Karl-Heinz Stadlbauer

Endogenous vasopressin and copeptin response in multiple trauma patients

Endogenous arginine vasopressin (AVP) levels in multiple trauma patients are unknown. Arginine vasopressin is considered to play an important role in severe hemorrhage. In this prospective study, 87 multiple trauma patients (Injury Severity Score >15) and 50 healthy volunteers were enrolled. On admission to the emergency department (ED), demographic, clinical, and laboratory data were documented, and blood was sampled for determination of AVP (radioimmunosassay) and copeptin, a stable fragment of the AVP precursor (immunoluminometric assay). In patients requiring intensive care unit (ICU) therapy, blood and data sampling were repeated at 4, 6, and 24 h after ED admission. Linear logistic and mixed-effects regression analyses were used for statistical analysis. On ED admission, AVP plasma concentrations (43.2 ± 84.9 pM) were significantly increased when compared with controls (0.92 ± 0.44 pM, P < 0.001). Plethysmographic oxygen saturation was the only parameter independently associated with AVP (regression coefficient, −0.126; 95% confidence interval, −0.237 to −0.014; P = 0.03). No correlation was observed between AVP and survival (P = 0.62), hemodynamic variables (systolic arterial pressure, P = 0.24; MAP, P = 0.59; diastolic arterial pressure, P = 0.74; central venous pressure, P = 0.36), or brain trauma (P = 0.46). In ICU patients, AVP decreased during the first 24 h (P < 0.001) and was independently associated with heart rate (P = 0.02) and blood glucose (P = 0.009). Copeptin concentrations were correlated with AVP (r2 = 0.718, P < 0.001). In conclusion, AVP was significantly increased in multiple trauma patients and seems to be an integral part of the neuroendocrine response to severe injury. In ICU patients, AVP decreased to moderately elevated levels within 24 h after ED admission.

Neither vasopressin nor amiodarone improve CPR outcome in an animal model of hypothermic cardiac arrest

Background:  Aim of this experimental animal study was to investigate the influence of vasopressin and amiodarone on cardiopulmonary resuscitation (CPR) outcome in a pig model of hypothermic cardiac arrest.

Cutaneous vascular reactivity and flow motion response to vasopressin in advanced vasodilatory shock and severe postoperative multiple organ dysfunction syndrome

IntroductionDisturbances in microcirculatory homeostasis have been hypothesized to play a key role in the pathophysiology of multiple organ dysfunction syndrome and vasopressor-associated ischemic skin lesions. The effects of a supplementary arginine vasopressin (AVP) infusion on microcirculation in vasodilatory shock and postoperative multiple organ dysfunction syndrome are unknown.MethodIncluded in the study were 18 patients who had undergone cardiac or major surgery and had a mean arterial blood pressure below 65 mmHg, despite infusion of more than 0.5 μg/kg per min norepinephrine. Patients were randomly assigned to receive a combined infusion of AVP/norepinephrine or norepinephrine alone. Demographic and clinical data were recorded at study entry and after 1 hour. A laser Doppler flowmeter was used to measure the cutaneous microcirculatory response at randomization and after 1 hour. Reactive hyperaemia and oscillatory changes in the Doppler signal were measured during the 3 minutes before and after a 5-minute period of forearm ischaemia.ResultsPatients receiving AVP/norepinephrine had a significantly higher mean arterial pressure (P = 0.047) and higher milrinone requirements (P = 0.025) than did the patients who received norepinephrine only at baseline. Mean arterial blood pressure significantly increased (P < 0.001) and norepinephrine requirements significantly decreased (P < 0.001) in the AVP/norepinephrine group. Patients in the AVP/norepinephrine group exhibited a significantly higher oscillation frequency of the Doppler signal before ischaemia and during reperfusion at randomization. During the study period, there were no differences in either cutaneous reactive hyperaemia or the oscillatory pattern of vascular tone between groups.ConclusionSupplementary AVP infusion in patients with advanced vasodilatory shock and severe postoperative multiple organ dysfunction syndrome did not compromise cutaneous reactive hyperaemia and flowmotion when compared with norepinephrine infusion alone.

Gum elastic bougie-guided insertion of the ProSeal laryngeal mask airway is superior to the digital and introducer tool techniques in patients with simulated difficult laryngoscopy using a rigid neck collar.

