I need help with two questions which I posted at the end Based on the following
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I need help with two questions which I posted at the end Based on the following article The Comparison of Two Recovery Room Warming Methods for Hypothermia Patients Who Had Undergone Spinal Surgery Hsiu-Ling Yang, RN, BSN1, Hsiu-Fang Lee, RN, MSN2, Tsung-Lane Chu, RN, MSN3, Yu-Yun Su, RN, BSN4, Lun-Hui Ho, RN, MSN5, & Jun-Yu Fan, RN, PhD6 Below is the article : Abstract Purpose: The purpose of this study was to compare the time needed to reach a specified temperature and the efficiency of two warming methods–warm cotton blankets and a radiant warmer–for hypothermia patients in a postanes- thetic care unit (PACU) after spinal surgery. Design: This study was conducted according to a quasi-experimental design. Data were collected from a medical referral center in northern Taiwan. A total of 130 post–spinal surgery patients with hypothermia were recruited in the study. Methods: Of the 130 patients in the PACU, 65 were warmed by the radiant warmer (group R); whereas the other 65 patients were warmed by warm cot- ton blankets (group B). Tympanic temperature was measured for each patient every 10 min until it reached 36?C in the PACU. Analysis of covariance and generalized estimating equation regression analysis were performed to com- pare the time needed to reach a specified temperature and the efficiency of the two warming methods, respectively. Findings: Both groups were similar in their baseline characteristics. After ad- justing for temperature upon arrival at the PACU, group R needed a signifi- cantly shorter time for rewarming to 36?C than group B (F [1, 125] = 58.17,p < .001). The results of the generalized estimating equation also showed that the radiant warmer was more efficient than warm cotton blankets in increas- ing patients’ body temperatures to 36?C (?2 = 37.44, p < .001). None of the patients appeared to have wound infections, and there were no differences in the length of hospital stay or medical costs for current hospitalization in both groups. Conclusions: Using the radiant warmer may be a more efficient method than providing warm cotton blankets for warming post–spinal surgery hypothermia patients in the PACU. Clinical Relevance: For hospitals that are unable to use forced-air warming to warm postsurgical hypothermia patients in the PACU, the radiant warmer is a more efficient device to rewarm patients. Surgical patient hypothermia is a common phenomenon that may occur before, during, or after operations. Nu- merous preoperative, intraoperative, and postoperative hypothermia-related research studies have been con- ducted since 1980. Studies have reported that postoper- ative hypothermia, defined as having a core temperature of less than 36?C, occurs in 20% to 60% of all patients (Defina & Lincoln, 1998; Vaughan, Vaughan, & Cork, 1981). Spinal surgery involves a wide spectrum of pro- cedures during which the spinal cord, nerve roots, and blood vessels are frequently at risk for injury (Gonzalez, Jeyanandarajan, Hansen, Zada, & Hsieh, 2009). For pa- tients undergoing spinal surgery, intraoperative active warming is difficult, since they are placed in the prone position, which allows only the legs to be covered with warming devices (Murat, Berniere, & Constant, 1994). The following questions thus arise: what can the clini- cal staff do to decrease this inadvertent hypothermia after spinal surgery, and which of the devices readily available in hospitals are the most effective for rewarming these patients in the PACU? Literature ReviewThermoregulatory Mechanisms Humans are capable of maintaining homeostasis un- der fluctuating environmental conditions. For example, under normal circumstances, body temperature usually remains between 36.5?C and 37.5?C, with most changes being within 1?C (Cooper, 2006). The center for regula- tion of body temperature is situated in the hypothalamus, which is responsible for the precise balancing of heat pro- duction and conservation, heat loss, and redistribution of heat via three major thermoregulatory