who experienced their headache in the right hemisphere. This procedure has been employed in previous studies and generated a group data set with expected features on the left hemisphere only. ResultsTwenty-two subjects successfully responded to the nitroglycerin infusion and experienced triggered cluster headache attacks. A total of 20 subjects completed the placebo scanning visit, 20 completed the nitroglycerin scanning visit, and 18 subjects had completed both the nitroglycerin and placebo scanning visits. In a whole-brain analysis, we identified regions of significantly elevated CBF in the medial frontal gyrus, superior frontal gyrus, inferior frontal gyrus and cingulate gyrus, ipsilateral to attack side, in CBF maps acquired during cluster headache attack; compared with data from the placebo session. We also identified significantly reduced CBF in the precuneus, cuneus, superior parietal lobe and occipital lobe contralateral to the attack side. Of particular interest to this field of investigation, both the hypothalamus and ipsilateral ventral pons showed higher CBF in a separate region of interest analysis. ConclusionOur data demonstrate that severe cluster headache leads to significant increases in regional cerebral perfusion, likely to reflect changes in neuronal activity in several regions of the brain, including the hypothalamus and the ventral pons. These data contribute to our understanding of cluster headache pathophysiology; and suggest that non-invasive ASL technology may be valuable in future mechanistic studies of this debilitating condition.

Safety and Feasibility of Prehospital Treatment of Acute Pulmonary Edema with Intravenous Bolus Nitroglycerin

Objective Prompt afterload reduction with high dose nitrates remains the cornerstone of treatment for decompensated heart failure with acute pulmonary edema (APE). Nitrate therapy in the prehospital setting is often limited to relatively low doses of sublingual nitroglycerin (NTG), which has poor bioavailability and is challenging to administer with concurrent use of non-invasive ventilation. Conversely, treatment in the Emergency Department typically consists of high doses of nitroglycerin, either by continuous intravenous (IV) infusion or by IV bolus (IVB NTG). A growing body of evidence suggests the safety and efficacy of large doses of IVB NTG in the hospital and prehospital settings. In this study, we assessed the safety and effectiveness of a prehospital bundle of care, which included IVB NTG followed by maintenance IV infusion of NTG for the treatment of decompensated heart failure with acute pulmonary edema. Methods This is a retrospective chart review of patients who received IVB NTG for decompensated heart failure with APE between May 1, 2019 and January 31, 2020 in a large, geographically diverse EMS system in Minnesota and Wisconsin. Inclusion criteria for treatment under this protocol included a working diagnosis of APE, a systolic blood pressure ≥120 mmHg and SpO2 ≤93% following 0.8 mg of SL NTG. Treatment consisted of a 400-mcg IV bolus of NTG, repeated every 2 minutes as needed during transport if SBP ≥120 mmHg. For transport times ≥10 minutes, an intravenous infusion of NTG was initiated at 80 mcg/min and titrated as needed to improve symptoms. Hypotension was defined as a systolic blood pressure ≤ 90 mmHg or a MAP ≤ 65 mmHg. Results During the study period, 45 patients were treated with IVB NTG. 25 patients were treated with IVB NTG alone. The median (IQR) total bolus dose was 400 mcg (400-1200 mcg). 20 patients were treated with a NTG infusion following IVB NTG. The median (IQR) infusion dose was 80 mcg/min (80-100 mcg/min). For all patients, the initial median (systolic IQR) blood pressure was 191/113 mmHg (169-217), 5 minutes following IVB NTG was 158/94 mmHg (141-178), and on arrival to the ED was 152/89 mmHg (129-172). 5 minutes after the initial dose of IVB NTG, there was an increase in median (IQR) oxygen saturation (SpO2) to 92% (88-96) from an initial reading of 88% (78-93). Median (IQR) SpO2 at hospital arrival was 94% (90-98). Median (IQR) transport time was 14 minutes (8.5-19). One episode of transient hypotension occurred during EMS transport and resolved without intervention. There were no cases requiring prehospital advanced airway management in this series. Conclusion Patients treated with IVB NTG by paramedics for APE had reduction in blood pressure and improvement in SpO2compared to their original presentation. There was one instance of transient hypotension that resolved without intervention en route. There were no cases requiring advanced airway management.

