2017

In cardiac surgery, head-down and head-up positions are used to control cardiac filling pressure and for cardiac exposure. Even though benefits of head positioning are not clear, they can also bring some risks. Understanding physiological consequences of positioning can help avoiding serious adverse events and complications. In this prospective study we investigated the effect of head-down and head-up position upon systemic and cerebral haemodynamics and cerebral oxygenation and their correlation with Bispectral Index (BIS) in CABG patients under general anesthesia before surgical incision. Thirty patients were enrolled in to the study. After induction and before surgical incision blood pressure, heart rate, central venous pressure, cardiac output, stroke volume variation, BIS, cerebral oxygen saturation and middle cerebral artery blood flow rate values of the study patients were measured at neutral, head-down and head-up positions. The significance of the difference in terms of the means between the positions was studied with the repeated measures analysis of variance, while the significance of the difference in terms of the mean values was analyzed with Friedman test. Statistically significant increase were recorded in blood pressure, cardiac output, central venous pressure, cerebral blood flow rate and BIS values in the head-down position. The head-up position was associated with decrease in cardiac output. We demonstrated that both positions are safe for cerebral haemodynamics and oxygenation in ischemic heart patients. We showed that the short term head-down position can improve cardiac function, probably due to increased preload in ischemic heart patients with normal ejection fraction; however, the head-up position can be detrimental for systemic haemodynamic even for a short period.

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Intracranial hypertension (IH) is currently managed in the intensive care unit with a combined medical – surgical approach. Progress in monitoring and in understanding pathophysiological mechanisms of IH could change current management in the intensive care unit, enabling targeted interventions that could ultimately improve outcomes. The prevention of secondary brain damage from raised intracranial pressure (ICP) is the central focus of neurologic intensive care. The primary goal of ICP management is to maintain ICP below 22 mmHg and cerebral pressure perfusion (CPP) above 60 mmHg. Optimization of oxygenation and cerebral blood flow (systolic blood pressure greater than 110 mm Hg) are essential. The use of positive end-expiratory pressure (PEEP) can increase intrathoracic pressure, thereby potentially increasing ICP by impeding venous drainage. Maintenance of euvolemia and strict monitoring of fluid balance are necessary. Several commonly described measures may be effective in reducing raised ICP such as keeping the patient’s head neutral and elevated at 15 to 30° as these optimize venous drainage. Proper muscle relaxation, adequate analgesia and sedation depth could further minimize elevation of ICP by reducing metabolic demand, ventilator asynchrony, venous congestion, and the sympathetic responses of hypertension and tachycardia. Fever increases brain metabolism and should be treated aggressively. Prophylactic antiepileptic medications should be considered only for traumatic brain injury. Dexamethasone and other steroids should not be used for treatment of IH, except in tumor patients. Hyperventilation should be limited to emergency management of life-threatening raised ICP until other methods of managing IH are available as it can acutely and reliably lower ICP and PaCO2. Hyperosmolar therapy is the principal medical management strategy for elevated ICP. Therapeutic strategies involve the use of mannitol or hypertonic saline. Mannitol is often considered the gold-standard therapy for medical management of IH but the preponderance of current evidence suggests that hypertonic saline could be. Failure of other conservative measures to control ICP should prompt consideration of the initiation of pentobarbital infusion. Aggressive strategies, like surgical decompression or hypothermia, carefully tested, have controversial effects on outcome. Decompressive craniectomy is indicated for massive ischemic stroke as it improved the survival rate and Glasgow outcome scale. Placement of an external ventricular drain should be considered in patients with moderately sized ventricles and signs and symptoms of raised ICP.

