Maintain Mean Arterial Blood Pressure Research Articles

Effect of terlipressin on systemic and hepatic hemodynamics in patients undergoing liver transplantation

ABSTRACT Background and Aims Liver transplantation is associated with hemodynamic instability. Systemic and Splanchnic circulations interact closely. Portal hypertension is linked to vasodilatory molecules resulting in arterial vasodilatation. Terlipressin, is a synthetic vasopressin analogue causes selective vasoconstriction of splanchnic arteriols, thus decreasing splanchnic blood flow and shifting blood from the splanchnic to the systemic circulation resulting in enhanced systemic hemodynamics. This study aimed to assess the impact of intraoperative terlipressin on systemic and hepatic hemodynamics in recipients of living donor liver transplantation (LDLT). Methods The present longitudinal observational study was carried out at Ain Shams Center for Organ Transplant on 30 cases suffering from portal hypertension and chronic liver disease undergoing LDLT. Subjects were equally categorized into two groups: Group 1(control): patients did not receive intraoperative terlipressin, Group 2 (terlipressin): patients received terlipressin (1 mg intravenously over 10 min) just after exposure of the portal vein to maintain mean arterial blood pressure over 65 mmHg. Results Systolic and diastolic blood pressure were better preserved in the terlipressin group, with reduced norepinephrine requirements as well as a substantial decline in the heart rate during the anhepatic and reperfusion phases (P < 0.05). Terlipressin significantly decreases portal venous pressure with (P = 0.03) and portal vein flow (P < 0.001) without altering the hepatic artery resistivity index (HARI) (P = 0.219). Conclusion Intraoperative terlipressin during liver transplantation surgery was associated with improved systemic hemodynamics despite decreased portal venous pressure and blood flow, without affecting HARI.

Comparison of clinical outcomes between active and permissive blood pressure management in extremely preterm infants.

There remains uncertainty about the definition of normal blood pressure (BP), and when to initiate treatment for hypotension for extremely preterm infants. To determine the short-term outcomes of extremely preterm infants managed by active compared with permissive BP support regimens during the first 72 hours of life. This is a retrospective medical records review of 23 +0-28 +6 weeks' gestational age (GA) infants admitted to neonatal units (NNU) with active BP support (aimed to maintain mean arterial BP (MABP) >30 mmHg irrespective of the GA) and permissive BP support (used medication only when babies developed signs of hypotension) regimens. Babies admitted after 12 hours of age, or whose BP data were not available were excluded. There were 764 infants admitted to the participating hospitals; 671 (88%) were included in the analysis (263 active BP support and 408 permissive BP support). The mean gestational age, birth weight, admission temperature, clinical risk index for babies (CRIB) score and first haemoglobin of infants were comparable between the groups. Active BP support group infants had consistently higher MABP and systolic BP throughout the first 72 hours of life (p<0.01). In the active group compared to the permissive group 56 (21.3%) vs 104 (25.5%) babies died, and 21 (8%) vs 51 (12.5%) developed >grade 2 intra ventricular haemorrhage (IVH). Death before discharge (adjusted OR 1.38 (0.88 - 2.16)) or IVH (1.38 (0.96 - 1.98)) was similar between the two groups. Necrotising enterocolitis (NEC) ≥stage 2 was significantly higher in permissive BP support group infants (1.65 (1.07 - 2.50)). There was no difference in mortality or IVH between the two BP management approaches. Active BP support may reduce NEC. This should be investigated prospectively in large multicentre randomised studies.

Prophylactic Administration with Methylene Blue Improves Hemodynamic Stabilization During Obstructive Jaundice–Related Diseases’ Operation: a Blinded Randomized Controlled Trial

ObjectivesPatients with obstruction jaundice are at a high risk of hypotension and need high volume of fluids and a high dose of catecholamine to maintain organ perfusion during operation procedure. All these likely contribute to high perioperative morbidity and mortality. The aim of the study is to evaluate the effects of methylene blue on the hemodynamics in patients undergoing surgeries associated with obstructive jaundice. DesignA prospective, randomized, and controlled clinical study. SettingThe enrolled patients randomly received 2 mg/kg of methylene blue in saline or saline (50 ml) before anesthesia induction. The primary outcome was the frequency and dose of noradrenaline administration to maintain mean arterial blood pressure over 65 mmHg or > 80% of baseline, and systemic vascular resistance (SVR) over 800 dyne/s/cm5 during operation. The secondary outcomes were liver and kidney functions, and ICU stay. PatientsSeventy patients were enrolled in the study and randomly assigned to receive either methylene blue or control (n = 35/group). ResultsFewer patients received noradrenaline in the methylene blue group when compared with the control group (13/35 vs 23/35, P = 0.017), and the noradrenaline dose administrated during operation was reduced in the methylene blue group when compared with the control group (0.32±0.57 mg vs 1.787±3.51 mg, P = 0.018). The blood level of creatinine, glutamic oxalacetic transaminase, and glutamic–pyruvic transaminase after the operation was reduced in the methylene blue group when compared with the control group. ConclusionsProphylactic administration of methylene blue before operation associated with obstructive jaundice improves hemodynamic stability and short-term prognosis. QuestionMethylene blue use prevented refractory hypotension during cardiac surgery, sepsis, or anaphylactic shock. It is still unknown that methylene blue on the vascular hypo-tone associated with obstructive jaundice. FindingsProphylactic administration with methylene blue improved peri-operative hemodynamic stability, and hepatic and kidney function on the patients with obstructive jaundice. MeaningsMethylene blue is a promising and recommended drug for the patients undergoing the surgeries of relief obstructive jaundice during peri-operation management.

