A traffic-light coding system to organize emergency surgery across surgical disciplines.

BACKGROUND: Emergency surgery is associated with night-time procedures and disruption of elective surgery. An analysis was undertaken of the effect of classifying emergency operations uniformly with a three-tier urgency colour code and the use of dedicated daytime operating rooms. METHODS: Observed changes from 2001 to 2012 in the number, timing and ability to meet the urgency-designated colour code deadline were retrieved from the computer-based operating theatre organization system for all emergency operations. RESULTS: The number of emergency operations performed annually ranged from 3330 to 4341, with an increasing trend. The proportion of night-time emergency operations decreased from 27.4 per cent (2563 of 9347) before to 23.5 per cent (7731 of 32,959) after introduction of the colour coding system in 2004 (χ2 = 61.94, 1 d.f., P < 0.001). In 2007, owing to long preoperative delays in patients with acute appendicitis and acute cholecystitis, colour codes for these patients were upgraded from 'orange' to 'red' and from 'yellow' to 'orange' respectively. The proportion of patients operated on with a red code before and after this change increased from 45.2 per cent (5831 of 12,907 operations) to 62.7 per cent (13,020 of 20,778 operations; χ2 = 986.99, 1 d.f., P < 0.001). In 2012, the office-hours raw utilization time for the principal emergency operation theatre was 85.4 per cent. CONCLUSION: The structural separation of elective and emergency surgery, the use of dedicated daytime operating theatres and the implementation of a universal classification of emergency operations reduced night-time surgery, improved the efficiency of operating theatre utilization during daytime, shortened preoperative delay in patients requiring urgent surgery, and enabled monitoring and corrective actions for providing emergency surgery services.

Intramucosal pH and endotoxin and cytokine release in severe acute pancreatitis.

It has been postulated that in severely ill patients splanchnic hypoperfusion may cause endotoxin release from the gut, and this leakage of endotoxin into the circulation can trigger the cascade of inflammatory cytokines. We tested this hypothesis in 9 patients with acute severe pancreatitis by monitoring gastric intramucosal pH (pHi) as measure of splanchnic hypoperfusion at 12-h intervals trying to correlate it to endotoxin and cytokine release. Only 3 of 59 samples, obtained from 3 patients contained circulating endotoxin. Thirteen of 15 plasma samples drawn at pHi <7.20 did not contain endotoxin. The pHi was significantly lower in patients who subsequently developed 3 or more organ failures (P = 0.0017, analysis of variance). Although endotoxemia was only occasionally found, most patients had measurable interleukin 1beta (IL-1beta), interleukin 6 (IL-6), interleukin 8 (IL-8), and interleukin 10 (IL-10) in their plasma. Concentrations of IL-6, IL-8, and IL-10 on admission correlated to degree of organ dysfunction as measured by the multiple organ system failure score (P = 0.035, r = 0.74; P = 0.010, r = 0.91; P = 0.021, r = 0.82, respectively). In conclusion, patients with acute, severe pancreatitis often have splanchnic hypoperfusion and produce a wide array of cytokines despite a rare occurrence of endotoxemia.

A comparison of continuous positive pressure ventilation, combined high frequency ventilation and airway pressure release ventilation on experimental lung injury.

In pigs with oleic induced lung injury, the effectiveness of combined high frequency ventilation (CHFV, with VDR-Phasitron) and airway pressure release ventilation (APRV) were compared to continuous positive pressure ventilation (CPPV) in a randomized study. The respiratory rate was 15/min, CPAP 8 mmHg and FiO2 0.25. PaCO2 was maintained at 5 kPa. PaO2 was significantly lower with APRV (12.5 +/- 3.9 kPa, CPPV: 15.8 +/- 3.9 kPa, and CHFV: 15.5 +/- 3.2 kPa). This was in accordance with the lowest peak airway pressure during APRV (20.9 +/- 4.8 mmHg, CPPV: 26.3 +/- 4.4 mmHg and CHFV: 28.2 +/- 3.7 mmHg). There was no difference in the pericardiac pressure between the 3 ventilation modes. The pressure related depressive effects on the cardiovascular function during CHFV and APRV were similar to those during CPPV. Adequate oxygenation and ventilation could be achieved with both CHFV and APRV, but these methods were not superior to CPPV.

