Videolaryngoscopy for Physician-Based, Prehospital Emergency Intubation: A Prospective, Randomized, Multicenter Comparison of Different Blade Types Using A.P. Advance, C-MAC System, and KingVision.

BACKGROUND: Videolaryngoscopy is a valuable technique for endotracheal intubation. When used in the perioperative period, different videolaryngoscopes vary both in terms of technical use and intubation success rates. However, in the prehospital environment, the relative performance of different videolaryngoscopic systems is less well studied. METHODS: We conducted this prospective, randomized, multicenter study at 4 German prehospital emergency medicine centers. One hundred sixty-eight adult patients requiring prehospital emergency intubation were treated by an emergency physician and randomized to 1 of 3 portable videolaryngoscopes (A.P. Advance, C-MAC PM, and channeled blade KingVision) with different blade types. The primary outcome variable was overall intubation success and secondary outcomes included first-attempt intubation success, glottis visualization, and difficulty with handling the devices. P values for pairwise comparisons are corrected by the Bonferroni method for 3 tests (P[BF]). All presented P values are adjusted for center. RESULTS: Glottis visualization was comparable with all 3 devices. Overall intubation success for A.P. Advance, C-MAC, and KingVision was 96%, 97%, and 61%, respectively (overall: P < .001, A.P. Advance versus C-MAC: odds ratio [OR], 0.97, 95% confidence interval [CI], 0.13-7.42, P[BF] > 0.99; A.P. Advance versus KingVision: OR, 0.043, 95% CI, 0.0088-0.21, P[BF] < 0.001; C-MAC versus KingVision: OR, 0.043, 95% CI, 0.0088-0.21, P[BF] < 0.001). Intubation success on the first attempt with A.P. Advance, C-MAC, and KingVision was 86%, 85%, and 48%, respectively (overall: P < .001, A.P. Advance versus C-MAC: OR, 0.89, 95% CI, 0.31-2.53, P[BF] > 0.99; A.P. Advance versus KingVision: OR, 0.24, 95% CI, 0.055-0.38, P[BF] = 0.0054; C-MAC versus KingVision: OR, 0.21, 95% CI, 0.043-.34, P[BF] < 0.003). Direct laryngoscopy for successful intubation with the videolaryngoscopic device was necessary with the A.P. Advance in 5 patients, and with the C-MAC in 4 patients. In the KingVision group, 21 patients were intubated with an alternative device. CONCLUSIONS: During prehospital emergency endotracheal intubation performed by emergency physicians, success rates of 3 commercially available videolaryngoscopes A.P. Advance, C-MAC PM, and KingVision varied markedly. We also found that although any of the videolaryngoscopes provided an adequate view, actual intubation was more difficult with the channeled blade KingVision.

Improvement in glottic visualisation by using the C-MAC PM video laryngoscope as a first-line device for out-of-hospital emergency tracheal intubation: An observational study.

BACKGROUND: Out-of-hospital tracheal intubation is associated with life-threatening complications. To date, no study has compared direct and video laryngoscopic views simultaneously in the same patients in an out-of-hospital setting. OBJECTIVES: The aim of this study was to determine the effect of C-MAC PM video laryngoscope on laryngeal view, compared with direct laryngoscopy, and to estimate possible consequences for patient safety. DESIGN: An observational, single-centre study. SETTING: Helicopter Emergency Medical Service (HEMS) 'CHRISTOPH 22', Ulm, Germany. PATIENTS: Two-hundrend and twenty-eight emergency patients undergoing airway management out of hospital. INTERVENTIONS: Laryngoscopy and tracheal intubation using C-MAC PM video laryngoscope. For all intubations, the HEMS physician used CMAC PM as the first-line device and performed an initial direct laryngoscopy followed by a video laryngoscopy, without changing the laryngoscope blade. MAIN OUTCOME MEASURES: The difference in laryngeal view was recorded as well as the number of intubation attempts along with the success rate and difficulties in airway management. Improvement in glottic visualisation from Cormack and Lehane grade III/IV to I/II was rated as being clinically relevant. RESULTS: During a 20-month study period, a total of 228 out-of-hospital emergency patients requiring tracheal intubation were included. The overall success rate in securing the airway was 100%. For 226 patients (99.1%), tracheal intubation was successful with two or fewer attempts. For comparison of direct and indirect laryngoscopic views, five patients were excluded because of the use of an indirect laryngoscope blade. Of 223 patients, 120 had a glottic view rated as Cormack and Lehane grade II to IV with direct laryngoscopy; in these patients, visualisation of the glottis was significantly improved with the C-MAC PM video laryngoscope (P < 0.001). In 56 patients (25.1%), improvement of glottic visualisation was clinically relevant (P < 0.001). CONCLUSION: Use of the C-MAC PM video laryngoscope is associated with improved visualisation of the glottis according to the Cormack and Lehane grading system and an excellent success rate for out-of-hospital tracheal intubation. These results suggest that the use of C-MAC PM as a first-line device for tracheal intubation by out-of-hospital emergency medical services is a safe procedure.