BACKGROUND: We compared three techniques for insertion of the laryngeal mask airway ProSeal™ (PLMA) in patients with simulated difficult laryngoscopy using a rigid neck collar. METHODS: Ninety-nine anesthetized healthy female patients aged 19–68 yr were randomly allocated for PLMA insertion using the digital, introducer tool (IT) or guided techniques. Difficult laryngoscopy was simulated using a rigid neck collar. The laryngoscopic view was graded before PLMA insertion. The digital and IT techniques were performed according to the manufacturer’s instructions. The guided technique involved priming the drain tube with an Eschmann tracheal tube introducer, placing the introducer in the esophagus under direct vision and railroading the PLMA into position. Failed insertion was defined by any of the following criteria: 1) failed pharyngeal placement, 2) malposition, and 3) ineffective ventilation. RESULTS: The median laryngoscopic view was 3 and the mean interincisor distance was 3.3 cm. Insertion was more frequently successful with the guided technique at the first attempt (guided 100%, digital 64%, IT 61%; P < 0.0001), but success after three attempts was similar (guided 100%, digital 94%, IT 91%). The time taken for successful placement was similar among groups at the first attempt, but was shorter for the guided technique after three attempts (guided 31 ± 8 s, digital 49 ± 28 s, IT 54 ± 37 s; P < 0.02). CONCLUSION: The guided insertion technique is more frequently successful than the digital or IT techniques in patients with simulated difficult laryngoscopy using a rigid neck collar.

Regional and local brain oxygenation during hemorrhagic shock: a prospective experimental study on the effects of small-volume resuscitation with norepinephrine.

BACKGROUND Patients with uncontrolled hemorrhage may benefit if resuscitation with large amounts of fluids is replaced by a small volume or vasopressor until surgery. Norepinephrine (NE) is commonly used as a vasopressor to control hypotension. The purpose of this study was to compare the effects of hypertonic-hyperoncotic saline starch solution (HHS) either alone or combined with NE on brain tissue oxygen pressure (PbtO2) and brain oxygen saturation (rSO2) in a model of uncontrolled hemorrhage. METHODS After approval of the animal investigation committee, 22 anesthetized pigs underwent simulated penetrating liver trauma. At hemodynamic decompensation, animals were randomly assigned to receive HHS (Hyperhaes; 4 mL/kg; n = 8) with normal saline placebo, low-dose NE (low NE; 500 microg, and 1 microg/kg/min; n = 7), or high-dose NE (high NE; 1,000 microg, and 1 microg/kg/min; n = 7). Bleeding was controlled manually 30 minutes after drug administration. RESULTS Cerebral perfusion pressure (CePP), PbtO2, and rSO2 decreased with hemorrhage in all groups (baseline vs. decompensation, CePP-HHS, 83 +/- 5 mm Hg vs. 9 +/- 1 mm Hg; low NE, 67 +/- 6 mm Hg vs. 16 +/- 2 mm Hg; high NE, 77 +/- 7 mm Hg vs. 15 +/- 1 mm Hg. PbtO2-HHS, 100% vs. 29%; low NE, 100% vs. 33%; high NE, 100% vs. 27%. rSO2-HHS, 100% vs. 70%; low NE, 100% vs. 76%; high NE, 100% vs. 63%). Therapy with HHS, low NE, and high NE resulted in a comparable increase of CePP, PbtO2, and rSO2, respectively (5 minutes after therapy, CePP-HHS, 29 +/- 3 mm Hg; low NE, 27 +/- 3 mm Hg; high NE, 28 +/- 3 mm Hg. PbtO2-HHS, 207%; low NE, 129%; high NE, 170%. rSO2-HHS, 94%; low NE, 83%; high NE, 87%). Overall survival was six of eight, four of seven, and six of seven, respectively. CONCLUSION After uncontrolled hemorrhagic shock, addition of different dosages of NE to HHS, compared with HHS alone, showed no beneficial effect on CePP, rSO2, or PbtO2.

A Prediction Model for Out-of-Hospital Cardiopulmonary Resuscitation

BACKGROUND: We created a prediction model to be used in cardiopulmonary resuscitation (CPR) attempts as a decision tool to omit futile CPR attempts and to save resources. METHODS: In this post hoc analysis, we assessed predictive parameters for neurological recovery after successful CPR. The original study was designed as a blinded, randomized, prospective, controlled, multicenter clinical trial. RESULTS: We identified 1166 prehospital cardiac arrest patients being treated with advanced cardiac life support. Seven hundred eighty-six of 1166 patients (67.4%) died at the scene and 380 of 1166 (32.6%) were brought to the hospital. Two hundred sixty-five of 1166 patients (22.7%) died in the hospital. One hundred fifteen of 1166 (9.8%) were discharged from the hospital and 92 of the 115 patients (80%) could be followed-up. Good cerebral performance was regained by 54% of discharged patients (50 of 92 patients). In 46% of patients (42/92), unconsciousness or severe disability remained. Ventricular fibrillation was more likely to have occurred in patients with good neurological recovery (42/50 = 84.0%), whereas asystole was more likely in patients with poor neurological recovery (9/42 = 21.4%). A score was developed to predict the probability of death using logistic regression analysis. Predicting death in the hospital revealed a sensitivity of 99.8% (953/955), but only a specificity of 2.9% (3/104; threshold 0.5). Predicting survival until discharge from the hospital revealed a sensitivity of 99% (103/104), but only a specificity of 8% (72/955; threshold 0.99). A receiver operating characteristic curve yielded an area under the curve of 0.795 (0.751-0.839) at a confidence interval of 95%. CONCLUSION: For out-of-hospital patients with cardiac arrest, parameters documented in the field did not allow accurate prediction of hospital survival.

