Intraoperative Mean Arterial Blood Pressure Research Articles

Association between intraoperative blood pressure and postoperative delirium in elderly hip fracture patients.

BackgroundOne possible area of intervention to prevent postoperative delirium (PD) is intraoperative blood pressure management. However, the relationship between intraoperative blood pressure and PD is unclear. A secondary analysis of a RCT study examining the PD risk over the range of absolute intraoperative mean arterial blood pressure (MAP) readings and the corresponding relative changes from preoperative baseline level was performed to determine the role of MAP on PD.MethodsNonparametric locally weighted quadratic polynomial smoothing (LOESS) regression explored the pattern of PD risk at postoperative day 2 as a function of mean surgery MAP (msMAP) and percent change of msMAP from baseline in 103 elderly hip fracture patients. Segment-linear logistic regression models were then constructed to determine the odds ratios (OR) of PD over the observed range of these msMAP measures, adjusting for potential confounds.ResultsTwenty-three patients (22%) developed PD on day 2. LOESS regression revealed a j-shaped association between absolute levels of msMAP and PD risk. When msMAP was ≥80 mmHg, higher msMAP imparted greater PD risk (OR = 2.28 per 10 mmHg msMAP increase; 95% CI: 1.11–4.70), while higher msMAP was associated with lower PD risk (OR = 0.19 per 10 mmHg increase; CI: 0.05–0.76) if msMAP was <80 mmHg. There was no statistically significant relationship between PD risk and average percent change from baseline in these msMAP measures.ConclusionIn elderly hip fracture patients, both very high and very low levels of msMAP were associated with significantly increased risk of PD.

Does tramadol or bupivacaine intraincisional infiltration with inguinal canal block during hernioplasty change the postoperative pain profile?

Objective The study aimed to evaluate the effect of inguinal canal block together with intraincisional injection of tramadol against bupivacaine 0.25% on both intraoperative and postoperative pain relief in patients undergoing inguinal hernioplasty under general anesthesia. Patients and methods The study was conducted on 60 male patients scheduled for elective inguinal hernioplasty under general anesthesia in the Kasr Al-Ainy School of Medicine. Patients were randomly allocated into three groups: group C [control group (n = 20)], group B [bupivacaine 0.25% group (n = 20)], and group T [tramadol group (n = 20)]. During the surgery, the mean arterial blood pressure and the heart rate were traced every 5 min. The total intraoperative fentanyl requirement, postoperative visual analogue score and sedation scores, and nausea and vomiting were recorded; patient and surgeon satisfaction were assessed. Results The intraoperative mean arterial blood pressure, heart rate, and fentanyl requirement were statistically lower in both the bupivacaine and the tramadol groups compared with the control group. The postoperative visual analogue score was statistically lower in both the bupivacaine and the tramadol groups compared with the control group. Postoperative nausea and vomiting were statistically higher in the tramadol group compared with the control group and the bupivacaine groups. The scoring of postoperative patient satisfaction was statistically higher in the tramadol group compared with the bupivacaine and the control groups. Conclusion The study offered a new technique using tramadol as a locally infiltrated drug during inguinal hernioplasty aiming to decrease intraoperative and postoperative pain together with reducing analgesic needs to minimum during and after the operation with the consequent beneficial reduction of narcotic side effects.

Comparative Study of two Doses of Intrathecal Dexmedetomidine Versus Fentanyl as Adjuvant to Hyperbaric Bupivacaine Spinal Anesthesia

