Propofol-induced hyperamylasaemia in a general intensive care unit

This study examined the incidence of hyperamylasaemia, in the absence of other plausible causes of pancreatic dysfunction, in intensive care unit (ICU) patients who received propofol. One-hundred-and-seventy-two consecutive patients of a general ICU who stayed for more than 24 hours were studied. Patients with a diagnosis consistent with elevated serum amylase levels at admission were excluded from the study, as were patients who had received medications known to raise serum amylase levels. Forty-four patients 53 +/- 20 years of age and median duration of ICU stay of five days (range two to 55) were eligible. Thirty of those, aged 54 +/- 21 years and median duration of ICU stay of five days (range two to 27) received continuous infusion of propofol for sedation (maximum dose 45 microg/kg/min). Of the 30 patients who received propofol, 16 (53%) developed hyperamylasaemia (125 to 466 IU/l) after two to nine days of continuous infusion. Liver and kidney function remained normal throughout the observation period. Of the 14 patients who did not receive propofol (aged 51 +/- 18 years), only two (14%) developed hyperamylasaemia, a significantly lower incidence (P = 0.021). Propofol infusion is associated with biochemical evidence of pancreatic injury. Amylase levels monitoring of propofol-sedated patients is warranted.

Prolonged use of carbapenems and colistin predisposes to ventilator-associated pneumonia by pandrug-resistant Pseudomonas aeruginosa

OBJECTIVE

We present our experience with five cases of pandrug-resistant Pseudomonas aeruginosa ventilator-associated pneumonia (VAP) and analysis of risk factors.

DESIGN AND SETTING

Case-control study in a 15-bed intensive care unit (ICU).

PATIENTS AND PARTICIPANTS

The study included 5 cases and 20 controls. Each case patient was matched to four contemporary controls according to gender, prior hospital admissions, hospitalization duration, ICU admission cause, Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Function Assessment (SOFA) scores on ICU admission, and length of ICU stay, and mechanical ventilation duration until first VAP episode by a multidrug-resistant bacterium.

MEASUREMENTS AND RESULTS

Recorded variables included age, gender, daily APACHE II and SOFA scores, patient medication, treatment interventions, positive cultures and corresponding antibiograms, occurrence of infection, sepsis, and septic shock, other ICU-associated morbidity, length of ICU stay and mechanical ventilation, and patient outcome. Healthcare worker and environmental cultures, and a hand-disinfection survey were performed. Pandrug-resistant P. aeruginosa isolates belonged to the same genotype and were bla (VIM-1)-like gene positive. The outbreak resolved following reinforcement of infection-control measures (September 27). The sole independent predictor for pandrug-resistant P. aeruginosa VAP was combined use of carbapenem for more than 20 days and colistin use for and more than 13 days (odds ratio 76.0; 95% confidence interval 3.7-1487.6). An additional risk factor was more than 78 open suctioning procedures during 6-26 September (odds ratio 16.0; 95% confidence interval 1.4-185.4).

CONCLUSIONS

Prolonged carbapenem-colistin use predisposes to VAP by pandrug-resistant P. aeruginosa. Cross-transmission may be facilitated by open suctioning.

Pulmonary function at peak exercise in patients with chronic heart failure

BACKGROUND

Various respiratory abnormalities are associated with chronic heart failure (CHF). However, changes in inspiratory capacity (IC) and breathing pattern from rest to exercise in patients with CHF have not been thoroughly investigated in these patients.

MATERIALS AND METHODS

Seventy seven (66 male/11 female) patients with clinical stable CHF (age: 52+/-11 years) were studied. All the patients underwent pulmonary function tests, including measurements of IC and maximal inspiratory pressure (Pimax) at rest and then a maximal cardiopulmonary exercise testing (CPET) on a treadmill. During the CPET, IC was measured every 2 min. Pimax was measured again after the end of CPET.