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Patient care in Intensive Care Units is characterized by high demanding tasks, which leads in daily high workload. The aim of the study is to evaluate the effect of patient’s sedation level to workload for the certain task. It also examines whether workload lowers over time, as an effect of the experience gained by the repetition of the task. NASA- TLX tool was used as workload assessments method during a complex monitoring task in an adult Intensive Care Unit environment. The latter included monitoring and recording of skin conductance variability, noise level, hemodynamic and respiratory parameters were monitored during 4 hour routine in two groups of patients. The group was defined by the sedation level (Ramsay sedation score); otherwise no major differences were spotted in their characteristics. Both raw and weighted data of the NASA-TLX tool were included in the analysis, which was performed with MS Excel 2007 (Microsoft Co, USA) and Rstudio® IDE v.0.99.903 (Rstudio Inc, Boston, MA, USA). Patients’ sedation level did not affect NASA-TLX measured workload. The former was valid both for raw values and weighted data of the subscales of the NASA-TLX tool.  In the second part of the analysis where the raw values were treated as time series data, it was shown that some subscales (Ment, Phys) had a tendency towards lower values, others (e.g. Temp, Ef) had a relative stability and others  (Per) increased over time. The total workload (OW) did not seem to lower over time. While the patient’s sedation level does not affect workload of the specific task, several subscales of the NASA-TLX index do reveal a tendency over time; a fact that may be used as learning curve/ experience assessment for a given task. However, further studies are needed in order to define its future utility.

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Noonan syndrome (NS) is an autosomal dominant disorder characterized by anatomic and pathophysiologic abnormalities.Anesthetic management in these cases has many challenges regarding airway management and cardiovascular stability.We present a case report of a 11-year-old male child who was scheduled for maxillofacial surgery under general anesthesia.

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We report a case of persistent bronchospasm after anesthesia induction. The case refers to an elective surgery of an ulcerous formation in the intergluteal cleft. Bronchospasm is not an unusual event in the immediate intubation period, especially in patients with respiratory disease, but in most cases resolves uneventfully. In this patient, despite thorough treatment in the operation room, ausculatory findings remained unchanged, with progressive worsening of arterial blood gases. After this event, the surgery was postponed and the patient was transferred to the ICU for further management. In this article we describe the steps that were taken in order to manage this adverse event and ensure patient’s safety and successful outcome.

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The first issue of 2017 contains few, but very interesting articles. In their review Shizodimos et all, highlight the details hidden in the available literature about mechanical ventilation in Acute Respiratory Distress Syndrome, which after publication of Berlin definition1, is gaining again more and more interest2.

In the next article, Karveli –Argyriadou challenge the current trend regarding cardiac anesthesia publications by presenting us its track in time. In the era of minimal invasive cardiosurgery, genetic therapy and ultra-fast track cardiac anesthesia protocols, they remind us the course and the moments of its evolution and allow us to “look back in order to realize how much we have progressed”.

Papapostolou et al, focus on the importance of right interpretation of hemodynamic monitoring and present 3 cases of acute intraoperative pulmonary hypertention during cardiac surgery.

The last two articles describe a case on pulmonary embolism after surgery for Adolescent idiopathic scoliosis and a conversion disorder that was presented with tetraplegia post spinal anesthesia.

