Target Mean Arterial Blood Pressure Research Articles

Differences in the Practice of Traumatic Spinal Cord Injury Management Among Spine Surgeons in Saudi Arabia.

This study aims to explore the ease of adopting clinical practice guidelines (CPGs) in managing traumatic spinal cord injury (TSCI) among spine surgeons, with particular focus on the use of steroids, high-dependency unit, early spinal cord decompression, and maintaining a target mean arterial blood pressure (MAP). We conducted a cross-sectional study among the practicing spinal surgeons in Saudi Arabia and included surgeons from neurosurgical and orthopedic backgrounds. The study period was from April to June 2020. The respondents provided sociodemographic data, training background, years of experience, and their clinical practices in managing TSCI via a survey tool constructed based on a literature review. The data were analyzed to evaluate the association between a surgeon's demographics and clinical practices. Ninety-eight spinal surgeons responded, comprising 40% of the practicing spine surgeon population in Saudi Arabia. The only area where the neurosurgical spine and orthopedic spine surgeons' practices differed significantly was maintaining MAP within a target range. Other differences between practices were not statistically significant. The authors also found a significant correlation between the surgeon's school of training and their experience concerning steroids administration. On the other hand, the surgeon experience and volume of treated TSCI cases correlated significantly with admission to a high-dependency unit. The adoption of CPGs remains a challenge to many spinal surgeons. Neurosurgeons are more into keeping the MAP at certain target, whereas the school of training and surgeon experience were the largest determinants of the surgeon's practice in managing TSCI in Saudi Arabia. As the variability in managment among spine surgeons remains a challenge, international and national spine societies are expected to build clinical practice guidelines from the limited existing literature.

Protocol for an individual patient data meta-analysis on blood pressure targets after cardiac arrest.

BackgroundHypotension is common after cardiac arrest (CA), and current guidelines recommend using vasopressors to target mean arterial blood pressure (MAP) higher than 65 mmHg. Pilot trials have compared higher and lower MAP targets. We will review the evidence on whether higher MAP improves outcome after cardiac arrest.MethodsThis systematic review and meta‐analysis will be conducted based on a systematic search of relevant major medical databases from their inception onwards, including MEDLINE, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL), as well as clinical trial registries.We will identify randomised controlled trials published in the English language that compare targeting a MAP higher than 65–70 mmHg in CA patients using vasopressors, inotropes and intravenous fluids. The data extraction will be performed separately by two authors (a third author will be involved in case of disagreement), followed by a bias assessment with the Cochrane Risk of Bias tool using an eight‐step procedure for assessing if thresholds for clinical significance are crossed. The outcomes will be all‐cause mortality, functional long‐term outcomes and serious adverse events. We will contact the authors of the identified trials to request individual anonymised patient data to enable individual patient data meta‐analysis, aggregate data meta‐analyses, trial sequential analyses and multivariable regression, controlling for baseline characteristics. The certainty of the evidence will be assessed by the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. We will register this systematic review with Prospero and aim to redo it when larger trials are published in the near future.ConclusionsThis protocol defines the performance of a systematic review on whether a higher MAP after cardiac arrest improves patient outcome. Repeating this systematic review including more data likely will allow for more certainty regarding the effect of the intervention and possible sub‐groups differences.

A comparison between propofol, dexmedetomidine and nitroglycerin as hypotensive agents and their effect on blood loss in functional endoscopic sinus surgery (FESS)