mechanisms: vasoconstriction, shivering, and sweating (Wagner, 2006a). In surgical patients undergoing general or major regional anesthesia, hypothermia develops immediately after the induction of anesthesia because heat is redis- tributed from the center of the body to the periphery (Wagner, 2006b). Anesthetic agents suppress thermoreg- ulatory control, especially heat production mechanisms, including blood vessel constriction and shivering (Sessler, 1997), leading to a greater chance of postoperative hypothermia. Temperature Changes During General Anesthesia In 1995, Matsukawa and colleagues observed healthy volunteers in a 22?C environment for 2.5 hr and found that their core temperature did not fluctuate sig- nificantly. However, at 1, 2, and 3 hr after general anesthesia, core body temperature dropped by 1.6?C ±0.3? C, 1.1? C ± 0.3? C, and 2.8? C ± 0.5? C, respectively. Sessler reported similar results in 2000. According to Sessler, there are three phases reflecting a typical hy- pothermic pattern during general anesthesia. During the first phase (1 hr of anesthesia), the patient’s core tem- perature drops by 0.5?C to 1.5? because heat is redis- tributed from the body to the extremities. In the second phase (2–3 hr of anesthesia), the temperature drops lin- early because the amount of heat lost is greater than that produced. In the third phase (3–5 hr of anesthesia), also known as the plateau phase, the temperature re- mains constant because the amount of heat lost is equal to that produced. In addition to anesthetic agents, extrin- sic factors such as a cold operating room environment, the length and type of surgical procedure, infusion of a cold sterile solution, and duration of exposure of the body cavity, as well as intrinsic factors such as patient health status, body size, and age, may place patients at risk for hypothermia (Scott, Leaper, Clark, & Kelly, 2001). Hypothermia Complications Numerous studies have reported that severe hypother- mia can cause physical discomfort and even health risks, including shivering, cardiac ischemia or arrest, de- creased immune function, increased blood loss and the need for a blood transfusion during the operation, in- creased wound infection, increased mortality, extended nursing time or admission due to organ failure, ex- tended retention time in the PACU, increased medi- cal costs, and decreased patient satisfaction (Buggy & Crossley, 2000; Fleisher, Metzger, Lam, & Harris, 1998; Flores-Maldonado, Medina-Escobedo, Rios-Rodriguez, & Fernandez-Dominguez, 2001; Frank et al., 1993; Hildebrand, Giannoudis, van Griensven, Chawda, & Pape, 2004; Kurz, Sessler, & Lenhardt, 1996; Leinonen, Leino-Kilpi, & Jouko, 1996; Panagiotis, Maria, Argiri, & Panagiotis, 2005; Schmied, Kurz, Sessler, Kozek, & Reiter, 1996). Thus, careful monitoring with regard to prevent- ing or decreasing the occurrence of hypothermia is an important duty of the clinical nursing staff in both the operating and recovery rooms. Warming Devices The use of rewarming devices for managing postop- erative hypothermia has been reported since 1986. In 1990, Sessler and Moayeri examined the efficacy of four postoperative warming devices, including a pair of 250- W infrared heating lamps, thermal ceiling MTC XI WL (500 W), circulating-water blankets, and forced-air warming (FAW) system, by measuring cutaneous heat loss or gain with thermal flux transducers. They also evaluated the correlation between forehead temperature and tympanic temperature in five healthy unanesthetized volunteers. The results showed that the use of FAW and circulating-water blankets decreased heat loss and raised skin temperature more than the other two radiant devices examined. In 1991, Giuffre, Finnie, Lynam, and Smith conducted a randomized controlled trial (RCT) to determine the ef- ficiency of three warming devices, specifically FAW, ra- diant heater lamps, and warmed cotton blankets, in 90 postoperative patients admitted to the PACU with a body temperature of 35?C. The results showed that there were no statistically significant differences in the mean time re- quired to reach the