A randomised, controlled crossover comparison of the C-MAC videolaryngoscope with direct laryngoscopy in 150 patients during routine induction of anaesthesia.

BACKGROUND: The C-MAC® (Karl Storz, Tuttlingen, Germany) has recently been introduced as a new device for videolaryngoscopy guided intubation. The purpose of the present study was to compare for the first time the C-MAC with conventional direct laryngoscopy in 150 patients during routine induction of anaesthesia. METHODS: After approval of the institutional review board and written informed consent, 150 patients (ASA I-III) with general anaesthesia were enrolled. Computer-based open crossover randomisation was used to determine the sequence of the three laryngoscopies: Conventional direct laryngoscopy (HEINE Macintosh classic, Herrsching, Germany; blade sizes 3 or 4; DL group), C-MAC size 3 (C-MAC3 group) and C-MAC size 4 (C-MAC4 group) videolaryngoscopy, respectively. After 50 patients, laryngoscopy technique in the C-MAC4 group was changed to the straight blade technique described by Miller (C-MAC4/SBT). RESULTS: Including all 150 patients (70 male, aged (median [range]) 53 [20-82] years, 80 [48-179] kg), there was no difference of glottic view between DL, C-MAC3, C-MAC4, and C-MAC4/SBT groups; however, worst glottic view (C/L 4) was only seen with DL, but not with C-MAC videolaryngoscopy. In the subgroup of patients that had suboptimal glottic view with DL (C/L≥2a; n = 24), glottic view was improved in the C-MAC4/SBT group; C/L class improved by three classes in 5 patients, by two classes in 2 patients, by one class in 8 patients, remained unchanged in 8 patients, or decreased by two classes in 1 patient. The median (range) time taken for tracheal intubation in the DL, C-MAC3, C-MAC4 and C-MAC4/SBT groups was 8 sec (2-91 sec; n = 44), 10 sec (2-60 sec; n = 37), 8 sec (5-80 sec; n = 18) and 12 sec (2-70 sec; n = 51), respectively. CONCLUSIONS: Combining the benefits of conventional direct laryngoscopy and videolaryngoscopy in one device, the C-MAC may serve as a standard intubation device for both routine airway management and educational purposes. However, in patients with suboptimal glottic view (C/L≥2a), the C-MAC size 4 with straight blade technique may reduce the number of C/L 3 or C/L 4 views, and therefore facilitate intubation. Further studies on patients with difficult airway should be performed to confirm these findings.

The C-MAC videolaryngoscope for prehospital emergency intubation: a prospective, multicentre, observational study.

BACKGROUND: In this preliminary prospective observational study at four physician-led air rescue centres, the efficacy of the C-MAC (Karl Storz, Tuttlingen, Germany), a new portable videolaryngoscope, was evaluated during prehospital emergency endotracheal intubations. METHODS: 80 consecutive patients requiring prehospital emergency intubation, treated by a physician introduced in the use of the C-MAC were enrolled in this study. RESULTS: Indication for prehospital intubation was trauma in 45 cases (including maxillo-facial trauma in 10 cases), cardiopulmonary resuscitation in 14 cases, and unconsciousness of neurological aetiology and cardiogenic dyspnoea in 21 cases. Forty-nine patients were intubated with a C-MAC blade size 3, and 31 with a C-MAC blade size 4. Median time to successful intubation was 20 (min-max: 5-300) seconds; 63 patients were intubated on the first attempt, 13 on the second and four after more than two attempts. A Cormack-Lehane class 1 view of the glottis was seen in 46 patients, class 2a view in 21, class 2b in eight, class 3 in three and class 4 in two. Six patients could not be intubated with the videolaryngoscopic view, but were successfully intubated at the same attempt using the C-MAC with the direct laryngoscopic view. CONCLUSION: The C-MAC videolaryngoscope was suitable for prehospital emergency endotracheal intubations with complicated airway conditions, such as maxillo-facial trauma. The option to perform direct laryngoscopy and videolaryngoscopy with the same device appears to be exceptionally important in the prehospital setting.

