Persistent pain following common outpatient surgeries in children: A multicenter study in Italy.

INTRODUCTION: The prevalence of persistent postsurgical pain in children is over 20% after major surgeries; however, data are scarce on the prevalence, character, and risk factors among children undergoing common ambulatory surgeries. The primary aim of this study was to evaluate the prevalence of persistent pain following pediatric ambulatory surgery at 1, 3, and 6 months. Secondary aims were to identify risk factors and characterize the pain and consequences of persistent postsurgical pain. METHODS: ASA I-II, ages 1 month to 16 years old, undergoing elective hypospadias repair, herniorraphy, orchiopexy, and orthopedic surgery were enrolled in a prospective, longitudinal, observational study at 3 pediatric centers in Italy. All patients received general plus regional anesthesia. Postoperative pain was evaluated using age appropriate pain scales at 1 and 3 hours. At 1, 3, and 6 months, pain scores were obtained and Parent's Postoperative Pain Measures (<8 yo) and Child Activity Limitations Interview (>8 yo) surveys were administered. RESULTS: About 350 patients completed the study. The prevalence of pain at 1, 3, and 6 months was 24% (84/350), 6.0% (21/350), and 4.0% (14/350), respectively. Inguinal herniorraphy patients experienced significantly higher pain at all 3-time points; 35.6%, 14.9%, and 9.2%. There was no significant association between mean pain scores >4 in PACU and persistent pain. Pain persisting at 6 months had neuropathic characteristics and frequently interfered with daily activities and sleep. CONCLUSION: Our data support the presence of persistent pain in pediatric patients after common surgeries. Most patients who developed persistent pain at 6 months had pain at 1 month. We recommend questioning at follow-up visit about persistent pain and functional impairment with follow-up until resolution.

Prevalence of endotoxemia after surgery and its association with ICU length of stay.

INTRODUCTION: The aim of this observational study was to investigate the prevalence of endotoxemia after surgery and its association with ICU length of stay. METHODS: 102 patients admitted to a university ICU after surgery were recruited. Within four hours of admission, functional data were collected and APACHE II severity score calculated. Arterial blood samples were taken and endotoxemia was measured by chemiluminescence (Endotoxin Activity (EA)). Patients were stratified according to their endotoxin levels (low, intermediate and high) and according to their surgical procedures. Differences between endotoxin levels were assessed by ANOVA, accepting P < 0.05 as significant. Data are expressed as mean +/- SD. RESULTS: EA levels were low in 68 (66%) patients, intermediate in 17 (17%) and high in 17 (17%). Age (61 +/- 17 years) and APACHE II score 8.3 +/- 3.7 (P = 0.542) were not significantly different in the three EA groups. Functional parameters on admission were similar between EA groups: white blood cells 11093 +/- 4605 cells/mm3 (P = 0.385), heart rate 76 +/- 16 bpm (P = 0.898), mean arterial pressure 88.8 +/- 13.6 mmHg (P = 0.576), lactate 1.18 +/- 0.77 mmol/L (P = 0.370), PaO2/FiO2 383 +/- 109 mmHg (P = 0.474). Patients with high levels of EA were characterized by longer length of stay in the ICU: 1.9 +/- 3.0 days in the low EA group, 1.8 +/- 1.4 days in intermediate and 5.2 +/- 7.8 days in high group (P = 0.038). CONCLUSIONS: 17% of our patients were characterized by high levels of endotoxemia as assessed by EA assay, despite their low level of complexity on admission. High levels of endotoxin were associated with a longer ICU length of stay.

Prone position delays the progression of ventilator-induced lung injury in rats: does lung strain distribution play a role?

OBJECTIVE: To investigate if prone position delays the progression of experimental ventilator-induced lung injury, possibly due to a more homogeneous distribution of strain within lung parenchyma. DESIGN: Prospective, randomized, controlled trial. SETTING: Animal laboratory of a university hospital. SUBJECTS: Thirty-five Sprague Dawley male rats (weight 257 +/- 45 g). INTERVENTIONS: Mechanical ventilation in either supine or prone position and computed tomography scan analysis. MEASUREMENTS: : Animals were ventilated in supine (n = 15) or prone (n = 15) position until a similar ventilator-induced lung injury was reached. To do so, experiments were interrupted when respiratory system elastance was 150% of baseline. Ventilator-induced lung injury was assessed as lung wet-to-dry ratio and histology. Time to reach lung injury was considered as a main outcome measure. In five additional animals, computed tomography scans (GE Light Speed QX/I, thickness 1.25 mm, interval 0.6 mm, 100 MA, 100 Kv) were randomly taken at end-expiration and end-inspiration in both positions, and quantitative analysis was performed. Data are shown as mean +/- sd. MEASUREMENTS AND MAIN RESULTS: Similar ventilator-induced lung injury was reached (respiratory system elastance, wet-to-dry ratio, and histology). The time taken to achieve the target ventilator-induced lung injury was longer with prone position (73 +/- 37 mins vs. 112 +/- 42, supine vs. prone, p = .011). Computed tomography scan analysis performed before lung injury revealed that at end-expiration, the lung was wider in prone position (p = .004) and somewhat shorter (p = .09), despite similar lung volumes (p = .455). Lung density along the vertical axis increased significantly only in supine position (p = .002). Lung strain was greater in supine as opposed to prone position (width strain, 7.8 +/- 1.8% vs. 5.6 +/- 0.9, supine vs. prone, p = .029). CONCLUSIONS: Prone position delays the progression of ventilator-induced lung injury. Computed tomography scan analysis suggests that a more homogeneous distribution of strain may be implicated in the protective role of prone position against ventilator-induced lung injury.

Effects of continuous negative extra-abdominal pressure on cardiorespiratory function during abdominal hypertension: an experimental study.

OBJECTIVE: To investigate whether negative extra-abdominal pressure (NEXAP) improves respiratory function and induces a blood shift from the intrathoracic compartment and to assess whether these effects are influenced by abdominal pressure. DESIGN AND SETTING: Prospective, randomized, controlled trial in the animal laboratory of a university hospital. SUBJECTS: Eight sedated and paralyzed pigs (19.6+/-3.4 kg). INTERVENTIONS: Application of NEXAP (-20 cmH(2)O). MEASUREMENTS AND RESULTS: Airway, esophageal, gastric and central venous pressures were recorded simultaneously. Intrathoracic blood volume was assessed by PiCCO. The effects of NEXAP were assessed with and without abdominal hypertension by intraperitoneal insufflation of helium. NEXAP caused a lasting drop of gastric (1.97+/-2.26 mmHg) and esophageal (1.21+/-0.67 mmHg) pressures, while end-expiratory airway pressure was similar, hence transpulmonary pressure increased. Intrathoracic blood volume dropped from 358+/-47 to 314+/-47 ml. The fall was associated with a decrease in central venous pressure (R(2)=0.820). When peritoneal pressure was raised (24.7+/-5.5 mmHg), the effects were less marked. However, the difference between negative pressure around the abdomen and the pressure inside the abdomen (effective NEXAP) was correlated with the proportional changes in intrathoracic blood volume (R(2)=0.648), being greater with more negative effective NEXAP. NEXAP improved chest wall elastance during abdominal hypertension (from 0.067+/-0.023 to 0.056+/-0.021 cmH(2)O/ml). CONCLUSIONS: NEXAP increases lung volume and causes a shift of blood from the intrathoracic compartment. It needs to be tailored against abdominal pressure to be effective.