Anaesthetic Room Research Articles

Preoperative hair removal to reduce surgical site infection

Although preparation of people for surgery has traditionally included removal of hair from the incision site, some studies claim that preoperative hair removal is harmful, causes surgical site infections (SSIs), and should be avoided. To determine if routine pre-operative hair removal (compared with no removal) and the timing or method of hair removal influence rates of SSI.. For this second update we searched the Cochrane Wounds Group Specialised Register (searched 12 August 2011); The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 3); Ovid MEDLINE (1950 to August Week 1 2011); Ovid MEDLINE (In-Process & Other Non-Indexed Citations August 11, 2010); Ovid EMBASE (1980 to 2011 Week 31) and EBSCO CINAHL (1982 to 11August 2011). No date or language restrictions were applied. Randomised controlled trials (RCTs) or quasi randomised trials (QRCTs) that compared:1) hair removal with no hair removal; 2) different methods of hair removal; 3) hair removal at different times before surgery; and, 4) hair removal in different settings (e.g. ward, anaesthetic room). Three authors independently assessed relevance and quality of each trial. Data were extracted independently by two authors and cross-checked. We included 14 trials (17 comparisons) in the review; three trials involved multiple comparisons. Six trials, two of which had three comparison arms, (972 participants) compared hair removal (shaving, clipping, or depilatory cream) with no hair removal and found no statistically significant difference in SSI rates however the comparison is underpowered. Three trials (1343 participants) that compared shaving with clipping showed significantly more SSIs associated with shaving (RR 2.09, 95% CI 1.15 to 3.80). Seven trials (1213 participants) found no significant difference in SSI rates when hair removal by shaving was compared with depilatory cream (RR 1.53, 95% CI 0.73 to 3.21), however this comparison is also underpowered. One trial compared two groups that shaved or clipped hair on the day of surgery compared with the day before surgery; there was no statistically significant difference in the number of SSIs between groups however this comparison was also underpowered.We identified no trials that compared clipping with depilatory cream; or investigated application of depilatory cream at different pre-operative time points, or hair removal in different settings (e.g. ward, anaesthetic room). Whilst this review found no statistically significant effect on SSI rates of hair removal insufficient numbers of people have been involved in this research to allow confidence in a conclusion. When it is necessary to remove hair, the existing evidence suggests that clippers are associated with fewer SSIs than razors. There was no significant difference in SSI rates between depilatory creams and shaving, or between shaving or clipping the day before surgery or on the day of surgery however studies were small and more research is needed.

Donation after circulatory death – a new role for the anaesthetist?

Donation after circulatory death – a new role for the anaesthetist?

Critical incident reports concerning anaesthetic equipment: analysis of the UK National Reporting and Learning System (NRLS) data from 2006-2008*

Anaesthetic equipment plays a central role in anaesthetic practice but brings the potential for malfunction or misuse. We aimed to explore the national picture by reviewing patient safety incidents relating to anaesthetic equipment from the National Reporting and Learning System for England and Wales between 2006 and 2008. We searched the database using the system's own classification and by scrutinising the free text of relevant incidents. There were 1029 relevant incidents. Of these, 410 (39.8%) concerned patient monitoring, most commonly screen failure during anaesthesia, failure of one modality or failure to transfer data automatically from anaesthetic room to operating theatre. Problems relating to ventilators made up 185 (17.9%) of the reports. Sudden failures during anaesthesia accounted for 142 (13.8%) of these, with a further 10 cases (0.9%) where malfunction caused a sustained or increasing positive pressure in the patient's airway. Leaks made up 99 (9.6%) of incidents and 53 (5.2%) of incidents arose from the use of infusion pumps. Most (89%) of the incidents caused no patient harm; only 30 (2.9%) were judged to have led to moderate or severe harm. Although equipment was often faulty, user error or unfamiliarity also played a part. A large variety of causes led to a relatively small number of clinical scenarios, that anaesthetists should be ready, both individually and organisationally, to manage even when the cause is not apparent. We make recommendations for enhancing patient safety with respect to equipment. You can respond to this article at http://www.anaesthesiacorrespondence.com.

