Lauri S. Nuutinen

Hemodynamic changes due to Trendelenburg positioning and pneumoperitoneum during laparoscopic hysterectomy

More prolonged gynecological laparoscopic operations are being performed in recent years, and a steeper head‐down position is required. The early reports of hemodynamic changes during gynecologic laparoscopy are conflicting, and the effects of anesthesia, head‐down tilt and pneumoperitoneum have not been clearly separated. Invasive hemodynamic monitoring was carried out in 20 female ASA Class I‐II patients who underwent laparoscopic hysterectomy. Baseline measurements were made in the supine, supine‐lithotomy and Trendelenburg (25 30 degrees) positions in awake patients. Measurements were repeated in the supine‐lithotomy and Trendelenburg positions after induction of anesthesia, during laparoscopy 5 minutes after the beginning of peritoneal CO2‐insufflation (intra‐abdominal pressure 13–16 mmHg) and at 15‐minute intervals thereafter, after laparoscopy in the Trendelenburg and supine positions, after extubation and in the recovery room at 30‐minute intervals. Patients received balanced general anesthesia with isoflurane in 35% O2 in an oxygen/air mixture. End tidal PGO2 was maintained between 4.5–4.8 kPa (33—36 mmHg) by changing the minute volume of controlled ventilation.

A clinical and pharmacokinetic comparison of ropivacaine and bupivacaine in axillary plexus block

The clinical and pharmacokinetic properties of ropivacaine and bupivacaine, both 5 mg/mL, used in axillary plexus block were compared in 60 patients in this randomized, double-blind, parallel-group study. The axillary plexus was identified with a nerve stimulator and 30, 35, or 40 mL of drug, depending on body weight, was injected into the perivascular sheath. In 20 patients, venous blood samples for the pharmacokinetic measurement were obtained over 24 h. The median onset times for anesthesia and complete motor block were in the range of 12-48 min and 5-20 min, respectively. Thirty-eight percent of patients in the ropivacaine group and 29% in the bupivacaine group needed additional nerve block(s) or supplementary analgesia and 7% in the bupivacaine group needed general anesthesia for surgery. Anesthesia was achieved in 52%-86% of the evaluated six nerves in the ropivacaine group and in 36%-87% in the bupivacaine group; the lowest figures were seen in the musculocutaneous nerve. In the pharmacokinetic study the mean peak plasma concentrations (Cmax) were 1.28 +/- 0.21 mg/L in the ropivacaine group and 1.28 +/- 0.47 mg/L in the bupivacaine group and the median times to peak plasma concentration (tmax) were 0.86 h and 0.96 h, respectively. The median terminal half-lives (t 1/2) were 7.1 h and 11.5 h in the ropivacaine group and the bupivacaine group, respectively (P = 0.07). No statistically significant differences were found between ropivacaine and bupivacaine in either the clinical or the pharmacokinetic comparisons. (Anesth Analg 1995;81:534-8)

Ventilatory Effects, Blood Gas Changes, and Oxygen Consumption During Laparoscopic Hysterectomy

We evaluated the ventilatory effects and blood gas changes of prolonged CO (2)-pneumoperitoneum in normoventilated patients and examined the respiratory and gas exchange consequences of head-down positioning (25-30 degrees) and CO2 insufflation into the peritoneal cavity in 20 patients without major cardiorespiratory disorders in various phases of laparoscopic hysterectomy. The patients received general anesthesia with isoflurane, fentanyl, and vecuronium, and minute ventilation (MV) was adjusted to maintain the PETCO2 at 33-36 mm Hg throughout the entire procedure, either by increasing the tidal volume (TV) and keeping the respiratory rate (RR) at 12/min (10 patients) or by changing the RR and maintaining the TV at 8 mL/kg (10 patients). Arterial and mixed venous blood samples were collected simultaneously for blood gas analysis and for measurements of oxygen consumption, and respiratory mechanics and gases were recorded by an anesthetic gas analyzer and side stream spirometry device. Oxygen consumption decreased with anesthesia, remained stable to the end of the laparoscopy, increased soon after deflation of the pneumoperitoneum, and reached preanesthetic values during recovery. The MV requirement increased by approximately 30% after the start of CO2 insufflation, then increased somewhat further toward the end of the laparoscopy, reaching the highest level a few minutes after deflation of the intraabdominal gas. The compliance decreased by 20% with the head-down position and by an additional 30% with the increased intraabdominal pressure. PaCO2 and mixed venous PCO2 increased with CO2 insufflation, and the arterial to end-tidal PCO2 (a-etPCO2) gradient increased by 1.5 mm Hg during laparoscopy. A mild metabolic acidosis developed. The MV requirement was more among patients whose RR was changed to maintain normocapnia. In conclusion, there was a small increase in the a-etPCO2 gradient, indicating some increase in alveolar dead space during laparoscopy. Normocapnia during laparoscopy in healthy patients was achieved by maintaining the PETCO2 at a somewhat lower level than normal, preferably by increasing the TV of controlled ventilation. (Anesth Analg 1995;80:961-6)