Validation of air tonometric measurement of gastric regional concentrations of CO2 in critically ill septic patients.

OBJECTIVE: To evaluate the accuracy of continuous air tonometry (Tonocap, Tonometric Division, Instrumentarium, Helsinki, Finland). DESIGN: The accuracy of air tonometry was tested by comparing it with conventional saline tonometry in mechanically ventilated, critically ill septic patients and in vitro determining the partial pressure of carbon dioxide (PCO2) of humidified gases with known concentrations of CO2. SETTING: A mixed intensive care unit in a university hospital. PATIENTS: 16 mechanically ventilated patients with sepsis. MEASUREMENTS AND RESULTS: Two gastric tonometer catheters (TRIP NGS catheter, Tonometric Division, Instrumentarium, Helsinki, Finland) were introduced into the patients' stomachs. The control catheter was used as a conventional saline tonometer and the other catheter was used with the Tonocap monitoring device. A total of 153 paired measurements was made and analysed according to Bland and Altman. The mean difference between air PCO2 and saline PCO2 values (bias), the standard deviation of the differences (precision), and the Pearson correlation coefficient between air PCO2 and saline PCO2 were calculated. The data on patients were pooled and calculated for different cycle times. The mean bias (kPa) was-0.02 with a 10-min cycle time, 0.31 with 15 min, 0.56 with 30 min and 0.21 with 60-min. The precisions were 0.39, 0.54, 0.44 and 0.76, respectively. Pearson correlation coefficients were 0.93, 0.97, 0.95 and 0.82, respectively (p < 0.0001). In vitro tonometry with the Tonocap was performed in a gas chamber fully saturated with known CO2 concentrations. The clinically important 10-min cycle time was tested with 5 Tonocap monitors. Except for the first 10-min cycle time, PCO2 values determined by the Tonocap monitoring systems were comparable to known CO2 concentrations. CONCLUSIONS: The accuracy of Tonocap continuous air tonometry is close to that of conventional saline tonometry. Moreover, the clinically important 10-min cycle time with air tonometry correlated very well with saline tonometry and the time response with air tonometry was short.

Interleukin 1 receptor antagonist and E-selectin concentrations: a comparison in patients with severe acute pancreatitis and severe sepsis.

PURPOSE: This prospective clinical study was designed to compare interleukin 1 receptor antagonist (IL-1ra) and E-selectin concentrations in patients with severe acute pancreatitis to those with severe sepsis. MATERIALS AND METHODS: Nine consecutive patients with severe acute pancreatitis and 11 consecutive patients with severe sepsis admitted to a medical/surgical intensive care unit were included in the study. Plasma concentrations of IL-1ra and E-selectin were serially measured daily for 7 days or throughout their stay in the intensive care unit if shorter. RESULTS: The concentrations of IL-1ra were significantly higher on admission in patients with severe sepsis compared with the patients with severe pancreatitis (median levels 10,500 and 2,600 pg/mL, respectively, P = .007). When the data from the first 3 days were analyzed using analysis of variance (ANOVA), the levels of IL-1ra and E-selectin were similar in both groups. The concentrations of IL-1ra and E-selectin correlated to the development of multiorgan dysfunction as assessed by sequential organ failure assessment (SOFA) score (P = .032 and .043, respectively). CONCLUSION: This study shows that IL-1ra and E-selectin are released in acute severe pancreatitis, and the levels seem to be comparable to those in patients with severe sepsis. Concentrations of IL-1ra and E-selectin correlate to the development of multiorgan failure as indicated by high SOFA scores during the first week of disease.

Diaphragmatic movement using ultrasound during spontaneous and mechanical ventilation: effect of tidal volume.