Comparison of clinical outcomes between active and permissive blood pressure management in extremely preterm infants

Background There remains uncertainty about the definition of normal blood pressure (BP), and when to initiate treatment for hypotension for extremely preterm infants. To determine the short-term outcomes of extremely preterm infants managed by active compared with permissive BP support regimens during the first 72 hours of life. Method This is a retrospective medical records review of 23+0–28+6 weeks’ gestational age (GA) infants admitted to neonatal units (NNU) with active BP support (aimed to maintain mean arterial BP (MABP) &gt;30 mmHg irrespective of the GA) and permissive BP support (used medication only when babies developed signs of hypotension) regimens. Babies admitted after 12 hours of age, or whose BP data were not available were excluded. Results There were 764 infants admitted to the participating hospitals; 671 (88%) were included in the analysis (263 active BP support and 408 permissive BP support). The mean gestational age, birth weight, admission temperature, clinical risk index for babies (CRIB) score and first haemoglobin of infants were comparable between the groups. Active BP support group infants had consistently higher MABP and systolic BP throughout the first 72 hours of life (p&lt;0.01). In the active group compared to the permissive group 56 (21.3%) vs 104 (25.5%) babies died, and 21 (8%) vs 51 (12.5%) developed &gt;grade 2 intra ventricular haemorrhage (IVH). Death before discharge (adjusted OR 1.38 (0.88 – 2.16)) or IVH (1.38 (0.96 – 1.98)) was similar between the two groups. Necrotising enterocolitis (NEC) ≥stage 2 was significantly higher in permissive BP support group infants (1.65 (1.07 – 2.50)). Conclusions There was no difference in mortality or IVH between the two BP management approaches. Active BP support may reduce NEC. This should be investigated prospectively in large multicentre randomised studies.

Anaesthetic management in a dog with constrictive pericarditis complicated with bi‐atrial enlargement and atrial fibrillation undergoing subtotal pericardiectomy

AbstractA 2‐year 8‐month‐old female dobermann presented for a recheck after previous crown reduction and vital pulp therapy. On cardiac auscultation, rapid and irregularly irregular heart rhythm and irregular and asynchronous pulses were detected. On electrocardiogram and transthoracic echocardiogram, findings were suggestive of constrictive pericarditis complicated with bi‐atrial enlargement and atrial fibrillation. Subtotal pericardiectomy was performed. The patient was premedicated with methadone (0.2 mg/kg intravenously), and anaesthesia was induced with midazolam (0.2 mg/kg intravenously) and propofol (60 mg), and maintained with isoflurane in oxygen. Constant‐rate infusions of fentanyl (0.1–0.2 µg/kg/min) and lidocaine (50 µg/kg/min) were administered. Dobutamine (1–5 µg/kg/min) helped to maintain mean arterial blood pressure above 65 mmHg. Fluid resuscitation and noradrenaline infusion (0.1 µg/kg/min) started after constriction was released to optimise preload. Haemodynamic support and ventricular rate control continued during the immediate postoperative period. Recovery from general anaesthesia was uneventful.

Effects of norepinephrine infusion during cardiopulmonary bypass on perioperative changes in lactic acid level (Norcal).

