Thomas Scheck

Postoperative pain and subcutaneous oxygen tension

Surgical patients randomly assigned to standard pain control had postoperative subcutaneous oxygen partial pressures that were significantly less than patients given better pain treatment. Our data suggest that control of postoperative pain is a major determinant of surgical-wound infection and should be given the same consideration as maintaining adequate vascular volume and normothermia.

Aggressive warming reduces blood loss during hip arthroplasty.

We evaluated the effects of aggressive warming and maintenance of normothermia on surgical blood loss and allogeneic transfusion requirement. We randomly assigned 150 patients undergoing total hip arthroplasty with spinal anesthesia to aggressive warming (to maintain a tympanic membrane temperature of 36.5°C) or conventional warming (36°C). Autologous and allogeneic blood were given to maintain a priori designated hematocrits. Blood loss was determined by a blinded investigator based on sponge weight and scavenged cells; postoperative loss was determined from drain output. Results were analyzed on an intention-to-treat basis. Average intraoperative core temperatures were warmer in the patients assigned to aggressive warming (36.5° ± 0.3° vs 36.1° ± 0.3°C, P < 0.001). Mean arterial pressure was similar in each group preoperatively, but was greater intraoperatively in the conventionally warmed patients: 86 ± 12 vs 80 ± 9 mm Hg, P < 0.001. Intraoperative blood loss was significantly greater in the conventional warming (618 mL; interquartile range, 480–864 mL) than the aggressive warming group (488 mL; interquartile range, 368–721 mL;P = 0.002), whereas postoperative blood loss did not differ in the two groups. Total blood loss during surgery and over the first two postoperative days was also significantly greater in the conventional warming group (1678 mL; interquartile range, 1366–1965 mL) than in the aggressively warmed group (1,531 mL; interquartile range, 1055–1746 mL, P = 0.031). A total of 40 conventionally warmed patients required 86 units of allogeneic red blood cells, whereas 29 aggressively warmed patients required 62 units (P = 0.051 and 0.061, respectively). We conclude that aggressive intraoperative warming reduces blood loss during hip arthroplasty. Implications Aggressive warming better maintained core temperature (36.5° vs 36.1°C) and slightly decreased intraoperative blood pressure. Aggressive warming also decreased blood loss by approximately 200 mL. Aggressive warming may thus, be beneficial in patients undergoing hip arthroplasty.

Ondansetron is no More Effective than Supplemental Intraoperative Oxygen for Prevention of Postoperative Nausea and Vomiting

Supplemental oxygen maintained during and for 2 h after colon resection halves the incidence of nausea and vomiting. Whether supplemental oxygen restricted to the intraoperative period is sufficient remains unknown. Similarly, the relative efficacy of supplemental oxygen and ondansetron is unknown. We tested the hypothesis that intraoperative supplemental oxygen reduces the incidence of postoperative nausea and vomiting. Patients (n = 240) undergoing gynecological laparoscopy were given a standardized isoflurane anesthetic. After induction, they were randomly assigned to the following three groups: routine oxygen administration with 30% oxygen, balance nitrogen (30% Oxygen group), supplemental oxygen administration with 80% oxygen, balance nitrogen (80% Oxygen group), and Ondansetron 8 mg (immediately after induction), combined with 30% oxygen, balance nitrogen (Ondansetron group). The overall incidence of nausea and/or vomiting during the initial 24 postoperative h was 44% in the patients assigned to 30% oxygen and 30% in the Ondansetron group, but only 22% in those given 80% oxygen. The incidence was thus halved by supplemental oxygen and was significantly less than with 30% oxygen. There were, however, no significant differences between the 30% oxygen and ondansetron groups, or between the ondansetron and 80% oxygen groups. We conclude that supplemental oxygen effectively prevents postoperative nausea and vomiting after gynecological laparoscopic surgery; furthermore, ondansetron is no more effective than supplemental oxygen. IMPLICATIONS Supplemental oxygen reduces the risk of postoperative nausea and vomiting (PONV) as well or better than 8 mg of ondansetron. Because oxygen is inexpensive and essentially risk-free, supplemental oxygen is a preferable method of reducing PONV.