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Acute respiratory distress syndrome (ARDS) is an acute inflammatory lung injury, associated with increased pulmonary vascular permeability, increased lung weight, and loss of aerated lung tissue. There remains limited information about the epidemiology, recognition, management, and outcomes of patients with the ARDS, but in-hospital mortality is still high for those with moderate and severe ARDS (40.3% and 46.1%, respectively). Mechanical ventilation does not cure ARDS but simply buys time by maintaining a gas exchange sufficient for survival. The guiding principle of mechanical ventilation of ARDS is the new setting is less harmful to the lung structure than the previous one, thus avoiding the ventilator induced lung injury (VILI). Among outcome studies testing different tidal volumes, only the study comparing the two extreme values tested (6 mL/kg versus 12 mL/kg) showed a significant benefit of lower tidal volume. ‘The best positive end expiratory pressure (PEEP)’ does not exist. Recruitment maneuvers (RMs) are helpful in increasing aerated lung volume, which decreases strain and tidal recruitment/derecruitment. There is no definitive evidence regarding the clinical effectiveness of RMs to improve clinical outcomes of ARDS patients, although RMs may decrease the mortality of patients with ARDS without increasing the risk for major adverse events. There is no evidence for a difference between pressure control versus volume control ventilation in terms of physiological outcome or mortality. The effect of respiratory rate on the occurrence of VILI or outcome in ARDS has not been independently studied. Increasing inspiratory time has been suggested to improve oxygenation. Prone position (PP) is a standard practice in clinical treatment of ARDS patients to improve systemic oxygenation to any patient with moderate or severe ARDS as it may confer a statistically significant mortality advantage. There is evidence that neuromusculal blockade by cisatracurium besylate has an outcome benefit in ARDS patients since they improve lung mechanics and lung inflammation. Optimal dosing and monitoring strategies will need to be further studied.

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Cardiac surgery is a specialty with a relatively short history. The difficulties and particularities of Cardiac Surgery made apparent right from the beginning that there was a need forspecialized anesthesiological support. In 1940, Cardiac Surgeons pioneers recognized the role and contribution of cardiac anesthesiologists. In 1945, Blalock thanking his anesthesiologist co-workers Lamont and Harmel in public and mentioned that thanks to their anesthesiological support there “was no death during the first 55 operations”. Russell Brock, in 1949, highlighted the importance of collaboration between cardiac surgeons and cardiac anesthesiologists and mentioned “In this type of surgeries co-operation is necessary. The anesthesiologist plays a vital role and deserves special honor and recognition.” Since the first application of the electrocardiogram to operating theatres in 1950, the introduction of transesophageal echocardiography perioperatively in 1971, until the last decade with the application of coagulation monitoring, the newer data in the management of severe bleeding and the anesthesiological support in brand new minimal invasive techniques, cardiac anesthesiologists have vitally supported the evolution of cardiac surgery. The following text is a historical review describing the contribution of cardiac anesthesia in a continuing effort to improving clinical outcome and enhancing the safety of cardiac surgery.

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Evaluation of monitoring readings, taking into account each patient’s pathology as well as the impact of every medical intervention can guide us to make optimal clinical decisions in the periopeative setting. We present three cases in which clinical decisions concerning the management of acute perioperative pulmonary hypertension were based both on haemodynamic monitoring readings and on each patient’s specific pathology. First case: After anesthesia induction in a patient with severe aortic valve insufficiency, an increase in pulmonary artery pressure was recorded. Infusion of isoprenaline, which has a positive chronotropic effect, decreased diastolic time, diastolic blood flow into the left ventricle and also pulmonary artery pressure. Second case: A patient with severe aortic valve stenosis was found with increased pulmonary artery pressure. Intravenous administration of atenolol (1+1mg) reduced the heart rate and the pulmonary artery pressure. Third case: A 15 year old patient with aortic isthmus rupture underwent open surgical repair with graft interposition. After establishment of one lung ventilation and left thoracotomy, pulmonary artery pressure increased. Pulmonary hypertension was managed successfully by oxygen insufflation to the non-ventilated left lung. In our first patient, heart rate increase reduced diastolic time, which decreased the amount of retrograde blood flow into the left ventricle through the regurgitant aortic valve. In the second patient, the heart rate reduction decreased blood flow velocity through the stenotic aortic valve as well as the pressure gradient between left ventricular chamber and aorta. In both patients, enhanced left ventricular function resulted in a reduction in pulmonary artery pressure. Decrease of the alveolar partial pressure of oxygen (PAO2) is the most important parameter that stimulates hypoxic pulmonary vasoconstriction. Oxygen insufflation increased PAO2, resulting in a decrease in pulmonary artery pressure .Clinical decisions based on haemodynamic monitoring readings resulted in effective management of pulmonary hypertension and in a good patient outcome.

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