A Comparative Study between Nitroglycerin and Magnesium Sulfate during Shoulder Arthroscopic Surgery in the Beach Chair Position

AbstractBackground: This study was designed to compare the efficacy of intravenous infusion of nitroglycerin versus mag-nesium sulfate for controlled hypotensive anesthesia during arthroscopic shoulder surgery in Beach Chair Position (BCP).Aim of Study: To compare the efficacy of nitroglycerin versus magnesium sulfate in inducing deliberate hypotension and satisfactory surgical field in patients undergoing arthro-scopic shoulder surgery.Material and Methods: Fourty patients scheduled for arthroscopic shoulder surgery under general anesthesia in BCP, randomly assigned into two equal groups, nitroglycerin group (NTG group, n=20) received infusion of 0.5-5μg/kg/min and magnesium group (Mg group, n=20) received 40mg/kg, as slow bolus before induction in 100mL saline solution over 10min then 15mg/kg/h by infusion during the operation to achieve a mean arterial blood pressure (MAP) of about 50 to 65mmHg.Results: Controlled hypotension was achieved in both groups. There was no significant difference in MAP between two groups in first 30mins after infusion then magniseum group produced significantly lower MAP values till stopping of infusion. Heart Rate (HR) was significantly lower in mg group compared with the NTG group. More patients required fentanyl consumption intraoperative (p<0.0001) and frequent administration of rocuronium (p=0.001) in NTG group. How-ever, there was longer extubation time and recovery time in Mg group compared with the NTG group. Bleeding score was insignificantly lower in Mg group and surgeon's satisfaction score was significantly better (p=0.035) in the Mg group.Conclusions: Nitroglycerin and magnesium sulfate can effective in achieving hypotensive anesthesia during arthro-scopic shoulder surgery. However, MgSO4 provide a favorable surgical field condition and better surgeon's satisfaction.

Altered activity in the nucleus raphe magnus underlies cortical hyperexcitability and facilitates trigeminal nociception in a rat model of medication overuse headache

BackgroundThe pathogenesis of medication overuse headache (MOH) involves hyperexcitability of cortical and trigeminal neurons. Derangement of the brainstem modulating system, especially raphe nuclei may contribute to this hyperexcitability. The present study aimed to investigate the involvement of the nucleus raphe magnus (NRM) in the development of cortical and trigeminal hyperexcitability in a rat model of MOH.ResultsChronic treatment with acetaminophen increased the frequency of cortical spreading depression (CSD) and the number of c-Fos-immunoreactive (Fos-IR) neurons in the trigeminal nucleus caudalis (TNC). In the control group, muscimol microinjected into the NRM increased significantly the frequency of CSD-evoked direct current shift and Fos-IR neurons in the TNC. This facilitating effect was not found in rats with chronic acetaminophen exposure. In a model of migraine induced by intravenous systemic infusion of nitroglycerin (NTG), rats with chronic exposure to acetaminophen exhibited significantly more frequent neuronal firing in the TNC and greater Fos-IR than those without the acetaminophen treatment. Muscimol microinjection increased neuronal firing in the TNC in control rats, but not in acetaminophen-treated rats. The number of Fos-IR cells in TNC was not changed significantly.ConclusionChronic exposure to acetaminophen alters the function of the NRM contributing to cortical hyperexcitability and facilitating trigeminal nociception.

Fenômeno de no-re ow refratário. Mantenha a calma e observe!

