Transient Hypertension Research Articles

Scleral Buckle Removal: Indications, Timing, Complications, and Long-Term Outcomes

To report indications, timing, complications, and outcomes of scleral buckle (SB) removal surgery. Retrospective observational case series. Eyes that underwent SB removal between 2010 and 2016 with greater than 1 year of follow-up were included. Main outcome measures were post-SB removal complications and best-corrected visual acuity (BCVA). Fifty eyes that underwent SB removal met the inclusion criteria. Indications include exposed SB (54%), infection (26%), diplopia (16%), and recurrent retinal detachment (4%). Mean and median intervals between SB placement and removal were 65 months and 30 months. Complications include recurrent retinal detachment (12%), transient ocular hypertension (6%), and persistent diplopia (4%). There was no significant change in mean BCVA after SB removal (P = .979). Exposed SB, infection, and diplopia are the most common indications for SB removal. The single-surgery success rate is high and the risk for complications is relatively low. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:138-144.].

Cerebrovascular damage after midlife transient hypertension in non-transgenic and Alzheimer’s disease rats

Hypertension, including transient events, is a major risk factor for developing late-onset dementia and Alzheimer’s disease (AD). Anti-hypertensive drugs facilitate restoration of normotension without amelioration of increased dementia risk suggesting that transient hypertensive insults cause irreversible damage. This study characterized the contribution of transient hypertension to sustained brain damage as a function of normal aging and AD. To model transient hypertension, we treated F344TgAD and non-transgenic littermate rats with L-NG-Nitroarginine methyl ester (L-NAME) for one month, ceased treatment and allowed for a month of normotensive recovery. We then examined the changes in the structure and function of the cerebrovasculature, integrity of white matter, and progression of AD pathology. As independent factors, both transient hypertension and AD compromised structural and functional integrity across the vascular bed, while combined effects of hypertension and AD yielded the largest deficits. Combined effects of transient hypertension and AD genotype resulted in loss of cortical myelin particularly in the cingulate cortex which is crucial for cognitive function. Increased cerebral amyloid angiopathy, a prominent pathology of AD, was detected after transient hypertension as were up- and down-regulation of proteins associated with cerebrovascular remodeling – osteopontin, ROCK1 and ROCK2, in F344TgAD rats even 30 days after restoration of normotension. In conclusion, transient hypertension caused permanent cerebrovasculature and brain parenchymal damage in both normal aging and AD. Our results corroborate human studies that have found close correlation between transient hypertension in midlife and white matter lesions later in life outlining vascular pathologies as pathological links to increased risk of dementia.

Percutaneous cryoablation of adrenal metastases: technical feasibility and safety.

To assess the technical feasibility and outcomes of adrenal metastases cryoablation. This is an IRB approved retrospective review of adrenal metastases cryoablation between April 2003 and October 2018. Forty percutaneous cryoablation procedures were performed on 40 adrenal metastases in 34 patients. Histology, tumor size, ablation zone size, major vessel proximity, local recurrences, complications, and anesthesia-managed hypertension monitoring was collected. Complications were graded according to the Common Terminology of Complications and Adverse Events (CTCAE). Mean tumor and ablation size was 3.2cm and 5.2cm, respectively. Local recurrence rate was 10.0% (N = 4/40) for a mean follow-up time of 1.8years. Recurrences for tumors > 3cm (21.0%, N = 4/19) was greater than for tumors ≤ 3cm (0.0%, N = 0/21) (p = 0.027). Proximity of major vasculature (i.e., IVC & aorta) did not statistically effect recurrence rates (p = 0.52), however, those that recurred near vasculature were > 4cm. Major complication (≥ grade 3) rate was 5.0% (N = 2/40), with one major complication attributable to the procedure. Immediate escalation of blood pressure during the passive stick phase (between freeze cycles) or post procedure thaw phase was greater in patients with residual adrenal tissue (N = 21/38) versus masses replacing the entire adrenal gland (N = 17/38), (p = 0.0020). Lower blood pressure elevation was noted in patients with residual adrenal tissue who were pre-treated with alpha blockade (p = 0.015). CT-guided percutaneous cryoablation is a safe, effective and low morbidity alternative for patients with adrenal metastases. Transient hypertension is related only to residual viable adrenal tissue but can be safely managed and prophylactically treated.