Hyperlactatemia, a problem reported in up to 30% of cardiac surgery patients, results from excessive production of or decreased clearance of lactate. It is typically a symptom of tissue hypoperfusion and may be associated with the prevalence of postoperative acute mesenteric ischemia and renal failure, or prolonged intensive care unit (ICU) and hospital stay, and increased 30-day mortality. Eighty cardiac surgery patients using cardiopulmonary bypass (CPB) were randomly assigned into either a placebo (n = 39) or norepinephrine 0.05-0.2 µg/kg/min (n = 41) as well as norepinephrine boluses during CPB to maintain mean arterial blood pressure (MAP) at 65 to 80 mm Hg. Patient assignments were done after receiving ethical approval to proceed. The primary result was the perioperative changes in lactic acid level. Secondary findings were also recorded, including hemodynamic variables, the incidence of vasoplegia, intraoperative hypotension, myocardial ischemia, the need for vasopressor support, postoperative complications, and mortality. The peak levels and perioperative changes in blood lactate during the first 24 postoperative hours, the number of patients who experienced early hyperlactatemia on admission to the ICU (Placebo: 46.2%, Norepinephrine: 51.2%, p = .650), vasoplegia, hemodynamic changes, incidences of intraoperative hypotension, myocardial ischemia, postoperative complications, and mortality rates were similar in the two groups. Patients in the norepinephrine group received lower intraoperative rescue norepinephrine boluses to maintain the target MAP (p = .039) and had higher MAP values during the CPB and intraoperative blood loss [mean difference [95% confidence interval]; 177 [20.9-334.3] ml, p = .027]. norepinephrine and placebo infusions during the CPB with the maintenance of MAP from 65 to 80 mmHg had comparative effects on the changes in blood lactate and incidence of vasoplegia after cardiac surgery. Norepinephrine infusion maintained higher MAP values during the CPB.

Early diagnosis of acute kidney injury subsequent to severe hypotension and fluid resuscitation in anaesthetized dogs

ObjectivesTo document changes in urinary biomarker concentration and conventional diagnostic tests of acute kidney injury (AKI) following hypotension and fluid resuscitation in anaesthetized dogs. Study designExperimental, repeated measures, prospective study. AnimalsA group of six male adult Greyhound dogs. MethodsFollowing general anaesthesia, severe hypotension was induced by phlebotomy, maintaining mean arterial blood pressure (MAP) < 40 mmHg for 60 minutes, followed by resuscitation with intravenous gelatine solution to maintain MAP > 60 mmHg for 3 hours. Following euthanasia, renal tissue was examined by light microscopy (LM) and transmission electron microscopy (TEM). Urinary and serum concentrations of neutrophil gelatinase-associated lipocalin (NGAL), cystatin C (CysC), and gamma-glutamyl transpeptidase (GGT), serum creatinine and urine output were measured at baseline and hourly until euthanasia. Data are presented as mean and 95% confidence interval and analysed using repeated measures analysis of variance with Dunnett’s adjustment, p < 0.05. ResultsStructural damage to proximal renal tubular cells was evident on LM and TEM. Urinary biomarker concentrations were significantly elevated from baseline, peaking 2 hours after haemorrhage at 19.8 (15.1–25.9) ng mL–1 NGAL (p = 0.002), 2.54 (1.64–3.43) mg mL–1 CysC (p = 0.009) and 2043 (790–5458) U L–1 GGT (p < 0.001). Serum creatinine remained within a breed-specific reference interval in all dogs. Urinary protein–creatinine ratio (UPC) was significantly elevated in all dogs from 1 hour following haemorrhage. Conclusions and clinical relevanceUrinary NGAL, CysC and GGT concentrations, and UPC were consistently elevated within 1 hour of severe hypotension, suggesting that proximal renal tubules are damaged in the earliest stage of ischaemia-reperfusion AKI. Measurement of urinary biomarkers may allow early diagnosis of AKI in anaesthetized dogs. Urinary GGT concentration and UPC are particularly useful as they can be measured on standard biochemistry analysers.

Sevoflurane or isoflurane anaesthesia? A prospective, randomised blinded clinical trial in horses undergoing elective surgery.

Isoflurane is the only volatile anaesthetic agent licensed for equine use in the United Kingdom, but sevoflurane is also commonly used. The two agents have rarely been compared for use in clinical elective surgery. This single centre, prospective, randomised, blinded clinical investigation recruited 101 healthy client owned horses undergoing elective surgery. Anaesthesia was standardised and horses randomly assigned to receive isoflurane (I) or sevoflurane (S) for maintenance of anaesthesia in 100% oxygen. Horses were ventilated to normocapnia and received intravenous fluid therapy and haemodynamic support with dobutamine to maintain mean arterial blood pressure above 60 mm Hg. Recovery was timed and video-recorded to allow offline evaluation by two experienced clinicians unaware of the volatile agent used. No post-anaesthetic sedation was administered. There was no significant difference between groups in terms of haemodynamic support required during anaesthesia nor in quality or duration of recovery. Inotropic support to maintain MAP above 60 mm Hg was required by 67 of 101 (67%) of horses. Five horses in the I group required additional ketamine or thiopentone to improve the plane of anaesthesia. Haemodynamic support needed during anaesthesia as well as the duration and quality of recovery were similar with isoflurane and sevoflurane.

