Sentinel node mapping affects intraoperative pulse oximetric recordings during breast cancer surgery

BACKGROUND

In invasive breast cancer lymphatic mapping with patent blue vital dye (PBV) is used intraoperatively to identify the sentinel lymph nodes: the first axillary node draining the mammary lymphatic basin and first involved by the metastatic growth in breast cancer. Patent blue vital dye spreads to tissues giving a bluish tinge to patients. We have noted the possibility that intraoperative peripheral pulse oximetric (SpO2) values are artificially low when intradermal PBV is used.

METHODS

Twenty patients with normal pulmonary function undergoing breast cancer surgery in standardized anesthesia either did or did not receive intradermal PBV sentinel node marking. The radial artery was cannulated for blood-gas-analysis; arterial oxygen tension (PaO2); and arterial oxygen saturation (SaO2). Peripheral oxygen saturation was measured using the light absorption technique. Red and infrared light (660 and 900 nm), used by pulseoxymetry, is partially absorbed when passing through the tissue. The amount of light absorbed is sensed and saturation calculated. The color of the skin was evaluated.

RESULTS

Peripheral oxygen saturation decreased only immediately after the injection of PBV, and remained at a significantly lower level (P<0.001) throughout the operation and up to 90 min postoperatively. Arterial oxygen tension and SaO2 values did not decrease after intradermal PBV. Patent blue vital dye made patients' skin more bluish (P<0.001). No changes in SpO2, PaO2 and SaO2 were found in control patients.

CONCLUSION

The spectrum of PBV has a peak absorption at 640 nm, thus making the SpO2 values incorrect. Peripheral oxygen saturation values are falsely low and true arterial oxygenation is not impaired when PBV is used during sentinel node mapping.

Clonidine provides opioid-sparing effect, stable hemodynamics, and renal integrity during laparoscopic cholecystectomy

BACKGROUND

Carbon dioxide pneumoperitoneum causes a hemodynamic stress response and decreases urine output because of an activated renin-angiotensin-aldosterone system (RAAS). Clonidine is a potent antihypertensive drug that suppresses RAAS.

METHODS

The effects of clonidine 4.5 mg/kg or saline on hemodynamics, neuroendocrine response, and renal parameters were compared in 30 healthy patients undergoing laparoscopic cholecystectomy.

RESULTS

Heart rate, arterial blood pressures, and plasma renin activity were lower during and after pneumoperitoneum in patients with clonidine. There were no differences in urine output, urine oxygen tension (reflecting medullary perfusion), or antidiuretic hormone between the groups. N-acetyl-b-D-glucosaminidase, a marker of proximal tubular damage, was minimally elevated after clonidine.

CONCLUSIONS

Clonidine enabled stable hemodynamics and prevented activation of RAAS seen as unchanged plasma renin activity. Clonidine may be beneficial during laparoscopy in patients with hypertension, cardiovascular, and/or renal diseases.

The effect of ketorolac and sevoflurane anesthesia on renal glomerular and tubular function

We assessed the renal effects of the combination of ketorolac and sevoflurane anesthesia by using sensitive and specific markers of renal proximal and distal tubular and glomerular function. Thirty women (ASA physical status I and II) undergoing breast surgery received either ketorolac 30 mg IM or saline at premedication, at the end, and 6 h after anesthesia maintained with sevoflurane. Peak levels of serum fluoride at 2 h after the end of anesthesia were 30.1 micromol/L (21.0-50.0 micromol/L) in the Ketorolac group and 33.3 micromol/L (13.0-38.0 micromol/L) in the Control group (mean and range, not significant). Urine alpha1-microglobulin indexed to urine creatinine was increased from 2 h after the start of anesthesia until the first postoperative day in the Ketorolac group (peak level, 0.8 +/- 0.4 mg/mmol; upper limit of normal, 0.7 mg/mmol) but did not change in the Control group. Urine glutathione-S-transferase (GST)-alpha indexed to urine creatinine (GST-alpha/creatinine) and GST-pi/creatinine were increased 2 h after anesthesia and returned to baseline values thereafter in both groups. There were no changes in serum cystatin C and urine kallikrein or urine output per hour between groups. The perioperative administration of ketorolac to healthy, well hydrated patients anesthetized with sevoflurane did not produce renal glomerular or tubular dysfunction.

