New postoperative pain instrument for toddlers-Secondary analysis of prospectively collected assessments after tonsil surgery.

BACKGROUND: The Children's and Infant's Postoperative Pain Scale (CHIPPS) and the German version of the Parent's Postoperative Pain Measure (PPPM-D) are used to assess postoperative pain intensity in preschool children. However, they have shown low concordance in previous prospective studies on quality improvement. AIMS: Our secondary analysis aimed to estimate the association strength between the pain score items and indication for rescue medication defined as CHIPPS ≥4 and/or PPPD-D ≥ 6. Thus, we intended to create a further developed pain instrument with fewer variables for easier routine use. METHODS: We analyzed 1067 pain intensity assessments of hospitalized children for the development of our novel tool in two steps using modern statistical and machine-learning methods: (1) Boruta variable selection to analyze the association strength between CHIPPS score, PPPM-D items, age, weight, and elapsed time after surgery, including their interactions and pattern stability, and the binary outcome (analgesics required yes/no). (2) Symbolic regression to generate a short formula with the least number of variables and highest accuracy for rescue medication indication. RESULTS: Additional analgesics were required in 19.96% of pain intensity assessments, whereby the PPPM-D showed higher variance than CHIPPS. Boruta identified PPPM-D score, CHIPPS score, 9 of the 15 PPPM-D variables, and time of assessment as associated with the indication for RM. Symbolic regression revealed that additional analgesics are required if CHIPPS is ≥4 OR PPPM-D item "less energy than usual" AND one of the items "more easily cry" or "more groan/moan" are answered with "yes." These PPPM-D items were not redundant and showed nonlinear course over time. The cross-validated accuracy for this assessment tool was 94.94%. CONCLUSIONS: The new instrument is easy to use and may improve postoperative pain intensity assessment in children. However, it requires prospective validation in a new cohort.

[Transfer of a cockpit strategy to anesthesiology : Clinical example: introduction of canned decisions to solve cannot intubate cannot oxygenate situations]. / Übertragung einer "Cockpit-Strategie" in die Anästhesie : Klinisches Beispiel: Einführung von "canned decisions" zur Lösung von Atemwegsnotfällen.

BACKGROUND: Safety strategies in civil aviation are well-established. The authors present a possible structure for induction of anesthesia, which includes elements of the so-called cockpit strategy. The objective is to reduce anesthesia-related mortality caused by the unexpected difficult airway through early detection and solution of cannot intubate cannot oxygenate (CICO) situations. METHODS: After approval by the responsible ethics committee, a prospective pilot study was conducted to analyze the process quality of uncomplicated induction of anesthesia on a simulator using audiovisual recording. An evaluation list with 44 items was created, which met the following requirements: items were dichotomous, accessible to an audiovisual evaluation and according to current scientific consensus should be considered during induction of anesthesia. Standard induction of anesthesia was supplemented by several crew resource management elements (cockpit strategy). Two canned decisions (CD, CD 1: end tidal CO2, etCO2 < 10 mm Hg, CD 2: SpO2 < 80%) signaled the emergency of an unexpected difficult airway and CICO with emergency coniotomy. This concept was repetitively trained and transferred to the daily routine. After 6 months the process quality was re-evaluated in simulated scenarios. In order to review whether the effect of the cockpit strategy with the CD can contribute to solving the CICO situation, all emergency coniotomies carried out in this clinic between 2010 and 2016 were retrospectively analyzed. RESULTS: The cockpit strategy significantly improved the process quality during the simulated induction of anesthesia (78% vs. 36% items fulfilled), while the duration of induction was reduced by 36%. In the subsequent 6­year study period, 7 CICO situations with emergency coniotomy occurred. All teams performed in accordance with the algorithm and with respect to the CDs. No patient suffered from hypoxia or any other damage. CONCLUSION: The transfer and implementation of a cockpit strategy in anesthesiology for improvement of patient safety is possible. The acceptance of the aviation safety strategy in medicine is a necessary prerequisite. A profound training in technical and non-technical skills and regular team training to solve CICO situations must be an integral part of advanced training in anesthesiology.