temperature criterion of 36?C for pa- tient discharge (p = .06) or in the mean time required to satisfy all criteria for discharge from the PACU (p =.71) among the groups warmed by FAW, radiant heater lamps, and warmed cotton blankets. Giuffre et al. further divided patients into shivering and nonshivering groups. Among patients who experienced shivering and were re- warmed by using the three devices, there were no differ- ences in either the mean rewarming time to reach 36?C (p = .91) or in the mean time required to satisfy all cri- teria for discharge from the PACU (p = .84). In patients in the nonshivering group, the FAW method was signif- icantly more rapid (mean of 121.7 min, p = .01) than both radiant heater lamps (184.7 min) and warmed cot- ton blankets (198.7 min). Weyland et al. (1994) conducted an RCT study to com- pare the rewarming rate efficiency of three warming de- vices (radiant heater, FAW, and cotton blankets) and to examine the effects of these devices on postopera- tive oxygen uptake in 35 awake, extubated, postopera- tive patients in the postoperative recovery room. Their results showed no significant differences in the central rewarming rate among the groups warmed with radiant heaters (n = 11), FAW (n = 12), and cotton blankets (n = 12), with rewarming rates of 0.81? C/hr, 0.76? C/hr, and 0.70?C/hr, respectively. The lack of statistical signif- icance in their study may be attributable to the small sample size. Torrie, Yip, and Robinson (2005) conducted an RCT to compare the efficacy and thermal comfort of radiant warming and FAW in patients undergoing transurethral resection of the prostate under spinal anes- thesia. The results showed that there was a statistically significant difference, but no clinically relevant differ- ence, in the final intraoperative rectal temperatures of pa- tients in the radiant warming and FAW groups, with tem- peratures of 36.1?C and 36.4?C, respectively (p = .003). Several clinical studies have demonstrated that FAW is effective in preventing intraoperative hypothermia or treating postoperative hypothermia (Andrzejowski, Hoyle, Eapen, & Turnbull, 2008; Bitner, Hilde, Hall, & Duvendack, 2007; Kimberger et al., 2008; Ng et al., 2003; Perl, Brauer, & Quintel, 2006; Wadhwa et al., 2007). The most effective strategy for reducing unplanned hypother- mia in surgical patients was to prewarm patients using an FAW device. However, Weirich (2008) indicated that FAW is not widely used because it causes contamina- tion, increases the ambient operating room temperature because of passive warming, and decreases recovery ef- forts because of inconsistent practice and lack of guid- ance. In the current study, the use of a forced-air device to rewarm patients post–spinal surgery was limited due to (a) restricted space in the preoperative waiting area; (b) rapid turnover rate; (c) the need for frequent ex- amination of the wound condition for bleeding; and (d) mandatory postsurgical assessment of neuromuscular function. Purpose In order to identify which device is more effective for warming patients after spinal surgery, we compared the rewarming time required and the efficiency of two warming methods–warm cotton blankets and a radiant warmer– for rewarming hypothermia patients in the PACU after spinal surgery. Methods Design, Setting, and Samples This study was conducted using a quasi-experimental design. Data were collected from a 3,477-bed medical re- ferral center in northern Taiwan. The referral center had 60 operating rooms, and 58,475 operations were per- formed in 2008. At this center, approximately 120 to 200 patients undergo spinal surgery each month, an average of 6 to 10 spinal surgery patients per day; thus, the num- ber of potentially eligible patients was more than suffi- cient to provide adequate data for the study. The PACU has 31 beds with a staff-to-patient ratio of 1:2. Patients who underwent spinal surgery (posterior approach only) between July and November 2008 and who met the fol- lowing criteria were considered to be potential partici- pants. To be included in this study, the patients were re- quired (a) to be older