Magnesium substitution in elective coronary artery surgery: A double-blind clinical study

Magnesium may be beneficial in the control of ventricular ectopy and supraventricular tachyarrhythmias after coronary artery bypass graft (CABG) surgery, but it is not known whether a high-dose magnesium regimen is superior to a regimen keeping the patient normomagnesemic. A prospective randomized and double-blind clinical comparison was performed in 81 elective CABG patients in order to assess the effects of two different magnesium infusion regimens on electrolyte balance and postoperative arrhythmias. Forty-one patients (high-dose group, H) received 4.2 +/- 0.7 g (mean +/- SD), of magnesium sulfate before cardiopulmonary bypass, followed by an infusion of 11.9 +/- 2.8 g of magnesium chloride until the first postoperative (PO) morning, and a further 5.5 +/- 1.0 g until the second PO morning. Forty patients (low-dose group, L) received magnesium sulfate only after bypass to a total of 2.9 +/- 0.5 g at the first, and 1.4 +/- 0.1 g at the second PO morning. A blood cardioplegia technique was used in both groups, including bolus doses of magnesium chloride to a total of 2.4 +/- 0.6 g and 2.3 +/- 0.6 g to H and L patients, respectively. Continuous Holter tape-recording was used for 12 to 15 hours preoperatively, and for 48 hours postoperatively. Serum magnesium peaked in H patients on the first PO morning at 1.60 +/- 0.25 mmol/L, whereafter it declined to the normal level on the third PO morning. Patients in the L group were normomagnesemic, except after the start of bypass.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravenous ketoprofen for pain relief after total hip or knee replacement

Background: There are few studies in which ketoprofen, a propionic acid derivate NSAID, has been tested as an intravenous postoperative analgesic. The aim of this double‐blind, randomized, placebo‐controlled work was to study the tolerability and efficacy of intravenous ketoprofen in seventy‐six patients undergoing hip or knee total endoprothesis surgery using three different doses.

Comparison of Tropisetron, Droperidol, and Saline in the Prevention of Postoperative Nausea and Vomiting After Gynecologic Surgery

This study was performed to compare the efficacy of tropisetron, droperidol, and saline in the prevention of postoperative nausea and vomiting (PONV) and to compare the possible adverse effects of these drugs in gynecologic incontinence surgery.Using a randomized, double-blind study design, we studied 150 women undergoing gynecologic incontinence surgery with standardized general anesthesia. At the end of surgery, the patients received either tropisetron 5 mg, droperidol 1.25 mg, or 0.9% saline intravenously (IV). As a rescue antiemetic, the patients received metoclopramide 10 mg IV. The episodes of nausea, retching, and vomiting; the need for rescue treatment; and the type and severity of adverse events were recorded at four occasions during the 48-h observation period. Pain, anxiety, drowsiness, and general satisfaction were also evaluated on a linear numerical scale of 0-10. Complete response (no PONV within the 48-h observation period) occurred similarly in the study groups (tropisetron 25%, droperidol 22%, and placebo 18%). Tropisetron and droperidol had no effect on the incidence of nausea and retching. However, the incidence of vomiting was significantly less in the tropisetron group than in the placebo group (tropisetron 19%, droperidol 45%, and placebo 57%). The number of emetic episodes (retching and/or vomiting) per patient within 48 h was significantly decreased under tropisetron when compared with placebo (tropisetron 2.5 +/- 3.4, droperidol 4.2 +/- 6.1, placebo 5.9 +/- 7.1). With regard to adverse events, the patients in the droperidol group had significantly more anxiety than the placebo group (2-6 h postoperatively), more drowsiness than the tropisetron and placebo groups (0-2 h postoperatively), and more dissatisfaction than the tropisetron (0-6 h postoperatively) and placebo groups (2-6 h postoperatively). We conclude that tropisetron given 5 mg IV during anesthesia in gynecologic incontinence surgery effectively prevents vomiting but not nausea and retching, while 1.25 mg IV droperidol fails to prevent any of these emetic symptoms and results in adverse events. (Anesth Analg 1997;84:662-7)

Transfusion policies in coronary artery bypass — a nationwide survey in Finland

Background: Since the discovery of HIV, minimizing the use of donor blood has become increasingly important in surgical activity. In Finland, however, the use of homologous red blood has grown considerably during the past years. Therefore, we found it necessary to conduct a nationwide survey of transfusion practices in elective surgery. This report deals with transfusions in coronary artery bypass (CABG) operations in all Finnish cardiac centres.