Accuracy of ten isoflurane vaporisers in current clinical use

There is a lack of independent data regarding the accuracy of isoflurane vaporisers in current clinical use. We studied the accuracy of 10 isoflurane vaporisers (six Penlon Sigma Delta, four Datex-Ohmeda Isotec 5) taken from our operating theatres and anaesthetic rooms. Isoflurane output was measured at a range of fresh gas flow rates using both 100% oxygen and a 1:2 oxygen:nitrous oxide mixture as carrier gas. Within a clinical range of fresh gas flow rates (1-6 l.min(-1)) the worst relative output deviation of each vaporiser was at least ±20%, with under-delivery of isoflurane being commoner than over-delivery. Relative output deviation ranged from -62% to +21%, which could lead to a risk of awareness or overdose. Despite the existence of an in-house calibration schedule, the vaporisers we found in current clinical use under- or occasionally over-delivered isoflurane to a dangerous and unpredictable extent.

Theater Sending: How Long Does It Take and What Is the Cost of Late Starts?

Last minute cancellations of scheduled surgery are a waste of health care resources and an emotional burden on patients. A common reason for cancellation is poor theater time utilization. Several studies have demonstrated that in some cases 50% of lists overran their scheduled time and more than 40% started late. In a recent prospective study of 55 elective gynecological operations, 25% of the theater session was wasted by delays related to transfer of patients to and from the operating theater; the median waiting time between cases was 22.5 minutes for surgeons and 7 minutes for anesthetists. The aim of this retrospective study was to examine the theater transit of patients through theaters and estimate the cost of delays, especially the cost of late starts. The study subjects were 238 patients undergoing elective gynecological operations during a 3-month period in 2008 at a single hospital. After exclusions, 164 patients were included in the final analysis. Primary study outcome measures included time to send, time for anesthesia, and procedure time. Secondary outcome measures included time to send for the first patient (calculated as waiting time resulting from late starts) and the estimated cost of late starts. The mean time to send (time between sending and arrival in anesthetic room) was 19 ± 8.1 minutes; the 95% confidence interval [CI] was 18 to 20. The mean time for anesthesia (time between arrival in anesthesia room and arrival in theater) was 9 ± 6.4 minutes (95% CI: 8–10). The mean procedure time (time between arrival in theater and end of procedure) was 60 ± 35 minutes (95% CI: 55–65). The mean time to send for the first patient on the morning list (representing the mean wait time of the surgical team for the first patient) was 20 ± 9.83 minutes (95% CI: 17–23). The delayed arrival of the first patient resulted in a late start in 93% of morning lists. The mean wait time of the surgical team after the first patient on the morning list was due to start was 22 ± 19 minutes (95% CI: 17–27). During the 3-month study period, the total time wasted as a result of late starts was 910 minutes (15 h) at an estimated cost of £3640. The investigators conclude from these findings that sending patients 30 minutes before the list is due to start could increase theater efficiency and save 15 hours of currently wasted time.

Consent issues for children: a law unto themselves?

Obtaining valid, informed consent to medical treatment is a fundamental principle of modern medical practice. A thorough understanding of the differences between obtaining valid consent in adult and paediatric practice is essential if clinicians are to administer anaesthesia for patients aged ,18 yr. Consent must be voluntary and not influenced by external pressures, inducements, or coercion and should have a background of sufficient information and adequate understanding. Although this statement can be applied to the majority of adult patients, it is certainly not the case for infants and neonates. Older children may have some understanding of the treatment they are to have but lack the maturity to be competent enough to fully understand. These children may co-operate cheerfully in the anaesthetic room but it must be understood that this is assent to treatment and not consent. Assent and implied consent are sometimes considered interchangeable in adult practice but this cannot be the case for non-competent children. Anaesthetists should therefore have fully explained any interventions to those with parental responsibility for a non-competent before they enter the anaesthetic room. A simple example of which might be the necessity to change between an i.v. and gaseous induction depending on the co-operation of the child and the practitioner’s skill at cannulation. The age at which a child is generally considered competent to give consent for medical treatment is 16 yr in the UK. Younger children may have sufficient understanding to give fully informed consent for minor procedures but will probably still lack sufficient maturity to understand the implications of more serious, lifethreatening surgery. In all of these situations, somebody has to act on behalf of the child to give consent and that person is said in law to have ‘parental responsibility’. The law pertaining to who does and who does not have parental responsibility is complicated and often poorly understood and this review will attempt to clarify the situation. It will not address the issue of written consent for anaesthesia. The reader is urged to follow local policy in this regard but is reminded that a signed consent form is only a record of the consent process and whether the consent is oral or written, clinicians must know whether the person they are talking to has the authority in law to give consent.