Background & objective: Patients with chronic sinusitis, not responding to medical treatment are managed with functional endoscopic sinus surgery (FESS) by ENT specialists. The surgery demands a bloodless field for its success. Even minimal amount of blood can obscure the surgical field to the operating surgeon. We compared three drugs, propofol, dexmedetomidine, and nitroglycerin as hypotensive agents and their effect on blood loss in FESS.
 Methodology: Our study included sixty adult patients scheduled for FESS at Ain Shams University hospitals from September 2018 to September 2019. All patients were ASA I and II and they were distributed into three groups in a random manner, twenty patients in each group. Patients in Group D were administered dexmedetomidine 1 μg/kg as a loading dose over 10 min (in 100 ml normal saline) just after induction, then 0.5 μg/kg/h was infused. Group P patients were administered propofol infusion 8 mg/kg/h. Group N patients were administered nitroglycerin infusion of 2 μg/kg/min. Hemodynamic parameters were recorded every 15 min. We used bleeding score to examine the quality of operating field. We recorded the time to achieve target mean arterial blood pressure. Duration of operation was recorded.
 Results: In Groups D and P, our target of mean arterial pressure of 55-65 mmHg was achieved. The hypotensive drugs used in these groups offered good quality of surgical field and shorter duration of surgery. Group D also achieved target blood pressure faster than Group P with significantly lower heart rate in Group D.
 Conclusion: Dexmedetomidine and propofol had more favorable effects for attaining the desired blood pressure than nitroglycerin with lower heart rate in dexmedetomidine group. Dexmedetomidine and propofol were associated with less bleeding and shorter duration of surgery in patients undergoing FESS. Also dexmedetomidine was faster in achieving target blood pressure than propofol.
 Trial Registry: PACTR202202877370804
 Abbreviations: FESS - Functional endoscopic sinus surgery; CSF - Cerebrospinal fluid; GABA - γ-aminobutyric acid’ MAP - Mean arterial blood pressure
 Key words: Anesthesia; Anesthesia, General; Endoscopy / methods; Humans; Propofol; Dexmedetomidine; Nitroglycerin; Controlled hypotension; FESS.
 Citation: Saleh SAEM, Awad HGS, Shonoda AMF, ElShorbagy MS, Doaa Mohammed Kamal ElDin DMK. A comparison between propofol, dexmedetomidine and nitroglycerin as hypotensive agents and their effect on blood loss in functional endoscopic sinus surgery (FESS). Anaesth. pain intensive care 2022;26(3):338-346. DOI: 10.35975/apic.v26i3.1908
 Received: March 10, 2022; Reviewed: April 07, 2022; Accepted: May 05, 2022
 Background & objective: Patients with chronic sinusitis, not responding to medical treatment are managed with functional endoscopic sinus surgery (FESS) by ENT specialists. The surgery demands a bloodless field for its success. Even minimal amount of blood can obscure the surgical field to the operating surgeon. We compared three drugs, propofol, dexmedetomidine, and nitroglycerin as hypotensive agents and their effect on blood loss in FESS.
 Methodology: Our study included sixty adult patients scheduled for FESS at Ain Shams University hospitals from September 2018 to September 2019. All patients were ASA I and II and they were distributed into three groups in a random manner, twenty patients in each group. Patients in Group D were administered dexmedetomidine 1 μg/kg as a loading dose over 10 min (in 100 ml normal saline) just after induction, then 0.5 μg/kg/h was infused. Group P patients were administered propofol infusion 8 mg/kg/h. Group N patients were administered nitroglycerin infusion of 2 μg/kg/min. Hemodynamic parameters were recorded every 15 min. We used bleeding score to examine the quality of operating field. We recorded the time to achieve target mean arterial blood pressure. Duration of operation was recorded.
 Results: In Groups D and P, our target of mean arterial pressure of 55-65 mmHg was achieved. The hypotensive drugs used in these groups offered good quality of surgical field and shorter duration of surgery. Group D also achieved target blood pressure faster than Group P with significantly lower heart rate in Group D.
 Conclusion: Dexmedetomidine and propofol had more favorable effects for attaining the desired blood pressure than nitroglycerin with lower heart rate in dexmedetomidine group. Dexmedetomidine and propofol were associated with less bleeding and shorter duration of surgery in patients undergoing FESS. Also dexmedetomidine was faster in achieving target blood pressure than propofol.
 Trial Registry: PACTR202202877370804
 Abbreviations: FESS - Functional endoscopic sinus surgery; CSF - Cerebrospinal fluid; GABA - γ-aminobutyric acid’ MAP - Mean arterial blood pressure
 Key words: Anesthesia; Anesthesia, General; Endoscopy / methods; Humans; Propofol; Dexmedetomidine; Nitroglycerin; Controlled hypotension; FESS.
 Citation: Saleh SAEM, Awad HGS, Shonoda AMF, ElShorbagy MS, Doaa Mohammed Kamal ElDin DMK. A comparison between propofol, dexmedetomidine and nitroglycerin as hypotensive agents and their effect on blood loss in functional endoscopic sinus surgery (FESS). Anaesth. pain intensive care 2022;26(3):338-346. DOI: 10.35975/apic.v26i3.1908
 Received: March 10, 2022; Reviewed: April 07, 2022; Accepted: May 05, 2022

The Use of the Comma Sign and Tissue for Recognition, Reduction, and Stability During Arthroscopic Repair of Combined Anterosuperior Cuff Tears