Abstract The aim of this study was to evaluate the effect of addition two different doses of dexmedetomidine or fentanyl to intrathecal hyperbaric bupivacaine on spinal block characteristics, intraoperative hemodynamics, the blood glucose level and postoperative pain. 100 patients ASA I and II, ages 20 -60 years old undergoing elective surgeries below the umbilicus under spinal anesthesia were divided into four groups (n=25 each): Patients were randomly allocated into four equal groups (n= 25, each): Group I: received 3 mL of 0.5% hyperbaric bupivacaine +0.5ml normal saline. Group II: received 3 mL of 0.5% hyperbaric bupivacaine plus 3 μg dexmedetomidine (diluted in 0.5ml of normal saline) intrathecal. Group III: received 3 mL of 0.5% hyperbaric bupivacaine plus 5 μg dexmedetomidine (diluted in 0.5ml of normal saline) intrathecal. Group IV: received 3 mL of 0.5% hyperbaric bupivacaine plus 25 μg fentanyl (0.5ml) intrathecal. intraoperative heart rate and mean arterial blood pressure showed no statistical significant differences between the study groups, patients in group II, III and IV had significantly longer sensory and motor block times than patients in group I. The time of first request of postoperative analgesia was statistically significantly shorter in group I compared to the other groups. Pain scores were higher in group I compared to the other groups. Postoperative blood glucose level was only statistically significantly higher in group II compared to the other groups. Both intrathecal dexmedetomidine and fentanyl are associated with prolongation of sensory and motor block, with stable hemodynamics, minimal effect on blood glucose level, and better postoperative analgesia, compared to intrathecal bupivacaine alone. Key Words: Spinal anesthesia, bupivacaine, dexmedetomidine, fentanyl

Awakening Properties of Isoflurane, Sevoflurane, and Desflurane in Pediatric Patients After Craniotomy for Supratentorial Tumours

The aim of this prospective, comparative, randomized study was to compare the inhalational anesthetics isoflurane, sevoflurane, and desflurane in pediatric patients undergoing craniotomy for excision of supratentorial tumors. We assessed early postoperative recovery outcome, intraoperative hemodynamics, and degree of brain swelling, as well as postoperative vomiting and shivering. Sixty patients scheduled for supratentorial brain tumor excision, were randomly allocated into 1 of 3 groups (20 patients each); isoflurane, sevoflurane, and desflurane group. After IV induction of anesthesia, maintenance was achieved using the inhalational anesthetic according to the allocated group. Tracheal extubation time was the primary endpoint. The secondary endpoints included: emergence time and the interval time needed to reach Aldrete score ≥9, intraoperative degree of brain swelling, intraoperative heart rate and mean arterial blood pressure, as well as postoperative vomiting and shivering. The mean emergence time, extubation time, and the interval required to reach Aldrete score 9 were significantly shorter in the desflurane and sevoflurane groups than the isoflurane group. No statistically significant changes in the 3 groups regarding intraoperative brain swelling, hemodynamics, and postoperative shivering or vomiting were noted. Desflurane and sevoflurane can be used to facilitate early emergence from anesthesia in neurosurgical pediatric patients. Emergence times are shorter with desflurane or sevoflurane than with isoflurane. The patients who received desflurane or sevoflurane have similar intraoperative and postoperative incidence of adverse effects compared with those who received isoflurane. Thus, desflurane and sevoflurane can be considered as suitable for emergence in pediatric neurosurgical anesthesia.

Acute sialadenitis of parotid gland: Anaesthesia mumps

Acute sialadenitis of parotid gland: Anaesthesia mumps

Dexmedetomidine, morphine, propofol vs midazolam, morphine, propofol for conscious sedation in rhinoplasty under local anesthesia. A prospective, randomized study

