- Email: [email protected]
Cerebral oxygenation in the beach chair position before and during general anesthesia in patients with and without cardiovascular risk factors
Journal of Clinical Anesthesia (2015) xx, xxx–xxx
Original contribution
Cerebral oxygenation in the beach chair position before and during general anesthesia in patients with and without cardiovascular risk factors☆ Yukiko Mori MD (Staff Anesthesiologist) a , Masana Yamada MD, PhD (Staff Anesthesiologist) b , Takahiko Akahori MD (Staff Anesthesiologist) a , Noboru Hatakeyama MD, PhD (Professor) c , Mitsuaki Yamazaki MD, PhD (Professor)d , Yoshihiro Fujiwara MD, PhD (Professor)c , Hiroyuki Kinoshita MD, PhD (Professor)c,⁎ a
Department of Anesthesiology, Aichi Medical University School of Medicine, 1-1 Yazako Karimata, Nagakute 480-1195, Japan Department of Anesthesiology, Toyama University School of Medicine, 2630 Sugitani, Toyama 930-0194, Japan c Department of Anesthesiology, Aichi Medical University School of Medicine, 1-1 Yazako Karimata, Nagakute 480-1195, Japan d Department of Anesthesiology, Toyama University School of Medicine, 2630 Sugitani, Toyama 930-0194, Japan b
Received 18 August 2014; revised 20 April 2015; accepted 4 June 2015
Keywords: Beach chair position; Cerebral oxygenation; General anesthesia; Near-infrared spectroscopy; Tissue oxygen index
Abstract Study ObjectivesTo evaluate changes in cerebral tissue oxygen index (TOI) values under the beach chair position before and during general anesthesia in surgical patients with or without cardiovascular risk factors. Design: Prospective study. Setting: Operating room in the university hospital. Patients: Ninety-one patients undergoing surgery, including healthy patients (n = 28), patients with 1 cardiovascular risk factor (n = 33), and those with more than 1 risk factor (n = 30). Interventions and Measurements: Cerebral TOI the day before and during general anesthesia was evaluated using a near-infrared spectroscopy NIRO-200 (Hamamatsu Photonics, Hamamatsu, Japan) for each patient. The initial TOI measurement in the supine position after a 10-minute rest or 10 minute after the endotracheal intubation was followed by measurements in 30° and subsequent 60° upright position for 5 minutes. Phenylephrine 0.1 mg and/or ephedrine 4 mg was administered intravenously to maintain mean blood pressure above 60 mm Hg accordingly. Main Results: The beach chair position decreased mean arterial blood pressure and heart rate under general anesthesia, although patients with more than 1 cardiovascular risk factor needed significantly more phenylephrine doses to maintain mean blood pressure above 60 mm Hg. Values of TOI were within the normal range of about 70% before and during anesthesia in all groups.
☆
Disclosure: This work was presented in part at the annual meeting of the American Society of Anesthesiologists; Chicago, IL; October 15-19, 2011. This work was supported by departmental sources, and there is no conflict of interest regarding this study. ⁎ Corresponding author at: Department of Anesthesiology, Aichi Medical University, School of Medicine, 1-1 Yazako Karimata, Nagakute 480-1195, Japan. Tel.: + 81 561 62 3311; fax: +81 561 63 6621. E-mail address: [email protected] (H. Kinoshita). http://dx.doi.org/10.1016/j.jclinane.2015.06.007 0952-8180/© 2015 Elsevier Inc. All rights reserved.
2
Y. Mori et al. Conclusions: The beach chair position under general anesthesia did not alter cerebral oxygenation in patients with or without cardiovascular risk factors showing normal preoperative cerebral TOI values when the mean blood pressure was maintained above 60 mm Hg. The careful management using the cerebral oxygenation monitoring appears to maintain cerebral perfusion in the beach chair position during general anesthesia. © 2015 Elsevier Inc. All rights reserved.
1. Introduction The beach chair position reportedly provides good surgical condition for surgeons in arthroscopic shoulder surgery [1]. However, a possible decrease in cerebral oxygenation related to this position has been suggested by many previous reports, although exact mechanisms of the catastrophic complication remain to be determined [2–4]. Near-infrared spectroscopy is one of the methodologies for noninvasive and continuous evaluation of cerebral oxygenation, which reflects the balance between cerebral metabolic supply and demand [5]. Near-infrared spectroscopy demonstrates similar accuracy regarding the detection of cerebral ischemia to transcranial Doppler sonography or stump pressure measurements [6]. More importantly, the cerebral tissue oxygen index (TOI) is probably most reliable in parameters derived from cerebral near-infrared spectroscopy because the tissue hemoglobin concentration, skull thickness, and the area of the cerebrospinal fluid layer do not affect TOI values [7]. Our previous study demonstrated that the beach chair position under general anesthesia did not alter cerebral TOI values in patients showing normal preoperative TOI values, whereas this preliminary study did not determine differences of cerebral TOI values between patients with and without cardiovascular risk factors [8]. The combination of cardiovascular risk factors is likely to aggravate the cerebrovascular disease outcome because previous studies demonstrated that each cardiovascular risk factor including hypertension and diabetes mellitus independently contributes to the prevalence of intracranial atherosclerosis and/or brain infarction [9,10]. Therefore, the current study was designed to evaluate changes in cerebral TOI values under the beach chair position before and during general anesthesia in surgical patients with or without cardiovascular risk factors and to examine whether maintenance of mean blood pressure above 60 mm Hg affords appropriate cerebral TOI values under the beach chair position in the population.
2. Materials and methods After institutional approval, informed consent was obtained from patients undergoing shoulder surgery. Ninety-one patients undergoing shoulder surgery were assigned to the patients without any cardiovascular risk factor (healthy group, n = 28), patients with 1 cardiovascular
risk factor (risk factor 1 group, n = 33), and those with more than 1 risk factor (risk factor 2 group, n = 30). Cardiovascular risk factors in this study contained cardiac diseases including angina pectoris and valvular disease, diabetes mellitus, hypertension, hypercholesterolemia, and smoking. Patients with the history of syncope and/or redness or rash on their forehead were excluded from this study.