Background: The comma sign is a useful marker for combined retracted supraspinatus and subscapularis tears. It was first described by the group of Burkhart as a “composite ligamentous structure” of the rotator interval attached to the retracted subscapularis. However, Neyton and coworkers suggested that the ruptured superior part of subscapularis is pulled upward by supraspinatus retraction. This video illustrates the value of “comma” recognition for reduction and repair stability. We feel that the comma tissue can be a composition of rotator interval ligaments with or without superior subscapularis contribution depending on an associated cleavage tear. Indications: Patients with retracted anterosuperior tears, unless muscle quality is poor (Goutallier classification ≥3). Understanding of the comma tissue is difficult but of crucial importance to assess complex anterosuperior cuff tears for reduction and repair with stability by maintaining and integrating this comma link into the repair construct. Technique Description: Arthroscopic setup includes beach chair position, armholder, cerebral saturation monitoring (target mean arterial blood pressure of about 70 mm Hg). Previously described circumferential portals were used for a repair with a double row construct (4 medial anchors: 2.5 for subscapularis; 1.5 for supraspinatus) and 2 lateral anchors. The superior boarder of subscapularis as well as the retracted capsular layer of supraspinatus was reduced and fixed using a lasso loop technique. Key stages are (1) tendon manipulation with 2 traction sutures; (2) tendon release; (3) comma reduction; (4) footprint preparation (burr, microfracture); (5) retrograde suture passing; (6) knot tying, knotless lateral row; and (7) a close surgeon to physiotherapist rehabilitation link (6 weeks passive to 90°, no resistance training for 3-6 months). Results: Senior author’s (S.B.) series: 32 anterosuperior tears over 4 years (mean age: 62 years, 48-73 years), minimum follow-up 1 year showed good results (mean SSV: 85% [preop. 35%], range: 40%-95%; mean Constant: 82 [preop. 30], range: 40-90). One major complication (cutibacterium infection; brick layer; workers compensation; invalidity demand; Constant/Subjective Shoulder Value both 40) and minor temporary stiffness at 3 months (8 patients; 22%). Conclusion: Adequate reduction and comma integration into a solid repair construct, as well as responsible rehabilitation surveillance, deliver successful results after technically intricate anterosuperior repairs.

Premedication for Induced Hypotension in Functional Endoscopic Sinus Surgeries: Intravenous Dexmedetomidine Infusion vs Oral Metoprolol vs Placebo: A Comparative Study.

Background:Controlled hypotension has been used to reduce bleeding and the need for blood transfusions and provide a satisfactory bloodless surgical field. In this double-blind, randomized controlled trial, we are comparing intravenous (i.v.) dexmedetomidine infusion and oral metoprolol as a premedication for controlled hypotension in functional endoscopic sinus surgery (FESS) for evaluating surgical field visibility.Subjects and Methods:A total of 90 patients undergoing FESS were randomly divided into three groups of 30 each. Group A received intraoperative i.v. infusion of dexmedetomidine (loading 1 μg.kg−1 over 10 min followed by the maintenance of 0.2–0.5 μg.kg−1.h−1), Group B received oral metoprolol 50 mg on night and 2 h before surgery as a premedication, and Group C was taken as a control group and patients received oral placebo tablet as premedication and intraoperative normal saline infusion. General anesthesia was given using sevoflurane. Intraoperative target mean arterial blood pressure was set 55–65 mmHg. Various parameters were recorded and statistically compared.Results:The three groups were statistically comparable in demographics. Quality of surgical field was better in Group A compared to other two groups. Total blood loss was also less in Group A. The incidence of adverse reactions was more in Group A.Conclusion:Dexmedetomidine provides a better surgical field compared to oral metoprolol in FESS along with the desired hemodynamics with lesser blood loss and better outcome.

Hypotension and Hypocapnia During General Anesthesia in Piglets: Study of S100b as an Acute Biomarker for Cerebral Tissue Injury.

Hypotension and/or hypocapnia might increase general anesthesia (GA)-related neuromorbidity in infants, but safe levels of perioperative blood pressure are poorly defined. Serum protein S100b has been used as screening, monitoring, and prediction tool in the management of patients with traumatic brain injury. Using an animal model, we investigated serum S100b as an acute biomarker of cerebral hypoperfusion and cerebral cell dysfunction during hypotension, hypocapnia, or combined hypotension/hypocapnia during GA. Fifty-seven sevoflurane-midazolam anesthetized piglets aged 4 to 6 weeks were randomly allocated to control (n=9), hypotension (n=18), hypocapnia (n=20), or combined hypotension and hypocapnia (n=10). Hypotension (target mean arterial blood pressure: 35 to 38 or 27 to 30 mm Hg) was induced by blood withdrawal and nitroprusside infusion, and hypocapnia by hyperventilation (target PaCO2: 28 to 30 and 23 to 25 mm Hg). Serum S100b and albumin were measured at baseline, before and 60 minutes after the interventions, and following 60-minute recovery. Serum S100b concentrations decreased over time (P=0.001), but there was no difference in S100b between control piglets and those exposed to hypotension, hypocapnea, or a combination of the both (P=0.105). Albumin decreased in all 4 groups (P=0.001). S100b did not increase following 60 minutes of systemic hypotension and/or hypocapnia during GA in piglets. In this setting, the use of S100b as a biomarker of cerebral cell tissue dysfunction cannot be supported.