Sugammadex for rocuronium rapid sequence induction

We read with interest and some concern the study investigating the simulated use of sugammadex in the ‘can’t intubate, can’t ventilate’ situation [1]. We agree that the use of sugammadex is not common and that anaesthetists are not immediately familiar with the doses. Moreover, we cannot see this changing in the current financial climate. We also agree that calculating and administering the correct dose is essential, but we believe that the authors’ suggestion of storing sugammadex in all anaesthetic trolleys is not likely to happen in our hospital. We have a stock in a central store, which is at most fifty yards from each of the twelve theatres in our theatre suite. We cannot envisage that our hospital would purchase sufficient drug to have sugammadex available in appropriate quantities for high-dose reversal in all of these theatres. We have already noted that this small store can be wasted as vials become out of date due to infrequent use. When undertaking rapid sequence induction with rocuronium, our practice is to calculate the appropriate dose of sugammadex before induction of anaesthesia, and to have this ready in the anaesthetic room with a labelled syringe to hand. We do not draw up the drug unless it is required. This reduces time that may be wasted trying to find and decide on the correct dose of the drug. We feel this addresses the problem without wasting large amounts of an expensive drug. It also allows us to become increasingly familiar with calculating the dose of suggamadex for use in an emergency ‘can’t intubate, can’t ventilate’ situation in case the real scenario arises. No external funding and no competing interests declared. Previously posted at the Anaesthesia Correspondence website: http://www.anaesthesiacorrespondence.com.

Bacteremia during Adenoidectomy: A Comparison of Suction Diathermy Adenoid Ablation and Adenoid Curettage

Transient bacteremia is induced by adenoidectomy when the integrity of the nasopharyngeal membrane is broken. The aim of this study was to determine the incidence of bacteremia in patients undergoing adenoidectomy, to identify the causative organisms, and to compare the incidences of bacteremia between the two techniques suction diathermy and curettage. A prospective single-blind randomized trial was performed. Sixty-four patients between the ages of 2 and 13 years who were undergoing adenoidectomy were included in the study. Exclusion criteria included antimicrobial therapy in the immediate preoperative period and concurrent respiratory tract infection or pyrexia. Patients were randomized in the anesthetic room to either suction diathermy or curettage. Venous blood samples for culture were obtained 30 seconds after the procedure began (intraoperative sample) and 2 minutes after removal of the adenoid tissue (postoperative sample). Postoperative complications were recorded, and all patients were followed in the outpatient department. Twenty-six patients underwent adenoidectomy by suction diathermy, and 38 underwent adenoidectomy by curettage. In the suction diathermy group, 38.5% of intraoperative and 19.2% of postoperative blood cultures had a positive result for bacteremia. In the curettage group, 31.6% of intraoperative and 23.6% of postoperative blood cultures had a positive result for bacteremia. There was no significant difference between the two groups. The techniques were equivalent in terms of postoperative complications. Gram-positive cocci were the most commonly isolated organisms. A transient bacteremia exists after pediatric adenoidectomy, but does not correlate with symptoms or signs. Neither suction diathermy adenoidectomy nor curettage adenoidectomy offers a particular advantage in terms of decreasing the incidence of bacteremia.

Unnecessary electricity consumption by anaesthetic room monitors

Unnecessary electricity consumption by anaesthetic room monitors

Intralipid reverses coma associated with zopiclone and venlafaxine overdose

Intralipid reverses coma associated with zopiclone and venlafaxine overdose

Decreased Fresh Gas Flow Cannot Compensate for an Increased Operating Room Temperature in Maintaining Body Temperature During Donor Hepatectomy for Living Liver Donor Hepatectomy