BackgroundMonitored anesthesia care (MAC) has been proposed as one of the suitable techniques for rhinoplasty. In this study our aim was to compare the effects of dexmedetomidine with morphine and propofol vs benzodiazepines with morphine and propofol as adjuncts to local anesthesia – on analgesia, sedation, respiratory and hemodynamics variables and surgeon and patient satisfaction.MethodsIn this prospective, double-blind, comparative study, 60 patients undergoing rhinoplasty by local anesthesia randomly received intravenous sedation of either: dexmedetomidine (Dex group) or midazolam (Mid group) in combination with morphine and propofol. Level of sedation was assessed by using the Observer’s Assessment Alertness/Sedation Scale (OAA/S). Pain on local anesthesia injection was assessed by a visual analog scale. Surgeon’s satisfaction also can be assessed by using a 3-grades score, the surgeon assessed the quality of surgical bleeding. Mean Arterial Pressure (MAP) and heart rate (HR) were assessed and recorded. Patients’ satisfaction, visual analog scale for intraoperative pain, and total amount of propofol used intraoperatively. Adverse effects were also recorded.ResultsIn Mid group patients were earlier to reach adequate sedation level than in Dex group, but they felt more pain either on local anesthetic injection or during operation. Intraoperative mean arterial blood pressure and heart rate in Dex group were lower than their baseline values and the corresponding values in Mid group. The total amount of propofol needed for Mid group was much higher than in Dex group. Patient satisfaction was higher in Dex group. Time of surgery was longer in Mid group. Both groups were similar in sedation recovery and ward discharge times, as well as, incidence of side effects.ConclusionDexmedetomidine sedation with morphine and propofol in rhinoplasty performed under local anesthesia was associated with shorter surgery time, greater patient and surgeon satisfaction, and lower pain scores with no adverse effects, when compared to midazolam sedation with morphine and propofol.

The effect of anterior palatine blocks on bleeding in hereditary hemorrhagic telangiectasia nasal surgery

When combined with local sphenopalatine (SP) injection and moderate hypotension, transoral or transcutaneous local injection of the anterior palatine (AP) vessels reduces intraoperative bleeding in hereditary hemorrhagic telangiectasia (HHT) patients undergoing nasal surgery. Retrospective chart review of 55 consecutive HHT patients undergoing a bevacizumab injection for recalcitrant epistaxis. Nineteen patients received local injections to only the SP vasculature, and 36 patients received AP and SP injections. Main outcome variable was estimated blood loss during nasal surgery. Independent variables included sex, age, epistaxis severity score, surgical techniques (including laser), and blood pressure parameters (baseline, preinduction, and postintubation). The mean blood loss in HHT patients receiving SP injections alone was 111 mL, whereas it was 22 mL for those receiving both AP + SP injections. This difference between groups approached statistical significance (P = .075). Blood pressure parameters were similar in both groups with no appreciable difference between intraoperative systolic and mean arterial blood pressure. The addition of either sublabial or transcutaneous AP injection to the standard SP block markedly reduces blood loss in HHT epistaxis nasal surgery.

Effects of high thoracic epidural anesthesia on mixed venous oxygen saturation in coronary artery bypass grafting surgery

BackgroundTo investigate possible effects of high thoracic epidural anesthesia (HTEA) on mixed venous oxygen saturation (SvO2) in coronary artery bypass grafting surgery (CABGS).Material/MethodsSixty-four patients scheduled for CABGS were randomly assigned to either test (HTEA) or control group. Standard balanced general anesthesia was applied in both groups. Mean arterial blood pressure (MAP), heart rate (HR), oxygen saturation (SpO2), central venous pressure (CVP), cardiac output (CO), cardiac index (CI), systemic vascular resistance (SVR), pulmonary vascular resistance (PVR), mean pulmonary arterial pressure (PAP), pulmonary capillary wedge pressure (PCWP), pulmonary compliance (C), bispectral index (BIS), body temperature, SvO2, hematocrit values were recorded before induction. Postoperative hemodynamic changes, inotropic agent, need for vasodilatation, transfusion and additional analgesics, recovery score, extubation time, visual analogue scale (VAS) values, duration of stay in intensive care unit (ICU) and hospital were recorded.ResultsStudy groups were similar in SpO2, CVP, PCWP, PAP, C, body temperature, BIS values, development of intraoperative bradycardia. In HTEA group, intraoperative MAP, SVR, PVR, need for transfusion were lower, whereas CO, CI, SvO2, hematocrit values were higher (p<0.05). Postoperative MAP, HR, hypertension development, need for vasodilatator, transfusion, analgesics, extubation time, recovery data, duration of stay in ICU, hospital were lower in HTEA group (p<0.05). VAS score decreased in 30 minutes and 12 hours following extubation in HTEA and control group, respectively.ConclusionsHTEA may improve balance between oxygen presentation and usage by suppressing neuroendocrin stress response; provide efficient postoperative analgesia, more stabile hemodynamic, respiratory conditions, lower duration of stay in ICU, hospital.