2.1. Near-infrared spectroscopy measurement Cerebral TOI (%) was evaluated using NIRO-200 (Hamamatsu Photonics, Hamamatsu, Japan) with 3 wavelengths of near-infrared light (775, 810, and 850 nm), and the sensor contains a laser diode and 2 detectors placed at 3.7 and 4.3 cm from the source of emitting light [8]. The oximeter probes were put on the bilateral forehead with the caudal border 1 cm above the eyelash for the measurement of the left and right TOI, respectively [8].
2.2. Protocol of measurements During the measurements, noninvasive blood pressure in the upper limb at the heart level in 1-minute intervals and continuous heart rate by the electrocardiogram in addition to pulse oximetry was monitored [8]. Support stockings were placed on enrolled patients' lower extremities. Twenty-four hours before the induction of general anesthesia, the initial cerebral TOI measurement after 10-minute rest in the supine position was followed by measurements in 30° and subsequent 60° head-up tilt positions for 5 minutes [8]. Hemodynamic changes in response to the 90° head-up tilt under general anesthesia with volatile anesthetics were reportedly stable beyond 5 minutes after the positioning [11,12]. Therefore, the current study determined cerebral TOI as well as cardiovascular parameters 5 minutes after the 30° and subsequent 60° head-up tilt positions. The current study defined abnormal TOI as below 60% at any point [13], but no patient who enrolled in this study showed preoperative abnormal cerebral TOI values. On the day of surgery, patients were allowed to take clear fluids freely until 6 hours before the induction of anesthesia. After arrival in the operating room, acetate Ringer's solution was administered at a rate of 10 mL kg− 1 h− 1 throughout the study period. After application of monitors and preoxygenation, anesthesia was induced with propofol 1.5 mg/kg intravenously (IV), followed by vecuronium 0.1 mg/kg IV. After bag-mask ventilation with a facemask using 3%
Cerebral oxygenation in the beach chair position sevoflurane in 100% oxygen at a fresh gas flow of 6 L/min for 3 minutes, the patient's trachea was intubated with a reinforced endotracheal tube. After the intubation, patients were mechanically ventilated as normocapnia (end-tidal carbon dioxide tension = 35-40 mm Hg) under inhalation of 1.5% sevoflurane in 50% oxygen. Ten minutes after the tracheal intubation, the initial TOI measurement in the supine position was followed by measurements in 30° and subsequent 60° head-up tilt positions for 5 minutes. Mean blood pressure less than 60 mm Hg was treated with 0.1 mg phenylephrine and/or 4 mg ephedrine IV.
2.3. Statistical methods The data were expressed as mean ± SD. The power calculation was done using Sample Power 3.0 (IBM Japan Inc, Tokyo, Japan) with a decrease in cerebral TOI values more than 8, which is equivalent to 13% decrease from the cerebral TOI limit of 60%, in response to the beach chair position during anesthesia as the primary end point [13,14]. In the current study, a sample size of 17 gave 80% power to the detected TOI change of 10% at a significance level of .05 (SD = 10). Statistical analysis using PASW Statistics 18 (IBM Japan Inc) was performed by the χ 2 test or repeated-measures analysis of variance followed by Scheffe test. Differences were considered to be statistically significant when the P value is less than .05.
3. Results Table 1 shows clinical and procedural characteristics of the study population. Patients in the risk factor 2 group were significantly older than those in other groups (Table 1). Risk factor 1 or 2 group involved more patients with hypertension, hypercholesterolemia and current smoking, and cardiac disease, diabetes, hypertension, hypercholesterolemia, and current smoking compared with the healthy group, respectively (Table 1). Preoperative mean blood pressure and heart rate, however, did not differ among groups (Fig. 1). Without Table 1
3 general anesthesia, the beach chair position with the 60° head-up tilt did not affect the mean blood pressure as well as heart rate (Fig. 1). Mean blood pressure under general anesthesia was significantly less than that before anesthesia in all groups (Fig. 1). However, the beach chair position did not further alter this reduction (Fig. 1). General anesthesia gave the tendency of decrease in heart rate whereas the head-up tilt itself mostly did not result in further heart rate changes, although it produced little differences at the 60° head-up tilt (Fig. 1). The mean phenylephrine dose to treat hypotension during general anesthesia with beach chair position was significantly more in the risk factor 2 group than in other groups (Table 2). All patients demonstrated normal preoperative baseline cerebral TOI values, and they did not show any abnormal cerebral TOI values in response to the beach chair position before anesthesia (Fig. 2). Irrespective of decreases in both blood pressure and heart rate, the beach chair position under general anesthesia did not alter the TOI values about 70% throughout the measurements (Fig. 2). No patient in this study documented adverse postoperative outcome.
4. Discussion The beach chair position with the 60° head-up tilt without anesthesia did not alter the mean blood pressure as well as heart rate in all studied groups. These results suggest that patients with and without cardiovascular risk factors in the current study preserved the physiological hemodynamic responses to head-up postures [15]. In all groups, general anesthesia gave the tendency of a decrease in the mean blood pressure and heart rate, whereas the head-up tilt itself basically did not result in further hemodynamic changes. The phenylephrine dose during general anesthesia with beach chair position was significantly larger in the risk factor 2 group than in other groups. Administration of vasoactive substances including phenylephrine to maintain mean blood pressure above 60 mm Hg should play a role in the stable hemodynamics during anesthesia irrespectively with the 60°
Demographic data of enrolled patients
Age (y), mean ± SD Sex (M/F) BMI (kg/m2), mean ± SD Hb (g/dL), mean ± SD Cardiac diseases (n) Diabetes mellitus (n) Hypertension (n) Hypercholesterolemia (n) Current smoking (n)
Healthy group (n = 28)
Risk factor 1 group (n = 33)
Risk factor 2 group (n = 30)
55 ± 16 18/10 23.2 ± 2.1 13.8 ± 1.5 0 0 0 0 0
59 ± 14 20/13 24.7 ± 4.4 13.9 ± 1.9 1 5 9⁎ 10 ⁎ 9⁎
65 ± 10 ⁎ 20/10 24.4 ± 2.6 13.6 ± 1.6 7⁎ 14 ⁎ 22 ⁎ 21 ⁎ 10 ⁎
Risk factor 1 group: patients with 1 risk factor; risk factor 2 group: patients with more than 1 risk factor. ⁎ P b .05 vs healthy group.