Using ultrasound (US) the effect of various tidal volumes on the movement of ventral, dome and dorsal parts of the right hemidiaphragm was studied, both during spontaneous and mechanical ventilation. Six healthy non-medicated volunteers who were in the supine position breathed spontaneously shallowly (tidal volume (VT) being 400 ml) (SB), and deeply (VT 1000 ml) (SB-deep). In addition, they were mechanically ventilated with intermittent positive pressure ventilation at three different VT's: 500 ml (IPPV-500), 1000 ml (IPPV-1000) and 1700 ml (IPPV-1700). The maximal movement was recorded in the ventral part in 2 volunteers during SB, in 3 during SB-deep, and in 3 and 5 subjects during IPPV-500 and IPPV-1700, respectively. The movement in dome was 100% during SB (all others standardized to this), 303 +/- 107% during SB-deep, 82 +/- 30% during IPPV-500, 165 +/- 70% during IPPV-1000 and 266 +/- 153% during IPPV-1700. An increased tidal volume is associated with an increase in the diaphragmatic movement studied by US. However, a larger VT is needed during mechanical ventilation to achieve the same amount of change as occurred with deep spontaneous breathing.

Endotracheal tube versus face mask with and without continuous positive airway pressure (CPAP).

Various ways of delivering continuous positive airway pressure (CPAP) have been extensively studied, with little attention, however, being paid to the effects of an intubation tube compared with breathing through a face mask, with or without CPAP. Pulmonary and cardiovascular variables were measured while 12 patients recovering from coronary artery bypass grafting were spontaneously breathing at ambient airway pressure, then at 7.4 mmHg (1 kPa) CPAP, and again at ambient pressure just before extubation. The same stages were repeated immediately after extubation, with patients breathing through a tight-fitting face mask. Arterial oxygen tension (Pao2, mean +/- s.d.) was better when the patients were breathing at ambient pressure through a face mask (11.7 +/- 2.8 kPa) than when they were intubated (10.6 +/- 2.4 kPa, P < 0.05). Compared with ambient pressure, CPAP (7.4 mmHg) (1 kPa) increased Pao2 in both modes (13.4 +/- 3.5 kPa with mask, and 12.6 +/- 3.5 kPa when intubated, n.s.). The best arterial oxygen saturation was measured during CPAP with a face mask (96 +/- 1%). Cardiac output remained unchanged in all the breathing modes. After coronary artery bypass grafting, spontaneous breathing with a face mask resulted in better Pao2 than breathing through an endotracheal tube, both with and without 7.4 mmHg (1 kPa) CPAP. This study indicates that unnecessary delay in extubation should be avoided.

The effect of combined high frequency ventilation with and without continuous positive airway pressure in experimental lung injury.

Combined high frequency ventilation (CHFV) with 8 mmHg (1.0 kPa) continuous positive airway pressure (CPAP) and without CPAP (CHFV0) were compared to each other, and to continuous positive pressure ventilation (CPPV) with 8 mmHg (1.0 kPa) CPAP in pigs with oleic acid induced lung injury. The respiratory rate was 15 min-1 and the high frequency (HF) rate 360 min-1. Arterial carbon dioxide tension (PaCO2) was adjusted to 5 kPa and 25% oxygen was used. After CHFV, CPAP was briefly discontinued to allow the establishment of CHFV0 in order to examine the cardiovascular and pulmonary effects of combined high frequency ventilation alone. Mean arterial oxygen tension (PaO2) was 15.8 +/- 3.9 kPa during CPPV, 15.5 + 3.2 kPa during CHFV and 13.2 +/- 5.1 kPa during CHFV0 (ns). The peak airway pressure and the pericardiac pressure were lowest during CHFV0. CHFV provoked significant cardiovascular depression (mean arterial pressure, stroke index, left and right ventricle stroke work index). When compared to CPPV, a non-significant trend towards improved cardiovascular function was found during CHFV0. With similar mean airway pressures (during CHFV0) or the same CPAP (during CHFV) as during CPPV, no further improvement in oxygenation due to HF waves was found. Airway pressure was the major factor causing alterations in cardiovascular function, not the ventilation technique.

The effect of a heat and moisture exchange filter on sidestream spirometry in critically ill patients.