RESULTS

Percent predicted forced expiratory volume in 1 s (FEV1) was 91+/-12, %predicted forced vital capacity (FVC) was 92+/-13, %FEV1/FVC was 81+/-4, and %predicted IC was 85+/-18. Peak exercise IC was lower than resting (2.4+/-0.6 vs. 2.6+/-0.6 l, p<0.001). Analysis of variance between Weber's groups revealed statistically significant differences in peak exercise IC (p<0.001), VE/VCO2slope (p<0.001), resting Pimax (p=0.005) and post-exercise Pimax (p<0.001). At rest, there was a statistically significant difference in end-tidal CO2 (P(ETCO2)) (p=0.002), in breathing frequency (p=0.004), in inspiratory time (Ti) (p=0.04) and in total respiratory time (T(Tot)) (p=0.004) among Weber's groups. At peak exercise there was a statistically significant decrease in minute ventilation (VE) (p<0.001), tidal volume (VT) (p<0.001), respiratory cycle (VT/TI) (p<0.001) and P(ETCO2) (p<0.001). Peak IC was correlated with peak VO2 (r=0.72, p<0.001), anaerobic threshold (r=0.71, p<0.001), VO2/t slope (r=0.54, p<0.0001), and post-exercise Pimax (r=0.62, p<0.001).

CONCLUSIONS

In patients with CHF, peak exercise IC is reduced in parallel with disease severity, which is probably due to respiratory muscle dysfunction.

Acute Effects of Smoking on Skeletal Muscle Microcirculation Monitored by Near-Infrared Spectroscopy

BACKGROUND

Cigarette smoking predisposes to vascular disease. Our study aimed to assess the acute effects of cigarette smoking on peripheral microcirculation using near-infrared spectroscopy (NIRS) and to compare microcirculatory function of smokers with that of nonsmokers.

METHODS

We examined 65 healthy volunteers: 25 smokers (14 men and 11 women; age range, 20 to 27 years) and 40 nonsmokers (31 men and 9 women; age range, 19 to 38 years). Smokers had refrained from smoking for 2 h prior to the examination. Tissue O(2) saturation (Sto(2)), defined as the percentage of hemoglobin saturation in the microvasculature compartments, was measured with a probe placed on the thenar muscle. Sto(2) baseline values were recorded for 5 min. Subsequently, the brachial artery occlusion technique was applied to evaluate microcirculatory function before, during, and after smoking one cigarette.

RESULTS

Sto(2) before smoking was 85 +/- 6% (mean +/- SD), not differing significantly between men and women (84.4 +/- 6.6% vs 85.6 +/- 5.8%, respectively; p = 0.721). Sto(2) did not change significantly during smoking. O(2) consumption rate was significantly greater in women (33.4 +/- 6.7 Sto(2) U/min vs 25.7 +/- 7.1 Sto(2) U/min, p = 0.032) at baseline and throughout the smoking session. O(2) consumption rate was reduced during smoking (p < 0.001) and at 5 min after the smoking session. Smoking had a significant effect on vascular reactivity (p = 0.015), with no significant differences between genders. Five minutes after smoking, vascular reactivity had returned to approximately normal levels.

CONCLUSION

Smoking acutely affects microcirculatory function. NIRS is a noninvasive, operator-independent technique that can document these effects. It seems promising for the prospective evaluation of the effects of long-term exposure to cigarette smoke.

The effects of exercise training on the kinetics of oxygen uptake in patients with chronic heart failure

BACKGROUND

Prolonged oxygen uptake kinetics (O2 kinetics), following the onset of a constant workload of exercise has been associated with a poor prognosis in patients with chronic heart failure. This study aimed to determine both continuous and interval training effects on the different O2-kinetics phases in these patients.

DESIGN

Twenty-one patients (60+/-8 years) with stable chronic heart failure participated in a 36-session exercise rehabilitation program (three times weekly). Patients were randomly assigned to interval training (n=11; 100% of peak work rate for 30 s, alternating with 30 s-rest) and to continuous training (n=10; 50% of peak work rate).

METHODS

Before and after the completion of the program, all patients performed both incremental symptom-limited and constant workload submaximal cardiopulmonary exercise tests. Phase I O2-kinetics was evaluated by time (t), from the start of exercise until the onset of decreased respiratory exchange ratio and phase II by the time constant (tau) of the response from the end of phase I until steady state.

RESULTS

After training, there was a significant increase in peak oxygen uptake and peak work rate in both continuous (15.3+/-4.4 vs. 16.6+/-4.5 ml/kg per min; P=0.03 and 81.8+/-40.1 vs. 94.7+/-46.1 W; P=0.03) and interval training groups (14.2+/-3.1 vs. 15.4+/-4.2 ml/kg per min; P=0.03 and 82.5+/-24.1 vs. 93.7+/-30.1 W; P=0.04). Patients who underwent interval training had a significant decrease in t (39.7+/-3.7 to 36.1+/-6.9 s; P=0.05), but not tau (59.6+/-9.4 to 58.9+/-8.5 s; P=ns), whereas those assigned to continuous training had a significant decrease in both t (40.6+/-6.1 to 36.4+/-5.4 s; P=0.01) and tau (63.3+/-23.6 to 42.5+/-16.7 s; P=0.03).