Surgeons' exposure to sevoflurane during paediatric adenoidectomy: a comparison of three airway devices.

Although sevoflurane is commonly used in anaesthesia, a threshold value for maximum exposure to personnel does not exist and although anaesthetists are aware of the problem, surgeons rarely focus on it. We used a photo-acoustic infrared device to measure the exposure of surgeons to sevoflurane during paediatric adenoidectomies. Sixty children were randomly allocated to laryngeal mask, cuffed tracheal tube or uncuffed tracheal tube. The average mean (maximum) sevoflurane concentrations within the surgeons' operating area were 1.05 (10.05) ppm in the laryngeal mask group, 0.33 (1.44) ppm in the cuffed tracheal tube group and 1.79 (18.02) ppm in the uncuffed tracheal tube group, (p < 0.001), laryngeal mask and cuffed tracheal tube groups vs. uncuffed tube group. The presence of sevoflurane was noticed by surgeons in 20% of cases but there were no differences between the groups (p = 0.193). Surgical and anaesthetic complications were similar in all three groups. We conclude that sevoflurane can be safely used during adenoidectomies with all three airway devices, but in order to minimise sevoflurane peak concentrations, cuffed tracheal tubes are preferred.

[Concept for allocation of acute stroke patients: evaluation of the quality of diagnosis reached by the emergency medical services of Münster]. / Zuweisungskonzept bei akutem Schlaganfall : Untersuchung der rettungsdienstlichen Diagnosequalität in der Stadt Münster.

BACKGROUND: Acute stroke is a time- and expertise-critical emergency. An immediate and correct diagnosis by emergency medical services (EMS) in the prehospital phase and patient transfer to the nearest adequate hospital with a stroke unit is required for early treatment of acute stroke. PATIENTS AND METHODS: We evaluated all patients who were admitted by the EMS of Münster to one of the two stroke units in the town between October 2008 and December 2010 with a diagnosis of acute stroke. Furthermore all patients were critically analyzed who were admitted without a diagnosis of acute stroke by the EMS but nonetheless had a stroke and the correct diagnosis was not found until examination in the neurological department. RESULTS: We analyzed 615 patients who were admitted to the stroke units with the diagnosis of acute stroke. In 561 cases (91%) this diagnosis could be confirmed, but in 54 patients (9%) the diagnosis by the EMS was incorrect. Epileptic seizure was the most frequent false-positive diagnosis in this group of patients (39%; n = 21). Although the acute symptoms were caused by a stroke, the correct diagnosis was not defined by the EMS in 127 patients. This accounted for 18% of all patients admitted to the emergency departments by the EMS where ultimately a stroke was diagnosed. In 24% of these cases (n = 30) the emergency doctor missed the correct diagnosis, which meant 4% of all patients admitted by the EMS, finally diagnosed with an acute stroke. In all other cases in the group with a false-negative diagnosis (76% or 97 patients) an emergency doctor was not involved in the referral by the EMS. CONCLUSION: Emergency medical services should be involved in the establishment of admission programs for acute stroke patients to provide the fastest means of transportation to a stroke unit. Coma, symptoms of posterior cerebral circulation and epileptic seizures cause difficulties in ensuring an immediate and correct diagnosis. Sending an emergency doctor to the scene increases diagnostic certainty which is essential to initiate early treatment.

[Do sociodemographic factors influence emergency medical missions? : analysis in the City of Münster]. / Beeinflussen soziodemografische Faktoren Notarzteinsätze? : Analyse in der Stadt Münster.

