The Greek e-journal of Perioperative Medicine

3-6

Authors: Aslanidis T

Editorial

26-36

Authors: Papagiannopoulou P, Ntritsou V , Pistofidou K , Mademli A , Stefanovits D , Isaakidis A, Kostoglou Ch, Zachariadou Ch.

There are various formulas and algorithms for the prediction of body weight and appropriate ETT size, in pediatric patients. Body Weight estimation is of paramount importance in pediatrics, especially in emergencies. Predicting the appropriate size of the endotracheal tube saves time, money and reduces complications. The goal of this study was to evaluate the validity of two commonly used formulas for predicting the body weight and the size of the appropriate endotracheal tube, both based on age.353 consecutive pediatric surgical patients aged 2 to 12 years, who required general anesthesia and oral endotracheal intubation were included in this study. Patients were stratified according to their age in two groups: group 2-5 (79 children, 2 to 5 years) and group 6-12 (274 children, 6 to 12 years). At the end of surgery an anesthesiologist, who was not involved in the perioperative treatment, recorded the demographic data and also the size and type of the endotracheal tube used. The prediction of Body Weight (BW) was made according to the following formula: 2-5 y.o.: Weight (kg) = (2 x age in years) + 8 and 6-12 y.o.: Weight (kg) = (3 x age in years) + 7. The formula for calculating the size (size= internal diameter=I.D.) of the endotracheal tube (ETT) was: I.D. for cuffed ETT (mm) = (age / 4) + 3.5 and I.D. for uncuffed ETT (mm) = (age / 4) + 4. For all statistical tests p value <0.05 was considered as statistically significant. In all patients as sum and in both age groups, the predicted body weight was significantly (p<0.05) lower than the actual (measured) weight. In group 2-5y.o, 74.7% of patients received cuffed ETT In group 6-12y.o. 100% of patients received cuffed ETT. In group 2-5 y.o, all patients showed a significantly (p<0.05) lower predicted internal diameter of the ETT, either cuffed or uncuffed, compared to ETT ultimately used. In group 6 -12y.o, there was no statistically significant difference between the predicted and the actually used ETT size. The prediction of body weight in children, by the use of the particular formula, led to underestimation. In children aged 2 to 5 years, the application of the inner diameter calculation of the ETT formula also underestimated the appropriate ETT size. It seems that the traditional age-based formulas often fail to predict the correct ETT size in smaller children which probably does not seem to apply to older children.

55-73

Authors: Lolakos K, Veroniki F, Kyparissa M, Fynt anidou B, Papapostolou E, Antonitsis P, Provitsaki Ch, Grosomanidis V

The deficiency of the natural heart pacemaker, the conduction disturbances and the appearance of arrhythmias are common complications after cardiac surgery. Placement of epicardiac electrodes (ventricular, atrial, or both) during cardiac surgery remains common practice, even though few patients will actually need some kind of temporary epicardiac pacing for various periods of time. Temporary epicardiac pacing may be ventricular, atrial or atrioventricular, depending on the specific features of each patient and it aims at preserving the cardiac rhythm, securing the desired heart rate and achieving an acceptable cardiac output. Temporary epicardiac pacing is not without danger, since, under specific circumstances, it may have a negative impact on the hemodynamics of the patient, to the point of circulatory collapse. It may also cause ventricular tachycardia (R on T phenomenon) and cardiac arrhythmias (if pacing is not synchronized to the heart’s natural pacemaker). Ventricular Pacing and Sensing (VVI) is accomplished by the placement of electrodes only on the ventricles, which a priori means a certain degree of hemodynamic compromise, due to the loss of atrial contribution in preserving cardiac output. In certain occasions, this impact may be even more significant. This case report concerns a patient who underwent Coronary Artery Bypass Grafting (CABG) and after placement of the electrodes of temporary epicardiac ventricular pacing he presented significant decrease in systemic arterial pressure and the appearance of cannon A waves on central venous pressure (CVP) tracing every time the pacemaker was triggered. These phenomena, which receded after the disconnection of the pacemaker, consists a case of Pacemaker Syndrome.This problem was solved by adjusting the pacemaker’s frequency at a rate lower than that of the patient’s natural pacemaker.

4-27

Authors: Schizodimos Th , Iasonidou Ch, Soulountsi V , Kapravelos N

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.

39-52

Authors: Aslanidis Th, Chatzis A, Kontos A, Grosomanidis V, Karakoulas K, Chatzisotiriou A

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.

61-74

Authors: Stergiouda Z, Gkiouliava A, Koraki E, Zarzava E, Trikoupi A

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.

3-26

Authors: Schizodimos Th, Iasonidou Ch, Soulountsi V, Kapravelos N

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.

38-59

Authors: Papapostolou E, Kyparissa M, Fyntanidou B , Besi C , Oloktsidou E, Alexiou I, Pezikoglou I , Grosomanidis V

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.

71-77

Authors: Tsetsou A, Karageorgou E, Kontostathis N, Karadimos A

This case report describes the rare occurrence of tetraplegia, caused by conversion disorder, in a patient who received spinal anesthesia for arthroscopic surgery. A 35-year-old female with a history of migraine headaches received spinal anesthesia for arthroscopic left knee surgery. On sensory block examination, she was noted to have a T10 level of blockade. During surgery and45 min after performing spinal anesthesia, patient reported bilateral loss of both sensation and motor function of her upper limbs. Patient was hemodynamic stable with absence of respiratory depression or any alteration of consciousness level. Physical signs and symptoms did not correlate with any known anatomical or neurological patterns. MRI imaging revealed no abnormalities. Psychiatric consultation was performed wherein familial stressor circumstances were identified, leading to diagnosis of conversion disorder.