than 18 years and to have provided consent to participate in the study; (b) to have been under general anesthesia during surgery; (c) to be conscious and able to communicate; (d) to have no fever for 72 hr be- fore the study; (e) to have an operation time of 3 to 6 hr; (f) to have an operational wound of 10 to 15 cm; and (g) to have a tympanic temperature between 34?C and 35.5?C upon arrival at the PACU. Patients who were transferred to an intensive care unit were excluded from the study. Initially, 800 patients met criteria “a” through “f”, but among these, only 130 met criterion “g”. There- fore, a total of 130 post–spinal surgery hypothermia pa- tients were recruited to participate in the PACU. Among the 670 excluded patients, 122 were excluded because their operation time was either less than 3 hr (n = 80) or longer than 6 hr (n = 42), and 548 were excluded because their tympanic temperature was either below 34.0?C (n =80) or above 35.5?C (n = 468). The characteristics of the excluded patients were similar to those of the included patients. Measurements and Warming Devices The measurement procedures and warming devices used included a tympanic temperature thermometer, warm cotton blankets, a radiant warmer, and demo- graphic characteristics. Tympanic temperature thermometer. A CGM in- frared ear thermometer OPUS 1000 series with probe covers (Chang Gung Medical Supplies & Equipment Corp., Taipei, Taiwan) was used to check tympanic tem- perature at 10-min intervals during the data collection period. The OPUS 1000 series meets the American So- ciety for Testing and Materials standards E 1965–98 and NE 12470–5. The measuring range of the thermometer is between 20.0? C and 44.0? C, calibrated according to the manufacturer’s recommendations. The accuracy is ±0.2? C for temperatures in the range of 35.0? C to 42.0? C. Among temperature measurement methods, monitoring the tympanic temperature may most closely represent the core temperature since the measurement is the closest to the pulmonary artery (Chan, Ho, Huang, & Huang, 2000; Erickson, Meyer, & Ore, 1994; Ferrara-Love, 1991). Warm cotton blankets (Group B). All double- thickness green cotton blankets (150 cm × 90 cm, 0.5 kg/each) were kept in a blanket warmer maintained at 60?C for at least 1 hr before use. Immediately after the blanket was removed from the oven, its temperature was approximately 38?C. The PW810 Radiant Patient Warmer. was intro- duced in 1999 by the Fisher & Paykel Healthcare Cor- poration Limited (Auckland, New Zealand). This radiant warmer utilizes focused energy to raise skin tempera- ture rapidly and effectively. The transfer of radiant en- ergy requires direct exposure of the skin, and only the skin perpendicular to the heat source maximally absorbs energy. The facial skin has more capillary loops per unit area and generally more vessels per unit volume than other skin areas, and it is closer to the hypothalamus, which easily establishes the thermal gradient required for core rewarming. Using a skin sensor, the tempera- ture alarm was set at 1?C lower or higher than the set temperature 10 times per second to minimize accidental burning. Procedures This project was approved by the institutional review board of Chang Gung Memorial Hospital (IRB no. 97– 0521C). All patients hospitalized for spinal surgery were admitted 1 day prior to the operation. The investigators listed all potential candidates and examined the inclusion criteria. They visited each patient and explained the pur- pose of the study to the potential candidates and their families. On the day of operation, the investigators revis- ited the patients, invited potential candidates in the wait- ing area to participate in the study, and obtained written informed consent. Neither the patients nor the PACU staff members were blinded. Immediately following the oper- ation, all potential patients were fully covered by several warm blankets, and a comforter (a type of blanket mea- suring 200 cm × 160 cm, weighing 2 kg/each, filled with polyester fiber, with an outer shell covered by 100% cot- ton) was placed on top of the green cotton blankets