Hypertension preserves the magnitude of microvascular flow-mediated dilation following transient elevation in intraluminal pressure.

ObjectiveThe objective of this study was to measure flow‐mediated dilation (FMD) prior to and following transient increases in intraluminal pressure (IILP) in resistance arterioles isolated from subjects with and without coronary artery disease (CAD) (CAD and non‐CAD) and non‐CAD subjects with hypertension.MethodsArterioles were isolated from discarded surgical tissues (adipose and atrial) from patients without coronary artery disease (non‐CAD; ≤1 risk factor, excluding hypertension), with CAD, and non‐CAD patients with hypertension (hypertension as the only risk factor). To simulate transient hypertension, increased IILP was generated (150 mmHg, 30 min) by gravity. Arterioles were constricted with endothelin‐1, followed by FMD and endothelial‐independent dilation prior to and following exposure to IILP.ResultsIILP reduced FMD in non‐CAD and CAD arterioles relative to pre‐IILP (p <.05 at 100 cmH2O). In contrast, arterioles from non‐CAD hypertensive subjects exhibited no reduction in maximal FMD following IILP (p = .84 at 100 cmH2O). FMD was reduced by L‐NAME prior to IILP in non‐CAD hypertensive patients (p < .05 at 100 cmH2O); however, following IILP, FMD was inhibited by peg‐cat (p < .05 at 100 cmH2O), indicating a switch from NO to H2O2 as the mechanism of dilation.ConclusionsAcute exposure (30 min) to IILP (150 mmHg) attenuates the magnitude of FMD in non‐CAD and CAD resistance arterioles. The presence of clinically diagnosed hypertension in non‐CAD resistance arterioles preserves the magnitude of FMD following IILP as a result of a compensatory switch from NO to H2O2 as the mechanism of dilation.

Role of Cardiac A2A Receptors Under Normal and Pathophysiological Conditions.

This review presents an overview of cardiac A2A-adenosine receptors The localization of A2A-AR in the various cell types that encompass the heart and the role they play in force regulation in various mammalian species are depicted. The putative signal transduction systems of A2A-AR in cells in the living heart, as well as the known interactions of A2A-AR with membrane-bound receptors, will be addressed. The possible role that the receptors play in some relevant cardiac pathologies, such as persistent or transient ischemia, hypoxia, sepsis, hypertension, cardiac hypertrophy, and arrhythmias, will be reviewed. Moreover, the cardiac utility of A2A-AR as therapeutic targets for agonistic and antagonistic drugs will be discussed. Gaps in our knowledge about the cardiac function of A2A-AR and future research needs will be identified and formulated.

Risk factors for postpartum readmission for preeclampsia or hypertension before delivery discharge among low-risk women: a case-control study