Effects of preoperative β-blocker on blood loss and blood transfusion during spinal surgeries with sodium nitroprusside-controlled hypotension

Background:The present study sought to determine whether premedication with oral β-blocker before hypotensive anesthesia with sodium nitroprusside could improve the quality of surgical field, decrease the blood loss, and decrease the need for homologous blood transfusion and duration of surgery.Methods:Eighty patients scheduled for spinal fixation surgery were included in a prospective, randomized, double-blinded study. Patients were classified into two groups: Group I received oral atenolol 50 mg twice one day before surgery; and Group II received placebo tablets identical in appearance to atenolol tablets for the same period and interval. All patients in both the groups received intraoperative sodium nitroprusside (SNP) as a hypotensive agent. Hemodynamic variables, amount of sodium nitroprusside used, quality of surgical field, and the amount of homologous blood transfusion and blood loss were compared between groups.Results:Heart rate and amount of SNP used were significantly less (P<0.0001) in the atenolol group, but no significant difference was found in intraoperative mean arterial blood pressure (MABP) between the two groups. The time of surgeries was significantly shorter in Group I than in Group II (185±15.21 vs 225±12.61 min), P<0.0001. The quality of surgical field was better in Group I than in Group II in all times of measurements, P<0.0001. The amount of blood loss and the amount of packed red blood cells transfused were significantly less in Group I than in Group II, P<0.0001. No clinically significant complications were observed in either group.Conclusion:Premedication with oral atenolol 50 mg twice/day for one day before hypotensive anesthesia with SNP during spinal surgeries seems to be clinically safe and effective to reduce heart rate, amount of SNP used, amount of blood loss, and amount of blood transfused with better quality of surgical field.

The role of the trigeminocardiac reflex in postoperative hearing function in non-vestibular schwannoma cerebellopontine angle tumors

The trigeminocardiac reflex (TCR) is a common event during skull base surgery that can lead to intraoperative arterial hypotension and bradycardia. Arterial hypotension associated with TCR can be a negative prognostic factor for postoperative auditory function and ipsilateral tinnitus in patients undergoing surgery for vestibular schwannoma (VS). In this study, the contribution of TCR to postoperative auditory function in non-VS cerebellopontine angle (CPA) tumor surgery was investigated. From a consecutive series of 102 patients with CPA tumors, we studied the occurrence of TCR and its influence on postoperative auditory function in patients with non-VS tumors. Pre- and postoperative auditory function, pre- and intraoperative mean arterial blood pressure, as well as preoperative medication, tumor size, and occurrence of TCR were evaluated. Of the 35 patients evaluated, four developed intraoperative TCR, of whom one was preoperatively deaf. Preoperative functional hearing was detected in 30/35 patients (85.7%): preoperative deafness was documented in one patient in the TCR group and in four patients in the non-TCR group. Of the 30 patients with preoperative functional hearing, 1/3 (33.3%) patients in the TCR group and 23/27 (85.2%) patients in the non-TCR group had functional hearing postoperatively. When patients with large tumors and functional, hearing were considered, only 33.3% of patients in the TCR group and 77.8% of patients in the non-TCR group remained within the same hearing classes following surgical treatment ( p = 0.1573). TCR may be a negative prognostic factor for postoperative auditory function in patients with large, non-VS CPA tumors.

