Nasal mask positive pressure ventilation in paediatric patients with type II respiratory failure

We report our experience with nasal mask ventilation in children and adolescents with type II respiratory failure admitted to the paediatric intensive care unit (PICU) over an 18-month period. Seven patients were treated with nasal mask ventilation during part of their PICU stay. All showed significant improvement in arterial pH, PaCO2, and PaO2/FiO2 from presentation to discharge, although at discharge PaCO2 and PaO2/FiO2 fell outside of the normal range. Complications occurred in four patients. When compared to 11 patients with type II respiratory failure not treated with nasal mask ventilation, the nasal mask ventilation group had a similar PICU length of stay and incidence of complications. We conclude that nasal mask ventilation may be useful in maintaining near normal alveolar ventilation in selected children with type II respiratory failure and that a prospective study of this technique is indicated.

Introducing non-invasive positive pressure ventilation

Non-invasive ventilation techniques provide and enhance alveolar ventilation without the need for an endotracheal airway. These techniques are increasingly being used by nurses to manage patients with type 2 respiratory failure. The author outlines the advantages of, and criteria and contraindications for, using bi-level positive airway pressure (BiPAP).

Extracorporeal life support in pulmonary failure after trauma

OBJECTIVE

To present a series of 30 adult trauma patients who received extracorporeal life support (ECLS) for pulmonary failure and to retrospectively review variables related to their outcome.

METHODS

In a Level I trauma center between 1989 and 1997, ECLS with continuous heparin anticoagulation was instituted in 30 injured patients older than 15 years. Indication was for an estimated mortality risk greater than 80%, defined by a PaO2: FIO2 ratio less than 100 on 100% FIO2, despite pressure-mode inverse ratio ventilation, optimal positive end-expiratory pressure, reasonable diuresis, transfusion, and prone positioning. Retrospective analysis included demographic information (age, gender, Injury Severity Score, injury mechanism), pulmonary physiologic and gas-exchange values (pre-ECLS ventilator days [VENT days], PaO2:FIO2 ratio, mixed venous oxygen saturation [SvO2], and blood gas), pre-ECLS cardiopulmonary resuscitation, complications of ECLS (bleeding, circuit problems, leukopenia, infection, pneumothorax, acute renal failure, and pressors on ECLS), and survival.

RESULTS

The subjects were 26.3+/-2.1 years old (range, 15-59 years), 50% male, and had blunt injury in 83.3%. Pulmonary recovery sufficient to wean the patient from ECLS occurred in 17 patients (56.7%), and 50% survived to discharge. Fewer VENT days and more normal SvO2 were associated with survival. The presence of acute renal failure and the need for venoarterial support (venoarterial bypass) were more common in the patients who died. Bleeding complications (requiring intervention or additional transfusion) occurred in 58.6% of patients and were not associated with mortality. Early use of ECLS (VENT days < or = 5) was associated with an odds ratio of 7.2 for survival. Fewer VENT days was independently associated with survival in a logistic regression model (p = 0.029). Age, Injury Severity Score, and PaO2:FIO2 ratio were not related to outcome.

CONCLUSION

ECLS has been safely used in adult trauma patients with multiple injuries and severe pulmonary failure. In our series, early implementation of ECLS was associated with improved survival. Although this may represent selection bias for less intractable forms of acute respiratory distress syndrome, it is our experience that early institution of ECLS may lead to improved oxygen delivery, diminished ventilator-induced lung injury, and improved survival.

Major burns in Cape Town: a modified burns score for patient triage

Major burns equal to, or greater than, 30 per cent total body surface area (TBSA) constitute 23 per cent of the admissions to the adult burns unit in Cape Town. A retrospective review over a 28-month period identified 87 cases of major burns. This paper summarizes the epidemiology and mortality amongst this patient group over this period. Demand for treatment can exceed bed availability in the unit. The difficult issue, this raises, of patient triage in relation to the relatively limited resources is addressed and a simple modified burns score proposed for this unit. The effect this score would have in optimizing the use of our resources is demonstrated.

Acute hypoxemic respiratory failure in children: case mix and the utility of respiratory severity indices

OBJECTIVE

Acute hypoxemic respiratory failure (AHRF) is a common reason for emergency pediatric intensive care. An objective assessment of disease severity from acute physiological parameters would be of value in clinical practice and in the design of clinical trials. We hypothesised that there was a difference in the best early respiratory indices in those who died compared with those who survived.

DESIGN

A prospective observational study of 118 consecutive AHRF admissions with data analysis incorporating all blood gases.