Anaesthetic Management of Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy (CRS/HIPEC): A True Challenge To an Anaesthetist

Patients diseased with gynecological malignancies were believed untreatable with poor survival chances till hyperthermic intraperitoneal chemotherapy after capital cytoreductive surgery came into existence. Perioperative management of this patient, for a major surgery like CRS/HIPEC is complex and challenging. Major perioperative concerns in these patients include anesthetic challenges intraoperative fluid management, maintaining mean arterial blood pressure, thermoregulation electrolyte imbalances, significant blood loss and fluid shifts and renal toxicity after chemotherapeutic drugs administration. We report a case of 66 year old female diagnosed with carcinoma ovary with moderate ascites posted for cytoreductive surgery and HIPEC.

Controlled Hypotension for Functional Endoscopic Sinus Surgery: A Comparative study of Dexmedetomidine and Esmolol

Background: Functional endoscopic sinus surgery (FESS) requires effective control of bleeding for better visibility of the operating field and reduced risk of injury to the optic nerve or the internal carotid artery. Controlled hypotension is a technique used to limit intraoperative blood loss to provide the best possible field for surgery.&#x0D; Objectives: Our study is undertaken to evaluate the efficacy of dexmedetomidine as a hypotensive agent in comparison to esmolol in Functional Endoscopic Sinus Surgery (FESS).&#x0D; Methods: Sixty (60) patients 20 – 50 years of age, ASA I/II scheduled for FESS were randomly assigned to two equal groups of 30 patients each. Patients of group D received dexmedetomidine 1µg/kg over 10 min before induction of anesthesia followed by 0.4 – 0.8 µg/kg/hr infusion during maintenance and group E received esmolol loading dose 1mg/kg was infused over one min followed by 0.4 – 0.8 mg/kg/hr infusion during maintenance to maintain mean arterial blood pressure (MAP) between (55 – 65 mmHg). The surgical field was assessed using Average Category Scale and average blood loss was calculated. Hemodynamic variables (MAP, HR); intraoperative fentanyl consumption and total recovery from anesthesia (Aldrete’s score ≥9) were recorded. Sedation score was determined at 10, 20, 30, 40 &amp; 60 min after tracheal extubation and time to first analgesic demand was also recorded.&#x0D; Results:In both group D and group E reached the desired MAP (55–65 mmHg) with no inter group difference in MAP or HR. Mean intraoperative fentanyl consumption was significantly lower in group D than group E. Recovery time to achieved Aldrete’s score ≥9 were significantly lower in group E compared with group D.The sedation score were significantly lower in group E compared with group D at 10 minutes, 20 minutes and 30 minutes postoperatively. Time to first analgesic demand was significantly longer in group D.&#x0D; Conclusion: The result of this study showed that both dexmedetomidine and esmolol can be used as agents for controlled hypotension and are effective in providing ideal surgical field during FESS. But dexmedetomidine offers the advantage of inherent analgesic, sedative and anesthetic sparing effect.&#x0D; Bangladesh J Otorhinolaryngol; April 2018; 24(1): 37-49

MON-236 EXTERNAL CARDIAC PACING REVERSES OLIGURIC ACUTE KIDNEY INJURY IN A CARDIAC SURGICAL PATIENT (CASE REPORT)

Acute kidney injury (AKI) is a common complication of cardiac surgery, and is associated with increased morbidity and mortality. It may have multiple causes including intraoperative renal ischaemia and reperfusion due to cardiopulmonary bypass, low postoperative cardiac output, and nephrotoxic drugs. Bradycardia as a cause of AKI has rarely been reported. We describe a cardiac surgical patient in whom onset of bradycardia on postoperative day 3 led to AKI, which then promptly resolved with external cardiac pacing. A 78-year old man underwent two vessel coronary artery bypass grafting with bioprosthetic aortic valve replacement and mitral valve repair, with a total cardiopulmonary bypass duration of 181 minutes. Postoperative AKI was attributed to prolonged intraoperative hypotension and the need for inotropic support for 6 hours postoperatively to maintain mean arterial blood pressure >65mmHg. By day 2, the serum creatinine had risen from 100umol/L preoperatively (estimated glomerular filtration rate 60mL/min/1.73m2) to 263umol/L, before falling slightly to 240umol/L early on day 3. Throughout this period, urine output was >2L/day, weight was stable at 1kg above the preoperative weight of 70kg, and serum potassium was between 4.8 and 5.3mmol/L. Late on day 3, a junctional bradyarrhythmia was noted on telemetry, 48 hours after external on-demand cardiac pacing had been ceased (with pacing wires left in situ). Urine output dropped to only 135mL in total over the next 12 hours, despite oral fluid resuscitation and intravenous furosemide. Median heart rate was 50 beats per minute, median blood pressure was 124/62mmHg, and the patient remained afebrile and alert. On day 4, serum creatinine had risen again to 354umol/L, and weight had increased by a further 2.5kg. External atrial pacing was recommenced, with a ventricular rate of 70 beats per minute, whereupon urine output increased immediately. Furosemide was ceased, and polyuria ensued with the creatinine plateauing at 336umol/L on day 5, before falling to baseline over the next 3 days. Pacing wires were removed on day 6 with the patient in atrial fibrillation at a ventricular rate of 80 beats per minute. There was no renal artery stenosis on Doppler imaging. Bradycardia, presumably with a secondary reduction in cardiac output, should be considered as a potential cause of AKI in the postoperative setting, especially if oligoanuria occurs. In this case, temporary resumption of external cardiac pacing led to complete renal recovery.