ABSTRACT Risk awareness of no-reflow is mandatory, especially in patients with cardiovascular risk factors, long door-to-balloon time, and in the presence of angiographic evidence of a large thrombus burden. Some preventive strategies have been described. Nevertheless, in clinical practice, is difficult to avoid no-reflow. Interventional cardiologists have no guidelines or recommendations for this situation. We suggest that a conservative management with dual antiplatelet therapy and slow intravenous infusion of nitroglycerine over 12 to 24 hours and abciximab, followed by deferred [...]

Comparison between Phentolamine and Nitroglycerin for Controlled Hypotension during Functional Endoscopic Sinus Surgery

Background: Intraoperative bleeding is one of the most common complications in Functional endoscopic sinus surgery. Controlled hypotension is a method to minimize surgical blood loss and enhance the operative field visibility. The objective of this study was to compare the efficacy of controlled hypotensive anesthesia with intravenous infusion of phentolamine versus nitroglycerin as regarding intraoperative blood loss and hemodynamic stability. Methods: This current randomized study enrolled 30 patients candidate for Functional endoscopic sinus surgery at Beni-suef university hospital, in 2 equal groups receiving either 0.5 to 10 μg/kg/minute nitroglycerin or 0.1 to 2 mg/minute phentolamine to achieve a mean arterial blood pressure (MAP) of about 50 to 65 mmHg. Mean arterial blood pressure, amount of blood loss and the quality of surgical field using the 0-5 point bleeding scale were recorded. Results: Based on the current study findings, the two drugs produced the desired hypotension on the same time point; there were no significant differences between the study groups regarding the volume of bleeding and operative field visibility. Conclusions: Nitroglycerin and Phentolamine are safe, efficient and might be advisable option for deliberate hypotensive anesthesia throughout Functional endoscopic sinus surgery. Phentolamine can be a good alternative to Nitroglycerin in reduction of MAP during this procedure.

Acute myocardial infarction associated with right bundle branch block and changeable trifascicular block: a case report

Rationale: Acute myocardial infarction in the presence of right bundle branch block. Patient concerns: A 70-year-old, male heavy smoker presented with angina and hypertension. Interventions: Electrocardiography, intravenous nitroglycerin infusion, intravenous streptokinase infusion. Diagnosis: Acute myocardial infarction in the presence of with changeable trifascicular heart block. Outcomes: Dramatic clinical improvement with electrocardiographic ST-segment (whether elevation or reciprocal ST-depression) resolution. Lessons: Acute myocardial infarction may be associated right bundle branch block. Accompanied trifascicular heart block had pre-streptokinase left anterior fascicular block with left axis deviation and post-streptokinase left posterior fascicular block with right axis deviation.

Role of gabapentin in controlled hypotension for nasal surgeries

Background Providing bleeding control is critically important when microsurgical techniques are used. A mild bleeding can complicate the working in surgical field in nasal surgery so, a bloodless surgical field should be provided. For that purpose, the anesthesiologists should use controlled hypotension anesthetic technique. The aim of this study was to investigate the hypotensive and analgesic effects of gabapentin if combined with nitroglycerin infusion for conduction of hypotensive anesthesia in nasal surgeries. Patients and methods The present study was carried out at El-Zahraa hospital, Al Azhar University on 40 patients ASA I and II were randomly assigned into two equal groups (n=20). Gabapentin nitroglycerin (GN) group: patients received 1200 mg gabapentin orally 2 h preoperatively. Nitroglycerin placebo group (N): patients received placebo tablet orally 2 h preoperatively. Intravenous nitroglycerin infusion started and titrated for all 40 patients according to the target hypotensive condition (mean arterial pressure range between 55–65 mmHg and heart rate between 60–75 b/min). Intraoperative hemodynamic changes in the form of heart rate (HR) and mean arterial pressure (MAP) were recorded; the total nitroglycerin dose required was recorded; blood loss and quality of surgical field were assessed. Also, visual analog scale (VAS) for pain assessment and total amount of morphine used within 12 postoperative hours were detected for each group. Results The results showed that the heart rate and the mean arterial pressure were significantly lower in the GN group compared to N group. The total dose of intraoperative nitroglycerin was significantly lower in the GN group compared to N group. GN group provides the lower amount of blood loss and better surgical field exposure compared to N group. The visual analog scale (VAS) values was significantly lower at 30 min and 4 h post-operative while non-significant difference at 1 and 6 h postoperative in the GN group compared with N group. There was a significantly lower in the total morphine consumption for GN group compared to N group. Conclusion Preoperative oral gabapentin (1200 mg) augments the hypotensive effect of nitroglycerin as it provides dryness of surgical field associated with lower infusion rate of nitroglycerin. Also, it has better analgesic effect with lower narcotic consumption during controlled hypotensive anesthesia for nasal surgeries when compared to the administration of nitroglycerin alone.

