Effect of intraoperative fluid administration and colloid osmotic pressure on the formation of intestinal edema during gastrointestinal surgery

The effects of intraoperative changes in plasma colloid osmotic pressure (COP) on the formation of intestinal edema were studied in patients during modified Whipple's operation (hemipancreato-duodenectomy). Eighteen patients (ASA physical status I or II) were randomly assigned to one of three groups. They received either lactated Ringer's (RL group, n = 6), 10% hydroxyethyl starch (HES group, n = 6), or 20% human albumin (HA group, n = 6) as a volume replacement solution, which was given to maintain central venous pressure (CVP) at the preoperative level. Jejunal specimens were obtained after the first transsection of the jejunum and prior to the jejuno-jejunostomy. Their water fraction (g H2O/g tissue dry weight) was measured gravimetrically. COP was determined prior to induction of anesthesia and upon removal of the second jejunal sample. In the RL group, 3,850 +/- 584 ml (data are means +/- SEM) of volume replacement solution were infused from induction of anesthesia to removal of the second jejunal sample. In the HES group, 1,358 +/- 45 ml were infused, and in the HA group, 463 +/- 49 ml were infused. During this time, COP decreased from 20.3 +/- 0.5 mmHg to 14.1 +/- 0.6 mmHg in the RL group, remained at 22.0 +/- 0.9 mmHg in the HES group, and increased from 20.7 +/- 0.9 mmHg to 28.1 +/- 0.9 mmHg in the HA group.(ABSTRACT TRUNCATED AT 250 WORDS)

[Inhalation anesthesia with halogenated hydrocarbons: value of isoflurane]

The halogenated hydrocarbons halothane, enflurane and isoflurane are used extensively. Like every other anaesthetic, these inhaled agents are not devoid of side effects, most of which are undesirable. This review summarises the similarities and differences between the actions of these vapours. Although isoflurane appears to be more advantageous than enflurane and halothane in certain patients, isoflurane is no panacea and the question of which agent to choose still has to be answered for every patient. A note of caution is warranted against the further use of halothane in adults, as halothane offers no advantages when compared to enflurane and isoflurane but carries a higher risk of hepatotoxicity. However, in children halothane remains the halogenated agent of first choice, when anaesthesia is induced via face mask.

Infection surveillance and selective decontamination of the digestive tract (SDD) in critically ill patients--results of a controlled study

All ICU patients were continuously monitored for infections according to a standard protocol by the physician in charge and an infection control nurse during the first quarter of five consecutive years (1980-1984). The number of patients surveyed was 1,009. The average age was 45.5 years and the average period of stay about four days. 733 patients (72.6%) were intubated and artificially ventilated for three days. A fatal outcome resulted in 13.2% of all patients, 1,129 nosocomial infections were registered in 331 patients, which means an infection rate of 32.8%. The most frequent nosocomial infections were those of the respiratory tract (24.3%). Wound infections developed in 16.6%. The urinary tract was affected in 8.8%. Nosocomial septicaemias were observed in 8.7%. Catheter-associated infections were found in 6.7% of the patients. A fatal outcome resulted in 26% of the patients with nosocomial infections and in 6.9% of the non-infected patients, respectively. There was no significant reduction in nosocomial infections over the five-year period in our ICU. Therefore, a study was designed to evaluate the concept of selective decontamination of the digestive tract (SDD) in critically ill patients in our two surgical/traumatological ICUs. A prospective, consecutive, placebo-controlled study in two ICUs was carried out during four six-month periods. 200 patients who were intubated for at least three days, required intensive care for a minimum of five days, and belonged to either class III or IV according to the "Therapeutic Intervention Scoring System" were included in the study. They received either placebo or a prophylaxis regimen, consisting of polymyxin E, tobramycin and amphotericin B.(ABSTRACT TRUNCATED AT 250 WORDS)

[High-frequency ventilation: side effects and dangers]

Dangers of high-frequency ventilation result from the lack of a sensitive monitoring technique. Mucosal lesions of the trachea and the bronchi as well as cooling of the patient can be prevented by adequate humidification and heating of the gas flow. It is still controversial whether HFV leads to increased mucus production or secretolysis, and whether it prevents or promotes aspiration. The influence of mobilisation or immobilisation of a pulmonary focus on its recovery is not well understood. Interferences of HFV with the autonomic nervous system and endocrine system, like an increased release of PGI2, an antidiuretic and narcotic effect, with the coagulation system and the acid-base balance are inconsistent and therefore need particular clinical observation.