Comparison of the Effects of Minimal and High-Flow Anaesthesia on Cerebral Perfusion During Septorhinoplasty.

The aim of this study was to analyse the effects of minimal-and high-flow anaesthesia on cerebral oxygenation during septorhinoplasty with controlled hypotension using near-infrared spectroscopy. Eighty patients scheduled for septorhinoplasty under general anaesthesia with controlled hypotension were randomised into two groups: minimal-flow (MF) or high-flow (HF). Both groups received desflurane anaesthesia to maintain bispectral index values at 40%-50% and 0.25-0.5 μg kg-1 min-1 i.v. remifentanyl infusion to maintain mean arterial blood pressure between 55 and 65 mmHg. The MF group received 5 L min-1 of fresh gas flow for the first 10 mins then the gas flow was reduced 0.4 L min-1. The HF group received 2 L min-1 of fresh gas flow throughout. Haemodynamic parameters and cerebral oxygen saturation were measured. There were no statistical differences in demographic variables, duration of anaesthesia and surgery, time to extubation and proceeding to an Aldrete score of 9. There were no statistical differences in haemodynamic parameters, end-tidal CO2 and cerebral oxygen saturation. The amount of desflurane used in the MF group was significantly lower than that used in the HF group (30.5±9.8 mL vs. 48.5±12.1 mL; p<0.05). MF and HF anaesthesia did not lead to any difference in cerebral oxygen saturation in patients undergoing septorhinoplasty with controlled hypotension. MF anaesthesia may thus be used as safely as HF anaesthesia is.

Anesthetic management of a dog with severe subaortic stenosis and mitral valve disease complicated with atrial fibrillation undergoing ovariohysterectomy

The anesthetic management in patients with subaortic stenosis and mitral valve disease should involve intensive monitoring and the anesthesiologist’s main concern is to ensure oxygen delivery and tissue perfusion. Since anesthetic procedures in such patients are rare, there is no previous report about the anesthetic management. A 5.5-year old, 32-kg Boxer, suffering a severe heart disease due to a final stage subaortic stenosis and mitral insufficiency, was anesthetized for an ovariohysterectomy to remove an ovarian tumor that was producing high-volume ascites. Methadone (0.3 mg kg−1) was administered intramuscularly (IM) for pre-anesthetic medication, etomidate (1.3 mg kg−1) and midazolam (0.2 mg kg−1) were used for the induction of anesthesia and after endotracheal intubation, anesthesia was maintained with sevoflurane vaporized in oxygen and air. Fentanyl (5–10 μg kg−1 h−1) and paracetamol (15 mg kg−1) were administered to improve analgesia. Previous persistent atrial fibrillation was refractory to medication (digoxin, diltiazem, and pimobendan) and continued during the anesthetic procedure. Dobutamine (1.5–5 μg kg−1 minute−1) helped to maintain mean arterial blood pressure above 60 mmHg. Epidural morphine (0.1 mg kg−1) and incisional bupivacaine (2 mg kg−1) were administered at the end of surgery to provide postoperative analgesia. Anesthesia was otherwise uneventful, and recovery was considered excellent.

Randomized Open-Labelled Comparative Evaluation of the Efficacy of Nitroglycerine, Esmolol and Dexmedetomidine in Producing Controlled Hypotension in Spine Surgeries.