Bupivacaine scalp nerve block: hemodynamic response during craniotomy, intraoperative and post-operative analgesia

Abstract Background: Noxious stimuli during craniotomy may induce hypertension and tachycardia, giving rise to morbidity in patients with intracranial hypertension. Craniotomy is followed by moderate level of postoperative pain. Objective: Evaluate the effectiveness of scalp block on hemodynamic response to noxious stimuli, intraoperative fentanyl requirement and post-operative analgesia. Methods: Sixty patients undergoing elective craniotomy were randomly assigned to receive a scalp block with either 0.5% bupivacaine or 0.25% bupivacaine and 1:200,000 adrenaline (group A and B) or normal saline with 1:200,000 adrenaline (group C). Fentanyl 0.5 mcg/kg was administered for hemodynamic control. Intraoperative mean arterial blood pressure (MAP), heart rate (HR), fentanyl doses, and post-operative pain scores were recorded. Post-operative analgesia was provided by patient-controlled analgesia (PCA) morphine for 24 hours. Results: MAP was greater in group C than group A during pinning and incision (p &lt;0.05), and was greater in group C than group B during pinning, incision and craniotomy (p &lt;0.05). HR differences were not statistically significant between all groups (p &gt;0.05). Intraoperative fentanyl requirement was significantly greater in group C compared with group A and B (p &lt; 0.05). Pain score, time to the first morphine administration and total morphine consumption were not significantly different between all groups. Conclusion: Pre-incision scalp blocks using either 0.25% or 0.5% bupivacaine with 1:200,000 adrenaline were effective to prevent rising of MAP, but not HR in response to cranial pinning and skin incision, causing less intraoperative fentanyl requirement. However, they did not reduce post-craniotomy pain and morphine consumption.

Does Correcting the Numbers Improve Long-term Outcome?

Does Correcting the Numbers Improve Long-term Outcome?

Effect of Intraoperative Injection of 0.25% Bupivacaine with 1:200,000 Epinephrine on Intraoperative Blood Loss in FESS

This study was designed to compare differences in intraoperative blood loss, mean arterial blood pressure (MABP), and duration of surgery when 0.25% bupivacaine with 1:200000 epinephrine is injected, preoperatively, versus normal saline (NS), during functional endoscopic sinus surgery (FESS). A prospective, double-blind randomized placebo-controlled study was performed. Part I involved 46 patients who were infiltrated with 0.25% bupivacaine with 1:200000 epinephrine on one side of the nose and sterile NS on the other (control). Part II involved 30 patients infiltrated with 0.25% bupivacaine with 1:200000 epinephrine bilaterally and 30 patients with NS bilaterally (control). Patient demographics, preoperative MABP, intraoperative MABP, duration of surgery, and total estimated blood loss (EBL) were recorded for each side (Part I) and case (Part II). For part I, there were 46 patients (mean age, 49 years), 24 women and 22 men. MABP was 72 mmHg for each side (p = 0.97). Preoperative MABP was 93 mmHg. Duration of surgery was 48 minutes for epinephrine side and 45 minutes for control (p = 0.17). Total EBL was 185 mL for the epinephrine side and 197 mL for control (p = 0.53). For Part II, there were 60 patients (mean age, 56 years), 28 women and 32 men. The MABP was 77 mmHg for the epinephrine group and 72 mmHg for control (p = 0.048). Preoperative MABP was 100 mmHg for the epinephrine group and 97 mmHg for control (p = 0.37). Duration of surgery was 2.25 hours for the epinephrine group and 2.08 hours for control (p = 0.17). Total EBL was 589 mL for the epinephrine group and 538 mL for control (p = 0.64). There was no significant reduction in intraoperative blood loss during FESS when local anesthetic containing epinephrine was used compared with infiltration with NS. More importantly, Part II shows a significantly higher MABP associated with infiltration of epinephrine. Parts I and II did not show a significant difference in preoperative MABP or duration of surgery.

Should Intraoperative Hypercapnea or Hypercarbia Raise Concern in Neonates Undergoing Thoracoscopic Repair of Diaphragmatic Hernia of Bochdalek?