to decrease heat convection. The patients were then trans- ported from the operating room to the PACU. The tem- perature was set at 19.0? C and 24.0? C in the OR and PACU, respectively. All potential patients had their tym- panic temperatures examined twice at 1-min intervals as the baseline temperature upon arrival at the PACU. They were supplied with supplemental oxygen until discharge from the PACU irrespective of whether they were shiver- ing. Their vital signs were examined at 10-min intervals, and a cotton cap was wrapped around their heads. At the time, only those potential patients with a tympanic tem- perature between 34.0? C and 35.5? C were included. The enrolled hypothermic spinal surgery patients were then assigned to either group B or group R on the basis of the last digit of their chart number. Odd and even num- bers were assigned to group B and group R, respectively. The investigators followed hospital guidelines in terms of the discharge criteria from the PACU. None of the en- rolled patients were discharged from the PACU until they (a) were fully awake and able to call for help if nec- essary; (b) had clear airways and could breathe sponta- neously; (c) were maintaining a blood oxygenation level of ?95% on room air; (d) had been physiologically sta- ble with acceptable vital signs for 15 to 30 min; (e) had a tympanic temperature of ? 36.0?C; (f) had no appar- ent postsurgical complications such as active bleeding; (g) had controlled and tolerable levels of postoperative pain 5 Warming Hypothermia Patients Yang et al. (the visual analog scale, which assesses pain level on a scale of 0–10, was used); (h) had minimal nausea and vomiting; and (i) had orders and prescriptions for all re- quired oxygen, intravenous fluids, and medicines. Be- sides the clinical criteria outlined above, our hospital also implements the Modified Aldrete Scoring System as a standardized written criteria as part of the decision to dis- charge a patient from the PACU (Aldrete, 1998). A score of 8 (maximum is 10) is needed to discharge a patient. Lastly, an anesthesiologist’s approval is required for each patient’s discharge. Groups Patients in group B received three warm cotton blan- kets fully covering them from the neck to the toes. A comforter was placed on top of the blankets at all times during the PACU period to decrease heat conduction with the PACU environment. The blanket was placed by re- moving the topmost comforter, placing three new warm cotton blankets on the top of the old cooled blankets, re- moving the three old cooled blankets simultaneously, and finally placing a fresh comforter on top of the new warm blankets. The three warmed blankets were replaced si- multaneously every 30 min, although the frequency of blanket changes was not clearly defined in previous stud- ies. On the basis of the study by Giuffre et al. (1991), as well as personal clinical experience, the investigators de- cided to replace the three blankets every 30 min in order to keep the blankets from cooling too quickly. The patients in group R initially also received three warm cotton blankets fully covering them from the neck to the toes. A comforter was placed on top of the blan- kets all the time but was not replaced during the patient’s stay in the PACU. Group R also received a PW81 radi- ant warmer, with an irradiance of 32 mW/cm2 at 100% heater power mounted 68 cm above the head (including facial area) and neck area. The temperature alarm was set at 37.5?C to minimize burn accidents. During tem- perature measurements, the radiant warmer was moved to the patient’s other side to eliminate the possible ef- fect of the warmer on the thermometer. The investigators measured tympanic temperature at 10-min intervals us- ing the same CGM infrared ear thermometer OPUS 1000 series on the same ear, until the tympanic temperature reached 36.0?C. Data Analysis The data were analyzed using SPSS version 17 software for Windows (SPSS Inc., Chicago, IL, USA), and the sig- nificance level was set at p < .05. Besides the descriptive statistics, an independent t-test, analysis of covariance (ANCOVA), and