4
Y. Mori et al.
Fig. 1 Changes in mean blood pressure (left) and heart rate (right) according to 30° to 60° head-up tilt positions before and during general anesthesia. Values were significantly reduced compared with those before anesthesia. *P b .05.
head-up tilt. The α-adrenergic receptor activation induced by phenylephrine, at least partly, may also add some effects of reactive decrease in heart rate. Collectively, it might be concluded that general anesthesia using sevoflurane in combination with some vasoactive agents including phenylephrine may modulate hemodynamic changes according to the beach chair position. Indeed, a recent study has documented that sevoflurane-nitrous oxide, but not propofol-remifentanil, anesthesia affords an advantage to stabilize the mean blood pressure in the beach chair position [3]. Irrespective of decreases in both blood pressure and heart rate, the beach chair position under general anesthesia did not alter the cerebral TOI values throughout the current study. The beach chair position under general anesthesia with a careful blood pressure management that maintains mean Table 2 Phenylephrine and/or ephedrine requirement during measurements under general anesthesia in this study. Healthy group Risk factor 1 Risk factor 2 (n = 28) group (n = 33) group (n = 30) Phenylephrine 0.13 ± 0.20 (mg) Ephedrine 0.86 ± 3.33 (mg)
0.22 ± 0.38
0.48 ± 0.48 ⁎
0.73 ± 2.5
4.4 ± 9.00
Values are presented as means ± SD. ⁎ P b .05 vs healthy group.
blood pressure above 60 mm Hg probably does not alter cerebral oxygenation in patients with and without cardiovascular risk factors showing normal preoperative cerebral TOI values. The following factors may contribute to the desirable condition of cerebral oxygenation during the beach chair position in the current study. First, sevoflurane, compared with isoflurane, reportedly well preserves dynamic cerebral pressure autoregulation in humans [16]. Sevofluranenitrous oxide, but not propofol-remifentanil, anesthesia keeps up cerebral oxygen saturation measured by near-infrared spectroscopy as well as jugular venous bulb oxygen saturation in the beach chair position [3]. These results suggest that sevoflurane favors maintenance of cerebral oxygenation in the beach chair position. Second, previous studies indicated that the blood pressure management where it maintains mean blood pressure above 60 mm Hg, but not below this level, preserves cerebral oxygenation above the critical levels of 60% [17–19]. These results draw the conclusion that the mean blood pressure–oriented management during general anesthesia is necessary to avoid cerebral desaturation in the beach chair position. Indeed, Cullen and Kirby recommended treating blood pressure less than 80% of preoperative resting values during the beach chair position [20]. It is crucial for personnel involved in clinical anesthesia to remember the concept that some patients, who represent abnormal preoperative TOI values, may have much higher-than-expected lower limits of cerebral
Cerebral oxygenation in the beach chair position
Fig. 2
5
Changes in left and right cerebral TOIs (%) according to 30° to 60° head-up tilt positions before and during general anesthesia.
autoregulation [21]. Third, phenylephrine yields higher cerebral perfusion pressure in patients with traumatic brain injury compared with dopamine and norepinephrine, suggesting the desirable property of this vasoconstrictor agent in the cerebral circulation [22]. It is crucial to note that another vasoconstrictor agent vasopressin reduces cerebral oxygenation during the beach chair position despite the mean blood pressure elevation [4]. These results suggest that phenylephrine is probably one of the most valuable vasopressors, which are available in the clinical practice, to preserve cerebral oxygenation during anesthesia in the beach chair position. Clinicians should be cautious, however, because phenylephrine may cause a false-positive decrease in the near-infrared spectroscopy–determined cerebral oxygenation using INVOS by constricting extracranial vasculature [23]. Whether NIRO and INVOS similarly cause this phenomenon has been unclear, and further studies will require resolving the issue. The current study has several limitations to be evaluated and verified by future studies as follows. First, the blood pressure measurement might have to be done at the level of the head because the authors tried to show any changes of cerebral autoregulation according to the beach chair position in this study. However, using the measurement at the head level is not practical in the routine anesthetic management. In addition, the resistance to cerebral blood flow, but not the vertical distance above the heart, may solely determine cerebral perfusion pressure when one considers the siphon system [24,25]. In that occasion, the head elevation may not
decrease cerebral blood flow so long as mean arterial pressure at the level of the heart is not allowed to change, although this theory has not been proven in the beach chair position. Second, patients with more cardiovascular risk factors needed more vasopressors to maintain the mean blood pressure above the limitation of 60 mm Hg in the current study. We cannot rule out a possibility that this difference was due to the older study population in the risk factor 2 group. Third, the authors tried to evaluate changes in TOI values only for a short duration during anesthesia. Not only the positioning but also other conditions such as surgical bleeding or necessity for high-dose sevoflurane during anesthesia should affect the TOI values during surgery in the beach chair position. Fourth, the end-tidal carbon dioxide tension and sevoflurane concentration had to be set at the exactly same value during measurements in the anesthetic condition. In the current study, the beach chair position under general anesthesia did not alter cerebral oxygenation in patients with or without cardiovascular risk factors showing normal preoperative cerebral TOI values when the mean blood pressure was maintained above 60 mm Hg. It can be concluded that maintaining mean arterial blood pressure by vasopressors helps cerebral autoregulation and cerebral perfusion pressure in the beach chair position during general anesthesia as reflected by the minimal change in cerebral oxygenation monitoring. The authors would also emphasize the importance of preoperative cerebral TOI evaluation in these patients. The clinical implication of the current study,
6 however, has been still unclear because near-infrared spectroscopy detects a small area of the brain and cerebral ischemia is possible to occur in areas beyond the ability of this cerebral oxygen monitoring [7,26]. Further studies should determine the margin of safety in the anesthetic management with the beach chair position including the mean blood pressure limit to prevent cerebral desaturation.