First clinical evaluation of the C-MAC D-Blade videolaryngoscope during routine and difficult intubation.

In the present preliminary study we evaluated the C-MAC® D-Blade (Karl Storz, Tuttlingen, Germany), a new videolaryngoscopic C-MAC blade for difficult intubation, during both routine and difficult intubations. First, both the conventional direct laryngoscopy and the D-Blade were used in 15 consecutive patients with normal airways during routine induction of anesthesia. Second, the D-Blade was used as a rescue device in 20 of 300 (6.7%) consecutive patients, when conventional direct laryngoscopy failed. In the 15 patients during routine induction of anesthesia, with direct laryngoscopy, a Cormack-Lehane (C/L) grade 1 and grade 2a view was seen in 7 and 8 patients, respectively. It was possible to insert the D-Blade and to get a video view of the glottis on the first attempt in all patients; with the D-Blade, all 15 patients had a C/L 1 view. The time to successful intubation with the D-Blade was 15 (8-26) seconds (median (range)). In the 20 patients, in whom unexpected difficulty with direct laryngoscopy was observed, C/L grades 3 and 4 were present in 15 and 5 patients, respectively. With the use of the D-Blade, indirect C/L video view improved to C/L class 1 in 15 patients, and to 2a in 5 patients, respectively. The time from touching the laryngoscope to optimal laryngoscopic view was 11 (5-45) seconds and for successful intubation 17 (3-80) seconds. In all 35 patients, with the D-Blade no direct view of the glottis was possible and subsequently a semiflexible tube guide was required.

Effects of cerebral hypoperfusion on bispectral index: a randomised, controlled animal experiment during haemorrhagic shock.

BACKGROUND: The aim of this porcine haemorrhagic shock model was to investigate the changes of bispectral index (BIS) after slow and fast recovery of cerebral perfusion, and its correlation with plasma propofol concentrations. METHODS: After Animal Investigational Committee approval, 16 pigs during propofol anaesthesia underwent a liver trauma with severe hypotension, and were randomly assigned to receive therapy for either slow recovery (fluid resuscitation; slow group; n=8) or fast recovery of cerebral perfusion (vasopressor combined with hypertonic-saline-starch; fast group; n=8), respectively. Cerebral perfusion pressure (CPP=MAP-ICP), cerebral tissue oxygenation index (TOI), BIS, and plasma concentrations of propofol and haemoglobin were measured at baseline (Pre-shock), haemodynamic decompensation (Shock), and 5 (Therapy) and 30 min (End) after therapy, respectively. RESULTS: CPP, TOI, and BIS decreased significantly during shock (pre-shock vs. shock, fast: CPP: 65+/-14 vs. 15+/-4 mmHg; TOI: 64+/-6 vs. 47+/-7%; BIS 60+/-5 vs. 9+/-10; slow: CPP: 60+/-12 vs. 13+/-7 mmHg; TOI: 68+/-7 vs. 49+/-7%; BIS 63+/-5 vs. 13+/-12; P<0.05). In the fast group, CPP, TOI, and BIS increased after therapy compared to the slow group (Therapy, fast: CPP: 47+/-15 mmHg, TOI: 61+/-7%, BIS: 47+/-21; slow: CPP: 18+/-9 mmHg, TOI: 51+/-5%, BIS: 21+/-19; P<0.05). Propofol and haemoglobin concentrations were comparable between groups throughout the resuscitation phase. CONCLUSIONS: In a haemorrhagic shock scenario, therapies with different impact on cerebral perfusion resulted in differing changes of BIS values, while plasma propofol and haemoglobin concentrations were comparable during the resuscitation phase; this suggests that BIS may also have reflected changes of cerebral perfusion.

Laryngeal tube S II, laryngeal tube S disposable, Fastrach laryngeal mask and Fastrach laryngeal mask disposable during elective surgery: a randomized controlled comparison between reusable and disposable supraglottic airway devices.

