Immediate and 5-year cumulative outcome after paediatric intensive care in Sweden.

BACKGROUND: Little has been reported about intensive care of children in Sweden. The aims of this study are to (I) assess the number of admissions, types of diagnoses and length-of-stay (LOS) for all Swedish children admitted to intensive care during the years 1998-2001, and compare paediatric intensive care units (PICUs) with other intensive care units (adult ICUs) (II) assess immediate (ICU) and cumulative 5-year mortality and (III) determine the actual consumption of paediatric intensive care for the defined age group in Sweden. METHODS: Children between 6 months and 16 years of age admitted to intensive care in Sweden were included in a national multicentre, ambidirectional cohort study. In PICUs, data were also collected for infants aged 1-6 months. Survival data were retrieved from the National Files of Registration, 5 years after admission. RESULTS: Eight-thousand sixty-three admissions for a total of 6661 patients were identified, corresponding to an admission rate of 1.59/1000 children per year. Median LOS was 1 day. ICU mortality was 2.1% and cumulative 5-year mortality rate was 5.6%. Forty-four per cent of all admissions were to a PICU. CONCLUSIONS: This study has shown that Sweden has a low immediate ICU mortality, similar in adult ICU and PICU. Patients discharged alive from an ICU had a 20-fold increased mortality risk, compared with a control cohort for the 5-year period. Less than half of the paediatric patients admitted for intensive care in Sweden were cared for in a PICU. Studies are needed to evaluate whether a centralization of paediatric intensive care in Sweden would be beneficial to the paediatric population.

Changes in mean airway pressure during HFOV influences cardiac output in neonates and infants.

BACKGROUND: Changes in mean airway pressure affect cardiac output during conventional positive pressure ventilation. The effect of high-frequency oscillation ventilation (HFOV) on cardiac output is less studied. METHODS: A prospective study in a university hospital pediatric intensive care unit. Fourteen patients aged <1 year and weighing <10 kg who were on HFOV were included. All patients had been on HFOV for >12 h and were considered to be in a stable condition. In the study group (n = 9) the mean proximal airway pressure (Paw) was increased and decreased by +5 and -3 cmH2O, respectively, from baseline in each patient. Measurements were made at each level including baseline settings between each change. In a control group (n = 5) no changes in ventilatory parameters were made. Cardiac output was assessed with echocardiography and the Doppler technique at each level of Paw and at similar intervals in the control group. RESULTS: Cardiac output changed significantly when Paw was changed in the study group (P = 0.02), with the greatest change at the highest Paw at -11% (range: -19 to -9) compared with baseline. We found no significant changes over time in the control group. CONCLUSION: This study shows that CO is affected by changes in mean airway pressure during HFOV in concordance with the known effects of mean airway pressure during conventional positive pressure ventilation. The mean changes are smaller than expected compared with earlier studies of conventional mechanical ventilation. Further studies are needed to better understand these relationships.

Changes in stroke volume cause change in cardiac output in neonates and infants when mean airway pressure is altered.

BACKGROUND: Based on early studies in the lamb, and in spite of more recent studies in humans, it has been the received opinion that neonates and infants can not change their stroke volume significantly, but are mainly dependent on changes in heart rate, to change cardiac output. To further evaluate the relationship between cardiac output and stroke volume during mechanical ventilation of neonates and infants, we have studied the effects on cardiac output and stroke volume by two different ways of changing mean airway pressure. METHODS: In one group, mean airway pressure was decreased by using a patient triggered mode: pressure support ventilation; in the other, mean airway pressure was increased by increasing positive end-expiratory pressure (PEEP). Changes in cardiac output, heart rate and stroke volume were assessed with the Doppler technique, measuring blood flow velocity in the ascending aorta. RESULTS: Without a significant change in heart rate, we found a significant increase in cardiac output of +16+/-2% (P<0.01) with a decrease in mean airway pressure and a decrease in cardiac output of -13+/-4%, (P<0.02) with an increase in mean airway pressure, depicting a change in stroke volume of +17+/-2% (P<0.02) and -14+/-5%, (P<0.01) respectively. CONCLUSIONS: We conclude that neonates and infants are able to regulate cardiac output by changing the stroke volume to a greater extent than presumed, at least when cardiac output is influenced by changes in the mean airway pressure.

Pressure support ventilation increases cardiac output in neonates and infants.

Fifteen neonates and infants were investigated during pressure controlled ventilation (PCV) and pressure support ventilation (PSV) on a Servo 300 ventilator. Changes in cardiac output (aortic mean blood flow velocity) were assessed with the Doppler technique. During PSV cardiac output increased by 16% (P < 0.01) compared with PCV with equal ventilation. Mean airway pressure decreased significantly during PSV compared with PCV, which may explain the increased cardiac output. During PSV, when inspiratory/expiratory (I:E) relations are dependent on the patient, we found a lower I:E ratio compared with PCV. It can be assumed that at least part of the decreased mean airway pressure is caused by the lower I:E ratio. As the heart rate was unchanged, the variations in cardiac output were caused by alterations in stroke volume. It is concluded that a patient triggered mode should be preferred providing that the neonate/infant has the ability to elicit the ventilator's triggering system.