[Selective flora suppression for control of infection in surgical intensive care medicine]

The question to be answered in this study was: Is prophylactic selective florasuppression advantageous compared to conventional antibiotic policy as far as microbial colonisation, infection, mortality and development of resistance are concerned? A prospective, consecutive, placebo-controlled study in two ICU's was carried out during four 6-months periods. 200 patients who were intubated for at least 3 days, required intensive care for a minimum of 5 days, and belonged to either class III or IV according to the "Therapeutic Intervention Scoring System" were included in the study. They received either placebo or the prophylaxis regimen described by Stoutenbeek et al., consisting of polymyxin E, tobramycin and amphotericin B. Oropharyngeal, tracheobronchial and rectal colonisation with aerobic gram-negative bacilli markedly decreased in the test groups. The rates of nosocomial bronchopulmonary infections (ICU I and II) and urinary tract infections (ICU II) were significantly reduced. There was no significant reduction in wound infection, septicaemia and mortality rates. No development of resistance and no increase of multi-resistant strains occurred. Selective florasuppression is effective in reducing infection rates in critically ill patients without development of resistant strains.

[Psychophysiologic reaction patterns in coping with events by intensive care patients]

The aim of this study was to demonstrate the clear relations between psychological and physiological parameters determined in intensive care patients. For this purpose, heart rate, salivary-cortisol secretion and blood pressure were measured as physiological stress indicators; psychological parameters were covered by examining the patients' way of coping, that is to contrast emotional with rational coping. By comparison, the equivalent parameters were determined in a group of healthy patients. When comparing both groups, we found a higher salivary-cortisol secretion and an increased heart rate in the group of intensive care patients, with the circadian rhythm of the cortisol-secretion remaining almost stable. When examining the patients' group according to the way of coping, we found a higher activation of the sympathetic nervous system in those patients who coped with their situation emotionally than in those who faced their problems rationally. The level of physiological excitation significantly decreased after the patients had been transferred from the ICU to the normal ward. The increased physiological excitation of ICU patients serves to release energies that help them to cope with their situation and can likewise be associated with emotional reactions such as being extremely watchful and in a state of mobilization as well as feeling particularly helpless. The extent of physiological irritation is modified by the way of intrapsychical coping.

Constant-flow ventilation in canine experimental pulmonary emphysema

The efficacy of constant-flow ventilation (CFV) was investigated in eight mongrel dogs before (control-phase) and after development of papain-induced panlobular emphysema (PLE-phase). For CFV, heated, humidified and oxygen-enriched air was continuously delivered via two catheters positioned within each mainstem bronchus at flow rates (V) of 0.33, 0.5 and 0.66 l/s. Data obtained during intermittent positive pressure ventilation (IPPV) served as reference. In the control-phase, Pao2 was lower (P less than or equal to 0.05) and alveolo-arterial O2 difference (P(A-a)O2) was higher (P less than or equal to 0.01) during CFV at all flow rates when compared with IPPV. This may be due to inhomogeneities of intrapulmonary gas distribution and increased ventilation-perfusion (VA/Q) mismatching. Paco2 and V showed a hyperbolic relationship; constant normocapnia (5.3 kPa) was achieved at 0.48 +/- 0.21 l/s (V53). Development of PLE resulted in an increase of functional residual capacity (FRC), residual volume (RV) and static compliance (Cstat) (P less than or equal to 0.05). PaO2 had decreased and P(A-a)O2 had increased (P less than or equal to 0.05), indicating moderate pulmonary dysfunction. Oxygenation during CFV was not significantly different in the PLE-phase when compared with the control-phase. Paco2 and V showed a hyperbolic relationship and V5.3 was even lower than in the control-group (0.42 +/- 0.13 l/s). In dogs with emphysematous lungs CFV maintains sufficient gas exchange. This may be due to preferential ventilation of basal lung units, thereby counterbalancing the effects of impaired lung morphometry and increased airtrapping. Conventional mechanical ventilation is more effective in terms of oxygenation and CO2-elimination.

Hemodynamic and cardiodynamic effects of propofol and etomidate: negative inotropic properties of propofol

The hemodynamic effects of an induction dose of propofol, 2.5 mg/kg, or etomidate, 0.3 mg/kg, were studied in eight dogs. In addition, cardiodynamic changes were measured using a left ventricular catheter and needle force probes. Propofol was associated with significant decreases in systolic (19.9%) and diastolic (25.3%) arterial pressures associated with a 17.3% decrease in cardiac output (CO) and a 11.6% reduction in systemic vascular resistance (SVR) without change in pulmonary capillary wedge pressure (PCWP). These changes were most pronounced 1 min after the injection of propofol. At 5 and 10 min after the administration of propofol, heart rate (HR) decreased significantly. Minimal changes in hemodynamics were observed with etomidate. Propofol lowered systolic left ventricular pressure (LVPsys) by 17.6%. Signals generated by the force probes in the left ventricular myocardium showed a significant reduction (16.3%) in left ventricular force (LVF) and a decrease in early systolic rates of increase in force (dF/dt max) by 23.5% associated with propofol. In the presence of an unchanged preload, an unchanged HR, and a decreased SVR, the reduction in CO suggests that propofol has a negative inotropic effect. This negative inotropic effect was confirmed by a reduction in LVF and dF/dt max.

