Krzysztof Kusza

Microcirculatory responses to hypovolemic shock.

The main role of the microcirculatory network is to allow the exchange of molecules between blood and tissue. Particularly, the exchange of oxygen, carbon dioxide, nutrients, hormones, cytokines, waste products, and heat takes place between circulating blood and parenchymal cells. Adequate blood flow within the microvascular network is an essential prerequisite for normal organ perfusion and function which determines normal hemodynamic conditions of the living organisms. Under shock conditions regardless of the resuscitation undertaken, microcirculatory abnormalities are known to persist long after successful patient resuscitation as assessed by central hemodynamic parameters. These abnormalities may be a major contributing factor to the development of postshock multiorgan dysfunction syndrome. Thus, microcirculatory network may be considered as special vital organ of cardiovascular system which functions to ensure adequate delivery of oxygen to various tissues1 and as a result, becomes a subject of interest to many investigators interested in improvement of hypovolemic shock treatment. The purpose of this review article is to present current insights into the changes in microcirculatory hemodynamics and their responses to hypovolemic conditions relevance to trauma patients. We have excluded discussion of septic shock classified as distributive hypovolemic shock because of its different and complicated pathophysiology described in other previously published articles.2–4

Is the knowledge on tissue microcirculation important for microsurgeon

This review article outlines the importance of knowledge on the hemodynamics of microcirculatory responses during free tissue transfer procedures. Anatomy and pathophysiology of peripheral microcirculation are outlined in the context of its responses during microsurgical procedures submitted to ischemia and reperfusion injury. The factors influencing the patients outcome such as neural, humoral, and muscular regulations and prostoglandins, kinins, nitric oxide actions, and so on are outlined. In addition, otherimportant factors influencing microcirculatory responses are discussed. Thegoal of this review article is to introduce nonsurgical factors independentof the microsurgeons control which, via changes in microcirculatory hemodynamics, may contribute to free flap survival and final patients outcomes. Thus, we hope that this overview of the pathophysiology of tissuemicrocirculation will help microsurgeons to monitor factors beyond control of vessel patency and technical aspects of microvascular anastomosis.

Microcirculatory response to halothane and isoflurane anesthesia

Microcirculatory hemodynamics are often used to monitor tissue and organ survival. This study investigated the effect of halothane and isoflurane anesthesia on peripheral microcirculation using the cremaster muscle during intravital microscopy. Twenty-three Sprague-Dawley rats were studied in four groups. Two groups served as controls and did not undergo flap isolation but did receive halothane (N = 6) or isoflurane (N = 5). After induction with a single dose of intraperitoneal pentobarbital (40 mg per kilogram), rats were ventilated with either 2 minimum alveolar concentration (MAC) halothane or 2 MAC isoflurane. Esophageal temperature, electrocardiography, central venous pressure, mean arterial pressure, and blood gases were measured over 4 hours. In groups receiving surgery with either halothane (N = 6) or isoflurane (N = 6), the cremaster muscle was isolated on the neurovascular pedicle. Microcirculatory responses to both halothane and isoflurane anesthesia were evaluated by measuring red blood cell (RBC) velocity, vascular diameters in arterioles (A1, A2-1, A2-2, and A3) and the main venule (V1), functional capillary perfusion, and leukocytic endothelial interactions in postcapillary venules (rolling, adherent, and transmigrating leukocytes). Hemodynamic variables were compared among all four groups, and microcirculatory variables were compared between the two surgical groups. During isoflurane anesthesia in animals with flaps, significantly higher (p < 0.05) RBC velocities were recorded in arterioles A1 (24.4%), A2-2 (28.2%), and A3 (17.4%). Capillary perfusion was significantly higher in animals with flaps and halothane anesthesia (17.8%; p < 0.05). The number of rolling leukocytes (39.4%) was significantly higher during isoflurane anesthesia in animals with flaps (p < 0.05). Better flow hemodynamics in the peripheral microcirculation were seen during halothane anesthesia, and were confirmed by greater functional capillary perfusion and fewer activated leukocytes. In the isoflurane group, RBC velocity alone cannot serve as an indicator of microcirculatory function.

