[Ventricular tonometry during laparoscopic cholecystectomy]. / Ventrikeltonometri under laparoskopisk kolecystektomi.

Changes in gastric mucosal-pH (pHi) are correlated with the oxygenation of the gastric mucosa. We have measured the gastric mucosal-pH (pHi) in 11 healthy patients undergoing laparoscopic cholecystectomy and calculated the "pH-gap" as the difference between arterial-pH and pHi. The measurements were obtained at 30 minute intervals from the induction of anaesthesia to the end of surgery. The pHi decreased during surgery, but the pH-gap showed only insignificant changes. The results of this study did therefore not indicate gastric mucosal hypoxia during laparoscopic cholecystectomy.

Antioxidant treatment with N-acetylcysteine during adult respiratory distress syndrome: a prospective, randomized, placebo-controlled study.

OBJECTIVE: To examine whether the antioxidant N-acetylcysteine could ameliorate the course of the adult respiratory distress syndrome (ARDS) in man. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Medical and surgical ICU in a regional hospital. PATIENTS: Sixty-six ICU patients with ARDS. INTERVENTIONS: Patients with ARDS (PaO2/FiO2 ratio less than 250 torr) were treated with either the antioxidant N-acetylcysteine 150 mg/kg as a loading dose and then 20 mg/kg/hr, or with placebo for 6 days. MEASUREMENTS AND MAIN RESULTS: No improvement could be demonstrated in the PaO2/FiO2 ratio in the study group as compared with the control group on any day. Pulmonary compliance was higher in the N-acetylcysteine group than in the placebo group on all days, but this difference did not reach the chosen 5% level of significance. No difference between the two groups could be demonstrated on chest radiograph or on survival rate. We documented that N-acetylcysteine acts as an anticoagulant and perhaps decreases pulmonary fibrin uptake during ARDS. CONCLUSIONS: N-acetylcysteine might be of benefit in ARDS. Before further clinical studies are started, problems with N-acetylcysteine and coagulation have to be elucidated in order to find out whether N-acetylcysteine could have a beneficial effect in the treatment of ARDS.

[A pharmacologic respiratory stimulant, doxapram, used in acute deterioration in patients with chronic respiratory failure]. / En farmakologisk respirator, doxapram, ved akut forvaerring af kronisk respirationssvigt.

In a controlled study with random allocation, the effect of doxapram (Dopram), a respiratory stimulant, was evaluated in 25 patients with acute on chronic respiratory failure requiring ventilator support. Eleven patients were allocated to mechanical ventilation and 14 to treatment with doxapram given as a variable rate infusion. In the doxapram group only four were transferred to mechanical ventilation after 1 1/2 to three days of treatment. In these patients, the problem giving rise to the acute exacerbation, was not under control at the time of ventilator intervention. In the remainder of the group, antibiotics, diuretics and bronchodilators had successfully treated the exacerbation. All patients were discharged alive. In the doxapram-treated group duration of hospitalization was nine days compared to 14 days (median values) in the ventilator-treated group. Only minor side-effects from doxapram were observed, and it is concluded that this respiratory stimulant can be used as a primary drug in patients with acute respiratory failure and chronic airflow limitation.

Flumazenil in total intravenous anaesthesia using midazolam and fentanyl.

Forty patients, scheduled for elective surgery in a thoracic and vascular surgical unit, were anaesthetized by a total intravenous anaesthesia technique using midazolam and fentanyl. Subsequent reversal of anaesthesia by the specific benzodiazepine antagonist flumazenil was evaluated in a double-blind trial. The patients were observed in the recovery room postoperatively until the next morning, and their recovery was repeatedly evaluated during the first 240 min after anaesthesia. Six patients in the placebo group required an oral airway or an endotracheal tube during the first hours of recovery, whereas none who received flumazenil did. The respiratory rate was significantly higher after flumazenil than placebo during the first 4 h postoperatively (Anova, P less than 0.01). Blood pressure and heart rate were not different between the two groups. The degree of sedation, orientation in time and space and the ability to cooperate were significantly superior after flumazenil than placebo (Anova, P less than 0.01). Some degree of resedation was observed in both groups, affecting 95% of the patients who received flumazenil against 30% after placebo (Mann-Whitney, P less than 0.05). No adverse reactions attributable to the use of flumazenil were encountered.

In vitro effect of etomidate and thiopental on granulocyte migration.

An increased mortality has been reported during long-term etomidate infusion. Inhibition of adrenal corticosteroid synthesis has been incriminated - but other factors related to host defence cannot be excluded. Using an under-agarose assay, we investigated the effect of etomidate on in vitro granulocyte migration. Unlike thiopental (50 micrograms/ml), etomidate (4-32 micrograms/ml) did not affect either spontaneous or directed migration. Impaired granulocyte migration is an unlikely cause of morbidity during long-term etomidate infusion.