BackgroundThe purpose of this study was to compare the effect of various combinations of fresh gas flow (FGF) of anesthesia and different ambient operation room temperatures (ORT) on changes in nasopharyngeal temperature (NT) among living donors undergoing partial hepatectomy. MethodsThe anesthesia records of 167 patients were reviewed retrospectively. The patients were allocated into 4 groups: GI (n = 37): isoflurane in 2 L FGF and at typical ambient ORT (19°C–21°C); GII (n = 11) isoflurane in 1 L FGF and 1 L air at typical ORT; GIII (n = 31) isoflurane in 0.5 L FGF at typical ORT; and GIV (n = 88) isoflurane in 0.5 L FGF at ORT of 24°C.The changes in NT were compared using a two-way repeated measure analysis of variance (ANOVA) followed by Bonferroni post hoc tests. ResultsChanges of NTs of GIV were significantly higher compared with the other 3 groups, whereas the changes of NTs were the same among GI, GII, and GIII. ConclusionFGF of different volumes seemed to have no significant effect on intraoperative changes of NT in regular ORT. Low-flow anesthesia combined with ORT of 24°C provided significantly higher NTs at all measured points compared with GI, GII, and GIII.

‘The workman is worthy of his hire’* What is an anaesthetist worth in 2010?

‘The workman is worthy of his hire’* What is an anaesthetist worth in 2010?

Management of Profound Hypotension Secondary to Spinal Anesthesia: Simulation Case Scenario

DEMOGRAPHICS Case Title: Dante Jackson’s Anterior Cruciate Ligament (ACL) Repair (Cardiovascular collapse from a “high spinal”). Patient Name: Dante Jackson. Case Description and Diagnosis: A spinal anesthetic that results in cardiovascular collapse in a 24-year-old healthy male presenting for repair of the left ACL injury. Simulation Developers: Yetunde Olutunmbi, MD; William McIvor, MD; and Jessica Borrell. Dates of Development: June–December 2008. Target Audience: Medical students (4th year), Anesthesiology residents (post-graduate year 2–5), Anesthesiology faculty for continuing medical education (CME), student registered nurse anesthetist (SRNA), or certified registered nurse anesthetist (CRNA).

Contamination of laryngoscope handles

Despite use of sterile or disposable laryngoscope blades for each patient, disinfection of laryngoscope handles does not routinely occur, and these devices present a potential route of transmission of pathogens between patients and staff. A total of 192 specimens from 64 laryngoscope handles deemed 'ready for patient use' in the anaesthetic rooms of 32 operating theatres were semiquantitatively assessed for bacterial contamination. A further 116 specimens from 58 of the handles were tested for occult blood contamination. One or more species of bacteria were isolated from 55 (86%) of the handles, and included organisms such as enterococci, meticillin-susceptible Staphylococcus aureus, Klebsiella and acinetobacter. Cultures did not yield any anaerobes, fungi, meticillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci or multiply-resistant Gram-negative bacilli. No occult blood contamination was demonstrated. Although the majority of organisms isolated were not pathogenic, their presence indicates the potential for transmission of pathogens from laryngoscope handles. Strategies to address contamination of handles include revision of procedures for disinfection and storage prior to use, introduction of disposable handles or sheaths, and re-design of handles to eliminate knurled surfaces and contact points.

Ambulatory sinus and nasal surgery in the United States: Demographics and perioperative outcomes

Determine the prevalence of ambulatory sinonasal surgical procedures and perioperative outcomes in the United States. The National Survey of Ambulatory Surgery 2006 release was examined, extracting all cases of nasal or sinus surgery. Sinonasal surgical procedures were grouped according to septoplasty and/or turbinate surgery, sinus surgery, facial plastic surgery, and other procedures. Overall and group population-based sinonasal procedure prevalences were estimated from the sample. Frequency of general anesthesia, discharge status, and unexpected emergency room visit estimates were obtained. Perioperative complication rates for cardiac arrest, malignant hyperthermia, postoperative emesis, and blood transfusion were determined as well. Overall, an estimated 600,000 patients underwent ambulatory sinonasal procedures in 2006 with a mean age of 40.4 years and 53.7% male predominance. On a per patient basis, there were 260,000 septoplasties, 257,000 sinus cases, 134,000 plastics cases, and 103,000 other cases. Facial plastics procedures were less likely to use general anesthesia (72.8%) than the overall cohort (90.7%, P < .001). The vast majority of patients were discharged to home with an unexpected admission rate of 2.65%. Among the sample, there were no cases of cardiac arrest, malignant hyperthermia, or blood transfusion. The postprocedure emesis rate was 1.3%, not significantly different among procedure groups (P = .692). Only 0.1% of patients visited the emergency room postprocedure. Approximately 600,000 ambulatory sinonasal cases are performed each year in the United States. Complication rates and unexpected postprocedure mission rates are quite low indicating the safety and effectiveness of the ambulatory setting for sinonasal surgery.