Harmful effects of invasive animal monitoring on muscle flap microcirculation

In this study, peripheral microcirculatory response to arterial and venous cannulation was studied. Eleven Sprague-Dawley rats were evaluated in two groups. Group I was the control group and received no cannulation (N = 6). After cremaster muscle isolation, the following parameters were evaluated at the microcirculatory level: vessel diameters, red blood cell (RBC) velocities, capillary density, and leukocyte and lymphocyte behavior (rollers, stickers, transmigrating white blood cell [WBC]). In group II, vessel cannulation was performed (N = 5). Before cremaster muscle isolation, the right femoral artery was cannulated for mean arterial blood pressure measurements; the right carotid artery was cannulated for arterial partial oxygen pressure (PaO2), arterial partial carbon dioxide pressure (PaCO2), and pH measurements; and the left jugular vein was cannulated for central venous pressure evaluation. Microcirculatory measurements as in group I were also taken. In the cannulated animals, arterial RBC velocity was 18.1% faster, whereas venous RBC velocity was 15.7% decreased (p < 0.05). In addition, leukocyte activation Increased and was confirmed by a 254.6% rise in rolling leukocytes, a 59.7% increase in rolling lymphocytes, and a 67.2% increase in leukocyte “stickers‘’ (p < 0.05). In group II, functional capillary perfusion was decreased by 44.9%, and 4.8% higher endothelial edema indexes were found (p < 0.05). In conclusion, this study has proven that, despite its clinical importance during vital signs monitoring, cannulation procedures may significantly Impair peripheral microcirculatory hemodynamics. For this reason, cannulation procedures should be designed with caution and should be reported in experimental methods.

Influence of demographic factors, basic blood test parameters and opioid type on propofol pharmacokinetics and pharmacodynamics in ASA I-III patients.

The aim of the study was to examine population pharmacokinetics (PK) and pharmacodynamics (PD) of propofol (CAS 2078-54-8) during total intravenous anesthesia monitored by spectral frequency index (SFx). Twenty-eight patients of ASA physical status I-III (ASA: American Society of Anesthesiologists) scheduled for laparoscopic cholecystectomy were included. In group I an anesthesia was induced with a bolus of propofol (2 mg/kg) and remifentanil (CAS 132875-61-7) (1.0 microg/kg), followed by a continuous infusion of remifentanil. In group II, an alfentanil (CAS 71195-58-9) (10 microg/kg) bolus dose was followed by a continuous infusion of alfentanil. The general anesthetic technique included propofol, opioid and muscle relaxant. During anesthesia, the propofol infusion rate (3-8 mg/kg/h) was adjusted to the SFx value. Venous blood samples were collected from the patients during 240 min after termination of the infusion. A two compartment model was used to describe propofol PK. A standard effect compartment model was used to describe the delay between the effect and the concentration of propofol. The SFx index was linked to the effect site concentrations through a sigmoidal Emax model. The influence of continuous (body weight, age, blood pressure, heart rate and blood oxygenation, serum protein, the erythrocyte count, hemoglobin and hematocrit, serum creatinine and creatinine clearance) and categorical (gender and the type of opioid) covariates on the pharmacokinetic and pharmacodynamic parameters was investigated. PK/PD analysis was performed using NONMEM. All the screened covariates did not influence propofol PK and PD, except of the opioid type. The central compartment volume of propofol was larger in the presence of remifentanil than in the presence of alfentanil.

Intraoperative Fluid Therapy and Pulmonary Complications

The purpose of this study was to evaluate the effects of intraoperative fluid therapy on length of hospital stay and pulmonary complications in patients undergoing spine surgery. A total of 1307 patients were analyzed. Sixteen pulmonary complications were observed. Patients with a higher volume of administered crystalloids, colloids, and total intravenous fluids were more likely to have postoperative respiratory complications: the odds of postoperative respiratory complications increased by 30% with an increase of 1000 mL of crystalloid administered. The best cutoff point for total fluids was 4165 mL, with a sensitivity of 0.8125 and specificity of 0.7171, for postoperative pulmonary complications. A direct correlation existed between fluids and length of stay: patients who received >4165 mL of total fluids had an average length of stay of 3.88±4.66 days vs 2.3±3.9 days for patients who received <4165 mL of total fluids (P<.0001). This study should be considered as hypothesis-generating to design a prospective trial comparing high vs low intraoperative fluid regiments for patients undergoing spine surgery.

Improved quality of surgical field during endoscopic sinus surgery after clonidine premedication—a pilot study

Inadequate surgical field visualization due to intraoperative bleeding during endoscopic sinus surgery (ESS) can cause major complications. The aim of this prospective study was to compare the effect of preoperative administration of clonidine and melatonin on the quality of the surgical field visualization and selected aspects of presurgical premedication.

