The Greek e-journal of Perioperative Medicine

15-36

Authors: Petrou A, Christoforidis S

The tremendous impact of hypoxia on any critical organ, namely the brain and the heart, are well known, at least because of their obvious result. The question asked by many: “For how long can the patient tolerate apnoea?” cannot be answered with certainty for any given patient. The long list of possible problems that may arise during the transport of O2 from the anesthetic circuit to the very last cell of the human organism precludes any possibility of precise calculation. Hypoxia of critical tissues (the brain and the heart) has deleterious pathophysiologic effects on them. The abrupt and intense rise in systemic and pulmonary blood pressure combined with tachycardia, adds an excessive work load (and so an extra ATP deficit) to the myocardium. Thus it can increase morbidity from myocardial ischemia, rupture of aneurysms in the systemic and cerebral circulation, acute heart failure, pulmonary hypertension and failure of the right heart. The severity of these consequences may be augmented by the cellular effects of hypoxia like disruption of cell structure and sensitization to arrhythmias. The Central Nervous System accepts an excessive work load too. It has to fulfill auto regulation requirements: regulation of the perfusion pressure to the brain while systemic blood pressure presents with at least biphasic fluctuation during hypoxia and apnoea, manage the responses of reflex mechanisms, conservation of electrical activity in order to continue its central role as command center and sympathetic and parasympathetic outflow to the heart and other organs in gravely hypoxic conditions, over viewing hormonal and catecholamine discharge etc. All these responsibilities should have to be concluded in a milieu of strenuous efforts to conserve or replace ATP and get rid of the products of anaerobic metabolism. This is obviously a titanic work. It could be more devastating, if all these procedures should be completed in subjects who may already suffer from serious derangements of their physiology like systemic hypertension, coronary artery disease, carotid artery disease, chronic pulmonary disease, diabetes mellitus, intracranial hypertension and cerebral oedema. And it becomes worse, when hypoxia and apnoea ensues in patients, who are trying to conserve homeostasis while suffering from multiple trauma, sepsis or acute respiratory insufficiency. Finally, possibly under the systemic effects of anesthetic agents, cells of critical organs respond to protracted hypoxia with programmed cell death after stressful combat to retain structural and operational integrity. Some anesthetic agents are considered to have protective effects to the brain and the heart against ischemic – reperfusion injury. Unfortunately, we are lacking almost any data on their possible positive or negative effect on hypoxemic hypoxia during apnoea. A few agents have been discovered that could offer in time protection against hypoxia. Even less would be applicable in every day clinical practice, as the cases of difficult airway come up unexpectantly. So what should be done? Apparently we should be able to understand and learn any critical information that has been discovered about the systemic effects of hypoxia and apnoea. And most important, we should make any effort to continuously apply structured and well organized procedures of administering anesthesia in order to minimize the rate of hypoxic accidents and their effect on human tissues that are obviously completely dependant on oxygen.

54-65

Authors: Papagiannopoulou P, Didilis V, Ferdi E, Stam atiou G, Dragoum a nis Ch, Iatrou Ch, Vretzak is G

Cardiac stabilization during “off-pump” coronary revascularization (OPCAB) has been implicated in causing intraoperative hemodynamic disturbances. Stroke volume and cardiac output reductions may alter the ventilation/perfusion ratio in the lungs and compromise the gas exchange. This study was conducted to determine the impact of heart’s stabilization on arterial blood-gas profile in patients undergoing OPCAB surgery. After institutional approval and informed consent, 57 patients undergoing OPCAB procedures were studied. LIMA was anastomosed to LAD in all patients. In 20 patients a second coronary vessel received a graft, while in 5 patients a third vessel was also anastomosed under propofol-remifentanil (TIVA) anesthetic technique. FiO2 was equal to 1. Compression fork-type stabilizer was used. Full hemodynamic profile, mixed venous oxygen saturation, acid base status, end-tidal partial pressure of carbon dioxide and ST-segment changes were monitored before heart’s stabilization (T1 values-baseline), 5 minutes after stabilization (T2 values), before stabilizer’s removal (T3 values) and 10 minutes after stabilizer’s removal (T4 values). Oxygen delivery and consumption, VD/VT and Qs/Qt were calculated. Ventilation was kept unchanged during data collection. Statistical analysis for pairwise comparisons with baseline values (T1) was performed with Dunnett’s two-sided multiple-comparison procedure. Statistical analysis was performed using the t-paired test. A value of p<0.05 was considered statistically significant. During LIMA→LAD grafting (n=57) cardiac stabilization and anastomotic maneuvering caused significant hemodynamic changes. Cardiac output, stroke volume and mixed venous oxygen saturation decreased significantly (4.44 ± 1.0 → 3.43 ± 0.8 L/min, 70.6 ± 15.5 → 52.6 ± 14.2 ml, 83.5 ± 4.7 → 76.5 ± 8.0 % respectively; p<0.001 for all) while systolic, diastolic and mean pulmonary pressure, central venous pressure and capillary wedge pressure increased significantly during stabilizer’s application (T2, T3 values). Calculated O2 delivery and consumption were decreased. PH, bicarbonate and base excess decreased significantly at all times compared to baseline (7.45 ± 0.03 → 7.43 ± 0.03, 23.9 ± 1.44 → 22.9 ± 1.98 mEq/L, 0.06 ± 1.6 → -0.98 ± 1.9 respectively; p<0.001 for all) while arterial partial pressure and end-tidal partial pressure of carbon dioxide decreased at T2, T3 interval and increased at T4. Arterial partial pressure of oxygen increased significantly after stabilizer’s placement (T2, T3 interval) and decreased in stage T4. Qs/Qt was decreased during anastomotic maneuvering. IN OPCAB SURGERY, THE HEMODYNAMIC CHANGES DUE TO the heart’s stabilization caused significant changes in the arterial blood gas profile. The reduction of systemic flow and tissue perfusion led to increased plasma hydrogen ion concentration. Restoration of flow was followed by “wash-out” phenomena. Arterial tension and exhalation of CO2 were primarily influenced by the decreased O2 consumption, the increased VD/VT and the buffering of protons after the stabilizer’s removal. In this study population, the deterioration in gas exchange was minor. Although these changes are not persistent, they may have implications in the intraoperative management of patients with compromised alveolar gas-exchange.