Compliance with the European trauma guidelines: An observational single centre study

ObjectivesThe European trauma guidelines were developed to assist clinicians in the early phase of trauma management to diagnose and treat coagulopathy and bleeding. This study aimed to determine compliance with these European trauma guidelines in a French referral trauma centre. MethodsMedical charts of trauma patients with an injury severity score≥16 admitted between January 2013 and December 2014 were reviewed. Compliance with 21 recommendations in the first 24-hours of patient management was assessed. ResultsThere were 145 patients with median ISS of 34 [IQR 25–41]. A good level of compliance (i.e. applied in≥80% of patients) was identified for nine recommendations, inconsistent compliance (i.e. applied in 50 to 79% of patients) for six recommendations, including fibrinogen levels at hospital admission and achievement of a target mean arterial blood pressure (MAP)>80mmHg in patients with major bleeding and TBI (55.5%), and poor compliance (i.e. applied in<50% of patients) for another six recommendations. Poorly applied recommendations included early measurement of lactate or base deficit (32%), early administration of tranexamic acid (18%), and achievement of normocapnia in patients with TBI undergoing invasive ventilation (3%). ConclusionsIn a referral trauma centre, nine of the 21 evaluable recommendations in the European trauma guidelines were applied in≥80% of patients. Early diagnosis and treatment of trauma-related coagulopathy was identified as an area for significant practice improvement. In patients with TBI, efforts should be made to achieve the targeted MAP and to maintain normocapnia.

Metaboreflex-mediated hemodynamic abnormalities in individuals with coronary artery disease without overt signs or symptoms of heart failure.

This study was devised to investigate the effect of coronary artery disease (CAD) without overt signs of heart failure on the cardiovascular responses to muscle metaboreflex activation. We hypothesized that any CAD-induced preclinical systolic and/or diastolic dysfunction could impair hemodynamic response to the metaboreflex test. Twelve men diagnosed with CAD without any sign or symptoms of heart failure and 11 age-matched healthy control (CTL) subjects participated in the study. Subjects performed a postexercise muscle ischemia (PEMI) test to activate the metaboreflex. They also performed a control exercise recovery test to compare data from the PEMI test. The main results were that the CAD group reached a similar mean arterial blood pressure response as the CTL group during PEMI. However, the mechanism by which this response was achieved was different between groups. In particular, CAD achieved the target mean arterial blood pressure by increasing systemic vascular resistance (+383.8 ± 256.6 vs. +91.2 ± 293.5 dyn·s-1·cm-5 for the CAD and CTL groups, respectively), the CTL group by increasing cardiac preload (-0.92 ± 8.53 vs. 5.34 ± 4.29 ml in end-diastolic volume for the CAD and CTL groups, respectively), which led to an enhanced stroke volume and cardiac output. Furthermore, the ventricular filling rate response was higher in the CTL group than in the CAD group during PEMI ( P < 0.05 for all comparisons). This study confirms that diastolic function is pivotal for normal hemodynamics during the metaboreflex. Moreover, it provides evidence that early signs of diastolic impairment attributable to CAD can be detected by the metaboreflex test. NEW & NOTEWORTHY Individuals suffering from coronary artery disease without overt signs of heart failure may show early signs of diastolic dysfunction, which can be detected by the metaboreflex test. During the metaboreflex, these subjects show impaired preload and stroke volume responses and exaggerated vasoconstriction compared with controls.

Intravenous clonidine as a part of balanced anaesthesia for controlled hypotension in functional endoscopic sinus surgery: A randomised controled trial.

Background and Aims:Controlled hypotension with balanced anaesthesia minimises blood loss. This study was done to evaluate the effectiveness of intravenous clonidine as a single bolus dose to establish controlled hypotension during functional endoscopic sinus surgery (FESS).Methods:This randomised, double-blind, placebo-controlled study was done in a tertiary hospital in India. Sixty American Society of Anesthesiologists physical status I and II patients (18–65 years) undergoing FESS were randomly allocated to one of the two groups. Placebo group (group A, n = 30) received sterile water whereas the clonidine group (group B, n = 30) received 3μg/kg of clonidine intravenously, 30 min prior to induction of anaesthesia. The primary outcome was to achieve a target mean arterial blood pressure (MAP) of 55–65 mmHg intraoperatively. The secondary outcomes measured were requirement of additional fentanyl and metoprolol, intra-operative blood loss, surgeon's opinion on the surgical field, pain, sedation score and complications requiring treatment.Results:Target MAP was easily achieved in clonidine group as against the placebo group (P < 0.001). Significant reduction in intra-operative blood loss (P = 0.0449), a better surgical site scoring (P = 0.02), less requirement of additional hypotensive drugs and good analgesia (P = 0.01) were seen in clonidine group. The complication rates were similar in both the groups.Conclusion:Clonidine is effective in achieving controlled hypotension in patients undergoing FESS. It reduces intra-operative blood loss, requirement of additional hypotensive drugs, improves the surgical field and offers good analgesia without significant side effects.