Postpartum hypertension or preeclampsia is one of the most frequent reasons for readmission after delivery discharge, and risk factors for readmission remain poorly characterized. This study aimed to determine risk factors of postpartum readmission for hypertension or preeclampsia among low-risk women before delivery discharge. We conducted a nested case-control study from 2012 to 2015 at a tertiary care medical center. Cases were identified using diagnostic codes for postpartum transient hypertension, mild preeclampsia, severe preeclampsia, eclampsia, superimposed preeclampsia, and unspecified hypertension and readmission within 6 weeks of delivery. Controls not readmitted for hypertension or preeclampsia were time matched within 4 weeks of the delivery date to each case. We fit multivariable logistic regression models to identify independent risk factors for postpartum readmission for hypertension or preeclampsia and then calculated a receiver operating characteristic curve of the final model to assess model discrimination. Within the source cohort resulting in 58 cases and 232 matched controls, the rate of postpartum readmission for preeclampsia or hypertension was 0.4% (n=58 of 14,503). The median time to readmission was 6 days (range, 2-15 days), and 40% of cases had an outpatient postpartum visit before readmission. In multivariable analysis, non-Hispanic black race (adjusted odds ratio, 2.14; 95% confidence interval, 0.99-4.59), gestational hypertension (adjusted odds ratio, 2.70; 95% confidence interval, 1.12-6.54), preeclampsia during delivery admission (adjusted odds ratio, 3.12; 95% confidence interval, 1.29-7.50), and maximum postpartum systolic blood pressure during delivery admission (adjusted odds ratio, 1.05; 95% confidence interval, 1.03-1.08) were risk factors for readmission. This model had a good discriminative ability to predict women who would require readmission for preeclampsia or hypertension (area under the curve, 0.83; 95% confidence interval, 0.74-0.89). Using these 4 factors to illustrate this model, the predicted risk of readmission ranged from <1% in the lowest risk scenario (eg, postpartum systolic blood pressure of 120 mm Hg + no hypertensive disorders of pregnancy + white race) to 26% in the highest risk scenario (eg, postpartum systolic blood pressure of 160 mm Hg + preeclampsia + black race). Risk factors of postpartum readmission for hypertension or preeclampsia can be identified at the time of delivery discharge among low-risk women, regardless of an antenatal hypertensive disorder. A next step could be using these risk factors to develop a predictive model to guide postpartum care.

Surgical Technique for Pars Plana Ahmed Glaucoma Valve Implantation in Advanced Glaucoma: The Upside-Down Technique.

Ahmed glaucoma valve (AGV) implantation using the upside-down technique resulted in an aqueous humor outflow pathway, occurring primarily on the scleral side and secondarily on the conjunctival side, and was effective in treating refractory glaucoma. To describe the AGV surgical technique, which results in changes in the primary aqueous humor outflow pathway to the scleral side (upside-down technique), and to evaluate the clinical effects and distribution of bleb fluid after surgery in patients with refractory glaucoma. In this retrospective study, the upside-down technique was used for pars plana AGV implantation in 10 eyes of 10 patients with refractory glaucoma. Surgical success was defined by complications, intraocular pressure (IOP), the glaucoma medication score, and bleb fluid distribution determined by magnetic resonance imaging. Postoperatively, there were significant reductions in the IOP and medication score at 23 and 27 months, respectively (P<0.05). Although a transient hypertensive phase was observed in 7 patients, it was controlled without ocular massage and additional surgery. A patient who had suprachoroidal hemorrhage during surgery lost light perception 7 months after the surgery, and another patient developed hypotony at 3 and 4 months after surgery, which spontaneously improved during subsequent examinations. Magnetic resonance imaging showed that the double bleb layer adjacent to the endplate tended to have more bleb fluid on the conjunctival side than on the scleral side facing the outlet (n=8; 1 to 29 mo after surgery). Pars plana AGV implantation using the upside-down technique was a relatively effective alternative to manage inadequate IOP control in patients with refractory glaucoma.

Safety, Tolerability, and Real-World Effectiveness of Intravenous Ketamine in Older Adults With Treatment-Resistant Depression: A Case Series