Auricular Acupressure as a Treatment for Anxiety in Prehospital Transport Settings

Background Auricular acupuncture at the relaxation point has been previously shown to be an effective treatment for anxiety in the preoperative setting. The purpose of this prospective, randomized, blinded study was to determine whether auricular acupressure can reduce stress and anxiety during ambulance transport. Methods Patients who required ambulance transport secondary to medical conditions were randomized to receive auricular acupressure at the relaxation point (n = 17) or at a sham point (n = 19). A visual analog scale was used to assess state anxiety as well as patient anticipation of hospital medical treatment (estimated waiting period for treatment, anticipated pain during treatment, attitude toward the physicians, and treatment outcomes). These variables were assessed at baseline and on arrival to the hospital. Results Patients in the relaxation group reported significantly less anxiety than patients in the sham group on arrival to the hospital (visual analog scale mean ± SD: 37.6 ± 20.6 to 12.4 ± 7.8 mm vs. 42.5 ± 29.9 to 46.7 ± 25.9 mm, respectively;P = 0.002). Similarly, patient perception of pain during treatment (mean visual analog scale ± SD: 32.7 ± 27.7 to 14.5 ± 8.1 mm vs. 17.2 ± 26.1 to 28.8 ± 21.9 mm, respectively;P = 0.006) and treatment outcomes of their illnesses (mean visual analog scale ± SD: 46.7 ± 29.4 to 19.1 ± 10.4 mm vs. 35.0 ± 25.7 to 31.5 ± 20.5 mm, respectively;P = 0.014) were significantly more positive in the relaxation group than in the sham group. No differences were found in the other variables assessed. Conclusion It was concluded that auricular acupressure is an effective treatment for anxiety in prehospital emergency settings.

Prehospital Analgesia with Acupressure in Victims of Minor Trauma: A Prospective, Randomized, Double-blinded Trial

Untreated pain during the transportation of patients after minor trauma is a common problem in emergency medicine. Because paramedics usually are not allowed to perform invasive procedures or to give drugs for pain treatment, a noninvasive, nondrug-based method would be helpful. Acupressure is a traditional Chinese treatment for pain that is based on pain relief followed by a short mechanical stimulation of specific points. Consequently, we tested the hypothesis that effective pain therapy is possible by paramedics who are trained in acupressure. In a double-blinded trial we included 60 trauma patients. We randomly assigned them into three groups (“true points,” “sham-points,” and “no acupressure”). An independent observer, blinded to the treatment assignment, recorded vital variables and visual analog scales for pain and anxiety before and after treatment. At the end of transport, we asked for ratings of overall satisfaction. For statistical evaluation, one-way analysis of variance and the Scheffé F test were used. P < 0.05 was considered statistically significant. Morphometric and demographic data and potential confounding factors such as age, sex, pain, anxiety, blood pressure, and heart rate before treatment did not differ among the groups. At the end of transport we found significantly less pain, anxiety, and heart rate and a greater satisfaction in the “true points” groups (P < 0.01). Our results show that acupressure is an effective and simple-to-learn treatment of pain in emergency trauma care and leads to an improvement of the quality of care in emergency transport. We suggest that this technique is easy to learn and risk free and may improve paramedic-based rescue systems.

A Randomized Controlled Trial of Oxygen for Reducing Nausea and Vomiting During Emergency Transport of Patients Older Than 60 Years With Minor Trauma

OBJECTIVE To test the hypothesis that oxygen administration reduces nausea and vomiting in patients with minor trauma during ambulance transport. PATIENTS AND METHODS This study, conducted from January to April 2000, consisted of 100 patients older than 60 years with minor trauma, who were randomly assigned to breathe air or 100% oxygen at 10 L/min through a facemask during ambulance transport. A paramedic, blinded to treatment, recorded vomiting episodes during transport. Patients, also blinded to treatment, rated their levels of pain, nausea, vomiting, anxiety, and overall satisfaction with their care on 100-mm visual analog scales, with greater values indicating more intense sensation. Results from the 2 groups were compared with chi2 or unpaired 2-tailed t tests and presented as means +/- SDs. RESULTS Before randomization, patients subsequently assigned to receive oxygen had significantly greater pain and nausea. On arrival at the hospital, oxygen saturation was higher in the 50 patients given oxygen (99% +/- 1 % vs 96% +/- 2%; P<.001) than in the 50 patients who breathed air. Reported pain remained greater in the oxygen group. However, those given oxygen had less nausea (22 +/- 29 vs 54 +/- 38 mm; P<.001) and vomiting (4 vs 19 episodes; P<.001), lower heart rates (86 +/- 12 vs 94 +/- 13 beats/min; P<.001), and higher overall satisfaction scores (54 +/- 33 vs 33 +/- 23 mm; P<.001). CONCLUSION Our results indicate that supplemental oxygen during ambulance transport reduced nausea scores by 50% and decreased vomiting 4-fold. Consequently, patients reported greater satisfaction with their care. Thus, we recommend that patients be given supplemental oxygen during ambulance transport.

The influence of active warming on signal quality of pulse oximetry in prehospital trauma care.