Efficacy of adding fixed dose dexmedetomidine to nitroglycerin for controlled hypotension in functional endoscopic sinus surgery

Background Functional endoscopic sinus surgery (FESS) is a surgical procedure during which all possible measures to minimize bleeding should be considered, as even small amount of blood may obstruct vision. Controlled hypotension is one of these measures used to limit intraoperative blood loss to provide the best possible surgical field. The aim of this study was to compare the effect of a fixed dose of dexmedetomidine (DEX) and nitroglycerin (NTG) with NTG alone on hemodynamic parameters, NTG dose, surgeon satisfaction, and blood loss during controlled hypotensive anesthesia in FESS. Patients and methods Fifty patients of both sexes, classified as American Society of Anesthesia physical status I and II, aged between 20 and 50 years, and candidates for FESS were randomly allocated into two groups by using the sealed envelope method. Group I (n=25) received hypotensive anesthesia with NTG and group II (n=25) received hypotensive anesthesia with NTG and DEX. DEX 1 μg/kg over 10 min was given, and then infused by a syringe pump at a fixed rate of 0.5 μg/kg/h before induction of anesthesia in group II only. After induction and intubation NTG was infused in both groups and titrated to obtain a target mean arterial blood pressure (MAP) of 55–65 mmHg. The MAP and heart rate (HR) were measured at baseline, and then periodically. The following parameters were also recorded: duration of surgical interference (time from the beginning to the end of surgical intervention), blood loss volume, surgeon satisfaction, time to achievement of the target MAP, time to reversibility of MAP to baseline, and the highest dose of NTG needed to reach target MAP. Results There was no significant difference between two groups regarding demographic data, basal hemodynamics, duration of surgical intervention, American Society of Anesthesia physical status, surgeon satisfaction, and all measurements of MAP except time of intubation, which was significantly less in group II. On the other hand, there was a significant difference between both groups regarding HR, time to achievement and reversibility of MAP, blood loss volume, and the highest dose of NTG needed to reach the target MAP, as all of these measurements were significantly lower in group II. Conclusion DEX (1 μg/kg bolus, followed by 0.5 μg/kg/h infusion) and NTG is superior to NTG alone in rapid achievement of target MAP with lower HR and lower NTG doses and in reducing blood loss volume during FESS.

Effects of dobutamine hydrochloride on cardiovascular function in horses anesthetized with isoflurane with or without acepromazine maleate premedication.

OBJECTIVE To determine the effects of acepromazine maleate premedication on cardiovascular function before and after infusion of dobutamine hydrochloride for 30 minutes in isoflurane-anesthetized horses. ANIMALS 6 healthy adult horses. PROCEDURES Each horse was anesthetized once following premedication with acepromazine (0.02 mg/kg, IV) administered 30 minutes prior to anesthetic induction (ACP+ treatment) and once without premedication (ACP- treatment). Anesthesia was induced with IV administration of xylazine hydrochloride (0.8 mg/kg), ketamine hydrochloride (2.2 mg/kg), and diazepam (0.08 mg/kg). Horses were positioned in right lateral recumbency, and anesthesia was maintained via inhalation of isoflurane delivered in oxygen. End-tidal isoflurane concentration was adjusted to achieve a target mean arterial blood pressure of 60 mm Hg (interquartile range [25th to 75th percentile], 57 to 63 mm Hg) for at least 15 minutes. Cardiac index, oxygen delivery index, and femoral arterial blood flow indices were determined 60 minutes after anesthetic induction (baseline). Dobutamine was then infused to achieve a target mean arterial blood pressure of 80 mm Hg (interquartile range, 76 to 80 mm Hg). Data collection was repeated 30 minutes after the start of dobutamine infusion for comparison with baseline values. RESULTS Complete data sets were available from 5 of the 6 horses. Dobutamine administration resulted in significant increases in oxygen delivery and femoral arterial blood flow indices but no significant change in cardiac index for each treatment. However, at baseline or 30 minutes after the start of dobutamine infusion, findings for the ACP+ and ACP- treatments did not differ. CONCLUSIONS AND CLINICAL RELEVANCE In isoflurane-anesthetized horses, dobutamine administration increased oxygen delivery and femoral arterial blood flow indices, but these changes were unaffected by premedication with acepromazine.

Oral nifedipine as a premedication for induced hypotension in functional endoscopic sinus surgery (FESS)

ObjectiveTo evaluate the effects of oral nifedipine as pretreatment, quality of surgical field and amount of hypotensive agent during functional endoscopic sinus surgery (FESS) under general anesthesia.MethodsSixty patients ASA I or II scheduled for FESS were randomly allocated into two equal groups. Oral nifedipine 20 mg was given one hour before induction of anesthesia (nifedipine) group and placebo. In the other group (control), all the patients received standard anesthesia and monitoring. Nitroglycerin (GTN) was administrated in a dose of 2 μg/kg/min after induction of anesthesia till it achieved a target mean arterial blood pressure (MAP) of 50–60 mmHg, followed by a continuous i.v. infusion (1 μg/kg/min) intraoperative when needed. Hemodynamic variables were recorded at baseline preoperatively, intraoperatively and till the end of operation. The surgical field score was assessed by average category scale (ACS) and intraoperative blood loss and amount of GTN was estimated. Emergence time and total recovery from anesthesia (Aldrete score ⩾9) were recorded.ResultsThere were no statistically significant differences between two groups with respect to the amount of blood loss and scores for a bloodless surgical field. Emergence time and time needed to achieve 9 of modified Aldrete score were significantly shorter in Control group than nifedipine group (4.46 ± 1.25 min and 7.46 ± 2 min versus 8 ± 1.62 min and 9.5 ± 2.41 min, respectively) (P < 0.01). MAP during hypotensive period showed no statistically significant difference (p > 0.05) but at 5 and 10 min after stoppage of hypotensive anesthesia, at the end of surgery and after recovery, MAP was significantly lower in nifedipine group than Control group (p < 0.01). Heart rate (HR) during hypotensive period showed no statistically significant difference (p > 0.05). At 5 and 10 min after stoppage of hypotensive anesthesia, at end of surgery and after recovery, HR was significantly lower in nifedipine group than Control group (p < 0.001). The amount of GTN used in nifedipine group was significantly lower than Control group (p < 0.001).ConclusionAdministration of a single preoperative dose of nifedipine (20 mg) can significantly reduce the blood loss during FESS and improves the visualization of the operative field and it also lowers the amount of GTN needed to achieve target hypotension.