SETTING

A pediatric intensive care unit in a national children's hospital.

INTERVENTIONS

None.

RESULTS

Mortality was 26/118, 22% (95 % confidence interval 18-26%). There were no significant differences in the best alveolar-arterial oxygen tension gradient (A-aDO2, torr), oxygenation index (OI), ventilation index (VI), or PaO2/FIO2 during the first 2 days of intensive care between the survivors and non-survivors. Only the mean airway pressure (MAP, cm H2O) used for supportive care was significantly different on days 0 and 1 (p < 0.05) with higher pressure being used in non-survivors. Multiple logistic regression analysis did not identify any gas exchange or ventilator parameter independently associated with mortality. Rather, all deaths were associated with coincident pathology or multi-organ system failure, or perceived treatment futility due to pre-existing diagnoses instead of unsupportable respiratory failure. When using previously published predictors of outcome (VI > 40 and OI > 40; A-aDO2 > 450 for 24 h; A-aDO2 > 470 or MAP > 23; or A-aDO2 > 420) the risk of mortality was overestimated significantly in the current population.

CONCLUSION

The original hypothesis was refuted. It appears that the outcome of AHRF in present day pediatric critical care is principally related to the severity of associated pathology and now no longer solely to the severity of respiratory failure. Further studies in larger series are needed to confirm these findings.

[An index assessment of the degree of the respiratory failure in funnel chest]

An evaluation was done of respiratory failure in 149 children aged 3 to 15 presenting with funnel-shaped chest deformity (FCD). An original classification is suggested of degree of respiratory failure in FCD in children. Based on the index assessment of clinical and functional parameters an outline has been worked out for degree of respiratory failure. The criteria obtained are statistically significant; being able of giving quantitative assessment of degree of respiratory failure they can serve as control figures to be used in evaluations designed to study time course of changes in respiratory failure.

Nonrespiratory predictor of mechanical ventilation dependency in intensive care unit patients

OBJECTIVE

To determine the role of serum albumin concentration as a predictor of mechanical ventilation dependency.

DESIGN

Prospective, observation trial.

SETTING

Multidisciplinary intensive care unit (ICU) in a university hospital.

PATIENTS

One hundred forty-five consecutive patients who required mechanical ventilation for > 72 hrs.

INTERVENTIONS

Patients were classified into five different groups based on the cause of respiratory failure. The following parameters were recorded daily: serum albumin concentration; Acute Physiology and Chronic Health Evaluation II (APACHE II) score; and fluid balance. Using multiple regression, multiple logistic regression analysis, and the Anderson-Gill proportional hazards model, we determined the metabolic factors that could help predict weaning success.

MEASUREMENTS AND MAIN RESULTS

The mean length of ICU stay was 12.3 +/- 1.0 days. The duration of mechanical ventilation dependency was 10.5 +/- 1.0 days. The initial mean serum albumin concentration was 25.2 +/- 0.6 g/L. The APACHE II score on the first day of ICU stay was 19.1 +/- 0.6. Although albumin concentration was significantly lower and the APACHE II score was significantly higher in ICU nonsurvivors than in ICU survivors, albumin concentration on ICU admission was not a predictor of the length of time spent receiving mechanical ventilation. The profile of albumin concentration changes was different between weaned and mechanical ventilation-dependent patients. At the time of weaning patients from the ventilator, the median albumin concentration was higher than in those patients who continued to be supported by mechanical ventilation. This effect of albumin could not be attributed to patient fluid balance or to the severity of illness since each factor had an independent influence in predicting weaning, using the Anderson-Gill proportional hazards models.

CONCLUSIONS

Initial serum albumin concentration did not necessarily predict weaning success. However, when serum albumin concentration was assessed on a daily basis, its trend was important in determining the relative chance of being successfully weaned from the ventilator. This finding suggests that albumin may be an index of the metabolic status of the patient, which could be important in determining the weanability of the patients who are mechanically ventilated for prolonged periods of time.

[Are ISS and PTS unsuitable trauma scores for prediction of (possible) post-traumatic lung failure?]

Prostanoids are inflammatory mediators which originate from endothelial cells following local tissue damage. That is why plasma levels of prostanoids are possible markers of inflammatory response and severity of trauma. We were able to demonstrate that the systemic release of prostanoids does not depend on the score values (ISS, PTS) but rather on different trauma patterns (chest trauma, head injury). Influencing vascular permeability and resistance elevated plasma levels of prostanoids may explain the impairment of pulmonary function in traumatized patients. It seems to be useful to re-evaluate the scoring systems with respect to chest trauma and head injury.