BACKGROUND: Demographic development and changes in healthcare utilization have led to a rising number of calls for emergency services. In Germany life-threatening situations are responded by physician-staffed ambulances in a 2-tier system whereas paramedic-staffed ambulances are dispatched in non-life-threatening emergencies. A nationwide protocol guides dispatchers in triage decisions. In the years 1999 to 2009 a continuous rise in the number of calls for a physician-staffed ambulance in Münster was recorded. The degree of healthcare utilization according to socioeconomic status and age structure was retrospectively examined. METHODS: For the year 2006 all emergency calls in the City of Münster responded to by physician-staffed ambulances were analyzed. Each call was assigned to 1 of the 45 urban districts. The local incidence of emergency calls (calls/100 residents/year) was determined and compared to the socioeconomic status which was defined as the percentage of welfare and unemployment benefit recipients per district. Patient condition was assessed by the Munich National Advisory Committee for Aeronautics (M-NACA) score. This scoring system allows calls to be allocated to either life-threatening conditions or non-life-threatening conditions by objective vital parameters. The age structure of the emergency callers was also examined. RESULTS: Urban districts with a low socioeconomic status showed a higher incidence of emergency calls requiring physician-staffed ambulance responses than districts with a high socioeconomic status. Measured by the M-NACA scoring system, the fraction of life-threatening emergencies among all calls proved to be equal to districts with a high socioeconomic status. A correlation between elderly patients and increasing numbers of life-threatening emergencies was found. CONCLUSIONS: A low socioeconomic status of an urban district will result in more ambulance responses. However, the proportion of life-threatening emergencies is equal to districts with a high socioeconomic status. Thus, the greater need for physician-staffed ambulance responses matches clinical needs and legitimates current resource use in a 2-tier ambulance system. Indications for the abuse of physician-staffed ambulances were not found. Considering an aging population the number of emergency calls will rise in the future.

The influence of labor epidural analgesia on maternal, uteroplacental and fetoplacental hemodynamics in normotensive parturients: a prospective observational study.

BACKGROUND: Epidural analgesia provides sufficient analgesia during labor but can cause hypotension despite various prophylactic measures. We studied its effects on pre-placental, fetoplacental, and fetal hemodynamics using Doppler ultrasound. The primary endpoint was the pulsatility index of the umbilical artery at 30 min after establishing epidural analgesia. Secondary endpoints included maternal blood pressures and neonatal outcome data. METHODS: We included healthy parturients at a cervical dilation ≥2 cm, with or without a request for epidural analgesia (n=32 per group). Ultrasound studies of the uterine arteries, umbilical artery and fetal middle cerebral artery were performed before insertion of the epidural catheter, and 30, 60 and 90 min after; the same time-points were assessed in the non-epidural control group. Maternal blood pressure was measured by a continuous non-invasive arterial pressure monitor. RESULTS: Ultrasound studies detected no significant differences in pulsatility indices over time in any blood vessel. In contrast to the control group, maternal blood pressures were significantly lower for all measures after the onset of analgesia compared with baseline values (mean systolic pressure decreased from 132.7 ±â€¯15.9 mmHg to 123.1 ±â€¯14.4 mmHg at 30 min, P=0.003). The mean pH value of the umbilical arterial blood was 7.29 (±0.06) in the epidural group versus 7.31 (±0.08) in the control group (P=0.33). The median Apgar score at 5 min was 10 in both groups. CONCLUSIONS: Pre-placental, fetoplacental and fetal hemodynamics remained stable despite a statistically significant decrease in maternal blood pressure in laboring parturients receiving epidural analgesia.

[Chest compression quality : Can feedback technology help?]. / Thoraxkompressionsqualität : Hilft Feedback-Technologie?

BACKGROUND: The outcome of cardiopulmonary resuscitation (CPR) depends on the quality of chest compressions. Current European Resuscitation Council (ERC) guidelines promote the development of feedback systems. However, no studies presenting satisfactory results of feedback use have been published. METHODS: A total of 60 patients with cardiac arrest (> or =18 years of age) received resuscitation attempts using an automated external defibrillator (AED) with real-time feedback by the ambulance service of the City of Münster. The frequency of chest compressions, no-flow time (NFT) and depth of chest compressions were analyzed for the first three cycles of CPR and compared to the ERC guidelines 2005. RESULTS: Chest compression frequency did not differ significantly from the ideal as set out in the guidelines. Analysis of NFTs showed significantly longer NFT for the first cycle but NFT for the second and third cycles did not differ significantly from the ideal. The target depth of 4-5 cm was achieved in 80% of all chest compressions in the first 3 cycles. CONCLUSION: With the AED real-time feedback technology used in this study standardized performance of chest compressions could be maintained in a professional ambulance service. Implementation of a feedback system requires training of ambulance staff.