Oscillation frequency of skin microvascular blood flow is associated with mortality in critically ill patients

Background:  Microcirculatory dysfunction has been hypothesized to play a key role in the pathophysiology of multiple organ failure and, consequently, patient outcome. The objective of this study was to investigate the differences in reactive hyperemia response and oscillation frequency in surviving and non‐surviving patients with multiple organ dysfunction syndrome.

Ultrasound-guided regional anesthesia for carotid endarterectomy induces early hemodynamic and stress hormone changes.

OBJECTIVE Locoregional anesthesia is an effective method for evaluating cerebral function during carotid endarterectomy (CEA). Landmark-guided regional anesthesia (RA) is currently used for CEA and can provoke substantial perioperative hypertension. Ultrasound-guided RA (US-RA) is a new method for performing RA in CEA; however, the effect on sympathetic activity and blood pressure is uncertain. This study assessed early sympathetic activity during CEA in US-RA compared with general anesthesia (GA). METHODS Patients were prospectively randomized to receive US-RA (n = 32) or GA (n = 28) for CEA. The primary end point was the change in systolic arterial blood pressure after induction of anesthesia (just before starting surgery) comparing US-RA with GA. We also recorded heart rate and analyzed concentrations of plasma blood hormones, including cortisol, metanephrine, and normetanephrine at five different times. Creatinine kinase, troponin I, and N-terminal pro-B-type natriuretic peptide were analyzed to detect potential changes in cardiac biomarkers during the procedure. RESULTS Systolic arterial blood pressure (mean ± standard deviation) increased significantly in US-RA patients compared with GA patients even before surgery was initiated (180 ± 26 mm Hg vs 109 ± 24 mm Hg; P < .001), then remained elevated during the entire surgery and returned to baseline values 1 hour after admission to the postoperative anesthesia care unit. Heart rate (US-RA: 78 ± 16 beats/min, GA: 52 ± 12 beats/min; P < .001) and cortisol levels (US-RA: 155 ± 97 μg/L, GA: 99 ± 43 μg/L; P = .006) were also significantly higher in the US-RA group after induction of anesthesia. Other values did not differ. CONCLUSIONS The US-RA technique for CEA induces temporary intraoperative hypertension and an increase in stress hormone levels. Nevertheless, US-RA is a feasible, effective, and safe form of locoregional for CEA that enables targeted placement of low volumes of local anesthesia under direct visualization.

Cutaneous Microvascular Blood Flow and Reactivity in Hypoxia

As is known, hypoxia leads to an increase in microcirculatory blood flow of the skin in healthy volunteers. In this pilot study, we investigated microcirculatory blood flow and reactive hyperemia of the skin in healthy subjects in normobaric hypoxia. Furthermore, we examined differences in microcirculation between hypoxic subjects with and without short-term acclimatization, whether or not skin microvasculature can acclimatize. Fourty-six healthy persons were randomly allocated to either short-term acclimatization using intermittent hypoxia for 1 h over 7 days at an FiO2 0.126 (treatment, n = 23) or sham short-term acclimatization for 1 h over 7 days at an FiO2 0.209 (control, n = 23). Measurements were taken in normoxia and at 360 and 720 min during hypoxia (FiO2 0.126). Microcirculatory cutaneous blood flow was assessed with a laser Doppler flowmeter on the forearm. Reactive hyperemia was induced by an ischemic stimulus. Measurements included furthermore hemodynamics, blood gas analyses and blood lactate. Microcirculatory blood flow increased progressively during hypoxia (12.3 ± 7.1–19.0 ± 8.1 perfusion units; p = 0.0002) in all subjects. The magnitude of the reactive hyperemia was diminished during hypoxia (58.2 ± 14.5–40.3 ± 27.4 perfusion units; p = 0.0003). Short-term acclimatization had no effect on microcirculatory blood flow. When testing for a hyperemic response of the skins microcirculation we found a diminished signal in hypoxia, indicative for a compromised auto-regulative circulatory capacity. Furthermore, hypoxic short-term acclimatization did not affect cutaneous microcirculatory blood flow. Seemingly, circulation of the skin was unable to acclimatize using a week-long short-term acclimatization protocol. A potential limitation of our study may be the 7 days between acclimatization and the experimental test run. However, there is evidence that the hypoxic ventilatory response, an indicator of acclimatization, is increased for 1 week after short-term acclimatization. Then again, 1 week is what one needs to get from home to a location at significant altitude.

The impact of endotoxin on jejunal tissue oxygenation

We examined the effects of systemic ETX on jejunal mucoal microcirculatory parameters in anesthetized pigs.