Single breath N2 washout in papain-induced pulmonary emphysema

Single breath nitrogen washout tests were analyzed in dogs (n = 8) with healthy lungs and after development of emphysema. The animals were in the supine position and studied during anaesthesia and mechanical ventilation (FiO2 = 0.4, FiN2 = 0.6). During controlled expiration with constant flow (VE = 0.15 l/s) onset of phase IV of the alveolar plateau was related to airway closure of dependent lung regions (closing volume CV). In the control state, CV accounted for 6.2 +/- 1.5% VC, and closing capacity (CC) was lower than functional residual capacity (FRC). Likewise, gas exchange was normal in all animals (PaO2 = 24.7 +/- 3.32 kPa, PaCO2 = 5.18 +/- 0.53 kPa, PA-aO2 = 2.6 +/- 0.3 kPa). Panlobular emphysema (PLE) was induced by inhalation of papain (100 mg/kg). After three weeks development of PLE was documented by measurements of lung volumes (functional residual capacity (FRC), expired vital capacity (EVC), total lung capacity (TLC), residual volume (RV], pulmonary mechanics (dynamic and static compliance (Cdyn, Cstat), mean airway resistance (Raw], gas exchange (PaO2, PaCO2, PA-aO2), and by radiomorphological analysis. In the PLE-group, FRC and RV (p less than or equal to 0.05), and Cstat (p less than or equal to 0.01) were significantly elevated. CV increased to 16.2 +/- 2.7% VC (p less than or equal to 0.01) and CC exceeded FRC by 80 ml, indicating that tidal volume breathing took place within the range of closing volume. Oxygenation was significantly impaired (PaO2 = 18.6 +/- 3.72 kPa, PA-aO2 = 6.5 +/- 1.1 kPa, p less than or equal to 0.05), but not CO2-elimination. Pathological analysis by radiomorphological means showed dissiminate parenchymal lesions compatible with emphysema of grade II severity located predominantly in subpleural areas. In dogs with papain-induced PLE, premature closure of dependent airways is enhanced, which is due to structural changes and a loss of elastic recoil in the lungs.

Effect of parenteral glutamine peptide supplements on muscle glutamine loss and nitrogen balance after major surgery

Twelve patients admitted for elective resection of carcinoma of colon or rectum were allocated at random to experimental and control groups (six in each) and received a total parenteral nutrition regimen providing 230 mg N/kg and 166 KJ/kg daily over the first 5 postoperative days. In the experimental group the parenteral fluid was supplemented with a synthetic glutamine-containing dipeptide, L-alanyl-L-glutamine (54 mg peptide-N/kg per day) and the control group received corresponding amounts of alanine-N and glycine-N. On each postoperative day nitrogen balance was better in the experimental group; mean daily nitrogen balance with alanyl-glutamine was -1.5 (SE 0.4) g N/day and with the control solution -3.6 (0.2) g N/day. The cumulative nitrogen balances on the fifth postoperative day were -7.1 (2.2) and -18.1 (1.7) g N, respectively. With the peptide-containing solution intramuscular glutamine concentration remained close to the preoperative value whereas with the control solution it decreased from 19.7 (SE 0.9) to 12.0 (0.6) mmol/l intracellular water.

High-frequency jet ventilation during oleic-acid induced pulmonary oedema

In oleic acid-induced pulmonary oedema (OAPO) sequential intrapulmonary fluid accumulation occurs leading to different expiratory flow pattern in dependent lung regions. The potential effects on efficacy of high-frequency jet ventilation (HFJV, f = 3 Hz, I: E = 0.43, FiO2 = 0.4) were studied and compared with continuous positive pressure ventilation (CPPV, f = 12-18/min, I:E = 0.5, TV = 12 ml/kg, PEEP = 0.5 kPa, FiO2 = 0.4) in a dog model of OAPO. In the control state (lung-healthy dogs), 15 min after oleic acid lung injury (interstitial oedema, period I) and 60 min after onset of OAPO (alveolar oedema, period II), gas exchange, lung volumes, compliance, resistance and haemodynamics were measured. The course of lung oedema was determined indirectly by means of washout curves of helium (foreign gas bolus-test, FGB) and nitrogen (single breath-test for oxygen, SBO2). During control, there were no significant differences between the HFJV-group (n = 7) and the CPPV-group (n = 6) by virtue of gas exchange, lung volumes and haemodynamics. During period I, PaO2 decreased significantly both with HFJV (p less than 0.01) and CPPV (p less than 0.05), being lower in the HFJV-group (p less than 0.05). PaCO2, pulmonary and haemodynamic parameters were unchanged. Onset of phase IV of the alveolar plateau (closing volume CV) occurred significantly earlier (p less than 0.05) in all animals. Impaired ventilation of dependent lung regions, increased maldistribution of intrapulmonary gas and VA/Q-mismatching may be the underlying mechanisms for lower efficacy of HFJV during interstitial lung oedema. In period II, pulmonary and cardiocirculatory parameters had changed significantly in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential ventilation with low-flow CPAP and CPPV in the treatment of unilateral chest trauma