Donation after circulatory death: a national survey of current practice in England in 2012.

In recent years, England has seen renewed interest in donation after circulatory death. Many national and local initiatives have been implemented to encourage and support donation after circulatory death. To assess whether practice is in line with published guidance, we conducted a national survey with regard to current donation after circulatory death practices, local guidelines, and views on the need to further develop a national standardized protocol for donation after circulatory death. Online survey. Lead physicians for intensive care or organ donation for every acute National Health Service trust in England delivering adult care between April and June 2012. Physicians were e-mailed a link to a structured online questionnaire regarding their experience and practice of donation after circulatory death, including local protocols, use of organ optimization, and the need for a national protocol. We received replies from 119 of 156 eligible trusts (76.3%) in England. Of these, 112 trusts (94%) have performed donation after circulatory death. Ninety-three trusts (78.1%) have a local donation after circulatory death protocol, and 89 trusts (74.7%) felt there should be a national donation after circulatory death protocol. All responding transplant centers had performed donation after circulatory death, 14 of 17 (82.3%) had a donation after circulatory death protocol with 14 of 17 respondents (82.3%) supporting a national protocol. Regarding organ optimization, 92 institutions (77.3%) used vasoactive drugs to achieve a target mean arterial blood pressure with 82 centers (68.9%) employing positive end-expiratory pressure and FIO2 to optimize oxygenation. Eight centers (6.7%) used heparin premortem compared with two of 17 transplant centers (11.8%). Two centers have used phentolamine to facilitate organ retrieval, with another five centers (4.2%) cannulating vessels premortem. Our survey revealed varying approaches and views toward donation after circulatory death across England. A greater than expected percentage use premortem cannulation, heparinization, and phentolamine despite current guidance in England to the contrary. The majority of institutions practicing donation after circulatory death with protocols in place favor the development of national guidelines, particularly with respect to organ optimization. We believe that such a protocol would help to address potential barriers to donation after circulatory death, which may lead to increased donation rates and improved outcomes.

Comparison of the hemodynamic effects of nitroprusside and remifentanil for controlled hypotension during endoscopic sinus surgery

Controlled hypotension (CH) is a well-established technique to decrease blood loss and improve surgical visibility. Although nitroprusside and remifentanil have been safely and effectively used for this purpose, the hemodynamic changes that occur during CH are unclear. This study compared the effects of nitroprusside and remifentanil on hemodynamics using a noninvasive cardiac output monitor (Cheetah NICOM(®); Cheetah Medical Inc., Maidenhead, Berkshire, UK) for endoscopic sinus surgery (ESS). Twenty-eight adult patients scheduled for ESS were randomly assigned to the nitroprusside group (n = 14) or remifentanil group (n = 14). After anesthesia induction, hypotension was induced with continuous infusion of nitroprusside or remifentanil at a target mean arterial blood pressure (MAP) of 60-70 mmHg. Cardiac index (CI), stroke volume index (SVI) and total peripheral resistance index (TPRI) were measured at 10-min intervals. The heart rate was higher and SVI was lower in the nitroprusside group than in the remifentanil group during CH. There were no significant differences in MAP, CI or TPRI between the two groups. Both nitroprusside and remifentanil reduced MAP and TPRI during CH compared with baseline values. However, there was no significant change in CI. Both nitroprusside and remifentanil were effective to induce CH and maintain CI during CH.