73-79

Authors: Theodosiadis P, Grosomanidis V, Touroutoglou N

Neurolytic celiac plexus block (NCPB) is a useful technique for pain control in patients with intra-abdominal tumors or pain secondary to chronic pancreatitis that does not respond to other therapeutic modalities (not interventional). The anterior approach for NCPB has been considered a relatively safe approach, with a low rate of complications and little risk of neurologic injury secondary to the spread of a neurolytic agent. This is the first national case report of successful NCPB using the anterior approach under CT guidance.

6-26

Authors: Papaioannou V

Acute and prolonged illness seems to result in a variety of different neuroendocrine alterations. During the acute phase of critical illness there is an actively secreting anterior pituitary gland and a peripheral resistance to anabolic hormones. In the chronic phase of critical illness there is a uniformly reduced secretion of anterior pituitary hormones, with the notable exception of cortisol. The main characteristic of these alterations is the ‘wasting’ syndrome. An acute event, such as an infection or emergency surgery in a long-stay ICU patient, is accompanied by mixed acute/chronic endocrine patterns. Wasting syndrome is manifested, among others, with hyperglycemia and insulin resistance, while the severity of this ‘diabetes of stress’ reflects the risk of death. Recently it was shown that preventing these metabolic patterns with insulin infusion improves outcome in critically ill patients. It remains to be demonstrated if other endocrine interventions will accelerate recovery, especially in long-stay patients in ICU.

41-48

Authors: Georgiadou Th, Kostoglou Ch, Kanakoudis F

Acute inflammatory response is the body’s direct response to noxious stimuli or to tissue necrosis. Ischemia-reperfusion lesion is a clinical state of acute inflammation with leucocyte-induced tissue damage. Ischemia promotes an inflammatory response which sensitizes tissues to further damage during reperfusion. Reperfusion activates inflammatory mediators from remote vascular or tissue sites or from the local vascular bed. Reperfusion remains the cornerstone for the repair of ischemic areas. Recently it is emphasized that repeated ischemic episodes of small duration with reperfusion interval periods in between make tissues more resistant to further long-termed ischemia. This is the I.P phenomenon. Many pharmacological agents (such as volatile anesthetics) are capable of inducing I.P. Other measures that can prevent or reduce ischemia-reperfusion injury, are controlled reperfusion, antioxidant, anti-complement and anti-leucocyte therapy.

60-67

Authors: Vasiliadis M , Mitragas A, Konstantinidou A, Markala D, Kaplanis K

Perioperative hypercoagulation in cancer patients is frequently a concern for the anesthesiologist. Ιt is not clarified yet whether the choice of anesthetic technique offers significant advantages for the prevention of postoperative complications. For this purpose, a prospective, randomized clinical trial was conducted. Forty-two female patients with ovarian cancer, undergoing abdominal hysterectomy, were randomized in three groups. In the first group, 19 patients received general anesthesia, in the second group 18 patients received combined anesthesia, in particular general anesthesia with epidural administration of local anesthetic and in the third group 15 patients also received combined anesthesia, but with epidural administration of opioids. The following parameters were measured: Hemoglobin, platelet count, prothrombin time, INR (International Normalised Ratio), activated partial-thomboplastin time, fibrinogen, D-Dimers, antithrombin III, protein C and resistance to activated protein C. Four blood samples were taken: 1st) preoperatively, 2nd) in the Post-Anesthetic Care Unit, 3rd) twenty-four hours and 4th) forty-eight hours postoperatively. No statistical difference was observed among the groups in all parameters. In the second postoperative day, an increase of fibrinogen (p<0.01) and of D-Dimers (p<0.001) was observed. It seems that either general anesthesia or combined anesthesia (general anesthesia with epidural local anesthetics or opioids) influence these certain coagulation parameters in the same manner in cancer patients. An increase of fibrinogen and of D-Dimers was observed in the second postoperative day in the patients of all groups.