To evaluate the safety, tolerability, and effectiveness of repeated doses of intravenous (IV) ketamine in older adults (i.e., ≥60 years of age) with treatment-resistant depression. In this case series, fifty-three older adults (Mage = 67, SD = 6; 57% female [n = 30]) received 4 IV ketamine infusions, administered over 1-2 weeks. Effectiveness of IV ketamine was measured using the Quick Inventory for Depressive Symptomatology-Self Report 16 (QIDS-SR16) approximately 2 days after infusions 1-3, and 1-2 weeks after infusion 4. Safety was measured as hemodynamic changes before, during, immediately after, and 20 minutes after each infusion. Tolerability was assessed via systematic reporting of treatment-emergent adverse events during and after each infusion, in addition to symptoms of dissociation measured using the Clinician Administered Dissociative States Scale. Partial response (25%-50% symptomatic improvement from baseline), response (≥50% symptomatic improvement from baseline), clinically significant improvements (≥25% symptomatic improvement from baseline), and remission rates (QIDS-SR16 ≤5) were also calculated. Participants reported significant decreases in depressive symptoms (i.e., as measured by the QIDS-SR16) with repeated ketamine infusions (F(4, 92) = 7.412, p <0.001). The mean QIDS-SR16 score was 17.12 (SD = 5.33) at baseline and decreased to 12.52 (SD = 5.79) following 4 infusions. After 4 infusions, 31% (n = 8) of participants partially responded to IV ketamine, 27% (n = 7) responded, 58% (n = 15) experienced clinically significant improvements, and 10% (n = 3) met remission criteria. Thirty-six participants (69%) experienced treatment-emergent hypertension during at least 1 infusion, and 10 (19%) required intervention with an antihypertensive. Drowsiness was the most commonly reported adverse event (50% of infusions; n = 73). Ketamine was associated with transient treatment-emergent hypertension. Response and remission rates were comparable to those reported in general adult samples. Findings are limited by the open-label, chart review nature of this study.

Errors and Consequences of Inaccurate Estimation of Mean Blood Flow Velocity in Cerebral Arteries.

Many transcranial Doppler ultrasonography devices estimate the mean flow velocity (FVm) by using the traditional formula (FVsystolic + 2×FVdiastolic)/3 instead of a more accurate formula calculating it as the time integral of the current flow velocities divided by the integration period. We retrospectively analyzed flow velocity and intracranial pressure signals containing plateau waves (transient intracranial hypertension), which were collected from 14 patients with a traumatic brain injury. The differences in FVm and its derivative pulsatility index (PI) calculated with the two different methods were determined. We found that during plateau waves, when the intracranial pressure (ICP) rose, the error in FVm and PI increased significantly from the baseline to the plateau (from 4.6±2.4 to 9.8±4.9cm/s, P<0.05). Similarly, the error in PI also increased during plateau waves (from 0.11±0.07 to 0.44±0.24, P<0.005). These effects were most likely due to changes in the pulse waveform during increased ICP, which alter the relationship between systolic, diastolic, and mean flow velocities. If a change in the mean ICP is expected, then calculation of FVm with the traditional formula is not recommended.

Sutureless Scleral Fixated IOL: The "Catcher Pole" Technique.

PurposeTo describe a new surgical technique for sutureless intrascleral intraocular lens (IOL) fixation with an adapted retinal scraper used as an instrument “the Catcher Pole” to retrieve the IOL haptic through a scleral tunnel.SettingPublic Eye Hospital, Roma, Italy.DesignRetrospective case series.MethodsTwenty-one eyes from 19 patients who underwent sutureless intrascleral IOL fixation were studied. A standard three-piece posterior chamber IOL (PCIOL) was implanted in aphakia or rescued and fixated in cases of dislocated PCIOL. A 23 to 25 G retinal loop scraper (the “Catcher Pole“) was inserted through a 1.5 mm long tunneled sclerotomy performed on the horizontal meridian, to capture, hold and externalize the tip of the haptic of the IOL. A flange created with an handheld cautery on the externalized haptic tip prevents IOL slippage. The best-corrected visual acuity (BCVA), central corneal pachymetry (CCP), IOL tilt and complications were assessed.ResultsIn twenty-one eyes of 19 patients, the mean preoperative BCVA was 0.61 logMAR units ±0.05 SD, and the mean postoperative BCVA improved significantly to 0.18 logMAR units at three months ±0.05 SD (P=0.002). The mean preoperative CCP was 610 µ ±17 SD and the mean postoperative CCP 623 µ ±16 SD, (P=0.73). In the subgroup that underwent IOL tilt evaluation, mean IOL tilt was 3.19±2.01. The postoperative complications included iris capture of the IOL in one eye (4,7%) and transient ocular hypertension in two eyes (9,4%).ConclusionsThe “Catcher Pole” sutureless intrascleral IOL fixation technique is easy to perform with reduced anterior chamber manipulations and achieves both anatomical and optical stability.