[Clinical significance of detection of plasma fibronectin in respiratory failure]

Plasma fibronectin (PFn) level was measured with immumoelectrophoresis in 40 healthy adults and 174 patients (221 person-times) with respiratory insufficiency (R I). The levels of PFn in 40 healthy adults, 85 person-times of R I, 27 person-times of Type I respiratory failure (RF I), 82 person-times of RF II, and 27 person-times of iatrogenic RF (IRF) were 292.48 +/- 43.11 mg/L, 253.12 +/- 67.00 mg/L 141.97 +/- 70.84 mg/L, 180.48 +/- 49.96 mg/L and 263.49 +/- 70.05 mg/L respectively. The levels of PFn of patients with R I, RF I and RF II were significantly lower than that in healthy adults (P < 0.001). The level of PFn of patients with TRF was significantly lower than that in healthy adults (P < 0.05). There was positive correlation between the levels of PFn and PaO2 in 221 person-times of R I (r = 0.5358, P < 0.001), RF I r = 0.3822, P < 0.05). RF II (r = 0.3050, P < 0.01), and IRF (r = 0.4963, P < 0.02). There was negative correlation between the levels of PFn and PaCO2 in 221 person-times of R I (r = -0.2053, P < 0.005) and RF II (r = -0.2181, P < 0.05). In 34 patients with RF, the PFn before treatment was significantly lower than that two weeks after treatment (147.80 +/0 61.59 mg/L vs 214.56 +/- 56.12 mg/L) (P < 0.001). Among 33 cases of RF whose level of PFn was < 150 mg/L, 18 cases complicated multiple system organ failure and 4 cases complicated adult respiratory distress syndrome. The average level of PFn in 3 death cases was lower than 100 mg/L. It is suggested that PFn level might be used as an index in making early diagnosis, monitoring RF and predicating progosis of RF.

[A pathogenetic classification of closed thoracic trauma]

Based on experimental and clinical data the authors propose a classification of closed thoracic traumas which allow to form relatively similar groups among patients with closed thoracic traumas having orientation of the leading pathogenetic factor. The proposed classification allows to form rational curative programs as early as at the prehospital and early hospital stages.

Outcome from respiratory failure

A physician's assessment of the probable outcome of an episode of respiratory failure should be based on a combination of survival data from large studies and specific knowledge about the individual case in question. Clearly, mortality rates in cases of ARF are influenced by a number of factors. In general, only a minority of patients with ARF complicating COPD require mechanical ventilation. In these cases, mortality often is related to the nature of the precipitating illness and the severity of the patient's underlying chronic respiratory disease. The long-term prognosis in patients with COPD who survive an episode of ARF is related primarily to the severity of the patient's underlying disease. Acute mortality is higher in patients with ARDS than in patients with ARF complicating COPD. Although a significant number of ARDS patients die of their underlying illness, mortality in others more commonly appears to be related to sepsis and multiple organ failure rather than end-stage respiratory disease. Pulmonary function in survivors of ARDS is quite variable, and may be related to the severity of the acute episode. ARF has a particularly poor prognosis when associated with certain underlying illnesses such as hematologic malignancy.

Severe respiratory depression after epidural morphine in a patient with myotonic dystrophy

We describe a patient with myotonic dystrophy who underwent cholecystectomy, and developed severe respiratory depression following epidural administration of morphine to provide postoperative analgesia. At preoperative assessment, he demonstrated near normal vital capacity and maximal voluntary ventilation, but the presence of chronic ventilatory failure with a resting value of PaCO2 51 mmHg. Anaesthesia was produced by a combination of epidural and light general anaesthesia without intravenous anaesthetics, narcotics or neuromuscular relaxants. Five hours after epidural administration of 2 mg morphine, the patient developed severe respiratory depression with a PaCO2 of 93 mmHg. Intravenous naloxone resulted in transient improvement in minute volume, suggesting that epidural morphine was responsible for the depression. Epidural morphine can cause unexpected respiratory depression, even at a small dose, because of the sensitivity of the respiratory centre to morphine in patients with myotonic dystrophy.

Prospective evaluation of clinical scoring systems in infants and children with cardiopulmonary insufficiency after cardiac surgery

OBJECTIVE

To document severity of illness and to evaluate the predictive value of clinical scoring systems in infants and children with cardiopulmonary insufficiency after cardiac surgery.

DESIGN

Prospective study with follow up to hospital discharge.