IMPLICATIONS

Ketorolac 90 mg IM, given in divided doses over approximately 10 h to patients anesthetized with sevoflurane with a fresh gas flow rate of 4-6 L/min, did not result in clinically significant changes in renal glomerular or tubular function.

[Technical resources in obstetrics, and pain and pain relief during delivery]

An outline is given about the methods of pain relief from 1847 when J.Y. Simpson introduced ether and chloroform in obstetrics until the different methods of regional anaesthesia. The connection between pain in labour and the contractility of the uterus is illustrated. The way of influencing both the contractility and the pain is also described. The use of psychoprophylaxis in obstetrics completes the historical survey.

Sevoflurane mask induction of anaesthesia is associated with epileptiform EEG in children

BACKGROUND

Sevoflurane inhalation induction of anaesthesia is widely used in paediatric anaesthesia. We have found that this method is frequently associated with epileptiform electroencephalogram (EEG) in adults, especially if controlled hyperventilation is used.

METHODS

We assessed EEG during sevoflurane inhalation induction in 31 children, aged 2-12 yr. Anaesthesia was induced with 8% sevoflurane in O2 in N2O 1:2. The patients were randomized to undergo controlled ventilation (CV group), or to breathe spontaneously (SB group) for 5 min. EEG was recorded as were noninvasive blood pressure and heart rate (HR). EEG recordings were classified by a clinical neurophysiologist.

RESULTS

Three different types of interictal epileptiform discharge were detected. Suppression with spikes (SSP) was found in 25% and 0% in the CV and SB groups, rhythmic polyspikes (PSR) in 44% and 20%, and periodic epileptiform discharges (PED) in 44% and 0% (P<0.01), respectively. The incidence of all different types of interictal epileptiform discharge (SSP+PSR+PED) was 88% and 20% (P<0.001), respectively. Epileptiform EEG was associated with increased heart rate and blood pressure during anaesthetic induction.

CONCLUSION

Both ventilation modes produced epileptiform EEG. With controlled ventilation, epileptiform discharges were seen in 88% of children. This warrants further studies of the suitability of this induction type in general, and especially in children with epilepsy.

Modifying the cellular transport of DNA-based vaccines alters the immune response to hantavirus nucleocapsid protein

Puumala virus is a member of the hantavirus genus (family Bunyaviridae) and is one of the causative agents of hemorrhagic fever with renal syndrome (HFRS) in Europe. A genetic vaccination approach was conducted to investigate if the immune response could be modulated using different cellular secretion and/or localisation signals, and the immune responses were analysed in BALB/c mice and in a bank vole infectious model. Rodents vaccinated with DNA constructs encoding the antigen fused to an amino-terminal secretion signal raised significantly higher antibody levels when compared to using constructs lacking secretion signals. Furthermore, the ratios of the IgG subclasses (IgG2a/IgG1) were raised by the use of cellular localisation signals, indicating a more pronounced Th1-type of immune response. The majority of the mice, or bank voles, immunised with DNA encoding a secreted form of the antigen showed a positive lymphoproliferative response and were protected against challenge with Puumala virus (strain Kazan-wt).

Cyclosporine induces myocardial connective tissue growth factor in spontaneously hypertensive rats on high-sodium diet

BACKGROUND

The introduction of cyclosporine (CsA) has led to an improvement in the prognosis of solid organ transplantation. However, drug-induced hypertension and nephrotoxicity, associated with the development of atherosclerosis and coronary heart disease, still worsen the long-term outcome of CsA-treated patients. Whether the CsA-induced myocardial changes are associated with the induction of connective tissue growth factor (CTGF), a recently found polypeptide implicated in extracellular matrix synthesis, is not known.