75-77

Authors: Vassiliadis MA, Barbetakis ND, Balamoutsos NG

Several techniques have been described for percutaneous internal jugular vein catheterization. Some of them are associated with complications, such as tracheal tube cuff puncture. We describe two cases of this rare but potential devastating complication, after which our patients recovered uneventfully. Despite these unfortunate accidents, we recommend the mentioned technique, but with some consideration. We propose measures concerning angles and directions of needles, as useful aids for further use of this cannulation technique.

85-87

Authors: Papadimos TJ

Medical equipment can interfere with an electrocardiogram (ECG) and mimic a dysrhythmia [1-7]. Unnecessary interventions may occur when artifact is misdiagnosed as ventricular tachycardia (VT) [8,9]. We encountered such an ECG artifact when an orthopaedic shaver was engaged during knee arthroscopy.

25-33

Authors: Skubas N, Fontes M

The pericardial diseases result in cardiovascular perturbations ranging from asymptomatic electrocardiographic findings (in pericarditis of end-stage renal disease) to circulatory shock (in acute hemorrhagic pericardial tamponade). Despite of clinical features that resemble right-, or left-side failure, the clinical management of pericardial pathology may differ significantly from those of ventricular systolic or diastolic dysfunction. Therefore, prompt diagnosis and appropriate medical or surgical therapy is imperative.

60-67

Authors: Soumpasis I, Zhoulqarni F

One of the few areas in clinical medicine which is more affected by advances in engineering technology is cardiac pacing. In about half a century since the first implantation of a pacing system, there has been a significant progress concerning the pacing devices and along with the growing number of new indications for pacing, this will lead to an increasing number of implanted devices over the following years. This fact will raise the possibilities for the new anaesthesiologist to manage a paced patient. Despite the remarkable progress, there is still the chance for adverse effects due to exposure to electromagnetic and mechanical interference. It is necessary to understand the indication for which the device was prescribed and how it is expected to react in such conditions. Another consideration is the knowledge to detect possible device malfunction, and the basic principles of their treatment. However, anaesthesiologists must recognize that this is a very complex and constantly evolving field of technology. It is strongly recommended that they make use of all the resources available to them for advice, regarding perioperative management issues. So that the perioperative management of the patient with cardiac rhythm devices will be beyond the common practice a really challenging experience.

87-92

Authors: Papadopoulos D, Ioannou P, Nikolaidis Ch

In this study we compared the efficacy of three methods of analgesia following total knee arthroplasty (TKA). Fifty-seven patients (n=57), with mean age 70 + 5 and physical status ΑSA I-III, were scheduled for TKA and were randomly allocated in into three groups. Group A patients (n=19) received analgesia by continuous iliac fascia block (CIFB), group B patients (n=19) received continuous epidural analgesia (CEA) and group C patients (n= 19) received intramuscular pethidine at regular time intervals. During the first forty-eight hours after the operation (at 2, 4, 12, 24 and 48 hours) the following parameters were recorded and analysed: severity of pain, supplementary analgesics required and complications occurring for every group of patients. Group A and B patients had significantly better pain relief, compared to group C patients. The need for additional drugs was not statistically significant between groups A and B. More group C patients needed supplementary analgesics, in comparison with groups A and B. Group A had significantly fewer complications, when compared to groups B and C. As a conclusion, the methods of CIFB and CEA following TKA provide significantly better pain relief, compared to intramuscular pethidine administration. CIFB seems to be as treatment of choice for providing the most effective analgesia after TKA, since it provides equally effective analgesia as CEA, has the fewest complications and is the simplest of the three methods, not requiring either nerve stimulation or induction of paresthesia.

26-39

Authors: Skubas N

Ultrasound-based diagnostic techniques are now part of the cardiological patients’ chart, while echocardiography is used more often for intraoperative diagnostic as well, as monitoring practices by the anesthesiologist. This article will address the basic physical principles of the ultrasound waves and describe the interactions of ultrasound waves with tissues that lead to the generation of two-dimensional and Doppler ultrasound images

48-57

Authors: Iatrou Ch

Pain is the sensation associated with injury, and injury produces pain. Pain is nociceptive (“normal”) when it results from the activity of healthy nociceptive afferents aroused by noxious stimuli. The physiology of nociception involves a complex interaction of peripheral and central nervous system structures. Strong and repeated noxious stimuli frequently affect the “pain system” and causing it to become sensitized. This gives rise to “amplified or pathophysiologic” nociceptive pain. The pathophysiology of nociceptive pain shows alterations of normal physiological pathways, giving rise to hyperalgesia, allodynia, and automatic pain. The main thought behind this article is that a better understanding of pain mechanisms will improve the rendering effective pain treatment