Perioperative diltiazem or nitroglycerin in on-pump coronary artery bypass: A systematic review and network meta-analysis.

BackgroundArterial graft spasm is a severe complication after coronary artery bypass graft (CABG). Among numerous potential antispasmodic agents, systemic application of diltiazem and nitroglycerin had been investigated most frequently over the past three decades. However, it remains inconclusive if either or both agents could improve patient outcomes by preventing graft spasm when applied perioperatively, and, if so, which one would be a better choice. The current systematic review and network meta-analysis aims to summarize the data from all available randomized clinical trials of perioperative continuous intravenous infusion of diltiazem and/or nitroglycerin in patients undergoing on-pump CABG in order to define and compare their roles in graft spasm prevention and their impacts on perioperative outcomes.MethodsWe searched Ovid Medline, PubMed, CINAHL, Google Scholar and Cochrane Center for randomized controlled trials that reported outcome effects of perioperative continuous intravenous infusion of diltiazem and/or nitroglycerin in patients undergoing elective on-pump CABG. Conventional meta-analyses were conducted to evaluate the pairwise comparisons (diltiazem vs. placebo; nitroglycerin vs. placebo; diltiazem vs. nitroglycerin) on perioperative outcomes. Network meta-analyses were implemented to compare the three regimens through direct and indirect comparison.ResultsTwenty-seven studies involving 1,660 patients were included. Pairwise and network meta-analyses found no significant difference in mortality among the groups. There are four studies that reported blood flow measurements of internal mammary artery grafts intraoperatively after dissecting or immediately after distal anastomosis while patients were on continuous intravenous infusion of diltiazem and nitroglycerin. Although insufficient for data synthesis, the measured results from all four studies suggest that both diltiazem and nitroglycerin significantly increased blood flow of arterial grafts compared to placebo. For other perioperative outcomes, compared to diltiazem, patients that received nitroglycerin had higher odds of postoperative atrial fibrillation (OR = 2.67, 95% CI: 1.15 to 6.24) and higher peak serum cardiac enzymes. Patients that received placebo had higher odds of atrial fibrillation (OR = 3.00, 95% CI: 1.18 to 7.63) and lower odds of requiring inotrope support (OR = 0.19, 95% CI: 0.04 to 0.73) compared to diltiazem. Data from the network meta-analysis indicated that diltiazem had significantly lower odds of postoperative atrial fibrillation compared to nitroglycerin (OR = 0.39, 95% CI: 0.18 to 0.85). In fact, the rank from highest to lowest rates of postoperative atrial fibrillation was placebo>nitroglycerin>diltiazem. The rank from highest to lowest odds of requiring inotropic support is nitroglycerin> diltiazem>placebo. However, placebo had significantly higher odds of postoperative myocardial infarction than diltiazem (OR = 4.51, 95% CI: 1.34 to 15.25). The rank from highest to lowest odds of postoperative myocardial infarction, transient cardiac ischemic event and atrial fibrillation is placebo>nitroglycerin>diltiazem.ConclusionCompared to nitroglycerin and placebo, perioperative continuous intravenous infusion of diltiazem had stronger protective effects against postoperative ischemic cardiac injuries and atrial fibrillation although patients may need more inotropic support. The increased blood flow from diltiazem use in arterial grafts may potentially contribute to the drug’s outcome benefits.