Is routine ipsilateral adrenalectomy during radical nephrectomy harmful for the patient

To investigate the effects of unilateral adrenalectomy on the postoperative course and laboratory parameters, 40 patients with a renal tumour were randomized either to undergo (n = 20) or not to undergo (n = 20) ipsilateral adrenalectomy. Adrenal hormone (cortisol, epinephrine, norepinephrine and aldosterone), adrenocorticotropic hormone, electrolyte, creatinine, growth hormone, glucose, insulin and free fatty acid concentrations were measured preoperatively and postoperatively. Cortisol and epinephrine concentrations were elevated immediately after the operation but returned to preoperative levels within the first 2 postoperative days. There were no significant differences between the adrenalectomy and non-adrenalectomy groups, except that the cortisol concentration was higher in the latter in the afternoon of the day of surgery. The conclusion is that no long-term shortage of adrenal hormones is caused by unilateral adrenalectomy. Other metabolic and endocrine responses were identical in the groups. Thus ipsilateral adrenalectomy does not seem to be harmful to the patient and the need for it must be resolved on the basis of local tumour factors.

The role of nitrous oxide in postoperative nausea and recovery in patients undergoing upper abdominal surgery

The effect of nitrous oxide on postoperative nausea/vomiting and alertness were studied in 50 patients undergoing elective upper abdominal surgery. The study period lasted 20 h. Patients were randomly assigned to receive thiopentone‐fentanyl‐isoflurane‐pancuronium anaesthesia with either 70% nitrous oxide‐oxygen (Group I) or air‐oxygen (Group II). There were no differences between the groups regarding age, sex, weight or amount or per‐ and postoperative analgetics given. The mean inspiratory isoflurane concentrations were 0.6% and 1.15% in Groups I and II, respectively. The postoperative alertness was tested by a visual analogue scale (0–10) for 6 h postoperatively. Omitting nitrous oxide did not decrease the frequency of postoperative nausea, although the symptoms were milder in the air group. The patients without nitrous oxide were alert earlier, in spite of a higher isoflurane concentration: VAS from 5 to 8.7 vs from 2.8 to 6.9 during the first 6 postoperative hours.

Catheter‐Related Complications of Total Parenteral Nutrition (TPN): A Review.

Aubaniac in 1952 was the first to describe the percutaneous infraclavicular subclavian technique ( 1). Since then, the indications for use of the central venous catheter (CVC) have steadily increased. The most important indications are measurement of central venous pressure during shock treatment, intervention in high-risk patients, and long-term parenteral administration of drugs and nutrient solutions. Although total parenteral nutrition is being increasingly given in a peripheral vein with regular change of the infusion cannula, CVC is of great benefit despite the accompanying risk of more serious complications. The main complications arising during long-term treatment using CVC can be divided as shown in Table 1. 1. Mechanical complications: pneumothorax and perforated vessel are the most common ones, and are likely to occur in about 4-67; of cases (2). However, use of the Seldinger technique (3) , in which catheter introducer is used, has to some extent reduced these risks. There is a risk of air embolism, not so much in connection with the actual catheterization but more due to the fact that the connections may become loose in an ambulatory patient. All connections should therefore be screwed tight (Luer lock). 2. Thrombosis is a common complication, but it is often nonocclusive and thus asymptomatic and difficult to diagnose in most cases. 3. Phlebitis is a common problem with long antecubital catheters. 4. Infection and sepsis today pose the main problem in long-term treatment with CVC. 5. Catheter occlusion is a practical drawback in longterm parenteral nutrition. The incidence of complications depends on factors such as those shown in Table 2. Experience obviously plays an important role as far as the mechanically induced complications are concerned. Inexperienced staff should avoid deep punctures near the thorax, choosing, for example, a long antecubital CVC in spite of its drawbacks, particularly thrombophlebitis, which is a less serious complication than pneumothorax. The elasticity and thrombogenicity of the catheter material varies (4). Polyvinylchloride (PVC) has been on the market for a long time. I t is semirigid from the very beginning, but becomes even more rigid as the pftalates included for softening are gradually lost. This increases cracking, intimal injury, thrombosis and vein perforation. Polyethylene is a semisoft material and less irritating to tissues than PVC, but readily causes intimal lesion and thrombosis. Silicone is a soft material giving rise to a low incidence of thrombosis. The incidence of silicone-induced thrombophlebitis is sufficiently high to preclude the use of this material in the antecubital vein. Polyurethane is still less thrombogenic and tissue irritating than silicone, and also causes thrombophlebitis clearly less often.