Evaluation of tissue oxygen saturation with near-infrared spectroscopy during experimental acute hemorrhagic shock and resuscitation in dogs

To evaluate tissue oxygen saturation (Sto2) by use of near-infrared spectroscopy in experimental acute hemorrhagic shock and resuscitation in dogs. 14 healthy adult purpose-bred Beagles. Dogs were anesthetized with isoflurane via facemask, anesthesia was maintained with propofol and rocuronium bromide, and dogs were mechanically ventilated to maintain normocapnia. Dogs were studied under normovolemia (baseline), hypovolemia with target mean arterial blood pressure < 40 mm Hg achieved and maintained steady for 10 minutes (hypovolemia T1), then 20 minutes later (hypovolemia T2), following resuscitation with shed blood (after transfusion), and after administration of 20 mL of hetastarch/kg (hypervolemia). Conditions were executed sequentially during a single anesthetic episode, allowing stabilization between states (10 minutes). Hemoglobin concentration, mean arterial blood pressure, arterial blood gas concentrations, cardiac index, oxygen delivery indexed to body surface area, and Sto2 were monitored. From baseline to hypovolemia T1, there was a significant reduction in mean ± SD oxygen delivery index (619 ± 257 mL/min/m(2) to 205 ± 76 mL/min/m(2)) and Sto2 (94 ± 4.4% to 78 ± 12.2%). Following resuscitation, Sto2 (80 ± 8.5% vs 92 ± 6.45%) and oxygen delivery index (211 ± 73 mL/min/m(2) vs 717 ± 221 mL/min/m(2)) significantly increased, returning to baseline values. Hypervolemia had no effect on Sto2 or oxygen delivery index. A strong correlation (r = 0.97) was detected between mean oxygen delivery index and Sto2 across all time points. Under the conditions of this study, there was a strong correlation between Sto2 and oxygen delivery, suggesting that Sto2 may be used to estimate oxygen delivery.

Optimizing the surgical field in pediatric functional endoscopic sinus surgery: A new evidence-based approach

Objectives To conduct the first prospective randomized controlled study 1) evaluating the possibility of improving the quality of the operative field and to provide a bloodless functional endoscopic sinus surgery (FESS) in children through total intravenous anesthesia (TIVA) using remifentanil combined with propofol, and 2) testing the safety and efficacy of remifentanil in propofol-TIVA in inducing controlled hypotension in children at a target mean arterial blood pressure of 50 mm Hg. Study Design Randomized controlled trial. Setting General hospital. Subjects and Methods Seventy children underwent FESS under hypotensive general anesthesia with equal randomization into two groups. Group I received TIVA with remifentanil, whereas group II had balanced anesthesia (BA) with esmolol. Heart rate, blood pressure, operative time, blood loss, and quality of the surgical conditions were recorded. Results Intraoperative blood loss in the TIVA group was less than in the BA group. The quality and dryness of the surgical field in both the visual analogue scale and the six-point scale was significantly better in the TIVA group than in the BA group. Hypotension was sustained at the target mean arterial blood pressure of 50 mm Hg in the two groups, without any significant difference. Conclusion Improving the quality of the surgical field and providing a bloodless FESS in children is attainable with TIVA. TIVA using a combination of remifentanil and propofol is superior to BA, even with the use of additional potent hypotensive agents such as esmolol. Both techniques are safe and effective in inducing controlled hypotension in children at a target mean arterial blood pressure of 50 mm Hg.

Response of hypotensive dogs to dopamine hydrochloride and dobutamine hydrochloride during deep isoflurane anesthesia

To evaluate the dose-related cardiovascular and urine output (UrO) effects of dopamine hydrochloride and dobutamine hydrochloride, administered individually and in combination at various ratios, and identify individual doses that achieve target mean arterial blood pressure (MAP; 70 mm Hg) and cardiac index (CI; 150 mL/kg/min) in dogs during deep isoflurane anesthesia. 10 young clinically normal dogs. Following isoflurane equilibration at a baseline MAP of 50 mm Hg on 3 occasions, dogs randomly received IV administration of dopamine (3, 7, 10, 15, and 20 microg/kg/min), dobutamine (1, 2, 4, 6, and 8 microg/kg/min), and dopamine-dobutamine combinations (3.5:1, 3.5:4, 7:2, 14:1, and 14:4 microg/kg/min) in a crossover study. Selected cardiovascular and UrO effects were determined following 20-minute infusions at each dose. Dopamine caused significant dose-dependent responses and achieved target MAP and CI at 7 microg/kg/min; dobutamine at 2 microg/kg/min significantly affected only CI values. At any dose, dopamine significantly affected UrO, whereas dobutamine did not. Target MAP and CI values were achieved with a dopamine-dobutamine combination at 7:2 microg/kg/min; a dopamine-related dose response for MAP and dopamine- and dobutamine-related dose responses for CI were identified. Changes in UrO were associated with dopamine only. In isoflurane-anesthetized dogs, a guideline dose for dopamine of 7 microg/kg/min is suggested; dobutamine alone did not improve MAP. Data regarding cardiovascular and UrO effects indicated that the combination of dopamine and dobutamine did not provide greater benefit than use of dopamine alone in dogs.