References [1] Papadonikolakis A, Wiesler ER, Olympio MA, Poehling GG. Avoiding catastrophic complications of stroke and death related to shoulder surgery in the sitting position. Arthroscopy 2008;24:481-2. [2] Pohl A, Cullen DJ. Cerebral ischemia during shoulder surgery in the upright position: a case series. J Clin Anesth 2005;17:463-9. [3] Jeong H, Jeong S, Lim HJ, Lee J, Yoo KY. Cerebral oxygen saturation measured by near-infrared spectroscopy and jugular venous bulb oxygen saturation during arthroscopic shoulder surgery in beach chair position under sevoflurane-nitrous oxide or propofol-remifentanil anesthesia. Anesthesiology 2012;116:1047-56. [4] Cho SY, Kim SJ, Jeong CW, Jeong CY, Chung SS, Lee J, et al. Under general anesthesia arginine vasopressin prevents hypotension but impairs cerebral oxygenation during arthroscopic shoulder surgery in the beach chair position. Anesth Analg 2013;117:1436-43. [5] Smith M, Elwell C. Near-infrared spectroscopy: shedding light on the injured brain. Anesth Analg 2009;108:1055-7. [6] Moritz S, Kasprzak P, Arlt M, Taeger K, Metz C. Accuracy of cerebral monitoring in detecting cerebral ischemia during carotid endarterectomy: a comparison of transcranial Doppler sonography, near-infrared spectroscopy, stump pressure, and somatosensory evoked potentials. Anesthesiology 2007;107:563-9. [7] Yoshitani K, Kawaguchi M, Miura N, Okuno T, Kanoda T, Ohnishi Y, et al. Effects of hemoglobin concentration, skull thickness, and the area of the cerebrospinal fluid layer on near-infrared spectroscopy measurements. Anesthesiology 2007;106:458-62. [8] Tange K, Kinoshita H, Minonishi T, Hatakeyama N, Matsuda N, Yamazaki M, et al. Cerebral oxygenation in the beach chair position before and during general anesthesia. Minerva Anestesiol 2010;76: 485-9. [9] Fanning JP, Wong AA, Fraser JF. The epidemiology of silent brain infarction: a systematic review of population-based cohorts. BMC Med 2014;12:119.
Y. Mori et al. [10] Ritz K, Denswil NP, Stam OCG, Van Lieshout JJ, Daemen MJAP. Cause and mechanisms of intracranial atherosclerosis. Circulation 2014;130:1407-14. [11] Dalrymple DG, MacGowan SW, MacLeod GF. Cardiorespiratory effects of the sitting position in neurosurgery. Br J Anaesth 1979;51:1079-82. [12] Marshall WK, Bedford RF, Miller ED. Cardiovascular responses in the seated position: impact of four anesthetic techniques. Anesth Analg 1983;62:648-53. [13] Yoshitani K, Kawaguchi M, Tatsumi K, Kitaguchi K, Furuya H. A comparison of the INVOS 4100 and the NIRO 300 near-infrared spectroscopy. Anesth Analg 2002;94:586-90. [14] Al-Rawi PG, Kirkpatrick PJ. Tissue oxygen index: thresholds for cerebral ischemia using near-infrared spectroscopy. Stroke 2006;37:2720-5. [15] Smith JJ, Porth CM, Erickson M. Hemodynamic response to the upright posture. J Clin Pharmacol 1994;34:375-86. [16] Summors AC, Gupta AK, Matta BF. Dynamic cerebral autoregulation during sevoflurane anesthesia: a comparison with isoflurane. Anesth Analg 1999;88:341-5. [17] Murphy GS, Szokol JW, Marymont JH, Greenberg SB, Avram MJ, Vender JS, et al. Cerebral oxygen desaturation events assessed by nearinfrared spectroscopy during shoulder arthroscopy in the beach chair and lateral decubitus positions. Anesth Analg 2010;111:496-505. [18] Moerman AT, De Hert SG, Jacobs TF, De Wilde LF, Wouters PF. Cerebral oxygen desaturation during beach chair position. Eur J Anaesthesiol 2012;29:82-7. [19] Closhen D, Berres M, Werner C, Engelhard K, Schramm P. Influence of beach chair position on cerebral oxygen saturation: a comparison of INVOS and FORE-SIGHT cerebral oximeter. J Neurosurg Anesthesiol 2013;25:414-9. [20] Cullen DJ, Kirby RR. Beach chair position may decrease cerebral perfusion: catastrophic outcomes have occurred. APSF Newsl 2007;22:25-7. [21] Drummond JC. The lower limit of autoregulation: time to revise our thinking? Anesthesiology 1997;86:1431-3. [22] Sookplung P, Siriussawakul A, Malakouti A, Sharma D, Wang J, Souter MJ, et al. Vasopressor use and effect on blood pressure after severe adult traumatic brain injury. Neurocrit Care 2011;15:46-54. [23] Ogoh S, Sato K, Okazaki K, Miyamoto T, Secher F, Sørensen H, et al. A decrease in spatially resolved near-infrared spectroscopy-determined frontal lobe tissue oxygenation by phenylephrine reflects reduced skin blood flow. Anesth Analg 2014;118:823-9. [24] Hicks JW, Munis JR. The siphon controversy counterpoint: the brain need not be “baffling”. Am J Physiol 2005;289:R629-32. [25] Munis JR, Lozada LJ. Giraffes, siphons, and starling resistors: cerebral perfusion pressure revisited. J Neurosurg Anesthesiol 2000;12:290-6. [26] Quaresima V, Sacco S, Totaro R, Ferrari M. Noninvasive measurement of cerebral hemoglobin saturation using two near infrared spectroscopy approaches. J Biomed Opt 2000;5:201-5.