Pharmacodynamic interaction between intravenous nitroglycerin and oral sacubitril/valsartan (LCZ696) in healthy subjects.

Sacubitril/valsartan (LCZ696) and nitroglycerin share the second messenger cGMP and lower blood pressure. Given the potential for co-administration of both drugs in patients with heart failure, this study was designed to investigate the potential for a pharmacodynamic drug interaction affecting blood pressure. In this double-blind, placebo-controlled, randomised, crossover study, 40 healthy subjects received sacubitril/valsartan 200mg bid (97/103mg bid) or placebo for 5days. Two hours after the morning dose of sacubitril/valsartan or placebo on day 5, subjects received intravenous nitroglycerin infusion at increasing doses up to 40μg/min or placebo. Serial measurements of blood pressure (BP), heart rate, biomarkers and sacubitril/valsartan pharmacokinetics were conducted. Administration of nitroglycerin alone led to a dose- and time-dependent decrease in supine systolic BP (SBP) and diastolic BP (DBP) which was similar when nitroglycerin was co-administered with sacubitril/valsartan. At the highest dose of nitroglycerin, the mean (95% CI) decrease from baseline of SBP/DBP was 19.54 (- 21.99, - 17.09)/12.38 (- 13.85, - 10.92) mmHg for nitroglycerin alone compared to 22.63 (- 25.06, - 20.21)/12.94 (- 14.38, - 11.49) mmHg when co-administered with sacubitril/valsartan. Co-administration of sacubitril/valsartan and nitroglycerin did not result in further plasma cGMP increase compared to sacubitril/valsartan alone. The co-administration of nitroglycerin and sacubitril/valsartan was safe and well tolerated and did not impact the pharmacokinetics of sacubitril/valsartan. The results from this study demonstrate no pharmacodynamic drug interaction between nitroglycerin and sacubitril/valsartan in healthy subjects, suggesting that no change of dose selection and escalation recommendations or clinical monitoring during nitroglycerin administration is required.

Effect of Preoperative Pregabalin on Induced Hypotension and Postoperative Analgesia with Functional Endoscopic Sinus Surgery

Background: Our target was to estimate the effect of pregabalin as premedication on deliberate hypotension and quality of the surgical site during functional endoscopic surgery for nasal sinuses (FESS) and its postoperative analgesic effect.Materials and methods: Eighty patients ASA I-II prepared for FESS were included in this randomized research. The study encompassed 2 groups [control group (C) and pregabalin group (P)]. Patients were given either placebo capsule [group (C)] or pregabalin capsule 150 mg [group (P)] 1 h preoperatively. During surgery mean arterial blood pressure (MAP) was maintained between 55-60 mmHg by intravenous infusion of nitroglycerin (NTG) at a rate of 0.5-10 μg/kg/min. We recorded quality of surgical site [using average category scale (ACS)], the overall dose of NTG used, postoperative pain, the overall dose of morphine used postoperatively, and number of patients requesting analgesia.Results: Pregabalin group (P) showed better ACS, lower overall dose of NTG used, less postoperative pain, lower overall dose of morphine, and less number of patients requesting analgesia than control group (C).Conclusion: Preoperative oral pregabalin improved the quality of the surgical site during FESS, and decreased the required dose of intraoperative hypotensive agent and postoperative morphine with better postoperative analgesia.

Regional to the Rescue! Axillary Brachial Plexus Nerve Block Facilitates Removal of Entrapped Transradial Catheter Placed for Cardiac Catheterization

Our objective was to describe the first reported use of an axillary brachial plexus block to treat the entrapment of a transradial artery catheter due to vasospasm. A 42-year-old man undergoing transradial arterial cardiac catheterization suffered arterial vasospasm causing the catheter to become entrapped and refractory to conservative (warm compresses) and standard pharmacologic interventions (intracatheter verapamil, intravenous infusions of nitroglycerin and nicardipine, and subcutaneous lidocaine and topical nitroglycerin). Anesthesia was consulted, and attempts at catheter removal under monitored anesthesia and general anesthesia failed. Finally, in order to avoid surgical intervention, an ultrasound-guided axillary brachial plexus block with mepivacaine was performed, resulting in easy removal of the catheter. Axillary brachial plexus nerve blocks are an effective, efficient, and safe intervention with a wide range of indications. This case report demonstrates that an axillary nerve block can be used to treat the entrapment of a transradial artery catheter due to vasospasm.

