Effect of cigarette smoking on the washout time of sevoflurane anesthesia

Background

Cigarette smoking affects the pharmacodynamic and pharmacokinetic behavior of many drugs and causes deterioration of pulmonary mechanics. We have evaluated the effect of cigarette smoking on washout time after one minimum alveolar concentration-h (1 MAC-h) of sevoflurane anesthesia.

Methods

We investigated the washout time of sevoflurane in 30 non-smoking and 30 healthy cigarette smoking (≥20 cigarettes/day for>1 year) ASA I-II physical status patients, aged 18-63 years, who were candidates for otorhinolaryngologic elective surgery under 1MAC-h standardized sevoflurane anesthesia. At the end of the surgery, the sevoflurane vaporizer was turned off and the time taken for the sevoflurane concentration to decrease to MAC-awake (0.3) and 0.1 MAC levels were recorded. In addition, the ratio of the fractions of inspired concentration (Fi) and expired concentration of sevoflurane (Fexp) at 1 MAC and Fexp of sevoflurane at 0.1MAC were recorded. The patients were mechanically ventilated during the washout time.

Results

We found no difference between the 2 study groups with regard to washout time of sevoflurane. The times of 1MAC down to MAC-awake (106 ± 48 sec in non-smokers vs 97 ± 37 sec in smokers, p > 0.05) and down to 0.1MAC (491 ± 187 sec in non-smokers vs 409 ± 130 sec in smokers, p > 0.05) were similar. Similarly, there were no significant differences in the ratios of Fi/Fexp at 1MAC (1.18 in non-smokers vs. 1.19 in smokers, p > 0.05) and Fexp of sevoflurane at 0.1MAC (0.26 in non-smokers vs. 0.25 in smokers, p > 0.05).

Conclusions

Washout time of 1MAC-h sevoflurane anesthesia is not appear to be effected by cigarette smoking in patients without significant pulmonary disease.

The renal effect of replacement fluids in controlled severe hemorrhagic shock: an experimental study

BACKGROUND

This experimental study examined the effects of resuscitation with Ringer's lactate (RL), 6% hydroxyethyl starch (130/0.4-HES), and the combination of RL and HES on renal function in hemorrhagic shock (HS).

METHODS

Twenty-four male New Zealand white rabbits weighing 2198-3435 g were divided at random into four groups. HS was constituted by maintaining the mean arterial blood pressure at 30 mmHg and blood lactate at >4 mM/L. Subsequently, Group 1 (control) was not resuscitated, while the study rabbits' resuscitation was initiated with RL (Group 2), HES (Group 3), or the combination of RL and HES (Group 4).

RESULTS

In all groups, the serum creatinine and blood urea nitrogen (BUN) levels were observed to be within normal limits, while the lactate dehydrogenase and alpha-1 microglobulin levels statistically significantly increased when time points were compared with beginning values (p<0.05). Furthermore, cystatin-C levels were observed to be increased after the HS (p<0.05), but returned to the normal level after resuscitation in all the study groups. Interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha levels were increased in all the rabbits after HS (p<0.05), and there were no significant differences among the study groups after resuscitation (p>0.05). There were no differences in the histological imaging between the groups (p>0.05).

CONCLUSION

The 6% HES (130/0.4) did not have any harmful effects on the kidney when it was used alone or in combination with crystalloid for resuscitation of HS in rabbits.

Timing of levosimendan in cardiac surgery

OBJECTIVE

Levosimendan (LS) is a new inodilator agent that improves cardiac contractility by increasing the sensitivity of troponin C to calcium, which usage in cardiac surgery has been growing in the recent years. We aimed to determine the best timing of the administration of LS in high-risk patients who underwent cardiovascular surgery.

METHODS

Fifteen patients were evaluated retrospectively who have left ventricular dysfunction, underwent open-heart surgery and were applied LS in different phases of operation. Patients were divided into 3 groups according to timing of LS. Levosimendan infusion (0. 1 microg-1kg-1min) was applied after the induction of anaesthesia (n=5) (Group 1), during the pump removal period (n=5) (Group 2) and in postoperative period (n=5) (Group 3). Demographic data, operative characteristics, mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP), pulmonary wedge capillary pressure (PWCP), cardiac index (CI), inotropic agent consumption, postoperative urine output, lactate levels of groups were compared between before and after LS treatment. Data were evaluated by Fisher exact, Kruskal-Wallis, Mann-Whitney U and Wilcoxon rank tests.

RESULTS

In all patients, urine output was satisfactory 24 hours after LS application. There was a significant increase in CI of all 3 groups (p=0.04). Also, there was a significant decrease in PCWP of all 3 groups before and after LS (p=0.04). There was a significant decrease in MPAP in Group 2 and 3 (p=0.04). Twenty- four hours after LS application, whereas all inotropic agents could be stopped in Group 1 and 2, in Group 3 inotropic infusion (dopamine [10 microg-1kg-1min (5-17.5)], dobutamine [15 microg-1kg-1min (5-20)] and adrenaline [0.4 microg-1kg-1min (0.15-0.65)]) couldn't be stopped (p=0.007). During postoperative period, in Groups 1 and 2 one case from each required intraaortic balloon pump, while in Group 3 four patients were applied intraaortic balloon pump (p=0.08).

CONCLUSION

According to our experience, LS is effective in high-risk cases during cardiac surgery, especially during the intra-operative and pump removal periods;however, no successful outcomes were observed during the post-operative period. As a result, case selection and timing should be performed well when using LS.