Hemodynamic Changes and Fluid Shifts After Large-Volume Fluid Infiltration: Results From a Porcine Model

While certain parameters such as blood loss and serum lidocaine levels following liposuction have been well studied, fluid shifts between the intravascular and extravascular space have not. With the advent of large volume liposuction, prudent fluid management has become obligatory. Hence, the reason for our study.To test the impact of large volume infiltration on intercompartmental fluid shifts, we measured urine output and hemodynamic changes in 10 anesthetized female Yorkshire pigs weighing between 50 and 85 kg. Eight pigs were infused with 5 to 10 L of tumescent fluid. Two pigs were anesthetized, received no wetting solution, and served as controls. Hemodynamic variables were recorded before infusion and hourly for 48 hours. Animals were extubated after 4 hours of anesthesia. Plasma volume was measured using Evans Blue Dye, and intravascular fluid shifts were calculated using Foldagers method.Total fluid shift into the intravascular space ranged between 511 and 1036 mL per animal with a mean of 767 mL in the first 3 hours. Higher volumes of fluid infiltration did not lead to fluid overload in the experimental group. Hemodynamic changes were characterized by significant increases in central venous pressure, cardiac output, pulmonary artery pressure, and heart rate consistent with the increase in intravascular volume. Hemodynamic parameters returned to baseline 20 hours following tumescent fluid infiltration.In this porcine model, animals were able to tolerate large fluid challenges delivered by clysis with statistically significant but only modest increases in hemodynamic parameters which gradually returned to baseline within 20 hours.

Comparison of Clonidine and Midazolam Premedication Before Endoscopic Sinus Surgery: Results of Clinical Trial

Objectives Premedication with clonidine has been found to reduce the bleeding during endoscopic sinus surgery (ESS), therefore lowering the risk of surgical complications. Premedication is an essential part of pre-surgical care and can potentially affect magnitude of systemic stress response to a surgical procedure. The aim of this study was to compare the efficacy of premedication with clonidine and midazolam in patients undergoing sinus surgery. Methods Forty-four patients undergoing ESS for chronic sinusitis and polyp removal were enrolled and randomly assigned to receive either oral clonidine or midazolam as a premedication before receiving propofol/remifentanil total intravenous anesthesia. The effect of this premedication choice on anesthetic requirements, intraoperative hemodynamic profile, preoperative anxiety and sedation as well as postoperative pain and shivering were examined in each premedication group. Results Total intraoperative remifentanil requirement was lower in the clonidine group as compared to the midazolam group 503.2±147.0 µg vs. 784.5±283.8 µg, respectively (P<0.001). There was no difference between groups in required induction dose of propofol, level of preoperative anxiety, level of sedation and postoperative shivering. Intraoperative systemic blood pressure and heart rate response had a more favorable profile in patients premedicated with clonidine. Postoperative pain assessed by visual analogue scale for pain was lower in the clonidine group compared with to the midazolam premedication group. Conclusion Premedication with clonidine provides better attenuation of hemodynamic response and reduction of intraoperative remifentanil requirements in patients undergoing ESS. Postoperative pain seems to be better controlled after clonidine premedication as well.

The prevalence of infections and colonisation with Klebsiella pneumoniae strains isolated in ICU patients

BACKGROUND Klebsiella spp. are among the bacteria most commonly isolated from patients with infections in ICUs. The source of these infections may be the microflora of the patient or the hospital environment. Increasingly, Klebsiella strains are also being isolated from epidemic outbreaks. This situation is largely the result of widespread, irrational antibiotic use, the virulence of the bacterial strains and their ability to survive in the hospital environment. The purpose of this dissertation was to estimate the prevalence of Klebsiella pneumoniae strains isolated from patients hospitalised in a single ICU. METHODS Seventy-eight isolates of K. pneumoniae were studied. The identification and the susceptibility to selected antibiotics were tested by an automated system, VITEK2 Compact. For the analysed strains, the production of different beta-lactamases was noted. RESULTS Production of ESBL was detected in 64.1% of the K. pneumoniae strains isolated from infections and 74.4% from rectal swabs. Most of the strains were susceptible to imipenem (97.7%) and meropenem (96.1%). Sixty-nine (57.0%) of the analysed strains were identified as multidrug resistant. CONCLUSION Most of the analysed Klebsiella pneumoniae strains produced ESBL-beta-lactamases. The frequency of colonisation and infection with multidrug resistant strains of K. pneumoniae in patients hospitalised in the ICU is very high.