Original contribution
Cerebral oxygenation in the beach chair position before and during general anesthesia in patients with and without cardiovascular risk factors☆ Yukiko Mori MD (Staff Anesthesiologist) a , Masana Yamada MD, PhD (Staff Anesthesiologist) b , Takahiko Akahori MD (Staff Anesthesiologist) a , Noboru Hatakeyama MD, PhD (Professor) c , Mitsuaki Yamazaki MD, PhD (Professor)d , Yoshihiro Fujiwara MD, PhD (Professor)c , Hiroyuki Kinoshita MD, PhD (Professor)c,⁎ a
Department of Anesthesiology, Aichi Medical University School of Medicine, 1-1 Yazako Karimata, Nagakute 480-1195, Japan Department of Anesthesiology, Toyama University School of Medicine, 2630 Sugitani, Toyama 930-0194, Japan c Department of Anesthesiology, Aichi Medical University School of Medicine, 1-1 Yazako Karimata, Nagakute 480-1195, Japan d Department of Anesthesiology, Toyama University School of Medicine, 2630 Sugitani, Toyama 930-0194, Japan b
Received 18 August 2014; revised 20 April 2015; accepted 4 June 2015
Keywords: Beach chair position; Cerebral oxygenation; General anesthesia; Near-infrared spectroscopy; Tissue oxygen index
Abstract Study ObjectivesTo evaluate changes in cerebral tissue oxygen index (TOI) values under the beach chair position before and during general anesthesia in surgical patients with or without cardiovascular risk factors. Design: Prospective study. Setting: Operating room in the university hospital. Patients: Ninety-one patients undergoing surgery, including healthy patients (n = 28), patients with 1 cardiovascular risk factor (n = 33), and those with more than 1 risk factor (n = 30). Interventions and Measurements: Cerebral TOI the day before and during general anesthesia was evaluated using a near-infrared spectroscopy NIRO-200 (Hamamatsu Photonics, Hamamatsu, Japan) for each patient. The initial TOI measurement in the supine position after a 10-minute rest or 10 minute after the endotracheal intubation was followed by measurements in 30° and subsequent 60° upright position for 5 minutes. Phenylephrine 0.1 mg and/or ephedrine 4 mg was administered intravenously to maintain mean blood pressure above 60 mm Hg accordingly. Main Results: The beach chair position decreased mean arterial blood pressure and heart rate under general anesthesia, although patients with more than 1 cardiovascular risk factor needed significantly more phenylephrine doses to maintain mean blood pressure above 60 mm Hg. Values of TOI were within the normal range of about 70% before and during anesthesia in all groups.
☆
Disclosure: This work was presented in part at the annual meeting of the American Society of Anesthesiologists; Chicago, IL; October 15-19, 2011. This work was supported by departmental sources, and there is no conflict of interest regarding this study. ⁎ Corresponding author at: Department of Anesthesiology, Aichi Medical University, School of Medicine, 1-1 Yazako Karimata, Nagakute 480-1195, Japan. Tel.: + 81 561 62 3311; fax: +81 561 63 6621. E-mail address: [email protected] (H. Kinoshita). http://dx.doi.org/10.1016/j.jclinane.2015.06.007 0952-8180/© 2015 Elsevier Inc. All rights reserved.
2
Y. Mori et al. Conclusions: The beach chair position under general anesthesia did not alter cerebral oxygenation in patients with or without cardiovascular risk factors showing normal preoperative cerebral TOI values when the mean blood pressure was maintained above 60 mm Hg. The careful management using the cerebral oxygenation monitoring appears to maintain cerebral perfusion in the beach chair position during general anesthesia. © 2015 Elsevier Inc. All rights reserved.
1. Introduction The beach chair position reportedly provides good surgical condition for surgeons in arthroscopic shoulder surgery [1]. However, a possible decrease in cerebral oxygenation related to this position has been suggested by many previous reports, although exact mechanisms of the catastrophic complication remain to be determined [2–4]. Near-infrared spectroscopy is one of the methodologies for noninvasive and continuous evaluation of cerebral oxygenation, which reflects the balance between cerebral metabolic supply and demand [5]. Near-infrared spectroscopy demonstrates similar accuracy regarding the detection of cerebral ischemia to transcranial Doppler sonography or stump pressure measurements [6]. More importantly, the cerebral tissue oxygen index (TOI) is probably most reliable in parameters derived from cerebral near-infrared spectroscopy because the tissue hemoglobin concentration, skull thickness, and the area of the cerebrospinal fluid layer do not affect TOI values [7]. Our previous study demonstrated that the beach chair position under general anesthesia did not alter cerebral TOI values in patients showing normal preoperative TOI values, whereas this preliminary study did not determine differences of cerebral TOI values between patients with and without cardiovascular risk factors [8]. The combination of cardiovascular risk factors is likely to aggravate the cerebrovascular disease outcome because previous studies demonstrated that each cardiovascular risk factor including hypertension and diabetes mellitus independently contributes to the prevalence of intracranial atherosclerosis and/or brain infarction [9,10]. Therefore, the current study was designed to evaluate changes in cerebral TOI values under the beach chair position before and during general anesthesia in surgical patients with or without cardiovascular risk factors and to examine whether maintenance of mean blood pressure above 60 mm Hg affords appropriate cerebral TOI values under the beach chair position in the population.
2. Materials and methods After institutional approval, informed consent was obtained from patients undergoing shoulder surgery. Ninety-one patients undergoing shoulder surgery were assigned to the patients without any cardiovascular risk factor (healthy group, n = 28), patients with 1 cardiovascular
risk factor (risk factor 1 group, n = 33), and those with more than 1 risk factor (risk factor 2 group, n = 30). Cardiovascular risk factors in this study contained cardiac diseases including angina pectoris and valvular disease, diabetes mellitus, hypertension, hypercholesterolemia, and smoking. Patients with the history of syncope and/or redness or rash on their forehead were excluded from this study.