BACKGROUND AND OBJECTIVE: Analogue disposable devices of the laryngeal tube S II (LTS II) and the Fastrach laryngeal intubation mask (ILMA, Fastrach), namely the laryngeal tube disposable (LTS-D) and the Fastrach laryngeal intubation mask disposable (Fastrach-D), have recently been introduced. The purpose of this study was to compare each reusable device with the corresponding disposable one, during routine surgery. METHODS: After informed consent, 120 American Society of Anesthesiologists I-III patients scheduled for routine minor surgery were randomly allocated to the LTS II (n = 30), the LTS-D (n = 30), the Fastrach (n = 30) and the Fastrach-D (n = 30) groups, respectively. Overall insertion success rates, time to first sufficient ventilation (V(e)t > or = 200 ml), resulting airway leak pressures (ALPs), subjective assessment of handling as well as patient comfort were determined. RESULTS: Insertion success rates of the LTS II, LTS-D, Fastrach and Fastrach-D were 30/30, 29/30, 30/30 and 30/30, respectively. Time to successful insertion in the LTS II vs. the LTS-D group, as well as in the Fastrach vs. the Fastrach-D group, showed significant differences [median (min-max) s: 38 (13-187), 23 (9-108), P < 0,05; 27.5 (6-110), 16 (8-82), P < 0.05]. The highest ALP could be observed in the LTS-D group [median (min-max): 40 (16-40), P < 0.001 vs. all other devices] and the lowest ALP in the Fastrach-D group [median (min-max): 24.5 (12-40)]. ALP did not differ significantly in any group during variation of cuff volume by +/-20 ml. Subjective assessment of handling was significantly (P < 0.001) better in the LTS-D group than in the LTS II, Fastrach and Fastrach-D groups. CONCLUSION: LTS II, LTS-D, Fastrach and Fastrach-D were all suitable for routine airway management. The LTS-D showed the best properties in terms of airway sealing and handling.

The C-MAC videolaryngoscope: first experiences with a new device for videolaryngoscopy-guided intubation.

We studied the efficacy of the C-MAC (Karl Storz, Tuttlingen, Germany), a new portable videolaryngoscope, in 60 patients during routine induction of anesthesia. It was possible to insert the blade (Size 3) of the C-MAC and to get a view of the glottis on the first attempt in all patients. Tracheal intubation also was successful in all 60 patients; 52 patients were intubated on the first attempt, 6 on the second, and 2 on the third. In 8 patients (13%), a gum elastic bougie guide was required. A Cormack-Lehane Class 1 view of the glottis was seen in 30 patients without external manipulation and in 45 with external manipulation, Class 2a view in 22 without and 12 with, Class 2b in 2 without, and Class 3 in 2 without manipulation. The median time taken for tracheal intubation was 16 s (range, 6-58 s). In addition, we describe our experience with 3 patients in whom we had unexpected difficulty with direct laryngoscopy with a conventional Macintosh laryngoscope (Cormack-Lehane Class 3, 4, and 4, respectively). These patients' airways were successfully managed on the first attempt when using the C-MAC Size 4 blade (improvement to Cormack-Lehane Class 1, 2a, and 2b, respectively) in a modified manner by uploading the epiglottis, which is known as "straight blade technique."

Laryngeal tube S II, ProSeal laryngeal mask, and EasyTube during elective surgery: a randomized controlled comparison with the endotracheal tube in nontrained professionals.

BACKGROUND AND OBJECTIVE: EasyTube (EZT), ProSeal laryngeal mask airway (PLMA), and Laryngeal tube S II (LTS II) have recently been introduced as supraglottic airway devices and have been proposed as emergency airway alternatives. The purpose of this study was to compare the performance of the three devices, if used by anaesthesiologists without extensive hands-on training, with the endotracheal tube during routine surgical procedures. METHODS: After informed consent, 88 ASA I-II patients scheduled for routine minor surgery were randomly allocated to EZT (n=22), PLMA (n=22), and LTS II (n=22) groups and the endotracheal tube (n=22) group, respectively. Overall success rates, insertion times, cuff pressures, and resulting airway leak pressures as well as subjective assessment of handling were determined. RESULTS: Overall insertion success rate of the EZT, PLMA, LTS II, and endotracheal tube was 14 out of 22 (64%), 20 out of 22 (91%), 21 out of 22 (96%), and 21 out of 22 (96%), respectively. Time to first successful ventilation with the EZT was significantly (P<0.05) longer than that with PLMA, LTS II, and endotracheal tube [median (minimum-maximum): 56 (27-150), 25 (12-70), 24 (11-150), and 20 (8-74) s, respectively]. The lowest airway leak pressure could be observed with the EZT [median (minimum-maximum), 19 (9-40) cmH2O] and the highest airway leak pressure with the LTS II [median (minimum-maximum), 40 (22-40) cmH2O]. Subjective assessment of handling was significantly (P<0.05) poorer in the EZT group compared with PLMA, LTS II, and endotracheal tube groups, respectively. CONCLUSION: In contrast to the EZT, both PLMA and LTS II proved to be suitable for routine airway management by anaesthesiologists without extensive hands-on device training.