Combination treatment of copanlisib and gemcitabine in relapsed/refractory PTCL (COSMOS): an open-label phase I/II trial

Current treatment options for peripheral T-cell lymphomas (PTCLs) in the relapsed/refractory setting are limited and demonstrate modest response rates with rare achievement of complete response (CR). This phase I/II study (NCT03052933) investigated the safety and efficacy of copanlisib, a phosphatidylinositol 3-kinase-α/-δ inhibitor, in combination with gemcitabine in 28 patients with relapsed/refractory PTCL. Patients received escalating doses of intravenous copanlisib on days 1, 8, and 15, administered concomitantly with fixed-dose gemcitabine (1000 mg/m2 on days 1 and 8) in 28-day cycles. Dose-limiting toxicity was not observed in the dose-escalation phase and 60 mg copanlisib was selected for phase II evaluation. Twenty-five patients were enrolled in phase II of the study. Frequent grade ≥3 adverse events (AEs) included transient hyperglycemia (57%), neutropenia (45%), thrombocytopenia, (37%), and transient hypertension (19%). However, AEs were manageable, and none were fatal. The overall response rate was 72% with a CR rate of 32%. Median duration of response was 8.2 months, progression-free survival was 6.9 months, and median overall survival was not reached. Combination treatment produced a greater CR rate in patients with angioimmunoblastic T-cell lymphoma than those with PTCL-not otherwise specified (55.6% versus 15.4%, respectively, P= 0.074) and progression-free survival was significantly longer (13.0 versus 5.1 months, respectively, P= 0.024). In an exploratory gene mutation analysis of 24 tumor samples, TSC2 mutation was present in 25% of patients and occurred exclusively in responders. The combination of copanlisib and gemcitabine is a safe and effective treatment option in relapsed/refractory PTCLs and represents an important new option for therapy in this rare group of patients.

Is robot-assisted retroperitoneal adrenalectomy safe? An investigation of perioperative hypertensive crisis among hypertensive and normotensive patients.

Objective: We examined the incidence of perioperative hypertensive crisis in robot-assisted retroperitoneal laparoscopic adrenalectomy. A consecutive series of 120 patients with adrenal tumours undergoing robot-assisted retroperitoneal laparoscopic adrenalectomy were included. Patients were divided into two groups: group A (hypertension group, 58 cases, mean age 43.59 years) and group B (normotension group, 62 cases, mean age 48.01 years). General anaesthesia was applied using endotracheal intubation and haemodynamic changes were closely monitored. A total of nine (7.5%) hypertensive crisis cases were observed. After intravenous infusion of sodium nitroprusside, seven cases of them were quickly controlled and two cases experienced transient severe hypertension. The incidence of hypertensive crisis was 13.7% and 1.6% in groups A and B, respectively (p<0.05). These findings highlight the importance of strengthening the monitoring of anaesthesia and taking various measures to effectively control the blood pressure in robot-assisted retroperitoneal laparoscopic adrenalectomy, especially among hypertensive patients.

Transient Pulmonary Artery Hypertension in Holstein Neonate Calves.