CONCLUSIONS

Exercise training improves O2 kinetics in chronic heart failure patients. Both continuous and interval training improve phase I O2-kinetics, but continuous training results in superior improvement of the phase II O2-kinetics, an indirect index of muscle oxidative capacity.

The effects of exercise training on the kinetics of oxygen uptake in patients with chronic heart failure

BACKGROUND

Prolonged oxygen uptake kinetics (O2 kinetics), following the onset of a constant workload of exercise has been associated with a poor prognosis in patients with chronic heart failure. This study aimed to determine both continuous and interval training effects on the different O2-kinetics phases in these patients.

DESIGN

Twenty-one patients (60+/-8 years) with stable chronic heart failure participated in a 36-session exercise rehabilitation program (three times weekly). Patients were randomly assigned to interval training (n=11; 100% of peak work rate for 30 s, alternating with 30 s-rest) and to continuous training (n=10; 50% of peak work rate).

METHODS

Before and after the completion of the program, all patients performed both incremental symptom-limited and constant workload submaximal cardiopulmonary exercise tests. Phase I O2-kinetics was evaluated by time (t), from the start of exercise until the onset of decreased respiratory exchange ratio and phase II by the time constant (tau) of the response from the end of phase I until steady state.

RESULTS

After training, there was a significant increase in peak oxygen uptake and peak work rate in both continuous (15.3+/-4.4 vs. 16.6+/-4.5 ml/kg per min; P=0.03 and 81.8+/-40.1 vs. 94.7+/-46.1 W; P=0.03) and interval training groups (14.2+/-3.1 vs. 15.4+/-4.2 ml/kg per min; P=0.03 and 82.5+/-24.1 vs. 93.7+/-30.1 W; P=0.04). Patients who underwent interval training had a significant decrease in t (39.7+/-3.7 to 36.1+/-6.9 s; P=0.05), but not tau (59.6+/-9.4 to 58.9+/-8.5 s; P=ns), whereas those assigned to continuous training had a significant decrease in both t (40.6+/-6.1 to 36.4+/-5.4 s; P=0.01) and tau (63.3+/-23.6 to 42.5+/-16.7 s; P=0.03).

CONCLUSIONS

Exercise training improves O2 kinetics in chronic heart failure patients. Both continuous and interval training improve phase I O2-kinetics, but continuous training results in superior improvement of the phase II O2-kinetics, an indirect index of muscle oxidative capacity.

Early heart rate recovery after exercise predicts mortality in patients with chronic heart failure

BACKGROUND

Patients with chronic heart failure (CHF) have multiple abnormalities of autonomic regulation that have been associated to their high mortality rate. Heart rate recovery immediately after exercise is an index of parasympathetic activity, but its prognostic role in CHF patients has not been determined yet.

METHODS

Ninety-two stable CHF patients (83M/9F, mean age: 51+/-12 years) performed an incremental symptom-limited cardiopulmonary exercise testing. Measurements included peak O2 uptake (VO2p), ventilatory response to exercise (VE/VCO2 slope), the first-degree slope of VO2 for the 1st minute of recovery (VO2/t-slope), heart rate recovery [(HRR1, bpm): HR difference from peak to 1 min after exercise] and chronotropic response to exercise [%chronotropic reserve (CR, %)=(peak HR-resting HR/220-age-resting HR)x100]. Left ventricular ejection fraction (LVEF, %) was also measured by radionuclide ventriculography.

RESULTS

Fatal events occurred in 24 patients (26%) during 21+/-6 months of follow-up. HRR1 was lower in non-survivors (11.4+/-6.4 vs. 20.4+/-8.1; p<0.001). All cause-mortality rate was 65% in patients with HRR1<or=12 bpm versus 11% in patients with HRR1>12 bpm (log-rank: 32.6; p<0.001). By multivariate survival analysis, HRR1 resulted as an independent predictor of mortality (chi2=19.2; odds ratio: 0.87; p<0.001) after adjustment for LVEF, VO2p, VE/VCO2 slope, CR and VO2/t-slope. In a subgroup of patients with intermediate exercise capacity (VO2p: 10-18, ml/kg/min), HRR1 was a strong predictor of mortality (chi2: 14.3; odds ratio: 0.8; p<0.001).