A case of severe unilateral chest trauma with bronchopleural fistula is presented. Ventilatory therapy consisted of asynchronous independent lung ventilation (AILV). The injured lung was ventilated with intermittent positive pressure ventilation (IPPV) [tidal volume (TV) = 200 ml, f = 25/min, I:E = 0.5, minute volume (MV) = 5.0 l/min, FiO2 = 0.4], and the unaffected lung was ventilated with continuous positive pressure ventilation (CPPV) (TV = 600 ml, f = 12/min, I:E = 0.5, MV = 7.2 l/min, PEEP = 0.5 kPa, FiO2 = 0.4). Adequate gas exchange was obtained (PaO2 = 14.5 +/- 2.3 kPa, PaCO2 = 5.5 +/- 0.7 kPa), but high air leakage volumes persisted. Thus, differential low-flow CPAP (V = 5.0-7.5 l/min, PEEP = 0.5 kPa, FiO2 = 0.4) of the injured lung and CPPV (TV = 600 ml, f = 12/min, MV = 7.2 l/min, I:E = 0.5, PEEP = 0.5 kPa, FiO2 = 0.4) of the unaffected lung was applied for 36 hours. Further deterioration of pulmonary function was prevented, and the bronchopleural fistula closed after several hours. After another period of AILV the patient was treated with conventional mechanical ventilation, and finally weaned with high-flow CPAP.

Permeation of the blood-brain barrier by urapidil and its influence on intracranial pressure in man in the presence of compromised intracranial dynamics

We studied eight patients undergoing craniotomy for intracerebral tumour surgery requiring monitoring of intracranial pressure. All these patients showed significantly increased systolic arterial pressure, during anaesthesia. Following an average dose of 0.8 +/- 0.22 mg/kg urapidil, systolic arterial pressure returned to baseline values without a significant change in intracranial pressure. In nine patients, urapidil concentrations in plasma and cerebrospinal fluid were assayed following an intravenous injection of urapidil. Urapidil was found in the cerebrospinal fluid in concentrations between 5 and 99 ng/ml after total cumulative bolus injections of 10-75 mg. There is evidence that in clinically applied doses urapidil permeates the blood-brain barrier and reaches cerebrospinal fluid concentrations that allow an interaction with central 5-hydroxytryptamine-1A receptors.

[The behavior of intracranial pressure and intracranial compliance in nifedipine-induced hypotension]

The influence of nifedipine induced hypotension on intracranial pressure (ICP) and intracranial compliance (ICC) was investigated in dogs without (group I, n = 8) and with (group II, n = 8) intracranial hypertension. ICP in group II was raised by gradual inflation of an epidurally placed balloon catheter. A volume-pressure-response curve (VPR) was established before and during the administration of nifedipine. In group II dogs angiotensin was infused before and during infusion of nifedipine in a dose sufficient to raise mean arterial pressure (MAP) by 30-40 mm Hg. An infusion of nifedipine (2 micrograms X kg-1 X min-1) subsequent to a bolus injection of nifedipine (10 micrograms X kg-1) resulted in a significant and sustained decrease in MAP (p less than 0.05) by 25% and 35% resp. due to a significant reduction in total peripheral resistance (p less than 0.05). ICP increased from 8.7 +/- 3.0 mm Hg to a maximum of 12.5 +/- 5.2 mm Hg in group I animals (p less than 0.05) and from 19.8 +/- 2.6 mm Hg to 24.8 +/- 7.2 mm Hg not significantly in group II dogs. The pressure-volume-index revealed a slight reduction of ICC in group I and a slight increase of ICC in group II resp. during nifedipine as compared to before nifedipine. When angiotensin was being administered in group II dogs before nifedipine was given, MAP increased by 40 +/- 5.8 mm Hg while ICP did not change significantly (+2 +/- 2.4 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)