2.1. Near-infrared spectroscopy measurement Cerebral TOI (%) was evaluated using NIRO-200 (Hamamatsu Photonics, Hamamatsu, Japan) with 3 wavelengths of near-infrared light (775, 810, and 850 nm), and the sensor contains a laser diode and 2 detectors placed at 3.7 and 4.3 cm from the source of emitting light [8]. The oximeter probes were put on the bilateral forehead with the caudal border 1 cm above the eyelash for the measurement of the left and right TOI, respectively [8].
2.2. Protocol of measurements During the measurements, noninvasive blood pressure in the upper limb at the heart level in 1-minute intervals and continuous heart rate by the electrocardiogram in addition to pulse oximetry was monitored [8]. Support stockings were placed on enrolled patients' lower extremities. Twenty-four hours before the induction of general anesthesia, the initial cerebral TOI measurement after 10-minute rest in the supine position was followed by measurements in 30° and subsequent 60° head-up tilt positions for 5 minutes [8]. Hemodynamic changes in response to the 90° head-up tilt under general anesthesia with volatile anesthetics were reportedly stable beyond 5 minutes after the positioning [11,12]. Therefore, the current study determined cerebral TOI as well as cardiovascular parameters 5 minutes after the 30° and subsequent 60° head-up tilt positions. The current study defined abnormal TOI as below 60% at any point [13], but no patient who enrolled in this study showed preoperative abnormal cerebral TOI values. On the day of surgery, patients were allowed to take clear fluids freely until 6 hours before the induction of anesthesia. After arrival in the operating room, acetate Ringer's solution was administered at a rate of 10 mL kg− 1 h− 1 throughout the study period. After application of monitors and preoxygenation, anesthesia was induced with propofol 1.5 mg/kg intravenously (IV), followed by vecuronium 0.1 mg/kg IV. After bag-mask ventilation with a facemask using 3%
Cerebral oxygenation in the beach chair position sevoflurane in 100% oxygen at a fresh gas flow of 6 L/min for 3 minutes, the patient's trachea was intubated with a reinforced endotracheal tube. After the intubation, patients were mechanically ventilated as normocapnia (end-tidal carbon dioxide tension = 35-40 mm Hg) under inhalation of 1.5% sevoflurane in 50% oxygen. Ten minutes after the tracheal intubation, the initial TOI measurement in the supine position was followed by measurements in 30° and subsequent 60° head-up tilt positions for 5 minutes. Mean blood pressure less than 60 mm Hg was treated with 0.1 mg phenylephrine and/or 4 mg ephedrine IV.
2.3. Statistical methods The data were expressed as mean ± SD. The power calculation was done using Sample Power 3.0 (IBM Japan Inc, Tokyo, Japan) with a decrease in cerebral TOI values more than 8, which is equivalent to 13% decrease from the cerebral TOI limit of 60%, in response to the beach chair position during anesthesia as the primary end point [13,14]. In the current study, a sample size of 17 gave 80% power to the detected TOI change of 10% at a significance level of .05 (SD = 10). Statistical analysis using PASW Statistics 18 (IBM Japan Inc) was performed by the χ 2 test or repeated-measures analysis of variance followed by Scheffe test. Differences were considered to be statistically significant when the P value is less than .05.
3. Results Table 1 shows clinical and procedural characteristics of the study population. Patients in the risk factor 2 group were significantly older than those in other groups (Table 1). Risk factor 1 or 2 group involved more patients with hypertension, hypercholesterolemia and current smoking, and cardiac disease, diabetes, hypertension, hypercholesterolemia, and current smoking compared with the healthy group, respectively (Table 1). Preoperative mean blood pressure and heart rate, however, did not differ among groups (Fig. 1). Without Table 1
3 general anesthesia, the beach chair position with the 60° head-up tilt did not affect the mean blood pressure as well as heart rate (Fig. 1). Mean blood pressure under general anesthesia was significantly less than that before anesthesia in all groups (Fig. 1). However, the beach chair position did not further alter this reduction (Fig. 1). General anesthesia gave the tendency of decrease in heart rate whereas the head-up tilt itself mostly did not result in further heart rate changes, although it produced little differences at the 60° head-up tilt (Fig. 1). The mean phenylephrine dose to treat hypotension during general anesthesia with beach chair position was significantly more in the risk factor 2 group than in other groups (Table 2). All patients demonstrated normal preoperative baseline cerebral TOI values, and they did not show any abnormal cerebral TOI values in response to the beach chair position before anesthesia (Fig. 2). Irrespective of decreases in both blood pressure and heart rate, the beach chair position under general anesthesia did not alter the TOI values about 70% throughout the measurements (Fig. 2). No patient in this study documented adverse postoperative outcome.
4. Discussion The beach chair position with the 60° head-up tilt without anesthesia did not alter the mean blood pressure as well as heart rate in all studied groups. These results suggest that patients with and without cardiovascular risk factors in the current study preserved the physiological hemodynamic responses to head-up postures [15]. In all groups, general anesthesia gave the tendency of a decrease in the mean blood pressure and heart rate, whereas the head-up tilt itself basically did not result in further hemodynamic changes. The phenylephrine dose during general anesthesia with beach chair position was significantly larger in the risk factor 2 group than in other groups. Administration of vasoactive substances including phenylephrine to maintain mean blood pressure above 60 mm Hg should play a role in the stable hemodynamics during anesthesia irrespectively with the 60°
Demographic data of enrolled patients
Age (y), mean ± SD Sex (M/F) BMI (kg/m2), mean ± SD Hb (g/dL), mean ± SD Cardiac diseases (n) Diabetes mellitus (n) Hypertension (n) Hypercholesterolemia (n) Current smoking (n)
Healthy group (n = 28)
Risk factor 1 group (n = 33)
Risk factor 2 group (n = 30)
55 ± 16 18/10 23.2 ± 2.1 13.8 ± 1.5 0 0 0 0 0
59 ± 14 20/13 24.7 ± 4.4 13.9 ± 1.9 1 5 9⁎ 10 ⁎ 9⁎
65 ± 10 ⁎ 20/10 24.4 ± 2.6 13.6 ± 1.6 7⁎ 14 ⁎ 22 ⁎ 21 ⁎ 10 ⁎
Risk factor 1 group: patients with 1 risk factor; risk factor 2 group: patients with more than 1 risk factor. ⁎ P b .05 vs healthy group.