METHODS

Spontaneously hypertensive rats (8-9 weeks old) were treated with CsA (5 mg x kg(-1) x d(-1) subcutaneously) for 6 weeks. The influence of angiotensin-converting enzyme inhibition (enalapril 30 mg x kg(-1) x d(-1) orally) and angiotensin-1 receptor blockade (valsartan 3 and 30 mg x kg(-1) x d(-1) orally) on CsA toxicity was also investigated. Myocardial morphology was examined, and vascular lesions were scored. Localization and the quantitative expression of CTGF, as well as collagen I and collagen III, mRNA were evaluated by in situ hybridization and Northern blot.

RESULTS

CsA-induced hypertension and nephrotoxicity were associated with myocardial infarcts and vasculopathy of the coronary arteries. CsA increased myocardial CTGF, collagen I, and collagen III mRNA expressions by 91%, 198%, and 151%, respectively. CTGF mRNA expression colocalized with the myocardial lesions. Blockade of the renin-angiotensin system prevented vascular damage and the CsA-induced CTGF, collagen I, and collagen III mRNA overexpressions in the heart.

CONCLUSIONS

CsA increases CTGF, collagen I, and collagen III mRNA expressions in the heart. The induction of CTGF gene is mediated, at least in part, by angiotensin II.

Ketorolac is not nephrotoxic in connection with sevoflurane anesthesia in patients undergoing breast surgery

Ketorolac, which may cause renal vasoconstriction by cyclooxygenase inhibition, is often administered to patients anesthetized with sevoflurane that is metabolized to inorganic fluoride (F(-)), another potential nephrotoxin. We assessed this possible interaction using urine N-acetyl-beta-D-glucosaminidase indexed to urinary creatinine (U-NAG/crea) as a marker of proximal tubular, beta2-microglobulin as a tubular, urine oxygen tension (P(u)O(2)) as a medullary, and erythropoietin as a marker of tubulointerstitial damage. Thirty women (ASA physical status I-II) undergoing breast surgery were included in our double-blinded study. They were allocated into two groups receiving either ketorolac 30 mg IM (Group K) or saline (Group C) at the time of premedication, at the end of, and 6 h after anesthesia maintained with sevoflurane. Urine output, U-NAG/crea, P(u)O(2,) serum creatinine, urea, and F(-) were assessed. Blood loss was larger in Group K (465 +/- 286 mL vs 240 +/- 149 mL, mean +/- SD, P < 0.05). The MAC-doses of sevoflurane were similar. U-NAG/crea increased during the first 2 h of anesthesia and serum F(-) peaked 2 h after the anesthesia without differences between the groups. There were no statistically significant changes in P(u)O(2), erythropoietin, beta2-microglobulin, serum creatinine, urea, or urine output during anesthesia or the recovery period in either group. Our results indicate that the kidneys are not affected by ketorolac administered in connection with sevoflurane anesthesia.

IMPLICATIONS

The different kinetics of N-acetyl-beta-D-glucosaminidase indexed to urinary creatinine and serum inorganic fluoride during and after sevoflurane anesthesia suggest that the observed mild renal tubular function deterioration is not caused by inorganic fluoride. Administration of ketorolac IM is therefore considered safe in adequately hydrated healthy adult patients given sevoflurane anesthesia.