Intravenous Infusion of Nitroglycerine Leads to Increased Permeability on Dynamic Contrast-Enhanced MR Imaging in Pig Brains.

It has been suggested that off-label use of transdermal nitroglycerine patches to prevent frostbite may lead to severe acute mountain sickness and ataxia. The aim of this study was to investigate the effect of nitroglycerine on brain vascular permeability by using dynamic contrast-enhanced MR imaging in a swine model. Eight Danish Landrace-Yorkshire-Danish Landrace pigs of approximately 20-25 kg were scanned with a dynamic contrast-enhanced MR perfusion protocol with and without nitroglycerine intravenous infusion. Compartmental analysis was performed on the basis of the Tofts model, and voxel-based quantitative values of the volume transfer constants from the vascular to the extracellular space were determined. The scan with nitroglycerine infusion resulted in significantly higher volume transfer constant values than values derived from the first scan without nitroglycerine infusion. Increased volume transfer constant values were observed in 6 of 8 animals. Infusion of nitroglycerine increases the vascular permeability of the swine brain on the basis of the transfer constant estimated from dynamic contrast-enhanced MR imaging.

Mechanisms of glyceryl trinitrate provoked mast cell degranulation.

Migraine patients develop attacks several hours after intravenous infusion of glyceryl trinitrate. Due to the short half-life of nitric oxide, this delayed migraine cannot be caused by a direct action of nitric oxide derived from glyceryl trinitrate. The involvement of meningeal inflammation and dural mast cell degranulation is supported by the effectiveness of prednisolone on glyceryl trinitrate-induced delayed headache. Using a newly developed rat model mimicking the human glyceryl trinitrate headache model, we have investigated the occurrence of dural mast cell degranulation after a clinically relevant dose of glyceryl trinitrate. A 6-fold increase in degranulation was observed starting at 2 hours after glyceryl trinitrate infusion. Interestingly, pre-treatment with the effective anti-migraine substances L-nitro-arginine methyl ester and sumatriptan prevented glyceryl trinitrate-induced mast cell degranulation whereas the calcitonin gene-related peptide-receptor antagonist olcegepant and the substance P receptor antagonist L-733,060 did not affect mast cell degranulation. However, topical application of two different nitric oxide donors did not cause mast cell degranulation ex vivo. Direct application of an exogenous nitric oxide donor on dural mast cells does not cause mast cell degranulation ex vivo. Invivo application of the nitric oxide donor glyceryl trinitrate leads to a prominent level of degranulation via a yet unknown mechanism. This effect can be completely blocked by inhibition of the endogenous nitric oxide production and by 5-HT1B/1D receptor agonists but is unaffected by calcitonin gene-related peptide and substance P receptor antagonists.

“Requiring Intravenous Nitroglycerin” Should be considered a High Risk Feature in Patients with Non-ST Elevation Myocardial Infarction and Unstable Angina