Sidestream spirometry has enabled continuous on-line monitoring of the pulmonary mechanics in intubated patients. We studied the effect of the heat and moisture exchange filter (HMEF) on the displayed spirometry values of a commercial multiparameter pulmonary monitor in 35 stable ICU patients needing mechanical ventilatory support. There were statistically significant differences in tidal volumes, airway pressures, compliances and end-tidal CO2-values between the two sites of measurements on both sides on the HMEF. The effect of the HMEF was linear in almost every patient. However, the change of the displayed values was clinically of minor importance. In conclusion, we suggest that the HMEF can be safely used between the patient and the monitoring site in routine ventilatory monitoring of ICU patients.

Airway pressure release ventilation by mask.

A 53-yr-old woman with mediastinitis after thymectomy for myasthenia gravis was successfully mechanically ventilated with airway pressure release ventilation (APRV), which was started when the patient was intubated and continued by mask for 2 days after extubation. Mask APRV allowed efficient mechanical ventilation.

Combined effects of prone positioning and airway pressure release ventilation on gas exchange in patients with acute lung injury.

BACKGROUND: Prone positioning has been shown to improve oxygenation in 60-70% of patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Another way to improve matching of ventilation to perfusion is the use of partial ventilatory support. Preserving spontaneous breathing during mechanical ventilation has been shown to improve oxygenation in comparison with controlled mechanical ventilation. However, no randomized studies are available exploring the effects of preserved spontaneous breathing on gas exchange in combination with prone positioning. Our aim was to determine whether the response of oxygenation to the prone position differs between pressure-controlled synchronized intermittent mandatory ventilation with pressure support (SIMV-PC/PS) and airway pressure release ventilation with unsupported spontaneous breathing (APRV). METHODS: We undertook a prospective randomized intervention study in a medical-surgical adult intensive care unit of a university hospital. Of 45, 33 ALI patients (acute lung injury) within 72 h after initiation of mechanical ventilation, and in whom the prone position was applied according to a predefined strategy, were included in the study. After initial stabilization the patients were randomized to receive either SIMV-PC/PS or APRV with predefined general ventilatory goals (PEEP, tidal volume, inspiratory pressure and PaCO2-level). The protocol for prone positioning was the same for both treatment arms. Prone positioning was triggered by finding a PaO2/FiO2-ratio below 200 mmHg evaluated twice per day. The duration of each prone episode was 6 h. RESULTS: The first two episodes of prone positioning were analyzed. Gas exchange was measured before and at the end of prone positioning. Of the 45 patients enrolled, 33 were turned prone once and 28 twice. No significant differences were detected in baseline characteristics. Changes in oxygenation were analyzed in response to the first and second prone episodes 5 h and 24 h after randomization and initiation of SIMV-PC/PS or APRV respectively. Before the first prone episode the PaO2/FiO2-ratio was significantly better (P = 0.02) in the APRV-group (median; interquartile range) (162; 108-192 mmHg) than in the SIMV-PC/PS-group (123; 78-154 mmHg). The response in oxygenation to the first prone episode was similar in both groups: PaO2/FiO2-ratio increased 39.5; 17.75-77.5 mmHg in the SIMV-PC/PS-group and 75.0; 9.0-125.0 mmHg in the APRV-group (P = 0.49). Before the second prone episode, the PaO2/FiO2-ratio was comparable (SIMV-PC/PS 130.5; 61.0-161.0 mmHg vs. APRV 134; 98.3-175.0 mmHg). Improvement in oxygenation was significantly (P = 0.02) greater in the APRV group (82; 37.0-141.0 mmHg) than in the SIMV-PC/PS group (50; 24.0-68.8 mmHg) during the second prone episode. General ventilatory and hemodynamic variables and use of sedatives were similar in both groups during the study. CONCLUSIONS: APRV during prone positioning is feasible in the treatment of ALI patients. APRV after 24 h appears to enhance improvement in oxygenation in response to prone positioning.

Continuous positive airway pressure by mask in patients after coronary surgery.

