Preoperative Mean Arterial Blood Pressure Research Articles

The association between pre-operative variables, including blood pressure, and postoperative kidney function.

We used multivariate analyses to assess the association of pre-operative variables with kidney function in 41,523 adults after scheduled surgery in a single large academic hospital. Eight variables were independently associated with a reduction in postoperative estimated glomerular filtration rate: pre-operative renal function; age; ASA physical status; cardiac failure; anaemia; cancer; type of surgery; and the lowest quartile of pre-operative mean arterial blood pressure (< 71 mmHg). The estimated glomerular filtration rate fell by a mean (95% CI) of 2.7 (0.04-5.40) ml.min-1 .1.73 m-2 for patients with a pre-operative mean arterial pressure < 71 mmHg, p = 0.047. The same variables and male sex were associated with postoperative acute kidney injury. The odds ratio (95% CI) for acute postoperative kidney injury was 1.9 (1.2-2.9) for patients with a pre-operative mean arterial blood pressure < 71 mmHg, p = 0.005.

Controlled hypotensive anesthesia for functional endoscopic sinus surgery: a new protocol for dexmedetomidine administration

Objective The aim of the study was to conduct a comparative investigation to evaluate the efficacy of dexmedetomidine as a hypotensive agent by presenting a new protocol for administration versus the conventional protocol in functional endoscopic sinus surgery (FESS). Materials and methods Forty patients of ASA grade I-II scheduled for FESS were equally randomly assigned to two groups: the DEX group and the DEXnew group. The DEX group received dexmedetomidine at 1 μg/kg diluted in 10 ml normal saline 10 min before surgical incision (SI), followed by intravenous infusion of dexmedetomidine at 0.2-0.7 μg/kg/h according to the hemodynamic status and BIS. The DEXnew group received dexmedetomidine at 1 μg/kg diluted in 10 ml normal saline 10 min before SI, followed by intravenous top-up doses of 1/4 of the loading dose over 2 min in the form of intravenous shots to maintain MAP between 65 and 70 mmHg. Mean arterial blood pressure (MAP), heart rate (HR), cortisol level, fentanyl consumption, emergence time, and recovery from anesthesia (modified Aldrete score) were recorded. The sedation score and time to first analgesic request were recorded. Results In the DEX group there was a statistically significant decrease in MAP at 30, 45, 60, and 90 min after SI in comparison with preoperative MAP. In the DEXnew group also there was a statistically significant decrease in MAP at 30, 45, 60, and 90 min after SI in comparison with preoperative MAP. There was a nonsignificant difference as regards intraoperative fentanyl and postoperative pethidine consumption between the two groups. There was a significant decrease in the total amount of consumed dexmedetomidine in the DEXnew group (118 ± 14.6 μg) compared with the DEX group (189.4 ± 22.7 μg). Emergence time was significantly shorter in the DEXnew group (5.34±1.83 min) compared with the DEX group (9.45 ± 2.02 min). Conclusion This modified protocol of dexmedetomidine administration is safe and effective for controlled hypotension, providing an ideal surgical field during FESS. Compared with the conventional protocol of dexmedetomidine administration, the modified protocol offers fewer side effects; significant decrease in dexmedetomidine consumption, faster emergence time, and better modified Aldrete scores.

Does impotence improve after parathyroidectomy in men with primary hyperparathyroidism?

Erectile dysfunction (ED) is a common diagnosis associated with age, hypertension, cardiovascular disease, and diabetes. Primary hyperparathyroidism (PHP) is also seen with these comorbidities, but its association with ED has yet to be studied. We evaluated the rate and resolution of impotence after curative surgery for PHP. Prospectively collected data, including a self-reported questionnaire of symptoms, were reviewed for men who had curative parathyroid exploration for sporadic PHP from July 2010 to January 2014. Data were compared with an age-matched cohort of men who had thyroidectomy during the same period. Among 160 men with PHP and mean age of 60 years (range, 19-88), preoperative ED was reported by 13%, and this group was older than patients without ED (mean age, 70 vs 58 years, P < .01). Self-reported resolution of ED after parathyroidectomy occurred in 67% compared with 43% of patients in a thyroidectomy cohort. Preoperative mean arterial blood pressure was less in men with postoperative resolution of ED (96.6 vs 105.4 mm Hg, P = .03). Among 3 of 21 men on specific ED medications, 2 no longer required them postoperatively. Impotence is reported often by men undergoing parathyroidectomy for PHP. After curative surgery, 67% of those affected may self-report ED resolution, which may be more pronounced in those patients with a lesser preoperative mean arterial blood pressure.