4
Y. Mori et al.
Fig. 1 Changes in mean blood pressure (left) and heart rate (right) according to 30° to 60° head-up tilt positions before and during general anesthesia. Values were significantly reduced compared with those before anesthesia. *P b .05.
head-up tilt. The α-adrenergic receptor activation induced by phenylephrine, at least partly, may also add some effects of reactive decrease in heart rate. Collectively, it might be concluded that general anesthesia using sevoflurane in combination with some vasoactive agents including phenylephrine may modulate hemodynamic changes according to the beach chair position. Indeed, a recent study has documented that sevoflurane-nitrous oxide, but not propofol-remifentanil, anesthesia affords an advantage to stabilize the mean blood pressure in the beach chair position [3]. Irrespective of decreases in both blood pressure and heart rate, the beach chair position under general anesthesia did not alter the cerebral TOI values throughout the current study. The beach chair position under general anesthesia with a careful blood pressure management that maintains mean Table 2 Phenylephrine and/or ephedrine requirement during measurements under general anesthesia in this study. Healthy group Risk factor 1 Risk factor 2 (n = 28) group (n = 33) group (n = 30) Phenylephrine 0.13 ± 0.20 (mg) Ephedrine 0.86 ± 3.33 (mg)
0.22 ± 0.38
0.48 ± 0.48 ⁎
0.73 ± 2.5
4.4 ± 9.00
Values are presented as means ± SD. ⁎ P b .05 vs healthy group.
blood pressure above 60 mm Hg probably does not alter cerebral oxygenation in patients with and without cardiovascular risk factors showing normal preoperative cerebral TOI values. The following factors may contribute to the desirable condition of cerebral oxygenation during the beach chair position in the current study. First, sevoflurane, compared with isoflurane, reportedly well preserves dynamic cerebral pressure autoregulation in humans [16]. Sevofluranenitrous oxide, but not propofol-remifentanil, anesthesia keeps up cerebral oxygen saturation measured by near-infrared spectroscopy as well as jugular venous bulb oxygen saturation in the beach chair position [3]. These results suggest that sevoflurane favors maintenance of cerebral oxygenation in the beach chair position. Second, previous studies indicated that the blood pressure management where it maintains mean blood pressure above 60 mm Hg, but not below this level, preserves cerebral oxygenation above the critical levels of 60% [17–19]. These results draw the conclusion that the mean blood pressure–oriented management during general anesthesia is necessary to avoid cerebral desaturation in the beach chair position. Indeed, Cullen and Kirby recommended treating blood pressure less than 80% of preoperative resting values during the beach chair position [20]. It is crucial for personnel involved in clinical anesthesia to remember the concept that some patients, who represent abnormal preoperative TOI values, may have much higher-than-expected lower limits of cerebral
Cerebral oxygenation in the beach chair position
Fig. 2
5
Changes in left and right cerebral TOIs (%) according to 30° to 60° head-up tilt positions before and during general anesthesia.
autoregulation [21]. Third, phenylephrine yields higher cerebral perfusion pressure in patients with traumatic brain injury compared with dopamine and norepinephrine, suggesting the desirable property of this vasoconstrictor agent in the cerebral circulation [22]. It is crucial to note that another vasoconstrictor agent vasopressin reduces cerebral oxygenation during the beach chair position despite the mean blood pressure elevation [4]. These results suggest that phenylephrine is probably one of the most valuable vasopressors, which are available in the clinical practice, to preserve cerebral oxygenation during anesthesia in the beach chair position. Clinicians should be cautious, however, because phenylephrine may cause a false-positive decrease in the near-infrared spectroscopy–determined cerebral oxygenation using INVOS by constricting extracranial vasculature [23]. Whether NIRO and INVOS similarly cause this phenomenon has been unclear, and further studies will require resolving the issue. The current study has several limitations to be evaluated and verified by future studies as follows. First, the blood pressure measurement might have to be done at the level of the head because the authors tried to show any changes of cerebral autoregulation according to the beach chair position in this study. However, using the measurement at the head level is not practical in the routine anesthetic management. In addition, the resistance to cerebral blood flow, but not the vertical distance above the heart, may solely determine cerebral perfusion pressure when one considers the siphon system [24,25]. In that occasion, the head elevation may not
decrease cerebral blood flow so long as mean arterial pressure at the level of the heart is not allowed to change, although this theory has not been proven in the beach chair position. Second, patients with more cardiovascular risk factors needed more vasopressors to maintain the mean blood pressure above the limitation of 60 mm Hg in the current study. We cannot rule out a possibility that this difference was due to the older study population in the risk factor 2 group. Third, the authors tried to evaluate changes in TOI values only for a short duration during anesthesia. Not only the positioning but also other conditions such as surgical bleeding or necessity for high-dose sevoflurane during anesthesia should affect the TOI values during surgery in the beach chair position. Fourth, the end-tidal carbon dioxide tension and sevoflurane concentration had to be set at the exactly same value during measurements in the anesthetic condition. In the current study, the beach chair position under general anesthesia did not alter cerebral oxygenation in patients with or without cardiovascular risk factors showing normal preoperative cerebral TOI values when the mean blood pressure was maintained above 60 mm Hg. It can be concluded that maintaining mean arterial blood pressure by vasopressors helps cerebral autoregulation and cerebral perfusion pressure in the beach chair position during general anesthesia as reflected by the minimal change in cerebral oxygenation monitoring. The authors would also emphasize the importance of preoperative cerebral TOI evaluation in these patients. The clinical implication of the current study,
6 however, has been still unclear because near-infrared spectroscopy detects a small area of the brain and cerebral ischemia is possible to occur in areas beyond the ability of this cerebral oxygen monitoring [7,26]. Further studies should determine the margin of safety in the anesthetic management with the beach chair position including the mean blood pressure limit to prevent cerebral desaturation.