Psychomimetic reactions after low-dose ketamine infusion. Comparison with neuroleptanaesthesia.

Low-dose ketamine anaesthesia was compared with neuroleptanaesthesia, in respect of immediate and longer-term psychomimetic reactions, in 40 female patients undergoing elective gynaecological surgery. Qualitatively, but not quantitatively, different psychomimetic reactions occurred in both groups. In the neurolept group the predominant complaint was of a dissociative nature, reported after 24 h by 11 (55%) of the patients, while in the ketamine group the predominant experience was dreaming, reported by eight (40%) of the patients after 24 h. Interviews after 3 months revealed a low frequency of psychomimetic reactions in both groups. However, 30% of all the patients (12) complained of impairment of intellectual function, and in seven patients this was severe enough to interfere with their ability to work.

Pulmonary angiotensin II production in respiratory failure.

Plasma angiotensin II concentration gradients across the pulmonary vascular bed, plasma renin concentration and serum converting enzyme activity were measured in 19 patients. The majority of the patients were critically ill. Nine patients had septicemia with acute respiratory failure, six patients had severe chronic lung disease and four patients had other serious disorders requiring haemodynamic monitoring. Pulmonary angiotensin II generation rates were calculated as the products of the pulmonary plasma flow and the angiotensin II concentration gradient across the lung. Several patients had a highly activated renin-angiotensin system. There was a strictly linear correlation between the plasma angiotensin II concentrations in mixed venous blood and in systemic arterial blood across a wide range, the concentration in arterial blood being 1.4-1.5 times that in mixed venous blood in each of the three groups of patients. Serum converting enzyme activity was not different from the level observed in a group of control patients above 50 years of age, but lower than in younger normal individuals. The maximal angiotensin II production rates in the pulmonary vascular bed of patients with life-endangering pulmonary disease were similar to the rates previously measured in hypertensive patients with renovascular or renal parenchymal disease. In conclusion, the process of angiotensin I conversion in the lung operates without impediment in spite of severe pulmonary injury.

Effects of low-dose ketamine and thiopentone on cardiac performance and myocardial oxygen balance in high-risk patients.

Induction of anaesthesia may pose a significant hazard to patients with critical cardiovascular status. Ketamine has been advocated as the drug of choice for maintaining cardiovascular performance during induction of anaesthesia in severely ill surgical patients. The purpose of this study was to compare the relative changes in the haemodynamic effects of ketamine and thiopentone during the first 30 min of anaesthesia induction measured by thoracic impedance cardiography. Twelve adult high-risk surgical patients, ASA class III-V, were induced with thiopentone and fentanyl or with infusion of ketamine. Cardiac output decreased to 69% in the thiopentone group (P less than 0.05), but was hardly affected in the ketamine group. The pre-ejection period to left ventricular time (PEPI) and the pre-ejection period index ratio increased significantly after thiopentone (P less than 0.05), while ketamine caused only minimal changes in left ventricular performance. The diastolic pressure time index to systolic pressure time index ration decreased significantly in both groups.

A new mode of administration of nebulized bronchodilator in severe bronchospasm.

We studied the effect of adding positive end expiratory pressure, PEEP, during the administration of a nebulized bronchodilator in eight patients with acute respiratory failure and severe bronchospasm. Respiratory failure was diagnosed by means of an arterial blood gas analysis and bronchospasm by the presence of wheezing, dyspnea, cough and a forced expiratory volume in the first second, FEV1, of less than 0.7 L. A randomized cross over design was used, where each patient was subjected to two PEEP treatments and two control treatments with zero end expiratory pressure, ZEEP. The interval between each treatment was three hours. With ZEEP, FEV1 rose from 0.69 +/- 0.31 to 1.03 +/- 0.23 L and with PEEP from 0.66 +/- 0.28 to 1.50 +/- 0.48 L (P less than 0.05). Similar changes were seen in forced vital capacity and in peak flow. These results demonstrate that PEEP improves the efficacy of an inhaled, nebulized bronchodilator. This effect is probably mediated through a better distribution especially in peripheral airways.

Dilatation of the trachea treated with the NL-tracheostomy tube.

The NL-tracheostomy tube has a large diameter, large residual volume cuff with automatic and instant cuff pressure regulation. It has been shown in clinical studies to prevent mucosal damage; and depending on airway pressure, it should in theory prevent or delay the onset of trachea dilatation. The authors report 2 patients who developed severe tracheal dilatation with use of standard low volume cuffs during prolonged mechanical ventilation. Placement of the NL-tracheostomy tube with a special long intratracheal leg and cuff positioned below the dilatation abolished the acute problems of air leakage. Tracheal dilatation at the new cuff site did not develop in 1 patient and was slowed in onset in the 2nd patient, who needed high inflation pressures.