[Traumatic extracranial carotico-juguler fistulation]

BACKGROUND

Extracranial caroticovenous fistulae, if left untreated, may cause stroke, cerebral edema, and high output cardiac failure and may present with oculofacial signs. In this study, 5 cases with extracranial arteriovenous fistulae who were diagnosed and surgically treated promptly after trauma are presented.

METHODS

Five patients with extracranial traumatic caroti-cojuguler fistulation underwent urgent surgery in our department. Their mean age was 32.4 (range: 27-38). Mean door to operating room time was 2.4 hours. One patient underwent arcus aortography due to a large hematoma in the mediastinum. One patient underwent arterial Doppler ultrasound examination. The remaining three patients were diagnosed via physical examination.

RESULTS

There were three gunshot and two stab wounds. The right common carotid artery was injured in three cases and left common carotid artery in two. There was no early or late mortality. Cross-clamp time was 14.3+/-4.7 minutes. There was no major bleeding. One patient developed ischemic stroke secondary to hypotension due to massive bleeding before surgery and was transferred to the Department of Neurology on the 5th postoperative day.

CONCLUSION

We suggest that as soon as the diagnosis of traumatic caroti-cojuguler fistula is made, a surgical approach is effective and safe and may prevent possible complications due to delayed diagnosis and treatment.

The effects of sevoflurane, isoflurane and desflurane on QT interval of the ECG

BACKGROUND AND OBJECTIVE

To determine if there is any significant difference between the effects of desflurane, isoflurane and sevoflurane on the QT interval, QT dispersion, heart rate corrected QT interval and QTc dispersion of the electrocardiogram.

METHODS

The study was conducted in a prospective, double blind and randomized manner in a teaching hospital. Ninety ASA I patients, aged 16-50 yr, undergoing general anaesthesia for noncardiac surgery were studied.

RESULTS

There was no significant change in QT intervals during the study in any group (P > 0.05). QT dispersion in the sevoflurane group 49+/-14 ms vs. 37+/-10 ms; in the desflurane group 55+/-16 and 62+/-21 ms vs. 35+/-14 ms and in the isoflurane group 54+/-26 and 59+/-24 ms vs. 42+/-19 ms were significantly increased at 3 and 10 min after 1 MAC of steady end-tidal anaesthetic concentration compared with baseline values (P < 0.05). QTc values in the sevoflurane group were 444+/-24 and 435+/-2 1ms vs. 413+/-19 ms (P < 0.05), in the isoflurane group were 450+/-26 and 455+/-34 ms vs. 416+/-34 ms (P < 0.05), in the desflurane group were 450+/-26 and 455+/-34 ms vs. 416+/-34 ms (P < 0.05) at 3 and 10 min after reaching 1 MAC of anaesthetic concentration and significantly increased compared with baseline values. QTc dispersion increased significantly with sevoflurane 62+/-14 ms vs. 45+/-16 ms (P < 0.05); isoflurane 70+/-36 ms at 3 min and 75+/-36 ms at 10 min after reaching 1 MAC of anaesthetic concentration vs. 50+/-24 ms (P < 0.05); desflurane 67+/-25 ms at 3 min and 74+/-27 ms at 10 min after 1 MAC concentration vs. 41+/-22 ms (P < 0.05).

CONCLUSION

Sevoflurane, isoflurane and desflurane all prolonged QTd, QTc and QTcd but there were no significant intergroup differences.

The effect of pentoxifylline on the lung during cardiopulmonary bypass

Cardiopulmonary bypass (CPB) produces an inflammatory response due to the interaction of blood with a foreign body surface. The lungs are most affected by this inflammatory response. Pentoxifylline (PTX), a phosphodiesterase inhibitor and an inhibitor of leukocyte activation, is used to minimize damage in lungs where leukocytes play an important role. Twenty patients with mitral valve stenosis with planned mitral valve surgery were included in the study. The ten patients receiving pentoxifylline (PTX group) were administered 400 mg PTX orally TID for 3 days preoperatively and, following anesthetic induction, a 300 mg PTX infusion was given. The ten patients receiving no PTX were the control group (CT). Platelet and leukocyte counts, mean pulmonary arterial pressure (mPAP), pulmonary capillary wedge pressure (PCWP), cardiac index (CI), pulmonary vascular resistance (PVR), alveolar-arterial PO2 gradient (AaDO2) were measured just before and after CPB, and 2 h postoperatively. The number of the leukocytes increased in the blood samples drawn 15 min after CPB in both groups and 2 h postoperatively showed no statistical change. The number of platelets had decreased significantly at the end of the CPB in both groups and, 2 h postoperatively, there was a further decrease in the blood count in the control group (P < 0.05). There was no significant difference in either the preoperative or postoperative PAP, PAWP, and CI. Pulmonary vascular resistance increased in both groups following the CPB (CT, before: 136 +/- 44, after: 177 +/- 94 dyne. sec.cm-5; PTX, before: 151 +/- 82, after 182 +/- 43 dynes.sec.cm-5). Two hours postoperatively, a considerable increase continued in the control group (CT 219 +/- 170 dynes.sec. cm-5), while there was an insignificant increase in the PTX group (PTX 193 +/- 51 dynes.sec.cm-5) (P < 0.05). The alveolar-arterial PO2 gradient increased after the CPB in both groups but a moderate decrease was observed 2 h postoperatively. In lung biopsy specimens taken before and after the CPB, there was marked leukocyte sequestration in the control group, whereas the number of leukocytes was seen to be insignificant in the PTX group (P < 0.005). This dosage regimen of PTX inhibits the postoperative increase in PVR and greatly minimized leukocyte sequestration in the lung due to CPB.