Predicting the Limits of Cerebral Autoregulation During Cardiopulmonary Bypass

Mean arterial blood pressure (MAP) targets are empirically chosen during cardiopulmonary bypass (CPB). We have previously shown that near-infrared spectroscopy (NIRS) can be used clinically for monitoring cerebral blood flow autoregulation. The hypothesis of this study was that real-time autoregulation monitoring using NIRS-based methods is more accurate for delineating the MAP at the lower limit of autoregulation (LLA) during CPB than empiric determinations based on age, preoperative history, and preoperative blood pressure. Two hundred thirty-two patients undergoing coronary artery bypass graft and/or valve surgery with CPB underwent transcranial Doppler monitoring of the middle cerebral arteries and NIRS monitoring. A continuous, moving Pearson correlation coefficient was calculated between MAP and cerebral blood flow velocity and between MAP and NIRS data to generate mean velocity index and cerebral oximeter index. When autoregulated, there is no correlation between cerebral blood flow and MAP (i.e., mean velocity and cerebral oximetry indices approach 0); when MAP is below the LLA, mean velocity and cerebral oximetry indices approach 1. The LLA was defined as the MAP at which mean velocity index increased with declining MAP to ≥ 0.4. Linear regression was performed to assess the relation between preoperative systolic blood pressure, MAP, MAP in 10% decrements from baseline, and average cerebral oximetry index with MAP at the LLA. The MAP at the LLA was 66 mm Hg (95% prediction interval, 43 to 90 mm Hg) for the 225 patients in which this limit was observed. There was no relationship between preoperative MAP and the LLA (P = 0.829) after adjusting for age, gender, prior stroke, diabetes, and hypertension, but a cerebral oximetry index value of >0.5 was associated with the LLA (P = 0.022). The LLA could be identified with cerebral oximetry index in 219 (94.4%) patients. The mean difference in the LLA for mean velocity index versus cerebral oximetry index was -0.2 ± 10.2 mm Hg (95% CI, -1.5 to 1.2 mm Hg). Preoperative systolic blood pressure was associated with a higher LLA (P = 0.046) but only for those with systolic blood pressure ≤ 160 mm Hg. There is a wide range of MAP at the LLA in patients during CPB, making estimation of this target difficult. Real-time monitoring of autoregulation with cerebral oximetry index may provide a more rational means for individualizing MAP during CPB.

Ischemic Complications Occurring in the Contralateral Hemisphere after Surgical Treatment of Adults with Moyamoya Disease

Direct revascularization surgery is regarded as the most effective method of treatment of adults with moyamoya disease. These patients, however, have a higher risk of perioperative ischemic complications than do patients with atherosclerotic stroke, and are at risk for ischemic complications in the hemisphere contralateral to the one operated on. We investigated the incidence and risk factors for ischemic stroke in the contralateral hemisphere after surgical treatment of adults with moyamoya disease. We retrospectively reviewed the medical records and results of neuroimaging studies on 79 hemispheres of 73 consecutive patients with adult moyamoya disease (mean±SD age, 37.96±11.27 years; range, 18-62 years) who underwent direct bypass surgery over 6 years. Ischemic complications occurred in 4 of 79 (5.1%) contralateral hemispheres, one with Suzuki stage 3 and three with Suzuki stage 4. Three patients showed posterior cerebral artery (PCA) involvement by moyamoya vessels. Advanced stage of moyamoya disease (Suzuki stages 4/5/6; p=0.001), PCA involvement (p=0.001) and postoperative hypotension (mean arterial blood pressure <80% of preoperative mean arterial blood pressure) on the first (p<0.0001) and second (p=0.003) days after surgery were significantly correlated with postoperative contralateral ischemic complications. In patients with advanced moyamoya disease and involvement of the PCA, intentional hypotension can result in ischemic stroke in the hemisphere contralateral to the one operated on. Careful control of perioperative blood pressure is crucial for good surgical results.

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.

Trigeminocardiac Reflex

Object Surgical manipulation of the fifth cranial nerve during its intra-or extracranial course may lead to bradycardia or even asystole as well as arterial hypotension, a phenomenon described as the trigeminocardiac reflex (TCR). The authors studied the impact of this reflex on postoperative auditory function in patients undergoing vestibular schwannoma (VS) surgery. Methods One hundred patients scheduled for VS surgery were studied prospectively for parameters influencing the postoperative auditory function. The evaluation included sex, age, pre-and postoperative auditory function, preoperative mean arterial blood pressure, preoperative medical diseases or medication (for example, antiarrhythmia drugs), tumor size and localization, and the intraoperative occurrence of the TCR. The TCR, which occurred in 11% of the patients, influenced the postoperative hearing function in the patients with Hannover Class T3 and T4 VSs. With an overall hearing preservation of 47%, 11.1% of the patients in the TCR group and 51.4% of those in the non-TCR group experienced preserved hearing function postoperatively. In cases involving larger tumors (Hannover Class T3 and T4), an intraoperative TCR was associated with a significantly worse postoperative hearing function during VS surgery (p = 0.005). Conclusions The hypotension following TCR is a negative prognostic factor for hearing preservation in patients undergoing VS surgery. Patients' knowledge of this can be increased pre-and postoperatively. Further study of this phenomenon will advance the understanding of the underlying mechanisms and may help to improve hearing preservation by controlling the occurrence of the TCR.