Use of Oral Bromazepam as Premedicant and it’s Effects in Peri-operative Period - A Comparative Study with Oral Diazepam

Anaesthetic management begins with the pre operative psychological preparation of the patient and administration of a drug or drugs selected to produce specific pharmacological responses prior to the induction of anaesthesia. Preoperative medication should increase the likelihoods that patient will enter the preoperative period free from apprehension, sedated but easily arousable and fully co-operative. A prospective randomized controlled trial was performed in adult patient of different surgical approach to see the effectiveness of bromazeparn as a premedicant and the haemodynarnic changes in patients at perioperative period. Ninety patients of ASA grade I and II, aged 20 to 50 years of both sexes undergoing different type of surgery under general anaesthesia of 30 to 150 minutes duration and were divided randomly into three groups. Control group (Group-C) has no medication preoperatively. Group-D were given oral diazepam 5 mg at night before the operation and 5 mg at morning on the day of operation and Group- B were given bromazeparn 3 mg at night before and 3 mg at morning on the day of operation. Observations were carried in during preoperative assessment on the day before surgery, in the anaesthetic room at morning, before induction and in postoperative ward (after extubation). Anxiety level was measured by Visual Analogue Scale (VAS), which was reduced significantly at morning on the day of operation, before induction and 24 hrs after operation in Group-B (p&lt; 0.001). Pulse rate, blood pressure (systolic and diastolic) at different time in perioperative period (in Group-D and group Group-B) was stable in comparison to Group-C (p&lt;0.001). Sedation score that was measured at morning on the day of operation before induction in different groups was seen and found that in Group-D, (36.66%) patients were drowsy but responds to verbal commands in comparison to Group-B (6.66%) (p&lt;0.001). Recovery statuses were measured by Aldrete Recovery Score and have seen recovery scores was better in bromazepam taken group (73.33%) in comparison to diazepam taken group (56.66%). Postoperatively nausea was more in diazepam taken group (20.00%) than bromazepam taken group (16.16%). It was concluded that oral bromazepam at divided dose as a premedicant relief anxiety, and patients are haemodynamically stable in perioperative period with a well recovery. Journal of BSA, Vol. 18, No. 1 &amp; 2, 2005 p.22-30

Incisional Continuous Fascia Iliaca Block Provides More Effective Pain Relief and Fewer Side Effects than Opioids After Pelvic Osteotomy in Children

Intravenous opioid therapy is frequently used for postoperative pain management in children after orthopedic surgery but causes side effects such as respiratory depression, vomiting, sedation, and urinary retention. To investigate whether a continuous incisional fascia iliaca compartment (FIC) block provides more effective postoperative pain relief with fewer side effects than IV morphine, we performed a prospective, double-blind, randomized study to compare both techniques. Thirty children (ASA physical status I-II) aged 3 mo to 6 yr undergoing a pelvic osteotomy were included in the study. The children were randomized for either morphine IV and placebo (saline) via a FIC catheter (Group M) or placebo (saline) IV and ropivacaine via a FIC catheter (Group R). All patients received general anesthesia using inhaled sevoflurane and IV fentanyl. Perioperatively, a FIC catheter was placed by the surgeon. All patients received either a bolus dose of morphine IV (Group M) or ropivacaine 0.75% via the FIC catheter (Group R) at the end of surgery. Postoperatively, Group M received morphine IV 20 microg x kg(-1) x h(-1) and Group R ropivacaine 0.2% 0.1 mL x kg(-1) x h(-1) via the FIC catheter. In both groups, saline was administered along the other route. All children were assessed for pain, sedation, time until first oral intake, and adverse effects for 48 h postoperatively. During this period, all children had a urinary catheter. The study was completed by 28 children. In the anesthetic recovery room, children in Group M had significantly higher pain scores. These children were also significantly more sedated during the study period. The incidence of vomiting did not differ between the groups; however, children in Group R had first oral intake significantly earlier than Group M. A local retrospective study revealed an incidence of urinary retention of 4.7% in the ropivacaine-treated patients and 39% in the morphine-treated patients. Continuous incisional FIC block provides excellent postoperative pain relief, less sedation, and better return of appetite than morphine IV after pelvic osteotomy in children.