Better understanding of cardiopulmonary physiology in children with congenital diaphragmatic hernia of Bochdalek (CDH) has facilitated improved survival. In addition, it has allowed surgeons to employ minimally invasive techniques to their repair under conditions that might result in hypercarbia and/or recurrent pulmonary hypertension. Under institutional review board approval, the records of all neonates at a single institution who underwent thoracoscopic CDH (T-CDH) were reviewed with attention to the incidence of intraoperative hypercapnea (elevated end tidal CO(2)) or hypercarbia (increased PCO(2) by blood gas measurement) and any associated complications. From 2004 through 2007, 31 consecutive neonates, including those who had undergone extracorporeal membrane oxygenation, had T-CDH. CO(2) insufflation to 3 mm Hg was used until the viscera were reduced within the abdominal cavity. The operative technique and outcomes are described elsewhere. Preoperative analyses revealed a mean arterial PCO(2) of 53 +/- 11 torr and SaO(2) of 95 +/- 5%. The mean highest recorded intraoperative end-tidal CO(2) level was 64 +/- 13 and correlated poorly with the highest arterial PCO(2) (mean, 78 +/- 29 torr; range, 29-130). The mean lowest recorded intraoperative SaO(2) was 92 +/- 8% with only two values less than 88%. The average lowest intraoperative mean arterial blood pressure was 47 +/- 8 mm Hg (range, 34-70 mm Hg). No neonate received inhaled nitric oxide, intravenous buffer administration, or escalation of inotrope administration during the procedures nor did any experience recurrent pulmonary hypertension postoperatively. Hypercapnea and hypercarbia are common phenomena during T-CDH but do not appear to correlate with one another nor result in clinically evident recurrent pulmonary hypertension, hypoxemia, hypotension, need for support with vasoactive medications, inhaled nitric oxide, or buffering agents.

A comparison of epidural buprenorphine plus detomidine with morphine plus detomidine in horses undergoing bilateral stifle arthroscopy

ObjectiveTo compare the analgesic efficacy of buprenorphine plus detomidine with that of morphine plus detomidine when administered epidurally in horses undergoing bilateral stifle arthroscopy. Study designProspective, randomized, blinded clinical trial. AnimalsTwelve healthy adult horses participating in an orthopedic research study. Group M (n = 6) received morphine (0.2 mg kg−1) and detomidine (0.15 mg kg−1) epidurally; group B (n = 6) received buprenorphine (0.005 mg kg−1) and detomidine (0.15 mg kg−1) epidurally. MethodsHorses received one of two epidural treatments following induction of general anesthesia for bilateral stifle arthroscopy. Heart rate (HR), mean arterial blood pressure (MAP), end-tidal CO2 (Pe’CO2), and end-tidal isoflurane concentrations (E’Iso%) were recorded every 15 minutes following epidural administration. Post-operative assessment was performed at 1, 2, 3, 6, 9, 12, and 24 hours after standing; variables recorded included HR, respiratory rate (fR), abdominal borborygmi, defecation, and the presence of undesirable side effects. At the same times post-operatively, each horse was videotaped at a walk and subsequently assigned a lameness score (0-4) by three ACVS diplomates blinded to treatment and who followed previously published guidelines. Nonparametric data were analyzed using Wilcoxon’s rank-sum test. Inter- and intra-rater agreement were determined using weighted kappa coefficients. Statistical significance was set at p = 0.05. ResultsNo statistically significant differences were found between groups with respect to intra-operative HR, MAP, E’Iso%, or post-operative HR, gastrointestinal function and cumulative median lameness scores. Post-operative fR in group B [24 (12-30), median (range)] breaths per minute was significantly higher than in group M [18 (15-20)] breaths per minute, p = 0.04. Conclusions and clinical relevanceIn horses undergoing bilateral stifle arthroscopy, these doses of buprenorphine plus detomidine injected epidurally produced analgesia similar in intensity and duration to that of morphine plus detomidine injected epidurally.

Development of a risk stratification model for predicting acute renal failure in orthotopic liver transplantation recipients*

The purpose of this prospective observation cohort study was to develop and validate a risk stratification model for prediction of acute renal failure after liver transplantation. Data from 71 orthotopic liver transplantation recipients were used to develop a risk stratification model by binary logistic regression analysis containing the following variables: pretransplant hepatitis B and/or C infection; arterial hypertension; intra-operative mean arterial blood pressure before induction of anaesthesia; units of packed red blood cells required; hypotension (mean arterial blood pressure <or=50 mmHg); and maximum lactate concentration. Validation of the model on 167 consecutive patients revealed a sensitivity of 0.78, a specifity of 0.92, a negative predictive value of 0.96 and a positive predictive value of 0.62. This risk stratification model enables identification of orthotopic liver transplantation recipients with no or low risk for acute renal failure directly at the end of the transplantation procedure.