References [1] Papadonikolakis A, Wiesler ER, Olympio MA, Poehling GG. Avoiding catastrophic complications of stroke and death related to shoulder surgery in the sitting position. Arthroscopy 2008;24:481-2. [2] Pohl A, Cullen DJ. Cerebral ischemia during shoulder surgery in the upright position: a case series. J Clin Anesth 2005;17:463-9. [3] Jeong H, Jeong S, Lim HJ, Lee J, Yoo KY. Cerebral oxygen saturation measured by near-infrared spectroscopy and jugular venous bulb oxygen saturation during arthroscopic shoulder surgery in beach chair position under sevoflurane-nitrous oxide or propofol-remifentanil anesthesia. Anesthesiology 2012;116:1047-56. [4] Cho SY, Kim SJ, Jeong CW, Jeong CY, Chung SS, Lee J, et al. Under general anesthesia arginine vasopressin prevents hypotension but impairs cerebral oxygenation during arthroscopic shoulder surgery in the beach chair position. Anesth Analg 2013;117:1436-43. [5] Smith M, Elwell C. Near-infrared spectroscopy: shedding light on the injured brain. Anesth Analg 2009;108:1055-7. [6] Moritz S, Kasprzak P, Arlt M, Taeger K, Metz C. Accuracy of cerebral monitoring in detecting cerebral ischemia during carotid endarterectomy: a comparison of transcranial Doppler sonography, near-infrared spectroscopy, stump pressure, and somatosensory evoked potentials. Anesthesiology 2007;107:563-9. [7] Yoshitani K, Kawaguchi M, Miura N, Okuno T, Kanoda T, Ohnishi Y, et al. Effects of hemoglobin concentration, skull thickness, and the area of the cerebrospinal fluid layer on near-infrared spectroscopy measurements. Anesthesiology 2007;106:458-62. [8] Tange K, Kinoshita H, Minonishi T, Hatakeyama N, Matsuda N, Yamazaki M, et al. Cerebral oxygenation in the beach chair position before and during general anesthesia. Minerva Anestesiol 2010;76: 485-9. [9] Fanning JP, Wong AA, Fraser JF. The epidemiology of silent brain infarction: a systematic review of population-based cohorts. BMC Med 2014;12:119.
Y. Mori et al. [10] Ritz K, Denswil NP, Stam OCG, Van Lieshout JJ, Daemen MJAP. Cause and mechanisms of intracranial atherosclerosis. Circulation 2014;130:1407-14. [11] Dalrymple DG, MacGowan SW, MacLeod GF. Cardiorespiratory effects of the sitting position in neurosurgery. Br J Anaesth 1979;51:1079-82. [12] Marshall WK, Bedford RF, Miller ED. Cardiovascular responses in the seated position: impact of four anesthetic techniques. Anesth Analg 1983;62:648-53. [13] Yoshitani K, Kawaguchi M, Tatsumi K, Kitaguchi K, Furuya H. A comparison of the INVOS 4100 and the NIRO 300 near-infrared spectroscopy. Anesth Analg 2002;94:586-90. [14] Al-Rawi PG, Kirkpatrick PJ. Tissue oxygen index: thresholds for cerebral ischemia using near-infrared spectroscopy. Stroke 2006;37:2720-5. [15] Smith JJ, Porth CM, Erickson M. Hemodynamic response to the upright posture. J Clin Pharmacol 1994;34:375-86. [16] Summors AC, Gupta AK, Matta BF. Dynamic cerebral autoregulation during sevoflurane anesthesia: a comparison with isoflurane. Anesth Analg 1999;88:341-5. [17] Murphy GS, Szokol JW, Marymont JH, Greenberg SB, Avram MJ, Vender JS, et al. Cerebral oxygen desaturation events assessed by nearinfrared spectroscopy during shoulder arthroscopy in the beach chair and lateral decubitus positions. Anesth Analg 2010;111:496-505. [18] Moerman AT, De Hert SG, Jacobs TF, De Wilde LF, Wouters PF. Cerebral oxygen desaturation during beach chair position. Eur J Anaesthesiol 2012;29:82-7. [19] Closhen D, Berres M, Werner C, Engelhard K, Schramm P. Influence of beach chair position on cerebral oxygen saturation: a comparison of INVOS and FORE-SIGHT cerebral oximeter. J Neurosurg Anesthesiol 2013;25:414-9. [20] Cullen DJ, Kirby RR. Beach chair position may decrease cerebral perfusion: catastrophic outcomes have occurred. APSF Newsl 2007;22:25-7. [21] Drummond JC. The lower limit of autoregulation: time to revise our thinking? Anesthesiology 1997;86:1431-3. [22] Sookplung P, Siriussawakul A, Malakouti A, Sharma D, Wang J, Souter MJ, et al. Vasopressor use and effect on blood pressure after severe adult traumatic brain injury. Neurocrit Care 2011;15:46-54. [23] Ogoh S, Sato K, Okazaki K, Miyamoto T, Secher F, Sørensen H, et al. A decrease in spatially resolved near-infrared spectroscopy-determined frontal lobe tissue oxygenation by phenylephrine reflects reduced skin blood flow. Anesth Analg 2014;118:823-9. [24] Hicks JW, Munis JR. The siphon controversy counterpoint: the brain need not be “baffling”. Am J Physiol 2005;289:R629-32. [25] Munis JR, Lozada LJ. Giraffes, siphons, and starling resistors: cerebral perfusion pressure revisited. J Neurosurg Anesthesiol 2000;12:290-6. [26] Quaresima V, Sacco S, Totaro R, Ferrari M. Noninvasive measurement of cerebral hemoglobin saturation using two near infrared spectroscopy approaches. J Biomed Opt 2000;5:201-5.