Aim:This study was designed to evaluate the efficacy of nitroglycerine (NTG), esmolol, and dexmedetomidine (DEX) as hypotensive agents in decreasing intraoperative blood loss by producing controlled hypotension in posterior spine surgeries.Materials and Methods:Sixty patients aged 18–60 years, the American Society of Anesthesiologists physical status Classes I and II of either gender, were randomly assigned into three groups to receive either: NTG (0.01%) at the rate of 3–10 μg.kg-1.min-1 after positioning without a prior loading dose in Group N, esmolol 500 μg.kg-1 loading dose over 1 min before induction of anesthesia followed by 50–300 μg.kg-1.min-1 infusion in Group E, and DEX 1 μg.kg-1 over 10 min before induction followed by 0.2–0.7 μg.kg-1.h-1. infusion in Group D to maintain mean arterial blood pressure (MAP) between 60 and 65 mmHg. The three groups were compared for the achievement of target MAP, intraoperative blood loss, reversibility of hypotensive state, quality of surgical field, emergence time, and postextubation sedation score.Statistical Analysis:Analysis of variance was used for intergroup analysis, and for multiple comparisons, Bonferroni post hoc test was applied. P < 0.05 was considered statistically significant.Results:Patients in Group D and Group E achieved the target MAP with better heart rate control as compared to Group N. The intraoperative blood loss was significantly lesser in Group D (P < 0.001). The time to hypotension reversal and emergence time was prolonged in Group D (P < 0.001). The mean quality of surgical field score was statistically insignificant among the three groups. The mean Ramsay Sedation Scores were significantly higher in Group D compared to Groups N and E at 20th and 40th min postextubation (P < 0.001) with no significant intergroup difference at 60th min postextubation (P = 0.130).Conclusion:Continuous infusion of DEX is an effective and safe method of producing controlled hypotension by achieving the target MAP, minimizing blood loss, and maintaining superior hemodynamics in comparison with NTG and esmolol in posterior spine surgeries.

Abstract 187: Effects of Anesthetic Agents on the Hemodynamic Stabilization and Long Term Survival in an Experimental Model of Hemorrhagic Shock

Background: We investigated the cardiovascular responses to acute bleeding and shed blood restoration under different anesthetic agents, and their effects on long-term survival rate after hemorrhagic shock in rats, after our initial pilot study suggested differences between anesthetics. Methods: Sprague Dawley rats (both genders) were randomized to receive either intraperitoneal ketamine/xylazine (K/X, 90 mg/kg and 10 mg/kg; n=12), or isoflurane (5% isoflurane induction and 2% maintenance in room air; n=12) for anesthesia. Blood was withdrawn from the carotid artery to maintain mean arterial blood pressure (MBP) at 30 mm Hg for one hour, followed by 30 min of resuscitation with shed blood. Rats remained anesthetized for another 30 min before they were allowed to recovery and survive for 6 weeks. Hemodynamics were monitored during the surgical procedure. Results: During the shock phase, the total withdrawn blood volume (expressed as % of estimated total blood volume) to maintain MBP at 30 mmHg was significantly higher in the isoflurane group (51 ± 1.5 %) compared to the K/X group (45.3 ± 1.8 %; p=0.023). The diastolic internal dimension of the left ventricle, which indicated circulating intravascular blood volume, was significantly larger in the isoflurane group at the end of 1 hour of the shock phase (4.5 ± 0.2 mm compared to 3.5 ± 0.2 mm in K/X group; p=0.0003) and at 1 hour after initiation of shed blood reinfusion (6.3 ± 0.2 mm compared to 5.3 ± 0.3 in K/X group; p=0.014). Recovery of blood pressure during the resuscitation phase was significantly improved in the isoflurane group compared to the K/X group. The survival rate at 6 weeks was 1 of 12 (8.3%) in rats receiving K/X and 10 of 12 (83.3%) in rats receiving isoflurane (p &lt; 0.001). Histology demonstrated brain infarction in the 1 surviving rat receiving K/X; no brain infarction in the 10 surviving rats that received isoflurane at 6 weeks. No infarction was detected in heart, lung, liver or kidneys in all surviving rats. Conclusions: These results suggest that isoflurane stabilizes the cardiovascular response to acute blood lose and benefits the perfusion of tissue, which resulted in significantly higher long term survival rate and improved blood pressure response to resuscitation, without end-organ infarction.

