Association between intra-abdominal pressure and jugular bulb saturation in critically ill patients.

BACKGROUND: Disorders in cerebral circulation following elevated intra-abdominal pressure (IAP) may lead to silent brain ischemia, which can be serious problem in sedated critically ill patients. The aim of the present study was to analyse the possible association between jugular venous bulb pressure (JVBP) and jugular venous bulb saturation (SjO2) to IAP in critically ill patients. METHODS: Adult septic shock patients with acute kidney injury were studied just after the admission to Intensive Care Unit and after 24 and 48 hours of treatment. Patients were divided into: CVVH group (patients treated with continuous veno-venous haemofiltration) and furosemide group (patients treated with furosemide infusion). The IAP was measured via the bladder. The right jugular vein was retrogradely cannulated for JVBP and SjO2 measurement. Intra-abdominal hypertension was defined as a sustained increase of IAP equal to or above 12 mmHg. RESULTS: Forty patients (25 male and 15 female patients) were studied. In all participants, IAP strongly correlated with JVBP (P<0.001, r=0.73). This correlation was stronger in the furosemide group than the CVVH group. Moreover, an increase in IAP was related to an increase in JVBP and a decrease in SjO2. There was an inverse correlation between IAP and SjO2 (P<0.001, r=-0.55). This correlation was stronger in furosemide group than CVVH group. CONCLUSION: IAP is correlated to JVBP and inversely correlated to SjO2. Increase in IAP leads to elevation in JVBP and decrease in SjO2. Renal replacement therapy disturbs the correlation between IAP, JVBP and SjO2.

Intra-abdominal and abdominal perfusion pressure in patients undergoing coronary artery bypass graft surgery.

BACKGROUND: In 2006, the International Conference of Experts on Intra-abdominal Hypertension defined abdominal perfusion pressure (APP) as the difference between mean arterial pressure (MAP) and intra-abdominal pressure (IAP).The aim of the study was to analyse changes in IAP and APP in patients undergoing elective coronary artery bypass grafting (CABG). PATIENTS AND METHODS: Fifty patients undergoing CABG with extracorporeal circulation (ECC) and normovolemic haemodilution (NH) under general anaesthesia were studied. IAP and APP were measured during CABG and in the early postoperative period. Changes in IAP and APP were analysed according to degree of normovolemic haemodilution, age, body weight, body mass index (BMI), duration of anaesthesia, surgery, ECC, aorta clamping and other haemodynamic parameters. RESULTS: The induction of anaesthesia decreased IAP. Extracorporeal circulation resulted in IAP elevation, which was dependent on the degree of blood dilution. At any time point of the postoperative period IAP higher than 12 mmHg was noted in 22 patients (44%). Abdominal perfusion pressure decreased during ECC and on the morning of the first postoperative day. Intra-abdominal pressure strongly correlated with BMI and central venous pressure. The correlation between IAP and APP and other haemodynamic parameters was poor. CONCLUSIONS: 1) The induction of anaesthesia decreased IAP. 2) ECC resulted in an increase in IAP. 3) IAP increased in 44% of patients. 4) IAP strongly correlated with BMI and central venous pressure. 5) CABG with ECC resulted in a decrease in APP. 6) Changes in APP strongly correlated with MAP and poorly correlated with other haemodynamic parameters. 7) The changes in APP demonstrated a double-phase character.

Changes of blood magnesium concentration in patients undergoing surgical myocardial revascularisation.

BACKGROUND: Magnesium (Mg) is the second most relevant intracellular element, which plays an important role in many physiological processes. Magnesium disorders are particularly important in haemodynamically unstable patients, such as patients after extracorporeal circulation. The aim of this study was to analyze the changes in blood Mg levels in patients undergoing coronary artery bypass procedures with extracorporeal circulation. PATIENTS AND METHODS: Twenty male patients, aged 50-69, undergoing CABG with ECC under general anaesthesia, were included in the study. All of them were operated on due to Io and IIo degree coronary disease (according to CCS). The blood concentrations of Mg were examined in five stages: 1) before the induction of anaesthesia; 2) during extracorporeal circulation; 3) after surgery; 4) in the morning of the first postoperative day; 5) in the morning of the second postoperative day. The blood Mg concentrations were determined by spectrophotometric methods. RESULTS: The blood concentration of Mg decreased during extracorporeal circulation and immediately after surgery and increased in the morning of the first and second postoperative days. CONCLUSION: The CABG with extracorporeal circulation resulted in a significant decrease in blood Mg concentration.

The effect of preoperative magnesium supplementation on blood catecholamine concentrations in patients undergoing CABG.

