The water channel AQP1 is expressed in human atherosclerotic vascular lesions and AQP1 deficiency augments angiotensin II-induced atherosclerosis in mice.

AIM: The water channel aquaporin 1 (AQP1) promotes endothelial cell migration. It was hypothesized that AQP1 promotes neovascularization and growth of atherosclerotic plaques. METHODS: AQP1 immunoreactivity and protein abundance was examined in human and murine atherosclerotic lesions and aortic aneurysms. Apolipoprotein E (ApoE) knockout (-/-) and AQP1-/-ApoE-/- mice were developed and fed Western diet (WD) for 8 and 16 weeks to accelerate the atherosclerosis process. In ApoE-/- and AQP1-/-ApoE-/- mice abdominal aortic aneurysms (AAA) were induced by angiotensin II (ANGII) infusion by osmotic minipumps for 4 weeks. RESULTS: In human atherosclerotic lesions and AAA, AQP1 immunoreactive protein was associated with intralesional small vessels. In ApoE-/- mouse aorta, APQ1 mRNA levels were increased with time on WD (n = 7-9, P < 0.003). Both in murine lesions at the aortic root and in the abdominal aortic aneurysmal wall, AQP1 immunoreactivity was associated with microvascular structures. The atherosclerotic lesion burden was enhanced significantly in ANGII-infused AQP1-/-ApoE-/- mice compared with ApoE-/- mice, but neither incidence nor progression of AAA was different. The aortic lesion burden increased with time on WD but was not different between ApoE-/- and AQP1-/-ApoE-/- mice at either 8 or 16 weeks (n = 13-15). Baseline blood pressure and ANGII-induced hypertension were not different between genotypes. CONCLUSION: AQP1 is expressed in atherosclerotic lesion neovasculature in human and mouse arteries and AQP1 deficiency augments lesion development in ANGII-promoted atherosclerosis in mice. Normal function of AQP1 affords cardiovascular protection.

Perioperative monitoring with pulse oximetry and late postoperative cognitive dysfunction.

In a randomized, blinded clinical study, we have used objective and subjective measures to determine if perioperative monitoring with pulse oximetry--by virtue of its potential to lessen hypoxaemia--would decrease late postoperative cognitive dysfunction. We investigated 736 adult patients undergoing elective procedures (other than cardiac, neurosurgical or for cancer) under regional or general anaesthesia, allocated randomly to undergo (group I) or not to undergo (group II) pulse oximetry monitoring in the operating theatre and recovery room. Cognitive function was evaluated using the Wechsler memory scale (WMS) and continuous reaction time (RT) test the day before surgery, and on the 7th day after operation or at discharge if that occurred before postoperative day 7. A questionnaire sent 6 weeks after surgery elicited patients' subjective perceptions regarding cognitive abilities. There were no significant differences between the two groups in either the total WMS score, the score for each WMS subtests or RT test. The questionnaire revealed that 7% in group I and 11% in group II believed cognitive abilities had decreased (ns). For the 40 patients whose WMS scores were 10 points less after than before operation, a follow-up study was undertaken 3 months after surgery. At that time, the median WMS score had returned to the preoperative value. We conclude that, for these 736 patients, subjective and objective measures did not indicate less postoperative cognitive impairment after perioperative monitoring with pulse oximetry.

Hypoxemia in the postanesthesia care unit: an observer study.

To determine the incidence and duration of hypoxemia in the postanesthesia care unit (PACU), 200 patients were investigated in a single-blind observer study. The number of unrecognized hypoxemic episodes, as well as risk factors and possible association between hypoxemia and postoperative morbidity, were studied. Oxygenation was monitored continuously with a pulse oximeter. One or more hypoxemic episodes (SpO2 less than or equal to 90%) were noted in 55% of the patients. SpO2 values less than or equal to 80% were noted in 13% of the patients. Supplementary oxygen was given during 55% of the 447 hypoxemic episodes registered. The hypoxemic episodes were unrecognized by the staff in 95% of the cases. With stepwise multiple logistic regression analyses, risk factors associated with a higher incidence of hypoxemia were: duration of anesthesia (P less than 0.0001), age (P less than 0.002) and a history of smoking (P less than 0.01). Patients who had undergone regional anesthesia had a lower risk of hypoxemia (P less than 0.0002). The occurrence of hypoxemia in the PACU could not be correlated to postoperative morbidity. We conclude that hypoxemic episodes in our PACU are common and that the routine use of supplemental oxygen combined with normal clinical surveillance did not prevent hypoxemic episodes.