Clinical evaluation of constant rate infusion of alfaxalone\u2013medetomidine combined with sevoflurane anesthesia in Thoroughbred racehorses undergoing arthroscopic surgery

BackgroundAlfaxalone has a number of pharmacological properties which are desirable for constant rate infusion (CRI). Previously, the co-administration of alfaxalone and medetomidine is shown to be suitable for short-term anesthesia in horses. However, the use of alfaxalone–medetomidine CRI with inhalational anesthesia under surgical procedures have not been investigated in clinical cases. The aim of the present study was to evaluate the clinical efficacy of alfaxalone–medetomidine CRI in sevoflurane-anesthetized Thoroughbred racehorses undergoing arthroscopic surgery. Sevoflurane requirement, cardiovascular function, and induction/recovery quality were compared between horses maintained with sevoflurane in combination with medetomidine CRI (3 µg/kg/h) (Group M; n = 25) and those maintained with sevoflurane in combination with alfaxalone–medetomidine CRI (0.5 mg/kg/h and 3 µg/kg/h, respectively) (Group AM; n = 25).ResultsThe mean end-tidal sevoflurane concentrations were significantly lower in Group AM (1.8 ± 0.2%) than in Group M (2.4 ± 0.1%). The mean dobutamine infusion rate required for maintaining mean arterial blood pressure within the target values (60–80 mmHg) was significantly lower in Group AM (0.53 ± 0.20 µg/kg/min) than in Group M (0.85 ± 0.32 µg/kg/min). Induction and recovery scores were not significantly different between two groups. However, excitatory response during recovery were observed in five horses in Group AM. The mean plasma alfaxalone concentrations were stable throughout the maintenance period (0.77 ± 0.12 to 0.85 ± 0.13 µg/mL), and decreased significantly immediately after standing (0.32 ± 0.07 µg/mL).ConclusionsAlfaxalone–medetomidine CRI reduced sevoflurane requirement by approximately 26% with good maintenance of cardiopulmonary function in Thoroughbred racehorses undergoing arthroscopic surgery. Sevoflurane in combination with alfaxalone–medetomidine CRI may be a clinically effective anesthetic technique for Thoroughbred racehorses. However, 20% of horses administered alfaxalone showed remarkable excitatory response during recovery. Greater attention to excitatory response may be advisable if alfaxalone is used for induction or maintenance of anesthesia. A larger study is needed to explore the clinical relevance of these findings.

Controlled Hypotension for Functional Endoscopic Sinus Surgery: A Comparative study between Dexmedetomidine versus Esmolol

Background: Functional endoscopic sinus surgery (FESS) requires effective control of bleeding forbetter visibility of the operating field and reduced risk of injury to the optic nerve or the internal carotidartery. Controlled hypotension is a technique used to limit intraoperative blood loss to provide the bestpossible field for surgery. Objectives: Our study is undertaken to evaluate the efficacy of dexmedetomidine as a hypotensive agentin comparison to esmolol in Functional Endoscopic Sinus Surgery (FESS). Method: Sixty (60) patients 20 – 50 years of age, ASA I/II scheduled for FESS were equally randomlyassigned to two equal groups of 30 patients each. Patients of group D received dexmedetomidine 1μg/kgover 10 min before induction of anesthesia followed by 0.4 – 0.8 μg/kg/hr infusion during maintenanceand group E received esmolol loading dose 1mg/kg was infused over one min followed by 0.4 – 0.8 mg/kg/hr infusion during maintenance to maintain mean arterial blood pressure (MAP) between (55 – 65mmHg). The surgical field was assessed using Average Category Scale and average blood loss wascalculated. Hemodynamic variables (MAP, HR); intraoperative fentanyl consumption and total recoveryfrom anesthesia (Aldrete’s score e”9) were recorded. Sedation score was determined at 10, 20, 30, 40 &amp; 60min after tracheal extubation and time to first analgesic demand was also recorded. Results: In both group D and group E reached the desired MAP (55 – 65 mmHg) with no intergroupdifference in MAP or HR. Mean intraoperative fentanyl consumption was significantly lower in group Dthan group E. Recovery time to achieved Aldrete’s score e”9 were significantly lower in group E comparedwith group D. The sedation score were significantly lower in group E compared with group D at 10minutes, 20 minutes and 30 minutes postoperatively. Time to first analgesic demand was significantlylonger in group D. Conclusion: The result of this study showed that both dexmedetomidine and esmolol can be used asagents for controlled hypotension and are effective in providing ideal surgical field during FESS. Butdexmedetomidine offers the advantage of inherent analgesic, sedative and anesthetic sparing effect. JBSA 2018; 31(2): 67-74