BACKGROUND: It is well known that magnesium (Mg) plays an important role in many physiological processes such as regulation of blood catecholamine concentrations, particularly epinephrine (E) and norepinephrine (NE). The complex character of extracorporeal circulation (ECC) with intraoperative normovolemic haemodilution (NH) may alter blood Mg levels, which is likely to result in disorders of E and NE. The aim of this study was to analyze the influence of preoperative Mg supplementation on E and NE in patients undergoing CABG. PATIENTS AND METHODS: Forty male patients undergoing CABG under general anaesthesia were included. Patients were randomly divided into two groups: A--the patients receiving pre-operative magnesium supplementation and B--patients without pre-operative magnesium supplementation. The Mg, E and NE blood concentrations were measured in five stages: 1) before anesthesia after the radial artery cannulation, 2) during NH and ECC, 3) immediately after surgery, 4) in the morning of the 1st postoperative day, 5) in the morning of the 2nd postoperative day. The Mg levels were determined by spectrophotometric methods, E and NE were measured by radioimmunoassay methods. RESULTS: The CABG caused a decrease of Mg and an increase of E and NE in both groups, but the changes were significantly higher in group B. CONCLUSIONS: 1) CABG causes a decrease of Mg and an increase of E and NE; 2) Preoperative, oral supplementation of Mg substantially reduces intra- and postoperative disorders.

The relationship between magnesium, epinephrine and norepinephrine blood concentrations during CABG with normovolemic hemodilution.

The effects of procedures with extracorporeal circulation on the disturbance of relationships between blood magnesium (Mg), epinephrine, and norepinephrine levels have not been explicitly explained. It is assumed that both hypomagnesemia and increased concentration of the above mentioned hormones exert adverse effects on the myocardium often causing life threatening disorders. This problem is particularly important in cases of stunned myocardium, observed after extracorporeal circulation procedures. The complex nature of the procedures and the intraoperative normovolemic hemodilution (NH) employed are likely to alter Mg, epinephrine, and norepinephrine concentrations, as well as the above mentioned relations. The aim of the study was to evaluate the changes in blood Mg, epinephrine and norepinephrine concentrations in patients undergoing extracorporeal circulation and normovolemic hemodilution. The study encompassed 16 men operated on for stable coronary disease (I or II degrees according to the Canadian Scale). The patients were divided into two groups according to body weight: A) patients weighing less than 75 kg and B) patients weighing more than 75 kg. The degree of NH caused by constant volume of priming (1800 mL) was determined on the basis of hematocrit measurements and in relation to body weight. The examinations were conducted in 5 stages: 1) after radial artery cannulation before anaesthesia and surgery, 2) during hemodilution and deepest hypothermia, 3) after surgery before sending the patient to Intensive Postoperative care Unit, 4) in the first postoperative day, 5) in the second postoperative day. The observations showed an increase in epinephrine levels in group A in the second stage and of norepinephrine levels in stage 4. Decreased blood Mg levels were noted in all the patients in the second stage, however in group A significantly lower values were also observed in stage 3. Moreover, the correlation between Mg level changes and blood epinephrine and norepinephrine levels were observed. The study revealed significant effects of extracorporeal circulation procedures on adrenergic reactions as well as blood magnesium concentrations. It seems that the degree of NH is the main factor determining blood levels of Mg, epinephrine and norepinephrine during the use of a heart-lung apparatus, which may be particularly relevant in patients with impaired heart function and low body weight.

The degree of lymphocytic mitochondrial transmembrane potential and blood magnesium concentrations during coronary artery bypass grafting.

UNLABELLED: Magnesium (Mg) plays an important role in lymphocyte function. Low blood concentration of Mg may result in intralymphocyte imbalance and in turn may be associated with intensified apoptosis of peripheral blood lymphocytes. Due to its multistage character; extracorporeal circulation (ECC) may augment Mg disorders adding to the above mentioned pathology. The aim of this study was to assess the correlation between lymphocyte apoptosis and Mg concentration in the blood during the course of coronary artery bypass grafting (CABG) and in the early postoperative period. METHOD: Twenty male patients undergoing CABG with ECC under general anaesthesia were included in the study. For detection of apoptotic lymphocytes in the circulation, inner mitochondrial transmembrane potential (deltapsim) was measured with the use of chloromethyl-X-rosamine (CMXRos) and flow cytometry. Spectrophotometry was used for Mg blood concentration measurements. Peripheral blood samples were obtained in seven stages: 1) just before anaesthesia, 2) 2 hours after the beginning of surgery, 3) immediately after surgery, 4) 12 hours after the beginning of surgery, 5) 24 hours after the beginning of surgery, 6) 36 hours after the beginning of surgery, 7) 54 hours after the beginning of surgery. RESULTS: The statistically significant increases of lymphocyte apoptosis were noted in stages from 2 to 7. Blood Mg concentrations decreased in stages 2 and 3. There was negative correlation between Mg blood concentration in stages 2 and 3 and the intensity of lymphocyte apoptosis in the stage 5. CONCLUSIONS: 1) CABG with extracorporeal circulation was associated with a decrease of magnesium concentration in the blood and an increase of lymphocyte apoptosis intensity. 2) The decrease of magnesium blood concentration may increase the degree of lymphocyte apoptosis. 3) Lymphocyte apoptosis after extracorporeal circulation has a two-phase course.