CONCLUSIONS

Early heart rate recovery is an independent prognostic risk indicator in CHF patients and could be used in CHF risk stratification.

Effects of exercise rehabilitation program on heart rate recovery in patients with chronic heart failure

BACKGROUND

Heart rate recovery (HRR1) immediately after exercise reflects parasympathetic activity, which is markedly attenuated in chronic heart failure (CHF) patients. The aim of our study was to examine both continuous and interval exercise training effects on HRR1 in these patients.

DESIGN

The population study consisted of 29 stable CHF patients that participated at a rehabilitation program of 36 sessions, three times per week. Of the 29 patients, 24 completed the program. Patients were randomly assigned to interval {n=10 [100% peak work rate (WRp) for 30 s, alternating with rest for 30 s]} and to continuous training [n=14 (50%WRp)].

METHODS

All patients performed a symptom-limited cardiopulmonary exercise test on a cycle ergometer before and after the completion of the program. Measurements included peak oxygen uptake (VO2p), anaerobic threshold (AT), WRp, first degree slope of VO2 during the first minute of recovery (VO2/t-slope), chronotropic response [% chronotropic reserve (CR)=(peak HR - resting HR)x100/(220 - age - resting HR)], HRR1 (HR difference from peak exercise to one minute after).

RESULTS

After the completion of the rehabilitation program there was a significant increase of WRp, VO2p, AT and VO2/t-slope (by 30%, P=0.01; 6%, P=0.01; 10%, P=0.02; and 27%, P=0.03 respectively for continuous training and by 21%, P<0.05; 8%, P=0.01; 6%, P=NS; and 48%, P=0.02 respectively for interval training). However, only patients exercised under the continuous training regime had a significant increase in HRR1 (15.0+/-9.0 to 24.0+/-12 bpm; P=0.02) and CR (57+/-19 to 72+/-21%, P=0.02), in contrast with those assigned to interval training (HRR1: 21+/-11 to 21+/-8 bpm; P=NS and CR: 57+/-18 to 59+/-21%, P=NS).

CONCLUSIONS

Both continuous and interval exercise training program improves exercise capacity in CHF patients. However, continuous rather than interval exercise training improves early HRR1, a marker of parasympathetic activity, suggesting a greater contribution to the autonomic nervous system.

Patterns of dynamic hyperinflation during exercise and recovery in patients with severe chronic obstructive pulmonary disease

BACKGROUND

Not all patients with severe chronic obstructive pulmonary disease (COPD) progressively hyperinflate during symptom limited exercise. The pattern of change in chest wall volumes (Vcw) was investigated in patients with severe COPD who progressively hyperinflate during exercise and those who do not.

METHODS

Twenty patients with forced expiratory volume in 1 second (FEV(1)) 35 (2)% predicted were studied during a ramp incremental cycling test to the limit of tolerance (Wpeak). Changes in Vcw at the end of expiration (EEVcw), end of inspiration (EIVcw), and at total lung capacity (TLCVcw) were computed by optoelectronic plethysmography (OEP) during exercise and recovery.

RESULTS

Two significantly different patterns of change in EEVcw were observed during exercise. Twelve patients had a progressive significant increase in EEVcw during exercise (early hyperinflators, EH) amounting to 750 (90) ml at Wpeak. In contrast, in all eight remaining patients EEVcw remained unchanged up to 66% Wpeak but increased significantly by 210 (80) ml at Wpeak (late hyperinflators, LH). Although at the limit of tolerance the increase in EEVcw was significantly greater in EH, both groups reached similar Wpeak and breathed with a tidal EIVcw that closely approached TLCVcw (EIVcw/TLCVcw 93 (1)% and 93 (3)%, respectively). EEVcw was increased by 254 (130) ml above baseline 3 minutes after exercise only in EH.

CONCLUSIONS

Patients with severe COPD exhibit two patterns during exercise: early and late hyperinflation. In those who hyperinflate early, it may take several minutes before the hyperinflation is fully reversed after termination of exercise.