Cerebral effects of three resuscitation protocols in uncontrolled haemorrhagic shock: a randomised controlled experimental study.

BACKGROUND: To compare haemodynamic and cerebral variables during aggressive fluid resuscitation vs. administration of a hypertonic starch solution (HS) combined with either noradrenaline [norepinephrine] or arginine vasopressin in an animal model of uncontrolled haemorrhagic shock. METHODS: After Animal Investigational Committee approval, 24 anaesthetised pigs underwent a liver trauma. At haemodynamic decompensation, animals were randomly assigned to receive fluid resuscitation (6% HES 130/0.4, 20 mL/kg, and Ringer, 40 mL/kg; FR group, n=8), or noradrenaline (bolus 20 microg/kg, continuously 1 microg/kg/min) combined with HS (7.2% NaCl/6% HES 200/0.5; 4 mL/kg) (n=8; NA/HS group), or vasopressin (bolus 0.2U/kg, continuously 0.04 U/kg/min) combined with HS (4 mL/kg) (n=8; AVP/HS group), respectively. Thirty minutes after drug administration, bleeding was controlled manually. RESULTS: Mean arterial blood pressure (MAP), cerebral perfusion pressure (CPP), and brain tissue oxygen pressure (P(bt)O(2)) decreased significantly with haemorrhage in all groups (p<0.05). AVP/HS resulted in a faster and higher increase of MAP and CPP compared to both NA/HS and FR (p<0.001 vs. FR; p<0.01 vs. NA/HS). Compared to FR, P(bt)O(2) increased faster with AVP/HS and NA/HS (p<0.05) after therapy, and ICP was lower at the end of the study period (p<0.05). All animals (8/8) of the AVP/HS group survived, compared to 4/8 and 4/8 in the NA/HS and FR group, respectively (p=0.07). CONCLUSIONS: Following uncontrolled haemorrhagic shock in this animal model, combination of HS with arginine vasopressin increased CPP and cerebral oxygenation faster than aggressive fluid resuscitation, without re-increasing ICP.

The reliability of pulse contour-derived cardiac output during hemorrhage and after vasopressor administration.

BACKGROUND: Reliable measurement of cardiac output (CO) is important in the critically ill. Pulse contour-derived CO (PCCO) has been evaluated during stable hemodynamics, but is sensitive to changes in vascular tone and has not been validated under conditions of changing hemodynamics. Furthermore, PCCO requires calibration for the individual vascular impedance by transpulmonary thermodilution CO (TPCO), and the required frequency of recalibration to maintain accurate measurements, especially during changing conditions, has not been confirmed. We compared PCCO measurements of CO with TPCO and continuous and bolus pulmonary artery CO (CCO and BCO, respectively) during conditions of uncontrolled hemorrhage and resuscitation with norepinephrine. METHODS: Thirteen pigs were anesthetized and instrumented for determination of CO by BCO and CCO, respectively, as well as bolus TPCO and PCCO. Uncontrolled hemorrhage was accomplished by liver incision. When mean arterial blood pressure was <25 mm Hg, or heart rate declined progressively to <20% of its peak value, vasopressor therapy was started. TPCO and BCO were performed after induction of anesthesia and 15 min after start of therapy, and PCCO and CCO were obtained repeatedly. CO measurements were compared using Bland-Altman analysis. RESULTS: Mean arterial blood pressure, CO and systemic vascular resistance decreased after hemorrhage (P < 0.001 and <0.01, respectively). Bias and limits of agreement between CCO and PCCO (0.54 L/min; 1.46 L/min) increased after hemorrhage (-3.49; 6.12) and further deteriorated after norepinephrine administration (-8.01; 9.9). After recalibration, bias and limits of agreement returned to -0.51 and 1.28. CONCLUSIONS: PCCO needs frequent recalibration during hemorrhage and after vasopressor administration.