Comparison of Blood Loss according to Different Anesthetic Technique for Total Hip Replacement

The mean blood loss is about 500−1,700 ml by general anesthesia technique in total hip replacement (THR) and the amount of blood loss is dependent on the degree of induced hypotension. We performed this study to evaluate the differences on the amount of blood loss and the number of transfused patients according to different anesthetic technique under the similar hypotension level. Methods: Forty-seven patients of ASA physical status class 1, 2 and 3, scheduled for THR, were randomly assigned into epidural anesthesia group (E group), combined general epidural anesthesia group (GE group) and general anesthesia group (G group). G group was maintained with sevoflurane anesthesia and the monitoring of central and arterial blood pressure was performed. The remifentanil (0.1μg/kg/min) was infused continuously for the target mean arterial pressure of 60 ± 5 mmHg. GE group received general anesthesia with the same technique of G group and epidural anestheia was combined after general anesthesia. The remifentanil (0.1μg/kg/min) was infused continuously for the target mean arterial blood pressure of 60 ± 5 mmHg. E group received epidural anesthesia with 0.75% ropivacaine and additional bolus dose of local anesthetics was injected if the mean arterial blood pressure did not reach 60 ± 5 mmHg. Results: The mean volume of blood loss and the number of transfused patients was significantly less in E or GE group at 24 hour after surgery (P ＜ 0.05), however we could not find any significant differences during intraoperative period. Conclusions: Epidural or combined general epidural anesthesia technique is a good method to reduce bleeding and the number of transfused patients.

Vasopressors and intestinal mucosal perfusion after cardiac surgery: Norepinephrine vs. phenylephrine

To evaluate the potential differential effects of norepinephrine, an alpha1-, beta1-, and beta2-receptor agonist, to the alpha1-agonist phenylephrine on jejunal mucosal perfusion, gastric-arterial PCO2 gradient, and the global splanchnic oxygen demand-supply relationship after cardiac surgery. A randomized, prospective, interventional crossover study. A university cardiothoracic intensive care unit. Ten patients were studied during propofol sedation and mechanical ventilation after uncomplicated coronary artery bypass surgery. Each patient received randomly and sequentially norepinephrine (0.052+/-0.009 microg/kg/min) and phenylephrine (0.50+/-0.22 microg/kg/min) to increase mean arterial blood pressure by 30%. Data on jejunal mucosal perfusion, jejunal mucosal hematocrit, and red blood cell velocity (laser Doppler flowmetry) as well as gastric-arterial Pco2 gradient (tonometry) and splanchnic oxygen extraction were obtained before (control) and during a 30-min drug infusion period after the target mean arterial blood pressure was reached. The procedure was sequentially repeated for the second vasopressor. Both drugs induced a 40-46% increase in systemic vascular resistance with no change in cardiac index. Neither jejunal mucosal perfusion, jejunal mucosal hematocrit, red blood cell velocity, nor gastric-arterial Pco2 gradient was affected by any of the vasopressors. Splanchnic oxygen extraction increased from 38.2% to 43.1% (p<.001) with norepinephrine and from 39.3% to 47.5% (p<.001) with phenylephrine. This increase was significantly more pronounced with phenylephrine compared with norepinephrine (p<.05). Mixed venous-hepatic vein oxygen saturation gradient increased with both drugs (p<.01), and the increase was more pronounced with phenylephrine (p<.05). Splanchnic lactate extraction was not significantly affected by any of the vasopressors. Phenylephrine induced a more pronounced global alpha1-mediated splanchnic vasoconstriction compared with norepinephrine. Neither of the vasoconstrictors impaired perfusion of the gastrointestinal mucosa in postcardiac surgery patients. The lack of norepinephrine-induced, alpha1-mediated impairment of gastrointestinal perfusion is not explained by a beta2-mediated counteractive vasodilation but instead by possible mucosal autoregulatory escape.

Sodium nitroprusside metabolism in children during hypothermic cardiopulmonary bypass.

Ten children, aged 1-7 yr, presenting for repair of complex congenital heart lesions, were prospectively studied. A ketamine, halothane/isoflurane, and fentanyl anesthetic was used. After initiation of hypothermic cardiopulmonary bypass, sodium nitroprusside (SNP) was titrated as necessary to maintain a target mean arterial blood pressure of 35-60 mm Hg. Blood samples drawn immediately prior to starting SNP infusion, every 15 min during infusion, and at 1, 4, and 24 h postinfusion were analyzed for whole blood cyanide (CN-) and serum thiocyanate (SCN-). Blood gas analysis was performed every 30 min during SNP infusion. A maximum CN- level > or = 1.0 micrograms/mL was observed in two children; four others had maximum CN- levels between 0.5 micrograms/mL and 1.0 micrograms/mL (normal, < 0.2 micrograms/mL). No child had a clinically important increase of SCN- subsequent to SNP infusion. There was substantial variability in observed CN- accumulation during SNP infusion. CN- levels during the first 60 min correlated with the average SNP rate of administration (P = 0.02). Cyanide levels rapidly decreased after termination of SNP infusion and were undetectable 4 h postinfusion. Despite the short-term increase of CN- level, no child showed biochemical signs of toxicity (acidosis or increased mixed venous oxygen tension).