A test for cleaning and disinfection processes in a washer-disinfector

Disinfection processes such as heat, aldehydes or alcohols kill vegetative microorganisms but do not necessarily remove other organic contamination. Organic residues impair the result of low-temperature sterilisation processes. Heat-stable organic residues may give rise to clinical symptoms in the patient. Standards are available in Britain and in Sweden for the examination of cleaning processes in washer-disinfectors. The test substances are artificial soil or blood. These standards are based on visual inspection of instruments or equipment. They cannot be used for examination of tubular instruments, nor can they be quantified. For validation of cleaning procedures a simple quantifiable method, which can be performed in an infection control laboratory is needed. We have used suspensions in horse blood of Enterococcus faecalis bacteria and Bacillus subtilis spores to test disinfection and cleaning in a washer-disinfector. Instruments used for laparoscopic surgery were contaminated with a blood bacteria suspension containing 10(7) organisms/ml and then dried and processed in a washer-disinfector using a regular process. Remaining microbial contamination was cultured quantitatively. Nineteen objects were investigated in 10 experiments each. Cleaning, measured as log reduction >5-6 of B. subtilis, was achieved on surfaces that were adequately in contact with the water flow in the machine. Disinfection (and cleaning) measured as log reduction >5-6 of E. faecalis was successful at all points examined. The test method is simple and quantifiable, and can be used to evaluate and to improve cleaning and disinfection processes.

Are diabetic patients in danger at renal transplantation? An invasive perioperative study

It is assumed that diabetic patients with uraemia have more complications at renal transplantation than those who are not diabetic. We compared the preoperative ECGs, and invasive perioperative haemodynamic and oxygenation parameters in 15 diabetic and 15 non-diabetic uraemic patients undergoing renal transplantation. The number of patients with increased QT dispersion in the ECG was higher in diabetic than in non-diabetic patients (P<0.05). Before anaesthesia, heart rate and mean arterial pressure were higher (P<0.05) in the diabetic than in the non-diabetic group. After preanaesthetic volume loading all patients showed a hyperdynamic circulation, which subsided during anaesthesia. However, stroke volume index remained unchanged. Four patients in the diabetic group and six in the non-diabetic group needed additional oxygen therapy after surgery. No cardiac dysrhythmias were noted. However, the increased QT dispersion in diabetic patients calls for an adequate perioperative ECG monitoring for dysrhythmias. The diabetic and non-diabetic uraemic patients performed equally well at renal transplantation. In conclusion, renal transplantation for diabetics is justified.

Dietary potassium and magnesium supplementation in cyclosporine-induced hypertension and nephrotoxicity

BACKGROUND

Cyclosporine A (CsA)-induced hypertension and nephrotoxicity are aggravated by high sodium intake. Accumulating evidence suggests that potassium and magnesium supplementation could protect against the detrimental effects of dietary salt. In the present study, we tested the hypothesis of whether concurrent supplementation with potassium and magnesium could protect against the development of CsA-induced hypertension and nephrotoxicity more effectively than supplementation with one mineral alone.

METHODS

Eight-week-old spontaneously hypertensive rats (SHRs) were divided into four groups (N = 10 in each group): (1) CsA group (5 mg/kg subcutaneously) receiving high-sodium diet (Na 2.6%, K 0.8%, Mg 0.2% wt/wt); (2) CsA group receiving a high-sodium, high-potassium diet (Na 2.6%, K 2.4%, Mg 0.2%); (3) CsA group receiving high-sodium, high-magnesium diet (Na 2.6%, K 0.8%, Mg 0.6%); and (4) CsA group receiving high-sodium, high-potassium, high-magnesium diet (Na 2.6%, K 2.4%, Mg 0.6%).

RESULTS

CsA induced severe hypertension and deteriorated renal functions in SHRs on high-sodium diet. Histologically, the kidneys showed severe thickening of the media of the afferent artery with fibrinoid necrosis. Potassium supplementation lowered blood pressure (198 +/- 5 vs. 212 +/- 2 mm Hg, P < 0.05) and partially prevented the development of proteinuria (-25%, P < 0.05). Magnesium supplementation decreased blood pressure to the same extent but improved renal functions more effectively than potassium. The greatest protection against CsA toxicity was achieved when dietary potassium and magnesium supplementations were combined. Urinary N-acetyl-beta-D-glucosaminidase (NAG) excretion, a marker for renal proximal tubular damage, increased progressively in CsA-treated SHRs on the high-sodium diet. Neither potassium nor magnesium influenced urinary NAG excretion. We also estimated the activity of the renal dopaminergic system by measuring 24-hour urinary dopamine excretion rates. CsA suppressed the renal dopaminergic system during high-sodium diet. Magnesium supplementation, alone and in combination with potassium, protected against the development of renal dopaminergic deficiency in CsA-treated SHRs on high-sodium diet. Magnesium supplementation increased plasma-free ionized magnesium (iMg) and bone magnesium by 50 and 16%, respectively.