Ventral recumbency is crucial for fast and safe orotracheal intubation in laboratory swine.

The aim of this study was to find the fastest, easiest and safest method of achieving orotracheal intubation for general anaesthesia in laboratory pigs. Twenty-one Yorkshire x Landrace crossbreed male castrated pigs (32.9 +/- 4.8 kg) were investigated. Dorsal and ventral recumbency are the alternatives most frequently described for animal positioning during intubation procedures. Based on standardized induction of general anaesthesia using pentobarbital and remifentanil, the dorsoventral and ventrodorsal positions were compared with regard to the time needed, changes in oxygenation and circulatory response. Positioning was found to be crucial for fast orotracheal intubation. The time required for safe intubation is significantly shorter with the ventrodorsal position (17.3 s) in comparison with the dorsoventral position (58.4 s; P < 0.001). Hypoxia did not occur in either group. A significant drop in systolic blood pressure was observed in both groups. Diastolic and mean arterial pressures were not influenced by intubation. A significant increase in heart rate was observed in pigs intubated in ventral recumbency, but not after intubation in the dorsal position. Preoxygenation before intubation is vitally important for preventing hypoxia. With regard to clinical practice, the haemodynamic changes observed in this investigation do not appear to be relevant, as the mean arterial pressure was not altered and heart rates only increased moderately. It may be concluded that the ventrodorsal position can be recommended for orotracheal intubation in pigs as the first choice for providing a smooth and fast airway.

Teaching resuscitation in schools: annual tuition by trained teachers is effective starting at age 10. A four-year prospective cohort study.

AIMS: Evaluation of school pupils' resuscitation performance after different types of training relative to the effects of training frequency (annually vs. biannually), starting age (10 vs. 13 years) and facilitator (emergency physician vs. teacher). METHODS: Prospective longitudinal study investigating 433 pupils in training and control groups. Outcome criteria were chest compression depth, compression frequency, ventilation volume, ventilation frequency, self-image and theoretical knowledge. In the training groups, 251 pupils received training annually or biannually either from emergency physicians or CPR-trained teachers. The control group without any training consisted of 182 pupils. RESULTS: Improvements in training vs. control groups were observed in chest compression depth (38 vs. 24 mm), compression frequency (74 vs. 42 min(-1)), ventilation volume (734 ml vs. 21 ml) and ventilation frequency (9/min vs. 0/min). Numbers of correct answers in a written test improved by 20%, vs. 5% in the control group. Pupils starting at age 10 showed practical skills equivalent to those starting at age 13. Theoretical knowledge was better in older pupils. Self-confidence grew in the training groups. Neither more frequent training nor training by emergency physicians led to better performance among the pupils. CONCLUSIONS: Pupils starting at age 10 are able to learn cardiopulmonary resuscitation with one annual training course only. After a 60-min CPR-training update, teachers are able to provide courses successfully. Early training reduces anxieties about making mistakes and markedly increases participants' willingness to help. Courses almost doubled the confidence of pupils that what they had learned would enable them to save lives.

[Value of adjuvant physiotherapy in postoperative pain management]. / Stellenwert der physikalischen Therapie und Physiotherapie in der postoperativen Schmerztherapie.

In times of limited financial and human resources the application of adjuvant physiotherapy postoperatively in orthopaedic patients requires reevaluation. In the early postoperative course physiotherapy improves the patients' mobility. However, it is not able to reduce the need for pain medication. It is intended to minimize complications and to mobilize and motivate the patients early. In contrast, massages are of minor importance in the immediate postoperative course and are applied only in a few selected cases. Cryotherapy plays a major role especially after shoulder and knee surgery. On the other hand, transcutaneous electrical nerve stimulation (TENS) and acupuncture are applied only in selected patients after orthopaedic surgery, e.g., after limb amputation.