UNLABELLED Victims of trauma such as contusions and simple fractures are usually transported by paramedics. Because many victims are intoxicated with alcohol or other drugs, they are vulnerable to some risk of inadequate respiration. Thus, their oxygenation is monitored by noninvasive pulse oximetry. We tested the hypothesis that active warming of the whole body during transport to the hospital can improve the reliability of arterial oxygen saturation (SpO(2)) monitoring. Twenty-four trauma patients transported to hospital were included in the study and randomly assigned to two groups: one group (n = 12) was covered with normal wool blankets, and the other group (n = 12) was treated with resistive heating blankets during transport. We recorded core temperature, shivering, skin temperature at the forearm and finger, SpO(2), and hemodynamic variables. Before randomization, both groups were comparable. On arrival at the hospital, the actively warmed patients had significantly warmer core (36.1 +/- 0.3 degrees C versus 35.5 +/- 0.3 degrees C; P < 0.001) and skin (34.1 +/- 1.5 degrees C versus 24.9 +/- 1.4 degrees C; P < 0.001) temperatures. In the actively warmed group, the pulse oximeter had significantly fewer alerts (31 versus 58) and a significantly less time of malfunction (146 +/- 42 s versus 420 +/- 256 s) and provided more constant measurements in the actively warmed group (P < 0.001). In this study we showed that active warming improves pulse oximeter monitoring quality in trauma patients during transport to the hospital. IMPLICATIONS Clinical trials show that pulse oximeter signal quality is limited by hypothermia. In this study we show that active whole-body warming of trauma victims improves monitoring quality during transport to the hospital.

Evaluation eines neuen Isoliersystems für Infusionslösungen in der präklinischen Traumaversorgung: Eine prospektive, randomisierte Studie

SummaryObjectiveInfusion of cold fluids in a patient leads to a reduction of core temperature and subsequently worsens hypothermia. We evaluated the efficacy of a newly developed self-warming insulation device for use in pre-hospital rescue.MethodsWe studied 50 trauma patients with a rescue time of more than one hour. They were randomly assigned to either infusions taken directly from a warming box in the ambulance (Group A, n=25) or infusions taken from the warming box and packed in an insulation device (Group B. n=25). We recorded ambient temperatures, infusion temperatures in five-minute-steps and transport duration of the infusions from the ambulance to the site of accident.ResultsAmbient temperatures and transport duration did not differ significantly between both groups. In Group A the infusion temperature decreased from 36.0±6.4°C to 19.8±6.8°C during the transport from the ambulance to the site of accident. In Group B infusion temperature decreased only about 1°C. In Group A the temperature of the infusion continued to decrease until the end of measurements. In contrast in Group B the infusion temperature even increased by 0.5°C over the measurement period. These differences between the two groups were statistically significant.ConclusionsOur data show that even pre-warmed infusions from a warming box cool down considerably before they can be given to the patient. A self-warming insulation device can stabilize infusion temperature even under extreme conditions of prehospital trauma careZusammenfassungHintergrundIm Rettungsdienst kann bei Verwendung kalter Infusionslösungen eine bestehende Hypothermie der Patienten aggraviert werden. In dieser Studie wurde die Wirksamkeit eines neuen Isoliersystems für Infusionen im Rettungsdienst getestet.MethodenWir untersuchten 50 Traumapatienten mit einer Einsatzzeit von mehr als einer Stunde. Wir randomisierten die Patienten auf zwei Gruppen. Gruppe A (n=25) erhielt aus der Wärmebox des Rettungswagens entnommene Infusionen; in der Gruppe B (n=25) wurden die Infusionen nach der Entnahme aus der Wärmebox in ein selbst wärmendes Isoliersystem verpackt und so appliziert. Wir erfassten Umgebungstemperaturen, Infusions temperaturen alle 5 Minuten, Wegzeiten und die Dauer der Flüssigkeitsgabe.ErgebnisseIn beiden Gruppen waren Wegzeiten, Umgebungstemperaturen und Infusionsdauer statistisch nicht signifikant unterschiedlich. In der Gruppe A sank die Infusionstemperatur während des Transports zum Patienten von 36,0±6,4°C auf 19,8±6,8°C. In Gruppe B sank die Temperatur um nur 1°C. In Gruppe A sank die Infusionstemperatur kontinuierlich weiter während die Flüssigkeit dem Patienten infundiert wurde. In Gruppe B stieg die Temperatur in dieser Phase wieder um 0,5°C. Diese Unterschiede zwischen den Gruppen waren statistisch signifikant.SchlussfolgerungenUnsere Daten zeigen, dass durch Wärmeboxen im Rettungsmittel zwar initial warme Infusionen zur Verfügung stehen, diese aber rasch am Weg zum Patienten und bei der Applikation abkühlen. Ein selbst wärmendes Isoliersystem verhindert diesen Abkühlprozess und erlaubt auch unter den schwierigen Bedingungen der Rettungsmedizin die körperwarme Infusionstherapie.