Simple SummaryAt birth, calves are challenged to maintain their vital functions that were previously supported by the placenta of cows. Failures in the neonatal adaptation process can occur during this and can cause the death of neonates. The present study aimed at the invasive hemodynamic evaluation of calves during the first 30 days of life to elucidate the changes in calves during this stage of life. In conclusion, the results of this research show a transient pulmonary arterial hypertension during the process of adapting to extrauterine life.The neonatal period is a challenging phase for calves, and during this phase constant adaptations are required. The aim of the present study was to evaluate the invasive hemodynamics with the Swan-Ganz catheter in neonate calves to understand adaptive changes during the first 30 days of life. A prospective and observational study was conducted with 10 Holstein calves. Assessments of the right atrial pressure (RAP), right ventricular pressure (RVP), pulmonary artery pressure (PAP), pulmonary capillary pressure (PW), cardiac output (CO), heart rate (HR), pulmonary vascular resistance (PVR), and blood gas levels were performed. The analyses of PAP, PVR, PW, HR, sO2, and arterial blood gases differed (p < 0.05) between the evaluated periods. Our results indicated transient pulmonary artery hypertension during the process of extrauterine adaptation during the first 30 days of life. This hypertension must be considered as physiological and consequent to the neonatal adaptation process.

Centruroides margaritatus scorpion complete venom exerts cardiovascular effects through alpha-1 adrenergic receptors

Centruroides margaritatus scorpion stings are common in Colombia. However, the cardiovascular toxicity of the venom has not been clarified. Aim: To study the effect and mechanisms of action of the complete venom of C. margaritatus (CmV) on the murine cardiovascular system. Methods: We evaluated the in vivo effect of CmV LD50 on the mean arterial pressure (MABP), heart rate, and surface electrocardiogram in male adult normotensive Wistar rats. Ex vivo, we evaluated the vascular reactivity of rat aortic rings to increasing concentrations (1 to 60 μg/mL) of CmV using the blockers L-NAME, indomethacin, seratrodast, and prazosin. Results: In the first hour of poisoning, CmV increased the MABP. In the second hour after poisoning, the heart rate decreased as the normalized PR interval and QT corrected increased. After that, cardiovascular shock was demonstrated by a drastic fall in the MABP and signs of cardiac conduction system block. In aortic rings, CmV caused a direct vasoconstrictor effect mediated by alpha-1 adrenergic receptors and counteracted by nitric oxide. Conclusion: The direct vascular and probably the cardiac alpha-1 effects likely explain the transient hypertension and the maintenance of cardiac function, while interval lengthening may be due to K+ channel blockage. Afterwards, the effects of both the alpha-1 pathway and the K+ channel pathway converged, resulting in fatal cardiovascular shock. This knowledge could aid in understanding the dynamics of the effects of the venom and in designing treatments to address its cardiovascular effects.

Effects of antenatal dexamethasone and hyperglycemia on cardiovascular adaptation to asphyxia in preterm fetal sheep.

Antenatal glucocorticoids improve outcomes among premature infants but are associated with hyperglycemia, which can exacerbate hypoxic-ischemic injury. It is still unclear how antenatal glucocorticoids or hyperglycemia modulate fetal cardiovascular adaptations to severe asphyxia. In this study, preterm fetal sheep received either saline or 12 mg im maternal dexamethasone, followed 4 h later by complete umbilical cord occlusion (UCO) for 25 min. An additional cohort of fetuses received titrated glucose infusions followed 4 h later by UCO to control for the possibility that hyperglycemia contributed to the cardiovascular effects of dexamethasone. Fetuses were studied for 7 days after UCO. Maternal dexamethasone was associated with fetal hyperglycemia (P < 0.001), increased arterial pressure (P < 0.001), and reduced femoral (P < 0.005) and carotid (P < 0.05) vascular conductance before UCO. UCO was associated with bradycardia, femoral vasoconstriction, and transient hypertension. For the first 5 min of UCO, fetal blood pressure in the dexamethasone-asphyxia group was greater than saline-asphyxia (P < 0.001). However, the relative increase in arterial pressure was not different from saline-asphyxia. Fetal heart rate and femoral vascular conductance fell to similar nadirs in both saline and dexamethasone-asphyxia groups. Dexamethasone did not affect the progressive decline in femoral vascular tone or arterial pressure during continuing UCO. By contrast, there were no effects of glucose infusions on the response to UCO. In summary, maternal dexamethasone but not fetal hyperglycemia increased fetal arterial pressure before and for the first 5 min of prolonged UCO but did not augment the cardiovascular adaptations to acute asphyxia.