Perivascular axillary brachial plexus block and patient positioning: the influence of a lateral, head-down position.

The aim of this study was to examine the effect of a 20 degrees Trendelenburg position on the blockade of nerves that exit the brachial plexus proximally in patients undergoing single-injection axillary brachial plexus block. After a pilot study of eight cadavers suggested that a head-down and lateral position would encourage the proximal spread of local anaesthetic, 72 patients undergoing elective surgery were divided into two equal groups: a Supine group and a Modified Position group (lateral position, 20 degrees head-down tilt). Patients were left in the allocated position for 30 min after an axillary block had been performed with alkalinised mepivacaine 1% 49.5 ml. Sensory and motor blockade evaluation showed that there was a significantly higher proportion of axillary nerve (76% vs. 0%, p < 0.001), thoracodorsal nerve (86% vs. 0%, p < 0.001) and subscapular nerve (89% vs. 0%, p < 0.001) blockade in the Modified Position group. Sensory block of the radial nerve was also improved by the modified position (100% vs. 86%, p < 0.05).

[Corrective osteotomy of the humerus using perivascular axillary anesthesia according to Weber in a patient suffering from McCune-Albright syndrome]. / Oberarmkorrekturosteotomie bei einem Patienten mit McCune-Albright-Syndrom unter perivaskulärer axillärer Plexusanästhesie nach Weber.

We report on a 20-year-old patient with McCune-Albright syndrome suffering from global respiratory insufficiency who required continuous mask ventilation and where intubation had to be avoided. Perivascular axillary anesthesia according to Weber was performed for a double corrective osteotomy of the humerus. During plexus anesthesia the patient was positioned on the non-anesthesized side in a 15 degrees Trendelenburg position. An extension of analgesia was observed up to the complete upper arm region. Using the modified positioning an extension of brachial plexus anesthesia is possible.

[Cladismus and a 'historical' turn in the study of functional adaptation. A critical commentary on Rehkämper]. / Cladismus und eine 'historische' Wende im Studium funktioneller Anpassungen. Ein kritischer Kommentar zu Rehkämper.

In a recently published article, Gert Rehkämper takes a critical stance towards cladistic influences on modern comparative morphology. He singles out as culprits a pre-darwinian notion of homology, a neglect of functional thinking and a misunderstanding of the principle of actualism. Furthermore, 'history' should not be used as an explanatory principle. In contrast, I argue that most central notions in evolutionary biology carry a pre-darwinian heritage, especially the term 'adaptation', without compromising their usefulness in contemporary debates. With the advent of new techniques of phylogenetic reconstructions and comparative analyses, 'history' has become a powerful and quantitative explanatory resource.

Optimal stopover decisions under wind influence: the effects of correlated winds.

Wind speed and direction have a significant effect on a flying bird's ground speed. Migrants are therefore expected to be sensitive to wind conditions and this should have consequences for optimal strategies of stopover and refuelling. Based on an earlier model of time-minimizing migration which includes wind condition, we investigate the consequences of the temporal correlation of wind conditions. Day-to-day changes in wind conditions are modelled with a two-state Markov process and an expression for the expected speed of migration is derived. The policy of the migrants is described by two parameters: a day t(g) when the birds start to leave whenever favourable conditions occur and a later day t(b)when they leave even in unfavourable winds. The model predicts that in most cases departures should be close to the date which is predicted by a wind-free deterministic model and that the birds should never leave without wind assistance. Only if the probability that the condition remains the same on the following day is close to 1 should the birds leave even in unfavourable conditions shortly after the deterministic optimal date. If the transition matrix is highly asymmetrical, i.e. if it is very probable that unfavourable conditions remain and that favourable conditions will change into unfavourable, then the birds are predicted to start using good winds several days before the deterministic optimal date. An analysis of six years of wind data from two sites in Sweden shows that wind directions on successive days are in fact correlated in all years.