CONCLUSIONS

Our findings indicate that both potassium and magnesium supplementations showed beneficial effects against CsA-induced hypertension and nephrotoxicity. The protective effect of magnesium clearly exceeded that of potassium. The greatest protection against CsA toxicity was achieved when potassium and magnesium were combined. We also provide evidence that the development of CsA-induced glomerular, tubular, and vascular lesions are associated with renal dopaminergic deficiency.

Beneficial effects of dietary magnesium and potassium on cardiac and renal morphologic features in cyclosporin A-induced damage in spontaneously hypertensive rats

BACKGROUND

Cyclosporin A-induced hypertension is dependent on the level of dietary salt. We investigated whether dietary magnesium or potassium could protect against cyclosporin A-induced cardiac and renal damage in spontaneously hypertensive rats (SHRs) on high-sodium diet.

METHODS

Eight-week-old SHRs were divided into 4 groups: (1) receiving a high-sodium diet, (2) receiving a high-sodium, high-potassium diet, (3) receiving a high-sodium, high-magnesium diet, and (4) receiving a high-sodium, high-potassium, high-magnesium diet. The effects of cyclosporin A in SHRs on a relatively low-sodium diet and in normotensive Wistar-Kyoto rats were also examined. Cardiac and renal morphologic condition was assessed, and tissue damage was scored by light microscopy after 6 weeks of cyclosporin A treatment.

RESULTS

In SHRs on a high-sodium diet, cyclosporin A caused luminal narrowing of the coronary arteries, left ventricular scarring, and damage in the renal arterioli and glomeruli. Dietary magnesium supplementation alone and in combination with potassium protected against these changes, whereas potassium alone was less effective. Cyclosporin A treatment caused only minor histopathologic changes in SHRs receiving a low-sodium diet. Interestingly, the detrimental interaction between cyclosporin A and a high-sodium diet was also observed in normotensive Wistar-Kyoto rats.

CONCLUSIONS

Dietary magnesium, especially in combination with potassium, protects against cyclosporin A-induced cardiac and renal damage.

Epileptiform EEG during sevoflurane mask induction: effect of delaying the onset of hyperventilation

BACKGROUND

Hyperventilation during sevoflurane-N2O-O2 mask induction in adults is associated with a hyperdynamic circulatory response and epileptiform electroencephalogram (EEG). We tested the hypothesis that delaying onset of hyperventilation will prevent severe (periodic) epileptiform EEG and hyperdynamic response.

METHODS

Thirty patients were randomized to receive either delayed (group D, n=15) or immediate (group I, n=15) onset of hyperventilation during sevoflurane (8% in N2O 50%) mask inhalation induction with single-breath method for unconsciousness. Fifteen patients were allowed to breathe spontaneously for 2 min after loss of consciousness and controlled hyperventilation (ETCO2 <4%) was started thereafter. In 15 patients controlled hyperventilation was started immediately after loss of consciousness. EEG was recorded, and mean arterial pressure (MAP) and heart rate (HR) registered.

RESULTS

Epileptiform EEG patterns were seen in 13 patients in group I and in 9 patients in group D (n.s.). Periodic epileptiform discharges (PED) tended to occur more often in group I (P=0.07). Heart rate and MAP were higher in group I than in group D from 2 min to 3 min (P < 0.05), and both HR and MAP rose significantly from the baseline in group I. In group D, HR but not MAP rose significantly from baseline.

CONCLUSION

Regardless of its timing, hyperventilation at a high sevoflurane concentration produced severe epileptiform EEG with a hyperdynamic response. PED tended to occur more often with immediate onset of hyperventilation.