Postoperative Pain Significantly Influences Postoperative Blood Loss in Patients Undergoing Total Knee Replacement

Although hypertension has long been recognized as a factor that might increase intraoperative blood losses in major orthopedic surgery, the effects of postoperative pain-induced hypertension on blood losses have not so far been evaluated. The aim of this study was to evaluate the effect of pain on perioperative blood losses of patients undergoing primary total knee replacement (TKR). Data from patients participating in a randomized clinical trial comparing intravenous patient-controlled analgesia (PCA) (N = 20) with PCA plus continuous femoral nerve (three-in-one) block (N = 20) or PCA plus continuous posterior lumbar plexus (psoas compartment) block (N = 20) were prospectively and retrospectively collected. Correlations between relevant variables and measured and calculated blood loss, number of transfused unit, and late (96 hours) postoperative hemoglobin were tested by linear regressions. Stepwise regressions for each of the four above-mentioned goals were constructed using a probability to enter of 0.25 and to leave of 0.1. A P < 0.05 was considered significant. At the stepwise regressions there was a significant positive correlation between measured blood losses and morphine consumption from 12 to 18 hours (P = 0.006); between calculated blood loss and preoperative mean arterial blood pressure (P = 0.01) and preoperative hemoglobin value (P = 0.02); and between late postoperative hemoglobin and body weight (P = 0.047). In patients undergoing TKR, there is a significant correlation between measured blood loss and morphine consumption from 12 to 18 hours. It is concluded that postoperative pain significantly influences postoperative blood loss in patients undergoing TKR.

The impact of hypotension due to the trigeminocardiac reflex on auditory function in vestibular schwannoma surgery

Surgical manipulation of the fifth cranial nerve during its intra- or extracranial course may lead to bradycardia or even asystole as well as arterial hypotension, a phenomenon described as the trigeminocardiac reflex (TCR). The authors studied the impact of this reflex on postoperative auditory function in patients undergoing vestibular schwannoma (VS) surgery. One hundred patients scheduled for VS surgery were studied prospectively for parameters influencing the postoperative auditory function. The evaluation included sex, age, pre- and postoperative auditory function, preoperative mean arterial blood pressure, preoperative medical diseases or medication (for example, antiarrhythmia drugs), tumor size and localization, and the intraoperative occurrence of the TCR. The TCR, which occurred in 11% of the patients, influenced the postoperative hearing function in the patients with Hannover Class T3 and T4 VSs. With an overall hearing preservation of 47%, 11.1% of the patients in the TCR group and 51.4% of those in the non-TCR group experienced preserved hearing function postoperatively. In cases involving larger tumors (Hannover Class T3 and T4), an intraoperative TCR was associated with a significantly worse postoperative hearing function during VS surgery (p = 0.005). The hypotension following TCR is a negative prognostic factor for hearing preservation in patients undergoing VS surgery. Patients' knowledge of this can be increased pre- and postoperatively. Further study of this phenomenon will advance the understanding of the underlying mechanisms and may help to improve hearing preservation by controlling the occurrence of the TCR.

Liver hemorrhage during laparotomy in patients with necrotizing enterocolitis

Major liver hemorrhage (LH) without obvious iatrogenic injury was recently observed in several patients during operation for necrotizing enterocolitis (NEC). The purpose of this study was to determine the incidence and risk factors associated with the development of LH in patients with NEC. Methods: The hospital charts of patients with NEC who underwent surgical exploration during a 5-year period (1989–1994) were reviewed. The patients in whom LH developed without obvious significant iatrogenic liver injury were compared with those who did not have LH. Results: Eight of the 68 patients reviewed had LH. The survival rate for those with LH was 13%, compared with 88% for those without LH (P < .001). The patients with LH had a younger gestational age (28 ± 3 weeks v 32 ± 5 weeks) and a lower birth weight (1,262 ± 489 g v 1,649 ± 686 g); however, the differences were not significant. The patients with LH had significantly lower preoperative mean arterial blood pressure (35 ± 1mm Hg v 46 ± 3mm Hg; P < .001) and required greater fluid intake (272 ± 28mL/kg/d v 186 ± 9 mL/kg/d; P < .01) for the 24 hours preceding surgery. Conclusion: LH is as an important and lethal complication associated with laparotomy in very small infants with NEC. The presence of hypotension and the administration of large amounts of volume in the preoperative period appear to be risk factors. Earlier surgical intervention and restoration of blood pressure using inotropic agents, once a particular level of fluid administration has been achieved, my be preventive.