Intermolecular interactions involved in solute retention on carbon media in reversed-phase high-performance liquid chromatography.

Carbon adsorbents for RPLC separations are greatly underutilized due to the poor chromatographic properties of the earliest commercially available materials and our limited understanding of solute interactions with the solid surface. Previously, we reported on the properties of a carbon surface prepared by vapor deposition on porous zirconia microspheres. The resulting material is a new type of carbon sorbent with considerably improved chromatographic properties. Here we present a fundamental study of the intermolecular interactions influencing solute retention on these novel carbon phases under RPLC conditions. Retention on seven unique carbon phases has been correlated with solute descriptors of dispersion, dipolarity/polarizability, and hydrogen bond basicity through the use of linear solvation energy relationships (LSERs). In stark contrast, conventional bonded phases do not show the large contribution from dipolarity/ polarizability, that is observed on these types of carbon. The presence of this interaction indicates a distinct difference between carbon and conventional bonded RPLC phases. Other results suggest that solvent sorption plays a significant role in controlling solute retention on carbon. In addition, we investigated the temperature dependence of retention on carbon and found typical RPLC-like behavior.

Recovery from myocardial stunning is faster with desflurane compared with propofol in chronically instrumented dogs.

Volatile anesthetics exert a protective role in myocardial ischemia. An increase in sympathetic tone might exert deleterious effects on the ischemic myocardium. The use of the volatile anesthetic desflurane in myocardial ischemia is controversial because of its sympathetic activation. We compared propofol and desflurane on myocardial stunning in chronically instrumented dogs. Mongrel dogs (n = 8) were chronically instrumented for measurement of heart rate, left atrial, aortic, and left ventricular pressure, rate of rise of left ventricular pressure, and myocardial wall-thickening fraction (WTF). An occluder around the left anterior descending artery (LAD) allowed the induction of reversible LAD-ischemia. Two experiments were performed in a cross-over fashion on separate days: 1) Induction of 10 min of LAD-ischemia during desflurane anesthesia and 2) Induction of 10 min of LAD-ischemia during propofol anesthesia. Both anesthetics were discontinued immediately after completion of ischemia. WTF was measured at predetermined time points until complete recovery from ischemic dysfunction occurred. Both anesthetics caused a significant decrease of WTF in the LAD-perfused myocardium. LAD-ischemia led to a further significant decrease of LAD-WTF in both groups. During the first 3 h of reperfusion, WTF was significantly larger in the desflurane group. Mean arterial pressure and heart rate were greater during ischemia and the first 10 min of reperfusion in the desflurane group compared with the propofol group. Recovery from myocardial stunning in dogs was faster when desflurane was used at the time of ischemia as compared with propofol anesthesia. The mechanism for this difference is unclear, but sympathetic activation by desflurane was not a limiting factor for ischemic tolerance in chronically instrumented dogs.

Thoracic epidural anesthesia does not affect functional recovery from myocardial stunning in sevoflurane-anesthetized dogs.

OBJECTIVE: A beneficial effect of thoracic epidural anesthesia (TEA) on recovery from myocardial stunning was previously shown in awake dogs. The aim of this study was to investigate the effects of TEA on recovery from myocardial stunning in sevoflurane-anesthetized dogs. DESIGN: Randomized animal study. SETTING: Animal laboratory of a university hospital. PARTICIPANTS: Chronically instrumented mongrel dogs. INTERVENTIONS: Six dogs were chronically instrumented for measurement of hemodynamics and myocardial wall thickening fraction (WTF). The following experiments were performed on separate days in a crossover fashion: (1) 10 minutes of ischemia of the left anterior descending (LAD) coronary artery during sevoflurane anesthesia without TEA and (2) 10 minutes of ischemia during sevoflurane anesthesia with TEA. MEASUREMENTS AND MAIN RESULTS: WTF was measured awake (baseline) and at predetermined time points until complete recovery of myocardial function occurred. Induction of anesthesia led to a decrease of WTF compared with baseline. Induction of ischemia led to a further decrease of WTF to negative values, which returned to positive values within the first minute of reperfusion. There were no differences between the two experimental conditions at any of the time points measured. In awake dogs, TEA improved the recovery from myocardial stunning compared with the control experiment. There was no difference between conscious dogs with TEA or sevoflurane-anesthetized dogs with or without TEA. CONCLUSION: TEA has no additional protective effect on the recovery of WTF during sevoflurane anesthesia.