Xylazine, a Veterinary Tranquilizer, Detected in 42 Accidental Fentanyl Intoxication Deaths.

Xylazine is an emerging adulterant with fentanyl in fatal drug intoxications, which has public health, safety, and criminal investigative implications. Xylazine is a nonnarcotic sedative used for analgesia and muscle relaxation exclusively in veterinary medicine. Its chemical structure is similar to clonidine and acts as a central α-2 agonist which may cause bradycardia and transient hypertension followed by hypotension. We report the detection of xylazine in 42 deaths in Connecticut from March to August 2019. Xylazine combined with an opioid or stimulant may affect the toxicity of these drugs. Detection of xylazine may help the forensic pathologist distinguish illicit from prescribed fentanyl, and law enforcement agents track the illicit drugs to a specific drug supplier. Because of its lack of response to naloxone, emergency medicine physicians need to be aware of its potential presence as it may affect therapy.

The Clinical Characteristics of Patients with Embolic Strokes among Indonesian Subjects

Stroke accounts for 10% of the world's deaths and causes severe long-term disabilities. Twenty-six million people world wide experience a stroke each year. Two-thirds represents cerebral ischemia. Age, a history of stroke or transient ischemic attack, hypertension, diabetes and heart failure characterize a stroke. Early detection with a proper treatment could improve clinical outcomes in such cases.

Transient hypertension as a complication of circular external fixator- Ilizarov frame

Transient hypertension as a complication of circular external fixator- Ilizarov frame

Erythropoietin plus iron versus control treatment including placebo or iron for preoperative anaemic adults undergoing non-cardiac surgery.

Erythropoietin plus iron versus control treatment including placebo or iron for preoperative anaemic adults undergoing non-cardiac surgery.

Prehospital Efficacy and Adverse Events Associated with Bolus Dose Epinephrine in Hypotensive Patients During Ground-Based EMS Transport.

The utility and efficacy of bolus dose vasopressors in hemodynamically unstable patients is well-established in the fields of general anesthesia and obstetrics. However, in the prehospital setting, minimal evidence for bolus dose vasopressor use exists and is primarily limited to critical care transport use. Hypotensive episodes, whether traumatic, peri-intubation-related, or septic, increase patient mortality. The purpose of this study is to assess the efficacy and adverse events associated with prehospital bolus dose epinephrine use in non-cardiac arrest, hypotensive patients treated by a single, high-volume, ground-based Emergency Medical Services (EMS) agency. This is a retrospective, observational study of all non-cardiac arrest EMS patients treated for hypotension using bolus dose epinephrine from September 12, 2018 through September 12, 2019. Inclusion criteria for treatment with bolus dose epinephrine required a systolic blood pressure (SBP) measurement <90mmHg. A dose of 20mcg every two minutes, as needed, was allowed per protocol. The primary data source was the EMS electronic medical record. Forty-two patients were treated under the protocol with a median (IQR) initial SBP immediately prior to treatment of 78mmHg (65-86) and a median (IQR) initial mean arterial pressure (MAP) of 58mmHg (50-66). The post-bolus SBP and MAP increased to 93mmHg (75-111) and 69mmHg (59-83), respectively. The two most common patient presentations requiring protocol use were altered mental status (55%) and respiratory failure (31%). Over one-half of the patients treated required both advanced airway management (62%) and multiple bolus doses of vasopressor support (55%). A single episode of transient severe hypertension (SBP>180mmHg) occurred, but there were no episodes of unstable tachyarrhythmia or cardiac arrest while en route or upon arrival to the receiving hospitals. These preliminary data suggest that the administration of bolus dose epinephrine may be effective at rapidly augmenting hypotension in the prehospital setting with a minimal incidence of adverse events. Paramedic use of bolus dose epinephrine successfully increased SBP and MAP without clinically significant side effects. Prospective studies with larger sample sizes are needed to further investigate the effects of prehospital bolus dose epinephrine on patient morbidity and mortality.