A comparison of transcranial Doppler with near infrared spectroscopy and indocyanine green during hemorrhagic shock: a prospective experimental study.

INTRODUCTION: The present study was designed to compare cerebral hemodynamics assessed using the blood flow index (BFI) derived from the kinetics of the tracer dye indocyanine green (ICG) with transcranial Doppler ultrasound (TCD) in an established model of hemorrhagic shock. METHODS: After approval from the Animal Investigational Committee, 20 healthy pigs underwent a simulated penetrating liver trauma. Following hemodynamic decompensation, all animals received a hypertonic-isooncotic hydroxyethyl starch solution and either arginine vasopressin or norepinephrine, and bleeding was subsequently controlled. ICG passage through the brain was monitored by near infrared spectroscopy. BFI was calculated by dividing maximal ICG absorption change by rise time. Mean blood flow velocity (FVmean) of the right middle cerebral artery was recorded by TCD. FVmean and BFI were assessed at baseline (BL), at hemodynamic decompensation, and repeatedly after control of bleeding. RESULTS: At hemodynamic decompensation, cerebral perfusion pressure (CPP), FVmean and BFI dropped compared to BL (mean +/- standard deviation; CPP 16 +/- 5 mmHg versus 70 +/- 16 mmHg; FVmean 4 +/- 5 cm x s(-1) versus 28 +/- 9 cm x s(-1); BFI 0.008 +/- 0.004 versus 0.02 +/- 0.006; p < 0.001). After pharmacological intervention and control of bleeding, FVmean and BFI increased close to baseline values (FVmean 23 +/- 9 cm x s(-1); BFI 0.02 +/- 0.01), respectively. FVmean and BFI were significantly correlated (r = 0.62, p < 0.0001). CONCLUSION: FVmean and BFI both reflected the large variations in cerebral perfusion during hemorrhage and after resuscitation and were significantly correlated. BFI is a promising tool to monitor cerebral hemodynamics at the bedside.

Heart rate variability-guided prophylactic treatment of severe hypotension after subarachnoid block for elective cesarean delivery.

BACKGROUND: Baseline low-to-high frequency ratio (LF/HF) of heart rate variability predicted hypotension after subarachnoid block (SAB). LF/HF-guided treatment of hypotension with vasopressors or colloids was investigated. METHODS: In 80 women scheduled to undergo cesarean delivery during SAB, LF/HF and systolic blood pressure (SBP) were analyzed. Patients were randomly assigned to a control group (n = 40) or a treatment group (n = 40). Control patients were assigned by their baseline LF/HF to one of two subgroups: LF/HF less than 2.5 or LF/HF greater than 2.5. Treatment patients with baseline LF/HF greater than 2.5 were treated with vasopressor infusion right after SAB (n = 20) or colloid prehydration until LF/HF decreased below 2.5 (n = 20). The incidences of hypotension (SBP < 80 mmHg) and hypertension (SBP > 140 mmHg) were investigated. LF/HF is presented as median and range, and SBP is presented as mean +/- SD. RESULTS: Three of 17 control patients with low baseline LF/HF (1.7 [1.3/1.8]) demonstrated hypotension, and mean SBP remained stable (lowest SBP = 105 +/- 14 mmHg). In contrast, 20 of 23 control patients with high baseline LF/HF (3.8 [3.3/4.8]; P < 0.0001 vs. low baseline LF/HF) demonstrated hypotension after SAB: lowest SBP = 78 +/- 15 mmHg (P < 0.0001 vs. lowest SBP of control group with low baseline LF/HF). LF/HF-guided vasopressor therapy prevented hypotension in 19 of 20 patients: baseline SBP = 123 +/- 15 mmHg, lowest SBP = 116 +/- 17 mmHg. Mean prophylactic colloid infusion of 1,275 +/- 250 ml reduced elevated baseline LF/HF from 5.4 (4.1/7.5) to 1.3 (0.8/1.59) (P < 0.0001). Hypotension was prevented in 17 of 20 patients: baseline SBP = 115 +/- 13 mmHg, lowest SBP = 104 +/- 19 mmHg. No hypertensive episode was recognized. CONCLUSIONS: LF/HF may be a tool to guide prophylactic therapy of patients at high risk for hypotension after SAB. Vasopressor therapy tended to be more effective compared with colloid prehydration.