Introduction: Early risk stratification of patients with unstable angina (UA) and non-ST elevation myocardial infarction (NSTEMI) is crucial to identify those at high risk for further cardiac events as they may benefit from an early invasive strategy of coronary angiography and revascularization. The TIMI score, a widely used predictive model to guide management strategy in UA and NSTEMI may not accurately stratify risk. Case description: A 63-year-old man, who is an active smoker with past medical history of hypertension and dyslipidemia, presented with severe sub-sternal, crushing chest pain, which began four hours prior to presentation. His EKG revealed sinus tachycardia, without ST segment deviations or Q waves. He received aspirin, three doses of sublingual nitroglycerin and metoprolol, but continued to have chest pain, thus he was commenced on intravenous nitroglycerin infusion. His chest pain went away after two hours on nitroglycerin infusion. His initial serum troponin I was 0.31 ng/mL and 3.60 ng/mL four hours after presentation. He was admitted for NSTEMI and started on clopidogrel, atorvastatin and intravenous heparin. Echocardiogram revealed inferio-septal wall a kinesis and severely reduced left ventricular systolic function. His troponin I continued to rise, peaking at 37.4 ng/mL. He was started on eptifibatide and was referred for coronary angiography and percutaneous coronary intervention, with finding of fifty percent proximal and distal left anterior descending artery (LAD) lesions. Discussion: With a TIMI score of 2, our patient was classified as low risk at presentation. The need for intravenous nitroglycerin infusion for continuing chest pain in the management of UA or NSTEMI may suggest a greater degree of myocardial ischemia and a higher risk for adverse cardiovascular outcomes. This case demonstrates that UA and NSTEMI patients requiring intravenous nitroglycerin initially planned for conservative therapeutic approach need continuous risk stratification which may dictate a change to the invasive management strategy.

Angiotensin II receptor blocker telmisartan attenuates aortic stiffening and remodelling in STZ-diabetic rats.

BackgroundPrevention or attenuation of diabetic vascular complications includes anti-hypertensive treatment with renin-angiotensin system inhibitors on account of their protective effects beyond blood pressure reduction. The present study aimed to investigate the effects of telmisartan, an angiotensin II type 1 receptor blocker (ARB), on blood pressure, aortic stiffening, and aortic remodelling in experimental type 1 diabetes in rats.MethodsDiabetes was induced by streptozotocin (STZ) (65 mg/kg) in male Wistar rats. One diabetic group was treated for 10 weeks with telmisartan (10 mg/kg/day p/o). Pressure-independent aortic pulse wave velocity (PWV) was measured under anaesthesia after intravenous infusion of phenylephrine and nitroglycerine. Aortic wall samples were collected for histomorphometrical analysis.ResultsUntreated diabetes imposed differential effects on aortic stiffening, as demonstrated by increased isobaric PWV over a range of high blood pressures, but not at lower blood pressures. This was associated with loss and disruption of elastin fibres and an increase in collagen fibres in the aortic media. Treatment with telmisartan decreased resting blood pressure, reduced aortic stiffness, and partially prevented the degradation of elastin network within the aortic wall.ConclusionsTelmisartan improved the structural and functional indices of aortic stiffening induced by untreated STZ-diabetes, demonstrating the importance of ARBs in the therapeutic approach to diabetic vascular complications.

The effects of nitroglycerin, norepinephrine and aminophylline on intrapulmonary arteriovenous anastomoses in healthy humans at rest

We have investigated the effects of the intravenous infusion of nitroglycerin (NTG), norepinephrine (NE) and aminophylline (AMP) on the opening and recruitment of intrapulmonary arteriovenous anastomoses (IPAVA) in healthy humans at rest. In ten volunteers saline contrast echocardiography was performed during administration of two doses of the NTG (3μgkg−1min−1 and 6μgkg−1min−1) and NE (0.1μgkg−1min−1 and 0.25μgkg−1min−1) as well as 30min following the administration of AMP at rate of 6mgkg−1. Echocardiography was used to assign bubble scores (0–5) based on the number and spatial distribution of bubbles in the left ventricle. Doppler ultrasound was used to estimate pulmonary artery systolic pressure. Using a Finometer the following hemodynamic parameters were assessed: heart rate, stroke volume, cardiac output, total peripheral resistance as well as systolic, diastolic and mean arterial pressure. The most important finding from the current study was that nitroglycerin, norepinephrine and aminophylline in the applied doses were not found to promote IPAVA opening in healthy humans at rest.