General anaesthesia for the cocaine abusing patient. Is it safe?

Commonly, cocaine abusing patient are scheduled for elective surgery with a positive urine test for cocaine metabolites. As many of these patients were clinically non-toxic [normal arterial pressure and heart rate, normothermic, and a normal (or unchanged from previous) ECG, including a QTc interval <500 ms], we have recently proceeded with elective surgery requiring general anaesthesia in this patient group. Forty urine cocaine positive patients were compared with an equal number of drug-free controls in a prospective, non-randomized, blinded analysis. Intraoperative mean arterial blood pressure, ST segment analysis, heart rate and body temperature were recorded and compared. Cardiovascular stability during and after general anaesthesia in cocaine positive, non-toxic patients was not significantly different when compared with an age and ASA matched drug-free control group. These results demonstrate that the non-toxic cocaine abusing patient can be administered general anaesthesia with no greater risk than comparable age and ASA matched drug-free patients.

Ischemic optic neuropathy following spine surgery

Visual loss after monocular surgery is rare, but devastating. The most common cause of perioperative visual loss (POVL) is ischemic optic neuropathy (ION). Increasing numbers of cases of ION are being reported after spine surgery, but the etiology of postoperative ION remains poorly understood. The growing concern about POVL has led neuroanesthesiologists to establish the ASA Postoperative Visual Loss Registry. This article summarized our current knowledge on this topic. The authors reviewed the literature and selected case reports of ION, specifically those reported after spine surgery performed with the patient in the prone position. Most of the cases involved posterior ION (PION, n = 17), and the remainder anterior (AION, n = 5). Most patients had no or few preoperative vascular disease risk factors. All except one PION and 2 of 5 AION cases reported symptom onset within the first 24 hours after surgery. Visual loss was frequently bilateral (40% of AION, 47% of PION cases). Mean operative time exceeded 450 minutes. The lowest average intraoperative mean arterial blood pressure was 64 mm Hg and the mean lowest intraoperative hematocrit was 27%. The average blood loss was 1.7 L for AION and 5 L for PION patients. PION patients received an average of 8 L of crystalloid solution and 2.2 L of colloid intraoperatively. This compilation of case reports suggests that a combination of prolonged surgery in the prone position, decreased ocular perfusion pressure, blood loss and anemia/hemodilution, and infusion of large quantities of intravenous fluids are some of the potential factors involved in the etiology of postoperative ION. However, levels of blood pressure and anemia intraoperatively were frequently at levels considered acceptable in anesthesia practice. The etiology of postoperative ION remains incompletely understood. Potential strategies to avoid this complication are discussed. —Valérie Biousse. Visual loss after monocular surgery is rare, but devastating. The most common cause of perioperative visual loss (POVL) is ischemic optic neuropathy (ION). Increasing numbers of cases of ION are being reported after spine surgery, but the etiology of postoperative ION remains poorly understood. The growing concern about POVL has led neuroanesthesiologists to establish the ASA Postoperative Visual Loss Registry. This article summarized our current knowledge on this topic. The authors reviewed the literature and selected case reports of ION, specifically those reported after spine surgery performed with the patient in the prone position. Most of the cases involved posterior ION (PION, n = 17), and the remainder anterior (AION, n = 5). Most patients had no or few preoperative vascular disease risk factors. All except one PION and 2 of 5 AION cases reported symptom onset within the first 24 hours after surgery. Visual loss was frequently bilateral (40% of AION, 47% of PION cases). Mean operative time exceeded 450 minutes. The lowest average intraoperative mean arterial blood pressure was 64 mm Hg and the mean lowest intraoperative hematocrit was 27%. The average blood loss was 1.7 L for AION and 5 L for PION patients. PION patients received an average of 8 L of crystalloid solution and 2.2 L of colloid intraoperatively. This compilation of case reports suggests that a combination of prolonged surgery in the prone position, decreased ocular perfusion pressure, blood loss and anemia/hemodilution, and infusion of large quantities of intravenous fluids are some of the potential factors involved in the etiology of postoperative ION. However, levels of blood pressure and anemia intraoperatively were frequently at levels considered acceptable in anesthesia practice. The etiology of postoperative ION remains incompletely understood. Potential strategies to avoid this complication are discussed. —Valérie Biousse.