Thirty patients who underwent coronary artery bypass grafting were randomized to receive 30% oxygen by mask either with an ambient airway pressure or with 7.4 mmHg (1 kPa) continuous positive airway pressure (CPAP) for 8 h after extubation. Arterial blood oxygen tension (PaO2) decreased remarkably in the control group after extubation (from 19.2 +/- 5.3 kPa to 12.4 +/- 2.7 kPa) but less in the CPAP group (from 16.4 +/- 3.3 kPa to 14.0 +/- 2.1 kPa). On the second postoperative morning PaO2 was equally low in both groups (control: 8.4 +/- 1.5 kPa, CPAP: 8.9 +/- 1.9 kPa). Atelectatic areas were seen with similar frequency in both groups, 17% (whole material) on the first and 50% on the second postoperative morning. Atelectasis was more common in patients with internal thoracic artery grafting and/or pleural drainage. In conclusion, CPAP therapy was well tolerated, and minimized the decrease in PaO2 after extubation, but could not prevent the poor oxygenation or the late development of atelectatic areas on the second postoperative day.

Diaphragmatic movement studied with ultrasound during spontaneous breathing and mechanical ventilation with intermittent positive pressure ventilation (IPPV) and airway pressure release ventilation (APRV) in man.

Earlier knowledge about diaphragmatic movement during mechanical ventilation is based on radiological information. Since real-time bed-side monitoring is now possible the movement of the right hemidiaphragm was studied using ultrasound (US), both during spontaneous and mechanical ventilation. Nine healthy non-medicated volunteers lying supine were exposed to the following ventilation modes in random order: 1. breathing air at ambient pressure, or 2. at 7.6 mmHg of CPAP or 3. mechanical ventilation with airway pressure release ventilation (APRV), or 4. with IPPV, by mask. The movement of the diaphragm was recorded with a US sector transducer, imaging the ventral, dome and dorsal parts. The maximal movement was detected in the dome in four volunteers during spontaneous breathing with both ambient pressure and CPAP, but in the ventral part in seven and six volunteers, respectively, during APRV and IPPV. Diaphragmatic movement can be studied with US and the findings support the earlier study, with the diaphragm shifting towards the non-dependent regions of the lungs during mechanical ventilation. In this respect APRV is similar to IPPV.

Systemic inflammatory response syndrome without systemic inflammation in acutely ill patients admitted to hospital in a medical emergency.

Criteria of the systemic inflammatory response syndrome (SIRS) are known to include patients without systemic inflammation. Our aim was to explore additional markers of inflammation that would distinguish SIRS patients with systemic inflammation from patients without inflammation. The study included 100 acutely ill patients with SIRS. Peripheral blood neutrophil and monocyte CD11b expression, serum interleukin-6, interleukin-1beta, tumour necrosis factor-alpha and C-reactive protein were determined, and severity of inflammation was evaluated by systemic inflammation composite score based on CD11b expression, C-reactive protein and cytokine levels. Levels of CD11b expression, C-reactive protein and interleukin-6 were higher in sepsis patients than in SIRS patients who met two criteria (SIRS2 group) or three criteria of SIRS (SIRS3 group). The systemic inflammation composite score of SIRS2 patients (median 1.5; range 0-8, n=56) was lower than that of SIRS3 patients (3.5; range 0-9, n=14, P=0.013) and that of sepsis patients (5.0; range 3-10, n=19, P<0.001). The systemic inflammation composite score was 0 in 13/94 patients. In 81 patients in whom systemic inflammation composite scores exceeded 1, interleukin-6 was increased in 64 (79.0%), C-reactive protein in 59 (72.8%) and CD11b in 50 (61.7%). None of these markers, when used alone, identified all patients but at least one marker was positive in each patient. Quantifying phagocyte CD11b expression and serum interleukin-6 and C-reactive protein concurrently provides a means to discriminate SIRS patients with systemic inflammation from patients without systemic inflammation.

Time course of beta 2-integrin CD11b/CD18 (Mac-1, alpha M beta 2) upregulation on neutrophils and monocytes after coronary artery bypass grafting. CD11b upregulation after CABG surgery.

