Editor's Choice - Prolonged ICU Length of Stay after AAA Repair: Analysis of Time Trends and Long-term Outcome.

OBJECTIVE: The aim of the study was to investigate the frequency and outcome of prolonged intensive care unit (ICU) length of stay (LOS) after abdominal aortic aneurysm (AAA) repair in the endovascular era. METHODS: All patients operated on for AAA between 1999 and 2013 at Uppsala University hospital were identified. Data were retrieved from the Swedish Vascular registry, the Swedish Intensive Care registry, the National Population registry, and case records. Prolonged ICU LOS was defined as ≥ 48 h during the primary hospital stay. Patients surviving ≥ 48 h after AAA surgery were included in the analysis. RESULTS: A total of 725 patients were identified, of whom 707 (97.5%) survived ≥ 48 h; 563 (79.6%) underwent intact AAA repair and 144 (20.4%) ruptured AAA repair. A total of 548 patients (77.5%) required < 48 h of intensive care, 115 (16.3%) 2-6 days and 44 (6.2%) ≥ 7 days. The rate of prolonged ICU LOS declined considerably over time, from 41.4% of all AAA repairs in 1999 to 7.3% in 2013 (p < .001) whereas the use of endovascular aortic repair (EVAR) increased from 6.9% in 1999 to 78.0% in 2013 (p < .001). The 30 day survival rate was 98.2% for those with < 48 h ICU stay versus 93.0% for 2-6 days versus 81.8% for ≥ 7 days (p < .001); the corresponding 90 day survival was 97.1% versus 86.1% versus 63.6% (p < .001) respectively. For patients surviving 90 days after repair, there was no difference in long-term survival between the groups. CONCLUSION: During the period of progressively increasing use of EVAR, a simultaneous significant reduction in frequency of prolonged ICU LOS occurred. Although prolonged ICU LOS was associated with a high short-term mortality, long-term outcome among those surviving the initial 90 days was less affected.

Intranasal cooling with or without intravenous cold fluids during and after cardiac arrest in pigs.

BACKGROUND: Intranasal balloon catheters circulated with cold saline have previously been used for the induction and maintenance of selective brain cooling in pigs with normal circulation. In the present study, we investigated the feasibility of therapeutic hypothermia initiation, maintenance and rewarming using such intranasal balloon catheters with or without addition of intravenous ice-cold fluids during and after cardiac arrest treatment in pigs. MATERIAL AND METHODS: Cardiac arrest was induced in 20 anaesthetised pigs. Following 8 min of cardiac arrest and 1 min of cardiopulmonary resuscitation (CPR), cooling was initiated after randomisation with either intranasal cooling (N) or combined with intravenous ice-cold fluids (N+S). Hypothermia was maintained for 180 min, followed by 180 min of rewarming. Brain and oesophageal temperatures, haemodynamic variables and intracranial pressure (ICP) were recorded. RESULTS: Brain temperatures reductions after cooling did not differ (3.8 +/- 0.7 degrees C in the N group and 4.3 +/- 1.5 degrees C in the N+S group; P=0.47). The corresponding body temperature reductions were 3.6 +/- 1.2 degrees C and 4.6 +/- 1.5 degrees C (P=0.1). The resuscitation outcome was similar in both groups. Mixed venous oxygen saturation was lower in the N group after cooling and rewarming (P=0.024 and 0.002, respectively) as compared with the N+S group. ICP was higher after rewarming in the N group (25.2 +/- 2.9 mmHg; P=0.01) than in the N+S group (15.7 +/- 3.3 mmHg). CONCLUSIONS: Intranasal balloon catheters can be used for therapeutic hypothermia initiation, maintenance and rewarming during CPR and after successful resuscitation in pigs.

Intranasal selective brain cooling in pigs.

BACKGROUND: Special clinical situations where general hypothermia cannot be recommended but can be a useful treatment demand a new approach, selective brain cooling. The purpose of this study was to selectively cool the brain with cold saline circulating in balloon catheters introduced into the nasal cavity in pigs. MATERIAL AND METHODS: Twelve anaesthetised pigs were subjected to selective cerebral cooling for a period of 6 h. Cerebral temperature was lowered by means of bilaterally introduced nasal balloon catheters perfused with saline cooled by a heat exchanger to 8-10 degrees C. Brain temperature was measured in both cerebral hemispheres. Body temperature was measured in rectum, oesophagus and the right atrium. The pigs were normoventilated and haemodynamic variables were measured continuously. Acid-base and electrolyte status was measured hourly. RESULTS: Cerebral hypothermia was induced rapidly and within the first 20 min of cooling cerebral temperature was lowered from 38.1+/-0.6 degrees C by a mean of 2.8+/-0.6 to 35.3+/-0.6 degrees C. Cooling was maintained for 6 h and the final brain temperature was 34.7+/-0.9 degrees C. Concomitantly, the body temperature, as reflected by oesophageal temperature was decreased from 38.3+/-0.5 to 36.6+/-0.9 degrees C. No circulatory or metabolic disturbances were noted. CONCLUSIONS: Inducing selective brain hypothermia with cold saline via nasal balloon catheters can effectively be accomplished in pigs, with no major disturbances in systemic circulation or physiological variables. The temperature gradients between brain and body can be maintained for at least 6 h.

Brain temperature in volunteers subjected to intranasal cooling.

PURPOSE: Intranasal cooling can be used to initiate therapeutic hypothermia. However, direct measurement of brain temperature is difficult and the intra-cerebral distribution of temperature changes with cooling is unknown. The purpose of this study was to measure the brain temperature of human volunteers subjected to intranasal cooling using non-invasive magnetic resonance (MR) methods. METHODS: Intranasal balloons catheters circulated with saline at 20°C were applied for 60 min in ten awake volunteers. No sedation was used. Brain temperature changes were measured and mapped using MR spectroscopic imaging (MRSI) and phase-mapping techniques. Heart rate and blood pressure were monitored throughout the experiment. Rectal temperature was measured before and after the cooling. Mini Mental State Examination (MMSE) test and nasal inspection were done before and after the cooling. Questionnaires about the subjects' personal experience were completed after the experiment. RESULTS: Brain temperature decrease measured by MRSI was -1.7 ± 0.8°C and by phase-mapping -1.8 ± 0.9°C (n = 9) at the end of cooling. Spatial distribution of temperature changes was relatively uniform. Rectal temperature decreased by -0.5 ± 0.3°C (n = 5). The physiological parameters were stable and no shivering was reported. The volunteers remained alert during cooling and no cognitive dysfunctions were apparent in the MMSE test. Postcooling nasal examination detected increased nasal secretion in nine of the ten volunteers. Volunteers' acceptance of the method was good. CONCLUSION: Both MR techniques revealed brain temperature reductions after 60 min of intranasal cooling with balloons circulated with saline at 20°C in awake, unsedated volunteers.