generalized estimating equation (GEE) regression analysis were used to compare the time needed in the PACU and the efficiency of the two warming meth- ods in increasing patients’ body temperatures to 36.0?C. Results Sample Description In this study, we enrolled a total of 130 patients (53.8% female, n = 70) with a mean age of 67.0 ±13.3 years (range 19.2–86.2 years). Laminectomy was the most common surgical procedure (n = 66, 50.8%), followed by spinal fusion (n = 57, 43.8%) and discec- tomy (n = 7, 5.4%). More than half (85/130, 65.4%) of the patients did not have any comorbidities. The char- acteristics of the two groups were similar (Table 1). We further examined the groups to determine whether there were differences in the patient characteristics at different temperatures. Both groups were divided into three different temperature subgroups on the basis of the baseline temperature at the time of admission to the PACU: 34.00? C to 34.50? C (low), 34.51? C to 35.00? C (medium), and 35.01? C to 35.50? C (high). A two-way analysis of variance and chi-square test were performed to examine any differences in characteristics among these three different subgroups between the two treat- ment groups. Importantly, no significant differences were found. Time Spent in the PACU The time required to reach 36?C ranged from 10 to 120 min (mean 43.54 ± 27.12 min) for group R and 10 to 160 min (mean 76.77 ± 36.19 min) for group B. The time needed to reach a temperature of 36.0?C was significantly shorter for group R than for group B (t(128) = 5.92,p < .001). The data were examined further to determine whether the time for a temperature of 36.0?C at different temperatures was different. The results showed that all three temperature subgroups (low, medium, and high) in group B needed a significantly longer time to reach 36.0?C (p < .001) than any subgroup of group R, with ratios of 1.55 (114.12 vs. 73.75 min), 1.50 (74.80 vs. 50.00 min), and 2.12 (51.30 vs. 24.19 min), respectively. Even though there were no differences in the basic characteristics of the three subgroups or between the two treatment groups, potential confounders such as age, sex, weight, health status, amount of blood loss during the operational period, amount of solution used during the operation, length of the operation, temperature at extu- bation, and temperature upon arrival at the PACU might 6 Yang et al. Table 1. Characteristics of the Two Groups Characteristics Age (years) Weight (kg) Gender Male Female Spinal surgery method Laminectomy Spinal fusion Discectomy Spinal surgery location Cervical Thoracic Lumbar No. of comorbidities 0 1 2 3 Usage of warmer lamp during operation No Yes Doses of anesthesia medication Atropine (mg)? Fentanyl (?g)? Propofol (mg) Xylocaine (mg) Cisatracurium (mg) Citosol (mg) Rocuronium (mg) Amount of blood loss Amount of solution?Length of operation (min) Tympanic temperature ?C Waiting room Initial operation Extubation Admitted to PACU Discharge from PACU Wound infection Length of stay in hospital (days) Medical cost during hospitalization (NTD) Warm cotton blankets (n = 65) 62.01 ± 13.67 61.30 ± 12.08n (%) 29 (22.2) 36 (27.7) 34 (26.2) 26 (20.0) 5 (3.8) 11 (8.5) 3 (2.3) 51 (39.2) 38 (29.2) 25 (19.2) 2 (1.5) 0 (0) 3 (2.3) 62 (47.4) 0.16 ± 0.21 166.92 ± 54.68 64.77 ± 48.16 8.85 ± 9.95 7.43 ± 5.04 68.85 ± 93.34 14.77 ± 23.66 478.92 ± 450.62 769.23 ± 251.20 254.18 ± 47.07 36.38 ± 0.40 35.69 ± 0.45 34.71 ± 0.45 34.86 ± 0.42 36.18 ± 0.21 0 (0) 10.46 ± 5.18 112,440.62 ± 55,688.91 Radiant warmer (n = 65) Mean ± SD 63.48 ± 13.06 65.06 ± 11.55 31 (23.8) 34 (26.2) 32 (24.2) 31 (23.8) 2 (1.5) 13 (10.0) 3 (2.3) 49 (37.7) 47 (36.2) 17 (13.1) 0 (0) 1 (0.8) 8 (6.2) 67 (43.8) Mean ± SD0.11 ± 0.19 160.77 ± 29.96 70.77 ± 46.61 13.85 ± 18.34 8.59 ± 4.61 56.15 ± 92.28 10.77 ± 22.73 551.69 ± 554.81 676.92 ± 240.94 268.18 ± 50.43 36.35 ± 0.47 35.62 ± 0.52 34.70 ± 0.46 34.92 ± 0.49 36.25 ± 0.31 n (%) 0 (0) Mean ± SD9.82 ± 7.00 105,495.75 ± 75,209.42 Warming Hypothermia Patients Total (N = 130) 62.75 ± 13.33 63.18 ± 11.92 60 (46.2) 70 (53.8) 66 (50.8) 57 (43.8) 7 (5.4) 24 (18.5) 6 (4.6) 100 (76.9) 85 (65.4) 42 (42.3) 2 (1.5) 1 (0.8) 11 (8.5) 129 (91.5) 0.13 ± 0.20 163.85 ± 44.03 67.77 ± 47.30 11.35 ± 14.91 8.01 ± 4.84 62.50 ± 92.67 12.77 ± 23.20 515.31 ± 504.77 723.08 ± 249.51 261.18 ± 49.09 36.37 ± 0.44 35.65 ± 0.49 34.70 ± 0.45 34.89 ± 0.44 36.21 ± 0.27 0 (0) 10.14 ± 6.14 108,968.18 ± 66,008.05 Note. NTD = New Taiwan Dollar; PACU, postanesthesia care unit. ? p < .05. place patients at risk for hypothermia and could influence the length of stay in the PACU. Significant relationships were found between the length of stay in the PACU and the temperature at extubation (r = ?0.45, p < .01), and between the length of stay in PACU and the tempera- ture upon arrival at the PACU (r = ?0.68, p < .01). The investigators decided that only the “temperature upon ar- rival at the PACU” should be defined as a covariate in the current study because this temperature most closely reflected the patients’ body temperatures at that specific 7 Warming Hypothermia Patients Yang et al. Table 2. Rewarming Rates of the Two Warming Methods, and Time Needed Rewarming to 36? C in the Three Temperature Subgroups Groups nWarm cotton blankets 65 Radiant warmer 65 34.00–34.50?C (low) Warm cotton blankets 17 Radiant warmer 16 34.51–35.00?C (medium) Warm cotton blankets 25 Radiant warmer 18 35.01–35.50?C (high) Warm cotton blankets 23 Radiant warmer 31 Average rewarming rate (mean ?C/hr) 1.03 1.83 Time needed rewarming to 36?C (mean min ± SD) 76.77 ± 36.19 43.54 ± 27.12 114.12 ± 30.04 73.75 ± 23.06 74.80 ± 24.34 50.00 ± 16.80 51.30 ± 26.51 24.19 ± 15.66 Time needed rewarming to 36.0?C (B/R ratio) 1.76 1.55 1.50 2.12 t p 5.92 <.001 4.22 <.001 3.72 <.001 4.37 <.001 Note. B/R ratio = ratio of warm cotton blankets to radiant warmer. time point. ANCOVA showed that the main effects of the two rewarming methods were significantly different af- ter controlling for the “temperature upon arrival at the PACU,” F (1, 125) = 58.17, p < .001. Group R needed less time for rewarming to 36.0?C than group B (46.17 vs. 76.06 min, respectively, p < .001). Efficiency of the Two Warming Methods The average rate of rewarming to a temperature of 36.0? C was 1.83? C/hr and 1.03? C/hr, respectively, for group R and group B. In the current study, the investi- gators examined each enrolled participant’s temperature every 10 min; that is, each patient may have had a differ- ent temperature measurement frequency while staying in the PACU. GEE analysis was chosen to resolve the cluster data issue and to analyze the efficiency of the two warm- ing methods because it suited the current study design (repeated measurements) and had the advantage of a ro- bust standard error (within-subject residual). The results showed that group R exhibited a higher warming rate than group B (? 2 = 37.44, p < .001). In summary, the ra- diant warmer was more efficient than warm cotton blan- kets in raising patients’ body temperatures post–spinal surgery. Table 2 presents the time needed rewarming and the efficiency of the two warming methods. Discussion Efficiency of the Warming Methods The current study shows that the radiant warmer helped increase patients’ body temperatures to 36.0?C faster than the warmed cotton blankets. Despite adjusting for the covariate (temperature upon arrival to the PACU), the results of the present study were not consistent with those of a previous study by Giuffre et al. (1991). This in- consistency might be attributable to the lack of definition of “post-surgery patients” in the study by Giuffre et al., which may have caused large variability within the three study groups and therefore diminished the effects of in- tervention. In terms of efficiency (or rewarming rate), the current study also differs from the study by Weyland et al. conducted in 1994. In the present study, the rewarm- ing rate was higher when a radiant warmer was used than when warm cotton blankets were used (1.83?C/hr vs. 1.03?C/hr), while in the study by Weyland et al., no significant differences were found between the rates of rewarming by the radiant warmer and the cotton blan- kets (0.81?C/hr and 0.70?C/hr, respectively). The lack of statistical significance