SETTING

A multidisciplinary pediatric ICU in a University Hospital.

PATIENTS

Between 1/1989 and 4/1992 441 infants and children with congenital heart disease underwent open heart surgery. 128 of these patients developed postoperative cardiopulmonary insufficiency and were entered into this study.

METHODS

Data relevant to the Acute Physiologic Score for Children (APSC), Pediatric Risk of Mortality (PRISM), Therapeutic Intervention Scoring System (TISS) and Organ System Failure (OSF) score were collected in all patients during the first 4 days of postoperative intensive care.

RESULTS

The mean age of the patients was 1.5 +/- 0.2 years. The mean duration of mechanical ventilation and ICU care was 6.2 +/- 0.6 and 8.1 +/- 0.7 days, respectively. On the first postoperative day the mean APSC and PRISM scores of survivors and nonsurvivors were 13.9 +/- 1.3 vs 24.5 +/- 1.3 (p < 0.001) and 6.1 +/- 0.5 vs 19.6 +/- 1.9 (p < 0.001), respectively. The mean TISS and OSF scores of survivors and nonsurvivors were 46 +/- 0.8 vs 57.8 +/- 1.4 (p < 0.001), and 2.2 +/- 0.2 vs 3.4 +/- 0.2 (p < 0.001), respectively. The overall hospital mortality rate was 9.9%, the hospital mortality rate of patients with postoperative cardiopulmonary insufficiency 34%. Patients with an APSC score < 10 and a PRISM score < 5 had a survival rate of 100%, whereas patients with an APSC score > 30 and a PRISM score > 25 had a mortality rate of 100%. The area under the receiver operating characteristic (ROC) curve for APSC, PRISM and TISS was 0.847, 0.826 and 0.793, respectively.

CONCLUSION

APSC, PRISM and TISS describe accurately severity of illness in infants and children with cardiopulmonary insufficiency after cardiac surgery and all scores identify those patients at increased risk for mortality.

Management of respiratory failure

Hypoxaemia and hypercapnia are common clinical problems. A clear understanding of the diseases and pathophysiological processes that cause respiratory failure is important in making decisions about the concentration of oxygen to give, the type of face-mask to use, and the place of artificial ventilation.

[Radiological aspects of acute respiratory insufficiency after heart valve prosthesis]

Analysis of the x-ray findings in 156 patients with acute respiratory insufficiency (ART) in the immediate periods after implantation of heart valve prostheses has shown that various pulmonary complications, such as pulmonary edema (in 84% of cases), atelectasis, hypoventilation (5.1%), hemothorax (6.4%), pneumothorax (0.6%) were the prerequisites for the development of respiratory disorders. Pneumonias were not the primary cause of ART but an additional factor for the respiratory disorder progress, for they develop in the presence of previous pulmonary changes. The necessity and possibility of establishing the pathogenetic mechanism of pulmonary edema (cardiogenic or noncardiogenic one) is shown. The authors emphasize the desirability of regular x-ray examinations as a supplementary method in monitoring the patients with acute respiratory insufficiency.

Predicting survival in AIDS patients with respiratory failure. Application of the APACHE II scoring system

This article describes the APACHE II classification system as a measure of severity of illness applied to AIDS patients with respiratory insufficiency. Among 82 patients, observed mortality in patients with high APACHE II scores (greater than 30) and those with low scores (less than 18) was significantly higher than predicted. There was variable correlation between predicted and observed mortality in the other APACHE II score ranges. The usefulness of the APACHE II scoring system is reviewed as limited and inaccurate in predicting survival rates in AIDS patients with respiratory failure.

Early prognostic indices after cardiopulmonary resuscitation (CPR). The Cerebral Resuscitation Study Group

An early prediction score (EPS) is constructed as the sum of five events: the type of cardiac arrest is ventricular fibrillation; the type of respiratory arrest is gasping; pupil reaction is unequal, slow or normal, but present; swallowing activity is present and the cardiac arrest has been witnessed. Presence of any of these events contributes one point to the score, while absence contributes nothing to it. EPS during resuscitation results in a comparable amount of information, whether used to predict success, alive and conscious 14 days post-CPR or no-success. EPS early (10 min) after initially successful resuscitation is more effective in predicting no-success than success. EPS during CPR does not allow decision making as far as stopping or continuing CPR efforts. EPS early after CPR does neither allow decision making as far as stopping or continuing critical care efforts after initially successful CPR. EPS does, however, weigh the likelihood of success against that of no-success, which can be used when discussing the chances of the patient with his relatives.