Oral clonidine: an effective adjuvant in functional endoscopic sinus surgery

Background: A comparative study to evaluate the efficacy of intravenous Dexmedetomidine as a hypotensive agent in comparison to oral Clonidine in Endoscopic Nasal Surgery or Functional Endoscopic Sinus Surgery (FESS).Methods: Forty patients ASA I or II scheduled for Endoscopic Nasal Surgery were equally randomly assigned to receive either dexmedetomidine 1μg/Kg over 10 min before induction of anesthesia followed by 0.5μg/Kg/h infusion during maintenance (Group D), or oral Clonidine (Group C) 2µg/kg with minimal water 1 hour prior starting of surgery. Rescue bolus doses of Propofol (10mg/dose) were given to maintain mean arterial blood pressure (MAP) between (50-70mmHg). General anesthesia was maintained with Isoflurane 1%-2%. The surgical field was assessed using Average Category Scale. Hemodynamic variables (MAP and HR) were recorded at 10 minutes interval.Results: Both group C and group D reached the desired MAP (50-70mmHg) with no intergroup differences in HR but a statistically significant lower MAP was noticed in group C. The quality of the surgical field in the range of MAP (50-70mmHg) were 2-3 as per average category Scale with significantly lower score in Group C. Mean intraoperative propofol consumption was significantly higher in group D than C group.Conclusions: Both Dexmedetomidine or oral clonidine with isoflurane are safe agents for controlled hypotension, but oral clonidine provides lower MAP and better surgical field. Compared with Dexmedetomidine, oral clonidine offers the advantage of less consumption of propofol.

Controlled mechanical ventilation with constant positive end-expiratory pressure and alveolar recruitment manoeuvres during anaesthesia in laterally or dorsally recumbent horses

ObjectiveTo compare the effects of controlled mechanical ventilation (CMV) and constant positive end-expiratory pressure (PEEP) and interposed recruitment manoeuvres (RMs) with those of CMV without PEEP on gas exchange during general anaesthesia and the early recovery period. Study designProspective, randomized clinical trial. AnimalsA total of 48 Warmblood horses undergoing elective surgery in lateral (Lat) (n = 24) or dorsal (Dors) (n = 24) recumbency. MethodsPremedication (romifidine), induction (diazepam and ketamine) and maintenance (isoflurane in oxygen) were identical in all horses. Groups Lat- CMV and Dors-CMV (each n = 12) were ventilated using CMV. Groups Lat-RM and Dors-RM (each n = 12) were ventilated using CMV with constant PEEP (10 cmH2O) and intermittent RMs (three consecutive breaths with peak inspiratory pressure of 60 cmH2O, 80 cmH2O and 60 cmH2O, respectively). RMs were applied as required to maintain PaO2 at > 400 mmHg (> 53.3 kPa). Dobutamine was given to maintain mean arterial blood pressure at > 60 mmHg. Physiological parameters were recorded every 10 minutes. Arterial blood gases were measured intra- and postoperatively. Statistical analyses were conducted using analyses of variance (anova),t tests and the Mann–Whitney U-test. ResultsHorses in Dors-RM had higher PaO2 values [478 ± 35 mmHg (63.7 ± 4.6 kPa)] than horses in Dors-CMV [324 ± 45 mmHg (43.2 ± 6 kPa)] during anaesthesia and the early recovery period. There were no differences between horses in groups Lat-CMV and Lat-RM. Other measured parameters did not differ between groups. Conclusions and clinical relevanceVentilation with CMV, constant PEEP and interposed RM provided improved arterial oxygenation in horses in dorsal recumbency that lasted into the early recovery period, but had no benefit in horses in lateral recumbency. This mode of ventilation may provide a clinically practicable method of improving oxygenation in anaesthetized horses, especially in dorsal recumbency.

Does Early Goal-Directed Therapy Decrease Mortality Compared with Standard Care in Patients with Septic Shock?

BackgroundCurrent international guidelines for the treatment of patients with severe sepsis and septic shock recommend that patients receive targeted care to various physiologic endpoints, thereby optimizing tissue perfusion and oxygenation. These recommendations are primarily derived from a protocol published >15 years ago, which was viewed by many as complex and was therefore not widely adopted. Instead, many emergency physicians focused on the administration of early antibiotics, source control, aggressive fluid resuscitation, vasoactive medications as needed to maintain mean arterial blood pressure, and careful monitoring of these patients. The primary goal of this literature search was to determine if there is a mortality benefit to the early goal-directed protocol recommended by current international sepsis guidelines compared to current usual care. MethodsA MEDLINE literature search was performed for studies published between January 1, 2010 and December 31, 2015. Studies were limited to the English language, human randomized controlled trials, meta-analyses, prospective trials, and retrospective cohort trials that met specific keyword search criteria. Case reports, case series, and review articles were excluded. All selected articles then underwent a structured review by the authors. ResultsSeven thousand four hundred twenty studies were initially screened; after the final application of inclusion and exclusion criteria, 10 studies were formally analyzed. Each study then underwent a rigorous review and evaluation from which a formal recommendation was made. ConclusionThere is no difference in mortality between current usual care and the goal-directed approach recommended by current international guidelines for patients with severe sepsis and septic shock.