NICE guidelines for inadvertent peri‐operative hypothermia

We would like to report on our experience of introducing National Institute for Health and Clinical Excellence (NICE) guideline ‘The management of inadvertent perioperative hypothermia in adults’ [1] into our fast-track primary arthroplasty centre. We have conducted four audits of temperature management covering 353 patient episodes (the first two before the NICE guideline release). The overall impact of the guideline on our practice has been positive, such that in our last audit, 99% of patients were not hypothermic at any time. We have, however, encountered two key problems with the guideline. Our first concern is the relationship between pre-operative warming and not inducing anaesthesia below a certain temperature. Since NICE has used the same temperature <36 °C as the cut-off for both interventions, a trivial drop of 0.1 °C could result in the somewhat drastic measure of not inducing anaesthesia, without the opportunity to use an active measure to avoid this. In our experience, whilst the mean temperature of the population might remain the same between the ward and anaesthetic room, very few patients remain at exactly the same temperature; i.e. about half experience a drop in temperature. We feel there should be clear water between the temperature for active pre-operative warming and the cut-off for not inducing anaesthesia. The second issue relates to the surprisingly complex subject of defining normal temperature and therefore hypothermia. The difficulty for NICE is that there is enormous variability in normal temperature once age, gender, time of day, menstrual cycle and, most importantly, the method and site of measurement have been taken into account [2, 3]. We also recognise that NICE has had to take into account the views of stakeholders and the wider NHS procurement process when considering methods of measuring temperature. Nevertheless, the definition of normal temperature and hypothermia, and in particular how they relate to different measurement modalities, are fundamental to successful implementation of this guideline and should have been clearly and comprehensively communicated in the executive summary. Unfortunately, NICE has skirted around this subject in the summary and even within the full guidance, there is a failure to tackle the subject of monitoring adequately, as recognised by Harper et al. [4]. Using only the executive summary it would be easy to misinterpret audit results leading to inappropriate conclusions about performance and, if the indication to not induce anaesthesia is observed, significant theatre inefficiency (Table 2). A correction factor should be applied to non-core temperature measurements, which can be found on page 202 of the full guideline [1].

Pride and prejudice

Pride and prejudice

Numbers of Simultaneous Turnovers Calculated from Anesthesia or Operating Room Information Management System Data

More personnel are needed to turn over operating rooms (ORs) promptly when there are more simultaneous turnovers. Anesthesia and/or OR information management system data can be analyzed statistically to quantify simultaneous turnovers to evaluate whether to add an additional turnover team. Data collected for each case at a six OR facility were room, date of surgery, time of patient entry into the OR, and time of patient exit from the OR. The number of simultaneous turnovers was calculated for each 1 min of 122 4-wk periods. Our end point was the reduction in the daily minutes of simultaneous turnovers exceeding the number of teams caused by the addition of a team. Increasing from two turnover teams to three teams reduced the mean daily minutes of simultaneous turnovers exceeding the numbers of teams by 19 min. The ratio of 19 min to 8 h valued the time of extra personnel as 4.0% of the time of OR staff, surgeons, and anesthesia providers. Validity was suggested by other methods of analyses also suggesting staffing for three simultaneous turnovers. Discrete-event simulation showed that the reduction in daily minutes of turnover times from the addition of a team would likely match or exceed the reduction in the daily minutes of simultaneous turnovers exceeding the numbers of teams. Confidence intervals for daily minutes of turnover times achieved by increasing from two to three teams were calculated using successive 4-wk periods. The distribution was sufficiently close to normal that accurate confidence intervals could be calculated using Student's t distribution (Lilliefors' test P = 0.58). Analysis generally should use 13 4-wk periods as increasing the number of periods from 6 to 13 significantly reduced the coefficient of variation of the averages but not increasing the number of periods from 6 to 9 or from 9 to 13. The number of simultaneous turnovers can be calculated for each 1 min over 1 yr. The reduction in the daily minutes of simultaneous turnovers exceeding the number of teams achieved by the addition of a turnover team can be averaged over the year's 13 4-wk periods to provide insight as to the value (or not) of adding an additional team.