Hypotensive epidural anesthesia in total knee replacement without tourniquet: Reduced blood loss and transfusion

Background and Objectives: For decades, hypotensive anesthesia has been used in an attempt to reduce intraoperative blood loss. Hypotensive epidural anesthesia (HEA) is a relatively new technique in hypotensive anesthesia. Use of a tourniquet has been shown to be associated with a higher risk of cardiovascular and thromboembolic complications. The effect of HEA on blood loss and need for transfusion in total knee replacement (TKR) is not known. Methods: Thirty consecutive patients scheduled for TKR were randomized to HEA without tourniquet or spinal anesthesia with the use of a tourniquet (SPI). HEA was performed as an epidurally induced sympathetic block and there was an infusion of low-dose epinephrine to stabilize the circulation. Results: Intraoperative mean arterial blood pressure was 48 mm Hg (HEA) versus 83 mm Hg (SPI) ( P < .001). Intraoperative blood loss was 146 mL (HEA) versus 13 mL (SPI) ( P < .001). Postoperative blood loss at any time was significantly reduced in the HEA group, and total loss of blood was 1,056 mL (HEA) versus 1,826 mL (SPI) ( P < .001). Half of the bleeding took place during the first 3 postoperative hours and 80% during the first 24 hours. In the HEA group, 57% of the patients went through surgery and the hospital stay without receiving blood transfusion versus 19% in the SPI group ( P < .05). There was a significantly reduced amount of blood transfusion in the HEA group (193 mL) versus 775 mL in the SPI group ( P < .005). No cardiopulmonary, cerebral, or renal complications were registered. Conclusions: We conclude that HEA is a safe technique that allows TKR without a tourniquet. Compared with spinal anesthesia, the use of HEA for TKR significantly reduces blood loss and the need for blood transfusion. Reg Anesth Pain Med 2001;26:105-110.

Propofol for maintenance of general anesthesia: A technique to limit blood loss during endoscopic sinus surgery

Purpose: Most cases of endoscopic sinus surgery are amenable to techniques using local anesthesia with monitored sedation. However, it is frequently the preference of the patient to have surgery under general anesthesia. One major drawback of general anesthesia is the increased bleeding encountered which can interfere with optimal visualization of the intranasal anatomy. In this study, an analysis was made to see if technique of general anesthesia has an impact on estimated blood loss in patients undergoing endoscopic sinus surgery. Methods: Twenty-five patients undergoing outpatient endoscopic sinus surgery under general anesthesia over a 1-year period were reviewed retrospectively to determine if anesthetic technique had an impact on estimated blood loss. Twelve patients were identified who received a continuous intravenous infusion of the nonbarbituate hypnotic agent propofol as the primary anesthetic agent, and 13 patients were identified who received anesthesia based on inhalational isoflurane. Results: There was no difference between the duration of surgery or the intraoperative mean arterial blood pressure when comparing the two groups. The average estimated blood loss in the propofol group was 101 mL compared with an average estimated blood loss of 251 mL in the isoflurane group ( P < .01). Conclusions: General anesthesia based on propofol infusion may have the advantage of decreased bleeding compared with conventional inhalation agents, making endoscopic sinus surgery technically easier and safer by improving endoscopic visualization of the surgical field. This anesthetic technique may have other applications in otolaryngology, where bleeding within a confined space frequently can interfere with visibility.