[Monitoring routines at Danish anesthesia departments]. / Monitoreringspraksis på danske anaestesiafdelinger.

By means of a questionnaire investigation, 84 Danish anaesthetic departments were questioned in January 1987 about their monitoring routines during anaesthesia and recovery. 100% replied. The investigation revealed that measurement of the blood pressure in adults was the routine in all of the departments. Patients were monitored routinely with EGG in 62 departments where minor surgical interventions were concerned while, in major surgical intervention, ECG monitoring was the routine in 91% of the departments. Patients were observed postoperatively in the recovery room or intensive care unit in 51% of the departments. The questionnaire investigation revealed great variation in the monitoring and supervision routines in the anaesthetic departments in Denmark. Hitherto, it has not been possible to demonstrate that monitoring of the functions of vital organs in operation patients can reduce the morbidity and mortality connected with the anaesthesia. It is concluded that it would be desirable to carry out clinically controlled investigations to illustrate whether monitoring equipment can reduce the morbidity connected with anaesthesia and to develop a Danish recommendation concerning peroperative monitoring and postoperative observation.

Serious morbidity attributable to anaesthesia. Considerations for prevention.

The types and frequency of complications attributable solely to anaesthesia, and which caused serious morbidity and substantial negative outcome, were examined in a prospective study of 7306 anaesthetics. The analysis demonstrated that severe complications and mortality attributable to anaesthesia occurred in 0.59% (1:170) and 0.04% (1:2500) of patients respectively. The data suggest that "high-risk' patients are more likely to be affected by errors and a substantial negative outcome than more healthy patients. We judged one-third of the anaesthesia-related morbidity to be preventable. Anaesthetists are faced with an increasing number of patients who are at high risk, and who undergo increasingly extensive surgical interventions. Concomitant with the increasing complexity of care and increasing demands on the anaesthetists may be an expected increase in the incidence of errors. Recognition of the importance of human factors in morbidity and mortality attributable to anaesthesia is a necessary first step.

Risk factors, complications and outcome in anaesthesia. A pilot study.

In a screening study the strength of association between individual risk factors and post-operative outcome was examined using three-dimensional variate analyses. In a study of 1016 patients, the incidence of life-threatening complications during anaesthesia was low (0.2%), whereas minor complications were seen in about 6% of the patients. Opiate overdose or residual curarization occurred in almost 2% of the cases. One hundred and eleven variables were prospectively assessed and 35 pre-operative variables were evaluated for their possible relationship to one event: post-operative mechanical ventilation (MV). The statistical method suggested that seven of the pre-operative variables seemed to be associated with post-operative MV. Eleven out of 20 patients with respiratory failure who were treated with MV died after anaesthesia (55%) compared with the overall hospital mortality of 2.7%.

Resistive breathing training in severe chronic obstructive pulmonary disease. A pilot study.

We studied the effects of resistive breathing in 10 patients with long-standing, severe disabling COPD. Small increases in inspiratory resistive load resulted in diaphragmatic fatigue and failure in all patients. Fatigue was detected using the frequency spectrum analysis of an EMG signal obtained with surface electrodes. Failure was defined as an inward displacement of the abdomen during inspiration, i.e. incoordination of thoracoabdominal motion. The patients trained for one half hour daily for 4 weeks, breathing into a simple device, where they inspired against a resistive load that produced some incoordinated breaths. After 4 weeks this load was increased, if possible, and another 4-week training period started. All patients improved with training, i.e. higher resistances could be tolerated without signs of fatigue and failure. In addition most patients claimed that training had helped them in their daily living; they were able to do more without getting short of breath. The device helped expectoration, possibly owing to the effect of the small expiratory resistance.