Clonidine improves recovery from myocardial stunning in conscious chronically instrumented dogs.

UNLABELLED: Clonidine, an alpha2-adrenergic agonist, has been widely used in anesthesia because of its sedative, analgesic, sympatholytic, and specific hemodynamic effects. The use of clonidine in myocardial ischemia is controversial because of its bradycardic and hypotensive effects. In the present study, we tested the hypothesis that clonidine improves recovery from myocardial stunning in conscious dogs. Seven dogs were chronically instrumented to allow measurement of left atrial pressure (LAP), aortic blood pressure (ABP), left ventricular pressure (LVP), maximal rate of increase of LVP (LVdP/dtmax), and myocardial wall thickening fraction (WTF). The myocardial blood flow was measured using colored microspheres. To compensate for any potential interaction between the two ischemic episodes, experiments were performed on separate days in a cross-over fashion (four animals underwent Condition 1, and three underwent Condition 2 as their first experiment). The ischemic episodes involved 1) 10 min of ischemia of the left anterior descending (LAD) coronary artery without any intervention, and 2) 10 min of LAD ischemia 30 min after 10 microg/kg iv clonidine. WTF was measured before the induction of ischemia or the application of clonidine (baseline) and at predetermined time points until complete recovery of myocardial function. WTF recovered faster during the first 2 h of reperfusion when clonidine was administered. The increase in plasma epinephrine was attenuated by clonidine during ischemia, but there was no change during reperfusion. The increase of plasma norepinephrine levels was attenuated during ischemia and reperfusion. The hemodynamic effects of clonidine did not depress myocardial perfusion or impair myocardial function. IMPLICATIONS: In this study, we investigated the effects of IV clonidine on myocardial stunning in chronically instrumented dogs. Clonidine improved the recovery from myocardial stunning and attenuated increases in catecholamine plasma levels.

Limited upper thoracic epidural block and splanchnic perfusion in dogs.

UNLABELLED: Epidural blockade leads to a sympathetic block in affected segments and an increase of sympathetic out-flow from various unblocked segments. A limited upper thoracic epidural block (LUTEB) is used during coronary artery surgery affecting the cardiac sympathetic fibers cephalad to the fifth thoracic segment. This block does not extend to the sympathetic fibers innervating the gastrointestinal organs. A LUTEB may lead to an increase of sympathetic activity in the unaffected splanchnic sympathetic segments and the decrease in splanchnic blood flow may contribute to gastrointestinal ischemia after cardiac surgery. We tested the hypothesis that a LUTEB decreases splanchnic perfusion in anesthetized dogs. Thirteen dogs were chronically instrumented with aortic and left atrial catheters, which were used for pressure measurement, as well as injection and withdrawal of reference samples. Thoracic epidural catheters were placed under general anesthesia the day before the experiment. Splanchnic blood flow was determined by using colored microspheres. Induction of a LUTEB did not change general hemodynamics in awake dogs. Propofol anesthesia induced an increase in heart rate that was abolished after LUTEB. LUTEB also decreased mean arterial pressure during propofol anesthesia. We conclude that thoracic epidural anesthesia had no effect on splanchnic blood flow. In propofol anesthetized animals, liver blood flow was increased compared with awake animals; however, it did not change after induction of LUTEB. IMPLICATIONS: A sympathetic block in certain segments leads to increased sympathetic output in unblocked segments. For an upper thoracic epidural block, this might lead to impaired splanchnic perfusion. In awake and propofol-anesthetized, chronically instrumented dogs, however, a limited upper thoracic epidural blockade had no compromising effect on gastrointestinal perfusion.