in the study by Weyland et al. may be due to the small sample size (N = 35). From a med- ical costs perspective, delayed recovery in the PACU is expensive because the medical costs incurred are simi- lar to those incurred in the intensive care unit. In the current study, use of the radiant warmer device did re- sult in greater efficiency of rewarming and a shorter re- covery time in the PACU than use of warm cotton blan- kets to raise the body temperature of post–spinal surgery patients, and this might have decreased medical costs in part because of the shorter length of stay in the PACU. As an added advantage, the radiant warmer is more ecolog- ically friendly than comparable electrical warming meth- ods such as FAW, which is more expensive and requires large amounts of water and detergents to wash. Study Limitations and Suggestions The primary limitation of this study is that these find- ings cannot be generalized since only individuals who 8 Yang et al. Warming Hypothermia Patients had undergone spinal surgery were selected. It is not clear whether these findings would be clinically relevant to pa- tients undergoing different types of surgery, such as open thoracic or open abdominal surgery. The prevalence of post–spinal surgery hypothermia in the current study was underestimated (reported to be 130 of 800 = 16.25%), because some patients experiencing hypothermia follow- ing spinal surgery were not included, such as patients with operation times longer than 6 hr and patients with tympanic temperatures below 34.0?C, as mentioned in the Design, Setting, and Samples section. In terms of post- operative outcome parameters, blood loss during the op- eration, length of stay in the PACU, wound infection, mortality during hospitalization, and medical costs were measured. During the study period, no patients sponta- neously commented that the radiant warmer provided any thermal comfort, but patients in the warm cotton blankets group did complain that the blankets cooled rapidly. The investigators believe that patients likely felt more thermal comfort when the radiant warmer was used than when the warm cotton blankets were used, but this aspect was not systemically investigated. For fu- ture studies, parameters such as body mass index, degree of shivering, thermal comfort, patient satisfaction, and postoperative pain levels should be included for detailed investigation. Conclusions The results presented in this report showed that the radiant warmer device required significantly less time for rewarming and was more efficient in raising body temperature than warm cotton blankets in post–spinal surgery hypothermia patients. Recent clinical studies have provided evidence that using FAW during the intra- operative period may prevent hypothermia, thus avoid- ing serious postoperative complications. Unfortunately, FAW equipment is still unavailable in many hospitals be- cause of certain limitations mentioned in the objectives subsection. For hospitals or facilities that are unable to use FAW to warm surgical patients during the periop- erative period, the present results suggest an evidence- based reason to choose a radiant warming device to ef- ficiently warm post–spinal surgery hypothermia patients in the PACU. Questions --- Was there a conceptual/theoretical framework articulated, and, if so, is it appropriate? If not, is the absence of one justified? Were appropriate procedures used to safeguard the rights of study participants? Was the study externally reviewed by an IRB/ethics review board? Was the study designed to minimize risks and maximize benefits?
Explanation / Answer
1) No theoretical framework was not articulated and absence is also not justified
2) yes ,as patient consent was taken and also critically ill and peadiatric patients were excluded
3) yes the study was reviewed by institutional review board
4) Yes the study is beneficial as it helps to identify the better way to minimize post operative hyperthermia and the risks were also minimized as critically I'll and paediatric patients were excluded, also none of the patient's were deprived of any treatment they need.