Although upregulation of CD11b/CD18 receptor, i.e. activation of neutrophils and monocytes, during cardiopulmonary bypass is well documented, the duration of the active state after uncomplicated operation is less understood. We therefore investigated CD11b expression of phagocytes in blood samples collected 2-4, 24, 48 and 72 h after coronary artery bypass grafting. CD11b expression on neutrophils was significantly elevated at 2-4 and 24 hours after operation as compared with baseline. On monocytes, expression peaked at 24 h and returned to baseline by 72 h. Because CD11b is a sensitive marker, effects of different sampling techniques on its expression were also studied. CD11b expression was similar in samples collected with a syringe from arterial or central venous catheter or with open technique from cubital vein. On neutrophils from healthy subjects, sampling with syringe caused small (10%) but statistically significant increase of expression. We conclude that activated neutrophils disappear from circulation within hours after CABG surgery while activated monocytes may continue circulating for 2-3 days, and that CD11b sampling can be done with a syringe.

Airway pressure release ventilation during acute lung injury: a prospective multicenter trial.

OBJECTIVE: To evaluate the feasibility of airway pressure release ventilation (APRV) in providing ventilatory support to patients with acute lung injury of diverse etiology and mild-to-moderate severity. DESIGN: Prospective, multicenter, nonrandomized crossover trial. SETTING: ICUs in six major referral hospitals. PATIENTS: Fifty adult patients with respiratory failure requiring mechanical ventilation and positive end-expiratory airway pressure. INTERVENTIONS: After optimization of continuous positive airway pressure (CPAP), conventional ventilation and APRV were administered sequentially for 30 mins. During APRV, the CPAP level and airway pressure release level were adjusted to prevent hypoxemia, while the degree of ventilatory support was adjusted by altering the frequency of pressure release. MEASUREMENTS AND MAIN RESULTS: Circulatory and ventilatory pressures, arterial blood gases and pH, heart rate, and respiratory rate were measured. Alveolar ventilation was augmented adequately in 47 of 50 patients by APRV. Adjustment of APRV required an increase in mean CPAP from 13 +/- 3 (SD) to 21 +/- 9 cm H2O and a release pressure of 6 +/- 5 cm H2O. This airway pressure pattern produced a mean airway pressure comparable to that pressure achieved during conventional ventilation. Failure of APRV in three patients could be attributed to an inadequate level of CPAP or an inadequate APRV rate. While maintaining oxygenation of arterial blood and circulatory function, APRV allowed a substantial (55 +/- 17%; p less than .0001) reduction in peak airway pressure compared with conventional positive pressure ventilation adjusted to deliver a comparable or lower level of ventilatory support. CONCLUSIONS: APRV is a feasible alternative to conventional mechanical ventilation for augmentation of alveolar ventilation in patients with acute lung injury of mild-to-moderate severity.

Markers of systemic inflammation predicting organ failure in community-acquired septic shock.

To obtain predictors of organ failure (OF), we studied markers of systemic inflammation [circulating levels of interleukin-6 (IL-6), IL-8, soluble IL-2 receptor (sIL-2R), soluble E-selectin and C-reactive protein, and neutrophil and monocyte CD11b expression] and routine blood cell counts in 20 patients with systemic inflammatory response syndrome and positive blood culture. Eight patients with shock due to community-acquired infection developed OF, whereas 11 normotensive patients and one patient with shock did not (NOF group). The first blood sample was collected within 48 h after taking the blood culture (T1). OF patients, as compared with NOF patients, had at T1 a lower monocyte count, a lower platelet count, higher levels of CD11b expression on both neutrophils and monocytes, and higher concentrations of IL-6, IL-8 and sIL-2R. C-reactive protein and soluble E-selectin concentrations did not differ between groups. No parameter alone identified all patients that subsequently developed OF. However, a sepsis-related inflammation severity score (SISS), developed on the basis of the presence or absence of shock and on the levels of markers at T1, identified each patient that developed OF. The maximum SISS value was 7. The range of SISS values in OF patients was 2-5, and that in NOF patients was 0-1. In conclusion, high levels of CD11b expression, depressed platelet and monocyte counts, and high concentrations of IL-6, IL-8 and sIL-2R predict OF in patients with community-acquired septic shock, and the combination of these markers may provide the means to identify sepsis patients who will develop OF.